3R CONCEPT
In a developing country as China, the research in the field of renewable and clean energy, such as PV technology, is still undergoing the preliminary stage. Furthermore, the process from manufacturing to end-of-life disposal of the PV modules must satisfy the regulations of environment protection. Considering a durable deve loping strategy to Cd-based PV modules, this letter presents a recycling method of design based on Green 3R-concept, namely, Reducing products cost, Reusing materials, and recycling products. Therefore, a fine cycling economic development based on resource renewal for benign green environment will be established, and enhance the commercial progress of the Cd-based PV technology. Waste hierarchy:
The waste hierarchy refers to the 3Rs of reduce, of reduce, reuse and recycle, recycle, which classify waste management strategies according to their desirability. The 3Rs are meant to be a hierarchy, in order of importance. The waste hierarchy has taken many forms over the past decade, but the basic concept has remained the cornerstone of most waste minimisation strategies. The aim of the waste hierarchy is to extract the maximum practical benefits from products and to generate the minimum amount of waste. 3R’s: Reduce - to buy less and use less. Incorporates common sense ideas like turning off the lights, rain barrels, and taking shorter showers, but also plays a part in Composting/Grass cycling (transportation energy is reduced), low-flow toilets, and programmable thermostats. Includes the terms Re-think, Precycle, Carpool, Efficient, and Environmental Footprint/Food print. Reuse - elements of the discarded item are used again. Initiatives include Hand-Me-Downs, Garage Sales, Quilting, and Composting (nutrients). Includes the terms Repair, Regift, and Up cycle. Recycle - discards are separated into materials that may be incorporated into new products. This is different from Reuse in that energy is used to c hange the physical properties of the material. Initiatives include Composting, Beverage Container Deposits and buying products with a high content of post-consumer material. Generate - capturing useful material for waste to energy programs. Includes Methane Collection, Gasification and Digestion, and the term Recover. Incinerate - high temperature destruction of material. Differs from Gasification in that oxygen is used; differs from burning in that high temperatures consume material efficiently and e missions are controlled.
Devastate - to discard into the natural environment, or to "trash" the planet. Includes Litter, Burn Barrels, Unnecessary Vehicle Idling, and Dumping discards onto land or into water.
REDUCE:
Waste minimisation is the process and the policy of reducing the amount of waste produced by a person or a society. Waste minimisation involves efforts to minimize resource and energy use during manufacture. For the same commercial output, usually the fewer materials are used, the less waste is produced. Waste minimisation usually requires knowledge of the production process, cradle-to-grave analysis (the tracking of materials from their extraction to their return to earth) and detailed knowledge of the composition of the waste. In industries, using more efficient manufacturing processes and better materials will generally reduce the production of waste. The application of waste minimisation techniques has led to the development of innovative and commercially successful replacement products. Waste minimisation has proven benefits to industry and the wider environment.
There are government incentives for waste minimisation, which focus on the environmental benefits of adopting waste minimisation strategies. In the UK , several pilot schemes such as The Catalyst Project and the Dee Waste Minimisation Project, have shown the efficacy of such policies. Fourteen companies in Merseyside took part in the Catalyst Project; the project generated overall savings of £9 million and landfill waste was reduced by 12,000 tonnes per year. The following is a list of waste minimisation processes: •
Resource optimization.
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Reuse of scrap material.
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Improved quality control and process monitoring.
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Waste exchanges.
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Ship to point of use.
The amount of waste an individual produces is a small portion of all waste produ ced by society, and personal waste reduction can only make a small impact on overall waste volumes. Yet, influence on policy can be exerted in other areas. Increased consumer awareness of the impact and power of certain purchasing decisions allows industry and individuals to change the total resource consumption. Consumers can influence manufacturers and distributors by avoiding buying products that do not have eco-labeling, which is currently not mandatory, or choosing products that minimize the use of packaging. In the UK , Pull Apart combines both environmental and consumer packaging surveys, in a kerbside packaging recycling classification
system to waste minimize. Where reuse schemes are available, consumers can be proactive and use them. REUSE:
To reuse is to use an item more than once. This includes conventional reuse where the item is used again for the same function, and new-life reuse where it is used for a new function. In contrast, recycling is the breaking down of the used item into raw materials which are used to make new items. By taking useful products and exchanging them, without reprocessing, reuse help save time, money, energy, and resources. In broader economic terms, reuse offers quality products to people and organizations with limited means, while generating jobs and business activity that contribute to the economy. The classic example of conventional reuse is the doorstep delivery of milk in refillable bottles; other examples include the retreading of tires and the use of reusable plastic boxes (transit packing) instead of single-use cardboard cartons.
Advantages & disadvantages
Reuse has certain potential advantages: •
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Energy and raw materials savings as replacing many single use products with one reusable one reduces the number that need to be manufactured. Reduced disposal needs and costs. Refurbishment can bring sophisticated, sustainable, well paid jobs to underdeveloped economies. Cost savings for business and consumers as a reusable product is often cheaper than the many single use products it replaces. Some older items were better handcrafted and appreciate in value.
Disadvantages are also apparent: • •
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Reuse often requires cleaning or transport, which have environmental costs. Some items, such as Freon appliances or infant auto seats, could be hazardous or less energy efficient as they continue to be used. Reusable products need to be more durable than single-use products, and hence require more material per item. This is particularly significant if only a small proportion of the reusable products are in fact reused. Sorting and preparing items for reuse takes time, which is inconvenient for consumers and costs money for businesses.
Examples: a) Reuse centers & virtual exchanges.
b) Remanufacturing. c) Deposit programs. d) Refilling programs. e) Waste exchanges.
Comparison to recycling
Recycling differs from reuse in that it breaks down the item into raw materials which are then used to make new items, as opposed to reusing the intact item. As this extra processing requires energy, as a rule of thumb reuse is environmentally preferable to recycling ("reduce, reuse, recycle"), though recycling does have a significant part to play as it can often make use of items which are broken, worn out or otherwise unsuitable for reuse. However, as transport emissions are significant portion of the environmental impact of b oth reuse and recycling, in some cases recycling is the more prudent course as reuse can require long transport distances. A complex life cycle analysis may be required during a products design phase to determine the efficacy of reuse, recycling, or neither, and produce accordingly. Reuse of information
Besides the great amount of reuse of our physical resources, there is now a powerful argument for reuse of information, notably program code for the software that drives computers and the Internet, but also the documentation that explains how to use every modern device. And it is proposed as a way to improve education by assembling a great library of shareable learning objects that can be reused in learning management systems. Software reuse grew out of the standard subroutine libraries of the 1960s. It is the main principle of today's object-oriented programming. Instead of constantly reinventing software wheels, programming languages like C++, Java, Objective C, and others are building vast collections of reusable software objects and components. Reuse is closely related to the concept of single source publishing in which text written once is output to multiple publishing channels like print, the web, mobile devices, and online help. Reuse of information always has a single source, but not all single-sourced information is reused in multiple different contexts. Reuse of information has a tremendous return on investment for organizations whose documentation is translated into many languages. Translation memory systems can store text that has already been translated into dozens of languages for retrieval and reuse. RECYLING Recycling involves processing used materials (waste) into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, reduce energy usage, reduce air pollution (from incineration) and water pollution (from land filling) by reducing the
need for "conventional" waste disposal, and lower greenhouse gas emissions as compared to virgin production. Recycling is a key component of modern waste reduction and is the third component of the "Reduce, Reuse, Recycle" waste hierarchy. Recyclable materials include many kinds of glass, paper , metal, plastic, textiles, and electronics. Although similar in effect, the composting or other reuse of biodegradable waste – such as food or garden waste – is not typically considered recycling. Materials to be recycled are either brought to a collection center or picked up from the curbside, then sorted, cleaned, and reprocessed into new materials bound for manufacturing. In a strict sense, recycling of a material would produc e a fresh supply of the same material—for example, used office paper would be converted into new office paper, or used foamed polystyrene into new polystyrene. However, this is often difficult or too expensive (compared with producing the same product from raw materials or other sources), so "recycling" of many products or materials involve their reuse in producing different materials (e.g., paperboard) instead. Another form of recycling is the salvage of certain materials from complex products, either due to their intrinsic value (e.g., lead from car batteries, or gold from computer components), or due to their hazardous nature (e.g., removal and reuse of mercury from various items). Critics dispute the net economic and environmental benefits of recycling over its costs, and suggest that proponents of recycling often make matters worse and suffer from confirmation bias. Specifically, critics argue that the costs and energy used in collection and transportation detract from (and outweigh) the costs and energy saved in the production process; also that the jobs produced by the recycling industry can be a poor trade for the jobs lost in logging, mining, and other industries associated with virgin production; and that materials such as paper pulp can only be recycled a few times before material deg radation prevents further recycling. Proponents of recycling dispute each of these claims, and the validity of arguments from both sides has led to enduring controversy. Early recycling
Recycling has been a common practice for most of human history, with recorded advocates as far back as Plato in 400 BC. During periods when resources were scarce, archaeological studies of ancient waste dumps show less household waste (such as ash, broken tools and pottery)— implying more waste was being recycled in the absence of new material. In pre-industrial times, there is evidence of scrap bronze and other metals being collected in Europe and melted down for perpetual reuse. In Britain dust and ash from wood and coal fires was collected by 'dustmen' and down cycled as a base material used in brick making. The main driver for these types of recycling was the economic advantage of obtaining recycled feedstock instead of acquiring virgin material, as well as a lack of public waste removal in ever more densely populated areas. In 1813, Benjamin Law developed the process of turning rags into 'shoddy' and 'mungo' wool in Batley, Yorkshire. This material combined recycled fibres with virgin wool. The West Yorkshire shoddy industry in towns such as Batley and Dewsbury lasted from the early 1800s to at least 1914.
Publicity photo for US aluminum salvage campaign in 1942 Industrialization spurred demand for affordable materials; aside from rags, ferrous scrap metals were coveted as they were cheaper to acquire than was virgin ore. Railroads both purchased and sold scrap metal in the nineteenth century, and the growing steel and automobile industries purchased scrap in the early twentieth century. Many secon dary goods were collected, processed, and sold by peddlers who combed dumps, city streets, and went door to door looking for discarded machinery, pots, pans, and other sources of metal. By World War I, thousands of such peddlers roamed the streets of American cities, taking advantage of market forces to recycle post-consumer materials back into industrial production.
Wartime recycling
Resource shortages caused by the world wars, and other such world-changing occurrences greatly encouraged recycling. Massive government promotion campaigns were carried out in World War II in every country involved in the war, urging citizens to donate metals and conserve fibre, as a matter of significant patriotic importance. Resource conservation p rograms established during the war were continued in some countries without an abundance of natural resources, such as Japan, after the war ended. Post-war recycling
The next big investment in recycling occurred in the 1970s, due to rising energy costs. Recycling aluminum uses only 5% of the energy required by virgin production; glass, paper and metals have less dramatic but very significant energy savings when recycled feedstock is used. The first recycling mill was Waste Techniques, built in Conshohocken, Pennsylvania in 1972. Waste Techniques was sold to Frank Keel in 1978, and resold to BFI in 1981. Woodbury, New Jersey was the first city in the entire United States to mandate recycling. Led by Rose Rowan in the early 1970s, the idea of towing a "recycling" trailer behind a waste management vehicle to enable the collection of trash and recyclable material at the same time emerged. Other towns and cities soon followed suit, and today many cities in the U.S. make recycling a requirement. In 1987, the Mobro 4000 barge hauled garbage from New York to North Carolina; where it was denied. It was then sent to Belize; where it was denied as well. Finally, the barge returned to New York and the garbage was incinerated. The incident led to heated discussions in the media about waste disposal and recycling. The incident is often referred to as igniting the recycling "hysteria" of the 1990s.
Common recyclables
Many different materials can be recycled but each type requires a different technique. Aggregates and concrete
Concrete block: Concrete aggregate collected from demolition sites is put through a crushing machine, often along with asphalt, bricks, dirt, and rocks. Smaller pieces of concrete are used as gravel for new construction projects. Crushed recycled concrete can also be used as the dry aggregate for brand new concrete if it is free of contaminants. This reduces the need for other rocks to be dug up, which in turn saves trees and habitats .
Batteries: Some batteries contain toxic heavy metals, making recycling or proper disposal a high priority. The large variation in size and type of batteries makes their recycling extremely difficult: they must first be sorted into similar kinds and each kind requires an individual recycling process. Additionally, older batteries contain mercury and cadmium, harmful materials which must be handled with care. Because of their potential environmental damage, proper disposal of used batteries is required by law in many areas. Unfortunately, this mandate has been difficult to enforce. Lead-acid batteries, like those used in automobiles, are relatively easy to recycle and many regions have legislation requiring vendors to accept used products. In the United States, the recycling rate is 90%, with new batteries containing u p to 80% recycled material. Glass:
Public glass waste collection point for separating clear, green and amber glass. Glass bottles and jars are gathered by a curbside collection truck and bottle banks, where the glass may be sorted into color categories. The collected glass cullet is taken to a glass recycling plant where it is monitored for purity and contaminants are removed. The cullet is crushed and added to a raw material mix in a melting furnace. It is then mechanically blown or molded into new jars or bottles. Glass cullet is also used in the construction industry for aggregate and glassphalt. Glassphalt is a road-laying material which comprises around 30% recycled glass. Glass can be recycled indefinitely as its structure does not deteriorate when reprocessed 4th R:
Some waste management experts have recently incorporated a 'fourth R': "Re-think", with the implied meaning that the present system may have fund amental flaws, and that a thoroughly
effective system of waste management may need an entirely new way of looking at waste. Source reduction involves efforts to reduce hazardous waste and other materials by modifying industrial production. Source reduction methods involve changes in manufacturing technology, raw material inputs, and product formulation. At times, the term "pollution prevention" may refer to source reduction. Another method of source reduction is to increase incentives for recycling. Many communities in the United States are implementing variable rate pricing for waste disposal (also known as Pay As You Throw - PAYT) which has been effective in reducing the size of the municipal waste stream. Source reduction is typically measured by efficiencies and cutbacks in waste. Toxics use reduction is a more controversial approach to source reduction that targets and measures reductions in the upstream use of toxic materials. Toxics use reduction emphasizes the more preventive aspects of source reduction but, due to its emphasis on toxic chemical inputs, has been opposed more vigorously by chemical manufacturers. Toxics use reduction programs have been set up by legislation in some states, e.g., Massachusetts, New Jersey and Oregon. CONCLUSION:
From energy consumption pattern in the campus it is clear that offices consume more than 50% of the total energy. The rest are residential areas 15%, Chiller room 10%, etc. Residential areas are the major source of water consumption; with around 50%. The second source is the offices, almost 25% of total water consumption. The rest are chiller room, regional experimental center, etc. On an average, the wastewater generation from AIT is about 1,122 m3/day. The water balance indicates a lost of 17.3%. The physical characteristics of influent and effluent of wastewater treatment plant indicates that BOD removal efficiency is only 68-71%. Compared to the Thai standard for wastewater, AIT’s WWTP sometimes cannot meet the standard. Each day AIT generates about 2 tons of domestic waste of which only 4% is recyclable. The remaining 96% is sent directly to the landfill. Seventy five percent o f the total recyclable waste is contributed by paper mostly from the offices. Solid waste generation is largely from the residential areas; especially the staff areas; about 32% of total solid waste. Student areas generate 27%, 17% from the offices and the rest are AITCC, cafeteria and others. Organic waste is estimated at 60% of total waste. Energy, w ater and solid waste audits were conducted at the representative buildings which consume large amount of energy, water and generate huge amount of solid waste. Yard waste is about 0.2 tons per day, some of them are sent to the organic composting site in the AIT campus. The rest is dumped at the dumping site near the School of Management. After identifying the potential sources of en ergy and water consumption and solid waste generation, CP op tions are proposed, to suggest measures to reduce energy and water consumption and solid waste generation. If AIT implemented these CP options, the daily energy consumption will be reduced from 9.65 kWh/person to 7.65 kWh/person by 2010. Moreover, the daily water consumption in 2010 will be reduced from 354 L/person to 226 L/person.
