Cover
Ex sum
TOC
CHAPTER 1 INTRODUCTION 1.1 Background to the proposed project
Kandy is the hill capital of Sri Lanka, situated 823 meters above sea level. It is also the capital of the Central Province, the most beautiful cultural city in Sri Lanka, which been declared a World Heritage City. Since then, the importance of Kandy increased. Many people, Buddhists and other religionist from all over the country and the world visit the holy place of Sri Dalada Maligawa (The Temple of the Sacred Tooth Relic of Lord Buddha) in the city centre, besides there are other historical sites and monuments within the Heritage city attracting more and more tourist each year. There are number of temples with historical importance scattered in the small villages surrounding the city. Some of villages have artisans with great skills producing artefacts of great value. The traditional Kandyans in these villages live a very healthy life while producing spices, fruits and vegetables for local and export markets. Similarly, Kandy city dwellers and travellers too enjoy the cool climate of this beautiful city surrounded with its hills and valleys, rivers, lakes and cascading waterfalls. This picturesque city with the importance of being the capital of the Central Province has had a greater impact on the life of the city for several decades with number of renowned schools and centres of higher education including the University of Peradeniya, which is located within the periphery of the city. Therefore, it attracts a large student and professional population from outside. The expenses of the Kandy Municipal Council (KMC) to provide adequate services on health and sanitation among other services are noteworthy. The Central Government interventions to ameliorate the disposal facilities still would reply on additional expenses to maintain the improved system of managing the ever increasing generations of Municipal Solid Waste (MSW). In response to such increases, up to 1960 Gohagoda, which is 7km away from the city was used as an isolated area for dumping hospital waste, then as a sewage dumpsite and finally as the place for dumping all the waste generated from the KMC. In year 2003, the dumpsite was semi engineered with the technical and financial support of the Japan International Cooperation Agency (JICA) for increasing its capacity for two years. Nevertheless, still Gohagoda is the final disposal site for solid waste generated in city of Kandy. Unfortunately, at present 120 tonnes of MSW per day collected in the city are being dumped at the Gohagoda dumpsite. It is even worse during the festival season. It is a huge threat in terms of air pollution due to Green House Gases (GHG) and odorous gas emissions. In addition, emissions pollute the Mahaweli River, which is the main water source for entire province. In addition to that, due to highly contaminated through deep percolation and seepage is polluting the groundwater table. As a result, significant numbers of communities are facing various diseases and health problems, more frequently.
Therefore, open dumping is no longer acceptable for Kandy city and Central Environmental Authority (CEA). Alternate technologies and safe disposal facility are essential to overcome the plight of poor MSW management. In addition, it is essential to rehabilitate the dumpsite, otherwise it will continue to pollute for a considerable length of time. Unfortunately, the rehabilitation of dumpsites was not strongly emphasised within the government policy and thus, not given the priority, until recently in the wake of the crisis at Bloemandhal, Colombo. However, open dumping is no longer acceptable for Kandy city, since lack of land and other negative issues of open dumping. Therefore, ECOTECH LANKA has taken the initiative and responsibility to apply suitable waste treatment technologies for minimizing environmental pollution. Waste to Energy (WTE) concept is an ideal option, which not only considers the environment but also generation of energy from MSW. Thus, application of WTE concept is more feasible for polythene, plastic, rubber etc. and recyclable component of mined waste. Based on energy values found for different type of waste within the Kandy Municipality, it is possible to generate a significant percentage of energy requirements using the wastes discarded at present. It is proposed to extract compost and convert it to char from the mined waste for plantations and remaining plastic and other polyethylene to be converted to Residual Derived Fuel (RDF) while extract the landfill gas and produce electricity as a prime income source to commence other project activities. It is obvious that with implementations of these activities, it would be possible to uplift the living standards of the communities via more income generation and protect the environment for future generations while mitigating present serious environmental burdens. The KMC opted to develop a corporate partnership with the University of Peradeniya, since the University has developed number technologies that can resolve the present constraints and also provide low cost technological options to rehabilitate the Gohagoda dumpsite. There were several promotional events conducted jointly between KMC and the Postgraduate Institute of Agriculture (PGIA) to formulate the project “Rehabilitation o f Gohagoda Dumpsite and Development of an Integrated Solid Waste Management (ISWM) System for KMC”. 1.2 Justification of the project
The KMC while approving the project recommended and sanctioned to formulate a company to undertake the proposed project, since none of the companies tended the expression of interest (EOI) were willing to rehabilitate the dumpsite and dispose the wastes without a tipping fee. Therefore, EcoTech Lanka Limited formed to implement the project with the intention of deriving funds from other sources, so as to convert the wastes to tangible resources. The plausible conversion technologies are composting, since the composition analysis of the wastes indicates that more than 60 % of waste is short-term biodegradable that is ideal for producing compost. However, the quality of compost is questionable. The better alternatives are converting the compost to char and to establish landfill bioreactors to generate gas for power generation. It also blends well with the gas generations from the dumpsite that can contribute to developing a sustainable system. This was one of the
reasons to continue disposal of wastes at Gohagoda, since the earlier proposal of finding an alternate site was shelved due to many reasons such as Not In My Back Yard (NIMBY) syndrome, haulage distance, social and political pressures. Nevertheless, rehabilitation of the dumpsite is a challenge requiring adequate funding with suitable technologies of making RDF and char fertilizer. Also additional funding is a necessity for social adjustments of the rag pickers and farmers rearing animals, thus housing and developing improved livelihoods. The gas emissions from the dumpsite can be captured to produce electricity. This will contribute to the reduction of climate change and global warming. However, emissions need treatment before allowing it to flow eventually to Mahaweli River. The income from electricity generation should be more than adequate to override the costs of rehabilitating the dumpsite. The exploitation of the dumpsite resources can commence with the correct choice of technology to establish the ISWM system. Unfortunately, most of the available technologies in developed countries are operated inefficiently, since the management of facilities depends on high tipping fees. Therefore, optimization and development of scientific principles are lacking in most of the processes that are installed in most Western Countries. They are now in the process of developing ISWM systems. Still the waste management professionals either belong to engineered landfills or incineration systems. The strides made at the University are to combine the two technologies to make the system truly integrated. In the process of reaching that target, it has been possible to find inventive ways of managing sustainable landfills with the landfill bioreactor technology at low costs. The efficiencies of the existing thermal systems can then be improved with much higher temperatures of combustion by combining landfill gas with producer gas to meet ambient air dioxin emission standards. In view of these novel approaches the Company has decided to initially install a 2.5 MW duel fuel system and finally a 7.5MW thermal power plant. In addition, other supporting technologies are available to increase profitability and thus reduce risk. 1.3 Objectives of the project
The impact on environment and thus, the health of the populations are affected due to the open dumping of wastes at Gohagoda. It is essential to rehabilitate the dumpsite and develop a sustainable ISWM system for KMC and other neighbouring local authorities while providing a healthy livelihood for the families who are dependent on the wastes. It is essential to develop the sustainable system at Gohagoda without causing any hindrance to other Kandian villagers of cultural and historical values. 1.3.1 Main objective(s) of the project
To implement the 30 year lease agreement given to the company to establish and operate an ISWM system for the KMC which will be implemented in stages with proven technologies while the dumpsite is rehabilitated to meet environmental standards of the CEA.
1.3.2 Specific objectives
i.
To remove haphazardly dumped wastes, process the existing materials, treatment of and extraction of gas in the rehabilitation efforts. ii. To improve the infrastructure so as to access the dumpsite and operate it until landfill bioreactors can be constructed and used. iii. To conduct preliminary works on awareness programmes while the collection system is improved. iv. To relocate the occupants to a safe and socially acceptable habitats approved and given by the KMC v. To undertake preliminary scientific and technological investigations to develop detailed designs, construct and operate landfill bioreactors in an integrated approach vi. To promote avoidance, reduction, reuse and recycle of materials while assisting the KMC to improve collection of wastes vii. To maximise conversion of waste to energy by promoting biochemical (biogas) and thermal processes (RDF) to generate electricity and other thermal uses 1.3.3 Objectives of the EIA report
It is a necessity under the National Environment Act No 47 of 1980 (NEA) to carry out an Environmental Impact Assessment (EIA) study considering the fact that the proposed ISWM system will be receiving more than 100 tonnes of waste per day and a dumpsite mining and rehabilitation component has been suggested as part the project Ecotech Lanka Limited, Solid Waste Management Research Unit (SWMRU) of the University of Peradeniya together with other experienced experts evaluated the present environmental impacts and possible impacts that could arise through rehabilitating of the dumpsite and during establishing and operational phases of the ISWM system with special emphasis on converting waste to energy and then to mitigate them with appropriate techniques so as to minimize the adverse impacts on the environment. In this respect, special attention was paid to groundwater, surface water contamination, air quality as a consequence of generation, landfill gas emission and emissions during RDF processing and utilization. Further this report attempts to provide a suitable monitoring programme to ensure the adherence to the proposed mitigation measures. 1.4 Brief outline of the methodologies and technologies adopted in EIA preparation
The scope of this EIA mainly covers the Terms of Reference (Annexure 1) prepared by the CEA, the Project Approving Agency. The study area in general covers the entire land allocated for the project. Social study covers 500 m radius outside the proposed area. Every effort was exercised to capture the likely affected areas. The study involved the collection of baseline data on the existing environment. In this respect the University Peradeniya with the collaboration of the Institute of Fundamental Studies (IFS) carried out physico-chemical and microbiological analysis of surface water, groundwater and sediment quality in the project area. Soil types and bore-hole analysis were too carried out. The field observations, field and laboratory analysis conformed to
standard methods. National Building Research Organization (NBRO) was contracted to measure air quality and noise levels in the project area. Different surveys were undertaken by the experts in order to collect relevant baseline data as appropriate as possible. The methodologies adopted for this study are summarized in Table 1.1. Literature, surveys, questionnaires, field visits, meetings and discussions and computer modeling work that are usually adopted in EIA studies were used. Impacts were evaluated using the Leopold Matrix method. 1.5 Compatibility with other projects/programs/plans/developments in the area
The Kandy City development under heritage city indicates positive improvements to traffic by way of one way, overhead bridges, underpasses and even mono-rail and thus, the waste transportation system can be improved. The water intake project is somewhat a problematic or a concerning factor for the development of the project. The balancing tank in the middle of the waste dump and the proposed landfill bioreactors was not located appropriately in the design and construction of it. Although, the present dumpsite is having an impact on water quality before treatment at the Katugathota water purification plant, the proposed ISWM system will reduce the impacts, thus ameliorating the conditions for supplying intake water. The sludge beds to be constructed in the promises of the Gohagoda facility by the Kandy national water supply and drainage board (NWS&DB) will cause odour problems. But it can be compatible if the sludge is processed by the proposed ISWM system. It can be processed to produce good quality fertilizer by charring or sterilization and drying with steam generated from the power plants. The Gohagoda temple is very old and has a long heritage. It serves the communities living around the dumpsite. It is deeply felt that the prosperity of the project is blessed with this temple located at the edge of the dumpsite. The prelate of the temple has already provided numerous advises and solutions. Therefore, the company is envisaging greater involvement of the temple to improve the spiritual and educational levels of these deprived populations living in the neighbourhood. This small temple requires restoration to become one of the leading religious locations not only for workers and their families employed by the company. . Tourism: The odour nuisance is one of the greatest impacts for hotels located on the other side of the Mahaweli River and in some places quite far from the dumpsite. The challenge is then to ensure odour free facility enhancing the environment to increase the tourism industry largely dependent on the Mahaweli River. 1.6 Policy, legal and administrative framework with reference to the project
In Sri Lanka, the basic legal framework required for solid waste management is provided under an umbrella of Government, Provincial Council and LA regulations and legislations.
The 13th Amendment to the constitution (1987) and the Provincial Councils Act No. 42 of 1987, the sections 129, 130 and 131 of the Municipal Councils Ordinance (1980), Sections 118, 119 and 120 of the Urban Councils Ordinance, No. 61 of 1989, Sections 41 and 93 to 95 of the PS Act, No. 15 of 1987 and National Environmental Act (NEA) are the key pieces of legislations governing solid waste management. According to the MC Ordinance, the urban council (UC) Ordinance and the pradeshiya sabha (PS) Act, all MSW generated within the boundary of local authorities (LAs) is their property, and they are mandated to remove and dispose of such waste materials without causing any nuisance to the public (Vidanaarachchi et al., 2005). These government enactments provided the provisions and regulation for selecting a suitable lands for the project and help to do the development within the frame of law and regulations. One of the very important acts relevant to above mention project is national environmental act. The provision of the act vindicate and explain how to launch the project without damage to the environment. Other acts, Ordinance, regulations applicable to the project are provincial council ordinance, Electricity act and regulations impose by the ministry under the national environmental act. etc. the Sri Lanka labor law applicable to laborers/ Workers/ Employers and others who are relevant to that field.
As a response to the growing problem, the Ministry of Environment and Natural Resources has planned an implementing programme, called “Pilisaru” to coordinate the efforts of all stakeholders, including the urban planners. One of the aspects of the programme was to develop appropriate policies for developing sustainable systems. It has been gazetted and enforced. A strategy based on the policy framework is also implemented to encourage solid waste management practices through waste avoidance, reduction, re-use, recycling, treatment and final disposal. Further, the strategy recommends that all LAs provide proper landfills for final disposal. Also it emphasizes the importance of these developed policies in order to support existing and developing economic, industrial and urban planning policies. 1.7 Approvals needed for the project from other state agencies and any conditions laid down by Government agencies for implementation of the project
It has been envisaged that approvals are necessary from key institutions in charge of different subjects during rehabilitation of Gohagoda dumpsite and development of an ISWM System. They are as follows; - Harispathuwa Pradeshiya Sabha - Mahaweli Authority - Central Provincial Council - Ministry of Environment and Natural Resources - Ministry of Local Government and Provincial Council - Urban Development Authority - Ministry of Power and Energy - Central Environmental Authority The conditional approvals except from CEA have been already received and are given in Annexure 2.1.
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Commitments from the local authorities to supply garbage for the project
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Letter of intent (LOI) from the CEB for purchase of electricity
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Provincial approval from the SEA
CHAPTER 2 DESCRIPTION OF THE PROJECT REASONABLE ALTERNATIVES 2.1 Description of the Project 2.1.1 Project site
The proposed project site is the present final disposal site of the KMC, which is 30 years old unmanaged open dumpsite known as Gohagoda Dumpsite. It is located in Thekkawatte, Gohagoda, at about 1.5 kilometers from Katugasthota town on Sri Rathanapala Mawatha (B365), well known as Katugasthota-Peradeniya road, 200 meters off the left side at Gohagoda junction. The location belongs to Polwatte Grama Niladhari division in Harispattuwa Divisional Secretariat Division and Harispattuwa Pradeshiya Sabha in Kandy District of Central Province of Sri Lanka. The extent of the proposed project site is around 16 acres on the left bank of the River Mahaweli. The land is owned by the KMC and leased to Ecotech Lanka Limited for 30 years. A copy of the Lease Agreement is annexed in this report (Annexure 2.2). Figure 2.1 is a map of the proposed location and Figure 2.2 is an aerial view indicating accessibility to the site, surrounding developments and infrastructure.
Proposed Project Site at Gohagoda
Figure: 2.1 Map view of the proposed project site
Katugastota - Peradeniya
Site Access Road
Dumpsite
Mahaweli River
Proposed Project Site at Gohagoda
NWS&DB Water Intake
Proposed Site for Kandy Sewerage Treatment Plant Sludge Processing Unit by NWS&DB
Figure: 2.2 Aerial view of the proposed project site
2.1.2 Nature of the project a. Waste Collection System i. Sources and amount of waste to be collected
Residential, commercial, street sweepings and the industrial waste other than sewage sludge are the main sources of MSW. At present, the waste generation within the Kandy city is around 215 tones/day and according to the loading survey conducted at the disposal site, 110.12 tones/day is collected by the KMC and disposed at the Gohagoda dumpsite. This includes market waste from Kandy central market, Manikkumbura public market, temple of Tooth Relic, Kandy general hospital, Peradeniya general hospital, and other institutional waste including schools, banks, private and public offices. Besides, waste generated at the University of Peradeniya, Mahaweli reach hotel, industries (Ceylon Tobacco Company, distilleries), Infectious Disease Prevention (IDP) unit and Harispaththuwa Pradeshiya Sabha collection and disposal by themselves. Amount of
waste collected from different sectors is given in Table 2.1 and details of the loading survey are given in Annexure 2.3.1 and Anex. 2.3.2
Source of Waste Generation Households and Commercials Kandy Central Market Manikkumbura Public Market University of Peradeniya Hospitals Mahaweli Reach Hotel Ceylon Tobacco Company Distilleries IDP Unit Total ii.
Amount of waste Collection tonnes / day
79.60 08.27 04.67 01.50 04.72 00.68 00.15 01.92 08.61 110.12
Nature of waste
MSW composition could vary from place to place according to the location, population density, income level and social background (Wang and Nie, 2001). As reported by Manikpura et al., 2007 the composition of waste collected by Kandy Municipality averaged as shown in Figure 2.3.
Figure 2.3: Composition variation of MSW in Kandy Municipality
It shows that readily biodegradable is the highest fraction which is about 59.2% and long term biodegradable portion is about 29.27%. The market waste has higher organic fraction. University and hospital waste could contain hazardous waste, obviously.
iii.
Waste collection process
The KMC is the responsible authority to manage waste within the Kandy Municipality.
The present vehicle fleet for MSW collection consists of compactor trucks, open tractors and handcarts. Compactor trucks and tractors are used to collect the waste from main roads while push carts are used for narrow roads and lanes, which are then transferred to the tractors or compactor trucks. Frequency of collection varies from place to place ranging from three times per week to once a week. KMC area is divided in to 5 zones according to the collection of SW as given in Table 2.2.
Zone
Sub Zones
Zone 1
1A
Central City
Kotugodella, Yatinuwara, Wewelpitiya
1B
Deiyanewela
Ampitiya, Malwatta, Deiyannewela
KMC
Mahaiyawa
Bahirawakanda, Nuweea, Dodanwela, Asgiriya, Mahaiyawa
KMC
Zone 3
Peradeniya
Peradeniya, Mulgampola, Katukele, Suduhumpola, Siyambalapitiya, Bowala
KMC
Zone 4
Katugastota
Mapanawathura, Katugastota, Mawilmada, Kahala
KMC
Zone 5
Arruppola
Watapuluwa, Lewella, Buwelikada
KMC
Zone 2
Area
Wards
Responsibility
Carekleen(Pvt)Ltd.
Annexure 2.3.3. illustrates the management structure of waste collection process in KMC including labour forces. Proposed project expects to continue with this management structure while resolving the existing problems and providing adequate resources. Tools such as mamoties, shovels, pickaxe, rakes, forks and knifes are used to collect the waste. But in some zones tools are not enough, because lacking of replacements, when need arise. Handcarts are used in primary collection for discharging their loads of garbage to community collection points (open, closed, non-permanent concrete bins), from where the waste is picked up again by tractor/compactor labors and loads in to the respective collection vehicles. In some places in Arruppola zone, collection crew is directly collecting the waste from the sources (houses, shops) without transferring to primary collection points. At present all five zones are collecting mixed waste without any separation. In future, the source separation and bell collection system will be introduced. Most likely it will be commence from the Aruppola zone.
iv. Haulage system to transfer waste from the primary collection areas to the proposed site including transfer / collection stations
Concrete bins and barrels are used as primary waste collection points. However, most of the concrete bins are not in proper conditions due to animal interferences, insufficient roofing, loading problems and not located at suitable locations. Further, there are temporary locations which are used to dump waste directly on the road sides without any cover. Those places will be replaced with a well planned waste collection system after conducting a survey on those areas. Therefore, conditions of the collection points will be improved by changing the structure to unload waste directly to the compactor or tractor and it will facilitate the collection of source separated waste. Details of the primary waste collection points given in Table 2.3. Table 2.3. Details of primary waste collection points Zone
1A 1B 2 3 4 5
Permanent concrete bins Closed
24 8 9 5 20
Opened
8 12 22 8 0
Barrels
Non permanent places
Total
6 21 1 10 0
48 52 41 31 23 20
3 6 4 0 5
Most of the places do not require a transfer station, except at the IDP section. Since, it necessitate locating a transfer station to collect waste into 2 tractors and 2 compactor trucks within the Kandy city limit especially during the festival season like Asela Perahara. The expected haulage road net work for the waste collection and transport has explained in Annexure 2.3.4 for each zone with the time schedule. Frequency of collection varies from place to place but most places daily collection is practiced.
v. Method of transportation and type of vehicles used
Waste is transported using tractors and compactor trucks (see Plate 2.1) as mentioned in above sections. Handcarts are used in transporting waste to the primary waste collection points and tractors are used to transport waste from primary waste collection points to the Gohagoda dumpsite. Hand Cart
Tractor
Plate 2.1 Type of waste transport vehicles
Compacter Truck
A summary of details available vehicles and frequency of waste collection and transportation expected from each zone are given in Table 2.4
Waste Collectio n Zone
Zone 1
Zone 2 Zone 3
Waste Collection Area
1A Central City 1B Deyyannewela Mahaiyawa
Number of vehicles Number of trips Number of vehicles Number of trips
Peradeniya Katugastota
Zone 4
Zone 5
Details
Manikkumbura market Arruppola
Number of vehicles Number of trips Number of vehicles Number of trips Number of vehicles Number of trips Number of vehicles Number of trips Number of vehicles
Compactor trucks
Tractors
4 0 12,13 0 1 1 2 5 per week 1 1 2 3 1 2 4 2 1 2 3 8 0 1 0 1 0 2
Hand Carts
48 17 10 13 20
In order to ensure the anticipated quantities of solid waste receiving at the site during the operational period, and KMC is collecting the total quantities at present, a questionnaire survey was conducted to assess the present conditions of vehicles (see Plate 2.2). According to that, the variation of the transport capacity of vehicles is given in Table 2.5. Table 2.5. Transport capacity of vehicles Transport capacity
Number of vehicles
Percentage
< 1500kg
3
13.04
1501 – 3000kg
16
69.56
>3000 kg
4
17.40
Total
23
100
According to the survey results, there are several problems and shortcomings associated with waste transportation vehicles such as falling of waste from vehicles (63% of vehicles are opened and 37% are closed), leakages of oil, not enough labors (37% of vehicles have 4 labors and others have less than four), leakage of water from the radiator, missing body parts (lights, speedometer, seat belts, safety guards, fuel gauge, air pressure gauge, etc.) and problems in hydraulic system. These limitations will be resolved to give efficient waste transport
3 7
system for the proposed project. Details of assessed vehicle conditions are given Annexure 2.3.5 ...
Plate 2.2 Vehicle conditions assessment
Nevertheless, almost all the vehicles have proper documentations like insurance, revenue licenses, copy of the certificate of registration and maintenance reports. Maintenance of 70.4% of vehicles (KMC vehicles) is done in the municipal workshop at Katukele. Others are maintaining them by their own places. vi. Principal haulage routes and traffic management plan
vii. If hazardous waste is collected, the collection and haulage system
Hazardous waste could be collect separately in parallel to the source separation. Especially, hospital wastes except the hazardous waste other types of waste will be collected. Hazardous waste will not be accepted by the proposed project. viii. Alternative roads for waste transportation
There are no alternative roads to transport waste. b. Waste pre-processing i. Method of pre-processing
In the initial stages of the project, pre-processing activities will be minimal. The existing warehouses will be renovated and use for this purpose and to store electronic wastes (ewastes). Then a Materials Recovery Facility (MRF) will be constructed to promote 3R (Reduce, Reuse, Recycle) system. The facility will be fully functional when the point source separation programmes are successful, such that prior sorted wastes will then be
separated and graded to different categories of wastes. The vehicles that are transporting non-biodegradable or long term biodegradable will enter the facility that has the storage section. The biodegradable wastes will be sent directly to the landfill bioreactor cells or transferred to awaiting haulage trucks. Then, the haulage trucks are the only trucks that will take biodegradable and mixed wastes to the landfill bioreactor cells. ii. Equipment to be used
Conveyor belts, lifts, extruders, pumps, exhaust fans, firewood splitter and fans will be used for different activities. One of the precision extraction works for e-wastes will have air conditioned (AC) facility. An electrically driven forklift is essential for lifting pallets with relatively high loads. iii. Requirement of power for pre-processing activities The power requirement for pre-processing activities is given in Table 2.6. Table 2.6 Requirement of power for pre-processing activities
Item
Description
Qty Power consumption (kW)
1.0
Conveyor belts
2
8
2.0
Lift
2
7
3.0
Extruder
1
8
4.0
Pumps
2
7.5
5.0
Exhaust fans
5
4
6.0
Fans
10
15
7.0
Firewood splitter
1
3
8.0
Power saw
2
2
9.0
Precision extractors
6
12
10.0
Air conditioners
5
15
11.0
Forklift
1
13
c. Rehabilitation of the existing dumpsite i.
Details of clearing, levelling & embankment construction
The dumpsite was not accessible due to poor management of the dumpsite by the Municipality. The end result was dumping of wastes in three of the convenient locations causing tremendous hardships to the people living near by these disposals. It was also directly polluting the River. These dumps were cleared using 240 hours of excavator and two dump trucks. The cost of the entire operation was Rs1,890,000. The road network was developed to work under all weather conditions and followed by hauling the sprawling wastes over the embankment and embankments were levelled with the wastes and compacted to form stable sides. The composite liner system of clay and waste polyethylene was applied on the compacted first terrace on the bench level of 476 from mean sea level. The next embankment will be constructed and again the composite
base cover will be applied to minimise gas emissions. On top of this layer, a soil layer applied to turf the entire surfaces of sides and embankments. The top of the dumpsite is to be levelled to have a 2% gradient on both sides towards the lower part of the dumpsite. ii.
Installation of vertical barriers (if any)]
The hydrogeological study found that there is a confined rock outcrop and stable soil supporting surcharge loads of the dumped wastes. It seems that there is hardly any seeping through the parent materials that is supporting the wastes. Instead, it is evident that is weeping from the embankment. Nevertheless, provisions are made to construct a vertical barrier near to the natural drain. iii.
Details of capping of the dumpsite
In order to ensure sanitary conditions, it is proposed to apply a daily cover of compost extracted from old wastes dumped on oldest disposals around the main dumpsite or soil. The dumpsite will be completely covered with composite cover, soil and turf. This finial cover will be applied at the finish level of 479. The completion of cover will be after installing the gas extraction system to a depth of 6 m and it will depend on the establishment of landfill bioreactor in Phase II constructions. iv.
Availability of cover material
The estimated quantity of compost cover materials is approximately 1430 tonnes. It is more than sufficient to use as daily cover materials. However, the availability of clay is restricted to the river banks and it may cause environmental problems. Alternatively, the available clayey soil from a borrow pits at Aladeniya, Muruthalawa and Nanuoya could be used with increased thickness and additional quantity of polythene wastes. Also there are considerable quantities of clayey soils illegally disposed along roadsides that can be recovered. Some of them are mixed with construction and demolition (C&D) wastes. It is proposed to extract clay from these soils, so that made up clay can be a useful substitute for the cover and liner systems. v.
Gas extraction and storage system including anticipated quantity and quality of gas to be extracted
Similar to the liner, the capping of the dumpsite is constructed to maintain a live biocap. The waste polythene sandwiched between clay allows water to enter but prevents escape of gases, as long as the live biocap remains above field capacity. When the capping is undertaken, gas wells are installed and they will be installed at different depths to compensate the level differences between terraces, such that deeper wells will be installed 8m and shallower at 6m. The radius of influence is 12m for all of the wells. In addition, it is envisaged to install some of the wells on the embankments to capture maximum gas. The safe extraction level is 12.3m3 /min and the expected quality is given in table 2.7. A 5kW blower or a vacuum pump is needed to main a minimum vacuum of 14.2kPa in the well head. After number of tests, it was found that the intrinsic permeability of the wastes was found to be 3.2x10-11 cm2. Thus, it will create a total vacuum of 18.15 kPa at the inlet of blower as shown in the calculation given in Annexure2.5
vi.
Gas flaring system
The following figure 2.4 shows the landfill gas flaring system.
Gas Pressure and Flow Measurement
Flare Stack
Condensate Knockout Gas Blower Flame Arrester
Figure 2.4 Gas flaring system
Table 2.7 Gas quality
vii.
collection and treatment system
generation and collection The generation and quality is described in detail in section 3.3. It is necessary to construct subsurface drains up to the embankment level of the rehabilitation done in 2003 and drains cut in the embankment to lead the flows to the toe of the embankment. However, without weakening the toe, thus considerable quantity of backfilling required. Therefore, it was decided to lay perforated pipes with aggregate backfill of sizes from 25 mm and 40 mm at the top of the cut drain as shown in Annexure2.6 An additional subsurface drain of the same specification was installed on the North East end of the embankment, since s were oozing out due to the natural slope. Draining the and collection not only lessen the environmental impacts but also reduce the pore water pressure exerted on the waste embankments with soil on the outer surface built in 2003 and now in 2010. The subsurface drains were specifically designed to cater the rate of permeating from the sides of embankments. Therefore, the pipes were perforated with 2mm slots and 25mm long and depending on the permeability results the slots were made 33%, 66% or 100% of the circumference with spacing between slots, see Annexure... It is very important to make slots to ensure
continuous flows without blockages, rather than circular perforations that were made in the pipes installed in 2003 of the JICA rehabilitation efforts. Treatment Manikpura et al., 2008 did did estimate generations using the HELP model model to be as much much as 3 30,304m /year. Notably with additional waste disposals, the recent study reveals a higher figure of 30, 810m3 /year. The average BOD and COD values were 7,500 mg/l and 30,000 mg/l. Therefore, the treatment system should be robust and capable of reducing the value to 30mg/l to discharge the treated . The present systems cannot achieve such low values without having to rely on chemical treatment. Instead, biochemical means are being researched with very marginal advantages. Nevertheless, bioreactor technology with the liner system and recycling of can reduce it to manageable manageable values of 500 mg/l to 1500 mg/l in less than 90 days. The Figure Figure 2.5 illustrates the performance of the landfill bioreactor „test cell‟ with fresh wastes. A similar concept can be used for treatin g the s generated from the dumpsite.
90500 80500 70500
BOD
) 60500 l / g 50500 m (
COD
40500 30500 20500 10500 500 500 0
50
100
150
200
250
300
350
400
Time (days)
Figure 2.5 The performance of the landfill bioreactor ‘test cell’ with fresh wastes
Therefore, a bioreactor can be designed to have an estimated hydraulic retention retent ion time (HRT) of one day and solid retention time (SRT) of 14 days under anaerobic conditions. It will be sufficient to reduce high BOD and COD values to low values that could approach less than 500 mg/l of BOD. In order to reduce overloading at high values and to ensure a SRT of 14 days, there should be two reactors. Each one operated alternatively between active and passive modes. In the active mode both influent „‟ flow and effluent flow takes place with recirculation recirculat ion of , whereas in passive mode, recirculation of the stored takes place with few discharges depending on the rainfall and irrigation. In this manner, solid build up is restricted to 14 days. The seven day cycles reported in many of the publications (ref………..) points towards a natural cycle of 28 days. Thus the SRT can be increased from 14 to 28 days, depending on the required quality of the effluent.
The discharged effluent having strengths of less less than 500 mg/l mg/l BOD from from the bioreactor will be pumped to the existing two Activated Sludge Process reactors measuring 287 m3 and 261 m3 constructed in 2003 for treating sewerage gully discharges. The design of the ASP is different because the aeration is with 4 numbers of air guns providing sufficient oxygen for physiochemical process by adding alum for flocculating the . The expected duration of treatment is six hours. In fact, the design criteria were based on the laboratory experimentation done to reduce the BOD to meet CEA standards. The criteria are given in Figure 2.6 and Figure 2.7 for settling the flocculated mass in the second reactor. The settlement time is 3 hours.
Figure 2.6 Design criteria criteria for treatment bioreactor
Figure 2.7 Design criteria for settling tank for flocculated mass
After settlement, the effluent is discharged into the Constructed Wetland and then finally to the watercourse. The sludge is removed and dried for subsequent thermal treatment to oxidise further the ion compounds. The sludge can be used as filler materials for making cement blocks, refer section k. viii.
Permanent and temporary structures
The treatment plants of bioreactor, sludge drying sheds and activated sludge sludge process (ASP) reactors are permanent structures. The bioreactors bioreactor s will will be rehabilitated once in three to five years. There will be movable temporary sheds for mining the dumpsite during rainy weather conditions. The newly constructed site office is temporary, until the administrative complex will be established; see layout plans given in Figure 2.31 and Annexure…. ix.
Fire protection system (if any)
There will be irrigation system established to douse fires in the dumpsite and landfill bioreactors. Furthermore, stocks of clay will be available to douse any fires, so as to prevent cavities within the dumpsite or landfill body. It will be a filler material and an effective sealant. Furthermore flame arresters will be installed at landfill gas flare station to protect the system from backfire; refer Figure 2.4. x.
Off site disposal of waste material (if any)
The dumpsite may have materials that cannot be recycled. It will be recovered and stored for subsequent disposal in the inert landfill built in the last stage of development. Until then, these materials, like e-wastes will be stored in the existing warehouse and in the demarcated lands for final disposal marked in the layout plan, see Figure 2.31 and Annexure…. d. semi-engineered landfill
i.
Extent of the site
It is proposed to extend the dumpsite, in the event that the dumpsite is inaccessible. The location as given in Figure 2.8 and Annexure is in between the dumpsite and the road leading to the treatment plants. L B R 2
S ub s urface l eachat ep i pe S urfacewat er drai n
L B R 1 -
Exi s ti ng D u m p
S o e l i m b a n k m e n t and t hecul v ert
S ub s urface l eachat ep i pe S urfacewat erdrai n
P ropos edex t en t i o n t o t hedumps i t e
Figure 2.8 Proposed location for semi-engineered landfill
ii. Process description A soil embankment will be constructed in between the two embankments to retain the wastes. Before constructing the embankment, a culvert will be constructed as shown in Figures 2.9 and 2.10. It will be underneath the embankment. This earth embankment, the embankment of the dumpsite and the firm ground on the side of the road will be lined with the composite clay-waste polythene liner. The surface drain will be covered with reinforced concrete half circular covers to withstand point and surcharge loads. They will be placed with 25mm gaps between the covers. A layer of 40 mm and 25 mm sized aggregates will be used as backfill and a soil layer will be placed above the backfill. The composite liner constructed above it, thus allowing purified water to percolate down to the drain. Above the composite liner, another 10 to 25mm 25mm sized sized aggregate layer will be placed with a central pipe, having an envelope of these aggregates ra pped pped with a „geonet‟. The pipe will be connected to a stilling well. The base constructions construct ions including establishment of gas wells, will ensure direct disposal of wastes without allowing any heavy vehicles moving over the wastes.
Figure 2.9 The culvert through the bund of semi-engineered landfill
Figure 2.10 A cross section through the culvert
The raw wastes will be disposed commencing from the side of the soil embankment. The waste loads from the vehicles will be tipped onto the engineered landfill. It will be filled up to the road embankment level. The bulldozer can be used to level and compact the wastes up to 800kg/m3 after allowing settlement for 10 days. However, a daily cover of compost will be used to ensure sanitary conditions. Once the total inclined heights between the embankments 469 m 476 m are achieved, re-circulation pipes will be laid and a cover made similar to the dumpsite and finally turf established. It will be an ongoing process until the engineered landfill is completed. The recycling regime based on the permeating rate will be used to control the head of above the liner. Whenever there is excess , the valve in the leading pipe connected to main conveyance pipe system will be opened. It is expected to have low BOD values, after three months of operation. In this instance, the will be directed through the second valve to the ASP reactor. The recirculation of enhances methane productions and the pipes will be interconnected to the gas extraction system network of the dumpsite. iii.
Capacity and life span of the landfill site
The capacity of the landfill is 100 days, filling at the rate of 120 tonnes/day. The total amount of filling is estimated at 12,000 tonnes. iv.
Equipment and structures to be used
collection pipes, stilling well made from reinforced concrete cylinders, recirculation pump and bulldozer or waste handler. v.
Initial soil requirement – source
The soil for the embankment, liner and cover will be from the site and clay deposits that are available at the site. The total quantities are given in Table 2.8. Table 2.8 Initial soil requirement 3
Soil Requirement
Quantity (m )
Bund Construction
120
Capping
390
Total
vi.
510
Post closure procedure
The gas extractions will last three years and it will be aerated and mined as explained in landfill bioreactor operations given in section (e) below. e. landfill bioreactors (LBRs) i.
Introduction
The classical landfill is an engineered land method to curtail and encase the solids wastes disposed in a manner that protects the environment. Within the landfill body, biological,
chemical and physical processes occur that promotes biodegradation of wastes. Polluting emissions of and gases needs careful design of landfills with the required barriers and treatment facilities. Inclusion of environmental barriers such as landfill liners and caps frequently excludes moisture that is essential to waste degradation. Consequently, wastes are contained and entombed in modern landfills and remains practically intact for long periods of time, possible in excess of the life of barriers (Reinhart et al., 2002). The waste degradation can be enhanced and accelerated within the life of barriers if the landfill is designed and operated as a bioreactor landfill. The bioreactor landfill provides control and process optimization, primarily through the addition of or other liquid amendments, if necessary. Thus, the bioreactor landfill attempts to control, monitor, and optimize the waste stabilization process rather than contain the wastes as prescribed by most regulations. It necessitated defining bioreactor landfills by a Solid Waste Association of North America working group as “a sanitary landfill operated for the purpose of transforming and stabilizing the readily and moderately decomposable organic wastes constituents within five to ten years following closure by purposeful control to enhance Microbiological processes. The bioreactor landfill significantly increases the extent of waste decomposition, conversion rates and process effectiveness over what would otherwise occur in a landfill”. Reinhart et al., 2002 states that there are four reasons generally cited as justification for bioreactor technology: (1) to increase the potential for waste to energy, (2) to store and to treat , (3) to recover air space, and (4) to ensure sustainability. The latter although not very well defined, points towards sustainable landfills with considerable cost benefits in reducing long term monitoring and maintenance and delayed sitting of new landfills. As long as outputs are controlled and acceptable way to prevent pollution, including residues left should not pose unacceptable environmental risks, thus the need for post closure care need not be passed on to the next generation and the future use of groundwater and other resources are not compromised. In order to make it more sustainable by reducing the time for biodegradation, Hettiarchchi et al., 2007, introduced the concept of biocells within the landfill bioreactor. In combining yet another concept of landfill mining or mechanical and biological treatment (MBT), the pretreated materials can be processed to produce RDF. Naturally, almost all of the wastes can be used to produce energy and power generation is a feasible option. In view of introducing such a technological approach, it was necessary to evaluate the problems encountered in developing landfill bioreactor with number of biocells for optimum conversion of wastes to landfill gas. ii. Technological brief
The research conducted at the University of Peradeniya entailed many aspects of MSW management. However, the focus was on developing sustainable landfills. Therefore, landfill simulations of lysimeter studies on open dumping, sanitary landfills, pretreated wastes on engineered landfills and landfill bioreactors were undertaken. There were number of landfill bioreactor lysimeter simulations. In each design, there were number of intervention to understand the processes taking place in landfills and landfill bioreactors. It was found that there were four major problems encountered in landfills and landfill bioreactors. They are;
1. Ammonia toxicity due to increasing in concentration with time when decomposition of organic materials takes place under anaerobic conditions. 2. Increasing in ion concentration due to decomposition of organic wastes leading to inhibition of reactions and eventually toxic conditions. 3. Breaching of high density polyethylene (HDPE) liners due to shear forces acting on the liner, particularly with cracks forming in clay cushion layers underneath the HDPE liner. It takes place with dehydration underneath the HDPE. High concentration of ion compounds, including heavy metals bound with organic substances is corrosive and thus, damages the liner systems. In the case of clay liners, they undergo rapid dispersions when the concentrations are high. 4. Inadequate good quality water (not direct recirculation of ) for anaerobic digestion to produce methane. Inability to breakdown coarse fibres due to lack of fresh water. In order to overcome these constraints in converting sanitary landfills to landfill bioreactors, external treatment is coupled to recirculation of high strength . It enables reduction of high ammonia and ion concentrations. The cost of treating the is one of the drawbacks in landfill bioreactors. The United States (US) environmental protection agency (EPA) prohibits use of external water supply, compelling recycling water for enhancing methane production, thus diluting the strength of the in the landfill body. Reinhart et al., 2002 in reporting the status and future gives the following summaries of expected performance of bioreactor landfills and lessons learnt from field scale bioreactor operations in Table 2.9 and 2.10below. Table 2.9 Objectives of field scale bioreactor operations N o
1 2 3 4 5 6 7 8 9 10 11 12
Objectives
Demonstrate accelerated landfill gas generation and biological stabilization while maximizing landfill gas capture Monitor biological conditions to optimize bioreactor process Landfill life extension through accelerated waste degradation Inform regulatory agencies Better understand movement of moisture Evaluate performance of shredded tires in LFG collection Achieve a 50% waste diversion goal Reduce usable gas extraction period to three years Reduce 6+ management costs Shorten time period required to put the site to a beneficial end use Evaluate performance of recirculation techniques Investigate the use of bioreactor to treat mechanically separated organic residue
Table 2.10 Lessons learned from field-scale bioreactor operations
No 1 2
3 4 5 6 7
Lessons learned Sealed system can result in plastic surface liners ballooning and tearing Rapid surface settlement can result in ponding Short circuiting occurs during recirculation, preventing achievement of field capacity for much of the landfill Continuous pumping of at two to three times the generation rate is necessary to avoid head on the liner build up A more permeable intermediate cover may be more efficient in rapidly reaching field capacity than recirculation Low permeability intermediate cover and heterogeneity of the waste leads to side seeps Accelerated gas production may lead to odors if not accommodated by aggressive LFG collection
8
infiltration and collection piping are vulnerable to irregular settling and clogging
9
Waste is less permeable than anticipated Increased condensate production led to short circuiting of moisture into landfill gas collection pipes
10 11 12 13
14
Storage must be provided to manage during wet weather periods Conversely, may not be sufficient in volume to completely wet waste, particularly for aerobic bioreactors Increased internal pore pressure due to high moisture content may lead to reduced factor of saf ety against slope stability and must be considered during the design process Channeling leads to immediate production, however long term recirculation increases uniform wetting and declining generation as the waste moisture content approaches field capacity
Eventually, a composite clay-waste polythene and clay liner and cover was conceived to function effectively and efficiently, a tropical landfill bioreactor with optimum anaerobic conditions for rapid methane production. iii. The process Phase of anaerobic digestion and permeability The lysimeter studies that led to the landfill bioreactor were important in identifying different physical and biochemical processes undergoing anaerobic decompositions. It was found that there are distinct reaction zones appearing inside the reactor. There exists moisture saturation layer below the surface and above the base of the landfill, dividing the reaction zones. These reactions zones promote different phases of anaerobic digestion processes, where the upper zone is hydrolysis and acidogenesis and acedogenesis and methanogenesis thriving in the lower zone. These zones get mixed with increased recirculation, causing toxic conditions, although the intention of recycling is to increase moisture contents in the upper layers of the landfill. At the same time recirculation create favourable pH for methanogenesis by buffering of excessive acidity in acidogenesis. Evidently, the needs treatment or dilution for upper zone reactions.
The success of the technology is due to the live biofilter liner system developed to make the system biologically stable, providing optimum conditions for anaerobic digestion. The construction of the clay polythene clay (CPC) liner system is with waste polyethylene sandwiched between clay soil layers. The bottom layer is first compacted and then a mixture of clay and waste polyethylene applied and again compacted. The top layer too is applied on the compacted waste polyethylene to a very high density. Once the composite liner system is constructed on the base and sides of the embankments, hydraulic conductivity of the liner is measured with a standing water head of at least one meter. The results of the Samanthurai experimentation on a test cell are shown in Figure 2.11. Both Peradeniya and Samanthurai landfill bioreactor test cells gave permeability values much less than internationally accepted standard of 1x10-7 cm/s and, making it a higher level of containment (Gunarathna et al., 2007 and Thivyatharsan et al., 2009). However, it is best to avoid total containment, since biological systems do require nutrient balancing. The use of HDPE liner causes desiccation of soil underneath and large cracks formed throughout the soil profile that leads to failure of most sanitary landfills. It is then necessary to impose the regulations and norms of keeping a safe distance of 500m from a water source, since it is a point source pollution from where HDPE liner breach. There will then be natural attenuation of the through the groundwater over 500m. However, the breaching needs to be attended to before saturation conditions develops, since there will be preferential paths leading to the nearest water source. These preferential paths exceed permeability limits as stated above.
Figure 2.11 Permeability of the field scale liner at hydraulic head of 86.2cm in saturated and unsaturated conditions
In the case of a live composite biofilter liner, it is not a point source discharge and the rate of percolation is less than the scientifically justifiable limit, and thus, natural attenuation is attained at steady state flow. In fact, in a live biofilter, the biochemical reactions reach equilibrium within the composite liner due to dissimilar materials of waste polyethylene and clay (Pathirana, 2008). Biochemical transformations of the take place in the liner to form water. Unlike HDPE or clay liners restricted to 300 mm of head for safety, the
composite liner can withstand higher pressures, thus providing adequate storage of for anaerobic digestion. Inhibitions and toxicity The sanitary landfill suffers from inherent inhibitory reactions due to high concentrations of ion compounds as reported by many authors. The action of recirculation causes these ion compounds to occupy active sites making the conditions toxic. The nitrogen initially taken up for cellular growth is released when these cells undergo premature death. The decaying cells and the biomass increases the concentration of ammonia, which eventually makes the anaerobic process toxic, through these inhibitory reactions. A number of supporting literature is available on ammonia toxicities in anaerobic digestion (Li et al., 1999). In the landfill bioreactor, the excess free ammonia gas is utilized in the live filter cover made from the same composite materials. It is kept above water saturation making the conditions ideal for replacing evaporating water with ammonia, which then are converted to ammonium cations or transformed to nitrite and nitrate. All of these nitrogen compounds constitute an excellent nitrogen source for the grass cover above the live biofilter cover. In most instances, the nitrite and nitrate leach down with rainfall and irrigation, whereas ammonia gets absorbed to soil particles. The availability of anommox bacterium even in small numbers can convert ammonia and nitrite to nitrogen, stated as,
2 NH NO N 4 2 2 2
The excess nitrate nitrogen washed down from the cover and solid wastes goes through the liner at a concentration of 30.1 ±1.9 mg/l. The nitrate leaves the biofilter after mineralizing the organic materials in terms of biomass and residual cellular materials. The mineralized compounds formed within the narrow passages and above the liner as solid phase reactions. These findings were from a leaching column study simulating the biofilter composite liner system (Pathirana, 2008). The mineralized depositions were examined and it was found to be similar in nature to fine clay deposits found in low lying lands, just at the interface between peat and peaty soil. In the lower profiles these clayey fractions “Kirimatta” crystallizes to form fine white sand. These were the observations that led to developing the liner system. emissions In an earlier study, it was pointed out that there are distinct phases and zones of reactions in landfills and dumpsites (Basnayake, 2008). At the beginning of the reactions, hydrolysis and acidogenesis occur in the upper zone and the products enter the zone below the saturation zone, separating the two major phases of reactions, causing those products as substrate to undergo acedogenesis and finally methanogenesis. The well stratified landfill body reduces the pollutant loads. Both the BOD and COD reduce rapidly with increase in rainwater entering the Cell, see Figure 2.6. The gradual reduction of these two parameters with precise recycling along with Total solids (TS), volatile solids(VS), total suspended solids (TSS), volatile
suspended solids (VSS) and total dissolved solids (TDS) indicated as illustrated in Figures 2.12 to 2.14 that non-inhibiting conditions seemed to have influenced the stability of the saturation zone. The dilutions were considerable since the water balance study indicated that rainfall contributions were 65% in supplying the upper zone with fresh water. The higher the moisture contents in this zone, the greater the production of substrate influencing the lower zone. The influence of the lower zone on the upper was discussed in terms of ammonia migration and leaching of nitrate to the lower zone.
70 l / 60 g ( n 50 o i t 40 a r t n 30 e c n 20 o C
TS VS
10 0 0
100
200
300
400
Time (days) Figure 2.12 Variation of TS and VS with time
35
TSS
l / 30 g ( n 25 o i t 20 a r t n 15 e c n 10 o C
VSS
5 0
0
100
200 Time (days)
Figure 2.13 Variation of TSS and VSS with time
300
400
16000 l / 14000 g m12000 ( n 10000 o i t a r 8000 t n 6000 e c n 4000 o C 2000 0
TDS
0
100
200
300
400
Time (days) Figure 2.14 Variation of TDS with time
Gas generations The top cover too certainly has had an effect on gas productions. Although, it allowed water to enter the cell, it also prevented gas from escaping since the cover was saturated in most instances with heavy rainfall experienced throughout the experimentation. It also prevented the cracking of the surface. With this passive sealing, the gas extractions were 2.8 l/min and it was augmented to 4.2 l/min with increase in suction pressure. The gas productions began very much earlier than reported (Alvarez, 2003), perhaps it is the fastest rate so far for landfill bioreactors/biocells. The methane gas generated from the Biocell can be used for secondary combustion to reduce and eliminate dioxins in the combusted fumes. This is a novel technique and it has been endorsed as the primary method to reduce filtration requirements to meet air quality standards (Basnayake, 2006). In the initial stages, the gas will be torched to satisfy the Cleaner Development Mechanism (CDM) project. Liner and cover integrity A 150 mm thick clay layer is unable to withstand high point loads, overburden and shearing forces that exceeds 10 kN/m2 /m high (Qian et.al., 2002). Therefore, one meter thick clay is prescribed as the standard not only for ensuring natural attenuation of permeating through the clay but also to overcome surcharge loads. The shear forces of the composite liner system can bear over ten times the loads compared to pure clay soils of equal thickness. The bearing capacity is much higher exhibiting greater plasticity due to enmeshed pieces of polythene. It is recommended to avoid point loads, thus travelling on the liner system is prohibitive. Therefore, disposal of one meter thick raw waste layer prior to travel is required to prevent point loads as expected from the wheels of compactor trucks. Also crawler tractors can rip the composite liner and should not be allowed without prior disposal of raw wastes above the liner system. Under very dry conditions clay cracks and it is a problem when dries up. In the case of liner left for long periods awaiting disposal of wastes, cracks and thus, allows wastes to fill up the cracks. The advantage of the composite liner system is that only the top clay
layer allows fragmented and small particles to enter small cracks, since the enmeshed polyethylene layers prevents further movements of such materials. Also the cracks are very much smaller since the depths of the cracks are restricted and constrained with polyethylene sheets. Under waterlogged conditions, the consistency of clay reach liquid limits and beyond it dispersion takes place, but with polyethylene sheets they are held together, even at very high moisture contents without being dispersed. It is evident from the results shown by Terzaghi and Peck, (1967) given in Figure 2.15 that moisture contents within the composite liner remains less than 89% moisture content and thus, exhibits cohesive and adhesive strengths. The adhesive strengths are much higher than soils with high clay contents. However, the strength of the composite liner is low relative to low moisture consistency states, see Figure 2.15. Therefore, initial loading should be done under dry conditions. When the water table rises, the water pressure on the liner is compensated with an equal and opposite force from the . It is very apparent that the damage to the liner can be prevented and could be used under both wet and dry conditions. In fact, it is the minimum risk in comparison to HDPE or only clay liners. Similarly the composite cover with a final soil layer makes the system more natural with high content of water absorbed from rainfall or irrigation. As long as the surface is wet, it is gas tight and the composite cover and soil layer will not crack. The comparisons of liner systems and landfill types, namely between conventional landfill gas (LFG) and LBR are given in Tables 2.11 and 2.12.
Figure 2.15 Rupture lines for undrained test on a lean clay, in terms of total st resses, at various initial degrees of saturation. Table 2.11 The strength and weakness analysis of liner systems
No
1 2
3
4
5
6
7
8 9 10 11
12
13
Reported problems
Ballooning and tearing Rapid surface settlement can result in ponding Short circuiting of leachate recirculation, preventing FC achievement of field capacity for much of the landfill Continuous pumping of leachate at two to three times the generation rate is necessary to avoid head on the liner build up A more permeable intermediate cover may be more efficient in rapidly reaching field capacity than leachate recirculation Low permeability intermediate cover and heterogeneity of the waste leads to side seeps Accelerated gas production may lead to odors if not accommodated by aggressive LFG collection Leachate infiltration and collection piping are vulnerable to irregular settling and clogging Waste is less permeable than anticipated Increased condensate production led to short circuiting of moisture into landfill gas collection pipes Storage must be provided to manage leachate during wet weather periods Conversely, leachate may not be sufficient in volume to completely wet waste, particularly for aerobic bioreactors Increased internal pore pressure due to high moisture content may lead to reduced factor of safety against slope stability and must be considered during the design process
HDPE
Clay
Composite
Frequent
none
none
Frequent
Likely
Less likely
Limited quantity
Limited quantity
Unlimited quantity
Limited quantity
Limited quantity
Unlimited quantity
Compost
Compost
Compost
Less
More
More
Less
More
Much more
Very vulnerable
Very vulnerable
Less vulnerable
Less, low degradation
Less, Low degradation
More, High degradation
Less
Less
More
Yes
Yes
No
Inadequate
Inadequate
Adequate
Unsafe
Unsafe
Safe
Table 2.12 The strength and weakness analysis of conventional LFG and LBR No
Measurable output
1.0
Life of landfill
2.0
Conventional LFG
LBR
Long duration
Very short duration
Onset of gas productions
Long
Very short
3.0
Gas generation rate
Low
High
4.0
Gas fluctuations and ceasing
High
Low/controlled
5.0
head
Low
High/composite liner
6.0
Average strength
High
Low
7.0
Regular Maintenance
Low
High
8.0
Duration of Maintenance
High
Low
9.0
Sustainability (landfill footprint)
Large
Small
Sustainable landfills The estimated gas generations are three years and after the gas ceases, the biocell is aerated to oxidize and remove odorous compounds. The pipes are used to aerate the body of cells. The excavation is done by slicing through the profile as shown in Plate 2.3. It is important to carefully remove the cover consisting of grass and composite liner. These two components should be removed separately, so that they could be reutilized. The remaining materials are excavated, and heaped up in rows for ten days and at least one turning of the piles is required to dry and completely digest rapid biodegradable wastes. The material is then scooped and raked to remove large particles. The small particles and waste polyethylene is sent through a screening machine to separate polyethylene and digested biodegradable matter. The latter is sold as grade II compost and the wasted polyethylene made into pellets and sold as RDF to envisaged power plants in the future. Since the power plant is in close proximity to the power plant within the disposal facility, the dried excavated wastes need not be further processed before feeding the gasifier. It is reported that RDF manufacture is costly, if the raw wastes are processed to produce RDF as reported by UNEP, 2010 Instead the RDF manufactured from residual wastes derived
from excavated wastes by mining landfills is cost effective and technically feasible, since the calorific value is even higher than coal (Ecotech Lanka, 2010). There are many publications Prechthai et al., 2006; SmellWell, 2010 to justify the use of RDF produced from mined wastes
Plate 2.3 Slicing through the landfill bioreactor profile
The dual fuel system as against direct use of LFG in internal combustion (IC) engines is better for the following reasons. a. b. c. d. e. f.
The gas need not be very clean, since combustors can burn mixture of gases, unlike IC engines. The efficiencies of steam turbine systems are much higher than IC engines. In the event of reduction in gas productions, RDF component can be increased, thus consistent production of energy. The reliability of producing power is higher with a dual fuel system with less maintenance There will be less dioxin productions with dual fuel. The polyethylene component can be combusted safely
There are many RDF plants, not necessarily made for mined wastes that can be used with dual fuel system, thus making the system more robust and risk aversive. The average capital costs are within US$ 1.5 to 1.7 for generating 1MW (Ref. curtailed for confidentiality).The unusable material is disposed of in a residual landfill having the same composite liner. The next important operation is to rehabilitate the cleared biocell, preparing for disposing once again of raw wastes. iv. Capacity and life span of the landfill bioreactors (number, capacity, & lifespan of each bioreactor
The Landfill Bioreactor (LBR-1) as shown in Figure 2.16 and Annexure will have a capacity of 64800 tonnes. It will be 2 meters below ground and 8 meters above. It will have a life span of 1.5 years. The LBR-2 will be constructed, once the squatters are
relocated. It should be constructed and operational before post closure of LBR-1. The expected life of LBR-2 is two years. In both of the LBRs, the embankments will be constructed to take the total load with with 1.5 meter meter head. In each of the LBRs, number of biocells will be constructed. Each biocell is filled for a period of three months, since gas generations are much quicker than conventional LBRs.
e l w n o i a t c x r t e a s G h a t r e d e a t p c m o C n t e m k n a b m e
R 1 - B R
X
X
e l w g n i l i t e s a h t a e c L
N A L P
e p p i n o i t e c o l c a s G e l w n o i t a c r x t e a s G n o a i t u l c r i e c e r a t h a c e L h t e r d e t a c p m o C k o r w e t n e p p i a n e t m k n a b m e
m e t y s n s o a i t u l c r e i c e r a t h a e c L m 0 . 6 m 0 . 2
L G
m 5 . 2
e l w n o i t e c l o e c a h t a c e L e p p i h n e c r d t e l i f e v l a g r d n a
W M S d e t a c p m o C ) m ³ g / k 0 8 ( X - X N O T I C E S
Figure 2.16 Landfill bioreactor (LBR-I)
v. Equipments and structures to be used The construction details of the landfill bioreactor are given in Annexure……The equipments used for construction are; Excavator, Dozer, Hand held plate or roller vibrator compactor Pumps Redevelopment of roads Fencing, gates and retaining walls Liner and capping systems
wells, collection pipes and recirculation system vi Details of all inputs, outputs of the process and by products including material and energy balance sheets
The composition of the wastes disposed in the LFB will differ and depends on the amount of wastes being recycled. Although recycling is encouraged, LCA points towards limited recycle use of plastics and the maximum number of recycling events is one, since the quality becomes very poor if the number of events increases. However, there will be a progressive increase in recycling plastics. The pie charts (Figures 2.3 and 2.17) illustrate the average composition of wastes collected in Kandy and mined from the Gohagoda dumpsite. The flow diagram (Figure 2.18) shows the inputs and outputs of the integrated system.
Figure 2.17 Average composition of mined waste from gohagoda dumpsite
CH4 Landfill bioreactor
Dumpsite WTE Plant
Raw Wastes
Mine & Sorter
120 TPD MRF
Electricity to National grid
RDF processing Plant
10 MW Ash Recyclables
C&D Wastes
Block Manufacture
Figure 2.18 Inputs and outputs of the integrated solid waste management system
The mass and energy balances of the LBR Test Cell are given in Annexure…… The mass balance is also summarized in the Tables 2.13 and 2.14 for one tonne of wastes. The ratio of ash content was used to deduce the total decomposition, since the initial quantum remains the same. Thus the ratio gives the actual amount decomposed. The volatile content of samples before after loading and mining the test cell were experimentally obtained. The amount of carbon were determined based on C content = VS/1.8. Therefore, the actual losses of dry materials, volatile solids and carbon were 36%, 48% and 51% respectively. Also the mass balance calculations were based on the captured gas of methane and carbon dioxide given in Table 2.14. The total gas generations were 22% of the raw wastes on dry basis. The and permeate are accounted in the losses and notably very small, given in Tables2.15, 2.16 In fact, the recycling of reduced the quantity to be discharged. Nevertheless, almost 13kg of carbon, notably 5.25% cannot be accounted. It could very well be retaining in the mined wastes, since there could be considerable error in the determining volatile content in wastes and the error could be as much as 12%. The energy balance study shows a loss of 32% from experimental values obtained from Manitkpura et al, 2010 and Nimalan 2010 as given in Table 2.17. Almost one third of the energy content is lost to the atmosphere and small quantity as . Methane emissions from the test cell were calculated based on the extraction rate of 4.2l/min for the 52 tonnes disposed, refer to Table 2.18. The energy content per tonne of wastes in Table 2.19 is slightly above than reported value of Manikpura et al., 2010. Table 2.13 Mass Balance for one tonne of wastes before and after mining of Test Cel l Type of material 1 Combustible raw Wastes 2 Non Combustible Total
wb db VS 961.33 468.96 423.23 38.67 8.43 1000.00 477.39
3 Combustible mined wastes 4 Non Combustibles Total Average Ratio 5 Deduced Qty of mined
949.86 574.29 364.08 210.21 50.14 7.37 1000.00 581.66 0.22 192.76 114.04
63.35
105.52 105.52 170.67 203.67 468.96 423.23 36.39 48.12
54.83 125.95 244.14 51.59
6 Gas 7 Losses Mass balance 5+6+7 % loss
Ash C content 45.73 244.14
45.73
Note: Carbon content calculated VS/1.8 = C, 203.67/18=113.15, thus unaccountable 12.81 kg losses include small quantities of leachate and permeate as tables 2.15 and 2.16
Table 2.14 Mass balance of methane extraction from Test cell Description
CH4
60 40 16 44 0.71 1.96 kg/m3 42.86 78.57 kg 0.35 0.65 1 2.52 1.68 l/min 3629 2419 l/day 1,324,512 883,008 l/year 1,325 883 m3 /year 3,974 2,649 m3 2,838 2,649 kg 2.65 tonnes 2.84 0.0546 0.0509 kg/tonnes 54.58 50.94 kg 2.13 0.72 tonnes 0.04 0.01 kg/tonne 40.94 13.89 kg
Volume % mol. wt
Extraction rate
Mass of extraction for 52 T
Mass of extraction for 1 tonne Carbon extracted for 50 T Carbon extracted for I tonne
unit
CO2
Density Mass % mass 4.20 6048 2,207,520 2,208 6,623 5,487 5.49 0.1055 105.52 2.85 0.05 54.83
Table 2.15: Mass of materials removed with Description
TS
VS
Ash
Average concentration of removed
25.10
14.42
12.24
g/l
Quantity of removed
4,736
4,736
4,736
l
118,890 68,273 57,974
g
Mass of
118.89
68.27
57.97
kg
2.29
1.31
1.11
kg/tonne
Table 2.16 Mass of materials permeated
unit
Description
Liner permeability
1.00E-07
cm/s
35
m2
Rate of permeation
3.50E-08
m3 /s
Time duration for 3 years
9.46E+07
s
3.31128
m3
Average total solids
12.24
g/l
Total solids removed for 52 tonnes
40.53
kg
Total surface area
Total volume permeate
Unit of solids removed
unit
0.78 kg/tonne
Table 2.17 Energy balance per tonne of wastes in kJ for Test Cell
Category Experimental Modified Shafizadeh 9,585,164 Raw waste 3,460,514 3,870,456 Mined waste 3,030,128 Gas 3,094,522 2,684,580 Loss
% of Raw waste 36.10 31.61 32.28
Table 2.18 The HHV of the methane gas extracted from one tonne of wastes Description Value Units Calorific value 212.5 kcal/mole 13.28 kcal/g 55,515.63 kJ/kg CH4 for 52 T 2.84 Tonnes per 3 years Total energy generated 157,566,668 kJ per 3 years CH4 for one tonne kJ per 3 years 3,030,128 Table 2.19 Predicted Energy balance per tonne of wastes in kJ Category Experimental Predicted 9,585,164 9,585,164 Raw 3,460,514 3,460,514 Mined 3,030,128 4,328,755 Gas 3,094,522 1,795,896 Loss % loss 32 19 f. landfill gas extraction from LBRs and power generation from extracted gas i. Gas extraction system including anticipated quantity and quality
The expected quantity of gas extraction is given in Table 2.20 and mass balance of methane extractions given in Table 2.21. It is very likely in large scale applications to increase the extractions which will reduce the losses to 19% from 32% as stated in Table 2.19. A network of staggered arrangement of extraction wells will be installed as shown in Figure 2.19 and a single well shown in Figure 2.20. Table 2.20 Predictions of HHV of the methane gas extraction in the proposed system Description Value Units Calorific value 212.5 kcal/mole 13.28 kcal/g 55,515.63 kJ/kg CH4 for 52 T 4.05 tonnes per 3 years Total energy generated 225,095,239 kJ per 3 years CH4 for one tonne kJ per 3 years 4,328,755
Figure 2.19 A network of staggered arrangement of extraction wells.
Figure 2.20 A gas extraction well
Table 2.21 Mass balance of predicted methane extraction from LFBs and dumpsite Description
Extraction rate
Mass of extraction for 52 T
Mass of extraction for I MT Carbon extracted for 50 T Carbon extracted for 1 MT ii.
CH4
60 Volume % 16 mol. wt 0.71 Density 42.86 Mass 0.35 % mass 3.60 6.00 8640 5184 3,153,600 1,892,160 3154 1892 5676 9461 7839 4055 7.84 4.05 0.1507 0.0780 77.97 150.75 4.07 3.04 0.08 0.06 58.48 78.33
CO2
40 44 1.96 78.57 0.65 2.40 3456 1,261,440 1261 3784 3784 3.78 0.0728 72.78 1.03 0.02 19.85
unit percent by vol.
kg/m3 1 l/min l/day l/year m3/year m3 kg tonnes kg/tonnes kg tonnes kg/tonne kg
Gas cleaning system
The landfill gas cleaning system will have a combination of filtering systems as shown in following figure 2.21.
Figure 2.21 Gas cleaning system for power plant
iii.
Installation of power plant and power generation equipments and process
In the initial stages a test generator system will be operated and then to supply the gas for the dual fuel RDF thermal power plants. g. Installation of RDF plant and mining of dumpsite i.
Mining of dumpsite and RDF manufacturing procedure
Once the first LBR is constructed, the dumpsite will be capped and then gas extracted and flared. The torch to flare the LFG is shown in Figure 2.22. It will be flared or a small generator will be operated until the thermal power is commissioned. On the Southern side, a three month mining capacity will be demarcated with drains cut such that is drained or pumped to ensure dry conditions in the isolated cell for mining. These cells will be constructed and mined progressively working inwards of the dumpsite while gas is extracted from the other parts of the dump. The working face of the dump will be aerated and odour filter installed and operated with temporary shelter for both the filter and working face. The shelter will house the sorting and separation machinery for screening and manufacture of RDF.
Figure 2.22 The torch to flare the LFG ii. expected calorific value of RDF
The Table 2.22 gives the experimental calorific values of the RDF expected from the dumpsite. They are highly degraded samples and could be considered as the worse scenario. In contrast, Table 2.22 gives values for the LBR in the future LBR.
Table 2.22: Experimental and predicted energy values for the mined wastes from Gohagoda dumpsite (samples from surface) Gohagoda Mined Waste Mined Waste Exp Category kg in kg in VS C in Mod.Sha Energy Mod.Sha C% HHV wb db kg kg (kJ/kg) Cont. (kJ) (kJ) (kJ/kg)
Coconut husk Coconut shells Paper Biodegradable Wood Leather Textile Plastics Polythene Rubber Mixed Materials Health hazard materials Sub total Scrap metal Batteries & electronic parts Construction demolitions Glass Ceramic Sub total
3.77 3.19 2.23 0.39 1.70 0.81 2.14 9.81 22.36 1.02 35.12 2.19 84.72
1.10 0.61 2.06 1.92 0.71 0.62 0.19 0.06 0.69 0.56 0.40 0.32 1.07 1.01 7.73 7.63 5.19 1.19 0.83 0.81 15.78 4.70 1.77 37.52 19.44
0.77
0.50 18.08
0.28
0.28
6.66 4.78 2.79 15.28
6.30 4.58 2.21 13.86
0.341 1.065 0.345 0.031 0.312 0.180 0.563 4.238 0.663 0.449 2.611 10.80
31.111 51.667 48.889 16.667 45.000 44.444 52.778 54.833 12.778 54.472 16.549
17200.000 17200.000 27470.000 24563.585 16400.000 14000.000 11531.019 45000.000 33300.000 25500.000 22578.090
15560.033 19617.700 19069.367 12708.700 18301.700 18192.033 11531.019 45000.000 33300.000 25500.000 22578.090
15093.133 28359.001 15501.774 3695.965 9090.733 4532.233 9847.450 278245.922 138323.265 16831.603 285018.792
17067.562 40431.568 13451.448 2390.272 12681.087 7361.655 12309.313 347807.402 172904.081 21039.503 356273.490
804539.8708
1003717.381
Total
100.00
51.38
iii. Equipment and structures to be used
The envisaged system will require the following equipment and structures. 1. Excavator 2. Moveable shelter for RDF manufacturing. 3. Sorting and screening machines and equipment (convey belts etc.) 4. Shredder 5. Mixer 6. Gas storage tank. iv. initial power requirement – source and capacity
The LFG will be stored in tanks and used for initial start-up. v. Power generation using RDF
There are number of different power plants in the world. Most of them are incinerators rather than power generation systems. Although they produce electricity, the primary task is to incinerate as much as possible large quantities of wastes generated in highly urbanized cities. All of them are dependent on the tipping fee (disposal fee) for generating profits and tariff for electricity productions are so low that it is not economically feasible to make business sense in generating power. Therefore, the systems efficiencies are within the range of 15 to 25%. However, RDF plants, particularly in Germany and France reach 40%. In this study, it was finally decided to be very conservative and calculate on the basis of 33%, although gas is also available for secondary combustion, thus augmenting thermal conversion efficiency of the boiler to generate super steam. In this instance, the thermal conversion efficiency will increase to 40% or more. It is proposed to in the first instance to install and operate a 5MW plant and then install another 5MW or less if other sources of energy are available on contract. The plausible sources are MSW from other local authorities, saw dust and plastics that cannot be recycled. The quantity to be sourced will depend on the thermal conversion efficiencies of the first 5MW plant and the quantity of wastes available in the dumpsite. It is estimated to be 196,309 tonnes, see Table 2.23. The Figure 2.23 below show the duration of mining depending on the rate of excavation and Table X10 gives the options and transition between dumpsite mining and LBR mining for 5MW and 10MW. There are number of power plants being examined. They are; 1. 2. 3.
stoker grate, rotary kiln and pyrolyser/gasifier
Table 2.23 the estimation of available quantity of MSW in the dumpsite Disposal Residual Predicted Year Tonnes/day Tonnes Fraction Total Tonnes 1970 55 1980 67 200,750 0.12214 24519.66 1990 82 244,713 0.149182 36506.91 2000 100 298,304 0.182212 54354.52 2010 121 363,631 0.222554 80927.53 2020 148 443,264 2030 180 540336 2040 200 657000 Total 196,309
250
y = 364.16e-0.235x R2 = 0.9827
200
D P T e 150 t a r g i 100 n n i M
Series1 Expon. (Series1)
50 0
0
2
4
6
8
years
Figure 2.23 Mining rate as a function of required duration of dumpsite life
Electrical System In theoretical terms, the electric power system at Gohagoda will comprise of four main components. These are as follows: 1. Electric power generating plant (10-MW) 2. Switchyard inclusive of power conditioners, SCADA, safety devises and step-up transformer 3. Transmission line from power plant to the Grid Interconnection Point 4. Grid Interconnection Point and Existing (National) Transmission Line The design and installation of components itemized 1 – 3 above are under the direct purview of the promoter company Ecotech Lanka Limited while the intake of power from the site into the national grid – itemized 4 above - falls under the purview of the national power utility, the Ceylon Electricity Board (CEB). Considering the nature and its importance to the proposed 10 MW Power plant, this chapter will be dedicated to describing design details of components 1 – 3. Component 4 merits some mention as it
forms the link between the project and the national electric grid. The main characteristics of the proposal are summarised in Table 2.24 below. Table 2.24 Main characteristics of the proposed power project General Life of project Approximately 25 years Generation capacity Approximately 10 megawatts Vegetation clearing Not more than 4 acres for proposal site, easement for power line for power plant and easement for water pipeline. Water requirement Not more than 10 mega liters per year Fuel Fuel quantity Not more than 40,000 tonnes per annum Fuel type Methane from Land-fill Bio Reactor, Gas and RDF from Dump Site Fuel storage Plant is located within the Dump Site Boundary. Main plant equipment Combustion system Fluidized bed combustion boiler with flue gas recirculation and over fire air systems Particulate emission baghouses fitted with fabric bags control system Stack height Not more than 30 meters Cooling system Air-cooled condenser Misc Ash storage Maximum of 100 tonnes on site stored in enclosed containers. Other arrangements made to store excess ash.
Electric Power Generating Plant There will be a 10 megawatt (10-MWe) electrical power system installed at the dumpsite utilizing waste material to generate electricity to be delivered to the national electrical grid of the Ceylon Electricity Board (CEB). The proposed method is based on a dual-fuel system, which is a gasifier technology coupled to a steam turbine. Methane produced from the dump through the bio-reactors will be burnt under controlled conditions to produce producer gas which is sent to a furnace that also takes in solid fuel (RDF); the multi-fuel burning process produces heat sufficient to generate super-heated steam that is in turn utilized to operate a condensing (steam) turbine based on a Rankine cycle. There have been many advances made in the gasification area globally, in which state of the art gasifiers, aided by recent developments in fluidised bed technologies – are making a come back in power generating scenarios when the single operation of a Rankine type power plant is itself not feasible or would only yield lower energy conversion percentages. A gasification technology coupled to a conventional Rankine cycle power plant would allow electricity generation at an enhanced rate. This typically brings in a high efficiency of energy conversion. Under this system (also known as the so-called BIG/GT technologies – Biomass Integrated Gasification and Turbines), a condensing steam turbine will be used with a fluidized bed or other gasifier in a typical MSW application for power generation. Gasification (initially) to capture a fluidized fuel state for both solid and near-
solid fuel has been successfully demonstrated in related biomass industries such as in bagasse based power generation. The lower use of steam as opposed to primary cycle, steam based power generation is a noteworthy and desirable feature in the use of a gasifier. Figure 2.24 shows a simplified, generic layout of a BIG/GT system that is also proposed for the Gohagoda MSW Project. This system includes a fluidized gasifier, equipment that transforms methane gas from bio-reactors in the dump site and solid fuel (RDF) into a low calorific value gas through a high temperature conversion process. Fuel gas from the dump site contains particulates, tar, alkaline metals and other compounds that could affect the steam turbine operation. Thus, before introducing the fuel gas into the turbine combustion chamber, it needs to pass through a cleaning filter.
Recuperative boiler Technological process
Figure 2.24 Simplified scheme of a BIG/GT system
For descriptive purposes, a steam turbine is a thermodynamic device that converts the energy in high-pressure, high-temperature steam into shaft power that can in turn be used to turn a generator and produce electric power. A steam turbine requires a separate heat source and does not directly convert fuel to electric energy. The energy is transferred from the boiler to the turbine through high-pressure steam, which in turn powers the turbine and generator. This separation of functions enables steam turbines to operate with an enormous variety of fuels, from natural gas to solid waste, including coal, wood, wood waste, agricultural byproducts and even with municipality solid waste. In the thermodynamic cycle illustrated in Figure shown below, called the Rankine cycle, liquid water is converted to high-pressure steam in the boiler and fed into the steam turbine. The steam causes the turbine blades to rotate, creating power that is turned into electricity with a generator. A condenser and pump are used to collect the steam exiting
the turbine, feeding it into the boiler and completing the cycle. There are several different types of steam turbines: 1) A condensing steam turbine as shown in the Figure 2.25 is for power-only applications and expands the pressurized steam to low pressure at which point a steam/liquid water mixture is exhausted to a condenser at vacuum conditions.
Figure 2.25 A condensing steam turbine
The turbine exhaust gases have a temperature of approximately 500°C and they still can constitute a source of heat for steam generation in a recuperative boiler, and that could be used in a cycle with steam turbines. Typically in the steam combined cycle there is a topping section with a Brayton cycle (I), and a bottoming section, that uses the heat rejected by the Brayton cycle as its source, constituted by a Rankine cycle with a steam turbine (II). This “in cascade” use (conversion) of the heat makes the efficiency of this combined cycle higher than that of pure and conventional steam cycles. In essence, gasification provides a means to convert methane and other gases generated under controlled conditions into fuel gas through its partial oxidation at high temperatures. This gas, also known as producer gas, is an intermediate fuel, and it will be able to be further employed on another conversion process – aided by the RDF (residue derived fuel), gotten from the dumpsite - in order to generate heat or mechanical power, fitting itself to systems where solid waste material alone cannot be used. Basically, the average content of the combustible components in the gas resulting from biomass is: CO between 10 and 15%, H2 between 15 and 20% and CH4 between 3 and 5%. The main project facilities comprise multi-fuel fired two 5-MW steam turbine based power modules, a power house and auxiliary facilities that include a switch yard, raw water reservoir, water pre-treatment system, de-mineralization plant, cooling water pump house, fuel handling system, ash handling and disposal system, and a residential facility for the power plant staff. The break-up of the power plant into other different configurations, such as initially a 2.5-MW module to be supplemented by a 7.5-MW
module or, the installation of a complete 10-MW power plant in the first instance is a possibility but this will not affect the generic description here involving the upper limit of the power capacity for the site, that is, 10-MW. Each of the power modules will have a fluidized bed gasifier, high pressure steam boiler, turbine and generator, and a condensate recovery system along with auxiliary parts. The steam that passes through each turbine is partly condensed into water that allows the steam to expand so that the turbine can extract most of the energy from the steam. This allows the steam to expand more and helps the turbine extract the maximum energy from it, making the electricity generating process much more efficient. Each boiler unit will have a multi-fuel furnace, regenerative type air heater, forced draft (FD) fan, and induced draft (ID) fan. Each will have steam conditions of about 25 mega-pascals (MPa)/571 °C for main steam and 569 °C for re-heated steam. Low oxides of nitrogen (NOx) burners will be used. The main plant comprises of three inter-connected structures: (i) Boiler Structures (ii) Turbine Building (iii) An integrated Control and Operational Building. The following are some other salient features of the power plant: Electrostatic precipitators: Each steam generating unit will be fitted with an electrostatic precipitator (ESP) with parallel exhaust gas paths. Each path will consist of a number of fields or the collection of fly ash. The ESP‟s will have a dust collection efficiency of not less than 99% while firing with solid fuel (RDF) with the highest ash content (estimated at about 34%). Flue Gas De-sulfurization units: Each generating unit will have one limestone based desulfurization unit, including a booster fan, de-aerating fans, two to three slurry decirculation pumps, one-absorber tower, one emergency slurry tank (for both units), and two air-compressors (for both units). Fuel Handling System: The Fuel handling system, (FHS) will comprise of two fuel streams into each power plant, and in the case of RDF, one operating conveyer and one standby conveyer. The complete FHS will be designed for the simultaneous entry of both fuels, namely producer gas and RDF. Cooling Water System: The power plant will have a closed-circuit cooling water system using water from the Mahaweli River. The project‟s total cooling water system is estimated at about 150 cubic meters per day. The make-up water requirement is estimated to be 25 cubic meters per day. Water Treatment System: Water to be used in power plant operations will be filtered and de-mineralized before use.
vi. offsite disposal of RDF
In the event of sourcing funds for a power plant or there is excess of RDF, it is possible to sell it at the same price as coal for Norochcholai coal power plant, since the GCV/HHV of RDF found in the dumpsite and predicted RDF from LFB is more than coal. Also some of the organic residual materials like coconut shells, husk and the like can be sold to tea estates or converted to biochar for marketing the product as fertilizer. h. Power transmission system
i.
Transmission system, switch yard connections
The Switchyard will form an integral part the 10-MW MSW (Biomass) power plant. The main integral controls for the key equipment, namely, the Boiler, Turbine and generator as well as the SCADA system shall constitute the switchyard and control system. True unification will be achieved by incorporating or integrating switchyard controls (SCADA). The Supervisory control and data acquisition system (SCADA) of switchyard consists of Operator Stations, Engineer's Observation Station, Historical Data Logger, Computers and associated peripherals and the switchyard bay control systems interconnected through a high speed network . The system constitutes several operator work stations and engineer's work station with a high resolution Color display monitor. The switchyard shall comprise of air-insulated aluminous bus type suitable for medium scale current uptakes. Each circuit breaker shall comprise of a no-load breaker, airinsulated, disconnect switch on each side. An isolating switch is connected to each generator transformer connection to the main bus. Current and Voltage transformers are located at points within the switchyard to provide for metering and relaying. Control, protection and monitoring for the switchyard will be located in the switchyard relay room of the electrical building. All protection and circuit breaker controls will be powered from the station battery-backed 220V DC system. A grounding grid is provided to control step and touch potentials. Lightning protection will be provided by shield wires for overhead lines through appropriately sized Lightning arrestors. The communication between the facility switchyard and the control building will be facilitated through an internal telecommunications system. Revenue metering is provided on the outgoing lines, recording net power from the switchyard. Upgrading transformer will be installed before the metering side. The standard upgrade conversion of 440-volts to 33-kV transformer will be available at the point of installation. The following specifications for the step-up transformer are currently available: 3 phase, 50-60 Hz, 33kV high voltage winding and 440V low voltage winding. The transformer will be sourced locally or otherwise, depending on price and availability, and conformity with specifications. The switchyard and the transformation system will be certified by either a CEB-supervised independent verification process, carried out by a chartered engineer.
ii. grid substations The Grid substation as proposed by the CEB is at Kiribathkumbura. Folowing figure 2.26 shows the proposal issued with the Letter of Intent (LOI) by the CEB.
Figure 2.26 Grid substation as proposed by CEB iii. details of power distribution
Transmission line from power plant to the Grid Interconnection Point The following descri ption is based on the CEB‟s distribution condition as of January 2011. Power Line: Approximately 10-km long SC-LYNX Tower 33 kV line will be constructed at the expense of the project to the nearest interconnection point. The interconnection point is identified as Kiribathkumbura GSS (Grid Sub-Station). Load Breaker Switch (LBS): One number of SF6 LBS – with remote control capability will be installed at the power plant before the energy meters and the 33-kV tower line will be directly connected to the DSS through a separate 33-kV Distribution Bay. Metering Equipment: AS noted above, metering equipment will be installed within power house premises. The layout diagram below Figure 2.27 (courtesy: the CEB) illustrates the gridinterconnection transmission line from the Gohagoda Site to the Kiribathkumbura DSS while the single line diagram further below illustrates the entire power plant and the DSS connection point in more detail along with other electrical structures and networks within the boundary of the power plant.
Figure 2.27 Layout of Transmission line from power plant to the Grid Interconnection Point
iv. safety devices
i. collection and treatment system i.
generation points, collection and treatment methods
The EIA team spent considerable time and effort in finding the surface and subsurface flow of . In order quantify number of rainfall storm events have been recorded at site and also physically observed the transportation and the noted number of points the oozing out from embankments. The pipes that had been laid in 2005 were intact, but had not functioned as intended. The network of new pipes and the drainage system is given in Figure 2.28. The wells that were examined for water quality has been marked on the Figure 3.13 in section 3.35. In most deep percolations of subsurface flows, in most parts of the dump, there seems to be natural attenuation. However, an interceptor drain around the dump has been installed to capture all of subsurface flows in the upper strata that normally discharge into surface flow streams at different points in the dumpsite. On the far North East side of the dump, it is best to pump the excess into the nearest pipe network points. It is strongly recommended to relocate the piggeries to prevent additional pollution loads on the surface streams leading to the river. The Hydrological Evaluation of Landfill Performance (HELP) model was used in estimating the total discharges as reported by Manikpura et al., 2008. In addition, the discharges were measured during low and heavy rainfall events. According to Manikpura et al., 2008 the total estimated discharge is 30,304 m3 /year. The contribution to formation is 24% of the total rainfall on average received per year. The highest storage requirement can be calculated based on a peak rainfall event of 400 mm at Gohagoda. The primary treatment is in an anaerobic Treatment Bioreactor (LTB) and the design criteria and deductions are given in Table 2.25. It has been shown that old LBR perform extremely well in breaking down high strength , thus reducing to less than 500 mg/l or even less values to 250 mg/l. In the process of mineralization in the liner system, the COD is reduced to 1500 mg/l and as the required solid retention time (SRT) is achieved, it can even reach 800 mg/l.
Figure 2.28 The network of new pipes and the drainage system
Table X11 2.25 Treatment Bioreactor (LTB) and the design criteria and deductions Once the is removed from an anaerobic environment, considerable odour nuisance is created. In order to lessen this effect, an aerobic biofilter system will be used. If the need arise to incorporate a gas cleaning system, the wet and dry media biofilter developed by Ariyawansha et al., 2009 can be incorporated to negate odour emissions. In the next stage of treatment, an activated Sludge Process (ASP) will be installed and operated with chemical treatment for settlement in the clarifying tank. The entire process flow diagram is given in Figure 2.29.
Figure 2.29 The entire process flow diagram ii. Treated effluent disposal systems
Finally the treated water will be sent trough the constructed wetland and then discharged into the main water course. The cross section of the constructed wetland and the layout design is given in Annexure…..or figure 2.30
Figure 2.30 The cross section of the constructed wetland and the layout design j. cooling water treatment process
There are two options for condensing the steam for a closed loop system with 10 to 15% losses. The latest being fin type air condensers and the other water condensers and water towers for cooling the water to ambient temperatures. The advantage of using air as the media has both the effects of condensing the water while providing directly the hot air for reducing the moisture content of the RDF. Otherwise a closed loop system of water is required for the condenser too with an additional heat exchanger with air to make use of hot air for drying RDF to very low moisture contents. There is yet another option of using ground source cooling of slightly above ambient water coming out of the initial cooling to reduce the temperature to 20oC. The use of heat pumps is another option rather than increasing the water temperature of the river. The river water can be used but it should be the last option. The water looses can be as much as 100 to 150 m3 /day if the system has problems of condensing. Therefore, a water treatment plant is required to ensure Si content to be less than 5 microgram/L and hardness zero. k. inert material disposal system
It is envisaged to produce textile fibre C&D waste cement blocks with SLS standards building material, stemming from a recent study by Jayasinghe et al., 2009. Materials like PVC, inert in nature at ambient temperatures will be used for making these building blocks. The large PVC pieces will be size reduced to small aggregate sizes. Furthermore, ceramic and glass either could be used in these cement blocks or used for paving in roads. There is a very high demand for scrap metal, even rusted and they can be sold to the informal sector or directly sold to steal manufactures. Estimated quantity of inert materials in the dumpsite is given in Table 2.26.
Table 2.26 Estimated quantity of inert materials in the dumpsite based on a fraction of different materials
Year
TPD Disposal (wb) Disposal (Db) Scrap metal 55
0.005
C&D
Glass Ceramic
0.063 0.046
0.022
1980
67
200,750.00
100,375.00
497
6,324
23
140
1990
82
244,713.13
122,356.56
606
7,709
28
170
2000
100
298,303.94
149,151.97
739
9,397
34
208
2010
121
363,630.84
181,815.42
901 11,455
41
253
2,743 34,886
126
771
Total l. Air emission control system
The quality of exhaust fumes is detected for dioxins in order to increase the secondary combustion temperature and also to increase the temperature at primary combustion, so as to reduce the dioxin concentration to the required standards. High temperature gasification is the proposed system, while maintaining high temperature at the secondary combustion with LFG. The advantage of the LFG is to ensure a stratified flame that can reduce the NOx levels, thus requiring less catalytic conversions. The amount of LFG at the secondary combustion can be varied to ensure high temperature at low NOx emissions. However, fuel NO formations are likely and selective catalytic reduction is a must. Instead of flue gas recirculation, which is another technique to reduce NOx formations, the presence of CO2 in LFG will prevent excessive prompt and thermal NO formations, since carbon monoxide radicals are formed which then combust once again in the stratified flame. For the removal of sulfur dioxide, flue gas desulfurization is done. The particulate is removed with electrostatic precipitators and semi-dry absorber with bag hose filters. The maximum expected emission levels which will be monitored continuously along with the flow rate are: NO, SO2, CO and Particulate Matter in 2.14 g/s, 0.66 g/s, 0.23 g/s and 0.166 g/s mass flow rates, respectively, at an average flue gas flow rate of 24000m3 /hr. m. Buffer zone
The boundaries have not been demarcated, since there are additional number of houses to be relocated and the reallocation of lands was done only recently between the two organizations; National Water Supply & Drainage Board and the Company. n. noise and vibration control strategies
i. noise/vibration generation points The details have yet to be received from the manufacturer. ii. control strategies. The details have yet to be received from the manufacturer.
o. infrastructure facilities required /provided
i. operating room (control panel etc.) There will be two operating rooms for power plant and landfill bioreactor. Main gate security room will have the Weighing bridge scale recording and monitoring of incoming vehicles and vehicle washing unit. Power plant will have a one centralized operating room with all the facilities for remote monitoring. The details of the control room have yet to be received from the manufacturer. ii. Vehicle cleaning and parking facilities There will be one vehicle washing plant with tyre wash bay and high pressure guns for body wash. Every waste transporting vehicle will be washed each time before leaving the site. Waste handling machines will be cleaned at the same facility every day. There will not be any parking facility for waste collection and transport vehicles, but waste handling machinery will have a parking shed facility of 110 m2 with maintenance facility. Main administrative complex will have the main vehicle parking facility of 120 m2 and Power plant area will also have a vehicle parking facility that can accommodate long vehicles. iii. Safety devices /fire protection facilities/lightening protection facilities The details have yet to be received from the manufacturer. iv. Construction of new roads and /or improvements of access roads (if any) A 6 m wide new access road will be constructed from the South Western side of the proposed site. See Figure 2.31 Project layout. v. Storage facilities, warehousing etc. Existing warehouses near to the temple at North Western side of the site will be rehabilitated and used as warehouses and storage in the initial phase. After constructing MRF facility, there will be separate storage facility. p. any other components (if any)
2.1.3. Project layout
Tomainroad G se cito io na sc y ste Lan dfx iltlra B re to rm (Peradeniya-Katugastota) LandfillBioreactor-2 a t0 dm um p (2 o nthscapasity) (24m onthscapasity) Existingbalancingtank
C onstructedW etland
Landfill B ioreactor-1 (18monthscapasity)
B ufferZone LeachateTreatm ent Bioreactor
B uffer zone Leachatetreatm enttanks Storag eFacility
Tom ainroad (Peradeniya-Katugastota)
A reafortheproposed inert landfill
Pow erPlant Tyrew ashpit &w eighbridge Serviceroads
A ccessroad
M aterial R ecovery Facility(M R F)
SecurityR oom
B ufferZone
R E V I I R I L E W A H A M
A dm inistrativeC om plex M achineryparking, repairandm aintenan ce
R oadtow aterIntake
Tem porarySiteO ffice &vehicleParkingArea
Figure 2.31 Project Layout
existing surface water bodies within the site should be provided of appropriate scale, order to get a clear picture of the project.
2.1.4 Implementation schedule
The implementation schedule is given in table 2.29 below. 2.1.5 Operational activities
i. Details of operation and maintenance activities, schedule of collection and disposal Operational plan
ii. Water requirements (sources and quantities) The water requirements in project operation are as following table 2.27. Table 2.27 Water requirements
Water Use
Drinking & Sanitary Water Vehicle Washing Plant Irrigation Power Plant
Amount 3 (m /day) 9.4
8 715 150
Source
National Water supply and Drainage Board Abundant Large Well at the Site Abundant Large Well at the Site Abundant Large Well at the Site
2.1.6 Relocation of settlers
No of families to be relocated Places to be relocated Permanent and temporary structures Facilities to be provided 2.1.7 Work force
i. Labour requirements (during construction and operation) The labour requirements in project constructional and operational phases are as following table 2.28 Table 2.28 Labour Requirement Type of labour required Constructional Supervisors 4 Skilled Labour 6 Labour 20 Total 30
Operational 3 6 12 21
Table 2.29 Implementation Schedule No
1 2 3 4 5 6 7 8 9
Activity
EIA approvals Leachate Treatment Construction of Administrative Complex Vehicle wash and other facilities Access Road to Dumpsite Relocation of First Two Houses Construction of MRF and Operation Dumpsite grading and leveling Removal of Small Dumpsite 9.1 Construction of Landfill Bioreactor 9.2 Stage I 10 Stage II 11 Installation of gas wells, pipes and turf 12 Flairing of Landfill Gas 13 Operation of Landfill Bioreactor 14 Relocation of rest of the settlers Fencing around the site 15 16 Power Plant 16.1 Finalysing Power Plant 16.2 Signing of Contract and 1st Payment 16.3 Training 16.4 Power Plant construction 16.5 Commissioning of power plant
M1 M 2
M3
M4
M5
Year 1 M6 M7
M8
Year 2 M 9 M 10 M 11 M 12 M 13 M 14 M 15
ii. Employment of local people during preconstruction, construction and operation Local people residing within the proposed site that are working in the dumpsite as scavengers will be given the priority when selecting the labour force. Two skilled labours trained at the University of Peradeniya will work as supervisors in landfill bioreactor and material recovery facility operation and construction. During the power plant construction there will be a specialized work force working with the recommendation of the power plant manufacturer. During its operation there will be a trained supervisor and skilled labours working under the management staff. iii. Availability of skilled labour There are few skilled labours locally available within the site for operation of excavator, bulldozer and tractors and for rough masonry work. iv. Occupational health and safety provided All the staff will be covered under a health and accidental insurance cover. Activated carbon masks, gloves, boots, head gears and overall will be provided and the project management will be strict on wearing safety gears at work. During rainy season rain coats will be provided for all of the worker. Every measure will be taken in MRF and Power Plant to protect the labour from accidents. Frequent monitoring and repairing of machinery will help in reducing labour injuries. First aid kits will be available in administrative complex, MRF and power plant. Sanitary facilities and disinfection allowances will be provided for the work force. v. Facilities required or provided Two workers rest facilities will be provided for women and men and each will have a separate changing room facility, sanitary facility, drinking water, first aid facility, and store facility for boots, gloves and other safety gears. A common and good quality restaurant facility will be provided for all. vi. Scavengers (permitted or not) if yes plan for incorporating them in to operations, age limits No scavenging activity will be allowed within the project premises. 2.1.8 Any offsite infrastructure facilities envisaged
2.2 Analyses of Alternatives
The following alternatives could be described 2.2.1 “no action’’ alternative The dumpsite cannot be used and it needs rehabilitation. The CEA has taken legal action against the KMC, thus no action alternative cannot be considered. 2.2.2 Alternative sites
At the beginning of developing the project, a site was selected in ……and there were protests against establishing any type of disposal facility, including waste to energy plant and the cost of transportation the wastes was a negative factor, thus compelled to withdraw the idea. The decision was made by the then Chairman CEA. The recent cite that was selected by the CEA was examined. The main reason for not considering the site is the reduction of Kandian cultural values, while creating undue pressures on the people living in the villages. 2.2.3 Alternative scales of the project
The project cannot be scaled down by not mining the dumpsite. However, the pollution will continue for a very long time to come. 2.2.4 Alternative designs, construction techniques, operation and maintenance procedures
The composting of MSW is an alternative, but the quality of the compost is questionable. Furthermore, low temperatures and high rainfall in Kandy is not conducive to composting. Nevertheless, it is an alternative technology in the Policy document of managing MSW. 2.2.5. Alternative ways of dealing with environmental impacts
CHAPTER 3 DESCRIPTION OF THE ENVIRONMENT
3.1 Physical Environment
Selected site is situated adjacent to the north western boundary of Kandy city and 3km away from the city of Kandy. Its location coordinates are 7° 18‟ to 45.89” N and 80° 37‟to 19.87” E which lies at an altitude of 461 m above mean sea level. The site is located in a valley surrounded by mountain ridges from all sides. Wattaramthanna range with a peak of 510m is located towards east in about 0.5 km distance to the site. Highly ecologically valuable two mountain ranges like Hantana and Udawattakelle are located towards the south east of the area making the situation more critical. To the south and south west of the site lies the Gannoruwa mountain range with a peak of 570m. Mahathanna Watta mountains with its highest peak of 725m are situated towards western side of the area at a distance of about 4km. Entire surrounding area is with hilly undulating terrain with vital eco systems, which makes it imperative that a proper attention is paid on the possible effects of emissions from the power plant. The location map of the surrounding area is given in Figure ….. The contour plan of the site is also given in Annexure 6.1 3.1.2 Geology and soil
3.1.2.1 General geology of the area 3.1.2.2. Soil type distribution a. Soil characteristics According to the FT-IR analysis it can be observed that the soils in the downstream of Gohagoda dump site shows kaolin type clay structure and clay is lack of organic matter. Analysis of soils contaminated by i. Total metal concentration
The sample locations were selected in order to determine the physical environmental characteristics of the study area such as: topography, surface water drainage pattern and quality, flow regimes and streams draining the area. For the purpose to ensure representative and same condition in all samples, soil samples were collected from auger at 0.5 m above to the bed rock and closer to the bed rock as shown in Figure 3.1.
Figure 3.1: Sample locations and depth of samples
The total quantity of metals extracted from 0.5 m above from the bed rock polluted soils were recorded as Zn>Cu>Pb> Cr > Ni >Cd concentrations and had a significant increasing pattern from the river towards the dumpsite direction (Figure 3.2). Accordingly, the highest total concentration of heavy metal recorded was Zn (318.45 mg/kg) and Cu, Pb, Cr, Ni and Cd; 124.1, 98.45, 69.85, 70.15 3.45 mg/kg respectively. A scattered metal behavior was recorded closer to bed rock as shown in Figure 3.3. According to observed data all binding sites in soil particles may have been occupied by metals in the upper layer. Thereafter can be facilitated to move towards down wards and the deeper soil layer may adsorb toxic metals. That may be the reason for the unique pattern observed at 0.5 m above layer from the bed rock.
Figure 3.2 Total metal concentrations of soil – 0.5m above from bed rock
Figure 3.3 Total metal concentrations of bottom layer ii. Exchangeable metal fraction
The heavy metals in the exchangeable fraction can be released rapidly to the environment. According to the exchangeable metal fraction results as shown in Figure 3.4, the predominant heavy metal recorded is Zn (59.4 mg/kg) and it may cause a threat to the surrounding environment since the concentrations are high. Further, Pb, Ni, Cu were recorded as 10.05, 7.35, 5.05 mg/kg respectively and Cr was not recorded as exchangeable although a significant amount was detected in total metal content. This may be a reason due to the representation of negatively charged complexes of soil in fewer amounts. Comparable less values for recorded cation exchange capacity (49.09 meq/100g) and specific surface area (9.25 m2 /g) determinations reveals enough evidences to confirm that the analyzed soil has low ability to absorb in to it‟s outer -sphere.
Figure 3.4 Exchangeable metal fraction of bottom layer
iii. Bioavailable fraction
The heavy metal elements can be transferred from abiotic (soil) to biotic environments and further facilitated to enter to the food chains by bioaccumulation. According to the results upper layer soil samples had high concentration of heavy metal such as Pb, Zn, Cu, Ni, Cd; 38.25, 10.45, 8.85, 3.60, 2.65 mg/kg, respectively (Figure 3.5). Low metal concentrations at the bottom layer was recorded as Zn, Pb, Cd; 4.55, 3.20, 1.65 mg/kg respectively and Cu, Ni and Cr were not in measurable amount as shown in Fig. 6. This result can be arisen due to many factors associated with soil; desorption and solubilization of mineral phases etc. Furthermore, these metal leaching patterns are similar to the total concentration variation at the bottom and upper layers soil sample leaching patterns.
Figure 3.5 Bioavailable metal fraction of soil – 0.5m above from bed rock
Figure 3.6 Bioavailable metal fraction of bottom layer
The presence of high concentration of heavy metal in soil is considerably high in Gohagoda open landfill area compared to the regulatory limits of other countries. High toxic metal concentrations in exchangeable and bioavailable fractions express the risk on local living being as well as the open water bodies such as rivers and groundwater sources. It is important to evaluate the potential risk to environment, and can be concluded that the soils play a major role as a natural attenuator for toxic metals however the release of these metals into the water bodies and plants especially after exceeding the capacity of binding may create problems in the future.
3.1.2.3. Height of ground water table 3.1.2.4. Ground stratification and permeability 3.1.2.4. Land use capabilities 3.2 Meteorology
The project area is located within the Wet zone mid country, which experiences a rainy, humid and mild climate. 3.2.1 Temperature
Long-term records of temperature are not available in the project area. However, it is anticipated that the temperature patterns occurring in the project area are comparable to the temperature variations occurring in the Gannoruwa area. For the period of 2001-2010, the mean annual temperature was 25.5oC with mean maximum and minimum temperatures of 29.9oC and 21.0oC, respectively. Table 3.1 presents the average monthly temperature in the Gannoruwa area during the period of 2001- 2010. The warmest months are April, May and March while the coldest months are December and January. Table 3.1: Average monthly temperature for years 2001-2010 Month
o
Temperature C
January
24.3
February
25.1
March
26.3
April
26.5
May
26.3
June
25.8
July
25.3
August
25.4
September
25.4
October
25.4
November
25.1
December
24.5
3.2.2 Wind patterns
No long-term records of wind patterns are available in the project area. However, it is anticipated that the wind patterns occurring in the project area are also similar to the wind patterns occurring in the Gannoruwa area. Table 3.2 presents the monthly maximum wind
speed experienced in the period of 2001 to 2010.The maximum wind speed was reported in February, 2002. Table 3.2: Monthly maximum wind speed of Gannoruwa from year 2001-2010
Note: *** Not observed
3.2.3 Relative humidity
Recent data pertaining to the relative humidity are not available in the project area. However, the project area experiences a humid climate and according to the data reported in the period of 2001-2010, the maximum daily pan evaporation was reported in February 2010 amounting to 10 mm, while minimum was 0.1mm in December, 2006. Tables 3.3 -3.5 show the average monthly evaporation and humidity data collected from the Gannoruwa area and it is anticipated that the data presented in Tables 3.3 -3.5 are also similar to the average monthly evaporation and humidity patterns occurring in the project area. The mean humidity throughout the year is around 70 % in evenings and 81 % in mornings and the average annual evaporation is about 1123 mm. Table 3.3: Average monthly pan evaporation in the Gannoruwa area for the period of 2001-2010 Month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Evaporation (mm)
107
124
124
90
96
90
81
90
91
76
67
88
Month January February March April May June July August September October November
Date 7-Jan-2002 23-Feb-2002 9-Mar-2002 5-Apr-2007 17-May-2002 23-Jun-2002 7-Jul-2001 2-Aug-2001 30-Sep-2001 6-Oct-2001 29-Nov-2007 -
Direction Morning E E E
Evening E E E
6.45 5.45 6.88
E NW ***
ESE *** ***
7.30 6.19 8.1 4.81 11.10
SW W W SW E
SW SSW SW S E
Wind (km/h) 11.19 14.66 9.42
speed
Table 3.4: Mean daily pan evaporation of Gannoruwa for the period of 2001-2010
Month
Mean Daily Evaporation (mm)
January
3.5
February
4.4
March
4.1
April
3.0
May
3.1
June
3.0
July
2.6
August
2.9
September
2.8
October
2.4
November
2.2
December
3.0
Table 3.5: Mean humidity for the period of 2001-2010 Month
Morning (%)
Evening (%)
January
80
65
February
77
56
March
79
60
April
84
73
May
80
73
June
81
74
July
83
75
August
81
72
September
79
72
October
82
76
November
84
77
December
82
72
3.2.4 Rainfall
Tables 3.6 shows the average monthly rainfall data reported at the Meteorological Department at Gannoruwa. According to that the average annual rainfall is 1973.9mm. Figure 3.6 illustrates the cumulative rainfall variation from 2001 to 2010.
Table 3.6: Mean Rainfall for the period of 2001-2010 Average monthly RF (mm)
Daily average RF (mm)
Jan
76.2
2.5
Feb
42.3
1.5
Mar
163.1
5.3
Apr
298.2
9.9
May
128.7
4.2
Jun
150.2
5.0
Jul
152.0
4.9
Aug
108.3
3.5
Sep
136.9
4.6
Oct
254.5
8.2
Nov
282.7
9.4
Dec
180.7
5.8
Month
2500 cum 2001 ) 2000
cum 2002
m m ( l l a 1500 f n i a r e v i t 1000 a l i m u C
cum 2003 cum 2004 cum 2005 cum 2006 cum 2007 cum 2008 cum 2009
500
cum 2010 0 0
1
2
3
4
5
6
7
Month
8
9
10
11
12
13
Figure 3.6: Cumulative rainfall variation during year 2001 to 2010 in Ganoruwa
3.3 Hydrology 3.3.1. Surface water drainage pattern
The study area have three small watersheds as shown in Figure .. The dumpsite is located in the largest one, having an area of 184,765 m2 of which approximate 40% of the land is used for the dump. The hydrological characteristics are very much influenced by the dump. Unlike any other watershed, the wastes have greatly influenced the water absorption capacity, permeating rate and therefore the release is partially governed by the soil permeability. Although, the stream of the sub-watershed was a dry one during non rainy seasons, now has considerable base flow, nearly 1 m3 /h. The measurements were made with V-Notch weirs that were installed to obtain the flow rates from the three subcatchments. Also the three flows that joined the main stream were measured. Unfortunately, all of them got washed away with the storm that occurred. However, the random measurements of flow during the storms and accurate base flow readings, permitted to develop a simple model. It is based on the concept of releasing subsurface flows that eventually discharge as base flow, since shallow confining layers exists in the location where the waste is dumped. 3.3.2 Flow regime of the streams draining the area
The rainfall data, ET and the observations permitted to develop a hydrograph based on this model considering the water balance of the dump for the sub-watershed. The equilibrium water balance model is based on methods proposed by Budyko (1958) and Fu (1981) and further developed by Milly (1994) and Zhang et al., (2001, 2004). In determining the water balance the index of dryness defined as the ratio of potential evapo-transpiration to precipitation was found to be a dominant factor (Zhang et al., xx) It would be apt to include another term “baseflow” to the dryness index and thus, term as “storage deletion”, SD index. Therefore, the absorption capacity will depend on the maximum SD value for the duration considered. ET B f RF
SD
Higher the SD value, runoff will be lower. Also there are number of equations developed to determine accurately the baseflow. The baseflow component of streams represents the withdrawal of groundwater from storage. As the stream drains water from the groundwater reservoir, the water table falls, and the baseflow to the stream decreases. Baseflow recession can be expressed by the following equation: Qb
kt
Qoe
Where Q is the discharge at some time after the initiation of recession, Q o is the discharge at the start of the recession, t is the time since the recession began, and k is a constant for the basin. A plot of lnQ versus t therefore gives the value of k from the slope of the line. In
this watershed the minimum flow measured were very constant, indicating that there is large reservoir within the watershed. The above equation can also be written as; Qb
t
QoK
. Where, t can be either +ve or negative – ve, depending on the recession limb, turning point or rising within the period of recession as illustrated in Figure 3.7.
30 y 25 a d / m20 m n 15 i Q 10 w o l F 5
Total flow
Recession Threshold Baseflow
0 5
7
9
11
Time in days
13 15 Turning point
Figure 3.7: Illustration of baseflow variations with time for calculating recession flow
The storage of water within the watershed can be written for a rainfall event as; S RF RO Q d b
Where, ∆S = change in storage capacity in mm for a unit area. It could either be above or below the maximum storage Sm for a unit area and over a period of time, it will approach; Sm = ∑Qb+ ∑ET , RF = Rainfall in mm, ROd = Direct runoff of a storm in mm defined as (1-SD) Qb = Measured base flow for a unit area of the dump in mm ET = Pan evaporation in mm ET , ∆S f < ∆S i, since i = initial and f = final The condition where ∆S f = ∆S i -Qb – Q = Qb+ ROd + ∆S , for the condition, when change in storage capacity ∆S is above the maximum storage Sm and when ∆S is below S m; Q = Q b+ ROd and in the absence of rainfall, Q = Qb
The Figure 3.8 was developed from the following data; Qb = 0.000274 m3/s Ad = 30,500 m2, the area of sub-watershed of the dump
Qbu
Qb Ad
, mm/s
= Qb per unit area RF = in mm/hr measured over a period of one month and converted to mm/day ROd = 0.2 of RF , since SD =0.8 for the dry period examined for each storm event on the
same day. The maximum period of direct runoff is one day, therefore in the recession curve, K value can be obtained, assuming that Qb is 0.1 at the minimum turning point and the Qo is maximum flow of total RF of one day, then K =0.1, since t=1 from turning point. It can be considered as lag flow. When there are several rainfall incidences, the computation should be the same.
700 600
y a d / 500 m m400 e g a h 300 c s i d 200 Q
Rainfall Discharge
100 0 1 3
5 7
9 11 13 15 17 19 21 23 25 27 29 31
Time in days
Figure 3.8: Generated discharges Q in mm/day for a unit area from the prediction model vs time for the highest rainfall and highest rainfall intensity recorded at the Gohagoda Dumpsite
The Figure 3.8 shows the generated discharges for the period 1st to 31st December 2010. In applying the same model on the entire watershed, it indicates the difference of resistance to flow. The base flow rates were governed by the groundwater permeability, see Table 3.7. As expected, the lowest permeability was for the dump, next lowest the entire watershed and highest the area without the dump. The comparative cumulative discharges illustrated in Figure 3.9 manifest these differences. Table 3.7: The relationship of baseflow from groundwater and permeability of watershed Extent m2
Base flow Mm/m2 /month
Base flow m3 /month
Gross Permeability cm/s
30,500
24.06
734
8.98E-07
Sub-watershed without dump
144,500
52.61
7,602
1.96E-06
Total watershed
175,000
47.63
8,335
1.78E-06
Category Sub-watershed Dump
The average flow can be considered as the baseflow from the dump. It can account for approximately 9,000 m3 and the remaining 21,000 m3 for the year is washed out for every rainfall event. The retention time is very low and the pollution loads are considerable. It is important to continue this study so that management should be automated to cope with the large variations of day and night discharges as shown in Figure 3.10 In comparison, the sub-watershed without the dump manifests an interesting pattern showing the influence of ET on reduction of and the dew contribution in the night as illustrated in Figure 3.11 These influences perhaps are more pronounced in a river basin. It is a good example of dew contribution as precipitation. Total WS
Dumpsite WS
WS without Dump
350,000 3 300,000 m n 250,000 i Q200,000 e v i t 150,000 a l u 100,000 m u C 50,000
0 0
5
10
15
20
25
30
35
Time in days
Figure 3.9: A comparison of the cumulative discharges of the entire watershed (WS) and sub-watershed without dump and the dumpsite
0.70 0.60 0.50 s 0.40 / l Q
0.30 0.20 0.10 0.00 12:00 AM
12:00 PM
12:00 AM
12:00 PM
12:00 AM
Figure 3.10: Stream flow (baseflow) measurements in the dry season of the d umpsite
4.00 3.50 3.00 2.50
s / l 2.00 Q
1.50 1.00 0.50 0.00 12:00 AM
12:00 PM
12:00 AM
12:00 PM
12:00 AM
Figure 3.11: Stream flow (baseflow) measurements in the dry season of the subwatershed excluding dumpsite
3.3.3 Occurrence of floods
Ten year flood flow data of the Mahaweli River was analyzed according to the flood hazard analysis (statistical methods). The study took into account nature of the flood hydrograph, peak flow vs. shape/volume. The probability analysis required data selection and processing. The log values of the flows were obtained and then ranked them from low to highest. The selection was made according to number of occurrences, such that the Figure 3.12 can give the relationship between the maximum discharges for difference recurrence intervals. Although, 10 year flood flow data was used, it is very much applicable since the Kotmale Dam reduces risk of flooding. The maximum rise in the water level will inundate the paddy fields of the low lying lands of the main watershed.
y = 64.701x + 125.44 s /
3
R2 = 0.9606
900
m E800 G R700 A H600 C S I 500 D . 400 X A300 M L 200 A U100 N N 0 A
0.00
2.00
4.00
6.00
8.00
10.00
12.00
REOCCURANCE INTERVAL Years
Figure 3.12: Annual maximum discharges and its recurrence intervals based on records of ten years
3.3.4 Surface water quality
The sampling points were located and positioned in order to represent the entire area of Gohagoda dumpsite. S1 was on the main dumpsite and S2, S3, S4, S5, S6 were around the boundaries of main dumping area. D1 and D2 were taken from old dump and new burned dump area respectively. Then C1 was located on main canal which drain directly to the Mahaweli river, while R2 was located on discharge point to the river. And R1, R3 were located on upstream and down steam of the river respectively. The locations of the sampling points are shown in the Plate 3.1.
Plate 3.11: Locations of sampling points
The collected samples were analyzed for the parameters of pH, electrical conductivity (EC), Salinity, total dissolved solid (TDS), total solid (TS), volatile solid (VS), total suspended solid (TSS), volatile suspended solid (VSS), biochemical oxygen demand (BOD), Nitrate, Phosphate, using standard methods. In summarizing the study done by Widanagamege, 2010 the EC measurements were within the range of 1.12 to 9.32 mS and it is typical of a MSW dumpsite (Pathirana, 2006). The salinity levels were very low in upstream samples of river at the beginning and then increased significantly. All other samples showed higher variations of salinity values within the range of 0-0.8%. The contribution of salinity to the river can be clearly seen in Annexure 2. . In evaluating the data, influencing the river flow, the pH had decreased, although upstream and incoming effluent pH levels were higher. TDS were within 5006000 mg/l range. In general, TS fluctuations were high since decomposition and burning create high content of TS and VS. Very low values of TS and VS were recorded in the stream flow. There were low nitrate nitrogen and after a dry spell, the nitrate nitrogen values in the river were higher than downstream and at the discharge point, but the process reversed after sometime. The phosphate levels varied considerably. The quality and quantity generated from dumpsite was strongly influenced by the hydrological conditions. In an earlier study, the BOD value reported was 7500 mg/l (Manikpura et al., 2008). In this study the BOD and COD values puddles on top of the dumpsite were 4800 and 32000, respectively. Sometimes due to toxicity and other complications a lower BOD values are recorded. The results of upstream (R1) in comparison to downstream after river water mixing with (R2) clearly show the level of pollution. The total loads could be considerable considering the washouts from the top of the dumpsite, let alone the baseflow. Additional burden is the effluent discharges from the piggery as shown in S6 values. The pollution level of river
increases with the additions from Gohagoda stream flow. The quality parameters of discharge flow were very much higher than standard values. 3.3.5 Groundwater levels
Figure 3.13: Bore hole locations
Table 3.8: Borehole details
Bore hole No
Total Depth (m)
Permeability (m3 /s) -10 X 10
Remarks
P1
0.46
gray soil, could not observe
P2
0.54
0.182
P3
0.41
7.350
P4
1.03
0.186
First 35 cm depth was a soil layer, thereafter decomposed waste layer could be observed
P5
0.73
2.820
First 30 cm depth was a soil layer, thereafter decomposed waste layer and flowing on the surface could be observed
P6
0.64
1.410
First 45 cm depth was a soil layer, thereafter decomposed waste layer and flowing on the surface could be observed
P7
0.48
Could not dig further due to aggregates and beneath, could not observed
P8
0.61
no / quarry dust in the bottom layer
P9
0.54
8.030
Could not observe a soil cover
P10
0.76
62.500
Could not observe a soil cover
P11
0.58
Could not dig further due to waste material, stagnating on the surface was observed and there was not underneath
P12
0.28
Could not dig further due to … stagnating on the surface was observed and there was not underneath
P13
0.52
Could not dig further due to gravel waste material, stagnating on the surface was observed and there was not underneath
P14
0.63
Could not dig further due to gravel, stagnating on the surface was observed and there was not underneath
P15
0.82
4.630
First 20 cm depth was a soil layer, and flowing on the surface could be observed, underneath there was
P16
0.47
7.540
First 30 cm depth was a soil layer, thereafter decomposed waste layer
P17
0.82
P18
0.33
2.800
First 30 cm depth was a soil layer, thereafter decomposed waste layer
P19
0.48
1.090
First 35 cm depth was a soil layer, thereafter decomposed waste layer
P20
1
It was only a soil layer, could not observe
P21
0.86
could not observe waste layer or , wastewater from a nearby piggery was flowing on the surface
First 30 cm depth was a soil layer, thereafter decomposed waste layer could be observed First 30 cm depth was a soil layer, thereafter decomposed waste layer could be observed
There was not measurable quantity of
Ground water quality Surface water uses including water intake points Ground water uses
3.4 Land use
The existing land use pattern within 500m radius of the project site is given in Table 3.9.
Table 3.9 :Land use pattern within 500 m radius of the project site 2
Description
Area (m )
Percentage
Waste dump
51,735
6.59
Abundant paddy fields
19,400
2.47
Cultivated paddy fields
57,165
7.28
9,518
1.21
Mahaweli river
88,122
11.22
Roads
27,645
3.51
Home gardens
531,813
67.71
Total
785,398
100
Commercial
3.5 Air quality
Inventory of existing emission sources and ambient air quality measurements
3.6 Noise
Inventory of existing noise sources and ambient noise levels
3.7 Ecological Resources
The site is located in Wet zone mid country within WM3b agro climate zone (Harispattuwa DSD) where mean annual rainfall exceed 2500mm. WM3b climate zone is characterized by presence of well developed Kandyan home gardens (Punyawardena, 2008). Geomorphologically, the site is part of rolling and hilly landscape of the area. According to local informants, the site was part of Gohagoda village system with luxuriant home gardens until some 30 years back. Mahaweli River makes the eastern boundary of the land while north and south are bounded by marsh lands which were formerly tracts of paddy lands. The dumping site is an elevated (10m-15m) land area bounded by marshes and Mahaweli River in three sides. Except for the centrally located dumping site, the rest of the project area has good vegetation cover representing various habitats types that have evolved due to long term human habitation and disturbances. Weedy plants and agricultural crop plants characteristic of Kandyan home gardens are the leading floristic elements in the area. 3.7.1 Vegetation types identified
Several vegetation types (9) were identified in the project area and their characteristics are as follows. 3.7.1.1 Grasslands - away from dumpsite
They occur on peripheral lands of the dumping site where tree cover has destroyed due to various human activities such as grass cutting, grazing by cattle, fire, removal of timber, firewood gathering etc. Grasslands have a simple vegetation structure; just the closely grown grassy cover up to 2m in height. Occasionally, isolated and scattered trees (up to 20m) and shrub (up to 3m) species can be seen. 3.7.1.2 Home gardens – existing
Home gardens are the vegetation found immediately around homesteads which are results of long term human manipulations. Occurrence of tree dominated multipurpose vegetation community arranged similar to a natural forest is one of the main characteristic features of these home gardens. Best developed multi-storey home gardens can be located in the eastern part of the site close to Mahaweli River. However, the appearance varies in relation to the individual farmer practice. Generally, there are several plant layers; canopy 20m, sub canopy 10m and shrub/herb layer 2m could be recognized. Continuous canopy allow very little light to reach the ground. Often the structure is fast changing in time and space due to weeding, pruning, fencing, digging etc. More exotic and agricultural crop species are found in this habitat. Also, home garden is an important faunal habitat providing animals with feeding and nesting sites. It provides people with fruits, nuts, yams, flowers, vegetables, medicines, firewood, timber etc. throughout the year.
3.7.1.3 Home gardens - abandoned
Abandoned home gardens also have a fairly similar structure as in managed home gardens. However, plants of the lower layers i.e. herbs and shrubs, are mostly weedy species growing abundantly with no management. 3.7.1.4 Marshland - abandoned paddy land
Marshlands have resulted from long term abandonment of terraced paddy lands in low laying areas of the site. Aquatic or semi-aquatic shrubs and herbs are abundant in this habitat. Ludwigia shrubs growing up to 2m are the dominant plant in many sites. Generally, the site is characterized by excessive growth of aquatic weeds. 3.7.1.5. Riverine forests
The riverine forest is found along the banks of Mahaweli river streams. The distribution of this vegetation type is as narrow as 10m. Vegetation height is about 15m-20m with a partly closed canopy belt of forests. Sub-canopy (10m) and shrubs/herbs (1m-2m) layers can also be distinguished. Bamboo is a dominant component in this habitat. Natural rivrine species such as Kumbuk and Mee are lacking in this strip of vegetation due to long term disturbance. Riverine forests form the inter phase between stream and other terrestrial habitats. It is the frontline defense against stream bank erosion due to water currents. Thick root system of trees and shrubs acts as a protective cushion covering the banks. Well developed riverine forests provide convenient resting sites for birds, bats, reptiles, amphibians etc. 3.7.1.6 Shrublands - Short
Scrublands - short are characterized by one stratum of shrubs (up to 2 m) with many grass species grown as a thicket. Grazing by cattle, site disturbance and removal of tree vegetation has lead to the formation of such shrublands. Most shrublands are distributed around the dump site. They occur as a patch work over the landscape. Vulnerability to fire is more or less similar to grasslands. Shrublands are good resting places of insects and some other small mammals. 3.7.1.7 Shrublands – Tall
The tall version of shrubland has shrubs growing up to above 2m and below 5m and has a very simple structure; two strata could be recognized. Shrubs, mainly Thelendaru (Ricinus communis) are scattered over the expanse of grasslands. They do not form a continuous canopy. An important feature of these shrublands is that they are well adapted to disturbed and unfavorable site conditions including garbage accumulation. The tall shrubs are an advanced growth stage of short shrubland in absence of grazing pressure and other mechanical disturbances.
3.7.1.8 Woodlands
Woodlands also have a similar structure as abandoned home gardens, but the flora (trees, shrubs and herbs) are the result of growing plants with total absence of human care. They are found especially on embankments near marshlands or the former terraced paddy lands.
3.7.1.9 Dumping site flora
Surviving flora of the sites with newly accumulated solid and liquid waste was considered as dumping site flora. The important visible feature of the flora is that most of the trees, which occupied former orchards/home gardens, are at varying stages of dying or showing unhealthiness due to impact of garbage accumulation at the ground. However, shrubs and herbs which are invading the garbage heap are well adapted weedy species for such harsh conditions. 3.7.2. Flora
A total of 165 species belonging to 47 families were recorded from the site and among them 15 species are noted invasive species (see Annexure …). No endemic or threatened plant species were encountered. 3.7.3 Abundance of plant species
The leading plant species reference life form and vegetation type are summarized in Table 1. Different vegetation types were dominated by different plant species as given in Annexure 2. 3.7.4 Fauna in the project area Faunal richness is the project site is extremely poor (Table 3.11). This area is experiencing regular disturbance, such as garbage trucks that bring waste materials to the site and, caterpillars piling- up and compacting garbage for a long period of time. Even in the marshland bordering the garbage dumping site is very poor in its faunal composition. from the dump drain into this marshland (formerly a paddy field) may be toxic to many ground living. Total list of fauna encountered during sampling is given in Annexure .. Table 3.10: Major plant species in different habitats Habitat code
1 2 2 2
vegetation type
Grasslands - away from dump site Homegardens abandoned Homegardens abandoned Homegardens abandoned
Life Form
Plant Species
Abundance
Local name
Herb
Panicum maximum
Tree
Castilla elastica
Panama rubber
81.82
Shrub
Neolitsea cassia
Kududawula
520.00
Herb
Rivina humilis
Divibiju
17.56
27.78
Avg.Cover per unit area Density per Ha Density per Ha Avg.Cover per unit area
3 3 3 4
4
Homegardens existing Homegardens existing Homegardens existing Marshland abandoned paddy land Marshland abandoned paddy land
Gliricidia sepium
Wetahira
300.00
Shrub
Gliricidia sepium
Wetahira
986.67
Herb
Setaria barbata
23.89
Shrub
Ludwigia octovalis
3,714.29
Density per Ha
Herb
Panicum maximum
23.24
Avg.Cover per unit area
5
Riverine forests
Tree
Bambusa vulgaris
5
Riverine forests
Shrub
Tithonia diversifolia
5
Riverine forests
Herb
Panicum maximum
6
Shrublands Short
Herb
Panicum maximum
7
Shrublands – Tall
Shrub
Lantana camara
Hinguru
7
Shrublands – Tall
Herb
Acalypha indica
kuppameniya
8
Woodlands
Tree
8
Woodlands
8
Woodlands
9 9 9
Dumping flora Dumping flora Dumping flora
–
site site
Kahauna
Panama rubber Panama rubber
Castilla elastica Castilla Shrub elastica
site
Density per Ha Density per Ha Avg.Cover per unit area
Tree
Herb
Panicum maximum
Tree
Cocos nucifera
Pol
Shrub
Ricinus communis
Edaru
Herb
Panicum repens
Etora
Density per Ha Density per 2,400.00 Ha Avg.Cover 100.00 per unit area Avg.Cover 80.00 per unit area Density per 1,040.00 Ha Avg.Cover 70.00 per unit area Density per 266.67 Ha Density per 400.00 Ha Avg.Cover 47.86 per unit area Density per 80.00 Ha Density per 1,300.00 Ha Avg.Cover 32.50 per unit area 1,600.00
Table 3.11: Summary of the fauna recorded from the project area Faunal Group
Total recorded
No. in Home Gardens
No. in the Dumping Site
Number in the Marshland
No. of Endemics
Butterflies
25
25
01
04
00
Amphibians
03
03
00
00
01
Reptiles
05
04
00
01
01
Birds
39
33
04
07
03
Mammals
09
05
03
01
00
3.3 Socio-economic Environment
Location of centers of population and settlements population characteristics Existing infrastructure facilities Housing and sanitation Principal economic activities Religious and cultural centers
CHAPTER 4 ASSESSMENT OF ANTICIPATED ENVIRONMENTAL IMPACTS Evaluation Criteria of Impacts The Leopold Matrix will be prepared after a brainstorming session. 4.1 Constructional Impacts
The following constructional impacts are identified. a. In the dry period, considerable dust loads are expected during construction. The fine clay soil in the site makes it difficult for workers and surrounding habitats. The site becomes very muddy during heavy rains and the dumpsite is not accessible. b. The present air pollution is the worse condition, since decomposing wastes are exposed and the particulate and odor nuisance is considerable. The impact will be less when controlled mining is undertaken. Nevertheless, it is a concerning problem that needs scientific and technological solutions that are acceptable. It is important to completely remove the dumpsite, but in the process of achieving this goal, water pollution will create adverse conditions. c. There will be considerable amount of heavy machinery and trucks that will ply through the site and the exit roads. The noise pollution will be considerable.
4.2 Operational impacts 4.2.1 Air 4.2.1.1 Types of emissions
At the beginning LFG is emitted to the atmosphere. The measured CH 4 emissions amounts to 288 g/m2 /day and once it is rehabilitated and torched, flue gases will consists of CO2, H2O, SOx, NOx and PM. However the concentrations will be very low. Table 4.1 gives approximate concentrations. The power plant will emit NO, SO2, CO and Particulate Matter in 2.14 g/s, 0.66 g/s, 0.23 g/s and 0.166 g/s, respectively. Table 4.1: Landfill gas composition Description
Value
Total Combustible Gases
60 - 65
%
Methane
55 - 62
%
4-7
ppm
1.2 -1.5
ppm
Total VOC Benzene
Units
Table 4.2 shows the emission levels specified by the supplier.
Table 4.2: Stack emission levels from the proposed power plant Parameter
Flue gas emission
Unit
m3
Value
/h
6000
NO
g/s
2.14
SO2
g/s
0.66
CO
g/s
0.23
Particulate Matter
g/s
0.166
4.2.1.3 Anticipated rate of discharge
The methane emissions based on point source measures with flux chambers of surface emissions may not be accurate, because uncontrolled LFG emissions occur on sporadic manner when gas pressure builds up and release within a short time (Ref Sardinia/Dileepe). The LFG emissions from the dumpsite are estimated at 4090 kg/day and it may approach extraction values of the LBR. Therefore, 6822 kg/day is a realistic value. The extractions will reduce methane losses at low pressures maintained in the dumpsite. It will replace 24000m3 /hr of flue gases from the thermal power plant. a. Impacts of emission on ambient air quality There are number of impacts on ambient air quality from the dumpsite with or without operating it. The methane emissions and other odorous landfill gases are the major concerns, since there will be an escape of LFGs from the capping and embankments. Not all of the gasses can be captured for providing gas for the WTE power plant. Although, the effect of LFGs will be reduced, they will be replaced with flue gas emissions from the power plant. b. Impact of odour due to processing of waste and excavation of existing waste In all of the activities, odour emissions are expected. It is a drawback and a concerning issue. The excavation of old wastes is a technological challenge and a necessity, since the ambient air quality will be affected even after closure of dumpsite. The developed filtration system is the solution to reduce odour nuisance. 4.2.2 Wastewater and other liquid effluent 4.2.2.1 Quality and quantity of effluent to be discharged to the environment
It is expected that the estimated and monitored quantity of that will be treated in an anaerobic reactor, ASP and finally in a Constructed Wetland will meet the required water quality standards of the CEA. The quantity as given earlier is 30,000 m3 /day. 4.2.2.2 Impacts of effluent disposal on ambient water quality of Mahaweli River
The impact will depend on the effectiveness of LTB and the amount of chemicals applied to precipitate the organic and inorganic components in the ASP and the final heavy metal uptake in the Constructed Wetland. a. Cooling water discharge There will be utmost efforts made to have closed loop systems. However, if the need arise in the final selection of machinery the discharge water will have a maximum of 60oC at a flow rate of 120m3 /day. If the hot water is discharged directly to the River it will cause adverse effects and avoidance is recommended.
b. Surface run offs The surface drains as shown in Figure 3.8 will be separated from the flows. Unfortunately there could be contamination from the polluted soil as given in Chapter 3. The accumulated heavy metals will be washed out. 4.2.3 Solid and hazardous waste 4.2.3.1. Accumulation of residue waste and possible impact
Almost all of the residue wastes will be sorted during the mining operation. Any of the materials that cannot be recycled or converted to RDF will pose environmental and management issues in the relocated final disposal. 4.2.3.2. Impacts due to disposal of sewage and sludge waste
The gully sucker wastes can be discharged into the ASP, but it may overload and there will be additional sludge to be disposed in a secure landfill. The odour emissions as well as difficulties in handling such wastes are the major impacts. However, mixing certain quantity of sewage with the will improve the ASP performance as reported by Thilakerathne, 2010. 4.2.3.3. Accumulation of hazardous waste and possible impacts
The most hazardous wastes found in the dumpsite are e-wastes and sharps. Approximately, 300g of e-wastes per tonne of wastes was found in the old dumpsites. They were more of electrical appliances, but now electronic wastes dominate. The latest finding is 2800g per tonne of wastes. Although, mathematically inaccurate, it is possible then to fit an exponential function to determine the intermediate values, such that a plot of e-wastes vs time can be plotted as shown in Figure 4.3. The total wastes disposed overtime can be multiplied by the predicted amounts to deduce the total e-wastes as given in Table 4.4. It should be noted that most of those wastes have hard plastics, including PVC. The sludge too is hazardous and needs safe disposal.
Table 4.4: Estimated quantity of e-wastes in the dumpsite Year
Disposed Tonnes
E-wastes g/tonne
Tonnes
1980
200,750
317
64
1990
244,713
656
160
2000
298,304
1355
404
2010
363,631
2800
1018
Total 1,107,398
1647 y = 1E-60e0.0726x
3000
R2 = 1
2500
s e n n 2000 o t / g s 1500 e t s a 1000 w E
500 0 1975
1980
1985
1990
1995
2000
2005
2010
2015
Year
Figure 4.3: Hypothetical increases in e-wastes with time
4.2.4 Noise and vibration
Sources of noise and vibration (including machinery, heavy vehicle movemets etc.) Predicted noise levels and impacts Manufacture‟s specifications are not given and expert findings are yet to be reported.
4.2.5 Ecological resources
Since the site is botanically inferior in respect to the occurrence of endemic and threatened plants, no on-site impacts on flora is expected due to project activities. Not a single species of endemic or threatened plants have survived in this garbage dump and associated human modified habitats due to unfavourable ecological conditions. In contrary, a large number of invasive plants species (15 species – see Appendix II) have found competitive advantage and established successfully. The occurrence of 15 invasive species in this single site is a matter of concern. In future, the site has to be managed in a way that it
provides no or minimum opportunities for the breeding and spread of invasive plants for surrounding areas. In fact, the draining of the land is towards the Mahaweli, therefore, there are good possibilities of spreading invasive plants to other areas using the river as the agent of dispersal.
4.2.6 Traffic impacts
In order to investigate the possible impact on traffic due to garbage trucks as a result of this project, few surveys were carried out. The main attention was paid to the Katugastota town. To facilitate the study a traffic count was administered targeting traffic flowing in main roads in Katugastota town including turning movement information for a period of 12 hours. Level Of Service (LOS) on roads at present and for 15 years was calculated based on a traffic growth of 4% per annum. In any of the calculations, there was no any significant effect indicated for the LOS due to garbage collectors passing through Katugastota town. A detailed analysis will follow with the next report
4.2.7 Human, economic and socio-economic impacts
Number of families to be affected and to be relocated Impacts on existing economic activities and income sources Changes in land use and land use pattern Impacts on access roads and transportation Impacts on historical sites/religious places Positive /negative impacts on health Positive / negative impacts on tourism Employment opportunities provided 4.2.8 Impacts on visual environment
Positive and or negative impacts There will certainly be a positive visual impact because the dumpsite is being rehabilitated and the shanty dwellings removed and relocated. However, there will be negative impacts when mining the dumpsite and LBRs.
CHAPTER 5 PROPOSED MITIGATORY MEASURES
5.1 Mitigation Measures During Construction
Dust and waste materials cause considerable problems during constructions and it is preferred then to undertake relocation of housing activities and be completed before the construction commences, particularly of the power plant. Although the houses on the …..will be set back, they will be affected when the first landfill bioreactor is constructed. Therefore, a barrier fence should be constructed between the housing and the proposed LBR. Landfill or dumpsite mining is a new concept to attain complete rehabilitation of existing dumpsites or sustainable landfills. In this instance, the dumpsite is mined under controlled conditions with shelter and gas purification system to mitigate pollution loads that will continue to pollute for a long time. Eventually, the dumpsite will be converted to a sustainable landfill. The duration of potential LFG extractions will depend on the feasibility of management without an income from the dumpsite. Therefore, the mining of the dumpsite becomes both environmentally and economically beneficial, let alone a progress in social development. In the case of LFR, it will have a complete solution, since aeration can be done with the pipes, whereas, effective aeration in dumpsites are questionable and yet to be perfected, refer to section below. It is recommended to confine all activities between 5 am and 8 pm. However, in ideal working conditions, which are becoming rear, in consultation with the immediate neighboring households, night work can be applied for approval from the Grama Niladari and Environmental Police. Most of the neighboring communities will agree to allow constructions, since they are also stakeholders of the project, particularly so when they are employed in the project. It is expected to employ over hundred workers during the construction. 5.2. Reductions in Operational Impacts
The methane gas and particulate emissions from the dumpsite will be replaced with polluting flue gases and escape of LFG. However, good practices of maintaining low pressure at the headers of the gas extraction wells, depending on the radius of influence, can reduce escape of LFG. The replacement of landfill gas with flue gases as a polluting agent from thermal power plants can be overcome with advanced flue gas control technologies that will be incorporated in proposed power plant. The level of pollution is less in this well equipped filtration system of NOx, SOx and PM control. In fact the concept developed by the University of Peradeniya to incorporate the dual fuel system will reduce both atmospheric pollution and filtration requirement. The replaced filters and hazardous materials will be disposed in a secure landfill or used for road constructions (ref…..).
There will be a positive impact on the ambient air, when the landfill bioreactors and thermal plant will function. The reductions in methane emissions as well as reduced compounds from the dumpsite will drastically improve the air quality. Therefore, the ambient air quality will improve with the rehabilitation works, but the thermal power plant will add pollution loads, but it will be dispersed to meet the required ambient air quality standards. 5.2.1 Atmospheric Pollution 5.2.1.1 Air pollution control and dispersion modeling
As a primary step of mitigating the environmental damage from emissions, due attention was paid to the selection of a power plant with proper air pollution controlling units. Table 4.2 in Chapter 4 shows the emission levels specified by the supplier. A thorough air pollution dispersion modeling was carried out in two steps to establish a suitable stack height for the power plant that would prevent ambient concentrations of pollutants exceeding the allowable limits. In the first step of modeling, the worst case scenario was established as follows 1. Even though only a 2.5 MW power plant would be established initially, the modeling was done for a power plant of 10 MW taking future expansions into account. 2. Initial Gaussian dispersion modeling was carried out using a spread sheet calculation procedure to establish the 24 hour maximum concentrations for the worst case stability, taking ground reflection into account. This method permitted the use of local metrological and topological data easily to investigate their effect on the ground level concentrations. Further, it was assumed that the wind direction would persist throughout the day towards the point which was under consideration for modeling, even though this would never happen in practice. The stack height required to reduce the ground level concentrations to permissible levels were established using this initial round of calculations. Initial calculations indicated that a stack height of 150 m is needed to ensure that the ambient levels would not exceed the permissible concentration levels of individual pollutants. A sample graph obtained through the calculations is shown in Figure 5.1 where the calculated maximum NO2 concentrations are shown. The highest concentration predicted was of 96.5 g/m3. Maximum permissible concentration levels and calculated maximum concentration levels are shown in Table 5.1 Table 5.1: Permissible concentration levels and maximum concentrations predicted
Pollutant Carbon Monoxide
Permissible Level Maximum Concentration (g/m3) 58,000
predicted (g/m3) 10.5
Particulate Matter
50
7.5
Nitrogen Dioxide
100
96.5
Sulphur Dioxide
80
29.7
Figure 5.1: Calculated maximum 24 h NO 2 concentration profile
3. A thorough modeling was then carried out using the dispersion modeling software Industrial Source Complex (ISC 3). Source strength, stack height, Meteorological data from Hanthana and Gannoruwa weather stations, and local topological data were the input for the model. Worst case stability parameters were again selected to simulate the maximum possible concentration levels. Figure 5.2 shows a section of a sample graph obtained from the ISC 3 model where NO concentrations are depicted. The maximum concentration levels predicted through this model were much lower than the values given in Table 5.1.
3
Figure 5.2: Concentration profile of NO 2 (g/m ) obtained from ISC 3
Similarly concentration profiles of SO2, CO, particulates matter were developed at a stack height of 150 m and found that the resulting ambient concentration levels would be lower than the permissible levels. Consequently, following steps are proposed to mitigate the environmental impacts from the air pollutant emissions 1. Initial verification of supplier specifications and regular maintenance of pollution control units to ensure emission levels remains close to specified values. 2. Dispersion of pollutants through a properly designed stack. The height of the stack should be more than 150 m and should have an internal exit diameter of less than 0.4 m to prevent the downwash of pollutants at high wind speeds. Provision must be made available to increase the height of the stack further, if monitoring results indicate the violation of regulatory requirements.
5.2.2 Aeration and management in dumpsite
A careful study of the mining procedure is required at every stage of mining it. It is important to isolate cells for mining, primarily for aerating, thus adequate surface drains are required. It is proposed to use the vertical wells installed for gas extractions to aerate the defined isolated cells, which can be termed in the phase of operation as “Aerating Cell” (AC) and “Mining Cell” (MC). The drained water should not be connected to surface drains. They should be at all times connected to the drain pipes or pumped to the nearest pipe network or better still in some points in the dumpsite to pump the directly to the treatment plant.
The shelter that has been suggested will reduce both impacts; odour nuisance and . The shelter will prevent moisture entering the isolated AC and working conditions will become ideal for mining. It may necessitate the use of polyethylene sheets to direct the odour gasses for treatment in the proposed wet and dry media biofilter. It will still be experimental in large scale applications. However, it can reduce at least 80 to 90% of nitrogenous and sulfurous compounds. 5.2.3 treatment
The LTB is a new development stemmed from the composite liner LBR. The results indicate that it is an advance system of managing highly polluting . In order to ensure application of known and best practices, an ASP has been incorporated in the treatment system. The final treatment in the constructed wetland will ensure discharges that will comply with CEA water quality standards. The harvesting regime of the cattail (Typha latifolia) is an important management practice to remove heavy metals (Sasikala S.etal.,2005). There will always be some traces of accumulated heavy metals as given Chapter 3, which will be washed out with time. In order to prevent high temperature water discharges from the closed looped system directly to the River, it will be mixed in the ASP to improve the process and dilute the effluents, which will eventually be sent to the Constructed Wetlands. The design capacity of the wetland has been increased to accommodate increased flows. The efficiency of heavy metal uptake will increase at high growth rates of cattails. 5.2.4 Safe disposal of sewage and sludge waste
As mentioned in chapter 4, mixing sewage with in the ASP is an efficient management practice. The disposal of sludge is the main concern of such practices. Therefore, the additional lands that will be given in the new lease agreement will be used to construct lined pits with the composite liner system and the sludge buried with a good soil cover. These pits could be dug in the River reservation where the houses would be vacated. It is suggested to plant trees to uptake the heavy metals and nutrients from these sludge. Similar pits have been dug and when examined it was found that the root systems have invaded the pits and thriving well. Also a study is underway to extract phosphate from sludge. 5.2.5 Management of residue wastes to prevent possible impacts
The point source separation progamme that will be introduced will drastically eliminate such wastes being deposed in LFB. The MRF will be functional for sorting and separating new wastes that are hazardous. A temporary landfill will be constructed as marked in the layout plan for any of the wastes that will be permanently disposed once the dumpsite is mined and isolated from the LFB. Double liner system will be used in the temporary and permanent landfills. The dischages from these landfills will be treated in the ASP and finally in the Constructed Wetland 5.2.6 Management of hazardous wastes
A management system is required to tackle the problems of hazardous waste arising from rehabilitation of dumpsite. Also, it is essential to ensure a well developed e-waste management unit within the MRF. The estimated quantities are considerable, amounting to 1647 tonnes of wastes from the dump and about 1018 tonnes in 2010. The actual ewastes may be 20 to 40 % of the total estimated. It is suggested to store these wastes and then finally dispose them when the mining operation of the dumpsite is completed. The best possible option is to concrete these materials covered in polyethylene bags. The long term solution is to recover the materials from e-wastes and it is a lucrative solution to the present problems of managing them. The technologies are available, but they are under patents. The immerging trend of „by back‟ option is the ethical way out, thus promoting the use of less harmful materials. Nevertheless, these solutions are in the infant stages or in the incubation period to be materialized in the near future. There are several categories of waste materials that are hazardous, but they can be assimilated to provide an ecological solution. Like the sludge, it can be safely disposed in secure landfill pits which can be isolated from surface and subsurface flow. The evasive measure is based on the concept of constructing composite liner system which prevents from excessive permeation of heavy metals. The study conducted on adsorption properties of the soils indicate greater possibilities of harnessing such mechanisms manifested by the existing soils for beneficial purposes. The use of plants and trees grown on these pits can take up the nutrients over number of years. The layout of the system is shown in detail in Figure……. 5.2.7 Impacts on flora and fauna
The use of waste to produce electricity would result in the reduction of waste accumulated in the area. The restoration of the site will also help to establish the characteristic faunal and floral components that could be seen in a Kandyan Home Garden system, which is the typical vegetation in the area, instead of the invasive plants that dominate because of waste dumping. Therefore, it is recommended that, opening up of lands for development activities should be done to the bare required minimum. In future, all lands that are not used for civil constructions or physical infrastructure need to be rehabilitated to maintain a good forest cover with native trees or plants that have no adverse impacts on flora - on site as well as away from the site. It is suggested that the project area needs to be surrounded by a protective vegetation belt that can prevent noise pollution from the power plant other machinery, most importantly, discourage spread of invasive species and protect the site from land degradation. The gardeners will be trained to suppress invasive species and encourage native habitats to thrive for developing a conducive ecosystem for humans, fauna and flora.
CHAPTER 6 CONTINGENCY PLAN The breakdowns of the waste handling bulldozers are frequent operating in most MSW dumpsites and landfills. The wear and tear is very high with the wastes that have corrosive action and particles having diverse physical and chemical properties. In order to reduce breakdowns of vehicles and machinery, a more frequent servicing schedule than recommended should be adhered to ensure low repair and maintenance costs. A standby dozer, even an old one, perhaps is best to replace the company owned machine. It could even be a replacement dozer supplied by the Municipality. The best practices of daily cleaning and maintenance of the track is vital. Ideally, a waste handler should be used to prevent frequent breakdowns of the track. Such machines are bulky for the project in Kandy; instead guards can be fixed to the bulldozer track and a baton just above and across the track to remove entangling waste materials. There could be number of breakdowns of the MRF. It is very susceptible to jamming routine systems operations, so that adequate storage facility should be available to buffer the shortcomings. The MRF should be designed and operated to clear the accumulating wastes. A large floor area is required to stock the wastes in containers that can be stacked one over the other. There should be number of parallel activities so that human and other available resources can be used effectively. The power plant will have two 5MW generators, each independent in waste loading, gasification, boiler, steam turbine and generator. Therefore, frequent maintenance can be done by shutting down one at a time. Both can be shut down as well when power is in excess. There are times when the power plant can be operational, but there are problems of substation, distribution lines etc., thus compelling stoppages of electricity generations. Under such circumstances, the excess gas is stored and utilized directly in secondary combustion or flared to meet air emission standards. The system of disposal will not be hampered since LBR can be operational under most weather conditions. However, there could be occasions when the weather conditions are adverse for disposing the wastes. Therefore, it is best to have a moveable covered structure like in…. and even have a conveyor to lift and place the wastes in the required cell, so as to reduce the number of roads constructed inside the landfill, thus reduce the use of bulldozer and the need for collection vehicles hauling the wastes inside the LBR. These suggestions may sound too advanced, but the company‟s objective is to find novel approaches to reduce costs in the long term. In fact, it will eliminate the use of soil in the LBR, since the daily cover will be compost materials, derived from mining. Also it will make the mining activity easier to produce high quality RDF. In the event of a fire in the LFB, the irrigation system will activate and if the fire persists, the clay found in the site can be diluted with water to inject the slurry inside the burning cavities within the waste, inside the LBR. In order to prevent excessive cracking of the top cover under dry conditions, again the irrigation system play a major role in the application of required quantity of water to have gas tight conditions.
There is always safety and fire prevention regulations to be adopted in the power plant. There are number different units within the power plant to prevent and ensure dousing of local fires within those units. Naturally, all of the different types of fire extinguishers will be serviced regularly to comply with the CEA, KMC, Harispathuwa PS and the insurance company fire drills conducted to ensure safety of personnel and protection of power plant from any dangers. It is unlikely to have floods, but in the event that there could be an event, the power plant will be built above the maximum flood level of ………Only the Constructed Wetland will be affected in unlikely occurrence of a flood.
CHAPTER 7 MONITORING PLAN
7.1 Background
The Project Proponent Eco tech Lanka Limited necessitates to conduct a comprehensive environmental monitoring programme of the different segments of the environment within the project site and the vicinity of the project site. This is imperative to assess the performance or success of the implemented mitigation measures. There are three basic environmental monitoring tasks to assess the success of mitigation and identifying residual impacts as follows. i. Pre-construction monitoring to determine the baseline conditions in detail to identify impacts and mitigation measures and costs to respond to CEA conditions of approval. ii. Construction compliance monitoring, and iii. Post construction monitoring of maintenance and operational project activities including surface water quality, groundwater quality, air quality and noise level baseline conditions. It should be noted that during the construction phase both the contractor and the Project Proponent will take the major responsibility in undertaking the monitoring aspects with assistance from SWMRU, Department of Agricultural Engineering, University of Peradeniya. Further, the SWMRU will undertake environmental management issues, monitoring aspects and implementation of mitigation measures to prevent environmental pollution. In addition to that, ISWMS Monitoring Committee will be established for the following purposes; i. To ensure the ISWMS operation in compliance with the conditions stipulated by authorities and the ISWMS‟s operation manual and ii. To keep the transparency of the ISWMS operation. The proposed ISWMS monitoring committee will comprise of representatives from various organizations and individuals as described in Table 7.1. The chairperson of the monitoring committee should be appointed at the first committee meeting. He/she is responsible for executing the routine monitoring activities that described in section 7.2 and should take the responsibility of reporting the status of the ISWMS to the relevant parties.
Table 7.1 Members of the proposed ISWMS Monitoring Committee Organization
Nominee
Eco Tech Lanka ltd
The Chairman/Technical Director Manager Site Engineer(s) Site Manager Environmental Executive Site Supervisor(s)
SWMRU
Research Associate Research Assistant(s)
CEA
Environmental Officers
Central Provincial Council
Officer (s)
KMC
Commissioner Chief Engineer Head, solid waste management division PHI (s) (public health inspectors)
CEB
Electrical Engineer (s)
NWS&DB
Engineer (s)
Mahaweli Development Authority
Engineer (s)
Divisional Secretariat Office - Harispaththuwa
Grama Niladari- Project area Samurdhi Niyamaka- Project area Environmental Officer
Harispaththuwa Pradeshiya Sabha
Environmental Officer Public Health Inspector
Non Government Organizations (NGO‟s)
Representatives from local NGO‟s
Community representatives
Clergy of the nearest religious organization Representative(s) from Community Based Organizations A representative from a Women‟s organization in the neighborhood Representatives(s) from neighboring villages Representative (s) from resettlers
7.2 ISWM Monitoring Plan 7.2.1 Quantity and Quality testing of incoming solid waste
Table 7.2 presents the monitoring plan quantity and quality testing of incoming solid waste.
7.2 Quantity and quality testing of incoming solid waste
Monitoring objective Parameters monitored
to
In order to avoid unauthorized waste such as clinical and hazardous waste entering the facility
be Weight of the all the incoming waste, fast and slow biodegradable fraction, moisture content, bulk density, temperature, pH and volatile solids
Monitoring Locations
At the weighbridge area
Frequency
Daily
Responsible Agency For monitoring work: Site supervisors with the For monitoring work assistance of SWMRU, University of Peradeniya For Supervision: Eco tech Lanka Limited, ISWMS monitoring committee For Communication: Submission of report by monitoring agency and reporting the same to CEA and ISWMS monitoring committee by Eco tech Lanka Limited. 7.2.2 Meteorology
In order to monitor the prevailing climatic conditions of the project site a meteorological station will be installed at the selected location of the project site (see layout plan Figure ..). The meteorology monitoring plan is given in Table 7.3.
Table 7.3 Meteorology monitoring plan
Monitoring objective
To monitor the prevailing climatic conditions of the project site
Parameters to be monitored
Precipitation, Maximum and Minimum Temperature, Relative Humidity, Pan evaporation, wind speed and direction
Monitoring Locations
The location given in Figure …..
Frequency
Continuously throughout the each day
Responsible Agency For monitoring work
For monitoring work: Site supervisors with the assistance of SWMRU, University of Peradeniya For Supervision: Eco tech Lanka Limited, ISWMS monitoring
committee, Meteorological Department, (Katugastota or Ganoruwa) For Communication: Submission of report by monitoring agency and reporting the same to CEA and ISWMS monitoring committee by Eco tech Lanka Limited and Meteorological Department (Katugastota or Ganoruwa) 7.2.3. Hydrology
The hydrology monitoring plan is given in Table 7.4. Table 7.4: Hydrology monitoring plan a. Construction Phase
Monitoring objective Parameters to be monitored Monitoring Location Frequency
Responsible Agency For monitoring work
To prevent erosion of the fill material and excess erosion of slopes and waterways with corresponding silting of the eroded soil into the low lying marshy area and Mahaweli river Water table, Water levels, flow rate of surrounding streams , pH value, Sulfate content, Iron Content, Heavy metals Sediment level and Suspended solids The location given in Figure ….. According to climatic conditions of the area and schedule of construction. For monitoring work: SWMRU, University of Peradeniya For Supervision: Eco tech Lanka Limited, ISWMS monitoring committee For Communication: Submission of report by monitoring agency and reporting the same to CEA and ISWMS monitoring committee by Eco tech Lanka Limited
b. Operational Phase
To prevent erosion of the fill material and excess erosion of Monitoring objective slopes and waterways with corresponding silting of the eroded soil into the low lying marshy area and Mahaweli river Records of rainfall pattern/seasons, Records of flood levels Parameters to be stability of vegetation cover after construction. Functions of monitored constant surveillance programs as part of routine maintenance. The embankment surrounding the proposed landfill site. Also Monitoring the canals and culverts necessary to be constructed, the Locations existing water bodies Before and during rainy seasons Frequency For monitoring work: SWMRU, University of Peradeniya For Supervision: Eco tech Lanka Limited, ISWMS monitoring Responsible Agency committee For monitoring work For Communication: Submission of report by monitoring agency and reporting the same to CEA and ISWMS monitoring committee
by Eco tech Lanka Limited
7.2.4 Surface water quality monitoring plan
Table 7.5 presents the environmental monitoring plan for surface water quality.
Table7.5: Surface Water Monitoring Plan
Monitoring objective
Parameters to be monitored
Monitoring Locations
Frequency
Responsible Agency
Pre-construction phase:To determine baseline (existing) conditions on surface water quality Construction phase: To avoid contamination of water by construction and related activities Operational phase:To ensure existing water sources will not be spoilt during the operational phase
pH, turbidity, electrical conductivity, total and faecal coliform levels and chemical parameters such as TS,VS,TSS,VS TDS, COD, BOD5, DO, oil & grease, TN, NH4-N, NO 2-, NO3-, TP and various heavy metals such as Pb, Zn, Cd, Cr, Hg The results should be assessed with reference to the CEA stipulated standards. Surrounding streams, upstream, downstream and effluent discharge point at the Mahaweli river, wastewater collecting ponds. Once a month (The monitoring frequency should be varied and in wet season more frequent sampling should be undertaken) For monitoring work: SWMRU, University of Peradeniya For Supervision: Eco tech Lanka Limited, ISWMS monitoring committee For Communication: Submission of report by monitoring agency and reporting the same to CEA and ISWMS monitoring committee by Eco tech Lanka Limited
7.2.5 Ground water quality monitoring plan
Table 7.6 presents the environmental monitoring plan for surface water quality.
Table 7.6: Groundwater monitoring plan
Monitoring objective
Parameters to be monitored
Monitoring Locations Frequency
Responsible Agency
Pre-construction phase:To determine baseline (existing) conditions on ground water quality Construction phase: To avoid contamination of water by construction and related activities Operational phase: To avoid groundwater quality deterioration arising due to Depth of groundwater, pH, salinity, electrical conductivity, turbidity, total and faecal coliform levels and chemical parameters such as total hardness, total alkalinity, Fe, Cl,SO42-, TSS, TDS, COD, BOD5, DO, oil & grease, TN, NH4-N, NO2-, NO3-, TP and a variety of heavy metals such as Pb, Hg, As, Cd, Cr, Cu, Ni and Zn, etc.
Existing wells which are located adjacent to the project site, bore holes given in Figure … Once a month (The monitoring frequency should be varied and in wet season more frequent sampling should be undertaken) For monitoring work: SWMRU, University of Peradeniya For Supervision: Eco tech Lanka Limited, ISWMS monitoring committee For Communication: Submission of report by monitoring agency and reporting the same to CEA and ISWMS monitoring committee by Eco tech Lanka Limited
7.2.6 Sediment quality
In addition to water quality monitoring, the soil and sediment quality of the natural marshy should also be monitored mainly with reference to heavy metals. The sediment quality monitoring plan is given in Table 7.7.
Monitoring objective
Pre-construction phase: To determine baseline (existing) conditions on sediment quality in the existing water b odies Operational phase: To avoid sediment quality deterioration arising due to unavoidable
circumstances such as malfunctioning of the wastewater treatment plant and subsequent bioaccumulation scenarios
Parameters to be monitored
Heavy metals such as As, Zn, Hg, Pb, Cd, Cr and Ni.
Monitoring Locations
pH, CEC Existing wells which are located adjacent to the project site, bore holes given in Figure …
Frequency
Once in 3 months
Responsible Agency
For monitoring work: SWMRU, University of Peradeniya For Supervision: Eco tech Lanka Limited, ISWMS monitoring committee For Communication: Submission of report by monitoring agency and reporting the same to CEA and ISWMS monitoring committee by Eco tech Lanka Limited
7.2.6 Monitoring of treatment
It will include all the measurements and parameters given for surface and groundwater, such that the performance of individual treatment units and the entire system will be evaluated and reported. 7.2.7 Monitoring of emissions from the power plant
The monitoring systems and plans are still to be finalized by the manufacturers. However, NOx, SOx, CO and PM will be monitored before and after controlling flue gas quality and at the point of emissions. The company will be responsible to provide all the equipment for monitoring the ambient air quality in the specified locations derived from the effected areas that will be finalized after the ambient air quality measurements are completed. It will include locations stipulated by the CEA.
