assesing the sw tech

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ASSESSING THE FEASIBILITY OF A SOLID WASTE TREATMENT DISPOSAL

SCENARIO IN THE DEVELOPING COUNTRIES

MAVROPOULOS A.1, KARKAZI A.21

EPEM, Head of Solid Waste Management Department2EPEM, Chief Engineer of Solid Waste Management Department

Averof 34A str., 142 32 N. Ionia, Athens, Greece, [email protected]

SUMMARY

Last ten years are characterized by the rapid expansion of the available solid waste

(SW) treatment and disposal technologies. Gasification, thermolysis, anaerobic digestion and

a lot of other proven (and sometimes not proven) technologies are now available for the SW

treatment or/and disposal. At the same time the traditional technologies (landfill, incineration

and composting) are getting much more complicated and environmentally sound. The aim of

this paper is to outline a generalized methodology that can help the decision-makers indeveloping countries to answer the following question: How to select the appropriate

technology for the SW treatment and disposal? The main idea is to use profiles and screening

techniques for the reduction of the alternatives and to set some well-defined criteria in order

to assess the feasibility of each technology (or of each combination of technologies). This

methodology can provide a basis for the necessary strategic approach of SW treatment and

disposal planning. The utilization of this methodology can help developing countries to save

money and decision-makers to save time.

1. BACKGROUND

In most of the developing countries and their metropolitan areas SW is at best

collected and dumped outside the cities or at worst partially collected and dumped out of the

sight. Although there are a lot of significant efforts in strategic planning (1),(2), important case

studies (3) and numerous small scale successful experiments (4), the problem of Solid Waste

Management in developing countries remains a major environmental and social-economical

problem. There are a lot of reasons that can explain this situation and undoubtedly the main

reason is the lack of financial resources. The lack of institutional development (5) and the

absence of a systematic strategic approach to the problem (6)are important reasons, too. There

is also another reason which becomes from the fact that a lot of plans have been failed

because they tried to face the SWM problem in developing countries within the framework

that has been formulated in developed and industrialized countries. This paper predicates that

the current scientific SWM tools are not in a position to face SWM in low-income countriesin a successful way, at least about treatment and disposal of waste. And this is due to the

particularities that characterize the SWM science development.

The SWM science is a relatively new field in the history of sciences. Concerning only

the treatment and disposal part of SWM science, it is no more than 50-60 years since the

problem of SW disposal was recognized as a problem that needs not only a systematic

approach but also scientific research. The treatment and disposal phase has also some

particularities such:

The social pressure that usually exists and makes each problem much more

difficult.

The direct relationship with the social and economical level.

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The relative uncertainty that characterizes the available experimental data,

especially for the long-term behavior of the complicated physico-chemical systems

that are found in disposal facilities.

The difficulty that exist in order to determine the exact environmental impacts,

especially in the cases where the impacts are not local (e.g. incineration or landfill

air emissions).

Especially for the developing countries there are two more major particularities that

make the SWM problems more complicated. First of all the main progress in SWM science

comes from developed countries where there is a completely different situation at all the

related parameters, including quantities and composition of waste, institutional building,

available financial resources, legislative framework etc. Secondly, in most of the developing

countries the solution in SWM problems seems to be a luxury choice when there are some

much more urgent problems to be solved as extended poverty, lack of fresh water etc.

The aim of this paper is to outline a generalized methodology that can help the

decision-makers in developing countries (and not only) to answer the question: How to select

the appropriate technology for the SW treatment and disposal? The answer to this question

becomes critical since there are numerous alternatives available.

1. NEW PRODUCTS AND THE DEMAND FOR NEW SCIENTIFIC TOOLS

Last ten years are characterized by the rapid expansion of the available SW treatment

and disposal technologies. Gasification, thermolysis, anaerobic digestion and a lot of other

proven (and sometimes not proven) technologies are now available for the SW treatment

or/and disposal. At the same time the traditional technologies (landfill, incineration and

composting) are getting much more complicated and environmentally sound. So the problem

of the selection of the appropriate treatment and disposal scenario for each case becomes avery difficult problem, without a simple or single solution. There are three causes that make

the problem very difficult:

The arising investment and operational cost that characterizes the new alternative

treatment solutions, especially them those seem to be more environmental sound.

The fact that a lot of the pronounced technologies are developed inside the

laboratories of big waste companies and so the access to real data about their

products is practically impossible.

The lack of generally accepted scientific methodologies that can be used in order

to evaluate the feasibility of each treatment and disposal technology.

In the framework of globalization, the problem is getting much more complicated indeveloping countries by the fact that their market is usually a major target for big waste

industry. A lot of such companies promote their products in a way that makes impossible the

understanding of their real value and sometimes they seem to have some kind of magic and

non cost solutions that makes them very attractive.

As a matter of fact a lot of alternative solutions do exist and the technologies

developers can provide a lot of (usually advertising) information about their products. But it

seems that the more information they provide the more difficult is the selection between

different products. There is an urgent need for the development of scientific evaluation tools

and methodologies that will provide a way to compare the available technologies and at the

same time they will help the decision making process.

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The choice of the appropriate treatment and disposal technology is not a pure

technical issue; it is much more concerned with the financial resources and the organization

and management of relationships between all of the key actors or stakeholders(6). So it must

be faced as an interactive process for all the involved parts that scopes to find affordable

solutions in a strategic view. In fact there is a rule of thumb: every step that is done must be

well connected with the possible next steps or in reverse no step must be done if it is notcorrelated with the whole strategic planning.

Another useful remark is that when someone has to decide about the treatment and

disposal technologies, emphasis must be given to Whole and not to Part. It is always valuable

to remember that protection of the Environment can only become as a result of a systems

approach where the whole problem is faced(7). Therefore decision-makers should keep in

mind the Comparative Principle(8): All the actions that require expenditures of resources must

be justified in the context of opportunity cost, i.e. the potential of achieving the same goals

more efficiently in doing something else.

The methodology that will be presented can help at the formulation of affordablestrategic solutions and also can be used for the evaluation of strategic plans and treatment and

disposal proposals. More specifically, the proposed methodology can be utilized in two

different cases:

When someone has to evaluate the feasibility of a proposed SW treatment and/or

disposal scenario.

When someone has to compare different SW treatment and/or disposal scenarios.

The proposed methodology consists of the following steps:

PHASE 1

1. CREATE A PROFILE OF THE EXAMINED AREA2. CREATE A PROFILE FOR THE EXAMINED TECHNOLOGIES

3. CREATE A PROFILE FOR THE PRODUCTS OF EACH TECHNOLOGY

SCREENING

PHASE 2

4. CREATION OF COMPLETED SCENARIOS

5. EVALUATION CRITERIA

6. COST BENEFIT ANALYSIS

2. CREATING PROFILES AND SCREENING

The first step should always be an extended inventory of the existing situation. An

agreement on this point is something very common but what is not common is the creation ofdetailed studies about the existing situation. This is one usual mistake because a detailed

study about the existing situation can help:

To define the opportunities for improvements

To identify the barriers or the constraints of the situation

To determine the necessary steps forward

A detailed study for the existing situation can also provide very useful information

about the main problems that have been raised due to waste mismanagement and so it can

help to assess the cost of waste mismanagement (9). This is always the first key point in order

to build an efficient waste management system.

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The profile of the examined area (with the assumption that this area is already

defined) is created, at least, from the elements that are presented in Table 1.

Table 1: Minimum data for the profile of the examined area

MINIMUM ELEMENTS COMMENTS

Problems due to waste mismanagement Key point for the proposed solutions

SW amount trends spatial distribution

SW composition trends It concerns all kinds of SW

Seasonal variations

Estimate combustible fraction

Estimate recyclable fraction Basis for the feasibility estimation

Estimate organic fraction

Estimate inert fractionExisting facilities See if there are some that can be utilized

Current collection and transfer cost Basis for comparison with future cost

Current treatment and disposal cost Basis for comparison with future cost

Main economic activities Basis for the outline of treatment product

Trends for economic development Basis for setting an upper limit for SWM cost

Trends for social development Basis for determination of education -

sensitization awareness measuresAuthorities that are involved in SWM Basis for the future institutional development

market

The next step is the creation of the examined technologies profile(10). This profile

consists of the answers to the questions of Table 2.

Table 2: Critical questions for the formulation of a technology profile

1. Is the technology proven?

2. Is there a reference list with similar facilities?

3. Which is the most suitable waste?

4. What types of waste can be accepted?5. What are the mechanical, physical and chemical processes of the waste treatment?

6. Which are the residues and the by- products of each separate process?

7. Which is the composition of the residues and how can they be managed?

8. Which are the end products of the whole process?

9. Which are the possible markets for end products?

10. Which will be the added value by the use of the specific technology?

11. Which is the investment cost?

12. Which is the net operational cost per ton of processed waste?

At this point some comments must be mentioned about the available technologies.

Since wastes do exist, there is no magic treatment and disposal solution. Every solution has asignificant environmental and economic cost. Therefore it is obvious that waste prevention is

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the first principle in an integrated approach to SWM. But things are much more complicated

when someone has to decide for treatment and disposal solutions. It must be underlined that

when only proven and reliable technologies (or combinations of them) are concerned, no

alternative is out of discussion as an environmental disaster. On the other hand, no

alternative is in principle preferable as the environmental saver. No environmental disasters

no environmental savers, everything must be examined in detail and a comparative analysisshould be implemented point by point. But before the comparative analysis, there are two, at

least, screening processes that help to save time and money. If the examined technologies

produce some kind of useful end products, then a screening process should be about the

product disposition and the possible markets for them. A profile of the end products can be

very helpful for this process. Table 3 shows some relevant questions that have to be

answered.

Table 3: Critical questions for the formulation of the end product profile

Which are the possible uses of the product?

Is there a proven experience by the use of the product?

Which are the specifications of the product (composition, form etc.)?Are there suitable markets or potential users for the product in the examined area?

Is there an opportunity of transferring the product somewhere else?

Which is the total market capacity for the product?

Who will undertake the delivery of the product?

Which could be the lower price for the products?

Is the product disposition guaranteed?

A good approach for screening is to cut the technologies that create products that

cannot be undertaken from market and potential users, under the specific local conditions

(taking into account not only the current situation but also the future trends). Of course,sometimes products may not be easily delivered at first but if they prove their helpfulness

they may become popular. At these cases, a pilot application is the only way to test the

market conditions.

There is also another preliminary screening process that can be used depending on the

availability of the required information. This screening is only indicative and concerns the

lower quantities that are necessary for the reliable operation of a waste treatment and/or

disposal facility(11). This lower limit is considered as a technical and economical limit for the

feasibility of each proven technology. Under this limit, the operation of a facility is much

more expensive or less efficient. Also this limit is depended on the evolution of waste

treatment and/or disposal processes and that means that every time someone wants to set suchlimits he is obliged to make a market research for the available products. The limits of Table

4 were proposed in Greek islands in 1997(10)(11).

Table 4: Suggested lower limits for selected technologies

TECHNOLOGY LOWER LIMIT

Mechanical separation composting 9.000 tons of organic waste/year

Anaerobic digestion* - energy recovery - 9.000 tons of organic waste/year

Incineration without energy recovery** 14.000 tons of combustible waste/year

Incineration with energy recovery** 28.000 tons of combustible waste/year

composting

*: Including organic separation process

**: Concerns continuous operation of the incinerator and full air emission control.

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The use of such limits means that i.e. if the examined area produces less than 28.000

tons of combustible wastes per year, then the incineration with energy recovery is not

suggested. Therefore, the use of these limits can help to reduce the alternatives that should be

examined in detail.

Sometimes, even if someone applies the two previous screening processes, there are alot of alternatives that should be examined in detail. So it may be useful to set another

screening process that is based on the affordable cost. The definition of what is affordable

and what is not is something very difficult but, generally, there are some ways to approach

it. As an example, someone can put the question: If the current SWM cost (per capita or per

ton) is X, which is the upper limit that it can become in the next 5 years? The more detailed is

the profile of the examined area (see Table 1) the more successful will be the approach to the

real answer (taking into account all the relevant parameters). Having an idea of the answer or

setting some prices as an upper limit every technology that results in a non-affordable cost

(over the limit) should be excluded. This way someone can use this limit to reduce more the

alternatives that should be further examined.

3. COMPARATIVE ANALYSIS

Until this point there was no need for the creation of detailed scenarios for each

technology. At the first phase the judgement about the feasibility of the technologies was

based at some general characteristics of them. Since there are technologies that have

successfully passed the first phase, there is a need for comparative analysis and that means

creation of completed scenarios for each technology. Table 5 shows some critical points that

must be included in a scenario development.

Table 5: Critical points for a scenario development

CRITICAL POINTS COMMENTS

Estimation of waste input in details For every waste stream, including seasonal

variations

Mass and energy balances For the whole process, including energy and

resources consumption if needed

Estimation of the residues and emissions For the whole process

Estimation of useful end products For every product, including composition and

quality projections

Estimation of environmental impacts With quantification where is possible

Description of all the operational needs

and practices of the facility

I.e. personnel, energy and resources consumption,

maintenance etc.

Estimation of the required investment

cost

Alternative ways of financing should be

Estimation of the net operational cost per

capita and /or per ton

Without the potential input of income from the

end products sales

Estimation of the transfer cost Necessary for the estimation of feasibility

Estimation of the potential input from the

end products sales

Without overestimation of the inputs and with the

examined

seasonal variation

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No scenario must be developed without landfills because landfills are necessary as the

final disposal option - or the no alternative option - in every system. There are also cases

where the application of specific technologies produces hazardous waste in small amounts

and then a hazardous waste landfill is necessary. A good suggestion is to start the

development of the treatment - disposal facilities always with the necessary landfills; this is

an always-successful first step. Although it can not be a long-term solution, sometimes theupgrade of existing dumps to sanitary landfills is also a good first step.

It must be noticed that the creation of the scenarios should always be in accordance

with the criteria that will be used in order to evaluate the scenarios. So if the criteria are not

clearly defined, some times is better to start with the definition of the evaluation criteria.

Another important remark is that a lot of times scenarios do not include proposals or

determination of the institutional management of the new facilities. The questions Who will

have the responsibility for the transfer of waste to the facility? and Who will have the

responsibility for the facility operation? must always be answered and the answers should be

evaluated.

After the development of the scenarios, their evaluation needs a well-defined set of

criteria. There are a lot of multicriteria systems that can be utilized for an integrated

comparison. Such a system is presented in Table 6 (11).

Table 6: A proposed multicriteria system for the comparison of scenarios

CRITERIA GROUPS CRITERIA

SOCIAL CRITERIA Accordance with the legislation status

Social acceptance

ENVIRONMENTAL CRITERIA Non reversed environmental impacts Long term effects at Human Health

Contribution to green-house effect and acid-rain

Odor emissions and control

Waste water production and control

Solid residues production and control

Land consumption

Noise pollution

Aesthetic pollution

Material recovery

Energy recovery

Waste Volume ReductionECONOMIC CRITERIA Investment cost

Way of financing

Operational cost without income from product sales

Compatibility with the trends of social-economical

Estimated income from product sales

TECHNICAL CRITERIA Flexibility adaptation to seasonal variations

Operational needs

Reliability reference list

development

Every waste treatment and disposal scenario transforms the pollution form from SW

to air pollution, wastewater, solid residues or sludge. So sometimes is very useful to think

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that the comparison of the environmental impacts of different scenarios is, in truth,

comparison between different forms of pollution and the real problems are:

Which form is more appropriate to local conditions?

Which form seems to be easier to manage?

The result of the comparison must be completed with the detailed analysis of theexpected results from the application of the best scenario. At this point, the only question that

remains is more a political and less a technical question: Are the expected benefits enough

for the required cost?. Anyway, a cost benefit analysis should always follow the results of

the scenario comparison.

4. CONCLUSIONS

The multiplication of the available SW treatment and/or disposal technologies creates

a demand for new scientific evaluation tools. Due to some general characteristics of the

SWM science, the selection of the appropriate treatment and/or disposal technology in

developing countries seems much more difficult.

The methodology consists of two phases, a preliminary screening phase and a detailed

scenario comparison phase. Emphasis is given at the detailed inventory of the existing

situation, which is the main presupposition for the success of the whole process. The creation

of profiles for the examined technologies and the possible products is of major importance

and then a preliminary screening comes to reduce the number of alternatives.

Screening can be implemented with the product disposition or with the lower capacity

limit or with the upper cost for each technology or with a combination of them. Finally, a

detailed scenario development and comparison comes to complete the whole process. For the

selected technology it should always be a cost benefit analysis.

The presented methodology can be utilized at the formulation of affordable strategic

solutions and also can be used for the evaluation of strategic plans and treatment and disposalproposals. It can help decision-makers to save time and developing countries to save money.

It can also help to better exploitation of the limited financial resources.

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REFERENCES

(1) C. Simon, J. Phatshwe Botswanas Waste: The challenges and Successes, Proceedings

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Vol. V, p. 95

(2) T. Loumbert, L. Bredenhann, J. Borland, H. Wiechers Development of a National WasteManagement Strategy for South Africa, Proceedings of Seventh International Waste

Management and Landfill Symposium, Sardinia 1999,Vol. V, p. 49

(3) L. Iskandar Kamel MSW Management: Local Knowledge and National Development. A

case study from Egypt, Proceedings of Seventh International Waste Management and

Landfill Symposium, Sardinia 1999, Vol. V, p. 113

(4) Workshop report Micro and small enterprises involvement in municipal solid waste

management in developing countries, UMP/SDC Collaborative program, Cairo, Egypt

1996

(5) D.J.V. Campbell Institutional development for waste management in developing

countries, Waste Research and Management, Vol. 17, No. 1, February 1999.

(6) Urban Development Division of World Bank Planning Guide for Strategic MunicipalSolid Waste Management in Major Cities in Low Income Countries, 1998

(7) Panagiotakopoulos D. A Mediterranean view to the Sanitary Landfill Design for

Municipal Solid Waste, Alexandria, RETBE 1996

(8) Zandi I. Major issues facing Solid Waste Management in the 1990s, Journal of

Resource Management and Technology, vol. 19, No 4, 1991

(9) I. A. Paris. The cost of Waste Mismanagement ISWA TIMES , No. 2, 1999

(10) Mavropoulos A., Loizidou M., Loukatos A. A managerial tool for the SWM in

Greek Islands, Pyrforos, NTUA, vol. 2, October 1999

(11) NTUA, Chem. Eng. Dept. Research program for the evaluation of the available solid

waste treatment and disposal technologies and application at the Aegean Sea islands,

Athens, 1997.

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assesing the sw tech

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