HAZARDOUS WASTES ~Defnition~ s ubstantial danger, danger, now or Any waste or combination of waste that poses substantial in the future; to human, plant and animal life.
Classified as hazardous based on four characteristics: Ignitability (flammable) eacti!ity Corrosi!ity "o#icity It must be $A%&'& or &I*+& + with special precaution
our basic characteristics: Ignitable (flash point of - /oC ) eacti!e (unstable or undergoes rapid or !iolent chemical reaction
with water, air or other materials) Corrosi!e (dissol!es metals, burns the s0in or has a p$ - 1 or ph2
31.4) "o#ic (poisonous or can cause cancer, mutations or death)
Physical state of Hazardous waste 5 6as, olid, 'i7uid MALAYSIAN LEGISLATION n!ironmental Act 389 .. (&io#in and uran) egulations 1// . (chedule
ENVIONMENTAL !"ALITY A#T The Department of Environment (DOE) is empowered under the
Environmental Quality Act 197 to control and prevent pollution and to protect and enhance the !uality of the environment"
A set of re#ulations dealin# with ha$ardous waste mana#ement which
re#ulate the stora#e% transport% treatment and disposal of ha$ardous wastes was enforced on &ay 19'9 >Environmental Quality (cheduled *astes) +e#ulations 19'9 >Environmental Quality (cheduled *astes) +e#ulations ,--. >Environmental Quality (cheduled *astes) (Amendment) +e#ulations ,--7 >Environmental Quality (Dio/in And 0uran) +e#ulations ,--. >Environmental Quality (rescri2ed remises) (cheduled *astes Treatment and Disposal 0acilities) +e#ulations and >Environmental Quality (rescri2ed remises) (cheduled *astes Treatment and Disposal 0acilities) Order% 19'9 S#HE$"LE$ %ASTES EG"LATIONS +e#ulations specify
>3efore disposal% 2e rendered innocuous >*astes #enerated shall 2e reduced >4enerators notify DOE >*astes #enerated stored% recovered 5 treated on6site >and farmin#% incineration% disposal% o86site recovers% stora#e and treatment% 2y DOE licensed premises >*aste containers clear la2el% proper% ade!uate
>4enerators shall o2ey the re!uirement of consi#nment note system when transportin#
1-7 cate#ories under chedules *astes #rouped into , parts
>art 1 6 cheduled *astes from :on peci;c ources e"#" mineral oil from machines% spent oil% oil tanart , 6 cheduled *astes from peci;c ources e"#" mineral oil from re;nery% oil slud#e from wor
practica2le means= *aste #enerators to notify the DOE of any scheduled wastes #enerated
and
premises of a waste #enerator= and farmin#% incineration% disposal% o86site recovery% o86site stora#e and
o86site treatment shall only 2e carried out at prescri2ed premises licensed 2y the DOE= >se of dura2le waste containers with clear la2els" tora#e of wastes shall
2e proper and ade!uate=
*aste #enerators shall conform to the re!uirements of the consi#nment
note system when transportin# wastes to ensure it reaches the approved destination and are carried out 2y licensed transporters (refer to Anne/ ?)=
*aste #enerators shall provide information to a transporters re#ardin# the
nature of the wastes transported and action to 2e ta
$IO&IN AN$ '"AN EG"LATIONS ())*
+e#ulations #a$etted ,. &arch ,-- +e#ulations e8ective date 1 &ay ,-- arameter to control Dio/in dan 0uran These re#ulations apply to facilities
1) &unicipal solid wastes incinerator ,) cheduled waste incinerator ?) ulp or paper industry slud#e incinerator ) ewa#e slud#e incinerator :ew 0acility
>@ompliance date 1 &ay ,-- onwards >@oncentration limit for air emission of Dio/in and 0uran -"1 nano#ram:m? TEQ E/istin# 0acility
>@ompliance Date 1 &ei ,-- 6 ?- April ,--7 >@oncentration limit for air emission of Dio/in and 0uran as prescri2e in their licenseapproval or the approved conditions stated in the environment impact assessment report >@ompliance date 1 &ay ,--7 onwards >@oncentration limit for air emission of Dio/in and 0uran -"1 nano#ram:m? TEQ OTHE LEGISLATIONS 3asel @onvention6 Technical 4uideline on the Environmentally ound
&ana#ement of 3iomedical and Bealthcare *aste"
&inistry of Bealth &alaysia% &ana#ement of @linical and +elated *astes in
Bospital and Bealth @are Esta2lishments% 199?
What are the useful methods of Hazardous Waste Management ? Hazardous wastes have become an important environmental and public health issue which concerns many countries in the world. In the modern framework of hazardous waste management, a four pronged strategy has been adopted: 1.
Minimizing the uantity of waste
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"ecycling of industrial waste
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$reatment of the waste
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&ollection, transport and disposal of waste in an environmentally sound manner.
'll four of these approaches are important and are not e(clusive of each other. )hen dealing with a given hazardous waste problem, often there is a need to utilise a combination of the four general approaches outlined above. )e will discuss, in brief, each of these four approaches.
Waste Minimization $he first priority in hazardous waste management is to reduce the uantity of waste to minimum. $hree ma*or waste reduction schemes which are often used can be summarized as below: i) Process Modification: +ften the industrial process can be altered in such a way that the use of raw materials is optimized and the amount ofhazardous waste is reduced to barest minimum. -or e(ample, in zinc electroplating, the sulphate salt is substituted by the chloride compound with slight modification of the process this can eliminate the cyanide problem. ii) Waste Concentration : $he waste can be concentrated using evaporation, precipitation or decantation techniues which means that the volume of waste can be considerably reduced using these methods. Incineration, viz., o(idation of inflammablewaste is often practiced in order to reduce the volume of waste to be handled. It is an e(cellent method of waste disposal, but the cost of operation usually e(ceeds the net gains. iii/ Waste Segregation : 0egregating the hazardous waste streams from nonhazardous streams decreases the volume of hazardous wastes, thus, making it easier to treat.
Recycling Industrial Wastes
Many substances in refuse wastes have value. $hey include glass, wood fibre from paper products, and metal. 0cientists have developed ways of recycling many wastes so they can be used again. 'lmost all materials are recyclable. However, in some more energy will be e(pended in recovery than the recovered value warrants. $he two broad ways of processing hazardous waste are waste reuse and waste recycling. )e shall briefly deal with them. i) Waste Reuse: In some cases waste material can be used as a raw material with very little processing. $ransfer of the waste as is without reprocessing, to another facility is known as waste reuse or waste e(change. 2nwanted materials of commence such as outdated chemicals or untested materials not meeting the high uality control reuirements of purchasing industry, can be reused without processing. 3rocess wastes such as cardboard for making paper pulp, copper or other metal salt solutions for metal recovery, oils that can be used as fuels. $his includes a variety of other materials that can be reused as industrial feed stocks. ii) Waste Recycling : "ecycling differs from reuse in that the waste must first be treated before it can be used in a manufacturing process. )hen a transfer o f waste as is is not possible, reprocessing the waste for material recovery is known as recycling. -or e(ample, baghouse dust from scrap steel processors, containing upto !4 per cent zinc o(ide, can be combined with waste sulphuric acid to make galvaniser5s pickle acid. $he spent pickle liuor containing 617 per cent zinc sulphate and some iron salts is then usable, as fertiliser in agricultural fields. 2se of waste organic solvents is the best e(ample of recycling waste.
Treatment of Hazardous Wastes 'fter material recovery, the waste water containing hazardous waste chemicals should be deto(ified and neutralised through treatment. $here are many technologies available for treating hazardous wastes before they are ultimately disposed of. $heir aim is to modify the physical and8or chemical properties of the wastes so that they are rendered harmless. 0election of a treatment process depends on many factors such as the nature of the waste, the desired characteristics of the output stream, and economic and energy considerations. $he treatment technologies can be divided into the following groups, namely: •
physical treatment
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chemical treatment
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biological treatment
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solidification, and
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incineration
Physical treatment :
Is conducted using various methods such as phase separation. 3hase separation includes three steps, namely: lagooning, prolonged storage in tanks and sludge drying in beds. 9agooning and tank storage are collectively used to separate particulate impurities. Chemical treatment : Is used to facilitate complete breakdown of hazardous wastes and more usually to modify the chemical properties of the wastes, e.g., to reduce water solubility or to neutralise acidity or alkalinity. $he techniues involve o(idation, chemical reduction, neutralisation, heavy metal precipitation, oil8water separation and solvents8fuels recovery.
iological treatment : $he gross impurities obtained from treatment of sewage are collectively known as sludge, which is given biological treatment, before disposal. $his is known as sludge processing which has become important since improvements in industrial waste water treatment. $he typical technologies for sludge processing include conditioning, digestion, composting, thickening or dewatering and solidification. i/ Conditioning : In this step the sludge is e(posed to atmosphere for a stipulated period until a desired consistency is reached. ii/ !igestion : In this process the sludge is treated with bacteria which break down the long chain compounds into simpler ones iii/ Com"osting : In this step the organic matter in the waste sludge is converted into a usable stable material. Soldification : 3processes convert the liuid waste into insoluble, rockhard material and are used as pretreatment prior to landfill disposal. $his is usually done by mi(ing the waste with various reactants to produce a solid mass. $he basic aim of solidification process is to immobilise the hazardous constituents of the waste, so that these do not leach out at the landfill disposal site,
Collection# Trans"ort and !is"osal )aste disposal is a multiphase activity, the different stages of which, i.e. collection, interim storage, transport, treatment and disposal are highly interdependent, both technically and organizationally. 0afe collection and transport of hazardous waste form a critical link in the chain between its point of generation and its place of treatment and disposal. In many respects, the same precautions apply to hazardous waste in transit as apply to the carriage of dangerous goods however, additional problems arise from the hazardous nature of certain wastes because: i/ waste in general has no perceptible economic value to the generator ii/ the chemical and physical properties of a waste may not be precisely known because it is freuently a comple( mi(ture from which all economically useful components have been e(tracted :
iii/ mi(ing of noncompatible wastes for convenience in transit could create an acute hazard, either immediately or on treatment and disposal for e(ample, a mi(ture of ether waste containing a sodium residue with an aueous ether waste will e(plode/. $herefore, for a safe and secure disposal of hazardous waste, there should be a proper collection, transport and storage system. $he noncompatible wastes should be segregated and transported separately.
!ISP$S%& $' H%(%R!$S W%ST* $he final disposal of the hazardous wastes also needs to be carefully planned. $here are four different ways in which hazardous wastes can be finally disposed. 1.
9andfill disposal.
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Incineration.
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;umping at sea
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2nderground disposal
)e shall now discuss each of the above method of disposal of hazardous wastes. &andfill !is"osal $he disposal of hazardous waste by landfilling is an important method of disposal in many countries. 9andfilling means storing harmful substances under the ground. $his involves hauling the refuse to an area allocated for this purpose. In India such areas range from unsanitary o"en dum"s to properly operated sanitary landfills+ $"en dum"s are a poor method of waste disposal because they cause environmental problems. -or e(ample, they can ruin the appearance of all area and provide a home for rats and other rodents who spread disease. If garbage is e(posed, it rots and smells foul. Most dumps allow some burning, which fills the surroundings with smoke. In addition, rain water can drain through refuse and carry harmful substances to streams. 3roperly operated sanitary landfills cause little damage to the environment. $he area to be filled with waste must be lined with a nonporous substance such as clay, or high density polyethylene H+3
recent past, a new concept has developed in which the landfill site is constructed on a structure consisting of concrete cells. $he cell is a space for plant personnel to visit and observe any fault and repair the same. Incineration Incineration burns waste products. $his is another method many industries and large cities use if they do not have enough vacant areas for disposal sites nearby. Most hazardous wastes are deto(ified in this process. $his is also an e(cellent method of waste minimization, waste deto(ification and disposal, but its cost of operation is very high, if the heat content of waste is not reutilized. %d,antages Incineration is a 5process for the hightemperature o(idation of gaseous, liuid or solid wastes, convening them into gases and an incombustible residue. $he flue gases are released to the atmosphere with or without recovery of heat and with or without cleaning and any slag or ash produced is deposited in a landfill. In general, incineration may be considered as an alternative method of deto(ifying some nonrecoverable highly to(ic wastes. It is an e(cellent method of reducing waste volume, and in addition offers the possibility for recovering the heat content of the waste. In some communities heat from municipal waste incineration is used to produce steam. $his steam drives turbines that produce electric power. "ecycling of heat thus reduces the cost of operation of incinerators. Waste In"ut >enerally, the wastes having inflammable characteristics are incinerated. $he following types of wastes are commonly treated in hazardous waste incinerators: •
0olvent waste and sludges
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)aste mineral oils
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?arnish and paint wastes and sludges
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3lastics, rubber and late( waste sludges and emulsions
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+ils, emulsions and oil8water mi(tures
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3henolic wastes
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Mineral oil sludges
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"esin waste
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>rease and wa( wastes
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3esticide wastes
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'cid tar and spent clay
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+rganic wastes containing halogen, sulphur or phosphorus compounds.
)astes having high chlorine, sulphur, nitrogen and phosphorus contents, polychlorinated biphenyls 3&@/ and those containing heavy metals and carcinogenic substances need special incineration technologies and precautions. ' large number of municipal incinerators lack adeuate air pollution control devices. @urning in many of these devices may release gases and solid particles that may harm human health, damage property and kill plants. $he flue gases from ordinary incinerators can be dangerous in the absence of pollution control devices. -urthermore, as you have read earlier, incineration sometimes becomes a costly affair. !um"ing at Sea 'nother method of disposal of hazardous wastes involves dumping wastes at deep sea, designed to prevent contamination of groundwater. ;isposal at sea, of waste generated on land, is based on the misconceived notion thatthe enoromous volume of water available for dilution, enables the seas to be used as a dump without permanent damage. However, this is an erroneous conviction. $he decision to choose this method of disposal is generally based on financial considerations. $he site of disposal is determined by the geographical location of the waste producer. ;isposal of waste at sea is controlled by international legislation and by the national legislation reuired for the ratification of the international legislation. $o prevent pollution of the seas by the direct discharge of waste, the international legislation bans the dumping of e(traordinarily hazardous wastes such as organic silicon compounds, halogenated organics, mercury and its compounds, cadmium, carcinogenic waste and plastics into the sea. $he last of these can seriously disturb fishing and navigation.
nderground !is"osal It maybe e(cessively e(pensive to dispose off certain hazardous wastes, such as radioactive nuclear wastes, in an environmentally acceptable manner at landfill still sites or incinerate them at thermal treatment plants. $hese wastes are generated in all operations associated with the use of nuclear energy for national defence or peaceful purposes such as mining of radioactive ore, production of nuclear fuel, laboratory e(periments and medical treatment. 2nderground disposal may provide an .environmentally and economically viable option in case of radioactive wastes. $he underground disposal of hazardous waste is acceptable only in inactive or partially active mines that meet specific geological and technical criteria. )orldwide, only one deepmine disposal facility is c urrently in operation: a workedout halite8potash salt mine at Herfa Aeurode in the -ederal "epublic of >ermany now united >ermany/. 0alt mines are often used for radioacti,e -aste dis"osal because the e(cellent properties of salt deposits prevent the interaction of wastes with other geological formations. $he very e(istence of a salt deposit is a proof that the underground site has been unaffected by water for .millions of years. 0alt is impermeable to liuids and gases. ;ue to its hygroscopic nature, salt is capable of absorbing water entering ,the formation from outside and of repairing minor fractures by recrystallization, thus maintaining the original impermeability. $his feature is freuently supplemented by impermeable upper strata consisting of wastes, usually rock, from mines or other industries. $he atmosphere in salt mines is e(tremely dry, so metal euipment and containers do not rust. $here is no risk of methane e(plosions as in coal mines. @ursting of carbon dio(ide gas inclusions in the salt mines may be observed during e(cavation of rocks but this does not pose a risk, particularly after mining operations have ceased. $hermal conductivity of salt is good. 0alt is strong, permitting the
e(cavation of spacious, stable galleries. In addition, salt has a certain plasticity under pressure, allowing the dispersion of strain and increasing the overall stability. $hus, in principle you have learnt that there are four methods of waste disposal. 1.
9andfilling of solid wastes
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Incineration of inflammable organic wastes
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;umping of wastes at sea, and
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2nderground disposal usually of radioactive wastes.
