Improper disposal of hazardous waste is an increasing problem in many developing countries. Typically (but not ideally), the first stages of pollution control focus on the discharges to air and water, leaving a wide range of other materials which are poorly controlled. These materials include substances which pose serious threats to public health and the environment and which are considered hazardous under almost any definition. Examples would be sludges from chemical plants, clinical wastes, contaminated oils, and metal-bearing wastes.
Materials of particular concern are those which do not degrade quickly in the environment (such as metals and persistent chemicals) and which can therefore pose a threat for long periods into the future.
Proper management and disposal of hazardous waste is expensive and therefore illegal dumping is common in many areas. The consequences include not only environmental degradation but also the undermining of legitimate waste management systems. Control of dumping is therefore a key issue to be considered when designing and implementing regulations.
The Bank can assist governments in designing and implementing hazardous waste management systems and in the provision of appropriate treatment and disposal facilities -- often with the involvement of the private sector.
Scale of the Problem
Hazardous waste can be defined in a number of ways including:
hazardous characteristics (e.g. toxicity, flammability);
certain toxic components (e.g. PCBs, arsenic);
types of materials (e.g. organic solvents, explosives);
processes from which they originate (such as refinery residues or clinical wastes);
specific waste streams (such as chemical wastewater treatment sludges).
Defining hazardous waste is a difficult issue but for developing countries the establishment of a proper management framework should not be delayed by debates concerning what constitutes a hazardous waste. Pragmatic working definitions can be adopted initially and refined as the system is developed.
Many countries adopt an inclusive approach, which specifies those wastes which are to be considered hazardous, for the purposes of regulation. Clearly there have to be procedures for granting exceptions and for adding and deleting wastes.
An estimate of the total volume of waste produced is necessary for planning purposes but such estimates are very unreliable and too much effort should not be put into trying to refine numbers. The uncertainties arise in several ways. To begin with, recorded data on waste quantities is almost never available and therefore quantities have to be estimated on some basis such as numbers of firms, value of output or number of employees. The coefficients for such estimates are very unreliable and the resulting figures can vary by an order of magnitude. Even where estimated quantities are available, definitional questions can have a major impact. For example, mining or materials processing wastes can often be a major portion of the total and re-classification of these can have a significant effect on the estimates of total 'hazardous' wastes.
A related planning problem is the highly elastic nature of waste generation. Once real disposal costs are imposed on the generators (through regulatory effort) the reductions in waste quantities can be dramatic. Experience has shown that wastes delivered to treatment facilities has in some cases been only one-third of the design estimates of wastes generated. This drop is ascribed to a combination of waste reduction and evasion of the regulatory system.
For practical purposes therefore, estimates of quantities should be based on a relatively narrow definition (perhaps in terms of specific industries and/or process streams) and realistic allowance should be made for the effects of waste minimization.
Policy and Regulation
Hazardous wastes are by their nature a threat to public health and the environment and therefore need to be regulated under the full force of the law. However, management of hazardous waste is a complex issue and regulations must be developed within the context of a comprehensive policy, covering the responsibilities of different parties, methods for defining hazardous waste, incentives to reduce quantities, education of waste generators and the public, the establishment of approved facilities (with particular concern for criteria for siting) and systems for control and monitoring of the movement and disposal of hazardous waste.
Legislation on hazardous waste should be coordinated with other related topics such as management of hazardous materials and industrial health and safety.
The establishment of a hazardous waste management system is often complicated by a 'chicken and egg' problem: legislation will require disposal in approved facilities but such facilities are expensive and will usually not be established until after legislation and enforcement have demonstrated the scale of the 'market' for proper disposal. In the initial stages therefore, industry may be in the position of having no realistic options for compliance with the law. The government’s policy must therefore address the problems of phasing-in the new regulations, by assisting in the provision of some acceptable facilities or by licensing interim solutions.
There have been a number of cases of export of hazardous waste from countries with strict regulations to those without similar controls, resulting in serious pollution problems in the receiving countries. This trade in hazardous waste is now controlled under the Basel Convention (the Global Convention on the Control of Transboundary Movement of Hazardous Wastes, adopted at Basel in 1989).
The Convention also promotes the development of sound national management of hazardous wastes as a prerequisite for the control of transboundary movement.
Components of a Management System
Ideally the generation of hazardous waste should be avoided altogether. It is clear from experience in industrialized countries which have strong hazardous waste controls that it is possible to achieve the elimination of certain wastes and major reductions in others. This is achieved through imposing the real costs of disposal on the generators, at which point the incentives for cleaner production and waste minimization become very strong.
Where the production of the hazardous waste cannot be eliminated then action should be taken to reduce the hazardous characteristics by treatment or immobilization.
Responsibility for Wastes
Unfortunately, proper treatment and disposal is costly, while illegal dumping is very cheap and therefore profitable for illegal waste haulers. An effective control system is therefore essential both to protect the environment from the illegal dumping and to internalize the disposal costs to waste generators, in an equitable way.
The basic principle underlying control systems is that waste generators should be responsible for the final disposal of their wastes, in an acceptable manner.
In practical terms, there are three different actors to be considered in the management of the waste: the generator, the disposal facility and the transporter of the waste between the first two. The law will normally put the responsibility on the generator but there must be a system which allows the government to monitor the movement of waste from the generator to approved disposal.
Such a system normally consists of a number of elements, including formally placing responsibility on the generator to prove that he has complied with disposal requirements; licensing of waste haulers and disposal facilities; and establishment of a manifest system to track the movement of waste.
The design of a manifest system requires care, to provide sufficient control without generating excessive administrative or regulatory effort. The basic principle is that each load of waste is accompanied by a multi-copy document which identifies the characteristics of the waste, the approved disposal facility and the responsible companies or individuals. Copies of the manifest are held, at a minimum, by the generator and the disposal facility and can provide valuable information to the authorities about patterns and trends in waste generation and disposal as well as allowing for compliance with regulations to be confirmed.
Storage of Hazardous Waste
A hazardous waste management system should include regulations governing the storage of hazardous waste at the generator’s site or at any other transfer or disposal facility. In the absence of approved (or affordable) disposal options, it is common for generators (or transporters) to store wastes as a stop-gap measure but this approach can result in neglected piles of deteriorating wastes, posing significant hazards. It is therefore not acceptable to allow generators to stockpile wastes over an extended period of time as a way of avoiding the problems of disposal.
Treatment and Disposal Facilities
Hazardous waste facilities frequently comprise storage, recovery and treatment stages as well as final disposal. This allows the facility to take advantage of economies of scale, of opportunities to blend different waste streams and to recover some materials (particularly oils and solvents). Such a facility can be complex and needs proper management and supervision. Potential operators need to demonstrate the necessary technical, financial and managerial capabilities before a license to operate is issued. Any discharges from the site to air or water need to be very closely controlled and monitored.
Final disposal is almost always incineration or landfill. (Since incineration generates an ash, which is normally landfilled, it is sometimes considered as a treatment step rather than final disposal but this distinction is not often important).
Incineration involves the thermal destruction of gaseous, liquid or solid wastes. Thermal oxidation converts complex organics into simple compounds, greatly reduces waste volumes and can recover the heat content of wastes. Incineration requires relatively high temperatures (typically above 1000oC), normally requires control of flue gases and generates small quantities of ash or slag.
Hazardous waste incineration normally takes place in purpose-built facilities whose high capital and operating costs require significant throughputs for economic viability (typically upwards of 10,000 tonnes per annum). This required scale limits their feasibility in many newly industrializing countries.
Successful incineration requires good design and careful operation. The key operational characteristics are the temperature, the residence time and turbulence in the combustion chamber, all of which affect the efficiency of the destruction. A poor installation can emit particulates, acidic gases, unburned waste and trace quantities of hazardous organic by-products. Some wastes, such as PCBs, require very careful control, to ensure minimum temperatures are maintained, for example.
The incineration of selected wastes is possible in high temperature process plants such as cement kilns. However, the waste stream must be controlled to those wastes for which full destruction can be assured and no unacceptable residues are emitted.
Incineration is an accepted form of disposal for certain wastes in industrial countries, where careful gas cleaning and monitoring are required. Similar systems can be suitable for developing countries if adequate attention is given to the management and monitoring aspects.
The final disposal for many hazardous wastes or their treated residues is controlled land disposal. However, a properly located, engineered and operated hazardous waste landfill is a major facility and is not to be confused with the uncontrolled or open dumping that frequently occurs. Such controlled or 'secure' landfilling should be used only for the minimal quantities of remaining wastes after all possible reduction and treatment has been carried out.
The main environmental threat of a landfill is water pollution and therefore a landfill should be sited where the geological and hydrological characteristics are least likely to allow impacts on groundwater or surface water.
A well designed secure landfill will normally be divided into a number of cells to allow for better control of operations and to allow segregation of incompatible wastes. The landfill will be lined (often with a double or even triple lining) and will have leachate collection facilities and groundwater monitoring systems. The design will include for the closure and long-term monitoring of the site.
Operation of the landfill will include requirements for pretreatment and containment of wastes, control and recording of the burial of different waste types, planning and preparation for spills and accidents and regular monitoring of the surrounding environment.
The joint disposal of domestic and certain selected industrial wastes in a properly designed and operated municipal landfill may be acceptable as an interim measure or where investigations have demonstrated that the wastes involved are compatible (for example waste motor oils or some sludges may be acceptable). However, such joint disposal should be carefully controlled with regard to the type and quantities of industrial wastes and should not be used as a cheap alternative to proper management of these wastes.
Development of a Hazardous Waste Management Plan
A systematic approach to developing a national hazardous waste management plan is set out in Batstone et al (1989). The key steps listed can be summarized as follows (the reference gives further details):
define the scope;
define the objectives and constraints;
formulate the key questions to be addressed;
collect the necessary information;
prepare a technical assessment of appropriate available technologies;
review the existing situation and develop a short-list of critical problems and the technical options;
prepare a number of alternative management plans, based on the preferred technical options;
review, discussion and feedback;
decisions, implementation and regular monitoring and adjustment.
Economic Justification of Hazardous Waste Management Programs
Given the amount of public attention focused on hazardous waste, it is surprising how little is known about the nature and the scope of the risks involved.. While the potential risks to public health from exposure may be significant, little is known about the actual risks to public health. There is a significant lack of epidemiological dose-response data linking the level of exposure to various toxins in the ambient environment to human health impacts. The lack of solid data on risks will continue to limit our understanding of the benefits of hazardous waste regulation. Very few studies or formal risk assessments have been conducted in the vicinity of abandoned or currently operating facilities. In addition, examples of where there have been significant and direct health impacts from hazardous waste are limited (Minimata, Itai-itai, pesticide poisonings). While the risks to human health are difficult to calculate, damages that can be more clearly associated with hazardous waste are the loss of value in contaminated land and the loss of productive water supply aquifers.
Uncertainty about risks causes uncertainty about regulatory benefits. The current limited knowledge of the chronic health effects of low exposure to many hazardous wastes makes it virtually impossible to estimate the benefits of reducing the impacts. One economic justification of a hazardous waste management program is the benefits in terms of future clean-up costs avoided. However, given the uncertainty about the location and extent of future damage and rules for the level of clean-up that might be required, the estimation of benefits is extremely uncertain. In fact, numbers from the US experience show that benefits in these cases are more often low rather than high. It is difficult to compare hazardous waste to other environmental problems where it is easier to estimate benefits in terms of overall reduction of risk to public health.
An economic-based approach to managing hazardous waste take advantage of incentives to reduce risks while balancing the costs and benefits of doing so. One way of achieving this is to tailor requirements to reflect the wide variations that exist in the risks of different waste types, disposal sites, and exposure conditions (rather than regulating facilities at the same level), and concentrating resources on the worst risks first.
Siting - a Critical Issue
The location of a hazardous waste facility requires careful consideration of a wide range of technical, economic and social factors. It is often a controversial process because of local opposition and many schemes have been delayed or abandoned because of difficulties in obtaining an acceptable site. There is a clear role for the government in leading the siting process and ensuring that clear information is provided, that there is a process by which local concerns are taken into account and that realistic commitments are made about control and monitoring of operations. An environmental assessment will normally be required, depending on the type, scale and location of the facility being proposed.
Financing and Funding
Proper management, treatment and disposal of hazardous is costly and there are strong incentives for generators and transporters to avoid paying the real costs. In practice, it has normally been very difficult to implement a realistic system of charges for hazardous waste without a strong enforcement regime, which is itself rare. The consequence is that it is almost impossible, especially in the early stages of a new system, to generate an adequate revenue stream to cover the costs of the necessary facilities. In the absence of a reliable revenue stream, it is then difficult to finance the capital investment required. (The lack of an effective system to impose costs on generators also undermines any financial incentive to adopt waste reduction measures.) International experience indicates that integrated hazardous waste treatment facilities are typically not commercially viable outside of well regulated industrialized countries.
Without a credible government-driven market for hazardous waste management infrastructure, it is difficult to expect investment by industry or the financial sector in this area. In this case, a transition period of blended incentives (carrots) and disincentives (sticks) can be used, as was the case with many OECD countries and has been used more recently in Asia. Subsidized seed capital and targeted credit, for a limited period of time, can be used to help ease the adjustment of industry into a tighter regulatory environment as they face one-time adjustment costs, as well as to strengthen the environmental services industry’s ability to provide hazardous-waste management related services.
Role of the Private Sector
The overall design and implementation of a hazardous waste management program is normally a government function but the private sector can play a major role in the provision and operation of the necessary facilities.
Transport of waste is nearly always a private sector function although careful control and licensing by the relevant authorities may be required.
The design, construction and operation of treatment and disposal facilities are frequently carried out by the private sector. However, particularly in the early stages of a hazardous waste management program, government involvement may be required in the siting and initial development of key facilities. In most cases, some practical demonstration of government commitment to regulation of waste generators and haulers may be required to convince the private sector to invest in major facilities.
A national or regional hazardous waste management plan should identify existing hazardous waste dumps, illegal sites or areas contaminated by toxic or hazardous materials. However, the costs of remediation can be very high and careful assessments of the benefits should be carried out before any commitments are made to spend public funds on clean-up.
Experience in the USA and the Netherlands with high clean-up standards has shown that the result can be very costly projects without corresponding levels of benefits. An alternative approach is to design clean-up to meet the requirements for realistic subsequent land uses.
Scale and Costs of Facilities
Some indicative values can be given for the scale and cost of typical facilities.
The construction costs for a secure hazardous waste landfill will obviously depend on the size and but a facility capable of accepting 100,000t/y would probably cost $3-8m for initial construction. The planning, siting and permitting processes can add 10-20% to this cost.
The economic minimum size for an integrated facility (treatment, incineration and landfill) is probably of the order of 20-40,000t/y capacity. Such a facility would cost $20-50m to construct (say $1000-1500 per ton capacity) and would require revenues of perhaps $500-1,000/t for profitable operation. In practice, such facilities are not usually commercially successful outside well regulated industrialized countries. For example, the Hong Kong government has developed a successful large, high technology facility but it operates at a low level of cost recovery.
More successful approaches are based on simpler facilities to deal with a somewhat limited range of wastes. One site with a stabilization system and secure landfill, together with the facilities for burning waste oil in a cement plant, is reported to have cost $20m for a total capacity of 70,000t/y (about $350 per ton capacity).
A 'Road Map'
Development of a hazardous waste management system is a complex and time-consuming task but experience suggests a number of pointers:
- there must be the political will to impose the costs on the generators, through enforcement or other persuasive mechanisms;
- start by dealing with the simpler problems for which there are well established technical solutions;
- address the siting problem early -- it is very difficult for the private sector to obtain sites without government involvement in the selection process. Where possible, use existing sites, as long as they are technically and environmentally acceptable;
- be skeptical about projections of quantities and design a flexible system. Support waste reduction and recycling efforts;
- focus on prevention of dumping: remediation of contaminated sites is usually a second priority.