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Decision Makers’ Guide to

Municipal Solid Waste

Incineration

The World BankWashington, D.C.

© 1999 The International Bank for Reconstructionand Development / THE WORLD BANK

1818 H Street, N.W.Washington, D.C. 20433, U.S.A.

All rights reservedManufactured in the United States of AmericaFirst printing August 1999

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Library of Congress Cataloging-in-Publication Data

PLEASE PROVIDE

iii

Foreword v

Solid Waste Incineration 1

Institutional Framework 2

Waste as Fuel 5

Economics and Finance 7

Project Cycle 10

Incineration Technology 11

Contents

v

Foreword

The Decision Makers’ Guide to Incineration of MunicipalSolid Waste is a tool for preliminary assessment of thefeasibility of introducing large-scale incinerationplants into the waste management systems of majorcities in developing countries.

The Decision Makers’ Guide targets waste manage-ment authorities, as well as institutions involved infinancing public utility projects. This guide identifiesthe most important factors in assessing short- and long-term viability of municipal solid waste incineration.

Fulfillment of the key criteria of the Guide (manda-tory, strongly advisable, or preferable) does not neces-sarily mean that a project is feasible. Compliance withthe key criteria simply allows the project proposer toproceed with a proper feasibility study with limitedrisks of a negative outcome.

Noncompliance with one or more of the mandato-ry key criteria, however, indicates a significant risk that

the project is not institutionally, economically, techni-cally, or environmentally feasible. Therefore, either theproject should be redesigned, or the unfulfilled criteriashould be studied in depth to clarify their influence onthe project viability.

The supporting Technical Guidance Report providesthe foundation for a much more detailed evaluation ofall the aspects of a proposed project. The Report is spe-cific and requires some prior technical knowledge(although not necessarily about waste incineration). Itis thus intended mainly for the organizations support-ing the decision-makers.

The Guide was prepared by Mr. J. Haukohl, Mr. T.Rand, and Mr. U. Marxen of RAMBØLL, and it wasmanaged by Mr. J. Fritz of the World Bank. It wasreviewed by Dr. C. Bartone of the World Bank and byMr. L.M. Johannessen, long-term consultant to theBank.

Legend

MSW: Municipal solid waste (domestic and similar)ISW: Industrial solid wasteMass burning: Incineration of MSW as receivedIncineration plant: Treatment facility for solid waste with energy recovery and emission control

Key criteria identifying the factors influencing the decision-making process are listed in order of priority, usingthe following grading system:

✓ ✓ ✓ Mandatory key criteria✓ ✓ Strongly advisable key criteria✓ Preferable key criteria

If a mandatory key criterion cannot be expected to be fulfilled, further planning of a solid waste incineration plantshould be stopped.

Note: Decision flow charts in the text can be applied to clarify whether a key criterion may be considered fulfilled.

Solid Waste Incineration

Municipal solid waste (MSW) incineration plants tendto be among the most expensive solid waste manage-ment options, and they require highly skilled person-nel and careful maintenance. For these reasons, incin-eration tends to be a good choice only when other,simpler, and less expensive choices are not available.

Because MSW plants are capital-intensive andrequire high maintenance costs and comparativelyhigher technically trained operators, they are common-ly adopted by developed countries. However, high cap-ital and maintenance costs may make MSW incinera-tion beyond the reach of many of the lesser developingcountries. The Decision Makers’ Guide aims to reducesuch mistakes by clarifying some of the basic require-ments for a successful incineration plant project.

Incineration AdvantagesIncineration is an efficient way to reduce the waste vol-ume and demand for landfill space. Incineration plantscan be located close to the center of gravity of waste gen-eration, thus reducing the cost of waste transportation.Using the ash from MSW incinerators for environmen-tally appropriate construction not only provides a lowcost aggregate but further reduces the need for landfillcapacity. In particular, incineration of waste containingheavy metals and so on should be avoided to maintaina suitable slag quality. (However, ordinary householdwaste does contain small amounts of heavy metalswhich do not readily leach under field conditions andwhich routinely pass USEPA TCLP tests.) The slag qual-ity should be verified before it is used. Energy can berecovered for heat or power consumption.

All waste disposal alternatives eventually decomposeorganic materials into simpler carbon molecules such

as CO2 (carbon dioxide) and CH4 (methane). The bal-ance between these two gases and time frame for thereactions varies by alternative. Incineration providesthe best way to eliminate methane gas emissions fromwaste management processes. Furthermore, energyfrom waste projects provides a substitute for fossil fuelcombustion. These are two ways incineration helpsreduce greenhouse gas emissions.

One of the most attractive features of the incinera-tion process is that it can be used to reduce the origi-nal volume of combustibles by 80 to 95 percent. Airpollution control remains a major problem in theimplementation of incineration of solid waste dispos-al. In the United States, the cost of best available tech-nology for the incineration facility may be as high as35 percent of the project cost. The cost of controlequipment will, however, depend upon the air pollu-tion regulations existing in a given lesser developingcountry.

Waste incineration may be advantageous when alandfill cannot be sited because of a lack of suitable sitesor long haulage distances, which result in high costs.

Incineration DisadvantagesAn incineration plant involves heavy investments andhigh operating costs and requires both local and for-eign currency throughout its operation. The resultingincrease in waste treatment costs will motivate thewaste generators to seek alternatives. Furthermore,waste incineration is only applicable if certain require-ments are met. The composition of waste in develop-ing countries is often questionable in terms of its suit-ability for autocombustion. The complexity of anincineration plant requires skilled staff. Plus, theresidues from the flue gas cleaning can contaminate theenvironment if not handled appropriately, and must be

1

Decision Makers’ Guide to Municipal Solid Waste Incineration

disposed of in controlled and well-operated landfills toprevent ground and surface water pollution.

Applicability of IncinerationMSW incineration projects are immediately applicableonly if the following overall criteria are fulfilled.

• A mature and well-functioning waste managementsystem has been in place for a number of years.

• Solid waste is disposed of at controlled and well-operated landfills.

• The supply of combustible waste will be stable andamount to at least 50,000 metric tons/year.

• The lower calorific value must on average be at least7 MJ/kg, and must never fall below 6 MJ/kg in anyseason.

• The community is willing to absorb the increasedtreatment cost through management charges, tip-ping fees, and tax-based subsidies.

• Skilled staff can be recruited and maintained.• The planning environment of the community is sta-

ble enough to allow a planning horizon of 15 yearsor more.

Institutional Framework

The success or failure of an incineration schemedepends on the attitude of the multiple stakeholdersand on the legislative and institutional framework cur-rently in place.

Stakeholders in an MSW incineration plant projectoften have conflicting interests. The project thereforecan become an environmental and economic issuewith many groups.

The stakeholders’ reaction to the project may differdepending on the institutional setting of the plant. Theincineration plant can be located in the waste sector(preferable) or the energy sector, or it can be a fully pri-vatized independent entity. In any case, the incinera-tion plant must be an integral part of the waste man-agement system.

Depending on the organizational affiliation of theplant, there is a need for strong irrevocable agreementsregulating the supply of waste, the sale of energy, andthe price setting.

A high degree of interaction, either through owner-ship or long-term agreements, between the differentparts of the waste management system and the wasteincineration plant is important to avoid environmen-tal, institutional, or financial imbalances in the overallsolid waste management system.

The Waste SectorA well-developed and controlled waste managementsystem is considered a prerequisite to an MSW incin-eration plant. Generators consider waste to be a nui-sance and want to dispose of it at the lowest possiblecost. However, many people who work formally orinformally with waste collection, transportation, recy-cling, and disposal seek to maximize their profit ormake a living.

Existing regulations and enforcement must there-fore be highly efficient to ensure that all waste whichcannot be recycled is disposed of at controlled andwell-operated landfills. This goes for both municipalsolid waste, often taken care of by a public waste man-agement system, and industrial solid waste (ISW), gen-erally handled by independent waste companies.

Overall control of the waste flow—including ISW, ifpart of the design volume—is important to ensure reli-able supply of suitable waste to the waste incinerationplant.

Mature solid waste management systems are highlyintegrated and operated efficiently under public finan-cial and budgetary control. They include organizations

2 Municipal Solid Waste Incineration

Energy Sector

Power producersPower distribution companyIndustries selling heat/powerDistrict heating companyPower/energy consumers

Community

Environmental NGOs Nature/Wildlife NGOs Community groupsNeighbouring citizensScavengers

Waste Incineration Plant

Waste Sector

Waste generatorsWaste recycling companies

Waste collection companiesOther treatment plants

Landfill operators

Authorities

Local/provincial government Urban/regional planningEnvironment authoritiesHealth authoritiesTraffic authorities

Figure 1 Relevant stakeholders

involved in the collection, transportation, and dispos-al of waste in environmentally controlled landfills.Costs for some systems are fully paid by the generators(although some are tax-supported or subsidized).Introducing new facilities into such a system calls foroptimizing and controlling the waste flow and feestructure to maintain a balance between the differentdisposal options. In order of complexity, energy can berecovered as hot water, low grade steam, super heatedsteam for electricity generation, or a combination ofthe steam options.

Public awareness campaigns emphasizing waste min-imization, recycling, and proper waste management arealso part of a mature waste management system.

The Energy SectorIncineration of MSW is significantly more expensivethan controlled landfilling. For a plant to be economi-cally feasible, costs must be minimized through sale ofenergy recovered.

The primary concern is the end use of the energyproduced: district heating, steam, electricity, or anycombination. Therefore, the characteristics of the ener-

gy sector play an important role when considering anMSW incineration plant.

Sale of energy in the form of hot water for districtheating purposes—or in particular cases, low pressuresteam to large-scale industrial consumers nearby, pro-vided that sufficient contracts and guarantees can bearranged—minimizes plant construction costs andrecovers a high percentage of energy. Sale of combinedpower and heat or steam results in a degree of energyrecovery that is no higher, but the cost and the com-plexity of the plant are increased.

The energy sector is often heavily regulated.Concession to produce and sell electricity is generallygranted to a limited number of public and privateoperators. An incineration plant established by anoth-er authority or a private organization may thereforeencounter difficulties before gaining the necessaryapprovals and agreements. Early co-operation with theend user organizations is therefore useful.

It is most feasible when the energy can be sold to oneconsumer for its own use or resale. The consumer maybe a utility company with an existing distribution net-work, for example.

Energy prices are often subject to taxation or arepartly subsidized. Pricing may therefore be a politicalissue requiring a government decision. Also, in mostdeveloped countries, energy prices are controlled byfiscal measures to favor energy production based onbiomass fuels.

Political and socio-economic considerations play animportant role when fixing the price of waste-generatedenergy. A high price resulting in a reduction of the wastetipping fee favors the waste sector, and low energy pricesfavor the energy consumers.

Community AspectsThe community and NGOs where a new MSW inciner-ation plant is to be established are often concerned aboutenvironmental impacts. These concerns may arise froma lack of knowledge, general resistance towards changes,or fear of the unknown, such as higher waste manage-ment charges, loss of subsistence, or fear of pollution.

Public awareness campaigns initiated in the earlyplanning stages can alleviate this concern.Furthermore, a detailed discussion about the environ-mental protection measures included in the project—

Decision Makers’ Guide 3

Optimumscenario

Improvementrequired

Acceptablescenario

No

Yes

No

Yes

Yes

No

Yes

Is the wastecollection systemwell-organized withclear division ofresponsibilities andcontrol of all wastetypes?

Investigate the feasibilityof the waste as fuel

Is wastedisposed of inenvironmentallycontrolledlandfills?

No

Yes

No

Yes

No

Yes

No

Yes

No

Con-trol of alltypes ofwaste

Is waste disposalfully controlled?

Allwaste

MSWonly

Allwaste

MSWonly

Upgradecollection

system beforeintroducingincineration

Upgradedisposal

system beforeintroducingincineration

Revise wastecharge system

beforeincineration

Implementcontrolled

landfills beforeincineration

Do the wastegenerators pay forthe full cost ofwaste collection and disposal?

MSW& ISW

House-holds

Onlymunicipal

solidwaste

Figure 2 Assessment of Waste Management System

not only with the environmental authorities, but alsowith the organized NGOs—is necessary.

In the design phase, the environmental authoritiesare to establish standards for the plant emissions andhandling of the residues. In the operational phase, thesame authorities will need to control and enforce thosestandards.

The public concern may lessen if the environmentalauthorities and those in charge of the MSW incinera-tion plant are truly independent of one another.

Plant Ownership and OperationThe number of stakeholders around an MSW inciner-ation plant will result in diverging and conflictinginterests. Depending on who owns the incinerationplant, institutional borderline problems may ariseregarding delivery of a sufficient quantity and qualityof waste, the pattern and price of sale of energy or both.Problems must be solved at an early stage throughdetailed long-term agreements. Key agreements arethose related to waste supply and energy sale.

Municipally operated incineration plants have manybenefits. The municipality can control the collectionand transport of waste to the facility (although this isnot always the case). The public has some confidence

that the municipality will ensure the environmentalperformance of the facility. In many cases the publicenergy distribution organization finds it easier to nego-tiate with another public body, which minimizes thepotential for problems.

There must be a mechanism to ensure the long-termviability of the incineration facility. The risks involvedin financing such operations relate to controlling costsand revenues. Waste tipping fees and energy sales pro-vide revenues. Contracts that guarantee waste volumesand price over the life of the project are important, andmust address the potential for short falls in wastereceipts. Energy generation potential relates to both thequantity and quality of the waste received. The deteri-oration in waste quality can lead to decreased energyproduction—in which case, energy sales revenues willalso decrease. The facility must have guarantees thatallow operations to be sustained. The communitywhere the facility is established will thus have to acceptthe economic risk.

Operation and maintenance of the plant requiresskilled managers, operators, and maintenance staff, sostaff recruiting and developing are important. Theskills required are similar to those of the energy sector.The owner may choose to subcontract all or part of theoperation and maintenance of the facility to privatecompanies with long-standing practical experience.

Worldwide, there are few experienced manufactur-ers and builders of MSW incineration plants. Hence,foreign currency will be needed not only for the initialinvestment but also for certain spare parts. The plantmust therefore be organized with unhindered access toprocurement of spares and services paid for in bothlocal and foreign currency.

Key Criteria for Institutional Framework

✓ ✓ ✓ A solid waste management system, com-prising a controlled and well-operatedlandfill, has been functioning well for anumber of years.

✓ ✓ ✓ Solid waste collection and transportation(MSW and ISW) are managed by a limitednumber of well-regulated/controlled organ-ization(s).


Select hotwater or LPsteam boiler

for costefficiency.

Selectsteam boiler,turbine with

outlets for steamand hot water

circuit.

Select asteam boilerwith turbineand cooling

circuit.

Is only sale of electricpower possible?

May the energybe sold as acombination ofelectricity and heator steam?

Is the MSW incinerationplant locatedwhere all energyrecovered can be soldfor district heating orsteam for industrialpurposes?

Re-assess the economicfeasibility of the project.

Yes

No

Yes

No

Yes

No

Energy recoveredcannot be brought to

good use!!

Figure 3 Assessment of Potential Sale of Energy

✓ ✓ ✓ There are signed and approved letters ofintent or agreements for waste supply andenergy sale.

✓ ✓ ✓ Consumers and public authorities are ableand willing to pay for the increased cost ofwaste incineration.

✓ ✓ ✓ Authorities are responsible for controlling,monitoring, and enforcing operations.

✓ ✓ ✓ A public guarantee is available for repay-ment of capital costs and operation costs

✓ ✓ The authorities responsible for control,monitoring, and enforcement are indepen-dent of the ownership and operation of theplant.

✓ ✓ Skilled staff for plant operation are availableto the plant owner at affordable salaries.Otherwise, there must be long-term reliableoperation and service contracts.

✓ The waste management authority owns theincineration plant.

Waste as Fuel

A most crucial factor in the feasibility of an MSWincineration plant is the nature of the waste and itscalorific value. If the mandatory criteria for waste com-

bustibility are not fulfilled, the project should be ter-minated.

As a result of the socio-economic situation in manylow to middle income countries or areas, only limitedamounts of useful resources are wasted. Organized andinformal recycling activities in the waste handling sys-tem tend to reduce the amount of paper, cardboard,and certain types of plastic in the waste. Additionally,the waste may have high ash and moisture content.

Municipal solid waste in such areas therefore oftenends up with a low calorific value and its ability to burnwithout auxiliary fuel is questionable either year-round or in certain seasons. In areas with heavy pre-cipitation, closed containers for collection and trans-portation should be used to avoid a significant increaseof the water content of the waste.

Industrial, commercial, and institutional wastes(except from market waste) tend to have a significant-ly higher calorific value than domestic waste. Mixingdifferent types of wastes may therefore make incinera-tion possible. However, the collection system must bemanaged well to maintain segregated collection underthese circumstances.

Waste generation depends highly on socio-econom-ic conditions and the degree of urbanization andindustrialization. In general, waste generation andcomposition data cannot be projected from one placeto another. Introduction of advanced waste treatmentfacilities must therefore always be based on a compre-hensive local waste survey.

Introduction of advanced waste treatment likeMSW incineration will have a significant impact onexisting informal recycling activities. For example,


Table 1:Waste generation

Waste Generation(kg/cap./year) Annual

Area Range Mean growth rate

OECD–total 263–864 513.0 1.9%North America n.a 826.0 2.0%Japan n.a. 394.0 1.1%OECD–Europe n.a. 336.0 1.5%

Europe (32 countries) 150–624 345.0 n.a.8 Asian Capitals 185–1,000 n.a. n.a.South and West Asia (cities) 185–290 n.a. n.a.Latin America and the Caribbean 110–365 n.a. n.a.

n.a. = Not applicable.Source: cf. Technical Guidance Report

scavengers may lose their source of income. Even ifthese people are compensated for their loss of income,some of them will shift to the early stages of the han-dling system. This may alter the composition and com-bustibility of waste arriving at an incineration plant.Scavenging and other recycling activities must there-fore be carefully managed.

The waste survey must account for the existing wastecomposition and calorific value and for expectedchanges during the adopted planning period. Annualvariations must be carefully surveyed and assessed, forexample, by conducting a year-long sampling programto establish waste constituents, trends,and seasonal vari-ation, as well as variation between collection areas. Theaverage annual lower calorific value must be at least 7MJ/kg, and must never fall below 6 MJ/kg in any season.

Key Criteria for Waste as Fuel

✓ ✓ ✓ The average annual lower calorific valuemust be at least 7 MJ/kg, and must never fallbelow 6 MJ/kg in any season.

✓ ✓ Forecasts of waste generation and composi-tion are established on the basis of wastesurveys in the catchment area of theplanned incineration plant. This task mustbe carried out by an experienced (and inde-pendent) institution.

✓ ✓ Assumptions regarding the delivery of com-bustible industrial and commercial waste toan incineration plant should be founded onan assessment of positive and negativeincentives for the various stakeholders todispose of their waste at the incinerationfacility.


Table 2: Waste components

% of waste Guangzhou, China, 8 districts Manila 22 European countries1993 1997 1990

Fraction Range Mean Mean Range Mean

Food and organic waste 40.1–71.2 46.9 45.0 7.2–51.9 32.4Plastics 0.9–9.5 4.9 23.1 2–15 7.5Textiles 0.9–3.0 2.1 3.5 n.a. n.a.Paper and cardboard 1.0–4.7 3.1 12.0 8.6–44 25.2Leather and rubber n.a. n.a. 1.4 n.a. n.a.Wood n.a. n.a. 8.0 n.a. n.a.Metals 0.2–1.7 0.7 4.1 2–8 4.7Glass 0.8–3.4 2.2 1.3 2.3–12 6.2Inerts (slag, ash, soil,

and so on) 14.0–59.2 40.2 0.8 n.a. n.a.Others n.a. n.a. 0.7 6.6–63.4 24.0

n.a. = Not applicable.Source: cf. Technical Guidance Report

No

Yes

No

Yes

No

Yes

No

Yes

Has a survey beenconducted to establish theamount of MSWgenerated in the area?

Do records document theannual variation in wastevolume and composition?

Is the lower calorific valueof the wastedocumented to be at least6 MJ/kg throughout allseasons? (Average annualLCV>7 MJ/kg)

Has the effect ofscavenging and recyclingon the waste volume andcomposition beeninvestigated?

Conduct awaste

monitoringprogram

Conduct awaste

monitoringprogram

The waste isnot suited forincineration

Evaluate theconsequencesof introducingincineration

The waste is likelyfeasible for mass

burning

Figure 4 Assessment of Waste as Fuel

✓ ✓ The annual amount of waste for incinera-tion should not be less than 50,000 tons, andthe weekly variations in the waste supply tothe waste incineration plant should notexceed 20 percent.

A preliminary feasibility assessment of using a par-ticular waste as fuel can be made on the basis of thecontent of ash, combustible matter (ignition loss of drysample), and moisture.

The maximum amount of energy recoverablethrough MSW incineration depends primarily on thelower calorific value of the waste, but also on the sys-tem applied for energy recovery. It is most efficientwhen both electricity and steam/heat are produced,and the yield is lowest when only electricity is generat-ed and the surplus heat is cooled away.

Energy prices vary greatly from place to place, evenwithin the same country. Electricity is a high-valueenergy form, so a low energy yield is, to some extent,compensated for through price differences.

Economics and Finance

MSW incineration is an advanced waste treatmenttechnology which is costly to implement, operate, andmaintain. A significant amount of foreign currencymust be available for the initial procurement of equip-ment and spares, and for replenishing stocks of sparesand for expatriate expert plant overhauls later.

Normally, MSW incineration furnaces are designedwith a capacity limit of about 20 to 30 metric tons/h.The recommendation is 10 to 20 metric tons/h. It is rec-ommended to divide the total plant capacity into twoor more identical incineration lines, thus improvingthe plant’s flexibility and availability—for example,when one line is closed for maintenance.

The investments in an MSW plant depend to agreat extent on the required form of energy output.The least expensive plants are those equipped withhot water boilers only. Production of steam and elec-tricity makes the investments in mechanical plant andcivil works much higher (about 40 percent). The


Table 3: Fuel characteristics of MSW

Guangzhou, China Manila,8 districts, 1993 5 districts, 1994 Philippines, 1997

Parameter Units Range Mean Mean Mean

Combustible % 14.6–25.5 22.3 31.4 37.6Ash % 13.8–43.1 28.8 22.0 15.6Moisture % 39.2–63.5 48.9 46.6 46.7

Lower calorific value kJ/kg 2,555–3,662 3,359 5,750 6,800

6 70.00

0.50

1.00

1.50

2.00

2.50

3.00

8 9 10 11

Figure 5 Energy Recovery

MW

h/m

etri

c to

n

Lower Calorific Value (MJ/kg)

CHP Power only Heat only

0.0

10.0

20.0

30.0

40.0

50.0

60.0

6 7 8 9 10 11

Figure 6 Value of Energy Sale (Based on an electricity price of $35/MWhand a heat price of $15/MWh)

US$

/ton

Lower Calorific Value (MJ/kg)

Heat and power Heat Power

operating costs are also higher for electricity produc-ing facilities.

Figures 7 and 8 indicate estimated investments andnet operating costs as of mid 1998 as a function of theannual amount of waste processed at power generatingplants. It is, furthermore, assumed that the plants areequipped to meet medium level emission standards(see next section). Compliance with basic emissioncontrol allows only a 10 percent investment reduction.The assumed operating time is 7,500 hours annually.The curves are valid only for plants designed for wastewith a lower calorific value of less than 9.0 MJ/kg.Furthermore, the electricity sale price is assumed to be$35/MWh.

The figures indicate a significant scale of economywith respect to investment as well as net treatmentcosts.

The net treatment costs of an MSW incinerationplant are rather sensitive to fluctuations in the quanti-ty and quality of waste treated. The net costs sensitivi-

ty graph indicates the resulting change in treatmentcosts if the waste has a reduced calorific value or if thesupply of waste falls short of the design load.


0

0 500 1,000 1,500 2,000 2,500

100 200 300 400 500 600 700 800

Figure 7 Estimated Cost of Incineration Plants

0

50

100

150

200

250

300

350

0

30

1,00

0 U

S$/m

etri

c to

n/da

y

mill

ion

US$

Plant Capacity (metric tons/day)

Civil

Machinery

TotalInvestment/capacity

Investment Costs

Plant Capacity (1,000 metric tons of waste/year)

60

90

120

150

180

210

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0 100 200 300 400 500 600 700 800

1,000 metric tons of waste a Year

mill

ion

US$

/yea

r

0

10

20

30

40

50

60

70

800 500 1,000 1,500 2,000 2,500

Metric tons/day

US$

/met

ric

ton

Total costs

Net costs

Income

Net cost/metric ton

Figure 8 Estimated Net Treatment Costs

9 MJ/kg

6 MJ/kg (min. calorific value)

11 MJ/kgDesign load

Min. capacity

Max. capacity

A

B

25.0

180,000 200,000 220,000 240,000 260,000 280,000 300,000 320,000 340,000

35.0

45.0

55.0

65.0

75.0

85.0

Waste Supply (metric tons/year)

Net

Tre

atm

ent C

ost (

US$

/met

ric

ton)

Figure 9 Sensitivity of Incineration Costs

No

Yes

No

Yes

No

Yes

No

Yes

Is a public guarantee forpayment of capital andoperating costsobtainable?

Is foreign currencycommitted/available forcapital and operatingcosts?

Are the regulations forenforcing payment ofwaste charges andenergy in place?

Obtaincommitment

or cancelproject

Cancelproject

Theeconomic

viability is injeopardy

The project iseconomically

viable

Evaluate theconsequencesof introducingincineration

Are the servicedcommunities able andwilling to pay theincineration costs?

No

Yes

Performsensitivity

analysis

Has an economicsensitivity analysis beenconducted and worstcase assessed?

Figure 10 Assessment of Project Economy

Waste with a lower calorific value of 6 MJ/kg only hasa net treatment cost of 30 percent above that of wastewith a lower calorific value of 9 MJ/kg. If the plantprocesses only two-thirds of the design load because ofa shortage of waste or extended periods of maintenance,the treatment cost increases significantly.

Any forecast of the net costs of MSW incinerationshould be conservative and accompanied by a sensitiv-ity/risk analysis. The economic risk, even for fully pri-vatized plants, will end up with the society serviced bythe plant.

The net cost of MSW incineration is significantlyhigher than for landfills established according to strictenvironmental standards. Therefore, the questionwhich must always be asked about any incinerationproject is—why not landfill? Only in situations wherelandfill is not viable (for example, if there is no land, asis the case in Singapore, or if there is no political will tosite a landfill) will WTE be a good choice.

From a strict financial point of view, it may be diffi-cult to justify the increased costs of waste disposal. Afull cost benefit analysis is therefore required to assesswhether the locally obtainable benefits justify the costs.

Recovering the costs of an MSW incineration plantin low to medium income countries is difficult.Depending on the family size, each household may eas-ily generate from 1 to 2 metric tons of waste for incin-eration annually. The net tipping fee at the incinerationplant will therefore amount to at least US$ 50 to 100per year per household. Hence, in some regions, thewaste service charge could be comparable to other pub-lic supply charges such as power and heating. It isimportant to assess the ability and willingness of thepopulation to pay such a treatment charge in additionto the cost of collection and transportation.

The cost of incineration may be recovered through acombination of a tipping fee usually paid by trade andindustry and a general waste management charge usu-ally paid by households and such. The general chargemay be collected directly as a waste managementcharge, or together with other public service bills (suchas electricity or water), or property taxes, and so on. Thecharges may, however, become so great that the normalmarket mechanisms or waste disposal system are dis-torted. The plant may therefore need to be subsidizedvia the budget of the city. Otherwise, it might take strict

enforcement to ensure that waste is taken to the incin-eration plant rather than disposed of indiscriminately.

It is important to design an affordable and publiclyacceptable fee policy, which ensures sufficient incomefor operating, managing, and developing the plant, aswell as a suitable waste flow matching the treatmentcapacity of the plant. Various fee policies are possiblewith adequate support from a combination of fiscaland legal measures. Establishing regional or intermu-nicipal waste management co-operations may provideeconomies of scale that should be compared against theincreased costs of transport.

Key Criteria for Incineration Economy

✓ ✓ ✓ There must be a stable planning environ-ment with predictable prices of consum-ables, spare parts, disposal of residues, andsale of energy. Furthermore, the capitalcosts (large share of foreign currency) mustbe predictable.

✓ ✓ ✓ The financing of the net treatment costmust ensure a waste flow as intended in theoverall waste management system.Consequently, the tipping fee at the wasteincineration plant must be lower or at leastcorrespond to the tipping fee at the landfillsite. Willingness and ability to pay must bethoroughly addressed.

✓ ✓ ✓ Foreign currency must be available to pur-chase critical spare parts.

✓ ✓ When surplus energy is to be used for dis-trict heating, the incineration plant must belocated near an existing grid to avoid costlynew transmission systems.

✓ To be economically feasible, the individualincineration units should have capacities ofat least 240 t/d (10 t/h), and there should beat least two separate units.

✓ If a regular market for sale of hot water(district heating or similar) or low pres-


sure steam is present, the plant should bebased on sale of heat only. This is prefer-able both in terms of technical complexi-ty and economic feasibility. A certainextent of cooling to the environment dur-ing the warm season may be preferable tocostlier solutions.

Project Cycle

The project implementation cycle of MSW incinera-tion plants involves three main phases: feasibilityassessment, project preparation, and project imple-mentation. At the end of each phase, the project shouldbe reevaluated for feasibility.


Phase and Step

Pre-feasibility Study

Feasibility Study

Political Decision

Establishment of anOrganization

Tender and FinancialEngineering

Preparation ofTender Documents

Political Decision

Award of Contract andNegotiations

Construction andSupervision

Commissioning andStart Up

Operation andMaintenance

Purpose and Issues to Consider

Waste quantities, calorific values, capacity, siting, energysale, organization, costs, and financing

Waste quantities, calorific values, capacity, siting, energysale, organization, costs, and financing in detail

Decide on willingness, priority, and financing of incinerationplant and necessary organizations

Establishment of an official organization and aninstitutional support and framework

Detailed financial engineering, negotiation of loans or othermeans of financing, and selection of consultants

Reassessment of project, specifications, prequalification ofcontractors, and tender documents

Decision on financial package, tender documents andprocedures in detail, and final go-ahead

Prequalify contractors, tender documents, selectmost competitive bid, negotiate contract

Construction by selected contractor and supervision byindependent consultant

Test all performance specifications, settlements,commissioning, training of staff, and start up by constructor

Continuous operation and maintenance of plant. Continuous procurement of spare parts and supplies.

Duration

6 months

6 months

6 months

6 months

3 months

6 months

3 months

6 months

2 1/2 years

6 months

10–20 years

Political Decision Decide whether to further investigate or to abort the project 3 months

FeasibilityPhase

ProjectPreparation

Phase

ProjectImplementation

Phase

Figure 11 Typical Implementation Plan

It is important to involve the public throughoutthe project cycle—through awareness campaigns inthe mass media and public hearings on major deci-sions with a direct community impact. Public par-ticipation beyond what is recommended for urbanplanning and environmental impact assessmentmay be useful in dissolving public resistance to theproject.

Feasibility AssessmentThe feasibility of MSW incineration projects in devel-oping countries is highly questionable. Therefore, thefeasibility assessment should be conducted in twostages: preliminary and comprehensive. The prelimi-nary assessment can be based on existing informa-tion, including properly adapted relevant data fromliterature. The comprehensive assessment will involvecomprehensive collection of local data on waste gen-eration and composition, a detailed study of plantfinance and a full environmental impact assessment,for example. Early on, the performance criteriashould be established for the plant’s air pollution con-trol system.

Project PreparationAn appropriate project organization must be estab-lished early in the project preparation phase. In addi-tion, the institutional framework of the facility must beclarified early on.

The project organization will develop appropriateagreements regarding project financing, waste supply,energy sale, and disposal of residues, as well as performthe necessary environmental impact assessments.

The project organization will, furthermore, developproject tender documents and negotiate contracts withsuccessful tenderers.

Since the project organization’s tasks cover a widerange of expertise, independent experts with suitableexperience in the implementation of waste incinera-tion projects must be hired.

Key Criteria for the Project Cycle

✓ ✓ ✓ A skilled independent consultant withexperience from similar projects should beemployed at an early stage.

✓ ✓ ✓ To avoid conflicts, the public should beinvolved and informed during all phases butespecially in the planning phase (feasibilityassessment and project preparation phase).

Project ImplementationThe role of the project organization during implemen-tation will depend greatly on the final institutionalaffiliation of the MSW incineration plant. For a fullyprivatized facility, the project organization must mon-itor project progress and control the contractor’s ful-fillment of all obligations.

For a publicly owned and operated plant, the projectorganization will have to not only monitor and controlthe progress of the actual plant implementation butalso establish the plant management organization. Staffhas to be recruited and trained well ahead of commis-sioning the facility. Start-up assistance, including train-ing of staff and understanding of the operation manu-al, is often included in the supplier’s contract.

Incineration Technology

There are many options for MSW incineration planttechnology. The range of equipment varies from exper-imental to well-proven, though only the well-provenare recommended. Development problems with newtechnology are complicated and costly to solve, asdeveloping countries lack the internal technical exper-tise to overcome them. Such problems could cause theentire project to fail.

Based on the intended application, incinerationplant equipment may be grouped in four main cate-gories:

• Pretreatment• Combustion system• Energy recovery• Flue gas cleaning

The flow diagrams on the last three pages of thisGuide provide a simplified view of how various typesof equipment may be combined. The diagram on ener-gy recovery shows that energy end use is decisive evenfor the choice of boiler type. The Air Pollution Control


diagrams indicate the options for meeting various airpollution standards.

PretreatmentMass burning of “as received”and heterogeneous wasterequires little or no pretreatment such as size reduc-tion, shredding, or fine sorting. Mass burning systemsare typically based on a movable grate.

Mass burning incineration with a movable grateincinerator is a widely used and thoroughly tested tech-nology for waste incineration. It meets the demands fortechnical performance and is capable of accommodat-ing large variations in waste composition and calorificvalue. Another, but less widely applied, mass burningalternative is the rotary kiln.

Some technologies pretreat the waste stream toremove non-carbonaceous materials, such as metaland glass—for example, for production of “refusederived fuel.” These technologies offer some benefits interms of reduced furnace size and improved energyefficiency. However, the front end processing thatshreds and mixes the wastes is demanding and expen-sive. Therefore, the incineration technologies for burn-ing pretreated and homogenized waste are of limiteduse—and historically, such technologies have typicallyfailed.

Theoretically, a fluidized bed may be applied forcombustion of pretreated and homogenized municipalsolid waste. The fluidized bed technology has a num-ber of appealing characteristics in relation to combus-tion technique. The advantages are, however, not thor-oughly proven on municipal solid waste, and thefluidized bed is therefore not recommended. The flu-idized bed may be good for special types of industrialwaste, and for this purpose it is widely applied—forinstance, in Japan.

Combustion SystemWhen implementing a new municipal solid wasteincineration plant, the technology must be based onfeasible and well-proven technology. At present, onlythe mass burning principle with a movable grate fulfillsthis criterion. Furthermore, suppliers with numerousreference plants that have been successful for a numberof years, preferably in low and middle income coun-tries, should be chosen.

The design of the combustion system must hinderthe formation of pollutants, especially NOx and organ-ic compounds such as dioxins, as much as possible.

Energy RecoveryA main benefit of solid waste incineration is the possi-bility of reusing the waste as fuel for energy production.The flue gases carrying the energy released in a wasteincineration furnace have to be cooled in a boilerbefore the air pollution control system. The boiler isalso a necessary technical installation for energy recov-ery. The feasible type of boiler, however, depends onhow the energy will be used: as hot water for districtheating, process steam for various types of industries,or electricity.

The choice between the various end use possibilitiesdepends on the local energy market conditions, including:

• Existing infrastructure for energy distribution—forexample, the availability of a power grid and districtheating network

• Annual energy consumption pattern (the energyoutput from MSW incineration plants is relativelyconstant)

• Prices of the various types of energy and possibleagreements with the consumer(s).

The overall thermal efficiency of an MSW incinera-tion plant equipped for energy recovery depends on theend-use of the energy recovered. Production of elec-tricity has a low thermal efficiency but high-price ener-gy, whereas hot water for district heating is consideredcheap energy with a high overall thermal efficiency andlow cost and technical installation complexity.

The obtainable energy recovery efficiencies appearon the flow diagram at the back of the Guide.

Flue Gas CleaningIncinerating municipal solid waste generates large vol-umes of flue gases. The flue gases carry residues fromincomplete combustion and a wide range of pollutants.The pollutants and their concentration depend on thecomposition of the waste incinerated and the combus-tion conditions. Ash, heavy metals, and a variety oforganic and inorganic compounds can be found invarying quantities.


The pollutants are present in the form of particles(dust) and gases such as HCl, HF, and SO2. Some harm-ful compounds such as mercury, dioxins, and NOx canonly be fully removed by applying advanced chemicaltreatment technologies that increase the overall invest-ment considerably.

The selection of the flue gas cleaning systemdepends primarily on the actual emission standards, ifany, and the desired emission level. In this context thedifferent APC systems can be grouped as basic, medi-um, or advanced emission control.

Basic emission control, in which only the particulatematter is reduced, is simple to operate and maintainand the investment cost is relatively low. At the sametime, a significant part of the most harmful substancesare also retained because dust particles (fly ash) andpollutants absorbed on the surface of the particles canbe removed by equipment such as electrostatic precip-itators. Basic emission control is a minimum require-ment.

By applying relatively simple dry or semidry scrub-bers, medium level emissions can be controlled.

The state-of-the-art flue gas cleaning systems(advanced emission control) applied in, for instance,Europe and the United States, are very complex and thebenefits in terms of reduced emissions should alwaysbe compared to other emission sources.

Removal of dioxins and furans has received muchpublic attention in Europe and North America, whichhas increased installation investments and treatmentcosts.

Incineration ResiduesThe main residue from MSW incineration is slag. Theamount generated depends on the ash content of thewaste. In the combustion process, the volume of wastefrom high income cities will by experience be reducedby approximately 90 percent and the weight by 70 to 75percent. For low income areas the amount of ash in thewaste can be high—for example, in areas using coal,wood, or similar for heating.

In addition to the slag, the plant generates residuesfrom more or less advanced dry, semidry, or wet fluegas cleaning processes. The amount and its environ-mental characteristics will depend on the technologyapplied.

The slag from a well-operated waste incinerator willbe well burnt out, with only a minor content of organ-ic material. Besides, the heavy metals in the slag, whichare normally leachable, will to some extent become vit-rified and thus insoluble. Much of the slag may there-


Table 4: Emission control levels

Saving/cost Emission compared to plant control Parameters designed for medium level controlled control level

Basic Particles only—for example, –10% of total< 30 mg/Nm3. investment

Medium Standard for particle emission.Additional standards for HCl,HF, SO2, and the heavy metals of As, Cd, Cr, Cu, Pb, Mn, Hg,and Ni.

Advanced State-of-the-art emission +15% of total control. Stricter standards for investmentthe medium level parameters and supplementary control ofNOx, the metals Sb, Co, Tl, and V as well as dioxins.

Table 5: MSW incineration flue gases

Emission standard (mg/Nm3, dry, 11% O2)

Parameter Raw flue gas Basic Medium Advanced

Particles 2,000 30 30 10HCl 600 n.a. 50 10HF 5 n.a. 2 1SO2 250 n.a. 300 50NOx (as NO2) 350a n.a. n.a. 200Hg 0.3 n.a. n.a. 0.05Hg + Cd 1.8 n.a. 0.2 n.a.Cd + Tl 1.6 n.a. n.a. 0.05Ni + As 1.3 n.a. 1 n.a.Pb + Cr + Cu

+ Mn 50 n.a. 5 n.a.Sb + As + Pb

+ Cr + Co + Cu + Mn

+ Ni + V 60 n.a. n.a. 0.5Dioxinsb 3 n.a. n.a. 0.1

n.a. = Not applicable in the particular standard.a. Without any primary measures.b.Polychlorinated para-dibenzoe dioxins and furans, ng/Nm3 2,3,7,8-TCDD equivalents

fore be used as road construction material or some-thing similar after sorting.

The other residues must, however, be disposed of.Therefore, a well-designed and well-operated landfill,preferably located in abandoned mine shafts or otherplaces where leaching with rainwater can be preventedmust be available.

Proper disposal of fly ash and other flue gas clean-ing residues is the subject for another study. However,in general, it should be treated as hazardous waste anddisposed of according to leachate properties.

The fine particle size of the residues calls for specialprecautions during handling at the plant and the landfill.

Key Criteria for Incineration Technology

✓ ✓ ✓ The technology should be based on themass burning principle with a movablegrate. Furthermore, the supplier must havenumerous reference plants in successfuloperation for a number of years.

✓ ✓ ✓ The furnace must be designed for stable andcontinuous operation and complete burn-out of the waste and flue gases (CO<50mg/Nm3, TOC<10 mg/Nm3).

✓ ✓ ✓ The flue gases from the furnace must becooled to 200°C or lower before flue gastreatment.

✓ ✓ ✓ The flue gas cleaning equipment must be atleast a two-field ESP (basic emission con-trol, dust<30 mg/Nm3).

✓ ✓ ✓ A controlled landfill must be available forresidue disposal. Full leachate control mustbe exercised at the landfill.

✓ ✓ The annual amount of waste for incinera-tion should not be less than 50,000 metrictons and the weekly variations in the wastesupply to the waste incineration plantshould not exceed 20 percent.

✓ ✓ Municipal solid waste incineration plantsshould be in land-use zones dedicated tomedium or heavy industry.

✓ ✓ The stack should be twice the height of thetallest building within 1.0 km, or at least 70meters high.

✓ See Technical Guidance Report.


Table 6: Salts in leachate from MSW incinerationresidues

Concentration Fly ash and dry + Wet product + level Slag semidry product fly ash

Very Higha Cl Cl, Ca, Na, K, Pb Cl, Na, K

Highb SO4, Na, K, Ca Zn, SO4 SO4, Ca

Mediumc Cu, Mo, Pb Cu, Cd, Cr, Mo Mo

Lowd Mn, Zn, As, Cd, As As, Cr, ZnNi, Se

Very Lowe Cr, Hg, Sn Hg Pb, Cd, Cu, Hg

Max. leaching of ions from incinerator residues, indicativea. Initial concentration > 10 g/L b. 0.1–10 g/Lc. 1–100 mg/L d. 0.01–1 mg/L e. < 0.01 mg/L