World Bank - Waste Incineration

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Municipal Solid Waste

Incineration

The World Bank

Washington, D.C.

W O R L D B A N K

T E C H N I C A L G U I D A N C E R E P O R T
http://cwg%20list.pdf/


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1999 The Internation al Bank for Reconstru ctionand D evelopm ent /THE WORLD BANK

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

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First printin g Augu st 1999

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Cover photo by unkn own


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iii

Foreword v

PART 1 ASSESSMENT 1

1 Introduction 3

Methodology 3

The Flow and Management of Municipal Solid Waste 4

In cin er at io n Pr oject Su m m ar y 4

2 Waste as Fuel 9

Key Issues 9

Waste Gen erat io n an d Co mpo sit io n 10

Heating Value 11

Waste Su rveys/Fo recast s 13

3 Institutional Framework 19

Key Issues 19

Waste Sector 20

Energy Sector 21

Incinerat ion P lan t Organizat ion and Management 21

4 Incineration Plant Economics and Finance 25

Key Issues 25

Econom ics 25

Financing 29

Co st Ben efit Assessm en t 31

5 The Project Cycle 33

Key Issues 33

Feasibilit y Ph ase 33

Pr oject Pr ep ar at io n Ph ase 33

Project Imp lemen tat io n Phase 36

Socio-Economic Aspects and Stakeholder Participation 37

References 41

Contents


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iv Measuring Country Performance on Health

PART 2 TECHNICAL 43

Technical Plant Overview 45

1 Plant Location 47

Key Issues 47

Site Feasib ility Assessment 47

2 Incineration Technology 51

Key Issues 51

Pre-treatm en t of Waste 52

Design and Layout of the Mass Burning Incineration System 54

3 Energy Recovery 59

Key Issues 59

Emergy Recovery Technology 59

4 Air Pollution Control 65

Key Issues 65

Vo lu me an d Co mpo sit io n of the Flu e Gas 66En vir on m en tal St an dar ds 67

Air Po llu t ion Contro l Technology 68

APC System s O ver view 74

In du ced Dr au gh t Fan an d St ack 74

5 Incineration Residues 77

Key Issues 77

Slag 77

Grate Siftings 78

Boiler an d Fly Ash 79

Residues from Dry and Semi-dry Flue Gas Treatment 79Slu dges from Water Treatmen t 80

Spent Adsorben t from Dioxin Filters 80

Other Materials 80

6 Operation and Maintenance 83

Key Issues 83

Typical Plan t Organizat ion and Staffing 83

Crucial Supplies and External Services 85

Training of Workers, Codes of Practice, and Occupational Safety and Health 85

7 Environmental Impact and Occupational Health 87

Key Issues 87Environ men tal Im pact 87

Occu pat io nal Safety an d Health 90

References 93

Municipal Solid Waste Incineration Checklist 95


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v

Foreword

Solid waste management is in crisis in m any of the

worlds largest urban areas as populations attracted to

cities con tinu es to grow. This has led to ever increasing

quan tities of dom estic solid waste while space for dis-

posal decreases. Mun icipal managers are looking to the

developm ent of sanitary landfills aroun d the periphery

of their cities as a first solution. However, siting andpreparation of a landfill requires the acquisition of large

areas as well as good day to day operation in order to min-

imize potential negative environmental impacts.

Another approach that has recently caught the attention

of decisionm akers is mass burn incineration similar to

systems found in the O ECD countries. However, capital

and operatin g requirements for th ese plants are general-

ly an order of magnitude greater than required for land-

fills. Project developers armed with rosy financial fore-

casts can be found in all corners of the globe encouraging

municipal officials to consider incineration.In order to assist local officials with developing cost

effective strategies for d ealing with solid waste manage-

ment, the World Bank has begun a program of provid-

ing high level advice on approaches that are basically

finan cially self suppo rt ing, socially and environm ental-

ly responsible. This Technical Guidance Reportprovides

the foundation for such a detailed evaluation of solid

waste incineration systems. A docum ent for making a

more preliminary assessment is the accompanyingDecision Makers Guide to Incineration of Municipal

Solid Waste.

This report shou ld be used with caution since both

techn ical and fin an cial feasibility are very site-specif-

ic. Readers with general interest and technical spe-

cialists will find this report useful in making their

assessment s. A com prehen sive solid waste man age-

m ent pr ogram m ay include several option s phased in

over a long period of time dur ing which refuse quan-

tities, constituents and the overall economic picture

m ay change significant ly. This uncertain ty and asso-ciated risks must be incorpor ated into the p lann ing

process.

Kristalina Georgieva

Sector Man ager

Environm ent an d Social

Development Sector Unit

East Asia an d Pacific Region

The World Bank

Washington, DCUSA

Keshav Varma

Sector M anager

Urban D evelopm ent

Sector Un it

East Asia and Pacific Region

The World Bank

Washington, DCUSA


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The Report was made possible through the generous

support of the Danish governm ent. The report was

prepared by Mr. J. Haukohl, Mr. T. Rand and Mr. U.

Marxen of Rambll.Th ree people were instrum ental in

encouraging the preparation of these publications,

Lars Mikkel Johann essen, currently with the D anish

government, Dr. Carl Bartone, Principal Environ-mental Specialist and Gabr iel Boyer. The Task Man ager

for this work was Jack Fritz, Environm ental Engineer.

The editors were Mellen Candage and Carol Levie of

Gramm arians, Inc.

In addition to internal reviewers, we also than k the

external peer reviewers for th eir time an d comm ents,

specifically Stephen Schwarz, PE of Malcolm Pirn ie,

Inc. and Anil Chat ter jee, PE of Chat ter jee andAssociates.

vi

Acknowledgments


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vii

Abbreviations and Symbols


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A Ash content per kg of d ry sam ple

APC Air pollution con trol

BO Build and operate

BOO Build, own, and operate

BO OT Bu ild , o wn , o p er at e, t ran sfer

C Com bustion fractionC Degrees Celsius

CBA Cost ben efit assessm en t

CH P Com bined heat an d power

DBO D esign , build, an d operate

DC Direct current

DS Dry substance

EA Environm ental assessm ent

EIA En viron m en tal im pact assessm en t

ESP Electrostatic p recip itator

EU European Union

GDP Gross dom estic productGR Growth rate

GWh Gigawatt hour

h Hour

H awf Ash and water free calorific value

H in f Lower (in ferior) calorific value

H inf, overall Overall lower calorific value

H RD H um an resou rce develop men t

H sup Upper (superior) calorific valueH sup,DS Superior calorific value of dr y samp le

kcal Kilocalories

K Kelvin

KF Key figure

kJ Kilojoule

kPa Kilopascal

LCV Lower calorific valu e

LOI Loss of ignition

LP Low pressure

m Meter

MCW Weight of condensed water per kg of drysample

m g Milligram s

viii Municipal Solid Waste Incineration


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1

PART 1

ASSESSMENT


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Th e Technical Guidance Report provides back-

ground information for the Decision Makers Guide

to Municipal Solid Waste (MSW) Incineration. The

Report focuses on large-scale incineration plants

for large urban areas or intermunicipal coopera-

tives. It does not addr ess hazardou s and infectious

wastes.The Decision Makers Guide is a practical tool for

a prelim inary assessment o f whether th e key crite-

ria for a solid waste incineration scheme are pre-

sent.

Th e Technical Guidance Report provides decision

m akers and th eir advisers with m ore elaborate infor-

m ation on how to investigate and assess the degree to

which the key criteria are fulfilled. Hence, the Report

compr ises a com prehensive accoun t of m any aspects

of waste incineration. Part 1 of the Report provides

inform ation n eeded to assess the feasibility of MSWincineration. Part 2 covers techn ical aspects and the

available techn ologies related to an M SW incinerat ion

plant.

Th e Decision Makers Guide pr imar ily addr esses

an aud ience at the polit ical level, whereas the

Technical Guidance Report presumes some degree

o f gen er al t ech n ica l k n ow led ge. H o wever, n o

expertise within th e field of waste incineration is

required to unders tand the Technical Guidance

Report.

Finally, note that the Technical Guidance Report isfar from being a design man ual for an M SW in cinera-

tion plant. The responsibility, the final feasibility

assessment and the consecutive design of such a plant

mu st be entr usted to experienced consultant s and sup -

pliers with an extensive track record in this comp lex

subject.

Methodology

Th e Technical Guidance Report is organized as

follows:

Part I

In trod u ct io n

Waste as Fuel

Institutional Framework

Incineration Plant Econom ics and Finance

The Project Cycle

Part II

P lan t Locat ion

Incineration Technology

Energy Recovery Air Pollution Control

Incineration Residues

Operation and Maintenance

Environmental Impact and Occupational Health

Each chapter is stand ardized to m ake inform ation

easy to access, as follows:

Key issuesMain points, critical issues, and deci-

sions to be m ade.

Key criteriaKey criteria are listed in order ofimpo rtan ce, using the following sym bols to empha-

size prior ity:

Mandatory

Strongly Advisable

Preferable

3

1 Introduction


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If any mand atory key criteria are not expected to be

fulfilled, it is advisable to stop plan nin g the solid waste

incineration plant.

General principlesElaboration of the general con-

siderations.

Th e Technical Guidance Report is supp lem ented by

an evaluation checklist for decision makers who are

considering MSW incineration as part of their waste

management strategy.

Furthermore, as an introduction, the following two

sections provide a brief overview of the flow and m an-

agement of mu nicipal solid waste, objectives and

applicability of waste incineration, and th e necessary

institutional framework.

The Flow and Management of Municipal

Solid Waste

Solid waste arises from human activitiesdomestic,

comm ercial, indu strial, agricultural, waste water treat-

ment, and so on. If the waste is not properly handled

and treated, it will have a negative impact on t he

hygienic conditions in urban areas and pollute the air

and surface and groun d water, as well as the soil and

crops.A hygienic and efficient system for collection and

disposal of solid waste is therefore fund am ental for any

comm un ity. Generally, the deman ds on the solid waste

man agement system increase with th e size of the com-

mu nity and its per capita incom e. Figure 1.1 shows that

the fin al destination o f waste is always a disposal site.

Residues from waste treatment processes are returned

to the waste m ainstream an d end up in the landfill with

untreated waste. Hence, the backbone of any waste

management system is an efficient collection system

and an environm entally sound sanitary landfill.The systems resource recovery and recycling reflect

that solid wastes are materials and by-products with

potentially negative value for the possessor.

Und erstand ing what m ay be considered waste will thus

change with the circum stances of the po ssessor as well

as in t ime and p lace. Waste may be transform ed into a

resource simply by transportation to a new place or

through treatment. Such a tr ansform ation depends on

the costs involved an d wheth er th e econ om y is looked

upon as a private business, a national priority, or even

globally.

Waste treatment involving mechanical plants

requires large investm ents and operating costs. Hen ce,it should be only introduced after gaining profound

knowledge of the existing system and waste genera-

tion which is quite a challenge, except in a highly

organized waste management system. The most

impo rtan t factor in obtaining such inform ation is that

the waste is already disposed of in fully m on itored an d

contr olled landfills only.

Incineration Project Summary

MSW incineration is foun d at the m ost advanced level

of the waste disposal/treatm ent hierarchy: indiscrim i-

nate dum ping, controlled dum ping, landfilling, sani-

tary landfilling, and m echanical treatment (for exam-

ple, comp osting and incineration). Additional envi-

ronm ental cont rol is intr oduced at each level and t he

disposal costs increase substantially. Introd ucing

m echanical treatment of MSW entails a significant

jum p in technolo gy and costs an d is gen erally on ly fea-

sible when all waste is already being disposed of in a

sanitary landfill established and o perated accordin g toDecision Makers Guide to Solid Waste Landfills, WB/1/ .

Even so, m any things can cause the project to fail and

leave society with a hu ge bill to pay.

Deciding to incinerate waste instead of, for instance,

dum ping it, takes careful consideration of the criteria

for success. In the mid 1980s, a number of Eastern

European and Asian cities jumped directly from sim-

ple dum ping to M SW incineration. Any success was,

however, questionable in many of these cities. In the

former Soviet Union, several plants were com mis-

sioned in t he late 1970s and early 1980s.Un fortu nately,some of these plants were never completed, others were

discontinu ed, and the rest are operating at reduced

capacity because of financial, managerial, and opera-

tional shortcom ings.

In Asia, th ere is limited experience with waste incin-

eration outside the industrialized count ries of Japan,

Singapore, and Taiwan. A few plants in other places

4 Municipal Solid Waste Incineration


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have experienced m anagerial, financial, or op erational

problems, including low calorific value of the waste due

to scavenging, precipitation, or th e basic com position

of the generated waste.

The failure of MSW incineration plants is usually

caused by one or m ore of the following:

Inability or unwillingness to pay the full treatment

fee, which results in insufficient revenu e to cover

loan installments and operation and maintenance

costs

Lack of convertible currency for purchase of spare

parts

Operation and maintenance failures (including lack

of skilled workers)

Problems with the waste characteristics and quan-

tity

Poor plant management

Inadequate institutional arrangements Overly optimistic projections by vendors.

Objectives and Applicability of MSW Incineration

In highly industrialized Europ ean coun tries, waste

incineration plants have been used increasingly over

the last 50 years, m ainly because it has been m ore dif-

ficult to fin d n ew sites for landfills in d ensely popu lat-

Introduction 5

FinalProduct

PrincipalTechnologies

Principal SolidWaste Activities

Production, trade,and consumption

RecyclingSortingSolid waste

Collection

Transfer stationsTransportation

Manual sorting

Recycling

Mechanical sortingTreatment (optional)

Soil improverComposting

EnergyIncineration

Scavenging Recycling

Land reclamationDisposal / landfill

Figure 1.1 Solid waste handling and treatment system components


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ed areas. The public concern for the environm ental

impact of MSW incineration h as, however, increased

significant ly over the last 20 yearsforcing th e man u-

facturers to develop, and t he plants to install and oper-

ate, high-cost advanced technology for p ollution con-

tro l (especially air po llution) .Incineration of MSW does not comp letely elimi-

nate, but d oes significantly reduce, the volum e of waste

to be landfilled. The reductions are approximately 75

percent by weight and 90 percent by volum e. The

residues arising from air pollution control (APC) are,

however, environm entally prob lem atic, as they p resent

a severe threat to ground and surface waters. Current

techn ology is supp osed to d ispose of such residues in

highly controlled sanitary landfills equipped with

advanced leachate collection and treatment measures,

or in form er und erground m ines to prevent leaching of

heavy metals and, for som e APC residues, chlorides.

Fear of pollution often br ings MSW incineration

plants to the center of emotion al pub lic debate.

Incinerating solid waste fulfills two p ur poses in th e

advanced waste m anagement system. Primarily, it

reduces the amo un t of waste for sanitary landfilling;and it uses waste for energy production (power or dis-

trict heating). Hence, waste incineration plants are

generally intro du ced in areas where the siting of sani-

tary landfills is in conflict with o ther interests such as

city developm ent, agriculture, and tou rism.

Solid waste incineration is a highly com plex techn ol-

ogy, which involves large investm ents and high o perat-

ing costs. Income from sale of energy makes an imp or-

tant (and necessary) contribution to the total plant

econo my,an d, consequently, the energy market plays an

imp ort ant ro le in deciding whether to establish a plant.


Figure 1.2 Exploded view of typical MSW incineration facility (mass burning)


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Several types of incinerat ion t echnologies are avail-

able today, and t he m ost widely used is mass burnin g

incinerationwith a movable grate or, to a lesser

extent , rotary kilns. Fluidized bed incinerat ion is still at

the experimental stage and should th erefore not yet be

applied. The m ass bur ning technology with a m ovablegrate has been successfully applied for decades and was

developed to com ply with t he latest techn ical and envi-

ronm ental standards. Mass bur ning incineration can

generally handle municipal waste without pre-treat-

ment o n an as-received basis.

Mass burnin g techn ologies are generally applied for

large-scale incineration o f m ixed or source-separated

mu nicipal and indu strial waste. Com pared to movable

grates the rotar y kiln incineration p lants have a small-

er capacity and are mostly used for special types of

waste unsuitable for b urn ing on a grate, such as vari-ous types of hazardous, liquid, and infectious waste.

Institutional FrameworkOverview

When considering the constru ction of an incineration

plant , it is necessary to consu lt with m any project stake-

holder s. The relevant stakeholders are usually auth or i-

ties, the waste sector, comm un ity groups, and th e ener-

gy sector. A fur ther subdivision of these stakeholders

appears below.

It is impo rtant to review possible local stakeholders

based on the actual local conditions, political and

financial situation, and other current and planned

waste treatm ent and disposal facilities.

The most impor tant issue, financially, could be

generation of revenue from the sale of heat or power

(or b oth ), as well as the possibility of collecting fees

from comm ercial, dom estic, and pu blic waste gener-ators.

Environm entally, impo rtan t issues may be to define

suitable standards for flue gas emissions, quality and

disposal of solid outpu ts (slag, ash, and flue gas clean-

ing residuals), as well as waste water in case a wet flue

gas cleaning system is applied.

The most important question, institutionally,

could be how to control the waste flow for optimum

treatm ent and u tilization of the available waste treat-

ment and d isposal facilities; and h ow to ensure the

institutional and managerial capacity required tooperate a multiple stringed waste management sys-

tem.

Depending on local traditions and the level of envi-

ronm ental awareness, a special and t ransparent infor-

m ation cam paign could be carried out for com mu nity

groups an d neighboring citizens.

The goals, strength, resources, and awareness of the

stakeholders often differ among each other and with

those of the proposed incineration plant owner/oper-

ator. Reaching a solutio n th at is acceptable to all m ay

be difficult.

Introduction 7

Energy Sector

Power producers

Power distribution company

Industries selling heat/power

District heating company

Power/energy consumers

Community

Environmental NGOs

Nature/Wildlife NGOs

Community groups

Neighboring citizens

Scavengers

Waste Incineration Plant

Waste Sector

Waste generators

Waste recycling companies

Waste collection companies

Other treatment plants

Landfill operators

Authorities

Local/provincial governmentUrban/regional planning

Environment authorities

Health authorities

Traffic authorities

Figure 1.3 Typical MSW incineration project stakeholders


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Key Issues

The successful outcom e of a waste incinerat ion project

first depen ds on fairly accur ate data on the futu re waste

quantities and characteristics that form the basis for

the design of the incineration plant.

Waste for incineration must meet certain basicrequirements. In particular, the energy content of the

waste, the so-called lower calorific value ( LCV), m ust

be above a m inimu m level. The specific com position of

the waste is also im por tant. An extrem e waste compo-

sition of only sand and plastics is not suitable for incin-

eration , even tho ugh th e average lower calor ific value

is relatively high. Furtherm ore, in order to operate the

incineration plant continuously, waste generation

must be fairly stable du rin g the year.

Hence, the amount and composition of solid waste

generated in th e collection area for a po tent ial inciner-ation plant, and possible seasonal variations, mu st be

well established before the pro ject is laun ched. Waste

comp osition dep ends on variables such as cultural dif-

ferences, climate, and socio-econom ic conditions.

Therefore, data usually canno t be tr ansferred from one

place to another.

All waste studies and forecasts must focus on the

waste ultimately supplied to the waste incineration

plant. Consequently, the effect of recycling activities

(for example, scavengers) that change the comp osition

of the waste must always be con sidered.In m any developing countr ies, the dom estic waste

has a high moisture or ash content (or both).

Therefore, a comprehensive sur vey must be taken to

establish wheth er it is feasible to inciner ate year-rou nd ,

as seasonal variation s may significantly affect th e com-

bustibility of the waste.

Waste from industries and the commercial sector

(except for m arket waste) generally has a much h igher

calorific value th an d om estic waste. However, collec-

tion of such wastes is often less organized or contr olled,

and delivery to an incineration plant can be difficult.

Some types of waste, such as demolition waste and

waste containing certain hazardous or explosive com-poun ds, are not suitable for incineration.

The waste comp osition m ay change in tim e because

of either additional recycling or econom ic growth in

the collection area. Both chan ges can significantly alter

the amo un t of waste and its calorific value.

Key criteria

The average lower calorific value of the

waste must be at least 6 MJ/kg throughout

all seasons. The annu al average lower

calorific value mu st not be less than 7 MJ/kg.

Forecasts of waste generation and composi-

tion are established on th e basis of waste

surveys in the collection area for the

planned incineration plant. This task mu st

be carried out by an experienced ( and inde-

pendent) institution.

Assum ptions on the delivery of com-

bustible indu strial and comm ercial waste to

an incineration plant should be founded onan assessm ent of positive and negative

incentives for the various stakeholders to

use the in cineration facility.

The annual amou nt of waste for incineration

should not be less than 50,000 metric tons

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2 Waste as Fuel


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and the weekly variations in the waste sup ply

to th e plant shou ld not exceed 20 percent.

Waste Generation and Composition

The quantity and composition of solid waste depend

on h ow developed the comm un ity is and the state of its

econom y. Indu strial growth is an impor tant tool for

raising the per capita income and welfare of the pop u-

lation. In return , industrial growth and higher per capi-

ta income generate more waste, which, if not p roperly

controlled, causes environm ental degradation.

Key figures for generation of mu nicipal solid waste

(M SW) app ear in Table 2.1. MSW is collected by, or on

the order of, the author ities and com m only compr ises

waste disposed of at m un icipal collection facilitiesfrom hou seholds, comm ercial activities, office build-

ings, public institutions, and small businesses. The

actual definition of mun icipal solid waste m ay, how-

ever, vary from place to p lace.

Urbanization and r apid growth of cities increase the

amou nts of waste generated in limited and densely

populated areas. This, in turn , may eliminate the pos-

sibility of inexpensive disposal metho ds.In m ore rur al areas, crops and animal wastes are

increasing as pesticides and fertilizers are applied

more often. However, many of these biodegradable

materials may be burned as fuel or easily converted

into a soil condition er and shou ld not be regarded as

tru e waste.


Table 2.1 Key figuresmunicipal solid waste (kg/capita/year)

Waste generation

[kg/cap./year] Annual

Area Ref. Range Mean growth rate

OECDtotal /2/ 263864 513 1.9%

North Am erica /2/ 826 2.0%

Japan /2/ 394 1.1%

OECDEurope /2/ 336 1.5%

Europe (32 countries) /3/ 150624 345 n .a.

8 Asian Capitals /4/ 1851000 n.a. n.a.

South and West Asia

(cities) /5/ 185290 n.a. n .a.

Latin America and

the Caribbean /6/ 110365 n.a. n.a.

Domestic Waste Waste from hou sehold activities, including food preparation, cleaning, fuel bur ning, old

clothes and furnitu re, obsolete utensils and equipmen t, packaging, newsprint, and garden wastes.

In lower-income coun tries, dom estic waste is dom inated by food waste and ash. Middle- and h igher-income countr ies have a larg-

er proportion of paper, plastic, metal, glass, discarded items, and hazardous matter.

Commercial Waste Waste from shops, offices, restaurants, hotels, and similar com mercial establishments; typi-

cally consisting of packaging m aterials, office supp lies, and food waste and bearing a close resemblance to d om estic waste.

In lower-income countr ies, food markets may contribu te a large propor tion of the comm ercial waste. Com mercial waste may

include hazardous comp onent s such as contam inated packaging m aterials.

Institutional Waste Waste from schools, hospitals, clinics, governm ent offices, military bases, and so on. It is

similar to bo th d omestic and com mercial waste, although th ere is generally more packaging m aterials than food waste. Hospital and

clinical waste include potentially infectious and h azardous materials. It is imp ortan t to separate the hazardou s and n on- hazardous

compo nents to redu ce health risks.

Industrial Waste The compo sition of indu strial waste depends on the kind o f indu stries involved. Basically,

indu strial waste includes compo nents similar to d om estic and comm ercial source waste, including food wastes from kitchens and

canteens, packaging materials, plastics, paper, and m etal items. Some production pro cesses, however, utilize or generate hazardous(chemical or infectious) substances. Disposal routes for hazardou s wastes are usually different from those for n on-h azardous waste

and depend on the comp osition of the actual waste type.

Street Sweepings This waste is domin ated by dust and soil together with varying amoun ts of paper, metal,

and o ther litter from the streets. In lower-incom e countr ies, street sweepings may also include d rain cleanings and dom estic waste

dum ped along the roads,p lant remains, and animal manure.

Construction and Demolition Waste The composition of this waste depends on the type of building materials, but typically

includes soil, stone, brick, concrete and ceramic materials, wood, packaging materials, and the like.


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Generally, construction, demolit ion, and street

sweeping wastes are not suited for inciner ation .

The composition of the various types of MSW varies

greatly by climate and seasonal variations and the

socio-econ om y of the waste collection area.

In general, high-income areas generate more wastethan low- or middle-income areas. Thus, waste gener-

ation and composition may differ greatly even within

the same m etropolis.

Waste collected in affluent areas is typically less

dense, as it contains m ore packaging and o ther lighter

materials and less ash and food waste. This is because

mo re ready-made produ cts are consum ed and the food

processing takes place in the commercial/industrial

sector.

The m oisture is greater in lower-in come areas due to

the water content of the food waste and smalleramounts of paper and other dry materials. Annual

variations in m oisture content depend on climatic con-

ditions such as precipitation and harvest seasons for

vegetables and fruit.

Examples of the composition of waste from China,

the Philippines, and European coun tries are presented

in Table 2.2.

Heating Value

On ce ignited, the ability of waste to sustain a combu s-

tion p rocess without supplementary fuel depends on a

num ber of physical and chemical param eters, of which

the lower (inferior) calorific value (H in f) is the most

important. The minimu m required lower calorific

value for a contr olled incineration also depends on the

furn ace design. Low-grad e fuels requ ire a design th at

m inim izes heat loss and allows the waste to dr y beforeignition.

During incineration, water vapors from the com-

bustion process and the mo isture content of the fuel

disperse with the flue gasses. The energy content of the

water vapors accounts for the difference between a

fuels up per and the lower calor ific values.

The up per (superior) calorific value (H sup) of a fuel

m ay, according to DIN 51900, be defined as the energy

content released per unit weight through total com-

bustion of the fuel. The temp erature of the fuel before

combustion and of the residues (including cond ensedwater vapors) after combustion m ust be 25C, and th e

air pressure 1 atm osphere.Th e com bustion m ust result

in complete oxidation of all carbon and sulfur to car-

bon - and sulfur d ioxide respectively, whereas no oxi-

dation of nitrogen mu st take place.

The lower calorific value differs from the upper

calorific value by the heat of condensation of the com-

bined water vapors, which comes from the fuels mois-

ture content an d th e hydrogen released throu gh com-

bustion.

The ash an d water free calorific value (H awf) express-es the lower calorific value of the combu stible fraction

(ignition loss of dr y samp le) as stated on page 12.

Waste as Fuel 11

Table 2.2 Composition of municipal wastes (percentage of wet weight)

% of waste Guangzhou, China, 8 districts Manila 22 European Countries

Year 1993 1997 1990

Ref. /7/ /9/ /3/

Fraction Range Mean Mean Range Mean

Food and organic waste 40.1 71.2 46.9 45.0 7.2 51.9 32.4

Plastics 0.9 9.5 4.9 23.1 2 15 7.5

Textiles 0.9 3.0 2.1 3.5 n.a. n.a.

Paper & cardboard 1.0 4.7 3.1 12.0 8.6 44 25.2Leather & rubber .. .. 1.4 n.a. n.a.

Wood .. .. 8.0 n.a. n.a.

Metals 0.2 1.7 0.7 4.1 2 8 4.7

Glass 0.8 3.4 2.2 1.3 2.3 12 6.2

Inerts (slag, ash, soil, etc.) 14.0 59.2 40.2 0.8 .. ..

Others .. .. 0.7 6.6 63.4 24.0

Notes: n.a. = Not applicable

.. = N egligib le


20/111

As a rule of thumb, H awfm ay be estim ated at 20,000

kJ/kg for ordin ary MSW, except wh en th e waste con-

tains extreme amou nts of a single m aterialsuch as

polyethylenewhich has about double the energy

content.

Municipal waste is an inhomogeneous fuel that dif-

fers greatly from convent ional fossil fuels. Calculating

the calorific value of MSW is, therefore, complex andmay lead to gross errors if done incorrectly. The repre-

sent ativeness of the samples analyzed is most critical,

and variations mu st be accounted for.

Assuming that it is not possible to assess the fuel

characteristics of a particular waste from test r un s at an

existing waste incinerat ion plant , m ore or less sophis-

ticated evaluation m ethods m ay be applied.

A first indication may be obtained simply by estab-

lishing the following three parameters (in percentage

by weight) :

A: Ash content (ignition residuals)

C: Combustible fraction (ignition loss of drysample)

W: Moisture of raw waste

The lower calorific value of a fuel m ay then be cal-

culated from t he following:


Determination of Hawf

1. In a laboratory, the upper calorific value of the dry sample H sup,DS is determ ined according to DIN 51900.

2. H awf is then d etermin ed accord ing to the following form ula:

H awf= H inf,DS/ ( 1A) * M CW * 2445 in kJ/kg,

where A is the ash content p er kg dry samp le and MCW is the weight of the cond ensed water per kg dry sam ple.

80

70

60

50

80 9070605040

C=25

%

302010

90 A=4-%

80

70

60

10

20

30

40

50

40

30

20

10

90

% Moisture (W)

% Combustible (C)% Ash (A)

W=50%

Figure 2.1 Tanner triangle for assessment of combustibility of MSW


21/111

H in f= H awf * C 2445 * W in kJ/kg

Assumin g that th e waste has no d om inant fraction

with an extremely low or h igh calor ific value, th e lower

calor ific value may be obtain ed by applying an app rox-

imate value of 20,000 kJ/kg for H awf:

H in f 20,000 * B - 2445 * W in kJ/kg

The result m ay also be p lotted in a Tanner tr iangle dia-

gram to see where it falls within the shaded area indicat-

ing a combustible fuel (Figure 2.1). The waste is theoreti-

cally feasible for combustion with out auxiliary fuel when:

W < 50 percent, A < 60 percent, and C > 25 percent.

A more accurate way to assess the fuel quality of a

waste is to divide it into characteristic components

(organic waste,p lastics, cardboard, inerts,an d t he like),determ ine the water content (%W ), the ash content

(%A) and the combustible matter (%C). The lower

calor ific value for each compon ent can be found in lab-

oratory or literature values for H awf for that comp o-

nen t. Finally, the overall lower calor ific value and ash

content are calculated as the weighted average for all

components.

Table 2.3 provides examp les of the results of this

simp le waste analysis,as well as th e lower calor ific value

determined as the weighted average of the heat valuefor characteristic com pon ents of the waste. The waste

from M anila has the highest com bustible content and

calorific value.

The m ethod o f calculating the calorific value as the

weighted average of characteristic fractions of the

waste is further illustrat ed in Table 2.4.

See Waste Sur vey, page 17, for m ore accur ate liter-

atur e values on H awf.

Waste Surveys/Forecasts

Estimating the amo unt and composition of solid

waste requires in-dept h knowledge of the waste col-

lection areas dem ographic and comm ercial/industr i-

Waste as Fuel 13

Table 2.3 Fuel characteristics of municipal wastes

Guangzhou China

8 districts-93 /7/ 5 districts-94 /8/ Philippines

Parameter Units Range Mean Mean Manila - 97 /9/

Com bustible % 14.6 25.5 22.3 31.4 37.6

Ash % 13.8 43.1 28.8 22.0 15.6

Moisture % 39.2 63.5 48.9 46.6 46.7

Lower calorific value kJ/kg 2555 3662 3359 5750 6800

Table 2.4 Example of calculation of lower calorific value from analysis of waste fractions and Hawfvaluesfrom literature

Mass basis Fraction basis Calorific values

% of Moisture Solids Ash Combustible H awf HinfFraction Waste W % TS% A% C% kJ/kg kJ/kg

Food and organic waste 45.0 66 34 13.3 20.7 17,000 1,912

Plastics 23.1 29 71 7.8 63.2 33,000 20,144Textiles 3.5 33 67 4.0 63.0 20,000 11,789

Paper & cardboard 12.0 47 53 5.6 47.4 16,000 6,440

Leather and rubber 1.4 11 89 25.8 63.2 23,000 14,265

Wood 8.0 35 65 5.2 59.8 17,000 9,310

Metals 4.1 6 94 94.0 0.0 0 147

Glass 1.3 3 97 97.0 0.0 0 73

Inerts 1.0 10 90 90.0 0.0 0 245

Fines 0.6 32 68 45.6 22.4 15,000 2,584

Weighted average 100.0 46.7 53.3 10.2 43.1 7,650


22/111

al stru cture. Reliable waste generation d ata and fore-

casts are scarce in m ost coun tries. Data and key figures

are often related to the overall waste generation/dis-

posal of large cities and m un icipalities. Significant dif-

ferences will, however, exist between waste generatio n

and composition in a citys various zones such as itshigh or low income residential, comm ercial and

indu strial areas.

Literature is available on key figures for waste gen-

eration and com position. When p roperly selected and

applied, such data m ay be used for a prelimin ary assess-

ment of the feasibility of various waste treatment

methods. For design pu rposes, however, it is best to

establish and ap ply specific data for the area. It is rec-

ommended that waste quantity and quality be sur-

veyed year-round to monitor the seasonal variation

both in am oun ts and in waste characteristics. This maybe particularly important in regions with distinct

tour ist seasons, high mon soon rains, and the like.

Waste Forecasts

To be econom ically feasible, waste incinerat ion p lants

mu st have a life span of at least 15 to 20 years. Waste

quant ity and comp osition shou ld be forecast over the

lifetime of the incineration plant. A waste generation

forecast requires a com bination of data no rm ally used

for town planning purposes along with specific waste

generation data.Chan ges in waste composition will be influenced by

govern ment r egulations of issues such as recycling and

the overall econom ic developm ent of society. However,

possible developm ent tr ends m aybe obtained by study-

ing the waste composition in d ifferent p arts of the same

metropolisfor instance,in high-, medium-, and low-

incom e areas. Literatu re on investigations from similar

societies may also be u seful. Annu al variations are like-

ly to continu e according to the p resent p attern.

As an example, the forecast for th e dom estic waste

for th e year (n ) m ay be calculated accord ing to th e for-

mu la below. Variables include the p resent popu lation,the expected long-term annu al growth, the m ost recent

waste generation key figure, and t he foreseen increase

in th is figure.

Dom estic waste = PP (1+ GRPP)n wc (1+GRKF)

n

PP is the present p opu lation, GR the growth rate and wcis the actual key figure, waste generation per capita.

If available, the per capita generation key figure (wc)should be determined by assessing reliable existing

waste data. If reliable data is not available, an accurate

waste sur vey should be carr ied ou t. An examp le of per

capita generation key figures are shown in Table 2.6.

Waste Survey

If reliable waste data an d recordkeeping systems are not

available, a waste sur vey should be used to generate sta-

tistically significant results. The sur vey mu st consider a

large num ber of param eters selected according to the

objective of the studyfor exam ple, waste quant ity orcomp osition. Also, to detect seasonal variations, the

survey should be performed all through the year.

Generally, continuou s reliable waste data recording

and recordkeeping are important for developing real-


Table 2.5 Waste generation forecast parameters

Parameter Development trend

Population Growth/year (overall and bydistrict)

Industrial employment/industrial

area build up Growth/year

Commercial sector employment Growth/year

Gross domestic product (GDP) Annual general prosperity

growth

Wast e gen er at io n key figu res Gr owt h/ year

Waste composition Function of socio-econom ic

development

Table 2.6 Per Capita Generation Data for SelectedCountries

Estimated Domestic Waste Generation

Country Year Ref. kg/capita/day

China general 199096 /10/ 0.5cities 199096 /10/ 0.81.2

USA 1990 /11/ 2.0

1985 /11/ 1.8

Japan 1990 /11/ 1.1

1985 /11/ 1.0

France 1990 /11/ 1.0

1985 /11/ 0.8

Denm ark 1996 /12/ 1.5

1990 /12/ 1.0


23/111

istic waste management p lans, m onitorin g the effects

of waste management strategies, and pu blicly control-

ling waste flows and t he performan ce of waste man-

agement organizations.

The degrees of freedom are statistically reduced

when the sampling point moves away from the originof the waste and towards the disposal sitethat is,

fewer samp les are required to obt ain th e desired preci-

sion of the data. In return, a number of systematic

errors m ay be intr oduced. For exam ple,scavenging and

oth er recycling activities will redu ce weight an d ch ange

the composition of the waste. In developing coun tries,

where there is much scavenging, the calorific value of

the waste may be redu ced considerably due to r ecovery

of wood, plastic,textiles,leather, cardboard, and paper.

Plus, the weight of the waste m ay be influenced by cli-

matic cond itions on its way from the point o f origin toultimate disposal. Dur ing dry seasons, weight is lost

throu gh evaporation, and precipitation dur ing the wet

season m ay increase the weight.

Waste QuantityKey Figures and Annual Variation

For well-organized waste management systems where

mo st of the waste ends up in controlled landfills, long-

term system atic weighing of the incom ing waste will

allow a good estimate of the key figures for waste gen-

eration and the annu al variation. Thus, landfills and

other facilities receiving waste must have weighingbrid ges to p rod uce reliable waste data.

To establish waste generation key figures, waste

quan tity shou ld be registered systematically and fairly

accur ately. For every load, th e collection vehicles mu st

submit inform ation about th e type of waste and its ori-

gin. Further inform ation about the district where the

waste was collected can be obtained from town plan-

nin g sou rces and t he socio-econ om ic aspects can con-

sequently be included in the key figure calculations.

Table 2.7 indicates how a waste collection area m ay be

divided into collection districts to reflect characteris-

tics of waste generation.

In places with n o waste registration records, typical

districts may be ou tlined accord ing to Table 2.7. Then ,

the collected waste should be systematically weighed.

The registration shou ld contin ue for at least a full yearto detect any seasonal variations. Great care m ust be

taken to en sure that no changes are introdu ced in th e

collection districts, which could make the results

ambiguous.

Introd ucing a waste incineration p lant will reduce

the livelihoo d of landfill scavengers. They may move to

a new place in front of the treatment p lant, thus chang-

ing the composition and calorific value of the waste. It

is impo rtan t to assess the im pact of such a change,

according to the amount the scavengers remove at the

existing landfill.

Waste Composition

Waste composition varies with th e waste type, the

socio-econom ic conditions of the collection area, and

seasonal variation s. Plann ing a comprehen sive survey

of the composition of waste types therefore requires

input from a town planner, a waste management

expert, and a statistician.

The sur vey planners shou ld do at least the following:

Divide the waste collection area into zones accord-ing to land use.

Subdivide land-use zones according to types of

waste generated (see Table 2.6).

Identify well-defined and representative waste col-

lection districts for the t ypes of waste.

Choose one or m ore representative districts to sur-

vey for each typ e of waste.

Select the point of waste interception in such a way

that the waste will reflect what will reach a future

treatmen t facility or incineration p lant.

Waste as Fuel 15

Table 2.7 Waste types and collection districts

Waste type Collection District

Dom estic High incom e Medium incom e Low incom e

Com mercial Shopping/office com plexes Departm ent stores Markets

Industrial Large enterprises Medium industries Small industries


24/111

Establish baseline data for the district (pop ulation,

industry, trade, and such).

Monitor the amount of waste generated in the dis-

trict and the daily num ber of truck loads.

Statistically assess the num ber of samp les required

to ob tain a 95 percent con fidence level on th e wastecomposition. The distribution of the individual

waste component can be assumed to be Gaussian.

However, there should n ever be less than 25 of each

type of waste.

Assess whether the seasonal variation necessitates

more than one round of samp ling (for example,

summer/winter or wet/dry).

Executing th e practical part of the waste composi-

tion sur vey requires additional careful planning. The

physical facilities must b e prepared to p rotect th e staffperforming the sorting and ensure that samples and

results remain representative. Sortin g is best carried

out in well-vented buildings with concrete floors to

ensure that n o waste is lost. The sorting station m ust be

furnished with sorting tables, a screen, easy-to-clean-

buckets or con tainers, and at least one scale. The logis-

tics are sum marized in Table 2.8.

Sort ing waste to a reasonable degree of accuracy

requires tha t sta ff have advanced t ra in ing. The

pickers must learn to recognize the different waste

categor ies especially different types of plastics.

They mu st empt y cans, jars and bags before placing

them in containers. To ensure consistency, the sam-pling and sorting process must be controlled and

supervised by the same person throughout the

waste survey. Furthermore, all procedures, includ-

ing laborator y analyses and meth ods of calculation,

m ust be described in d etail in a waste char acteriza-

tion m anual.

Sortin g categories shou ld be based o n t he am oun t of

the characteristic categories and their influence on the

calorific value. Table 2.9 presents some of the t ypical

characteristic categories. The recomm ended m inimu m

num ber of categories are presented together withopt ional sub divisions. Typical lower calorific values for

the ash an d water free sam ples (Hawf) are given for each

type of material. These values are approximate, and

laboratory measurements of H awf should to a certain

extent be applied to supplement and confirm or sub-

stitute literature values when calculating the overall

heat value of the waste.


Table 2.8 Logistics and Principles of Sampling and Analysis of Waste DataSampling The co llect ion veh icle from the represen tat ive co llect ion d ist r ict is in t ercep ted accord ing to the p lan.

Weigh ing The veh icle is weighed fu ll and la ter empty resu lt ing in the tot al weigh t .The waste vo lume is det ermined / est i-

mated and the average density calculated.

Subsampling Somet imes sor ting of fu ll truck loads is too t ime consuming. P repar ing a represen tat ive subsample (perhaps

100 kg) often makes it possible to sort waste from m ore tru cks and th ereby makes the result m ore significant.

However, preparing a representative subsample is not simp le, and a detailed procedure for this routine mu st

be prepared for example, accoun ting for drained- off water.

So rt in g T he wast e is u n lo ad ed on th e flo or of t he so rt in g b uild in g. It is t hen sp read in layer s ab ou t 0.1 m et er th ick o n

sorting tables covered by plastic sheets. The waste is manu ally sorted according to the p redetermined material

categories. The leftover on the table is screened (with a m esh size of about 12 m m) . The screen residues are

again sorted m anu ally, and t he rest is categorized as fines.

This procedure is followed un til the entire load or subsample including floo r sweepings has been divided

into the app ropr iate fractions.

Physical Analysis All fractions are weighed and the moisture content determined through drying after shredding at 105 C until

a constant weight is obtained (abo ut 2 hou rs). The mo isture content is determined on representative samples

of all fractions on th e day of collection.

Chemical Analysis The chemical analysis should be performed at a certified laboratory. The key parameters are ash content and

combu stible matter (loss of ignition at 550 C for th e dried samples) and N et Calorific Value for at least the

food and th e fines fractions. Samp les must be hom ogenized throu gh prop er repetitive mixing and grinding,

and at least th ree analyses shou ld be perform ed on each fraction to min imize analytical errors.

Data Processing The wet and dry weight waste composi tion are calcula ted together with the interval of confidence.


25/111

Ultim ately, the waste survey allows a calculation ofthe average lower calorific value for each t ype of waste.

The formula for determining the lower calorific

value ( H in f) for each type of waste is:

H in f= H awf * C/100 2445 * C (kJ/kg)

By weightin g these ind ividual H in f for each type of

waste with th e percentage wet weight (M), the overall

lower calorific value can be foun d by app lying th e fol-lowing formula.

H inf, overall = M1/100 * Hinf,1 + M2/100 * H inf,2 +. . . . +Mn/100 * H inf,n

Waste Load Design Calculation

The waste sur vey and forecast will establish th e expect-

ed am oun t and composition of waste generated dur ing

the lifetime of the facility (for example, a 20-year peri-

od). The actual volum e of waste arr iving at the incin-

eration plant will depend on the efficiency of the col-

lection system , together with negative and p ositive

incentives for supp lying the waste to the p lant. The

most negative incentive may be an increased gate fee

compared to fee of landfilling.

Before deciding on the p lants design capacity, it isrecomm ended to app ly a factor for collection efficien-

cy to th e theoretical am ou nts. This is especially impor -

tant for comm ercial and indu strial waste, which m ay

include a larger proport ion of materials suitable for

recovery and recycling.

Waste as Fuel 17

Table 2.9 Ash and Water Free Calorific Value (Hawf) for Selected Types of Waste

Component

Main category Subcategories Hawf(mandatory) (optional) (MJ/kg)

Food scraps and vegetables 1520

(to b e analyzed in each case)

Plastics Polyethylene (bottles, foil, etc.) 45PVC (bottles, etc.) 1525

Polystyrene (wrapping) 40

Polypropylene 45

Textiles 19

Rubber and leather 2025

Paper Dry 1619

Wet 1619

Cardboard Dry 1619

Wet 1619

Wood and straw 19

Other com bustible *

Metals 0

Glass 0

Bones 0Other non com bustible 0

Hazardous wastes *

Fines (


26/111

The waste load on the in cineration facility will con sist

of a combination of domestic, commercial, and indus-

tr ial waste.

The basic load will, however, be dom estic waste,

which can be assum ed to be supp lied almo st entirely to

the incineration plant.Separate collection of waste with a high en ergy con -

tent can theoretically increase th e calorific value of the

waste fuel. However, this method is likely to fail in th e

practical world du e to a lack of efficient waste separa-

tion at the source and the additional cost involved in

the collection system . Incineration of waste from cer-

tain areas (typically the m ore affluent on es) m ay, how-

ever, be feasible.

Mechanical sorting is another way to raise the

average calorific value before incineration. This istypically a step in th e produ ction of waste derived

fuel, and suitable techno logy is available, but it usu-

ally isnt used before mass burn ing because of addi-

tion al costs.



27/111

Key Issues

The success of an M SW in cineration plant depends as

much on the institutional framework as on the waste

and technology. There are four main institutional

framework areas to consider: the waste sector, th e orga-

nization and m anagement of the incineration plantitself, the energy sector, and the author ities responsible

for control and enforcement.

The institu tion al framework for the waste sector and

the waste management system must be sufficiently

developed to ensure supply of the design waste flow

and qu ality of waste for the life span o f the incineration

plant. The waste sector m ust further d esign and oper-

ate a controlled landfill for environmentally safe dis-

posal of the incineration residues.

An organizational set-up that can administer the

plant and support the waste incineration project sothat it becom es an integral part of the waste man-

agem ent system is crucial. There should be a high

degree of interaction between the different parts of

the waste management system and t he waste incin-

eration plant either th rough ownership or long-term

agreements.

Incineration is significantly more costly than

using landfills. The waste generatorsthat is, the

population and the comm ercial sectorm ust there-

fore be willing to pay the addition al cost, or else there

m ust be a subsidy schem e. Insofar as the operator /owner of the MSW incineration plant is supposed to

collect treatment charges, there mu st be ways to

enforce this.

When ownership is private, there may be institu-

tional borderline problems in th e delivery of a suffi-

cient quantity and quality of waste, the pattern and

price of sale of energy, or both . Waste flow mu st be con-

trolled, thu s ensuring that it is delivered to t he m ost

appropriate plant and, in particular, that indiscrimi-

nate du mpin g is avoided. Waste flow can be con tro lled

by a combination o f tariff policy (including cross-sub-

sidization via the t ippin g fee at the licensed facilities),

enacting and enforcing waste management legislation,

and a waste data an d recordkeeping system.Traditionally, the waste m anagem ent sector is

viewed as an un desirable place to work. In some

regions, th is has resulted in po orly man aged waste ser-

vices. Plus, it has been d ifficult to recruit and m aintain

qualified stafffor instance, in rapidly growing

economies where the public sector cannot match the

salaries of private companies.

In particular, operating and maintaining waste

incineration requires a highly skilled and effective

managementwhich means that new and skilled

m anagers may have to be attracted. Existing staff willhave to be train ed and capacity will have to be expand -

ed. Also, it should be decided whether to involve the

private sector in operation an d m aintenance. The nec-

essary skills and education resemble the human

resource deman ds in th e energy sector, for examp le,

management of power plants.

To ensure proper and environmentally safe opera-

tion, author ities responsible for control and enforce-

m ent mu st be on han d. These autho rities m ust be inde-

pendent of the owner and operator of the waste

incineration plant.In general,incineration plants are influenced by and

depend on num erous legal, institutional, and socio-

econom ic factors in th e environm ent. To assess fully

the appropr iateness of a proposed institution al fram e-

work, a compr ehensive stakeholder analysis must be

performed for both the existing and projected situa-

tions.

19

3 Institutional Framework


28/111

Key Criteria

A well-functioning solid waste manage-

m ent system, including a properly engi-

neered and controlled landfill,h as been pre-

sent for a num ber of years.

Solid waste collection and transportation

(dom estic, commercial, and indu strial) are

m anaged by a limited nu m ber of well-regu-

lated and controlled organizations.

There are signed and approved letters of

intent or agreements for waste supply and

energy sale.

Consum ers and pu blic author ities are able

and willing to pay for the increased cost ofwaste incineration.

Auth orities respon sible for cont rol, m oni-

toring, and enforcing operation are present.

The authorities responsible for control,

mon itoring, and enforcement are indepen-

dent of the ownership and operation of the

plant.

Skilled staff for plant oper ation are availableat affordable salaries. Otherwise, reliable

operation and/or maintenance contracts

are in place either in the form of operation

and service contracts or via BO/DBO/

BOOT/BOO schemes.

The waste management aut hor ity owns the

incineration plant.

Mun icipal guar antees cover any shor tfalls in

the plant econom y due to insufficient sup-ply or quality of waste.

Waste Sector

The waste sector in cludes public institution s and orga-

nization s as well as private comp anies involved in col-

lection, tran sportation, and final disposal of all types of

solid waste. Generally, collection of waste from hou se-

holds and shops in r esident ial areas is based on a p ub-

lic initiative. Large com m ercial centers, office com -

plexes, and industries are, however, often required to

arrange their own waste collection and disposal. Thus,there may be many operators involved in solid waste

collection and t ranspor tation.

A fully developed and controlled solid waste man-

agement system is a precondition for establishing an

MSW incineration plant. A functional management

system sho uld have been in placefor at least a few years

before implement ing the incineration plant.

A well-function ing solid waste man agement system

ensures that all domestic, comm ercial, and industrial

wastes are collected, tran sported, and disposed of in a

hygienic and environmentally safe manner at sanitarylandfills. Where such system s do not exist, the collec-

tion is much less efficient, and a significant par t of the

waste is likely to be disposed of throu gh un controlled

dumping.

If the waste management system is not fully con-

tro lled, increased incineration costs are likely to insti-

gate mo re illegal waste disposal activities. The u ltimate

effect may be that the supply to the plant becomes

insufficient in quantity or quality.

From waste generation to d isposal, various kinds of

more or less organized recycling activities take place.The comm ercial sector and the ind ustries emp loy their

own staff to salvage materials to sell and recycle.

Scavengers may be foun d at any stage of the han dling

system. They search dust bins and con tainers close to

the point of origin of the waste dump sites. Disturbing

the waste flow by introducing solid waste treatment

facilities may force the scavengers to shift their oper-

ation from th e end o f the waste chain toward the begin-

ningthus changing the waste composition believed

to be available.

The complexity of the waste man agement systemhas occasionally caused legal problems regarding the

ownership of the waste. The crucial question is: When

does waste change from private property to a public

nu isance or asset? If this is not clear from a legal poin t

of view, it is difficult to comm it or ensure the supply of

waste to the treatment facility. Thus, regulatory

changes may be necessary.



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Paym ent for services rendered is generally crucial in

waste management. Public health pro tection requires

waste to be collected and disposed of away from inh ab-

ited areas, bu t n ot all areas or sectors m ay be willing or

able to pay for such services. The on ly secure way of

recovering the costs is through mandatory servicecharges collected from th e waste generator spo ssibly

together with property taxes or service charges for

water an d electricity.

Private waste operators serving tr ade and indu stry

are likely to dispose of waste in th e cheapest po ssible

way, even u sing an illegal meth od such as indiscrim i-

nate dumping. Strict control and enforcement are

required to pr event such activities.

Energy Sector

Incineration plants consume and generate large

amou nts of energy and are therefore impor tant players

in the local energy marketespecially in relatively

small comm un ities. It is thus impo rtan t to establish

whether an incineration plant for solid waste can be

integrated in to th e legal and institutional framework of

the energy sector.

The energy sector is often heavily regulated.

Con cession to pro du ce and sell electricity is generally

granted only to a limited num ber of public or privateoperators. An incineration plant established by anoth -

er organization may therefore face opposition in

obtaining n ecessary app roval. Cooperation with exist-

ing energy producers or consumers can therefore be

useful.

Prices of energy paid by consumers m ay be subsi-

dized or taxed rather than based solely on p rodu ction

costs.Th e prices of energy from waste incineration m ay

therefore have to be fixed by the governmentwhich

brings up im por tant p olitical and socio-econom ic con-

siderations. A high price resulting in a redu ced gate feewill sub sidize th e waste sector, whereas a low p rice will

favor the energy consum ers.

It is most feasible when the energy can be sold to a

single consum er for its own use or resale. The con-

sumer may be a utility company with an existing dis-

tribution network for district heating or power or a

large steam-consuming industrial complex.

The pur pose of solid waste incineration plants is to

treat waste and h ence reduce the waste volum e for dis-

posal. The design and layout of an incineration plant

are based on continuous operation at 100 percent

load. In principle, the energy outpu t will be alm ost

constant 24 hou rs a day. The waste energy can th ere-fore be regarded as a supplement to other fossil fuel-

based en ergy sour ces that are o perated at a load corre-

sponding to the actual energy demand. Norm ally, the

energy produced from incineration p lants is regarded

as base load. Depending on th e price pattern, the price

of th e waste gener ated energy will reflect this base load

status.

To u se all the energy produced, incineration plants

should m ainly be established in large energy networ ks

where they can function as base load units with both

diurnal and seasonal variation.

Incineration Plant Organization and Management

Ownership and Operation

MSW incineration plant ownership and allocation of

operational responsibility is of great impor tance.

Different kinds of borderline problems may arise

depending on the m odel. These problems are related to

supp ly and q uality of waste, as well as sale and distrib-

ution of heat, or bothdepending on whether theplant b elongs within the waste sector, the energy sec-

tor, or to a private operator.

Incineration plants belonging to the solid waste

management organization responsible for waste col-

lection, transportation, treatment, and ultimate dis-

posal generally experience few problem s regarding th e

supply offuel or d isposal of residuals. The m ain insti-

tu tion al problems are related to th e selling and distr ib-

utin g energy.

Altern atively, the incinerat ion plant m ay be located

within th e energy sector and belong to the power sup-ply compan ies. Here, there are no p roblems with sell-

ing and distributing energy. However, there may be

problematic cultural differences between the energy

sector and the waste sector.

The energy sector is accustomed to a highly stan-

dardized fuel quality and is not used to variations in

quantity and quality of waste. Normally, energy pro-

Institutional Framework 21


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ducers modu late the operational pattern according to

the energy deman d. MSW incineration plants, howev-

er, have to follow the pattern of supply rather than

deman d. They m ust therefore accept variations in

quant ity and quality of the fuel and energy outp ut. An

energy sector-based incineration plant owner willtherefore try to exercise control over maximum and

min imu m waste supply and qu ality.

Privatization of incineration plants can include

combined ownership and operation o r operation on ly.

Fully privatized facilities may experience borderline

problems towards both the waste management and

energy sectors. Establishing the necessary agreemen ts

is complicated, and pro blem s m onitor ing and contr ol-

ling the waste supply and energy sale will develop.

The bord erline pro blems between th e sectors mu st

be solved through firm and irrevocable agreementsbefore plans are made to bu ild the plant. Oth erwise,t he

feasibility of th e plant is jeopardized.

Staff recruitment an d m aintenance m ay be crucial

when deciding on the plants ownership. In boom ing

econom ies, the governm ent often pays significantly

smaller salaries than th e private sector. In return , the

governm ent and other aut horities often provide pen-

sion schemes and greater job security than the private

sector.

This may make it difficult for the public sector to

attract enough qualified staff. Staff trained at theplants expense may leave for better p aying jobs. The

privately owned and operated facilities can better

retain staff, since they can pay comp etitive salaries and

incentives. Both private and pu blicly operated plants

mu st, however, expect to have a continuous hum an

resource development (HRD) program to maintain

staff for plant operation and maintenan ce.

The organizational set-up and financial manage-

ment system for the incineration plant can influence

plant u pkeep and m aintenance. Several special equip-

ment spares and components may be available onlyfrom abro ad. Because spendin g foreign currency can

be restricted or may require an extended approval

process, procurin g em ergency replacement p arts may

cause the plant to shut d own for long periods of time.

It is preferable for the incineration plant to be an

econom ic entity of its own, whether publicly or pr i-

vately owned and operated. This gives the plant m an-

ager the freedom to acquire local spares and mainte-

nan ce con tracts quickly.

Waste incineration is significantly mo re costly than

waste disposal in sanitar y land fills, even after incorp o-

rating the revenues from sale of energy. The addition-

al costs can seldom be collected as a gate fee alone,because the waste might b e taken an d disposed of in an

un controlled man ner. The budget deficiency mu st be

covered by general waste service charges,o th erwise col-

lected or compensated for through subsidies.

Waste m anagemen t charges should generally be col-

lected by an authority which holds sufficient legal

power to app ly reprisals when p aym ents are not mad e.

Establishing n ew entit ies solely to collect in cineration

fees is costly and m ust b e accom pan ied by an allocation

of enforcement power to collect overdue payments.

Tender Models for Waste Incineration Plants

Table 3.1 outlines the principal tender models and

ownership and m anagem ent m odels for waste inciner-

ation plants.

The tradition al tender m odel is the mu ltiple contr act

or single tur nkey contr act model. After com missionin g

the plant, the client typically the mun icipality, a group

of mu nicipalities or a public waste managem ent insti-

tution begins operating the plant.

These m odels ensure the most pu blic contr ol of ser-

vice level, plant perform ance, plant finance, and tariffsetting. However, the client m ust bear the fin ancial bur -

den of the investm ent and acquire the management

and technical skills for implementing and operating

the plant. A time-limited management and training

(H RD) contract (abou t 1 or 2 years) m ust be included

in the scope of supply.

If the multiple contract mod el is applied, the divi-

sion into lots mu st be lim ited and respect th e natur al

entities. The furnace and boiler, for instance, mu st be

in on e lot. However, un less the client has experienced

personnel with firm knowledge of procurement andwaste incinerat ion skills, it is stron gly advisable to

divide the lots into no more than two main supplies:

complete machinery and structural.

The operation contract has been applied where

municipalities wish to free resources from opera-

tion al duties or where it has been mo re econ om ical to

let an experienced private contractor operate and



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maintain th e plant. It is also applicable where the

client has established a plant accord ing to one of the

aforementioned models but wants a different con-

tractorfor examp le, a local companyto operate

the plant.

There are several variants for u sing private contr ac-tors in d esigning, financing, and operating incinera-

tion plants. In one comm on variant of privatization,

supervision and contr ol of private contractors is per-

formed by highly skilled clients (municipalities/

author ities). In particular, the client must have highly

skilled legal, contr actual, and finan cial specialists to set

up contracts for implementing,operating,owning,and

financing incineration p lants with pr ivate contractors.

Detailed and professional contracts must be estab-

lished to p rotect th e clients obligation to p rovide effi-

cient, affordable, and environmentally sustainablewaste management services to the community.

In general, the client loses financial and technical

maneuverability when entering into long-term service

contracts with private contractors, but on the other

hand, financial resources and staff are liberated for

other pu rposes. The client mu st also offer guarantees

on the supp ly of waste, sale of energy, and payments to

the contractor (put or pay contracts). The put or pay

contracts are the contractors insurance against

increased n et treatment cost if major preconditions

failfor example, m inimu m waste supp ly or calorificvalue of the waste. (For information on the conse-

quences when pr econd itions fail, see chapter 4par-

ticularly Figure 4.4.)

The client will also be asked to issue gu aran tees for

the servicing of the loans used by the contractor to

finance building the plant.

Deciding whether to cont ract out the establishm ent,

operation, financing, or ownership of incineration

plants to p rivate contractors should n ot be t aken light-ly. It is impor tant to weigh consciously the advantages

and constraints of all options against the local cond i-

tionsin particular, the clients creditworth iness and

resources in term s of capital and staff skills, as well as

the actual legal framework for pub licly m on itor ing and

controlling a private contractor.

Authorities

Authorities responsible for control, mon itoring, and

enforcement must be present to ensure proper plant

operation and compliance with the environmentalstandards against which the incineration plant was

approved and intended. These authorities mu st be

independent of the ownership and operation of the

plant.

About once a month, the plant management m ust

subm it repor ts on the average flue gas emission values,

amoun ts and composition of residues, flue gas reten-

tion times, and other operational parameters (for more

inform ation, see Part II). The report m ust clearly state

all exceeded limits and explain t hem .

Based on these reports, correspon dence with theplant management, and inspections, the authorities

mu st take proper action if the plant is not op erated in

an environm entally safe way.



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Key Issues

Waste incineration involves high investm ent costs with

a large share of foreign currency and h igh op erating

and m aintenance costs. Hence, the resulting net treat-

men t cost per m etric ton of waste incinerated is rather

high comp ared to the alternative (u sually, landfilling).Depending on the actual costs (which are sensitive

to the size of the plant) an d revenues from th e sale of

energy, the net treatment cost per m etric ton of waste

incinerated will normally range from US$25-$100 (in

1998) with an average of about US$50. Depending on

the quality (for example, num ber of membr ane layers

and leachate treatm ent) of the actual landfill site, the

net cost of land filling ranges from US$10-$40.

Thus, higher net treatm ent cost is a critical issue

when considering imp lem enting a waste incineration

plant. Financing can be done in term s of tipping fees, ageneral levy, public subsidies, and combinations there-

of. However, the ability and willingness to pay should

be considered tho roughly to avoid th e risk of un con-

trolled du mp ing or burn ing is latent.

Key Criteria

There is a stable plann ing environm ent ( 15

to 20 years) with relatively constant or p re-

dictable prices for consum ables, spare parts,

disposal of residues, and sale of energy.Furtherm ore, the capital costs (large share

of foreign currency) can be predicted.

Financing the net treatment cost must

ensure a waste stream as intended in the

overall waste management system.

Consequently, the waste incineration tipping

fee mu st be lower than (or at least, no greater

than) the fee at th e landfill. Willingness and

ability to pay must be addressed.

Foreign curr ency is available for p urch asing

critical spare p arts.

To b e econom ically feasible, the capacity of

the ind ividual incineration lines shou ld be

at least 240 t/d (10 t/h) . A plant should have

at least two ind ividual lines.

When surplus energy is to be used for dis-

trict heating, the incineration plant m ust be

located near an existing grid to avoid costly

new tran smission system s.

If a regular market for the sale of hot water(district heating or similar) or steam is pre-

sent, the plant should be based on the sale

of heat onlyboth in terms of technical

comp lexity and econ om ic feasibility. A cer-

tain extent of cooling to the environment

dur ing the warm season m ay be preferable

to costlier solutio ns.

Economics

The mass burning principle with a moving grate is

applied in the following economic analysis and esti-

m ate of the investm ent costs for th e machinery. This is

the most widespread and well-tested technology for

incinerating MSW. Furthermore, other technologies

cannot be recomm ended for incineration of norm al

MSW (see Part II of this Guide).

25

4 Incineration Plant Economics and Finance


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Investment Costs

The actual investment cost for a waste incineration p lant

depends on a wide range of factors, especially the size

(capacity) of the plantthe number of metric tons per

year or day and the correspond ing lower calorific value of

the waste. Low-capacity plants are relatively more expen-sive than high-capacity plants in term s of investment cost

per m etric ton of capacity.

The machinery (and hence, the investment costs)

depends on the type of energy production, ranging from

simple cooling of all excess heat (n o energy sale) to com-

bined heat and power production. Furthermore,the equip-

ment necessary for flue gas cleaning is to a great extent

determined by the desired or required emission quality

level,which consequent ly influences the investm ent costs.

The investm ent costs as a fun ction of the annu al (and

daily) capacity for a typical new waste incineration plantare estimated in Figure 4.1. A lower calorific value of the

waste of 9 MJ/kg (2150 kcal/kg) is assum ed as the design

basis. A higher calorific value will increase the actual

investm ent costs and vice versa.

Furthermore, the following preconditions corre-

sponding to a typical plant configuration in South and

Southeast Asia apply.

Number ofincineration lines.The minim um capacity of

each incineration line is 240 t/d (10 t/h ) and the m ax-

imum is 720 t/d (30 t/h) . There should be at least twoincineration linesso p lants should be at least approx-

imately 500 t/d. When calculating the necessary daily

capacity based on the an nual dimensionin g waste vol-

um e,an availability rate (num ber of operating hours a

year) of 7500 is presum ed. Furthermore, 5 percent

excess capacity is presumed to cover condition s such as

seasonal variations.

Energy production. The plant prod uces steam primari-

ly for electricity prod uction but if it also is involved in

combined heat and p ower pro duction or sale of elec-tricity and steam, excess heat is cooled away. Hence, the

plant is equipped with steam boilers, turbine u nits,and

condensing/cooling units.

The total investm ent cost can be reduced by approxi-

mately 30 percent if the plant is equipped for hot water

production only.

Flue gas cleaning. The plant is equipped with dry or

semidry scrubbers and a subsequent electrostatic pre-

cipitator or bag-house filter to exercise medium level

emission control.

The total investment cost can be reduced by approxi-mately 10 percent if the plant is equipped for compliance

with basic-level emission control.However, if the p lant has

to comply with advanced-level emission control, the total

investment cost must increase approximately 15 percent.

In Figure 4.1, the average investm ent cost per daily

capacity in metric tons is calculated according to the

aforementioned preconditions.

Norm ally, at least 50 percent of the investm ent costs for

the machinery part of the plant has to be covered by for-

eign currency.

Operating and Maintenance Costs

The operating and maintenance costs comprise:

Fixed operating costs

Cost of adm inistration and salaries

Variable operating costs

Cost of chemicals for the flue gas cleaning system

Cost of electricity (if the plant is equipped with a steam

tur bine and a turbin e/generator set, there will be a net

production of electricity)Cost of water and handling of waste water

Cost of residue disposal

Maintenance costs

Cost to maintain the machinery (such as spare parts)

Cost to maintain th e buildings


0

0 500 1000 1500 2000 2500

100 200 300 400 500 600 700 800

Figure 4.1 Investment Costs

0

50

100

150

200

250

300

350

0

301000US$/metricton/day

MillionUS$

Plant Capacity (metric tons/day)

Civil

Machinery

TotalInvestment/capacity

Plant Capacity (1000 metric tons of waste/year)

60

90

120

150

180

210


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The fixed operating costs depend heavily on the

num ber of employees, the percentage of skilled and

un skilled workers and engineers, and the local salary

level. The ann ual fixed operating costs for plants in

Sou th an d South east Asia are estimated at 2 percent of

Documents

World Bank - Waste Incineration