Solid Waste Management in
Emerging Industrialised Countries

By Chandran Nair
September 1993

The Author is Managing Director of Environmental Resources Management in Hong Kong. ERM is a full-service environmental consulting group with offices worldwide.

Contents

  1. Introduction
  2. Why Solid Waste Management is a Priority?
  3. The Need to Adapt Western Technologies and Management Systems
  4. Solid Waste Storage and Collection
  5. Recycling
  6. Solid Waste Treatment and Disposal
  7. Public Versus Private Sector Operation
  8. Hazardous and Other Special Wastes

1. Introduction

Solid waste management is an integral part of public health and environmental control, being of particular importance in highly populated urban areas.

Over the last twenty years, waste management has begun to emerge in developed countries as a scientific and engineering profession in its own right. Environmental standards of refuse incineration and landfilling have gradually improved, and new methods of refuse sorting and resource recovery have begun to emerge. Research has been directed, for example, at the behaviour of waste in landfill sites, focusing particularly on the production of leachate and its potential for water pollution. Industrial, and in particular hazardous wastes, have emerged as a priority concern. With complex legislation and control systems, and networks of sophisticated treatment and disposal facilities, being developed in parallel. The political priority given to waste management has increased sharply, largely due to public concern over well publicised incidents.

In the developing world, individual countries are at various stages in this gradual evolution towards "modern" standards of waste management. In many of the poorest countries, and in the low income areas of major cities such as Bangkok and Manila, the first priority is still to get the refuse out from under the roof. The standards of waste disposal are still almost universally low, with open dumping as the standard method in most countries. Hazardous wastes are beginning to be recognised as a priority problem, but most countries are at a relatively early stage in developing and implementing action programmes.

The experience of the last fifty years in developed countries is highly relevant to Asia countries as they continue to tackle solid waste management problems. By examining both the successes and failures of past programmes in developed countries, it should be possible to benefit from the experiences of others. However, it must be recognised that the priorities of the 1990´s in emerging industrialised countries (EIC) are likely to be very different from those in developed countries. When your level of control has reached, say 90%, your aim is to approach 99%; whereas if your level of control is only 30%, then you will be fairly ambitious to adopt 90% as your goal. In addition, technologies and management systems from developed countries will not necessarily achieve their purpose in EIC´s, on the contrary they will almost always require adapting to become more appropriate to the specific problems and needs of each particular country.

2. Why Solid Waste Management is a Priority?

An essential prerequisite for any successful programme to improve solid waste management is to establish it as a political priority. This was achieved in industrialised countries largely through a recognition of the public health and environmental consequences of inadequate management practices. They may be categorised into five major aspects:

3. The Need to Adapt Western Technologies and Management Systems

Technologies and management systems which are used in developed countries need to be adapted to the local situation in any particular EIC. These reasons may be grouped under four categories:

3.1 The Nature of the Waste

The nature of the waste may be conveniently considered under five headings:

Waste Generation Rates
Measurement of waste generation rates in EIC´s is both uncommon and difficult. Waste generation rates are often quoted in the range 1 - 2 kg per capita per day in developed countries and perhaps 0.4 - 0.8 kg per capita per day in EIC´s or developing countries. However, there is no substitute for local measurement.

Waste Density
As with all other data, density values from municipal solid waste vary widely. However, as a generalisation, waste tends to have a lower density in industrialised countries than in Asia, due to the predominance of non-putrescible components such as paper, plastics and other packaging materials. Typical densities of waste as collected in north America or Europe are in the range of 100 - 150 kg/m³. Densities tend to be higher at communal collection points, due to self compaction.

Waste Composition
Again, refuse composition varies enormously, both between locations in the same country, and also from season to season and even from day to day. "Typical" values for industrialised, middle income and low income countries are shown in Figure 1. Of particular importance is the content of vegetable and putrescible matter, which is typically in the range of 20 - 24% in industrialised countries and 40 - 80% in low income developing countries.

Moisture Content
The moisture content of waste is most directly related to the putrescible content, so that it is lowest in industrialised countries (20 - 30%), and highest in low income developing countries (40 - 80%).

Size Distribution of Waste Materials
The average particle size of solid waste in developing countries tends to be significantly smaller than in industrialised countries. This means, for example, that many modern mechanised methods for resource recovery from developed countries, which rely on size reduction as a preliminary step, are often inappropriate in Asia.

Figure 1

3.2 Climate and Geographical Situation

The geographical setting of a city is important in designing an appropriate waste management system. Many cities in Asia are categorised by:

One direct consequence of the combination of a hot climate, limited storage space in living premises and a high putrescible content of the refuse, is that the collection frequency for municipal solid waste in densely populated areas in Asian cities is often every day, or at most every other day, whereas in many industrialised countries frequencies of one or two times a week are considered adequate to control odours and public health risks.

3.3 Institutional Constraints

Many solid waste planning efforts in developing countries have emphasised technology at the expense of management support systems. This has unfortunately been due to a lack of understanding of the policy issues related to effective waste management strategies and a lack of experience in implementing programmes. This in turn is due to institutional weakness and unfortunately the involvement of politics. An acceptable level of service for waste management depends critically on well planned management, operating within an adequate institutional arrangement and capable of generating the financial resources required to meet operating maintenance and investment costs.

Among the common weaknesses in existing institutional systems are untrained staff, poor pay scales, the lack of incentives to do a good job, and corruption. Related to these are two key problem areas, namely inadequate supervision of workers and inadequate maintenance of facilities. In industrialised countries, one would expect one supervisor for every five to seven collection vehicles, whereas one per 10 - 30 vehicles is more common in Asia. In addition, supervisors in Asia often have no means of moving about within their service area, so that effective supervision is very difficult.

In many cities in Asia, the solid waste management service is by far the largest employer of labour and user of transport, and spends the largest proportion of the revenue budget of the city, and yet it is relatively uncommon to find at senior management level an individual officer with direct line management responsibility for all aspects of solid waste management operations. There is often a small Cleansing Department at City Hall, with all labourers and supervisors managed on a decentralised basis in city districts. Often there is no planning unit, and the operational records which are essential to monitor and improve performance of the service are often poor or even non-existent.

The provision of adequate funding for solid waste management on an ongoing basis is a major problem in many Asia cities. As the proportion of total city budget which is spent on cleansing may be quite large, this implies an effort to improve the overall municipal administration system. This is because the money for running the service most commonly comes from the general municipal revenue. Direct user charges for refuse services are relatively uncommon, and where they do exist, collection rates are often very low. Three particular problems with direct charges are that those who can afford to pay live in the better income areas, while the problem is often providing an adequate service in the poorer areas; there is usually no viable means of shutting off service to a resident who doesn´t pay his/her bills; and a direct charge provides an incentive to indiscriminate dumping, which is the opposite effect to that intended.

The objective in solid waste management in Asia can often be summarised as to provide adequate and affordable service, through the use of least cost, viable techniques. However, the objective of minimum cost must be subjected to a number of constraints, so that employment objectives, the real cost of imports and limitations on capital expenditure are also taken into account. Also of importance in planning capital expenditure are possible shortages of skilled labour for operation and maintenance, and the availability and affordability of spare parts.

3.4 Differences Specific to Hazardous Waste

In considering the need to adapt hazardous waste management methods from developed countries to the specific local needs and circumstances of Asia, some of the above factors are important. For example:

One difference which can be turned to an advantage is that many Asian countries are actively encouraging new industry. Most countries have a licensing system for new factories: this should be extended to include explicit provision for industrial and hazardous waste minimisation, recycling, treatment and, as a last resort, proper disposal. An attractive option is to provide industrial estates for particular types of waste producing industry, eg. electronics, where the provision of centralised waste treatment facilities at an economic (shared) cost could be a positive factor in encouraging investment.

4. Solid Waste Storage and Collection

As stated earlier, the first priority in many Asian cities is literally to get the refuse out from under the foot. In cities such as Bangkok and Manila, estimates of uncollected solid waste are around 20 - 30%. Uncollected refuse provides breeding ground for disease vectors, both directly and indirectly through blocking surface drains. The lowest level of service is inevitably in the slum and shanty neighbourhoods, where access is poor.

The question of the selection of appropriate technology and management systems for refuse storage and collection is also an important one. The factors which must be taken into account include the following:

Experience in a number of Asian countries has shown that simple changes in collection systems, using indigenous, low cost and easily maintainable equipment, can provide an improved service to a much higher proportion of the population than before at no increase in cost.

5. Recycling

Recycling systems are often well established in Asian cities. Figure 2 is a typical schematic representation of recycling systems in Asian cities.

Figure 2

Although the health conditions of scavengers living on open dumps are obviously poor, it is not possible to dismiss the current informal recycling systems. Many people choose to work as scavengers on the dump sites rather than in factories; unemployment is high, so the value of jobs to the economy is considerable; the level of income from scavenging is competitive with that from other forms of employment, and indeed refuse collectors in Bangkok often more than double their income through scavenging; and the savings in both raw materials and energy costs through recycling make an important contribution to many national economies.

When living standards and household incomes reach the level of Singapore, then a prohibition on scavenging may be both justifiable and implementable. However, in most Asian cities, the informal recycling sector is currently making an important contribution to the national economy and the environment. At least in the short term, an appropriate and sustainable solution to the solid waste problem needs to build on; rather than undermine; the existing recycling system.

One possibility is to increase the proportion of waste which is separated at source by the householder, employing more scavengers in the initial stage of collecting separated materials from door to door. The ability to pay householders for these separated items gives the possibility for much higher participation rates than those achieved in industrialised countries for such "source separation" schemes. However, lack of space in households for storage of separated refuse, even with frequent collection, may well prove to be a major constraint. Nevertheless, pilot schemes along these lines are to be encouraged. One Advantage of source separation over any of the other alternatives is the possibility of separating a clean organic fraction, to serve as an input to composting.

A number of studies have examined the potential for increasing the effectiveness of recycling through a combination of manual and mechanical sorting. For example, an early study carried out by ERM in Bangkok showed that such a low technology approach, utilising the skills of the scavenger community, could increase materials recovery from the refuse (excluding the initial separation at source) from around 7% to about 16% by weight. In addition to the sorted materials, such a sorting plant would produce an organic rich fraction for composting and a residual stream with potential for use as a refuse derived fuel. One of the major attractions of such a system is that revenue is being generated from the waste, so that the potential exists for attracting local private sector investment into the solid waste system.

6. Solid Waste Treatment and Disposal

6.1 Landfilling

The present disposal method for solid waste in most Asian cities is generally open dumping, with associated water pollution and public health problems. Upgrading open dumps into properly managed, environmentally acceptable landfill sites must be the first priority. However, this can be very difficult in practice, due for example to the lack of suitable sites, potential water pollution problems, shortages of cover material and the presence of scavenger communities who depend for their livelihood on the waste.

An urgent need in Asian countries is for demonstration projects, to show that upgrading of existing dumps into (partially controlled) landfills is possible, and that establishment of properly controlled new landfill sites is feasible. The need for such demonstration is due both to the technical problems, for example, preventing water pollution, and also to the institutional problems of gaining public acceptance for new sites and displacing scavenger communities.

The difficulties in achieving proper landfill standards, particularly in respect of water pollution control, should not be underestimated. However, considerable improvements over current open dumping practices can be made at relatively low cost. Proper sites selection should avoid at least the most unsuitable sites, which often seem to be used at the moment. Proper management of the site, and in particular cellular methods of operation whereby the waste is brought to its final level in one area as quickly as possible, rather than being spread in a thin layer over all of the site, will decrease the amount of rainwater being transformed into contaminated leachate. Shortage of cover material may make it difficult to cover the waste every day, but the relatively small particle size of waste in Asia as opposed to industrialised countries, together with the possibility of making cover material through composting the organic fraction of the waste, should make this problem manageable. Adequate compaction of the waste to eliminate void spaces and discourage rats and other vermin should be possible without the use of sophisticated landfill compactors as used in developed countries.

6.2 Incineration and Composting

Traditional aid-funded solutions for solid waste disposal have often based on the export of western technology, either incineration or composting. In many cities, the moisture content of the refuse is too high to burn without the addition of expensive support fuel, unless stringent measures are taken to prevent the recycling of paper and plastics. In many instances recycling is a preferable method of waste management to waste treatment, so that any such prohibition would be a retrograde step.

Given the extremely high capital cost of incineration, the requirement for skilled labour both for operation and maintenance, and the high cost of imported spare parts, the potential for incineration in Asia is limited in the near future, outside of special situations such as that in Singapore, Hong Kong, Taiwan and of particular specialist applications such as for clinical wastes and other selected hazardous wastes.

Composting can be promising as a waste management option, on account of the high organic content of refuse in Asia. However, many projects have failed on account of the high sophistication of the plant, leading to difficulties with operation and maintenance. In addition, the use of pulverisers for size reduction has resulted in a compost product which is contaminated with both finely ground glass and small pieces of plastic. Even without concerns about contamination with heavy metals (originating both from batteries and also from urban air pollution), the obvious presence of these contrary materials in the compost have made it extremely difficult to market in many countries.

6.3 Intermediate Technologies

Intermediate technology approaches to refuse treatment and disposal are possible.

Separation of a clean organic fraction for composting, either from such a plant or at source, could feed directly into a series of simple facilities to produce compost using the traditional windrow system. This would eliminate the need for sophisticated imported technology and could also provide a valuable plant growth medium where the local soil lacks organic content.

A clean organic fraction separated from solid waste could also be used as a feedstock for anaerobic digestion, producing biogas. Indeed, a landfill site may be viewed under favourable circumstances as the simplest form of such a digester. While this idea has certain attractions, and could qualify as "intermediate technology", experience in industrialised countries has thus far not been particularly positive.

7. Public Versus Private Sector Operation

Collection and disposal of solid waste within an urban area has traditionally been perceived as the responsibility of the local municipal government. Provision of services to collect and dispose of municipal refuse is expensive, even when the most primitive methods are employed. It is not unusual for the cost to comprise 20-40% of a municipal budget. Collection and transportation generally make up 70-80% of these amounts, with disposal comprising the remainder.

In industrialised countries, it is becoming more common for the private sector to become involved in refuse collection and disposal. In Europe, the service is still the responsibility of the local government, who contract out its operation to the private sector. The local government collect the appropriate fees and supervise the standard of service provision. In the US, the private sector works directly to the householder, collecting a user fee indirectly. In both Europe and the US, industrial waste services are provided direct to industry by the private sector.

It is of interest here to add the "Hong Kong model". Three refuse transfer stations, two strategic landfills, and a centralised hazardous waste treatment service (including collection and treatment) have so far been "privatised". The Hong Kong Government retains responsibility, but has contracted out detailed design, construction and the first 15 years of facility operation to the private sector.

There is currently considerable interest in the potential for introducing the private sector to solid waste management services in Asia. While this has some potential for cost saving, it is certainly not a panacea to solve all problems. Two particular pitfalls need to be avoided.

The first of these is that a direct service, where a householder pays the waste collector directly, would tend to serve mainly the middle and upper income levels, as low income people could not afford the expense. Similarly, if the private collectors are performing the service in order to make a profit from the recyclable, they would again tend to serve only those residents with "rich" waste. In either case, a substantial proportion of the city´s refuse would be left uncollected; it may be inefficient for the City to collect the leftovers of the primary private sector system.

A more appropriate model of private sector involvement might well be the "European" or Hong Kong" system, whereby collection and/or disposal is contracted out by the public sector to the private sector, with responsibility for funding and for monitoring the quality of the service remaining with the public sector.

The pitfall to avoid here is that of accepting the lowest bid irrespective of the standard of service to be provided. The majority of the problems could be satisfactorily resolved if a number of deficiencies in the contract or the contracting system were resolved. These include:

8. Hazardous and Other Special Wastes

Hazardous waste management in Asia has received increasing attention from international and other organisations over the last ten years, but it is still not high on the political agenda in many countries.

Much recent publicity has been given to attempts to export hazardous waste from developed to developing countries. The publications cited show that Asian countries also need to develop control systems to deal with their own hazardous wastes being generated within the country. In the absence of such systems, hazardous wastes are currently being disposed of in an uncontrolled manner, either on the land or to watercourses. Short term public health risks may ensue through pollution of water supplies used for drinking or for irrigation, or to scavengers who work on open dumps. In the longer term, uncontrolled dumping on land may pollute ground water resources and cause hazards when the land is reused in the future. Cleaning up pollution caused by past dumping of hazardous waste is much more expensive than correct management in the first place.

Developing countries can learn much from the experience and mistakes of industrialised countries in controlling hazardous wastes. Sophisticated control methods and technologies cannot simply be transferred, a certain amount of adaptation being necessary to local needs and circumstances. Moving from a situation of little or no control to one of absolute control is not possible; in most developed countries, the control system has evolved gradually over a period of perhaps twenty years.

Countries in Asia can develop a two part strategy for controlling hazardous wastes, implementing a short term action plan including interim treatment and/or disposal facilities, as a first step towards a long term plan. The considerable immediate reduction in risk that interim arrangements for hazardous waste treatment and disposal can give should not be underestimated. Equally, interim solutions should be recognised for what they are, that is a first step leading on to more permanent measures.

Examples of interim measures include the following:

***

Copyright © 1993, ECO Services International