ENVIRONMENTAL

PERFORMANCE -

ARTICLES ON WASTE AND

RIVER MANAGEMENT

Sarawak Government/DANCED Sustainable Urban Development Project, Sarawak

Natural Resources and

Environment Board

NREB

State

Government

of Sarawak

Danish Cooperation for

Environment and Development

DANCED

ENVIRONMENTAL

PERFORMANCE -

ARTICLES ON WASTE AND RIVER MANAGEMENT

Edited by

CHONG TED TSIUNG

TANG HUNG HUONG

IB LARSEN

Danwaste

COWI Consulting Engineers

and Planners AS Danwaste Consult A/S

Environmental Performance - Article on Waste and River Management

1st Edition (1st Print)

August 2001-08-17 Copies: 400 The Authors and Danced Copenhagen

Quotations permitted with source credit

Printed by UM Colour Printing Company

Report No. SUD-02-38

ISBN 983-40546-4-5

TABLE OF CONTENTS

Foreword ............................................................................................................... i

Energy Utilisation and Environmental Aspects of Waste Incineration

in Denmark by Mr. Ib Larsen .............................................................................. 1

The Role of Local Authorities in Solid Waste Management in

Denmark: A Comparative Perspective by Mr. Ib Larsen ............................... 15

On Odour, Odour Measurement and Regulation by Mr. Arne Oxbol ........... 35

Danish Experiences in Collecting and Treating Organic Waste from

Big Kitchens by Mr. Soren Eriksen .................................................................. 45

The Challenge of Recycling Construction and Demolition Waste -

Focusing on the City of Kuching, Sarawak by Mr. Erik Lauritzen ................ 55

Closing the Rural-Urban Nutrient Cycle - New Trends in Organic and

Black Water Waste Management by Associate Professor Jakob Magid ........ 69

i

FOREWORD

The Danced funded Sustainable Urban Development Project, Sarawak (SUD) is

a 30-month project running from June 1999 to December 2001 and aiming to

develop and implement an overall Environmental Management System (EMS)

for the city of Kuching.

The project generally concerns the overall legal and institutional aspects of the

system development. But at same time the project aims to implement the system

for two areas of concern (AOC) selected: river water quality and solid waste

management.

The key initiatives within the two AOCs are elaboration of comprehensive

baseline studies that can serve as a firm basis for goal setting and selection of

measures required for achieving the goals.

During the elaboration of the baseline studies several specific issues related to

the AOCs have been highlighted for different reasons. Typically there has been

a need for going into more detail with issues that requires special attention in

relation to the present situation in Sarawak.

Dealing with these specific topics has often included technical presentations by

foreign specialists. This book constitutes a collection of such presentations,

which the project considers of relevance for discussions in a broader context.

The articles include presentations related to the two areas of concern selected for

the SUD project.

Several of the presentations were conducted as “High Tea Talks” organised by

the SUD Project.

The “High Tea Talks” presented in the book include:

"Closing the Rural-Urban Nutrient Cycle - New Trends in Organic and

Black Water Waste Management." This talk presents the international state

of development of new pipe-free ecological wastewater treatment concepts,

based on recycling of the organic material and then nutrients. The

presentation was conducted by Associate Professor Jakob Magid from the

Royal Veterinary and Agricultural University, Denmark;

"On Odour, Odour Measurement and Regulation." This talk presents the

concepts of odour measurements presently used in Europe and USA in

accordance with internationally recognised standards. The presentation was

conducted by Arne Oxbol from dk-TEKNIK Energy & Environment,

Denmark;

ii

"Danish Experiences in Collecting and Treating Organic Waste from Big

Kitchens." This talk presents the Danish experience in recycling of organic

waste from restaurants and food outlets for pig feed. The presentation was

conducted by Project Manager, Soren Eriksen from R98 Cleansing

Company, Denmark;

"The Challenge of Recycling Construction and Demolition Waste -

Focusing on the City of Kuching, Sarawak." This talk presents international

experiences on recycling of construction and demolition (C&D) waste. The

talk includes a discussion of the conditions required for introducing C&D

waste recycling in Sarawak. The presentation was conducted by the

Director, Erik Lauritzen from DEMEX Consulting Engineers A/S, Denmark.

The book further includes papers presented by the project at different project-

external occasions:

The article "The Role of Local Authorities in Solid Waste Management in

Denmark: A Comparative Perspective" describes the role of the local

authorities in waste management in Denmark, and compares the Danish

structure with the present situation in Sarawak. The article was prepared for

the Sarawak Local Authorities Conference Sibu, Sarawak July 2000;

The article "Energy Utilisation and Environmental Aspects of Waste

Incineration in Denmark" describes the environmental preconditions for

undertaking waste incineration as a major component of solid waste

management, and the environmental experiences on incineration obtained in

Denmark. The article was prepared for the Malaysian Chemical Congress 99

(MCC‟99), held in Kuching, Sarawak November 1999.

It is my sincere hope that the book could inspire and contribute substantially to

the sustainable environmental strategies and technologies in Sarawak.

CHONG TED TSIUNG

Acting Controller of Environmental Quality / Project Director of SUD Sarawak

1

ENERGY UTILISATION AND ENVIRONMENTAL ASPECTS OF

WASTE INCINERATION IN DENMARK

Ib Larsen

Chief Technical Advisor

Sustainable Urban Development Project

Natural Resources and Environment Board, Sarawak

INTRODUCTION

Denmark has along tradition for including waste incineration in waste

management strategies. The first incinerators for municipal waste were

established at the end of the 19th century, but the birth of modern waste

incineration can be dated to the beginning of the 30‟s when new Voelund rotary

kiln facilities were constructed in the capital region. Already at that time energy

utilisation played an essential role as the economic crisis in the 30‟s underlined

the importance of reducing fuel import. The first facility in Frederiksberg from

1931 supplied a hospital and other surrounding institutions with district heating.

The tremendous economic growth in the 60‟s caused a similar growth in waste

amounts and as a result the local authorities all over the country started to

establish incinerators, which mushroomed all over the country. In 1970 alone 49

incinerators were established. The main cause for establishing incinerators was

waste volume reduction and for hygienic aspects. At that time the energy saving

aspect was not considered, however, this was totally turned over from the mid-

1980‟s when the risk of global warming became evident.

WASTE INCINERATION AND THE GREENHOUSE EFFECT

From the mid 80‟s, waste incineration in Denmark became an integral part of

the official environmental policy, primarily because the greenhouse effect

generated a need to lower the methane formation associated with waste

depositing and due to a desire to utilise the energy content of the waste for

energy production, refer to Table 1.

2

Table 1

CO2 Contribution from Waste Incinerated at

AMAGERFORBRÆ NDING 1996 Compared to

CO2 Contribution by Depositing the Same Amount

WASTE INCINERATED 348,.000 t

CALORIFIC VALUE 2,500,000 GJ

CORRESPONDING TO 60,000 t Oil

TONNES OF CO2 equivalent

DEPOSITING

INCINERATION

CO2 Emission, waste disposal

site

1,560,000

CO2 Emission (incineration of

60,000 t of oil)

190,000

CO2 Emission, waste

incineration

360,000

TOTAL

1,750,000

360,000

Methane generated by waste depositing accounts for about 33% of the total

methane emission in Europe.

In 1990, a total ban on landfilling organic waste was introduced in Denmark.

Any organic waste whether being food waste, wood from construction works or

whatever – were banned at landfills. The clear intention with this initiative was

that all waste, that could be used as a fuel for energy production, and not be

recycled, should be used for energy production purposes. Secondly a tax was

introduced for waste that was not recycled. This tax was considerably higher for

waste landfilled (50 US$ per ton today) than for waste used for energy

production (40US$ per ton today).

3

However, the incineration strategy still remains secondary in waste

management. The primary strategy is being to recycle the largest volumes

possible of all waste fractions.

Be that as it may, this article is not intended as a discussion of the strategy of

recycling. Copenhagen‟s recycling strategy is described in Lit. 1 and Lit. 2.

The strategy is founded on the authority granted to the local authorities in

Denmark to require source separation of all fractions from all sources,

households as well as industries, institutions, construction works, etc. The local

authorities have also been sufficiently empowered to ensure that the fractions

are actually forwarded for recycling.

Figure 1 Treatment of Total Waste Volumes in Copenhagen Municipality

in Tonnes

Figure 1 shows the distribution on recycling, incineration and depositing of all

waste fractions from all waste sources in Copenhagen. As seen, the incineration

share remains unchanged. This is because large volumes of waste previously

deposited are not incinerated whereas large volumes of waste previously

incinerated are now recycled.

But the incorporation into an environmental strategy of waste incineration calls

for constant rationalisation and optimisation of the energy yielded by

0

200000

400000

600000

800000

1000000

1200000

1988 1994 1996 1999 2007

Recycling Incineration Deposit Special Treatment

15%

36%

49%

59%

34%

4% 3%

56%

39%

3%

2%

60%

33%

3% 4%

66%

28%

2%

4%

4

incineration, to ensure that the facilities are merely constructed as power plants

based on waste than waste incineration plants with energy utilisation.

Elements of this shift in Denmark are:

source separation of non-recyclable waste into combustible and non-

combustible waste with a view to increasing the calorific value of waste for

incineration and reducing slag volumes;

extension of public recycling (container) stations with separate containers

for combustible and non-combustible bulky waste, which cannot be

recycled;

extension of plants from heat production to power-heat production;

redesign of plants for higher calorific values;

optimisation of incineration processes; and

extension of the district heating network. The district heating network in the

Greater Capital Region now covers urbanised areas as far as 60 km from the

city centre.

These elements are described in Lit.2.

Energy utilisation is undergoing constant improvements through, e.g. improved

district heating utilisation in the summer months. Thus, we have boosted our

efforts to base cooling systems on district heating. Likewise, we are effecting a

basic design change of incinerators away from grate/rotary kiln incinerators to

pure grate kiln solutions. These plants are paving the way for additional energy

optimisation, but also carry risks of impaired slag quality and thus the quality of

residues from the energy production. The conflict between energy utilisation and

environmental aspects is the subject for the rest of this article.

Waste incineration can only be maintained as a part of an overall environmental

strategy, if the environmental impact of the incineration process and residues is

eliminated or minimised. Clearly, this is the dilemma of the incineration

process.

A range of substances fall under the heading “what goes in, must come out”.

The incineration process cannot remove them, only change their appearance.

The incineration process may actually generate other hazardous substances.

Thus, incineration presupposes that authority, management and all involved

parties focus completely on minimising the impact of the process.

5

ENVIRONMENTAL PROBLEMS OF WASTE INCINERATION

Basically, the environmental load of an incineration plant depends on the

substances and materials put into the incineration process. Thus, the most

thorough way of removing environmental problems lies in controlling the input

to incineration plants. Source separation is a crucial precondition. To the extent

substances are introduced into the incineration plants, process optimising

becomes essential. For emissions, which cannot be removed by process

optimising the cleaning measures, become crucial. Even after a cleaning

process, the substances will still exist in the residues, thus making residue

handling essential.

Below, I will review the above aspects for chlorine compounds and heavy

metals, two of the substance groups significant to today‟s incineration quality.

My discussion of the related problems will be based on experience from the two

incineration plants owned jointly by the City of Copenhagen and the

surrounding local authorities: I/S Amagerforbrænding and I/S Vestforbrænding.

In 1996, both plants incinerated about 300,000 tonnes of waste in four 12 t/h

lines. Since then, another 26 t/h line has been added to the I/S Vestforbrænding,

and the lines at I/S Amagerforbrænding are currently being rebuilt to 15 t/h

each.

CHLORINE COMPOUNDS AND INCINERATION

Chlorine is a major contributor to pollution from waste incineration.

Hydrochloric acid and dioxins are the major contaminants but for the

incineration process itself chlorine is a problem. When temperature in the

facility exceeds 300oC, chlorine becomes very aggressive. This limits the

possibilities of superheating and subsequently reduces energy production

potential.

Keeping organic chlorine compounds out of the incineration process

About 50% of the total input of chlorine compounds to the Copenhagen

incineration plants stem from PVC. This means that avoiding PVC in the waste

may substantially reduce problems. Consequently, source separation regulations

in Copenhagen also entail source sorting of PVC from industrial and

building/demolition waste. For citizens, separate containers for combustible

plastics and PVC plastics individually have been set up at the regional recycling

centres.

6

However, it is difficult for citizens and for some industries to distinguish

between PVC and other plastics. Thus, the problem will only be resolved

completely, when PVC is phased out. In Denmark, a voluntary agreement was

set up between the Ministry of Environment and Energy and the plastics

industry to phase out the use of PVC in a wide range of applications.

Process optimisation and flue-gas cleaning

One of the main problems of adding organic chlorine for incineration is the risk

of dioxin and furan formation. Process optimisation would go a long way in

reducing the formation of the substances. Some of the methods appear from

Table 2.

However, our knowledge of the formation and decomposition of substances in

the process is today insufficient to ensure that process optimisation alone would

solve the problem.

Table 2

PROCESS OPTIMISATION PARAMETERS

- Limit of waste loads to design

- Continuos operation

- Prolonged operation periods

- Prolonged retention times

- Supportive burners

- Preheating of combustion air

- Fast flue gas cooling

Irrespective of process optimisation, analyses at our facilities indicate that the

emission of dioxin from flue gases would still – without extraordinary cleaning

measures – register at about 25-75 times over the suggested EU threshold value

of 0.1 mg per Nm3.

Thus, incineration plants in Denmark become a possible source for 50% of the

total dioxin and furan emission in Denmark.

At the Copenhagen incineration plants, these problems are solved by blowing

activated carbon into the flue gases. However, this process produces about 50

tonnes of very hazardous residues every year from the two plants.

7

In principle, the residual product can be re-introduced into the incineration

process to breakdown the dioxin. However, in the semidry process activated

carbon also catches polluting mercury, thus solving another environmental

problem. Unfortunately, this means that the residual product has to be deposited.

In the wet process mercury is caught in the scrubber before adding activated

carbon.

The chlorine content also produces hydrochloric acid, thus causing acidification.

Establishing flue gas cleaning may solve this problem. In Copenhagen,

requirements to flue gases on the new incineration lines are significantly tougher

than the proposed EU threshold values, refer to Table 3.

However, flue gas cleaning creates new waste volumes depending on the

cleaning method selected, refer to Table 4.

Due to the lime added, the semi-dry method used at the Amagerforbrænding

generates waste volumes corresponding to 5% of the total added waste volumes.

The wet method used at the Vestforbrænding generates less than half as much.

On the other hand, 1,400 tonnes of chlorides are discharged as a 1% solution in

the waste water every year. In many fresh-water areas this could cause

problems, if so, an additional evaporation process must be established to extract

the chlorine.

The wet method also produces plaster from the SO4 elimination. However, today

this is all earmarked for recycling.

Another problem relates to the amount of consumed water, refer to Table 5.

Copenhagen tries to solve the problem by having the I/S Vestforbrænding utilise

secondary water resources from preventive drillings at contaminated industrial

sites. I/S Amagerforbrænding has set up plans to employ the same method.

Seawater is also used at Amagerforbrænding.

The slags may contain organic compounds as a consequence of incomplete

incineration. EU has proposed a maximum content of 3% of TOC (total organic

carbon). Today, suppliers to Copenhagen must meet a maximum of 2% of TOC.

8

Table 3 Threshold Values for New Line at Vestforbrænding : Emission

Standard Flue Gas Cleaning

Emission standards (24

hours average at 11%

02 fluegas)

Parameter

Unit

Denmark

Expected

EU

Standard

Guarantee

values new

line VF:

Average

emissions

VF ‟93 +

„94

Particles Mg/Nm3 40 10 5 Approx. 5

CO Mg/Nm3 100 50 25 Approx. 10

HCl Mg/Nm3 50 10 5 5

HF Mg/Nm3 2 1 0.5 0.2

SO2 Mg/Nm3 300 50 25 200

NOX Mg/Nm3 None 200 150 350

NH3 Mg/Nm3 None 10 5 -

TOC Mg/Nm3 20 10 5 <5

Dioxins +

Furans

Mg/Nm3 None 0.1 0.1 -

Hg Mg/Nm3 * 0.05 0.05 0.02

Cd + TI Mg/Nm3 * 0.05 0.05 <0.01**

Sum af Sb,

As Pb, Cr,

Co

Mg/Nm3 * 0.5 0.5 <0.8*

* Danish values for Hg, Cd, TI, Sb, As, Pb, Cr, Cu, Mn are added differently

than expected EEC values

Table 4

1996

RESIDUES FROM FLUE GAS CLEANING

Amounts of residues Residues in % of waste

amounts incinerated

Amagerforbrænding

Semi-dry process

14,000 t 5%

Vestforbrænding

Wet process

5,800 t 2%

9

Table 5 Water Consumption

1996

WATER USED FOR FLUE GAS CLEANING

Amagerforbrænding

80,000 m3

Vestforbrænding

220,000 m3

HEAVY METALS

Heavy metals constitute an overall problem in waste incineration. The

substances do not disappear, so, irrespective of the cleansing method selected,

measures must be based on the fact that heavy metals remain in the cycle.

Keeping heavy metals out of the incineration process

To avoid heavy metals in the incineration process is a hopeless task. To some

extent, heavy metals exist in every type of waste fed into the incineration plant.

But avoidance of especially hazardous fractions is an essential precondition for a

secure waste incineration process.

Copenhagen currently focuses on pressure-creosoted timber, auto shredder

waste (car fluff) and electronics waste. For instance, analyses of heavy metal

loads at incineration of pressure-creosoted timber show extremely high

concentration in both flue gases and slags, refer to Table 6.

10

Table 6 Heavy Metals from Pressure Creosoted Timber

HEAVY METALS IN RESIDUES

FROM INCINERATION OF

PRESSURE-CREOSOTED TIMBER

Flue Gas

Mg/N m3 CU

CR AS

Before

Electrofilter

10

0.2 600

After

Electrofilter

5

0.2 300

Slags

Mg/m3 CU

CR AS

100,000 150,000 35,000

Thus, pressure-creosoted timber must not enter into the incineration process.

Copenhagen has imposed a mandatory scheme for depositing pressure-creosoted

timber. The national treatment plant for hazardous waste, Kommunekemi at

Nyborg, now tests gasification of the timber in a separate gasification plant.

However, the problem arises that waste producer and waste managers often find

it difficult to determine whether timber is pressure-creosoted. Often, old

pressure-creosoted timber stemming from demolition is nearly impossible to

distinguish from non-pressure-creosoted timber.

Car fluff waste used to be attractive to incineration plants because of its high

calorific value. However, calculations at the I/S Vestforbrænding prove that flue

gas and slag contents of heavy metals can be increased by more than 50% at

simultaneous combustion of small volumes of car fluff, refer to Table 7. Today,

this type of waste must also be deposited. Gasification test is also made for car

fluff waste at Kommunekemi.

11

Table 7

POSSIBLE INCREASE IN HEAVY METAL CONTENT IN EMISSION

FROM CO-INCINERATION OF 400 t/mth OF CAR FLUFF AT THE

VESTFORBRÆ NDING

Slags

Flue Gas

(Efter Rensning)

Cd

Pb

CU

Hg

40%

25%

60%

30%

40%

25%

60%

15%

Electronics waste can no longer be incinerated. In Copenhagen, electronics

waste must be source sorted, destined for disassembly.

Flue gas cleaning and residual product handling

Most heavy metals are retained in the flue gas cleaning plant or retrieved in the

slags. From the dry and semi-dry process the heavy metals are detained in the

particle filters. From the wet process the heavy metals are precipitated as

hydroxides, when neutralising the washing water from the flue gas cleaning by

adding lime. Mercury is either retrieved from flue gas by adding activated

carbon as in the dry and semi-dry process or precipitated in the scrubber by

adding H2S and Na2S, as in the wet process.

This, however, does not solve the problems. Experience from Copenhagen

shows that flue-gas treatment products are not sufficiently stable to retain heavy

metals. Problems have proven especially severe for Pb. The high pH caused by

the lime added is the main reason.

As a consequence, the Copenhagen waste incineration plants have launched test

projects with a view to stabilising heavy metals in the residues and extracting

the salts, refer to Table 8. Preliminary results indicate that the retention of Pb

may exceed 99%, but, on the other hand, the existing test plants have had a

negative effect on Cr and Hg, problems, which now need to be solved.

12

Table 8

PROJECTS FOR FLUE GAS CLEANING PRODUCT STABILISATION

FERROX-PROCESS

PROSPHATE / CO2 PROCESS

Both methods are based on washing the slags combined with simultaneous

oxidation or stabilisation.

Slag volumes account for 5-10% of waste volumes, in weight for about 20%.

Denmark attached significant importance to recycle slags in building and

construction works. Today, the vast majority of slags are sold for recycling.

A precondition for responsible recycling is, however, a limitation of the heavy-

metal volume in the slags. Denmark has set up threshold values for the total

content of heavy metals in slags a precondition for recycling. The total volume

can only be controlled through waste inputs. However, slag pollution will also

depend heavily on the leachability of the heavy metals. Technology

development in waste incineration does not focus much on these problems.

Thus, no general EU values apply for slag quality. This means that plant

suppliers are tempted to focus on optimisation in relation to flue gases where

threshold values become still more restrictive.

This is why Copenhagen has set up severely restrictive requirements to plant

suppliers in terms of leachability of heavy metals from slags, refer to Table 9.

To date, Copenhagen has solved this problem by using combined grate/rotary

kiln solutions, which excellent for melting heavy metals into the slags.

13

Table 9 Guarantee Values for Slags, New Line at I/S Vestforbrænding

Total Content

Leaching

PH < 8,0 – 11,5

Clorid < 4000 mg/kg < 2500 mg/kg

Sulfat < 20000 mg/kg < 6000 mg/kg

AS < 20 mg/kg < 0.1 mg/kg

Cd < 10 mg/kg < 0.05 mg/kg

Cr(tot) < 1000 mg/kg < 0.5 mg/kg

Cu < 7000 mg/kg < 0.5 mg/kg

Hg < 0.5 mg/kg < 0.01 mg/kg

Ni < 500 mg/kg < 0.2 mg/kg

Pb < 3000 mg/kg < 0.2 mg/kg

Zn < 5000 mg/kg < 0.5 mg/kg

But requirements to energy optimisation have led to a focus on pure grate

solutions. This is one reason why we have had to confront plant suppliers with

the tougher requirements to slags. In the new lines, the fulfilment of the new

requirements has given rise to both completely new grate designs and changed

sub-processes, including prolonged retention time in the kilns.

CONCLUDING REMARKS

The incineration of the part of combustible waste, which cannot be reused, is an

extremely significant aspect of efforts to curb the greenhouse effects.

It is, however, a difficult path to tread. Copenhagen has not been afraid to do so.

But it must be emphasised that this is because we have for many years focused

on waste and on high-quality waste treatment. As this article has revealed, there

are many pitfalls in the complicated process of waste incineration. A

precondition for success is that all stakeholders wholeheartedly desire a high

environmental standard. And the population must trust both authorities and

waste management to strive unconditionally for an optimum process.

In Copenhagen, there is an overall confidence in the public on validity of the

information provided by authorities and waste management on process

parameters and emissions. If this confidence were to start cracking, we would

find it difficult to maintain waste incineration in Denmark as an aspect of our

environmental strategy.

14

Literature

Lit. 1: Ib Larsen

»Common framework for the Setting-Up of Waste Management«

Paper for EU- Forum »Waste Management Plan« Brussels, 1994

Agency of Environmental Protection, City of Copenhagen, 1994

Lit. 2: Ib Larsen

»Coherency and Sustainability in Waste Management in Copenhagen«

Paper for the ISWA-Conference, Wellington 1997

Agency of Environmental Protection, City of Copenhagen, 1997

15

THE ROLE OF LOCAL AUTHORITIES IN SOLID WASTE

MANGEMENT IN DENMARK: A COMPARATIVE PERSPECTIVE

Ib Larsen

Chief Technical Advisor

Sustainable Urban Development Project

Natural Resources and Environment Board, Sarawak

SOLID WASTE MANAGEMENT - AN OLD MUNICIPAL TASK

By tradition solid waste management has been a task for the municipalities.

Waste management has been looked at as a part of municipal supply functions,

just as e.g. water supply, which the municipalities had to ensure as a basis for

development.

There were two main tasks:

- establishment of facilities for disposal of waste; and

- collection of household waste.

In Denmark the municipalities for many years have been obliged to establish

collection systems for household waste from cities with more than 2.000

households.

Commercial and industrial waste was seen as so-called »free« waste. The

companies were not obliged to use the public schemes. In many cases though

they did use collection schemes and the public disposal sites. But they could

also arrange their own transportation and disposal. The only regulation was that

the treatment facility had to be approved by the regional authorities.

The municipalities typically solved their problems individually, each

municipality having one or more landfills (Figure 1). The incinerators

established also typically only covered one municipality.

NEW PROBLEMS IN SOLID WASTE MANAGEMENT

The dimension of the task was growing tremendously from the beginning of the

sixties for two reasons. Firstly the waste volume increased quickly. Secondly

the adverse environmental impact was growing as a result of the use of new

chemicals and materials in the society.

16

These developments meant severe growth in the costs and in the complexity of

waste management.

Volume reduction

The increase in waste volumes had to be met with more advanced treatment.

First of all volume reduction. Volume reduction can be achieved by incineration,

which reduces the volumes till 7 to 8%. In Denmark this has by far been the

most used strategy.

Composting is another way of reaching volume reduction. Composting reduces

the waste volume to 20 to 25% and if the compost is usable as fertiliser or

material for soil improvement, the volume for disposal will be reduced till the

sorting rest. But for most of the period in focus the latter has not been the

situation for unsorted-composted wastes. The growth and use of chemicals in

the 60‟es contaminated the waste to a degree where you could not distribute the

compost produced to the soil.

Environmental protection

At the same time the growing environmental impact as a consequence of the

more hazardous character of the waste also called for more advanced waste

treatment.

The percolation from the landfills resulted in requirements for more advanced

lining, drainage, monitoring and possibilities for repairing. For incineration

facilities the problems were primarily connected to the air pollution. Heavy

metals, acids and dioxins became a great problem. The solution to this was the

fluegas-cleansing, which made the incineration process more complicated and

first of all more expensive. Also the treatment of the residues from incineration

became more complicated. This goes for both the slags and the product from

fluegas-cleansing.

17

Figure 1 Organised Municipal Landfills in Denmark 1970

18

Category Recycling

%

Incineration

%

Composting

%

Sanitary

landfill

%

Household

10 70 2 18

Bulk & Garden

0a 34 0a 66

Commerce &

Industry

26 28 0 46

Construction

7 2 0 91

Energy

production

67 0 0 33

Sewage sludge

30b 35 0 35

a Amount unknown b Application to land

Figure 2 Waste Handling in Denmark in 1985

MUNICIPAL SOLID WASTE MANAGEMENT FACING THE NEW

PROBLEMS

The rising cost and complexity in waste management made it more and more

critical to maintain the municipal structure in waste management. Typically a

landfill or an incinerator to be cost/effective should have a catchment area that

was bigger than a typical municipality. To address these problems the

municipalities voluntary established inter-municipal partnerships, where a

number of municipalities together formed a waste management organisation. In

Figure 3 the actual development of inter-municipal partnerships in the waste

management field in Denmark is illustrated. The size of the partnerships were

typically based on cost/effectiveness, see Figures 4 and 5.

Figures 6 and 7 shows the resulting development in the number of landfills and

incinerators in Denmark.

19

Figure 3 Inter-municipal Partnerships in Denmark

20

Figure 4 Cost of Waste Treatment Compared to Size of Facility

Figure 5 Cost of Waste Transportation Compared to Distanced from

Facility

21

1960 1970 1978 1986 1994

No. of facilities 2 49 57 39 37

Average size t/year 9,000 32,000 56,000

Figure 6 Number of Incinerators in Denmark

1970 1978 1986 1994

No. of facilities 1200 500 82 62

Figure 7 Numbers of landfills in Denmark

NEW AGENDAS IN SOLID WASTE MANAGEMENT

- WASTE MANAGEMENT BECOMES POLITICAL

But all the mentioned problems were still primarily concentrated on the only

task: to GET RID OF the waste. Other problems arose and changed the

development in waste management dramatically. Three elements in this process

must be put into focus:

Firstly the growing awareness of saving resources made recycling an important

task. Recycling both reduces the volume of wastes for disposals and saves

resources.

Secondly energy savings became of great importance. In the middle of the

seventies the growing prices of fossil fuels created a new interest in using other

fuels as e.g. waste for energy production. And from the middle of the eighties

the awareness of the global warming and the problems in CO2 production, made

it more and more important to keep the fossil fuels under earth where they

belongs.

And thirdly it became more and more important to get rid of the hazardous

waste before it entered the waste treatment system.

These three items created a shift in waste management from a technical problem

handled by the technicians and operation staffs to a political question, where the

politicians on all levels took actively part in the discussions and choices of

solutions.

22

Recycling of household waste

The introduction of recycling as a central focus can be divided into two phases.

In phase number one, which was running from the middle of the seventies until

the middle of the eighties, recycling was a question of reducing the growing

costs of raw materials that was a consequence of the oil crisis from the middle of

the seventies. This meant that the material in focus was first of all the well-

known industrial raw materials, e.g. papers, cardboard, glass and metals.

In this period the municipalities started to establish recycling centres, where the

citizen could deliver all types of pre-sorted waste. Typically a recycling centre

would accommodate containers for 12-18 different waste fractions. Containers

for paper, glass and cardboard were placed in the neighbourhood. And some

municipalities started to collect the waste from the household pre-sorted.

Sometimes the organic waste was collected separately, sometimes the “dry

fraction” were collected separately for central sorting and sometimes the dry

fraction was even collected pre-sorted in its components (paper, glass, etc.).

The introduction of the recycling scheme was followed by establishing a joint

institute between the municipalities of Denmark and the recyclers – Gendan,

with the only purpose of raising public awareness on recycling. The institute had

to conduct all kinds of awareness campaigns for the next 15 years, before the

complete success was achieved.

But from the middle of the eighties the problem with the environmental impact

from waste treatment gave a stronger focus on the materials which was

important to get out of the normal waste streams. This can be characterised as

phase number two.

A detailed description of this development is given in Lit. 1.

One important fraction was the organic waste. When the energy production

became more and more important for incineration, organic waste is no longer

wanted, in the incinerator as it has too low combustion value due to the moisture

content. At the same time the organic waste is not wanted on the landfill, as it

creates huge amounts of the strong greenhouse gas methane. On the other hand

organic waste is easy to recycle as fertiliser or soil improvement materials.

But as mentioned earlier the recycling of organic wastes is seriously depending

on reducing the content of heavy metals and other toxic substances in the

wastes.

23

The prerequisite for reintroduction of composting therefore was pre-sorting of

waste at the source. Experiments with central and mechanical sorting plants had

made it obvious that the recycling of waste under all circumstances would

demand pre-sorting. So the municipalities typically introduced pre-sorting of

organic wastes. This gave recycling of organic wastes a second chance.

A more detailed description of this development is given in Lit.2.

The development of organic waste recycling in Denmark, at the same time

continued in the direction of fermentation and biogas production, so not only the

organic materials are recycled for fertilisation but the energy is also utilised as

biogas. In Denmark, you see two development lines: Specialised facilities for

fermentation of industrial and household organic city waste and combined

facilities for organic city waste and agriculture manure.

The second fraction that became important was chemicals and other hazardous

wastes. A strong focus was put on materials containing heavy metals, different

solvents and photographic liquids etc.

Pre-sorting of hazardous waste then became of very great importance. In

Denmark special schemes for separate handling, transportation and treatment of

the hazardous waste was established already since the beginning of the

seventies. All municipalities in Denmark together formed one inter-municipal

partnership for treatment of hazardous waste from all municipalities. The

partnership established a common treatment facility and 18 receiving station

distributed all over the country. But from the late eighties, the municipalities set

up supplementing schemes for specific fractions like electronic equipment for

dismantling, refrigerators for collecting CFCs, lighting tubes and dental waste

for recycling mercury etc.

But for all the fractions recycled in the second phase: organic, equipment, etc.

there was no existing market for products.

So the municipalities had to enter into recycling by themselves. The

municipalities had to establish compost and biogas facilities, facilities for

dismantling of equipment and for recycling of heavy metals, CFCs etc.

Sometimes the municipalities did this individually, sometimes in inter-municipal

partnerships.

In the beginning developing new technologies is a risky trial and error process,

so the state government set up funding for supporting new municipal initiatives

on developing and implementing new technologies.

24

As the market for the products had to be developed the products often had to be

sold with a loss– but this was looked at as a part of waste management costs,

and was financed through the waste fees.

Also recycling of halogenated wastes became important. First of all chlorinated

materials, which was the most important source of acidification and dioxin

production in the waste treatment. Especially important are the PVCs, which

today is the greatest source of chlorine in the waste stream.

But recycling of PVC is very different of technical reason. Therefore this

problem could not be solved by the municipalities. Instead state government has

negotiated an agreement with the Plastic Industry on phasing out the use of PVC

for a number of products in Denmark.

Recycling of industrial wastes

To establish a coherent waste management system it is very important that the

industrial and commercial waste becomes integrated into waste management.

For industrial waste central sorting have typically historically been the solution.

This is not surprising, as typically in most countries, the municipalities have no

authority to demand the companies to pre-sort their waste and handle the pre-

sorted fractions in accordance with the decisions of the municipalities.

Table 1 New Trends in the Waste Sorting in Denmark

Starting year for new trends in commercial and industrial waste

sorting in Denmark

1981

Mechanical sorting plants

FIRST: Odense

1986 Manual sorting plants

FIRST: Frederikssund

Roskilde

1990 Pre-sorting at producer

MANY CITIES

25

As shown in Table 1, the trend in Denmark, from the beginning of the eighties,

was mechanical sorting plants. From the mid-eighties the experiences from the

mechanical sorting plants told us to reduce the ambitions and use manual sorting

plants, so the employees only sort the absolutely clean materials. The central

sorting facilities never managed to produce sufficient clean fractions. But also

this gives problems. Not the least in the form of problems with occupational

health from microspores or other allergy causing materials.

But in 1989, the municipalities in Denmark finally got the authority to issue

regulations demanding industries to pre-sort their wastes and handle the

fractions in accordance with the regulations of the municipality. From that time

source sorting of industrial waste was the only solution in Denmark.

MUNICIPAL WASTE PLANNING

With all the new environmental issues and regulations introduced, systematic

waste planning and goal setting become vital.

In 1982, the Danish government introduced an amendment to the Act on

environmental protection which imposed on municipalities the working out of a

proper mapping of waste flows and a specific waste management plan. The aim

was to increase recycling. An analysis of waste volumes and fractions would

make it possible to evaluate which waste fractions and which sources of waste

the efforts should be directed at.

The planning process dealt with all kinds of waste from all kinds of sources.

Thus plans also had to be made for the treatment of commercial and industrial

waste.

The major problem in this connection was the fact that our knowledge of the

volumes and the constitution of commercial and industrial waste was very

limited. One of the primary aims of the initial mapping stage of the planning

process was therefore to gain a more precise idea of the volumes of commercial

and industrial waste, its constitution and sources. This has been of great

importance to the subsequent implementation of schemes for commercial and

industrial waste. These schemes will be discussed below.

The national act on waste planning just laid down the framework for municipal

planning. The regulation stated that the municipal plans should secure at least

50% recycling of the wastes. But which materials was recycled and how the

recycling was reached, was up to the municipalities to decide. This gave great

possibilities for different solutions in different areas of the country with different

composition of industries, tourism e.g.

26

The municipal plans then set the goals for waste management, for the type of

treatment of individual fractions, and for the individual types of waste

producers. The plans also describe the means to reach the goals: Regulations for

the different types of sources, for inspection, monitoring and enforcement and

for facilities and schemes to be established.

From now on the municipal waste departments became important elements in all

municipal administrations in Denmark.

All costs - including the costs for municipal planning and administration are

paid by the waste produces through the waste fees.

MUNICIPAL SOLD WASTE MANGEMENT SYSTEMS

Municipal schemes for collection and treatment of waste can be arranged in

different ways.

The treatment system as well as the collection and transportation system can be

arranged from fully public schemes over different intermediates till fully private

schemes.

Public system

In Denmark, treatment facilities like incineration plants and landfills are public.

As mentioned earlier they are typically established as inter-municipal

partnership to get sufficient catchment areas. For landfills the Environmental

Protection Act state, that they have to be public owned, due to the great

environmental risks involved and the difficulties for carrying out adequate

inspection due to the current coverage of waste deposited. For hazardous wastes

all municipalities in Denmark have formed one public company Kommunekemi

to get sufficient catchment area.

Different forms of recycling are also public. This goes especially for recycling

of fractions where there are no private markets like organic waste.

Transportation of household waste is in many cities operated by municipal

companies.

27

Contracting

Contracting to a private company is another used method. It is often used for

collection of household waste.

In nearly all Danish municipalities where the collection of household waste is

not operated by the municipality it is given to a private company on a contract

base.

It is important to emphasise, that contracting in no sense removes the municipal

responsibility for planning, for setting goals, for achieving them and for

obtaining a high level of quality and service towards the citizens in waste

collection.

Contracting in Denmark, therefore, presupposes has the municipality has the

ability to act as a strong counterpart to the company, when making the contract,

and when carrying out the daily follow-up on the performance of the contractor.

Political goal setting on increasing waste sorting and recycling might easily

contradict with the rights of the contractor, if not carefully dealt with in the

contract. Some municipalities in Denmark solve this problem by issuing short-

term contracts running 2- max 4 years. To regain the contract the contractor has

to achieve the new goals set. In other municipalities (e.g. Copenhagen) the

contract is long-term, but it carefully describes the duty of the contractor to

achieve the goals set by the municipality during the contract period. The

collection fees are then endorsed yearly by the City Council following

negotiations with the company.

Also the quality and service towards the citizens has to be carefully defined in

the contract. Table 2 illustrates service goals to achieve in a one-year period for

Copenhagen Waste Contractor - R 98.

28

Table 2 R98 – Service Quality Goals for 1999

80% of household customers have to be satisfied or very content with the

service offered.

90% of business customers have to be satisfied or very content with the

service offered.

10% reduction of the amount of complaints from the customers by

incorrect or default of emptying.

90% of the collection of paper has to take place on the planned collection

day.

90% of the collection of garden waste has to take place on the planned

collection day.

80% of the collection of bulky waste from blocks of flats has to take place

on the planned collection day.

90% of the collection of bulky waste from neighbourhoods with terraced

or detached houses has to take place on the planned collection day.

95% of the scheduled arrival times have to be kept.

90% of glass containers emptied have to have a degree of filling of at least

25%.

All containers used for refuse, garden waste, and bulky waste have to be

checked for correct size and frequency of emptying.

60% of all the containers for domestic waste have to be checked for

correct size and frequency of emptying.

Based on the evaluation of satisfaction, possible improvements must be

identified.

Concerning the fault of emptying containers, 80% of the verbal complaints

must be dealt with by the end of the same working day.

Reduce the 3 most frequent reasons for complaints from the customers by

5%.

Authorisation and permits

On all areas of collection and treatment where public operation or contracting is

not used it is of importance to ensure a permit or authorisation system for all

parties that operates in the system.

In the City of Copenhagen, collection and treatment of commercial and

industrial waste is based on a permit system. All transporters and all recyclers

and other treatment plants cannot go into business before they have got a permit

to collect or treat waste from the City. To get this permit they will have to sign a

statement that the materials are sorted and treated as stated. For getting a permit

you have to guarantee that recycables are transported for recycling and

29

combustibles are transported for incineration and non-combustibles are

transported for depositing to sanitary landfills.

Also the treatment plants need a receiving permit. No treatment plants are

allowed to receive waste from the City of Copenhagen without a receiving

permit from the City.

An important aspect of the system is the registration. The transporters and the

treatment plants have to registrar all transported and treated wastes from the

individual sources. All this information is delivered to the municipality in a

computerised form, which means that the City always has an overview of the

stream of wastes from each individual source.

If a company does not fulfil the conditions in its permit, it will lose it and go out

of business. An overview of the Copenhagen regulation of industrial waste is

given in Lit. 3.

WASTE MANAGEMENT TASKS AND DUTIES IN DENMARK

The distribution of tasks and duties in Denmark can be summarised as follows:

The State Government generally establishes the framework for waste

management, describing the tasks and duties at different political and

administrative levels.

For planning and goal setting state legislation lays down the duties for the

municipalities to implement waste planning and goal setting. But it also sets the

minimum overall goals to be achieved. As described above the first waste

planning regulation laid down an overall goal of 50% recycling of all waste

from all sources to be achieved by the municipalities. In later amendments the

goals have been somewhat more specified on fractions and sources. But

generally the municipalities still have to carry out the planing and decide on

which fractions and waste producers to focus on, based on the local distribution

of businesses and population.

State legislation then delegates the powers to implement the planning to the

municipalities. The powers first of all include the legislative powers to issue

regulations on waste production, storage, sorting and handling from all sources,

including businesses, offices, public institutions, constructions sites etc.

Secondly the powers include the right to collect fees from all types of waste

producers for the cost involved in waste management including public planning

and administration, collection, treatment and recycling, inspection and

monitoring and enforcement.

30

The traditional supply aspect - to collect and dispose waste is maintained as a

purely municipal task. State legislation prescribes a municipal duty to collect

and dispose waste from all sources - including businesses, construction sites and

institutions. The above mentioned duty to collect household waste from towns

with more than 2,000 inhabitants today is substituted with a general duty to

collect and dispose the waste from all sources. As described above this duty can

be carried out through inter-municipal or municipal operation, by contracting or

by authorisation and permit systems. But the responsibility still solely lies in the

hands of the municipalities.

The regional administration in Denmark deals with the physical planning,

including approval of the locations for municipal incinerators and landfills. But

the state might give certain specific directives. E.g. landfills can only be situated

along the coast due to the risk for polluting the groundwater.

The regional councils also issue the environmental approval of the municipal

waste facilities.

Some issues are still purely state matters. The use of economic incentives is a

state issue. Already in 1977 the state imposed a tax on glass containers for

certain products. Since then several taxes has been imposed on different

products, especially for packaging. A tax on 0.60 RM on plastic bags is an

example. Taxes on waste disposal have been introduced. For landfills the tax is

RM 160, for incineration and energy utilisation it is RM 120, and for recycling

no tax is imposed.

On the other hand state funding has been established for developing and testing

new technologies in waste collection, recycling and disposal as described above.

Finally the regulation of the use of materials is a state matter. Ban on the use of

certain materials like certain solvents, CFC etc. is an example. Restrictions on

the use of materials for different purposes are similarly a state issue. The

restrictions might be imposed by regulation or by agreement with a specific

industry. An example covering the phasing out the use of PVC for most of the

products where it has been used until now is described above.

WASTE MANAGEMENT TASKS AND DUTIES IN SARAWAK

Today no coherent waste management system is established in Sarawak.

Hazardous (scheduled) waste is administered by the federal DOE. No specific

industrial waste scheme is established but DOE generally administers

31

environmental issues related to industries. Waste from public institutions is

typically administered by the ministry/council in question.

The local authorities administer domestic waste, mainly including waste from

households, markets and commercial enterprises.

The administration of domestic waste is by tradition still addressed as a service

or health (cleanliness) issue as it was the case in Denmark in the 60es, as

described above. The issues addressed in the Local Authorities Ordinance are

mainly collection, removal and disposal (LAO sect 105).

The tasks are typically formulated as "may" provisions (mandates) for the local

councils, but the powers are not followed by the duty to carry out any task. This

makes the establishment of coherent cross-municipal waste management

difficult. Only the provision to keep the area within the jurisdiction of the Local

Council clean is a duty (shall). (LAO sect 98). In spite of the lack of express

duties the local councils in practice carry out different recycling schemes and

awareness campaigns.

No overall waste planning and goal setting task or duty is defined. No public

entity has the mandate or the duty to carry out overall planning for the level and

quality of waste handling to be achieved.

Neither is any physical planning for waste management prescribed. The

planning and location of facilities (landfills, sludge treatment etc.) is dealt with

individually. Generally the local councils has no legal mandate to carry out

planning.

For Kuching the waste collection and disposal has been contracted out to a joint

German (Trienekens)/Sarawak government company. The consequences for

maintaining the ability for directing state or local authorities to carry out waste

planning and goal setting in the future will depend on the content and the

duration of the contract signed. The waste collection and the removal of waste

carried out hitherto by the local councils in Kuching has been carried out at a

high sanitary standard, maintaining Kuching as a clean city, compared to many

Asian cities. Sanitary problems have mainly been recognised in connection with

waste disposal.

Economic incentives and restrictions on the use of materials have so far not

been used as waste management measures in Sarawak.

Although no duty is formulated, waste regulations in Sarawak today actually

provides Local Authorities with mandates to establish a highly advanced waste

management system similar to the systems in other advanced countries.

32

According to LAO sect 91, the Local Authority can issue by-laws on cleanliness

and disposal of waste. According to sect 105 a local authority might issue by-

laws on waste collection systems for any waste fraction and type of waste

producer (any premises), and the waste producers (owners or occupiers) are

obliged to effect such systems.

The provisions are specified in the 1999 cleanliness by-law (LAC). According

to section 9 in LAC, the local councils might issue directions on the manner in

which waste from the premises should be handled, prepared or deposited for

collection and removal. These directions might be made applicable to the whole

area, parts hereof or to any type or class of premises. This mandate is in

principle similar to the Danish regulation on issuing waste regulations.

According to sect. 51 in LAC, the Local Authorities may licence transport and

disposal of industrial waste. Disposal expressly includes recycling. This could

imply that the Local Authorities have the power to impose specifications on

transportation of waste in specified fractions and to withdraw licences from

waste collection and treatment companies that does not comply with the

conditions for the licensing. However, the scope of the conditions that might be

imposed for licensing is not express formulated. In Denmark licensing has

shown to be a very efficient tool to ensure high quality in waste management.

To ensure a comprehensive waste management system, a current flow of data on

waste production, transport and treatment is crucial. According to LAC sect 47,

the Local Authorities might require all data needed. But still this request cannot

be given in a general form for ensuring a continuous flow of data. The request

has to be given concrete and repeated from time to time, which obviously sets

clear limitations for the flow of data.

In addition the bylaws include provisions on storage and periodically removal of

waste from work places or premises, on illegal dumping, and on final disposal.

Also the by-laws include mandates for regulating toxic waste, including

reduction in the amount of toxic waste produced. The delimitation to the tasks of

DOE regarding industries and scheduled waste is not clear.

33

CONCLUSION

In both Denmark and Sarawak waste management is an issue for local

authorities. The historical background for locating waste management as an

issue for local councils has been the focus on the service aspects of waste

management, which typically is an issue for local entities.

When waste management in Denmark the 70es changed its characters from

purely a sanitary service issue towards political goal setting for individual waste

fractions and for individual waste sources, the municipalities in some senses

became too small to manage the operations cost efficiently. In Denmark this

problem was faced without changing the level of authority. The Danish

municipalities voluntary created inter-municipal partnerships, optimal in size for

dealing with the new issues.

Generally waste management in Sarawak is still at a premature step compared to

the state of the art to day. But the legal preconditions for fast progress is

certainly in place. The coming years deserves to become the sparkling period for

local waste management in Sarawak.

Literature

Lit. 1: Ib Larsen

»Waste Minimisation and Recycling in Denmark«

Proceeding for the ISWA Annual Conference, Amsterdam 1990

Agency of Environmental Protection, City of Copenhagen, 1990

Lit. 2: Ib Larsen

»Organic Wastes« Paper for the IULA-congress, New York 1990

»World Congress for a Substantial Future«

Agency of Environmental Protection, City of Copenhagen, 1990

Lit. 3: Ib Larsen, Kit Børrild

»A Coherent Regulatory System for Commercial and Industrial Wastes,

in the City of Copenhagen« Paper presented at the ISWA Conference

»An Integrated Approach to Solid Waste Management« Toronto 1991

Agency of Environmental Protection, City of Copenhagen, 1991

35

ON ODOUR, ODOUR MEASUREMENT AND REGULATION

Arne Oxbøl

Project Manager

dk-TEKNIK Energy & Environment

Denmark

INTRODUCTION

This presentation will present how odour is analysed in Denmark and the

experiences gained at a 2 weeks introduction for odour measurements held in

Kuching. It will also discuss how this method can be used in Kuching and how

it can benefit the environment in Kuching.

WHAT IS ODOUR ACTUALLY?

Odourants are volatile compounds which can be perceived (smelled) by the

human nose.

Unlike other pollutants like NOx, SO2, CO and dust most people with a normal

sense of smelling can perceive the odour. To measure the other pollutants it is

necessary to use a monitor.

Odour is an individual experience which is illustrated by Figure 1.

Figure 1 Odour is an Individual Experience

36

And every individual has different experiences with the same odour at different

times and in different situations. Having a dinner in a restaurant, the smell from

the kitchen is tantalising. However, to live in an apartment above a restaurant,

the smell may become too common to an extend it becomes odour.

Odour is caused by e.g. chemical processes or biological activity in e.g.

wastewater treatment plants or in drains or polluted rivers. A lot of the

compounds which are formed might even smell in low concentrations. It would

be a huge task to analyse all these compounds individually and, consequently it

is easier to just determine the accumulated odour deriving from all the

substances.

For an odour analysis, there is always an assumption that no toxic compound is

present in the air. If toxic compounds are present in the air, that is a more

serious problem than the odour itself, and therefore, that problem should be

solved first. Odour is not toxic but nevertheless a nuisance, and therefore it is of

great concern in Denmark and other European countries. Odour emission from

businesses and other activities is therefore regulated in most European countries.

When the odour concentration from e.g. a wastewater treatment plant has been

determined, the nuisance in neighbouring areas can be calculated. In Denmark, the

authorities use this documentation for regulating the industry. It is also used to

determine what actions are required at wastewater treatment plants to reduce the

nuisance.

HOW DO WE DESCRIBE THE QUANTITY OF ODOUR?

The concentration of odour is not an absolute value as, for instance temperature

or the pH or content of COD. Some people have better noses than others and the

conditions under which the analysis is performed are very important.

Even for one specific individual, the sense of smelling may change with time. If

a person has caught a cold, has allergic reactions or has eaten spicy food etc.

his/her sense of smelling changes. Consequently, it is necessary to have well-

defined conditions for the analysis.

A few definitions are necessary to know:

One odour unit: The amount of an odourant or mixture of odourants, which

causes the intensity of exactly the odour threshold when distributed in 1 m3 of

air or water.

37

Odour threshold: The concentration of odourant at which 50% of a panel of

panellists can recognise the odour in a sample and the other 50% can not.

Threshold odour number (TON): The number of dilutions of a water or air

sample necessary to obtain a mixture where odour is just recognised with

certainty by the panellist. One sample from the Petanak Market smelled heavily.

After having diluted it 6000 times, it was just possible to perceive the odour. In

that case, the TON is 6000.

Another parameter is the intensity which describes how strong the odour is at a

certain concentration. The intensity is different for different odours. This is

shown in Figure 2 presenting the intensity of odour from two types of industry.

Figure 2 Odour Intensity Curves

The Figure shows that the odour from a pig stall always, is stronger than the

odour from a tobacco factory, at the same concentrations. 5 OU/m3 from a pig

stall gives an unmistakable odour, while 5 OU/m3 from the tobacco factory only

gives a weak odour. At 13 OU/m3 the odour from the tobacco factory is

unmistakable, and the odour from the pig stall is more than strong.

The smell from pig farms in Sarawak, is of great concern. By means of an odour

analysis it is possible to describe the extent of the problem.

38

HOW DO WE ANALYSE THE ODOUR?

At present, no objective, physical or chemical measurements exist, and so far,

using an apparatus to obtain a precise value is not possible. Relying on the

human nose is needed, which is still superior to any apparatus device.

Odour analysis can be done in several ways depending on the purpose. It is

possible to measure odour in the air or water or from materials or people (Figure

3).

Figure 3 Odour Analysis on a Deodorant Factory

A factory producing deodorants tests how the deodorants perceived by letting

ladies smell men's armpit. Body odour is one of the most repellent odours.

But in all cases, a panel of smellers is necessary to obtain good results:

The panellists are not people with especially good or big noses. The panellists

must, however, fulfil some personal demands, which are as follows:

1. No cold or allergic reactions on the day of the analysis;

2. No eating (including chewing gum), drinking (except water) or smoking

within 30 minutes before the analysis;

3. No eating (including chewing gum), drinking (except water) or smoking

during the analysis;

4. Proper, discrete hygiene without strong perfumes;

5. Good motivation; and

6. No communication between panellist during the analysis.

The panellists are selected among adult people. The sensitivity of the noses of

the panellists is calibrated with a reference odourant (n-butanol) before they

39

enter as a panellist. Based on this calibration the spreadsheet programme can

compensate for the differences in sensitivity.

The training of panellists mainly consists of letting continue conducting smell

tests until they feel confident with the procedure. When the tests are done, the

results are calculated, and if they are within some limits and the repeatability is

fine, the panellist is accepted.

How do we measure smell in Kuching (Odour Water)

The method which has now been introduced in Kuching is based on determining

the level of odour in a water samples. In principle the method is relatively

simple, but of course, it is necessary to have skilled laboratory staff and skilled

panellists to obtain good results. The procedure is based on an American

“Standard method for the examination of water and wastewater”, a European

standard for odour analysis and finally on the knowledge and experience of my

company.

The laboratory staff prepares a series of dilutions, starting with a highly diluted

sample which no one can smell, and increases the concentration of odourant

until all the panellists can smell it. The dilutions are presented for the panellists

together with blanks (bottles with plain water) which are randomly distributed

among the dilutions and with one blank as a reference. The panellists work one

by one.

Each panellist starts with smelling to the first bottle (lowest concentration) and

tells whether he/she is sure about an odour or not. If he/she is not absolutely

sure, the answer is NO. Then the panellist continues with the next bottle.

After completion, he/she shall describe the odour as e.g. sweet, drain, fishy or

whatever he/she feels. This description is used to help in finding out what is the

cause of the odour. If e.g. the panellists indicate a fishy odour, it probably has

something to do with a fish market or a fish factory. Then it is easier to look for

the source and do something about it.

When all panellists have completed the tests, the positions of the blanks are

changed a little, and the second round is done the same way. The operator notes

the answers on a piece of paper.

When typing the answers into a spreadsheet the calculations are done

automatically by the computers.

40

A report is also made automatically in a spreadsheet as shown in Figure 4.

Figure 4 Example of a Report on Odour Analysis

Method for analysis of odour in air

Alternatively to the method introduced in Kuching, odour can also be measured in

air samples.

The concentration of odourants in air is determined by means of a panel of

panellists and an olfactometer. In an olfactometer the odorous air is mixed with

odour free air in well-defined dilutions. The method is based on the above-

mentioned European standard.

A panel consists of 2 x 3 panellists, who fulfil the same demands and

calibrations as presented in section "How do we analyse the odour" and sub-

section "How do we measure smell in Kuching (odour water)".

Before the analysis starts the operator estimates the odour concentration of the

sample and selects a dilution, at which probably no panellist can smell anything.

The first 3 panellists go to the "smelling box" (Figure 5).

Odour result reportFile no. Journal no. 2001-005

Date of sampling Samples analysed 30-04-01 Projectmanager Penny Sumok Operator Hayati

Test no. Measured parameter values Threshold 95% confidence interval n-butanol

Sample no. pH Temp. Par3 Par4 odour number Lower limit Upper limit threshold

1 Water Water Water ? 58 35 95 3,5

Std. 1 Laboratory 12.00 Sweet Water Sweet

2 Poultry wasteWater Water Soil 242 147 397

1 Sungai Bintangor 9.30 Rubbish ? Rusted iron

3 Alcohol Light Sweet Leaf 39 24 65 5,1

Std. 2 Laboratory 12.00 Water Sweet

4 Poultry wasteDrain Urine Soil 561 341 921

2 Pasar Besar Petanak 9,45 Fishy Fishy Rusted iron

Customer SUD

30-04-01

Sampled at Time Odour characterisation

41

Figure 5 Tubes with Odorous and Odour Free Air Respectively

In one of the tubes A or B, there is a dilution of the odourant and, the other, is

odour free air. The panellist must select the tube where he/she thinks the odour is.

The panellist must also indicate whether he/she is sure or not sure. An answer is

correct if the panellist chooses the right tube and is sure.

The first mixture is followed by mixtures with increasing concentrations (less

dilution) until all panellists have perceived the odour.

The calculation is exactly the same as that described in sub section "How do we

measure smell in Kuching (odour water)".

After each sample the panellist shall describe the characteristics of the odour.

HOW DO WE TAKE SAMPLES FOR ODOUR ANALYSIS?

When testing smell in water, we simply dip a can or a bottle in the river or drain

to fill it.

In Denmark, the analysis of air is different. When odour becomes a problem, it

is because the wind blows over the surface and takes up the odour and brings it

to the neighbours. The method is then based on creating a similar wind blow at

the surface of the water. When sampling air from a water surface, a bottle

without bottom is used and it is placed on the surface. Then nitrogen is blown

over the surface inside the bottle (like the wind) and collects it in into an odour

free plastic bag.

It can be done either directly on the surface (Figure 6) or at the laboratory, if the

sample is brought home.

42

Figure 6 Sampling from An Area Source

The principle can also be used for solids as e.g. compost or solid waste.

To take a sample from a stack of a factory or from a pig stall, a little drum with

vacuum is used (Figure 7).

Figure 7 Air Sampling System

The principle is that a small pump creates a small vacuum inside the drum. A

plastic bag is placed in the drum and connected with a tube to the stack. The

vacuum then sucks air into the bag.

43

HOW DO WE REGULATE THE ODOUR?

In Denmark, the Environmental Protection Agency has stated that no industry

must cause more than 10 OU/m3 in residential areas. Environmental regulation

has been issued stating that, if an industry causes more than 10 OU/m3 the local

council can demand the factory to reduce the emission of odour, before it is

allowed to continue the production.

The emission itself from the factory is not the background for regulation. The

interesting figure is the immission – the impact on the environment, which

might be residential areas. The immission is calculated by putting the measured

odour emission levels into a computer-based, meteorological spread-calculation

programme. To use the programme, information on the odour emission

concentration, the size of the source and the physical conditions in the

surroundings need to be key in.

The result of the calculation can be illustrated as a map of the area with the

factory in the centre, where isolines show the concentrations (Figure 8).

Figure 8 Illustration of Propagation of Odour around a Pig Farm

This example is from a pig farm, where the emission of odour is measured and

the immission is calculated. The pig farm is located in the centre of the map. Pig

farms in Denmark can be very big with thousands of pigs, and the odour is very

significant. Each isoline delineates the area where the concentration is above the

value. In this case the odour level is approximately 100 OU/m3 100 metre from

the farm. 500 meters away, it is still 20 OU/m3, and we need to go 800 meters

away to find an acceptable level of 10 OU/m3. Because a residential area is

inside the critical zone, the local council will most probably order the owner of

the farm to reduce the odour.

44

HOW CAN WE USE ODOUR ANALYSIS IN KUCHING?

First of all, odour analysis is a tool for monitoring the development in water

quality. It can be done by monitoring the threshold odour number at selected

sampling points over a span of time, e.g. a year. Dk-TEKNIK has proposed a

monitoring program including the four streams that flows into the Sarawak

River from the city, the riverfront near the centre of the Sarawak River itself and

a reference point upstream. When the odour is measured regularly (e.g. every

fortnight), we will be able to get a picture of the level of odour at each sampling

point. If there is an increasing trend due to increased population or increased

activities, we will also be able to discover that. After one year of measurement,

we will have a clear picture of where the problems are located.

It is also possible to correlate the threshold odour number determined here in

Kuching to odour concentrations in the less polluted neighbouring areas.

Consequently, it will be able to estimate what threshold odour number should

not be exceeded. And then the authorities have a tool in their hands with which

they can regulate the sources of odour.

Secondly, a survey of complaints on odour can be made and areas where odour

is a particular problem can be found. If the problems are caused by water

sources, this method will assist in finding the main source.

A company like dk-TEKNIK and the NREB laboratory will be able to act as an

advisors to both the councils and the industry having problematic discharge.

In the near future when the NREB extends the activity of the laboratory to

include analysis of odour in air, the regulation activities could be extended to

cover air emission from e.g. factories and pig stalls.

45

DANISH EXPERIENCES IN COLLECTING AND TREATING

ORGANIC WASTE FROM BIG KITCHENS

Soren Eriksen

Project Manager

R98 Cleansing Company

Denmark

INTRODUCTION

This paper describes the Danish regulation on collection and treatment of

organic waste from big kitchens according to which such waste should be used

as pig feed. The paper also describes the background of the regulations, the

provisions included in the regulations to ensure correct handling and treatment

of the waste and the actual source segregation, transportation, treatment and

reuse of the waste. It also includes a short discussion on other possibilities of

treatment and recovery and a discussion on the relevance of the scheme for

Kuching.

The paper is based on a presentation given to the Public Health Committee of

Sarawak and a high tea talk held by the SUD project for the major stakeholders

in Kuching.

HISTORY AND BACKGROUND

Kitchen waste, including residues from food preparation and the left-over from

meals, has in fact always been reused. Traditionally, it was used at farms to

feed domestic animals or thrown in the kitchen midding for composting. Also

in the cities, it was used for animal feed. In earlier days, pigs and other animals

were roaming on the streets eating what was left there. Later, a waste collecting

scheme was implemented to help keeping the streets clean for aesthetic and

hygienic purposes. This scheme most often did not allow reuse of, for example,

organic waste since all waste was mixed in one bin.

In 1986, the Danish Ministry of Environment announced that the municipalities

would implement collection of food waste from big kitchens for pig feed. In

1990, a statutory order made this compulsory for kitchens producing more than

100 kg of food waste a week.

Based on this national statutory order, the municipalities had to draw up local

regulations. The regulations of Copenhagen municipality describe the scope of

the scheme including the types of waste and waste producers included. The

regulations also describe the duties of the waste producer, the transporter and the

46

pig feed producer. Finally, the regulations include provisions on a fee structure

and on compliance.

PURPOSE

The objectives of the scheme included:

Decreased use of resources;

Decreased amount of waste for landfilling and for incineration, increased

combustion value of the residual waste for incineration by removal of the

wet food fraction, and avoidance of dioxin generation caused by the

Naturium Chloride content in the food waste; and

Ensure high quality performance of the collection and food production to

avoid veterinary and environmental risks.

IMPLEMENTING THE SCHEME IN COPENHAGEN

The producers who were obliged to participate in the scheme were determined

based on the amount of food waste produced and the producer‟s geographical

location. Producers located inappropriately in relation to easy access or to

practical route planning and, at the same time, producing only limited amounts

of food waste were left out of the scheme to avoid unacceptable high

transportation cost.

Surveying the actual waste amounts to determine which restaurants would be

included turned out to be quite a problem. The original survey was done using

questionnaires and interviews. Very often, customers' estimation on waste

amounts turned out to be very inaccurate. After a detailed survey of the

questionable restaurants, 144 of 388 food producers were included in the

scheme. A few producers with an estimated produced amount close to 100 kg a

week were left out if they argued fiercely against it.

Getting new producers who started their business after the introduction of the

scheme to participate also turned out to be quite a problem. Even though the

new waste producers has to enter the scheme on their own initiative, it became

clear that close co-operation with the authorities responsible for licensing or

approving new restaurants, hotels or other producers is very important to ensure

continuous inclusion of new producers.

Awareness programmes and the training of the producers' staff turned out to be

another important task to ensure proper sorting and to guarantee good hygienic

conditions.

47

MOTIVATING WASTE PRODUCERS

The scheme will only turn out to be a success if the producers, including owners

and staff, are willing to take part and feel responsible for maintaining a high

quality of the food waste.

Motivating factors could be:

Increasing cleanliness in the kitchen, e.g. by the use of dedicated buckets

with lids for the food waste in the kitchen;

Making resource savings more visible; and

Helping to improve the quality of the environment.

Economic aspects have to be considered. Collection costs always increase when

waste is sorted into more fractions that are transported separately.

In Copenhagen, the scheme was originally initiated as a demonstration project

which was free of charge for the producers. In fact, this gave an opportunity for

the producers to save money by decreasing the amount of residual refuse, the

size of which formed the basis for the calculation of the waste collection fee.

Later on, fees for collecting food waste have been introduced. The fee is higher

than those for residual refuse collection and this reduces some producers‟

commitment to source segregation.

COLLECTION METHOD AND EQUIPMENT

Handling at the collection point

In the kitchens, the waste is stored in 16-liter buckets with lids. These buckets

are emptied into larger 90-litre bins that are located outside the main kitchen by

the staff. It is the duty of waste producers to keep the kitchen buckets clean. The

90-litre bins are typically located in roofed or un-roofed backyards. A few of

these bins are kept in closed sheds or inside the building. Some producers use

the 90-litre bins directly in the kitchen to simplify the handling. This is not to be

recommended due to hygienic problems when keeping waste close to fresh food

and because this increases the amount of heavy lifting for the staff. The 90-litre

bins are collected by the collection company.

48

Figure 1 Bins at the Cleaning Plant

50-litre bins are also used where the size of the entrance to the premises does not

allow the use of the standard cart used for wheeling the 90-liter bins. The cart is

used to avoid contact between with the collectors and the waste and to avoid the

risk of overloading the body due to heavy waste. Wheeled 300-400 litre bins are

used at certain locations.

Transportation

Tank trucks are used for collecting the 50- and 90-litre bins from the producer.

A lift is installed on the truck to bring the bins to the loading opening which is

located on the roof of the tank. The emptying is performed automatically to

avoid inhaling of micro-organisms by the staff. The bins are emptied into the

tank at the producer. At the same time as the staff collects the full bin, they

bring a clean empty bin to the kitchen. The used bins are brought back to the

transfer station for cleaning. Both the clean and the used bins are fastened onto

the truck at the sides of the tank during transportation. To ensure that the food

waste is fresh when arriving to the processing plant, the waste is collected at

least every 3rd day and usually every 2nd day.

The trucks can load 2-3 tonnes of waste. The carrying capacity is not limited by

waste amount, but by the number of empty bins the truck can carry. The truck

can carry about 100 bins.

49

A platform truck is used for the 300-400 litre wheeled bins. In Copenhagen, a

double platform truck is also used for carrying bigger loads. When using the

platform truck, it is not possible to empty the bins at the producers. This needs

to be done on the transfer station.

The waste is brought to a transfer station which also includes the bin-cleaning

facility. Here the waste is reloaded into 16-cubic-metre roll-on containers. These

containers are then transported to the processing plant. The reloading takes place

to decrease transportation cost.

Figure 2 Tank Truck Collecting at the Producer

The processing plant is located in the countryside 50 km outside Copenhagen.

Cleaning bins

To ensure good hygienic conditions and avoid rotting of the food waste, the bins

have to be cleaned in every collection. In Copenhagen, the bins are cleaned at a

centralised cleaning facility located at the transfer station. Only a few producers

have got their own washing facilities due to the strict hygienic conditions and

the very often the limited space for such purposes at food outlets in the city

centre. Own washing facilities would reduce cost much, since bins would not

need to be brought to the cleaning facility.

Another system used in other parts of Denmark includes emptying of the bin

directly into the roll-on container which is transported directly to the processing

50

plant. This system requires the producers to clean the bins. In a third system, the

full bins are brought directly to the processing plant, and cleaning of the bins

takes place at the processing plant.

PROCESSING

The regulations on processing of food waste demands that the collected food

waste is boiled for a minimum of 15 minutes, under a pressure of 3.5 bar,

corresponding to 1250C. This is to ensure full disinfection of the product.

Processing directly at the farm

When preparing the scheme for Copenhagen, it was planned to carry out the

processing directly at a pig farm. After boiling the food waste, the pig feed

would then be pumped directly into the automatically operating wet feeding

system at the farm. The on line feeding implied that the expensive preservation

of the food was not necessary. Preservation is needed when the pig feed has to

be transported from the facility to the farms. To utilise all food waste collected

in the city of Copenhagen, the size of the pig farm would have to correspond to

a yearly production of about 90,000 pigs, (100 kg before slaughtering) taking

into account the restrictions for using the food as described below. The pulp is

used for both sows and porkers.

Eventually, this solution was not selected due to complications in negotiations

between the Ministry of Environment and the farmers' association. Instead, it

was decided to carry out the processing at a centralised processing plant

operated by the farmers' association.

Centralised processing

The processing at the centralised facility is equal to the treatment at the pig

farm. The main difference is that the food has to be preserved before distribution

to the customers. This is done by decreasing pH to 4.4 by adding formic acid. In

this concept, the individual farm has to invest in silos to store the preserved pig

feed. The pig feed is transported to the farm as wet feed (pulp). Farmers need a

standing pig population of about 2000 pigs to make investment in fodder-silos

payable.

In one of the two centralised plants in Denmark, large bones and larger alien

elements are sorted out manually at a conveyor-belt. Maintaining satisfactory

hygienic conditions for the employees at the conveyer belt is very difficult, since

51

the staff is in close contact with the food waste. In the second plant in Denmark

pre-sorting is therefore left-out. Metal items are instead settled in the pre-

sorting silo. In addition, the mincer will stop if larger metal items have been able

to pass the boiler.

Processing for biogas

The waste can also be processed for biogas exploiting the energy resources in

the waste. Remnants can be used for composting. Calculations made by Danish

pig fodder producers shows that energy exploitation is marginally higher when

processing for pigs fodder than for biogas.

The net energy gain from producing pigs food (energy content in the pig waste

subtracted less the energy used for processing) has been calculated at 2900 MJ

per 1000 kg food waste, while the net energy gain from producing biogas has

been calculated at 2600 MJ.

Composting

Composting of the waste makes recycling of organic material possible and

avoids landfilling and incinerating of the waste, but it does not really allow

exploitation of the energy content of the waste. Composting could be a

temporary solution, since investment costs are quite low.

WASTE AMOUNT

The food waste potential from big kitchens in Denmark amounts to 20,000 –

25,000 tonnes per year from restaurants and 10,000 – 30,000 tonnes per year

from trade/industry.

About 19,000 tonnes is collected a year. This shows that the existing level of

collection is high and indicates that the producers are very committed.

An average of 184 kg per week is collected from each participating kitchen

enrolled. For comparison, the potential of organic waste from private

households in Copenhagen is only 50 kg a year.

52

FOOD PULP

The food pulp processed from food waste can substitute no more than 20% of

the fodder due to the high content of salt and fat in the fodder.

Since the value of the pulp for fodder is 90% of the common fodder (barley) and

the price is only 75% of the price for barley, there is a high demand for pulp.

The overall cost of producing the pig feed does not allow prices like this. The

price is therefore supported by national regulation which requires the wastes

producers to pay the deficit.

The existing demand for food pulp in Denmark is about 60 times higher than the

produced amount, so there is no limitation for the production of the pig feed due

to lacking demand.

The pulp can also be used for mink or dog feed, but this has not yet been

introduced.

QUALITY OF WASTE

To ensure healthiness for the pigs and a high quality meat production, a very

high quality of the pig feed is necessary. Not more than 3 mg alien elements per

tonne of waste is allowed in the pulp. It is very important to avoid rotten

products as a very small share of rotten food waste can destroy big loads.

To ensure the healthiness, the following aspects are taken into consideration:

Training of producers;

Collection frequency (usually every second day in Denmark);

Cleanliness of bins, containers, trucks and processing plant;

Functionality for picking up alien elements during processing; and

Inspection of produced pulp before distribution.

The quality of the waste delivered to the processing plant is very high due to the

great commitment of the producers.

53

ECONOMY

Producer

The cost for the waste producer is higher than that of delivering the residual

refuse. In spite of this, the producers are very efficient in sorting the waste.

However, some producers in Copenhagen have complained that the prices are

too high. This has initiated some activities to achieve a higher degree of

efficiency:

Cleaning the bins at the producers (saves transportation);

Cooling down the waste at the producer to decrease the necessary collection

frequency and thereby transportation cost; and

Use of waste bags instead of bins to avoid cleaning of bins.

Costs and fees

Production costs in Copenhagen can be split up as follows:

Collection 50%

Cleaning of bins 20%

Transportation from transfer station to processing plant 15%

Processing 15%

The collection company charges the producers for the cost of collection and

cleaning the bins. The charge also includes the deficit between the costs of

processing and the income from the sale of the pulp. In Copenhagen, the fees

have to be approved by the city council.

COPENHAGEN VERSUS KUCHING

Different aspects have to be taken into consideration when comparing the

conditions in Copenhagen and Kuching:

The climate is hotter and more humid in Kuching than in Copenhagen. This

makes even higher demands on storage facilities, collection frequency and

cleanliness of bins, trucks and processing plant;

The importance of the scheme is greater in Kuching than in Copenhagen, as

Kuching has a large extent of illegal discharge or disposal of food waste into

streets, drains and streams; and

54

Composting of the waste might be an alternative solution for Kuching as a

first step to keep down costs as economy consideration could reduce the

commitment of the producers to the scheme.

Obviously, it is not possible just to copy the Danish solution in Sarawak, but the

experiences from Copenhagen can be utilised when preparing a scheme for

Kuching. Conditions in these two cities are very different, but both have same

goal of keeping down the impact on the environment and reducing the use of

resources.

55

THE CHALLENGE OF RECYCLING CONSTRUCTION AND

DEMOLITION WASTE - FOCUSING ON THE CITY OF KUCHING,

SARAWAK

Erik Lauritzen

Director

DEMEX Consulting Engineers A/S

Denmark

ABSTRACT

This paper presents options and barriers for the implementation of integrated

recycling and construction and demolition (C&D) waste management, based on

experience and results from demolition and recycling projects in Scandinavia

and other countries around the world. The paper also presents the options and

recommendations for C&D waste management in Kuching, which were

introduced at the seminar in Kuching on 16 May 2001.

KEYWORDS

C&D waste, demolition, economy, recycling, reuse of waste cleared after wars

and disasters, resources management, integrated C&D waste management in

Sarawak

THE NEED FOR BUILDING WASTE MINIMISATION

In all communities it has always been common practice to retrieve valuable

materials from the arising waste, e.g. metals and building materials. After some

decades with an extensive "use-and-throw-away" philosophy in the end of the

last century it has now been recognised that we cannot continue this uninhibited

use of natural resources and pollution of the world. It is necessary to change our

habits and to revise former common practices within the building and

construction industry, as well as within other industries, households etc.

In the last decades many "green" movements arose, most of which were based

on political and idealistic issues, and unfortunately made rather a limited impact

on practical life. However, within the last few years the World Bank and OECD

have emphasised that the recycling of waste and the introduction and

implementation of environmentally friendly technologies must be considered as

one the greatest technological challenges of our time. To encourage the

achievement of these objectives the World Bank has clearly stated that the

56

improvement and protection of the environment is a question of money, why

improvements should be supported by the developed countries.

Another great technological challenge is to prevent, or at least reduce, damage

to cities and to protect society from the causes of natural disasters. Natural

disasters and technical - or man- made - disasters, especially wars, generate

large amounts of building and industrial waste.

In many countries, industrialised as well as developing, C&D waste is con-

sidered as harmless, inert waste, which does not give rise to problems. However,

C&D waste constitute huge amounts and are often deposited without any

consideration, causing many problems and encouraging the illegal dumping of

other kinds of waste. Furthermore C&D waste typically include a certain

percentage of hazardous materials.Whether C&D waste originates from clearing

after natural disasters or from human-controlled activities the utilisation of such

waste by recycling can provide opportunities for saving energy, time, resources

and money. Furthermore, recycling and controlled management of C&D waste

will mean that less land is required for waste disposal and thus better

opportunities will be avaiable for the disposal of other kinds of waste.

C&D WASTE STREAMS IN THE EU

C&D waste derives from normal demolition, rehabilitation, and new

construction works, as well as from natural and technological disasters.

Production of building materials also gives rise to waste fraction similar to C&D

waste. These waste fractions includes surplus ready-mixed concrete, concrete

elements, articles of wood etc.These waste fractions might be classified either as

C&D waste or as industrial waste.

Table 1 Typical Fractions of C&D Waste in Denmark

Material fractions

Type of

building

Brick/concrete

%

Wood

%

Steel

%

Other

%

Total in t/m2

Industrial 90 2 4 4 1.1

Residential 86 12 0 2 1.4

In the European Union, which has a population of approximately 350 million, it

is estimated that the annual generation of C&D waste is approximately 180

million tonnes - equivalent to ½ tonne per capita per year. In total 28% of the

waste is recycled, as shown in Table 2 (Symonds et al. 1999).

57

Table 2 C & D Waste Arising and Recycling

Member State 'Core' C & D Waste

Arising (m tonnes,

rounded)

% Re-Used or

Recycled

%

Incinerated

or landfilled

Germany 59 17 83

United

Kingdom

30 45 55

France 24 15 85

Italy 20 9 91

Spain 13 <5 >95

Netherlands 11 90 10

Belgium 7 87 13

Austria 5 41 59

Portugal 3 <5 >95

Denmark 3 81 19

Greece 2 <5 >95

Sweden 2 21 55

Finland 1 45 >95

Ireland 1 <5 n/a

Luxembourg 0 n/a 72

EU-15 180 28

Table 3 Average Costs and Prices in EU Member States in ECU

per Tonne (1996)

Disposal

Costs:

Transport

Costs:

Crushing

Costs:

Recycled

Material

Price:

Quarry

material

Price:

All states

Denmark,

The

Nederlands,

Germany

1-35

24-35

2.6-7.3

2.6-7.3

2.43-6.52

5.36-6.52

3.24-7.17

5.23-5.88

4.54-8.45

6.37-7.61

Recycled materials are generally less expensive than natural materials. In

Germany, Holland and Denmark recycling is furthermore less costly than

disposal, due to the extensive requirements for sanitary landfills. Most EU

member countries have established goals for recycling that range from 50% to

90% of their C&D waste production, in order to substitute natural resources

such as timber, steel and quarry materials.

58

GOALS FOR RECYCLING

At present very limited amounts of C&D waste are recycled as high-value

materials, such as recycled aggregates in new concrete. The majority of C&D

waste is disposed of at dumping sites or recycled as crushed mixed filling

materials for roads etc. Since the amounts of C&D waste are constantly

increasing, there are many reasons for focusing on methods which will promote

recycling of C&D waste (landfill fees in Europe and the USA are typically from

US$ 20-50 per tonne). Present results in Europe show very favourable recycling

possibilities in this field.

From a purely economical point of view the recycling of building waste is only

attractive when the recycled product is competitive with natural resources in

relation to cost and quality. Recycled materials will normally be competitive

where there is a shortage of primary raw materials as well as suitable disposal

sites. In other situations incventives or regulation are required to increase

competiveness of recycling.

With the use of recycled materials, economic savings in the transportation of

building waste and raw materials can be achieved, as illustrated in Figure 1. In

larger recycling projects, such as urban development, renovation of highways, or

clearing of war/disaster-related damages, the total project cost will be dominated

by transportation costs. These transportation costs involve the removal of

demolition products and the supply of new building materials. In these cases the

use of recycled materials is very attractive.

59

Figure 1 Macro-economic Model of Integrated Resource Management and

Total Costs of Traditional and Selective Demolition

Figure 1 shows traditional construction and demolition where all natural

resources are new and all demolition wastes are tipped. The figure below shows

construction, selective demolition and recycling, where a proportion of the

natural resources are substituted by recycled materials from demolition. This

option often saves costs of transport, supply of natural materials and disposal of

demolition waste. The total costs will be less than the total costs of traditional

construction and demolition

BARRIERS TO RECYCLING

In order to reach the goals of C&D waste management, it is necessary that all

barriers and obstacles are detected and considered. The overcoming of these bar-

riers must be planned and carried out through a long-term action plan combined

with adequate research and development. Implementation of recycling systems

requires that the necessary legal, economic and technical instruments are made

available.

60

Economy

If the consumption of building materials is regulated solely by the market

economy the choice between recycled and new materials depends upon price

and quality.

The quality of concrete with recycled aggregates can be the same as that of

concrete with primary natural aggregates, but recycled concrete aggregates are

traditionally regarded with suspicion. Hence, recycled concrete materials will

often only be preferred where the price of such aggregates is considerably lower

than that of the natural materials, even when the recycled aggregates meet the

expected specifications.

With reference to a Danish pilot project – “the Recycled House Project” in

Odense, Denmark, the quality of old bricks and timber might be even better than

new materials.

Introducing economic instruments, which encourage recycling and the use of

recycled materials, can overcome the economic barriers. Several countries have

introduced special taxes and fees in favour of recycling. For example, in 1986

the Danish government introduced a tax on waste, which is not recycled but

disposed of at landfill sites. Today the tax is DKK 375 (approx. MYR 150) per

tonne of waste, which is disposed of at landfill sites. In addition regulation and

enforcement of the C&D waste generation and handling can direct the waste

towards recycling. This is especially the situation in Denmark.

Policies and strategies

C&D waste must be considered as a specific individual type of waste associated

with the building and construction industry, which should be regulated and

handled specifically. It is important to get the industry itself to take reposnsibily

for proper management and handling of the C&D waste. Generally, the building

and construction industry is relatively conservative, and changes in normal pro-

cedures often take time and require long-term policies and strategies.

One of the most critical barriers is the many public entities involved in

management of building waste. Usually, it is the environmental departments and

offices who prepare the policies and issues concerning waste recycling and

reduction, whereas the policies and issues concerning the building and

construction activities themselves are controlled by departments and offices

which are concerned with housing, construction and public works. To co-

ordinate the interests of all parties, particularly with respect to the

61

implementation of cleaner technologies in the industry, it is necessary that long-

term policies and strategies are prepared and implemented.

Danish experience in this field has led to the recommendation that long-term

strategies, e.g. for 10 years with respect to achieving goals for the recycling of

C&D waste, should be adopted. These must then be continuously revised in

accordance with the experiences achieved and the political priorities, and

supported by adequate legislation and regulation at all levels - national, regional

and local.

Monitoring and follow up

Finally, a monitoring and evaluation system must be prepared and maintained

continuously.

It is recommended that monitoring of the C&D waste management should be

incorporated in the general monitoring system.

In Denmark a nationwide solid waste reporting system – ISAG – has been

installed. The system receives detailed information on the handling of all

construction and demolition waste in the country.

Certification of recycled materials

Demolition and crushing techniques for the production of recycled materials are

well known and based on existing technologies. However, some changes in the

demolition process, compared with traditional demolition, are required as

described below, if the recycled materials are to be used for high quality

purposes. Even when recycled materials fulfil current standards for natural

materials, and even when the prices can compete with the prices of natural

materials, certain barriers still exist.

Owing to tradition and psychological barriers the general attitude towards

recycling in the building and construction industry is largely prohibitive towards

the utilisation of recycled materials. Therefore, it is of great importance that

recycled materials are officially certified and accepted by all parties in the

building and construction industry.

It is recommended that considerable emphasis be placed on specifying the fields

of utilisation of recycled C&D waste and setting quality standards for recycled

materials. These must be in accordance with the local demand in order to

improve confidence in the recycled materials and solve problems regarding the

responsibility of using such materials.

62

Planning demolition projects

A necessary condition for the recycling of building waste is careful sorting of

the waste. Waste from new construction sites and rehabilitation works is sorted

either at the production site or at a special treatment site. This separation into

materials categories is fairly simple.

To undertake the sorting of waste from demolition is, however, a more compli-

cated process. Demolition has until recently been regarded as a low techno-

logical process. Rapid demolition and disposal of structures were the main aims

of the contractor. Special measures to separate the different types of materials

were not encouraged, due to the time factor, nor were they desired.

High quality recycling of C&D waste requires that the materials are sorted in-

situ and in co-ordination with the demolition process. It is therefore necessary to

alter the traditional methods of demolition and introduce selective demolition.

This requires that before and during the demolition process an effective sorting

of the different materials categories is carried out, thereby preventing any mix of

materials leading to pollution of, for instance, recyclable concrete/masonry

rubble by wood, paper, cardboard, plastics etc. Since selective demolition takes

more time than traditional demolition, detailed planning is considered as

mandatory.

It is recommended that demolition projects should be planned and controlled in

detail, in the same way as all other building and construction projects, to ensure

selective demolition and correct handling of the demolition waste.

C&D WASTE MANAGEMENT IN SARAWAK (KUCHING),

MALAYSIA

The Sustainable Urban Development (SUD) in Kuching, Sarawak, Malaysia has

taken the first steps towards analysing the feasibility of an integrated C&D

waste management system for Kuching. Initial baseline studies have been

carried out, including visits to selected construction sites, in order to assess the

C&D waste generation and identify the waste stream.

Kuching has approximately 500,000 inhabitants and a considerable rate of

growth and development. Owing to the fact that the development of the city

takes place over a wide area, the need for demolition in the context of urban

development is rather limited. However, there is a considerable need for the

handling of construction waste, especially the huge amount of wood waste. It is

noted that the access to natural gravel resources is very good in Sarawak, and

that transportation is easy and cheap. This indicates that high quality recycling

63

of pure concrete and masonory rubble might not be very profitable on a pure

market basis.

Based on a short visit to selected building sites in Kuching, 14 – 15 May 2001,

and the European experiences on C&D waste generation it is assessed (“best

wild guess” at an initial stage) that the amount of C&D waste generation in

Kuching will reach figures of 250 - 500 kg per inhabitant per year which makes

125,000 – 250,000 tonnes per year.

With reference to the seminar on integrated building waste management held in

Kuching on 16 May 2001 and the SUD Project Draft Paper (see reference no. 6)

proposals towards C&D waste management in Kuching City are presented in

accordance with the following steps:

1) Framework

2) Setting goals

3) Concept design

4) Implementation

5) Monitoring and follow-up

Framework

First of all a baseline study must be completed, including the assessment of

yearly generated C&D waste specified in main fractions, e.g.:

- Rubble waste (concrete, stones and masonry)

- Scrap metal

- Wood

- Paper, cardboard, plastic etc.

Furthermore, the waste generation must be specified in types of waste

generating activities: demolition, repair and construction of new buildings and in

types of buildings and structures as shown in Table 4.

It is necessary that the C&D waste assessment is based on a life cycle approach

and studies of all processes of the buildings and structures. For instance, it

should be mentioned that the recent waste assessment study conducted by the

SUD-project comprised only a couple of weeks of construction processes, which

is insufficient to assess waste generation during all phases of the construction

work.

64

Table 4 Example of a Table for the Assessment of C&D waste

C&D Waste

Type

Industry

Buildings

Private

Buildings

Public

Buildings

Infrastructure

Roads, installations

Demolition

Repair

New

construction

It is also recommended that waste from the building material industry is

assessed, e.g. saw mills and ready-mix concrete plants etc., and that the

possibilities of managing this kind of waste are discussed.

Naturally, legal and administrative conditions and policies are very important to

the C&D waste management system, especially customer payment, waste

collection schemes, delineation of public and private tasks, regulation regarding

C&D waste etc. All potential barriers must be identified and assessed. One of

the most important barriers is lack of awareness of C&D waste and neglecting

the impact to the environment following illegal dumping. It should be noted that

C&D waste management has different stakeholders and instruments compared

to domestic solid waste management. It is very important that the entire building

and construction sector should be committed to the C&D waste management

system.

Finally the framework should comprise an overall review of adequate recycling

and waste handling technologies appropriate to the conditions in Sarawak. For

instance, the treatment of wood waste should be given special attention due to

the huge amount of wood used in the construction industry and due to the huge

amount of wood waste from sawmills.

Setting goals

Succeeding the baseline study, goals for the C&D waste management system

must be set. The goals must be clear, visibly measurable and achievable.

Suitable benchmarking is strongly recommended.

Some examples of typical goals:

- Total amount of C&D waste to be kept lower than a certain figure, e.g.

100,000 t, per year

- Recycling of more than 90% of the total amount of C&D waste after 5 years

from the start of the C&D waste management system

- Composting or recovering of 80% of all wood waste

65

- Reduction in C&D waste landfilled to 10% of all C&D waste

- Minimisation of transport to waste recycling centre to a maximum distance,

e.g. 15 km from the centre of Kuching City

- Minimisation of construction waste to a certain unit figure, e.g. 20 kg/m2

floor area, or 5% of all materials supplied to the construction site

Concept design

The C&D waste management system should be based on a general concept,

which must be operational, concrete and not too complicated. The concept of

C&D waste management in Copenhagen - the “Copenhagen Model” - is based

on one centralised recycling and treatment facility controlled by the

municipality and operated by a private contractor on a licence basis.

Whereas the Copenhagen Model mainly deals with demolition waste and the

recycling of concrete rubble in order to substitute the requirements of the city

for primary natural resources, it is recommended that the concept of the C&D

waste management of Kuching - the “Kuching Model” - should focus on the

collection and treatment of construction waste and the recycling/treatment of

wood waste.

With reference to the visits to construction sites on 14 and 15 May 2001 it is

very clear that the waste management on the sites needs to be considerably

improved in order to enhance recycling, to improve health and safety conditions

on the construction sites and to save space around the constructions.

66

Therefore it is recommended that the concept design should focus on:

- chrushing of concrete and masonry for sub-base road materials and fill;

- applied technologies for scrap metal handling (down-sizing and

compacting) and treatment of wood (reuse, shredding, composting,

depositing);

- sorting and collection of C&D waste at the construction sites;

- suitable facilities for sorting and treatment of C&D waste;

- capacity building of local waste management contractor(s); and

- regulatory and motivating measures encouraging building owners and

contractors to improve the management of construction waste.

Implementation

Implementation of a C&D waste management system takes time. In Denmark

the full implementation of the management system and the achievement of 90%

recycling goal took nearly 10 years. Much research and development has to be

completed, many lessons have to be learnt and many processes and political

discussions have to be completed and agreed upon. Depending on the political

consensus and enforcement of regulations combined with the stakeholder

commitment, the C&D waste management system in Kuching can be based on

Danish experience and implemented within a couple of years. However, it is still

necessary to make a stepwise approach in order to keep the necessary timing of

- establishing of technical facilities and installations;

- elaboration of legal instruments and institutional structures; and

- capacity building and business development for C&D waste management

contractors(s).

Therefore, it is recommended that an Implementation Strategy and an Action

Plan should be prepared as soon as possible.

Initation of demonstration projects and pilot plants are very inmportant for

testing the concept design and to attract politicians and stakeholders' attention

and convince them that the C&D waste management project is a feasible and

successful contribution to the Sarawak society and environment.For instance, a

pilot plant could comprise sorting facilities, a crushing plant for low grade

recycling of rubble, a wood shredding plant and scrap cutting and compaction

facilities.

Small mobile chrushing plants may be included for chrushing directly at major

construction and demolition sites.

67

Monitoring and follow up

Finally, a monitoring and evaluation system must be prepared and maintained

continuously.

It is presupposed that a general solid waste monitoring system will be

established in Sarawak, and it is recommended that monitoring of the C&D

waste management should be incorporated in the general monitoring system.

SUMMARY AND CONCLUSIONS

Global visions

Based on a "best wild guess" a global C&D waste production of 2-3 billion

tonnes per year is estimated. If 30- 40% of this is concrete an annual potential of

at least 1 billion tonnes recyclable waste will arise, which can replace natural

resources.

There is no doubt that results and experience of European research and develop-

ment can be transferred to other parts of the world and enable natural (primary)

raw materials to be replaced by recycled materials, especially in urban renewal

and rehabilitation projects.

To reach the goal of recycling C&D waste it is necessary to establish an

integrated building waste management and production system covering the

whole life cycle of building materials.

Kuching visions

Based on a “best wild guess” Kuching City produces 125,000 – 250,000 tonnes

of C&D waste per year based on 250 - 500 kg per inhabitant per year, and this

amount of waste justifies the establishment of a specific C&D waste

management system focusing on construction waste and wood waste.

At the moment it is not considered economically viable to establish a stationary

crushing plant for high quality recycling and the reuse of pure fractions of

concrete rubble. However, the huge amount of construction waste should be

chrushed and recycled, and illegal tipping avoided, in order to improve the

environment of Sarawak and especially Kuching. Furthermore, the huge amount

of wood waste is a challenge that requires special attention.

68

Literature

Lit. 1: Erik K. Lauritzen

»Demolition and Reuse of Concrete and Masonry: Guidelines for

Demolition and Reuse of Concrete and Masonry«

Proceeding of the Third RILEM International Symposium, Odense 1993

E & FN Spon, 1993

Lit. 2: C. De Pauw, Erik K. Lauritzen

»Disaster Planning, Structural Assessment, Demolition and Recycling«

The RILEM Report No. 9, E & FN Spon, 1994

»Recommendation for Concrete with Recycled Aggregates«

The RILEM Technical Committee TC -121, 1994

Lit. 3: Argus Symonds, PRC Bouwcentrum

»Construction and Demolition Waste Management Practice and Their

Impact« DG XI EU Commission, 2000

Lit. 4: Erik K. Lauritzen

»Economic and Environmental Benefits of Recycling Waste from the

Construction and Demolitions of Buildings« UNEP Industry and

Environment, 1994

Lit. 5: Erik K. Lauritzen, Torben C. Hansen

»Demolition and Recycling 1986-1995« Agency of Environmental

Protection, City of Copenhagen, 1997

Lit. 6: Lisbeth Madsen

»Establishment of a Collection and Treatment System for Construction

and Demolition Waste in Sarawak (Draft)« Sustainable Urban

Development Project, Natural Resources and Environment Board, City

of Kuching, 2001

69

CLOSING THE RURAL-URBAN NUTRIENT CYCLE - NEW TRENDS

IN ORGANIC AND BLACK WATER WASTE MANAGEMENT

Jakob Magid

Department of Agricultural Sciences

Anders Dalsgaard

Department for Veterinary Microbiology

Royal Veterinary and Agricultural University

and

Mogens Henze,

Department for Environmental Science and Engineering,

Danish Technical University

Denmark

In Northern Europe today, water management systems have developed to

maturity without primary concern for recycling. These systems have originally

been designed to ensure a high local hygienic standard. More recently

environmental concerns have been the driving force behind a technological

development of sewage treatment with biological removal of N, P and organic

matter. This technology addresses some immediate problems in the aquatic

environment, but the sewage sludge from the treatment plants contain

considerable quantities of xenobiotic compounds and heavy metals, and only a

fraction of the nutrients that entered the urban areas, thus making the sludge a

non-attractive fertiliser source. In recent years there has been concern about the

sustainability of this state of affairs as regards wastewater handling, as well as

concern about the fate of the final waste deposits in the environment. The

development with respect to solid waste has been different, as the recycling

aspect has been of prominent concern in recent developments.

Recycling of organic waste from the food industry waste has been estimated to

be approximately 99% in Denmark (Danish EPA, 1998) since waste from this

sector is either used for fodder or fertiliser directly or after biogas production.

However the waste management in urban households, service sector and other

industries poses a separate challenge. State of the art systems are based on

collection of solid waste (often separated in an organic and non-organic fraction)

and treatment of wastewater. The sewage systems receives black water

(physiological fraction), grey-water (washing and cleaning), and storm water

runoff. The composition of waste sources from households in Scandinavia

(Table 1) clearly indicates that the urine and faeces fraction contains by far most

of the nutrients in the household waste.

Spokesman for NUTRAP : Centre for Appropriate Technologies for Nutrient Recycling from human

waste to Agriculture in Peri-urban areas

70

Nutrient recycling is not the only consideration with respect to waste handling.

It is important to look at the total waste generation as well as the total waste

handling system. It is important to reach an overall optimal system. There is no

sense in recycling nutrients if handling of other waste streams gives growing

problems. The variability of the wastewater composition that can be obtained

from households where a smaller or bigger part of the Nutrient Rich Household

Waste (NRHW) is removed is show in Table 1. This allows for selection of the

optimal waste technology in the household in combination with optimal

handling of the wastewater. However, the fractionation of the waste streams in

the household is coupled to investments in installations in the buildings.

Table 1 Black, Grey and Light Grey Wastewater Composition

(concentration in g/m3 ). Black Wastewater with and without Urine

Separation. Total Water Consumption Assumed to be 120 l/(cap per day).

Mixed Black Black with

urine sep.

Grey Light grey,

bath + washing

COD 1830 2100 1680 1720 210

BOD 760 690 560 780 100

N 130 340 31 46 23

P 24 53 15 8 6

K 39 99 31 10 6

As seen in Box 1, night soil together with the solid organic household waste

theoretically constitutes 1-1½ % of total liquid household waste volume, but

contains 82-87% of the nutrients. By removing this NRHW the need for nutrient

removal from sewage would be minimal or non-existent.

Further measures to limit the P content of detergents could be taken, if

necessary. In practise systems need to be developed in order to manage this

nutrient rich household waste from urban areas, but a realistic estimate based on

minimal flushing systems indicates the volume of this nutrient rich waste to be

no more than 2-3 m3 person-1 yr-1. In Scandinavia such systems have been

developed and tested for rural areas without sewage systems, and currently trials

with such systems are being made in urban areas. The development of such

systems could have major implications on the environment, public health and

recycling of nutrients to the land.

71

Box 1 Current Household Waste Production / person / yr

In order to address these issues in an integrated way the research centre:

"Centre for Appropriate Technologies for Nutrient Recycling from human waste

to Agriculture in Peri-urban areas" (NUTRAP) was formed.

At present the following Danish Research institutions have signed a

memorandum of understanding on this issue.

The Departments for Agricultural Sciences and Veterinary Microbiology, KVL

The Department for Environment and Resources, DTU and

The National Environmental Research Institute (DMU)

Link to: www.agsci.kvl.dk/nutrap

The urban fertilisers that can be derived from the NRHW fraction compares

favourably to sewage sludge and pig slurry with regard to content of heavy

metals (Table 2). We are currently in the preparatory stage of launching a

programme to assess such urban fertiliser effect on health, environment and

ecosystem integrity. Furthermore NUTRAP has been commissioned to make an

overall assessment of opportunities and barriers for nutrient recycling from

urban areas to peri-urban areas, as well as a technological assessment of

sewerless waste management.

Total volume

(including water for bathing and washing): 57 m3

of which is

Urine: 0.45 m3

Faeces: 0.06 m3

Organic household waste: 0.16 m3

Thus: 85-90 % of the nutrients and much of the organic matter, is contained in

less than 1.5% of the waste volume.

72

Table 2 Average Concentrations of Nutrients and Heavy Metals (mg/kg dry

matter) for Sewage Sludge, Compost, Human Excreta and Pig and Cattle

Slurry. From Eilersen et al. (1998).

Component Sewage

sludge

Compost Human

excretion

Pig slurry Cattle

slurry

Nitrogen 45.000 9.000 130.000 127.000 55.000

Phosphorus 32.000 2.000 20.000 28.000 11.000

Potassium 3.000 3.500 35.000 72.000 50.000

Cadmium 1,5 0,3 0,2 0,5 0,6

Mercury 1,4 0,1 0,7 < 0,1 < 0,1

Lead 57 30 0.3 3 4

Nickel 25 10 1.7 14 8

Chromium 40 10 0.4 10 3

Zinc 775 150 120 1.500 150

Copper 300 50 15 630 65

The optimal waste handling system varies with the location. Factors like

population density, climate, habits, peri-urban agricultural areas, distance to

transport waste, culture and comfort all plays a role when the decision on the

optimal system has to be made. There is not one single solution that is optimal

in general. The local solutions will often need a technological co-actor. Much

local waste handling systems will ultimately have to deposit its waste either to

agricultural land or to centralised treatment plants for wastewater or solid waste.

An integrated framework for assessing the sustainability of wastewater solutions

is outlined in Figure 1 (Eilersen et. al., 1999). The important elements are an

analysis of the local context (on-site analysis), which includes an environmental

analysis and a stakeholder analysis, a listing of alternative technical solutions,

and a multiple-criteria evaluation and prioritisation of the alternatives followed

by the final (political) decision. The on-site analysis and the evaluation will

depend on local and national Environmental policies but the idea is that the

assessment framework should give some feedback to the policy level, eventually

leading to changes of regulations where necessary.

73

Figure 1 Principal Outline of the Assessment Method (Eilersen et. al., 1999)

The multiple-criteria evaluation and prioritisation should be based on

assignation of scores and weighting of criteria in a quantitative manner. It is

simple to make a long list of criteria important to the evaluation of the

sustainability of a given system. However, it is far more complicated to organise

them into independent groups of criteria, avoiding double counting and

overestimation of some and thereby underestimation of others. There is a basic

set of criteria that are relevant for all assessments, e.g. according to the

following list:

Economic: Construction and maintenance costs, and expected lifetime.

Environmental: Pollution; impacts on water, soil and air, and resource

consumption of energy, land, water and materials. Noise and odour problems.

Technical: Robustness and flexibility, adaptability to new demands, new users

and development of new technology. Cleaning- and user-friendliness. Comfort.

Hygienic: Public health and working environment.

Socio-cultural: Transparency and demonstration effect, involvement of users in

the operation of the systems and visibility of local material cycles.

National

EnvironmentalPolicy

Local

Evaluation and order of priorities

EnvironmentalAnalysis

StakeholderAnalysis

On-site Analysis

Start

TechnicalPossibilities

Decision

74

The basic set of criteria will constitute an explicit core of criteria around which a

locally dependent assessment can be created. It is, however, noted that criteria

can be grouped in many other and also meaningful ways, depending on the local

context. The assignment of scores for each criterion is critical, as is the selection

of an appropriate weight for it, relative to the weighting of the other criteria.

Since the criteria cover a wide range of impacts of concern, they will result in

comparisons of dissimilar elements, and weighting of the more qualitatively

criteria will be judgmental. The scoring system must accept both hard and soft

data in a similar format, and the weighting system will be constructed partly by

default values, partly by user modifiable values. The relevant stakeholders can

weight the locally dependent assessment criteria and they may find it necessary

to add extra criteria to ensure that all the significant issues are covered. The per-

formance of the different alternatives for wastewater handling will be compared

to that of a reference condition, a benchmark performance. In summary, the

assessment framework should be transparent, locally based, have a holistic view

on technological choices and finally be robust and flexible.

Part of the data, scorings and weights necessary to evaluate alternatives will be

procured through the on-site analyses, which is divided into analysis

environmental conditions and analysis of stakeholders, cf. Figure 1. An

information tool containing technical information about different handling

options is furthermore necessary to avoid use of misleading information

regarding the technical performance of the many possible technologies. The

following three sections elaborate on these issues.

When implementing new technologies, there is always the risk that they are not

maturely developed. It is important to apply high safety factors/reliance in the

solutions used, in order not to compromise new technologies through failures.

At the same time the technologies must be flexible. The lifetime expectancy of

much waste handling systems is 30-40 years, and many factors might change

before the technology goes to the eternal hunting fields. Possibilities for

stepwise development/construction of new systems are important for their

successful implementation.

Since sewage systems are very costly and often not established in urban areas of

developing countries the above mentioned systems could prove valuable in a DC

context, since it could help in avoiding some of the mistakes that we have done

in our "developed" societies, that have proved so detrimental (or at least not

constructive) to our surroundings. A key element in the recycling of nutrients is

the distance from production of the waste to disposal.

Some examples of recently developed concepts for integrated waste handling in

established urban enclaves vs. undeveloped houses are shown in Figures 2 and

3.

75

Figure 2 A System Diagram for Waste Management in Established Urban

Housing Estates

Figure 3 A System Diagram for Waste Management in New Housing

Estates

Distribution

Recipient

Kithcen

Faeces

Urine

Grey

Treatment plant

Established sewers

Established urban enclave

Biogas from urine, faeces and kitchen waste

Land

Biogas

Truck

TruckTruck Storage tankCollection-

tank

Collection tank Truck

Truck

Storage tank

Storage tank

Distribution

Land

Kitchen

Faeces

Grey

Urine

Undeveloped houses

Biogas from faeces and kitchenwaste - separate handling of urine

Collection-tank

Tankvogn Biogas

SeptictankWillow-, rootzone- or

seepage unit

76

Public health aspects of human waste recycling

The content of this section is based on the Guidelines for the safe use of

wastewater and excreta in agriculture and aquaculture published by the WHO in

collaboration with the UNEP (Mara and Cairncross, 1989).

Human wastes are seen as a resource in several parts of the world where they are

used for a variety of purposes, e.g. wastewater use in agriculture (crop

irrigation); excreta use in agriculture (soil fertilisation); and wastewater and

excreta use in aqua-culture (fish culture, aquatic macrophyte production).

Indirect reuse, the use of water from rivers receiving wastewater effluents, is the

most common process of using effluents not only for irrigation but also,

occasionally after treatment, for potable supplies. In this text "wastewater"

refers to domestic sewage and municipal wastewater that do not contain

substantial quantities of industrial effluent. "Excreta" refers to night soil and to

excreta-derived products such as sludge and septage.

The WHO, FAO, the World Bank and other institutions today recognise that

hygiene standards applied to wastes reuse in the past, based solely on potential

pathogen survival, have been stricter than necessary. Accordingly, guidelines,

based on mainly epidemiological evidence, have been proposed for a more

realistic approach to the use of treated wastewater and excreta (Mara and

Cairncross, 1989). The following summarises the major public health aspects

and health protection measures when recycling human wastes.

In several areas of the world, especially in developing countries, excreta-related

diseases are common, and excreta and wastewater contain correspondingly high

concentrations of excreted pathogens. An understanding of the transmission

routes of such diseases and the health risk factors involved is necessary to

design and implement or modify excreta and wastewater use schemes that do

not result in any increased transmission of excreta-related diseases.

Although a number of excreta-related diseases are of public health importance,

in particular in waste reuse schemes, the reuse of human wastes in agriculture

and aqua-culture can result in an actual risk to public health only if all of the

following occur (Mara and Cairncross, 1989):

a) either an infective dose of an excreted pathogen reaches a field or pond, or

the pathogen multiplies in the field or pond to form an infective dose;

b) the infective dose reaches a human host;

c) the host becomes infected; and

d) the infection causes disease or further transmission. If d) does not occur,

then a), b), and c) can pose only potential risks to public health. Further, if

this sequence of events is broken at any point, the potential risks cannot

77

combine to constitute an actual risk. It is now possible and should be the

aim to design and implement schemes for human waste reuse that pose no

or limited acceptable risks to human health. This requires an understanding

of the epidemiology of the infections in relation to reuse of human wastes.

Subsequently, adequate standards for the microbiological quality of excreta

and wastewater intended for reuse can be established and public health

adequately protected.

Available data from epidemiological studies of wastewater irrigation showed the

following (Mara and Cairncross, 1989): That crop irrigation with untreated

wastewater caused significant excess intestinal nematode infection in crop

consumers and field workers. Especially workers with bare feet have a high risk

of infection, e.g. hookworms. If wastewater is adequately treated, no excess with

intestinal nematode infection was found. Vegetable crops irrigated with

untreated wastewater can effectively transmit cholera, bacillary dysentery, and

probably also typhoid. Cattle grazing on pasture irrigated with raw wastewater

may be infected with the beef tapeworm, but there is little evidence of actual

risks to humans. People living near fields irrigated with raw wastewater is

unlikely to be negatively affected, either directly by contact with the soil or

indirectly by contact with farm workers. Aerosol transmission of excreted

viruses may occur during sprinkler irrigation with treated wastewater. However,

this seems rare in practice because most people have normally high levels of

immunity to endemic viral diseases. It is therefore evident, that if untreated

wastewater is used to irrigate several crops, there is a high actual health risk

from intestinal nematodes and bacteria but little or no risk from viruses.

Accordingly, treatment of wastewater to be used for irrigation is an effective

method of safeguarding public health.

The epidemiological data on excreta use in agriculture show that crop

fertilisation with untreated excreta causes significant excess of intestinal

nematode infection in crop consumers and field workers and may lead to excess

schistosomiasis infection among rice farmers. Excreta treatment can reduce the

transmission of nematode infection.

Very limited data are available about disease transmission associated with

aquacultural use of excreta and wastewater. However, clear epidemiological

evidence exists for the transition of certain trematode diseases.

The following guidelines have been proposed for reuse of treated wastewater:

< 1 viable intestinal nematode egg per litre for restricted or unrestricted

irrigation; and

< 1,000 faecal coliform bacteria per 100 ml for unrestricted irrigation.

Unrestricted irrigation refers to irrigation of trees, fodder and industrial crops,

78

fruit trees and pasture, and restricted irrigation to irrigation of edible crops,

sports fields and public parks.

Socio-cultural aspects of health risks are important determinants in the

transmission of excreta-related diseases, e.g. social preferences and cultural

beliefs of handling human wastes. Thus these aspects must by taken into

account when human wastes are reused.

The technical options for health protection may be divided into four groups:

Treatment of waste: Waste stabilisation ponds, disinfection, excreta (eg. heat)

treatment (composting).

Crop restriction: Crop restriction provides protection to consumers but not to

farm workers and their families. Thus, other measures like partial waste

treatment, controlled waste application and human exposure control are needed

to protect the health of farm workers.

Application of wastewater and excreta: Means of application by flooding,

furrows, sprinklers, subsurface irrigation and by localised (trickle, drip or

bubbler) irrigation of which each represent different risks to human health.

Human exposure control: Four groups of people can be identified as being at

potential risk from the agricultural use of wastewater and excreta: a) agricultural

field workers and their families; b) crop handlers; c) consumers (of crops, meat

and milk), and d) those living near the affected fields.

Although some data are available of health risks associated with the reuse of

human wastes, additional research into a number of areas related to human

health is needed to provide support to improve existing use practices, not only to

minimise health risks but also to increase productivity. Similar research is

needed of the health impact of new reuse technologies. Although the use of

human wastes for crop and fish production often takes place illegally and

without official recognition by the responsible authorities, banning the practice

is unlikely to reduce either its prevalence or the public health risk involved, and

may make it more difficult than ever to supervise and control.

ACTIVITIES IN NUTRAP

Currently NUTRAP‟s activities are mainly limited to Denmark, but we are

considering possibilities for collaboration internationally.

79

Literature

Lit. 1: Danish EPA

»Organiske Restprodukter i Industrien, Opgørelse af Mængder og

Anvendelse« Miljøstyrelsen, Ferskvands - og spildevandskontoret.

København, 1998

Lit. 2: A. Eilersen, Jakob Magid, J.C. Tjell

»Anvendelse af Affaldsprodukter på Jord« In Affaldsteknologi, Ed. Th.

Christensen, pp. 493-510, Teknisk Forlag, City of Copenhagen, 1998

Lit. 3: Ann Marie Eilersen, Susanne Balslev Nielsen, Søren Gabriel, Birgitte

Hoffmann, Claus Rehfeld Moshøj, Mogens Henze, Morten Elle, Peter

Steen Mikkelsen

»Accessing the Sustainability of Wastewater Handling in Non-sewered

Settlements« Department of Environmental Science and Engineering,

Technical University of Denmark, 1999

Lit. 4: D. Mara, S. Cairncross

»Guidelines for the Safe Use of Wastewater and Excreta in Agriculture

and Aquaculture« pg. 187, World Health Organisation, 1989