Thammasat Int. J. Sc. Tech., Vol. 9, No. 1, January-March 2004

The Evolution of Solid WasteManagement in Bangkok: Implications

for the FutureS. Muttamara and Shing Tet Leong

Environmental Engineering and Management Program, School of Environment,Resource and Development, Asian Institute of Technology, P.O. Box 4,

Khlong Luang, Pathum Thani 12120, Thailand.

Chairat Somboonjaroensri and Wicha WongpraditGarbagc Disposal Dision, Department of Public Clcansing, Bangkok

Metropolitan Administration, Bangkok, Thailand.

AbstractThe increasing quantity of solid wastes in Bangkok Metropolis causes serious problems in solid

waste management. Until recently, about 90% of the waste was carried directly from transfer stationswithout any treatment to landfill sites because there is no other available disposal facilities such assorting, compost plants and incinerators. The solid waste management problems can be categorized asfinancial, administrative, technical expertise and environmental awareness activities. Resourcerecovery and recycling was not performed efficiently, due to lack of enforcement system. However,the time has come when integrated technologies and maximum utilization should be considered as astrong disposal option against landfilling. Sustainable option such as mechanical-biologicalpretreatment (MBP) for landfilling and incineration could be employed in the future management ofsolid waste. The objective of this paper is to provide an overall view of the waste management inBangkok and to examine appropriate technical and economical viability that could be taken in wastemanagement.

Keywords: Bangkok, composting, incineration, landfill, recycling, solid waste management.

Introduction conceming collection, recycling, reduction andBangkok is the capital of Thailand with a reuse, transformation and final disposal. For

registered population of 8.4 million. It is facing example, about 90% of waste is carried directlyeconomic transition and experiencing rapid from transfer stations without any treatment tosocial changes. These problems present landfill sites because of no other disposaltremendous challenges to both policy makers facilities such as sorting, composting, andand the communities concerned. Bangkok as a incinerators. In addition, the general perceptionmega-city suffers notoriously for its inadequate of people about waste problems is still lackingsanitation, public services, pollution and awareness of the seriousness of this problem.congestion. Likewise, a rapid increase of wastes They make no effort to reduce waste.due to the trends of increasing population, massproduction and mass consumption and the The evolution of waste management inspread of a throw away lifestyle, causes serious Thailandproblems in solid waste management in Thailand's solid waste legislation has beenBangkok Metropolis. Consequently, attention based on the major revision of the followingshould be paid, in priority, to the waste situation laws in 1992 to achieve the followingand the existing waste management system. objectives:There is no proper solid waste management r Public Health Act-promotion of sanitationsystem to solve the municipal waste problem anddisposal ofsolidwaste

55

r Public Cleansing Act-the cleanliness andorderliness of the countryo Factory Act-avoidance of waste generationfrom factorieso Hazardous Substance Act-protect the publicfrom hazardous substances

The responsible agencies for municipalsolid waste within the Ministry the of NaturalResources and Environment are the PollutionControl Department (PCD) and the Departmentof Environmental Quality Promotion (DEQP).

These agencies are assigned duties under theregulations for environmental enhancement,project consideration, and consultancy. Allhazardous wastes are under the responsibilityand regulation of the Ministry of Industry (MOI)

and its agency, the Department of IndustrialWorks (DIW). The Department of Health(DOH), an agency under the MOPH, isresponsible for health care waste and infectiouswaste management. The Pollution ControlDepartment (PCD) is supposed to oversee wastewithin the Bangkok Metropolitan Region(BMR). The relationship between BangkokMetropolitan Administration (BMA) and thecentral government is that BMA is one of theorganizations under the Ministry of Interior.BMA has its own management, on which the isquite independent from the central government

[]. The BMA policy, direction and decision-making are agreed on within the BMA

Thammasat Int. J. Sc. Tech., Vol. 9, No. 1, January-March 2004

organization, and mostly do not have to beapproved by the central government except forsupporting budget requests.

Current status of solid waste

management in BangkokThere exists a great variation of daily per

capita waste generation in the BMR area, aproduction rate of 0.6-3 kglcapita/day isreported []. The Bangkok Metropolitan Regionis facing a serious waste disposal problem, withamounts of generated solid waste per dayoutstripping collection capacity by nearly 2,000uncollected tons of MSW per day. Bangkokcurrently generates 9,400 tons of solid waste perday. The BMA collection capacity is only 7,500tons per day. The challenge will increase with apredicted waste generation of around 16,000tons per day in 2015 (Figure l). Most previoussolid waste management studies do not considerthe waste generating factors, but focus solely onthe waste generation rates and the amount ofwaste at the transfer stations. However, Figure 2shows the present waste management system inBangkok Metropolis is greatly influenced byvarious factors such as the wastegeneration/discharge amount, social system,distribution system, etc. Thus, it is absolutelyessential to understand the current waste streamfor appropriate solid waste management of theBangkok Metropolis.

ts 1 6,000

ts 14 ,000

ts r 2,000

ts r o,oooE 8 ,00086,000ts4,ooots2,ooo

BOI 9 9 0 1 9 9 5 2 0 0 0 2 0 0 5

Y e a r

- - - ts -Co l lec ted r i las te

2 0 1 0 2 0 1 5

+ - S o l i d W a s t e Q u a n t i t r e s_ C - U n c o l l e c t e d W a s t e

Figure 1. Prediction of municipal solid waste generation and collection in the Bangkok

Metropolitan Region

56

Thammasat Int. J. Sc. Tech., Vol. 9, No. l, January-March 2004

Waste Generation

Recycle / Reuse

Figure 2. Present solid waste management system in Bangkok MetropolisSource: Department of Public Cleansing (BMA, 2001).

Sol id Waste

Management

t 5 %

Air Pol lut ion Control

2001Educat ion

9Vt

24.371 Million Baht

Figure 3. Expenditure classified by Bangkok Metropolitan Administration, Year 2001

Soc ia l Serv ice

8cn

Separate Discharge

Formal Recycling(Separation by BMA)

Recycling l( waste collectors

Transfer StationsRecycling 2(scavengers )

Final Disposal

57

B a n g k o k

S i n g a p o r e

M a n i l a

K u a l a L u m p u r

Jaka r t a

B r u n e i

Bangkok

Singapore

Man i l a

Kuala LumPur

Jakarta

Brunei

Thammasat Int. J. Sc. Tech., Vol. 9, No. 1, January-March 2004

0 . 8 |0 . 4 0 . 6

Genera t i on R a te ( kg /Pe rson /daY)

(a)

Per Capi ta Expendi ture in US$

(b)

Figure 4. Municipal solid waste management in Southeast Asian cities associated

wiitr (a) MSW generation rates and (b) per capita expenditure

Funding of municiPal solid wastemanagement

Local authorities that provide the collection

service also take care of the collection fees of

municipal solid waste' The current scale of

collection fee is limited to 40 Baht per capita per

month. The fees collected cover only 3-10%o of

the operational costs of waste management' In

addition, BMA can generate its own income and

revenues from local taxes, fee' fine, permits and

service charge, rental from BMA assets, and

income from public utilities and enterprises as

58

wgll as from miscellaneous activities.Operational costs of municipal solid wastedisposal often exceed 20Yo of municipal budgets(Figure 3). Compared with other cities in SouthAsian countries, major constraints ofmunicipalities of MSW management in BMRwere due to inadequate financing [2]. Figure 4a.shows that the MSW generation rate of BMRwas comparable to that of Singapore. However,the per capita expenditure associated with solidwaste management in BMR was much lower

Thammasat Int. J. Sc. Tech., Vol. 9, No. l, January-March 2004

than Singapore (Figure 4b). This could be due tothe differences between the two cities ineconomic level and living standard. Singaporecontributes higher financial expenditure towardwaste management. With limitations inoperational budget, the municipal solid wastemanagement in BMR has to rely on eithersubsidizes by the central govemment or foreigndonors who have financed many of the wastemanagement projects in Bangkok.

LegendLsf€r Sbh

bdlr 9s

o

o

N

f

l

{)

gr rrr /I

| '1 -zt' - l

Il

i rrsor xerorI

tI

---iIII(/ *o**o

1 r< r4ix^lMrcB^rEr -"-(

, I\,,1l i

/"( r

, rotttlluil \ ,

Locations of Solid Waste Transfer Stations and Landfill Sites in BanokokFigure 5

59

Refuse generation, collection and

disposal in BangkokIn Bangkok, the Department of Public

Cleansing accounts for 80% of the overallmunicipal cleansing services, which includescleansing and waste collection from streets,schools, markets, hospitals, commercial centers,etc. Curbside waste collection in Bangkok isdone from 6 pm to 3 am on the main streets andfrom 3 am to 10 am on the smaller lanes.Therefore, the delivery of waste to the transferstation may take place from 3 am to 1l am.Residents take their refuse out and place it incurbside bamboo baskets. Wastes are picked upby municipal waste collection crews andemptied into packer trucks. The capacity ofeachtruck is 5 tons. When fully loaded, the wastesare sent to one ofthe three transfer stations, On-Nooch (3500 tons/day), Nong-Khaem (3000

tons/day) and Tha-Rang (2000 tons/day) andsent directly to landfill sites in (Kampaeng Saen)Nakon Pathom and Rachataewa (Samut Prakan)which are the nearby provinces (Figure 5).About 20 tonnes per day of hospital hazardouswaste is incinerated at the On-Nooch disposalsite. Sorting of the raw waste is done by thewaste handling crew in parallel to the normalactivities of waste collection. The BMA has topay an average of 987.5 Baht per ton fortransportation fee. An average of 500 trips perday was made for each transfer stations. In

Thammasat Int. J. Sc. Tech., Vol. 9, No. l, January-March 2004

practice, this waste collection services 85-90%of the urban population in Bangkok Metropolis.The remaining uncollected waste is serviced byseveral private organizations. These smallcompanies account for approximately 20Yo ofcleansing services in Bangkok (Figure 6).

Options for solid waste management in

BangkokIn Bangkok, the conventional methods for

treating and disposing of most mixed solidwastes may be generally summarised as follows:Landfilling (options range from simple sanitarylandfill of untreated domestic refuse throughvarious transfer stations and bulk haulalternatives to remote landfill sites); Recycling(separation and processing of solid wastes atsource); Incineration (hospital waste treatment;this is without recovery of heat and residualslag); Composting (with varying degrees ofproduct refinement), Land filling is the mostcommon practice. The final choice of variousoptions available to the waste disposal authoritydepends on selecting the level of capital cost,pollution risk and environmental impact. Everyone of these alternatives requires land for itsresidues and, in general, operational costs andcapital investment are much higher for theincineration and composting systems.

lm00

8m0

600i)

?

4ff)0

20(x)

l00l 3

?

q

Figure 6. Collection of municipal solid waste in Bangkok, (1991-2001)Landfilling

60

LandfillingSince the composting and incineration

facil i t ies are not functioning effectively at allthe disposal sites, 97%o of the solid waste inBangkok is disposed of by landfil l ing. However,there is a capacity crisis at most of the landfillsites and this is becoming more serious becauseof the l imitation of land availabil ity due to therapid growth of population, economicdevelopment and uti l ization of the facil i t ies.Weak enforcement of land-use plans will makelandfil l ing facil i t ies to be unpleasant sites, sincethe community wil l enlarge closer to the site.NIMBY (Not in my backyard) syndrome makesit more difficult for the municipality to find anew landfill site. In addition, there are potentialrisks to health and environment from improperhandling of landfi l l sites. Water pollutionproblems experienced at landfi l l sites haveresulted from the percolation ofrain through thefill (called leachate) which affects the quality ofnearby surface water and may threaten thequality of the ground water [3]. Likewise, majorair pollution produced at landfi l l sites is due tothe gas generated in the process ofdecomposition. The gas contains COz and CHqprincipally and a small quantity of NH3, H2Sand CO. Apart from the toxicity of thesecomponents, the most serious problem at thelandfill site is the accumulation of flammablegas inside the landfil l layers which is diffused tothe land surface and on some occasions maycause fire or explosion.

CompostingA survey of MSW composition trends in

Bangkok revealed that the composition of solidwaste is largely organic garbage with vegetablecuttings and fruit peels which are suitable to thedispose of by composting, due to the highmoisture content (55% - 60%) and optimum C:Nratio. Figure 7 shows that about 53o/o ofBangkok municipal solid waste contains mostlyorganic matter or bio-waste. Bio-waste can beused for composting to produce naturalfertilizer. There are two approaches currentlyused in the composting of MSW. The firstapproach is the typical window system (pil ingon the ground), and the second approach uti l izesmechanical equipment to facil i tate thecomposting process, such as the rotating drumbeing used at BMA's Nong Khaem DisposalPlant. Composting on a large scale can be

Thammasat lnt. J. Sc. Tech., Vol. 9, No. l, January-March 2004

effective when the organic fraction is collectedseparately. This separation can be done athousehold level. The average cost of compostingis 530 Baht per ton of incoming waste [4]. Thereare some factors which favor composting as aresource recovery option. However, thecomposting activities only accounted for 3%o ofthe waste management. This is probably due tocross contamination of waste components andthe high level of glass, plastics and metalcontents in the waste stream, thus reducing theeconomic value of the compost products [5].Thus, marketing of the compost products hasbeen a problem in Thailand.

RecyclingRecycling is an attractive strategy to reserve

landfill space and reduce cost of transportingmaterials to landfi l l sites. Waste recyclingincludes any source reduction or wasteminimization activities undertaken by a wastegenerator that results in the reduction of totalvolume or quantity of waste t6] Wasterecycling minimizes the pollution effects causedby waste [7]. The informal sector's involvementin resource recovery from wastes had beenwidespread in Thailand during the economicboom period (1987-1996). In Bangkok,materials are separated at different stages ofthecollection proaess: at the source, prior tocollection; by the crews of the collectionvehicle; and by the scavengers at the disposalsite (Figure 8). The collected materials are soldthrough middleman to small-scale recyclingbusinesses, who sort and pretreat the materialsbefore selling them to a wholesaler, who in turndeals directly with the user industries. Materialssuch as newspapers, magazines, cardboard andbottles are separated at the source, often at theresidence itself and sold to door-to-doorcollectors on motor tricycles. Street scavengersalso sort out most valuable items from the wastebins and containers prior to collection by therefuse crews. These pickers generally sell thematerials to the junk shops, which also buylarger items directly from householders. Thesecond part of the recycling process is carriedout by the collection crews. These collectecmaterials are sold near the entrance of thedisposal sites. Ferrous metals are also recoveredby magnetic separator from the raw wasteentering the compost plants. The recoveredferrous metals are compressed into blocks of 30

6 l

kg weight. Recyclable items, once separated out,can be sold directly to recycling markets.Traders then sell them to domestic factories that

use them as raw materials. Table I shows quotedprices of some recyclable items. (Prices quoted

as of the beginning of the year 2000). The

amount of materials recovered by the scavengersvaries between 50- 150 kglperson/day and thedaily income varies between 30-300 BahVperson

[8]. Though recycling has been practiced for along time, it is still an informal practice and isnot widely developed, due to insufficienttechnical support, incentives, laws and

regulations, etc. The existing recycling systemin Bangkok is considered a self-sustainingsystem in the society or community and is muchmore efficient than that ofother countries [9].

Lohani (1982) reports that the success of

recycling programs requires interest and

cooperation from the population, along withpublic education for changing people's habits.It is important that all groups understand boththe environmental and economic implication ofrecycling, as well as the necessary practicalinstructions. that have to be followed in order to

Thammasat Int. J. Sc. Tech., Vol. 9, No. l, January-March 2004

ensure the high quality of the materials and anefficient collection of materials. If the materialsare collected at the source, the waste collectionworkers need information and training in howto handle recyclable materials to ensure thehigh quality materials are segregated and also toprotect themselves against pollution and otheroccupational health risks. Finally, the workersat the reclamation facilities should be clearlyinstructed in techniques for handling recyclablematerials.

Recyclable componentsFigure 7 shows the recyclable components

of municipal solid waste generated in Bangkok,during l99l-2000. Among the recyclablecomponents, plastic accounts for the biggestportion (19%), followed by paper, glass, andmetal, which contain about 9oh, 30/o, and 2%o,respectively, of total weight of recyclablecomponents. The "other" category comprisesorganic and non-organic matter such as treeleaves, residues of food and drink, stones, soil,etc.

199 '7 I 9 9 9 2 0 0 0r 9 9 8

Figure 7. Changes in composition of Bangkok municipal solid waste (1991-2000)

Source: Department of Public Cleansing, BMA.

| 992 1 9 9 3 1 9 9 4

62

Plastics: Recycled plastic is primarily usedin the manufacture of sleeping bags. pillows,protective wrap, grocery sacks, pipe and moldedproducts, etc.

Paper and Cardboard; Approximately 77%of recycled paper is mostly used to producecontainer board and construction products. Theremaining 23%o is used for other grades of paper,cellulose insulation and animal bedding.

Glass: The benefits of recycling glassinclude reuse of the material, energy savings,reduced use of landfill space, and in some cases,cleaner compost or an improved refuse-derivedfuel. Almost all recycled glass is used toproduce new glass containers and bottles. Aminor amount of glass is used to make glasswool or fiber glass insulation material.

Aluminum: Recycling has been sosuccessful for several reasons: a) recyclingprovides a stable, domestic source of aluminum

Broken bottleWhiskey bottleBeer bottleIronAluminiumCopperWriting paperNewspaperWaste paperCardboard

C o l l e c l i o n C r e w T r i c y c l i s t s

a . t H o u s e h o i d s 5 5 .

I a 1

J u n k S h o p s2 8 S .

Figure 8. Organisational methods in recycling process

Table I Selling Plige o{ Becyclable Items , __ . .. .Materials Selling Price (Baht/kg)

Thammasat Int. J. Sc. Tech., Vol. 9, No. l, January-March 2004

b) the energy required to produce a can fromrecycled aluminum is less than 5% of the energyneeded to make a can from raw materials c)about 93%o of the recycled cans can be remeltedand rolled into aluminum sheets [7]. Aluminumcans are accepted at curbside buy-backlocations, recycling collection centers, and byscrap metal dealers.

Ferrous Metals (Iron and Steel): Theprincipal recycled ferrous methls are tin cansand scrap metal through curbside collectionprograms.

Nonferrous Metals: Nonferrous metalscompose about 1 .50h of solid metal, includingtools, copper wire, pipe, automobiles, machinery

t7l.Other Wastes: These are comprised of yard

wastes, demolition wastes, wood, waste oil, usedtires, etc.

0.20- 0.300.70- 0.800.10- 0.201.50- 1.6014.70- 17.7039.70- 49.703.20- 3.301 .30 - 1 .800 .80 - 1 .101.20- 1.40

W a s t e t o L a n d f i l l

6 2 q .

Source: Department of Public Cleansing, (DPC,2000)*Exchange rate at the beginning ofthe year: 42 Baht = 1 US$

63

Environmental awareness activitiesInstitutional planning is the key to achieving

an acceptable and affordable system, but thesuccess of any scheme will depend on the

cooperation of the people and their aspirationsfor a safe and aesthetically pleasing urbanenvironment. To cope effectively with wasteproblems, it is suggested that along with othermeasures, the education of people on wasteawareness and creation of proper, responsiblebehavior regarding waste and environment mustbe the long-term strategic approach.

Based on a UNEP 1991 report [10], theexperiences gained from activities inenvironmental education and the institutionalset-up developed for this purpose over the years

will be useful in the promotion of environmentalawareness. The enhancement of environmentalawareness among the target population may be

achieved through formal and non-formaleducation as well as mass media.Manufacturers and distributors are obliged toaccept returned packaging. Plastic packaging is

collected by industry and recycled in anenvironmentally sound way. Negotiationsbetween the government and producers,

suppliers and users are carried out to promote

recycling. To enhance recycling and reuse,products are designed in such a way that

components and materials can be easilycollected and separated after the product is

discarded. Such changes lie with product

manufacturers. Any environmental program

will fail without the people's support on local,

regional and national levels. An increasing

awareness of the need for an active

environmental protection policy is dependenton our collective actions.

Lack of enforcement systemAlthough the regulation of Bangkok

Municipality can be legally enforced on

violators, in practice it is very weak because ofa

poor enforcement system. The separate

collection system for the segregation of kitchen

waste, recyclable waste, hazardous waste, andgeneral waste was introduced to some areas in

Bangkok Metropolis by BMA a few years ago'However, the system is not fully entrenched dueto the weak enforcement.

There was a survey carried out by BMA that

shows thirty percent of residents in the city are

cooperating in the implementation of separate

Thammasat Int. J. Sc. Tech., Vol.9, No. 1, January-March 2004

collection. The public opinion survey shows that32 percent of the respondents use plastic bagsfor waste discharge, while 51.6 percent usemetal containers [].

Future perspectivesAs it can be seen, the Present waste

management policy of "Each communityoperates its own disposal facilities" is regardedas impractical. The biggest constraint is lack ofbudget for the overall operation, despite thegrowing awareness of the seriousness of ever-increasing waste generation and waste relatecproblems. In future municipal solid wastemanagement, the central government has tosupport local administration to set plans forcentralized disposal centers and to improvesound waste management systems within the

environmental regulations. Based on theprediction of waste generation and changes in

composition of municipal solid waste, the future

solid waste disposal approaches are forecastedto employ both integrated technologies (70%)

and maximum util ization (30%);'namely:

e Waste segregation for recyclingIn future waste management practice, the BMA

has launched a public awareness campaign toencourage the separation of wet and dry MSW'BMA's policy has created a recycling centre to

sort paper, plastic, glass and metal in eachmunicipal district. For downstream sorting,plastic bags are provided to customers by

supermarkets, department stores, etc. and aremarked according to the type of waste that it

should be used for:a. Yellow bins: for recyclable waste, i.e.plastics, glass and metals;b. Green bins: for kitchen waste, i.e. freshorganic garbage;c. Grey bins with a red lid: for hazardous waste,

i.e. bulbs and batteries;d. Blue bins: for ordinary mixed garbage and

trash.

r Composting for organic solid wasteComposting on a large scale could be more

effective by separating more efficiently beforecollection. Composting on a small scale can alsobe effective when the organic fraction is

collected separately at household level.

64

o Optional mechanical - biological pretreatment(MBP) for landfilling and incineration

Several research programs have alreadyproven that waste pretreatment before disposalis very effective to reduce the environmentalimpact of landfi l l ing tl l l Compared tountreated waste, mechanical-biologicalpretreatment (MBP) provides a reduction inorganic content of end products and contributeto the reduction ofthe global greenhouse effectBiodegradable fractions with high organiccontent are destined for biological treatmentbefore landfil l ing. The mechanical-biologicalpretreated waste mass is reduced by 20-40%o anddensity after compaction is expected to increasefrom about 0.8-0.9 t/m3. to 1.2-1 .4 Um3. with alandfill volume reduction up to 60% incomparison to non pretreated waste [12; l3].Emission qualities are also significantlyimproved, with a reduction of about 90oh ofCOD and total nitrogen in leachate, as well asgas production rate reduction. Likewise,mechanical - biological pretreatment (MBP) andincineration techniques are currently adopted assingle waste treatment technologies in somedeveloped countries [4]. MBP can be used as apretreatment step before thermal treatment, withan improvement of the heating value and areduction of the amount of non-combustiblewaste to be incinerated.

r Participation from private sectorIncreasingly, the private sector and

voluntary organizations are playing a part instreet cleansing and solid waste management. Asuitable plan must achieve desirable objectives,taking advantage of all available resources. Inaddition, appointing private sector companies tocollect and dispose of waste can generaterevenues for local governments.

ConclusionThe exploratory nature of this research

shows that an integrated waste disposal planwould be the better choice for MSWmanagement in Bangkok. However, it is notpossible to decide which option is best. This ispartly due to the fact that this study did notcover some other important issues such as;public demonstrations against incinerators,market demand for composting products, thelegislative support for landfilling, etc. Forexample, the physical impacts from landfill site

Thammasat Int. J. Sc. Tech., Vol. 9, No. I, January-March 2004

can create NIMBY (Not in my backyard)syndrome,* making it more difficult for publicacceptance. To assist policy makers inidentifying viable options for solid wastemanagement, the Life Cycle Assessment (LCA)method is recommended to quantiry theenvironmental and social impacts withoutconsideration of costs of investment.

References

[1] Bangkok Metropolitan Administration,(BMA 2000). Statistical Profile ofBangkok Metropolis. Department ofPolicy and Planning, BangkokMetropolitan Administration, Thailand.

[2] World Bank (1999)., What A Waste : SolidWaste Management in Asia, Urban andLocal Working Paper Series No. 1, May1999.

[3] Pohland, F.G. and Harper, S.R., CriticalReview and Summary of Leachate and GasProduction from Landfills. Report No.EPA/600/2-861073, U.S. EnvironmentalProtection Agency, December 1985.

[4] Iapan International Cooperation Agency(JICA, 1999) Report to BangkokMetropolitan Administration, The Study forthe Master Plan on Sewage SludgeTreatment and Disposal and WastewaterReuse in Bangkok", October 1999.

[5] Lohani, B.N., Recycling Potentials of SolidWaste in Asia Through Scavenging.Conservation and Recycling, Vol. 7, No. 2-4 , pp . 181 -190 , 1984 .

[6] USEPA, Waste Minimization OpportunityAssessment Manual. Hazardous WasteEngineering Research Laboratory. UnitedStates Environmental Protection Agency,Cincinnati, Ohio, I 988.

[7] Tchobanoglous, G., Theissen, H. and Vigil,S. A., Integrated Solid Waste Management:Engineering Principles and ManagementIssues. New York: McGraw-HillInternational Editions, I 993.

[8] Department of Public Cleansing (DPC2000). Fact Finding and Information forSolid Waste Management in Bangkok,Department of Public Cleansing, BangkokMetropolitan Administration, Thailand.

[9] Puncharoen, N., Strategy of Refuse, WasteDisposal and Resource Recovery.Proceeding of the 2no Regional Seminar on

65

Solid Waste Management, BangkokThailand, 1993.

[0] LrNEP-UNIDO, Audit and ReductionManual of Industrial Emission and Wastes.Technical Report Series No. 7, Paris:United Nations Environment Program andUnited Nations Industrial DevelopmentOrganization, 1991.

[1]Burnley S.J., Coleman T., Gronow J.R.,The Impact of the Landfill Directive onMunicipal Waste Management. Sardinia 99,Proceedings of the Seventh InternationalLandfill Symposium, 04-08 October 1999,S. Margherita di Pula, ltaly,1999.

[2] Leikam K. and Stegmann R., Mechanical-Biological Pretreatment of ResidualMunicipal Solid Waste and the LandfillBehaviour of Pretreated Waste.Sardinia 97.

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Proceedings of the Sixth InternationalLandfil l Symposium, l3-17 October, S.Margherita di Pula, Italy, Volume I, pp.463-474, t997.

[13] Scheelaase T. and Bidlingmayer W., Effectof Mechanical-Biological Pretreatment onResidual Waste and Landfilling Sardinia97, Proceedings of the Sixth InternationalLandfill Symposium, 13- l7 October, S.Margherita di Pula, Italy, Volume I, pp.475-484,1997.

[14] Soyez K., Thran D., Volker D. and KollerM., The German Federal ResearchProgramme on Mechanical-BiologicalPretreatment. Sardinia 97, Proceedings ofthe Sixth International LandfillSymposium, 13-17 October, S. Margheritadi Pula, Italy, Volume l, pp. 439-448, 1991.

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