2. Environmental impacts and protective measures
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2.1 Definitions according to the Basel Convention
The "Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal (Basel Convention)" of 22.3.1989 can be regarded as an important step forwards in the development of an international environmental law. This convention is the result of many years intensive consultation with the participation of over 100 states. It provides a basis for the necessary restraint of the increasingly problematic and to date virtually uncontrolled transboundary movements of hazardous wastes, some of which are declared as economic goods, which are sent to other countries for disposal. It is very helpful for the international harmonisation of the term "hazardous wastes".
The term "hazardous wastes" is more closely defined in Article 1 (see Annex 1 in conjunction with Annex III). In addition, however, the signatory countries to this convention also have the possibility of closer national definition, by subsuming further types of waste under the term "hazardous wastes" on the basis of national legislation.
Within this Basel Convention, of worldwide importance, Article 2 defines the "environmentally acceptable management of hazardous wastes and other wastes" as "taking all practicable steps to ensure that hazardous wastes or other wastes are managed in a manner which will protect human health and the environment against the adverse effects which may result from such wastes."
For a more detailed specification of the term disposal, the same Article refers to the operations listed in Annex IV to this convention. The above-mentioned Annexes with the types of waste, hazardous characteristics and disposal methods can be found in Annexes 1 - 3 of this document. Annex 4 gives a list of the hazardous materials, as taken from the Annex to the EC Directive on toxic and dangerous waste. This shows the extent to which the Basel Convention is based on this EC Directive.
2.2 Specific problems in developing countries
The situation in developing countries is typically characterised by the following problems in handling and treating or disposing of hazardous waste:
1. The hazardous nature of these substances for man and the environment, as well as the resultant need for action is not recognised, or is insufficiently recognised by the operators of industrial plants (waste generators), political decision-makers and the general public.
2. There is no political or economic-policy framework aimed at avoiding or reducing hazardous waste; at the same time, the legal framework for disposal monitoring, including the administration necessary to implement the standards, is inadequate.
3. A proper disposal facility and a suitable monitoring system for these substances is lacking.
4. Accompanying observations and monitoring of air, soil, water etc. are not carried out or are carried out only in a rudimentary manner.
Certain secondary conditions restrict the scope for action and decision-making. Some of these restrictions which are of particular relevance in developing countries are as follows:
· limited financial resources: particularly convertible foreign currencies
· shortage of human resources: particularly in the fields of engineering sciences, management and administration
· limits to land use: in particular because of the high population concentrations at certain points in urban areas (polarisation)
· local environmental conditions: in particular because of the relative shortage of water resources and the fact that in areas of high population density in developing countries the groundwater table is usually close to the surface, so pollution can have devastating consequences for health and the environment.
Environmentally acceptable special waste management must take these factors into account. Some of these side effects may be so serious that in view of the inadequate disposal facilities there is no alternative to waste minimisation.
2.3 Survey of the types of waste found in developing countries
As already stated, the quantity, type and composition of special waste primarily depend on the industrial operations within the geographical area in question. Furthermore, complex imported goods are relevant to the waste situation. The economic and sectorial structure typically found in developing countries is often characterised by a high level of standardised production processes in the secondary (industrial) sector, using processes which as a rule do not correspond to the state of the art in industrialised countries and tend to be much more waste-intensive (though this does not necessarily involve hazardous waste). Moreover the primary sector (agriculture, forestry and mining) plays an important part. Specific types of waste are produced by these sectors, particularly bulk waste with a varying hazard potential. For example, waste heaps, sludge lagoons, and liquid discharges may contain toxic heavy metals (Hg, Cd, As, Pb etc.), radioactive substances and cyanides. This applies particularly to non-ferrous and precious-metal mining.
Problems must always be expected in dealing with the following substances, which, unlike the more general wastes from industrial production, can also result from consumption processes:
· oils and oil-containing substances, some containing PCBs (e.g. from vehicle fleets, workshops etc.)
· agrochemicals and their residues
· hospital waste.
Building materials containing asbestos must also be considered.
2.3.2 Generation points
The most important sector for the generation of special waste is industry (taking into account imported industrial products). The generation points are hence the starting points for the reduction of waste production. They must be considered differently in the enterprises in question depending on the type of waste, hazard sources and possible recycling strategies:
- In point 2 reference has already been made to Annex I of the Basel Convention and the Listing of Waste Types provided therein, which fall under the definition of hazardous waste (cf. Annex 1).
- A further classification scheme for special waste with references to possible areas of occurrence is given in Summary 2 (Annex 6).
- Another waste classification differentiated by sectors for the occurrence of these substances is taken from World Bank Technical Paper 93 and set out in Annex 7.
- Reference should be made at this point to the schedule of special waste types in accordance with TA-Abfall [Technical Instructions on Waste Management] (or in accordance with the waste definition order AbfBestV) used as the basis in Germany, in which examples of areas of origin are given. TA-Abfall also gives disposal recommendations for the types listed therein and which are given a waste code.
In the past, the following industrial sectors have proved to be particularly large producers of "special" waste:
· chemical industry and oil processing
· pharmaceutical industry
· non-ferrous/ferrous metal industry
· vehicle manufacturing/mechanical engineering/surface treatment industry
· electrical engineering/precision engineering
· printing trades/dyes and pigments production and processing
· plastics processing
· glass processing
· leather manufacture
· asbestos processing
· mining, metallurgy, smelting
Consumption activities and the services sector generally produce much smaller quantities of waste. Oil-polluted waste often creates specific disposal problems in developing countries. The Table in Annex 8 gives an idea of the types of special waste produced in small establishments and by the use of certain products.
The area of complex imported goods poses a particular problem. Such substances often give rise to serious problems of disposal and handling after they have become waste. This must be taken into account beforehand, i.e. at the time of importation; possible solutions include import bans or obligations to take waste back.
Particular attention must be paid to special hospital waste, already mentioned above. This may give rise to very serious health problems (cf. environmental briefs Analysis, Diagnosis, Testing; Public Facilities).
2.3.3 Identification of waste
In Summary 1 (Annex 5) a simple form of classification and identification of waste materials has already been proposed. Chemical laboratory analyses offer important detailed identification methods, but these can involve a great deal of work and expense, and suitable laboratory installations are not always available. It is more practical to examine the production processes. Because of their standardisation, one generally knows what waste materials and related products are produced by the various production processes. Further investigation can then be carried out, comparing data sheets on the various material properties. Such data sheets are available in a number of countries; in Germany, for example, in the form of continuously updated loose-leaf collections. These describe substances by their chemical properties and appearance, which is a help in identifying substances.
In the USA there is an official register of hazardous materials (Federal Register), which is constantly revised and updated. Other countries also have detailed, statutory regulations and classifications for handling of materials and for reducing the hazardous effects associated with them. Annex B of TA-Abfall already mentioned above gives detailed sampling and analysis procedures for the declaration and identification of hazardous waste, with reference to the relevant German DIN standards.
The basic problem in identifying waste is that substances generally become mixed, so that conclusive identification is not possible on the basis of the material properties alone. Added to this, many substances are difficult to analyse, particularly those which can be toxic in very small quantities (e.g. dioxins, furans).
2.3.4 Ways of allocating hazardous waste to environmentally acceptable disposal methods
Whether such allocation will lead to environmentally acceptable disposal depends primarily on the type and equipment of these plants (i.e. the state of the art reached). Statutory provisions must ensure that priority is given to recycling waste wherever technically possible (i.e. where a suitable process is available) and economically feasible (i.e. any additional costs are offset by corresponding revenues).
When allocating waste to appropriate disposal routes, the following aspects are important:
· appearance, colour,
· combustibility under normal conditions,
· reactions with water, air and other substances,
· reaction products from the anticipated disposal route
In addition, there are many other criteria which should be examined on a case-to-case basis.
Whether waste can be dumped on a landfill site depends mainly on the elution behaviour. Particularly reactive substances may only be incorporated after appropriate pretreatment. In principle, inorganic, solid or compact wastes are suitable for tipping. Annex D of TA-Abfall lists a large number of criteria for overground tipping, which is the main disposal method in developing countries (cf. Table 1). This comparatively cheap disposal option should always continue to be used when "geological barriers" (impermeable rocks such as clays and marls) of sufficient thickness (several tens of metres) are identified and/or can be reinforced or replaced by technical barriers (artificial membranes).
Table 1 - Allocation criteria for overground tipping in accordance with German TA-Abfall
|Side shear strength||>||25||
|Unconfined compression strength (flow value)||>||10||
|Loss on ignition of dry residue of original substance||<||10||
|Extractable lithophilic substances||<||4||
|Cyanides, readily liberated||<||1||
Chapter 6 (Hazardous Waste Treatment Technologies) and 7 (Technical Requirements for the Safe Disposal of Hazardous Waste) of the joint study by the World Bank, WHO and UNEP "The Safe Disposal of Hazardous Waste, World Bank Technical Paper Number 93" in volumes II and III offer assistance for more detailed examinations.
Special wastes should only be disposed of by incineration where (assuming they have sufficient calorific value for incineration in e.g. rotary kilns as used in the cement industry) they are unsuitable for overground tipping because of their organic pollutant content and where, in addition, this heat treatment guarantees the safe destruction of these troublesome components. Wastes suitable for incineration contain only limited quantities of heavy metals and heteroatoms (fluorine, chlorine).
The different types of chemical/physical and biological special waste treatment serve to reduce the pollutant content and/or quantity of the waste. These are used for wastes with a high pollutant content and where the process enables separation, conversion or immobilisation of the environmentally polluting components.
Wastes are allocated to the most environment-friendly disposal method by means of a suitability test, which is generally carried out on the basis of waste composition analyses. When the waste composition is known, the waste may be allocated on the basis of disposal recommendations.
2.4 Identification of hazards due to incorrect handling of special waste
The study of the dangers of handling hazardous waste materials varies considerably depending on the specific material properties, subdivided into the phases of collection, transport and treatment/disposal. Various types of hazard must be distinguished in terms of their effects on man and the environment.
The anticipated environmental disturbances again largely depend on the material properties (e.g. bio-toxicity, human toxicity, degradability, accumulation properties, mobility). Obviously it will be impossible, within the framework of this study, to define these for the vast number of hazardous waste materials (cf. more detailed study in World Bank Technical Paper Number 93, Chapter 2 Volume I).
For the individual stages of waste disposal, on the other hand, a number of general observations may be made. Complete recovery (collection) of waste materials at the generation point in suitable receptacles is essential for environmentally acceptable disposal of this hazardous waste. The collection receptacles used for this must be appropriate to the material properties of the substances (e.g. flammable, explosive, corrosive etc.) and take into account other aspects (strength, resistance, density, logistical suitability etc.). In addition, they must be of adequate size to accommodate the regular volume of waste generated.
It should be noted that mistakes which are made at this stage of waste disposal are often unrectifiable later on. Conclusive identification of the waste to ensure appropriate collection is of paramount importance.
The same applies to transport and disposal and to the recycling or treatment of these hazardous materials. Some countries already have regulations containing detailed disposal recommendations for the relevant types of waste, e.g. in Germany, the TA-Abfall. Within the EC, Directive 80/68/EEC on the protection of groundwater against pollution caused by certain dangerous substances is applicable (subject to the implementation period since the end of 1981). The USA and other countries also have appropriate statutory regulations in this area.
2.5 "Source-Transport-Destination" hazard assessment
In view of the aspects described above a detailed hazard assessment can only be carried out in the light of specific hazard factors. However, a number of general comments can be made which will serve to illustrate the general principles.
2.5.1 Stages of hazard assessment
A hazard assessment consists of several stages. To start with there is the inventory analysis, whose function is to provide an accurate pollutant inventory listing. This is the total of all substances which may in principle pose a long-term threat to man and the environment. In the case of "special waste disposal" this will clearly depend to a very large extent on the composition of the waste and the method of disposal.
The second stage is the emission analysis, in which an attempt is made to determine the discharge of pollutants actually occurring. This is determined by the mobility of the pollutants.
In a third stage, an exposure analysis is carried out, the function of which is to consider the possible pollutant burden paths for goods and people. Such burden paths may be:
|contamination of the groundwater||®||drinking water|
|pollution of the air||®||inhaled air|
|discharge of pollutants into the soil||®||food chain/groundwater|
|uptake of pollutants through dermal resorption||®||skin contact|
As a final stage, the actual risk analysis is carried out. This assesses the effect on the environment and human health of the hazards and risks resulting from the different exposures. This is done on the basis of limit values, where available, or in the form of individual assessments. The hazard model also includes further aspects such as the weighting of risks of occurrence and an estimate of possible effects of damage or incidents.
The following discussions should help to recognise or to reduce the hazard factors associated with handling special waste.
2.5.2 Source: Waste generation points
As already mentioned, hazardous waste originates mainly from industrial production or imported goods; hazardous waste can also arise in the areas of agricultural production, mining, conversion of raw materials, consumer goods and capital goods. The following general rules may be applied for handling such materials, so as to minimise the associated hazards:
· mixing ban:
recovery and collection of substances in receptacles appropriate to the material properties and ban on mixing different types of special waste,
· regular checking of waste composition,
· observance of safety regulations during handling and temporary storage of hazardous waste,
· preparation of contingency plans for possible incidents,
· training to be provided for personnel involved in the handling of the materials.
The transport of hazardous waste differs very considerably in developing countries from the common practice in industrialised countries. On the one hand one can assume relatively low traffic density - a positive factor in a comparative hazard assessment. However, there may be very high traffic concentrations in some densely populated areas with at the same time a very poorly developed transport infrastructure in terms of traffic routes, with unsuitable modes of transport and often inadequate vehicle safety standards.
Problems therefore exist primarily because of the following factors:
· poor traffic routes,
· overstretching of existing transport facilities, especially in the vicinity of urban centres,
· inadequate vehicle safety,
· drivers inadequately trained to handle dangerous materials.
To draw conclusions in order to make a hazard assessment, it is necessary to determine:
The choice of transport mode and the route should be based on such considerations.
If one compares these countries with the practice in many other countries, where substantial resources are devoted to the administration and monitoring of waste transport, one will appreciate the importance attached to this area. Besides national regulations there are also international and supranational provisions in force in the transport sector which must be observed. The United Nations have also prepared regulations on the carriage of hazardous goods, differentiating the hazard classes by hazard characteristics of the goods to be transported (cf. also Annex 3).
2.5.4 Destination: Special waste treatment/disposal plants
The environmental hazards arising from treatment/disposal plants for special wastes depend primarily on the method of waste disposal or treatment and the suitability of the substances for these methods. The principles of location planning are dealt with in a separate environmental brief.
The large number of thermal, chemical/physical or biological treatment processes available mean that specific environmental restrictions have to be imposed. It is therefore important to subject only appropriate and permitted wastes to the relevant processes. Regulations should be drawn up in this regard, or existing ones adapted, to ensure the exclusion of unsuitable substances from certain disposal methods (e.g. Table 1 gives a list of requirements for overground tipping of wastes). Allocating certain wastes to defined disposal methods or, as a first step, excluding such materials from unsuitable disposal procedures can bring about a major improvement in special waste disposal leading to less environmental pollution (see also 2.3).
Chemical/physical and biological methods of special waste treatment represent only a very small part of developing countries disposal capacity.
Generally speaking, the main disposal methods of landfill and incineration involve various forms of environmental pollution and hazards. A special waste incineration plant may sometimes produce sporadic emissions, while in the case of landfill sites for special wastes, insufficient knowledge of the long-term behaviour of the structure poses fundamental problems. The medium of water (groundwater and surface water) is particularly at risk from the tipping of waste materials and must be considered carefully. Overground landfill sites often pose serious environmental hazards because of polluted leachate. Here too, it is advisable to assess the specific dangers posed by the individual substances present, therefore a careful analysis must be made to determine which substances must be allocated to which waste treatment or disposal procedures. Specific legislation should be passed in this regard using exclusion criteria or more extensive allocation provisions.
With regard to hazard assessments to determine the potential adverse effects on the local population, it can be said that thermal waste treatment plants are usually located near areas of high population density and therefore pose different hazards (health risks e.g. due to accidents or dioxin emissions from waste incineration and particularly special waste incineration) from landfill sites which, because of land-use priorities, are more remote and very land-intensive. It should also be taken into account that dumping is an unavoidable part of all treatment processes, as substances are always generated which cannot undergo any further treatment and therefore must eventually be dumped.
To minimise the hazards associated with the two main disposal methods, the following measures must be adopted or allowed for:
Special waste incineration:
· Operation/execution of thermal treatment:
Rotary kilns with an incineration temperature of 1000-1200° C are particularly suitable;
Efficient waste gas cleaning / flue gas scrubbing is vital.
Special waste landfill:
· Choice of suitable location taking into account geogenic conditions,
· Structural measures:
Base sealing (natural/synthetic), capping, control of density, minimisation of leachate, recovery and treatment of leachate, degassing measures.
· Landfill operation
Measures to avoid drift and noise emissions, minimisation of leachate, compaction, consolidation, noise protection, separate tipping/incorporation of certain waste materials, measures to guard the site, incident precautions,
· Monitoring after closure of the site:
Inspection shafts above and below the groundwater flow.
2.6 Elements and stages of environmentally acceptable management of hazardous waste
A schedule of waste types must be established indicating precisely defined waste characteristics. Summary 1 in Annex 5 is an excerpt from a simple and practical classification scheme, which already provides a good basis for assessment of substances and appropriate handling of the waste thus classified.
2.6.1 Stages of waste management planning
The subsequent, second stage involves planning of specific handling measures for the further handling (collection-transport-disposal/treatment) of the materials and evaluation of the resultant hazards given the specific local context of these stages
· collection/separate collection - with temporary storage where applicable
· transport - with loading and unloading where applicable
· disposal - according to treatment/disposal method.
The planning result will depend on the specific material properties, which are known in most cases. One must however bear in mind that the waste materials are mixtures, which makes it difficult to evaluate and classify them, and again requires knowledge of the waste composition. Furthermore the local socio-economic and geo-ecological conditions must be taken into account, where these have obvious effects.
Such aspects include - lifestyle and consumption habits,
- forms of settlement and land-use
- economic structure,
- population density and distribution,
- soil composition,
- existence and availability of water resources,
- climatic situation, etc.
These and other factors therefore affect the planning result and the assessment of the resultant hazards. Thus it is imperative that the assessment, leading to an environmentally acceptable disposal practice for hazardous wastes, be carried out taking into account the specific problems arising, using different criteria or a different weighting from those applicable in industrialised countries (ICs)
Furthermore, measures must be distinguished in terms of their efficacy over time and the period of time for which they are designed. On a short-term horizon, measures are necessary to do away with the most unfavourable methods of handling and disposing of hazardous wastes, while on a long-term horizon acceptable solutions must be found to develop a strategy appropriate to the scant financial and environmental resources available.
The starting point for identifying and controlling hazardous waste is an analysis of possible sources (i.e. waste producers/imports). Hazardous waste results from production processes and is a consequence of the consumption of goods. However, industrial production is a very important factor, so that the compilation (and later updating where necessary) of an inventory of industrial establishments in the planning area will provide valuable pointers to the special waste types anticipated and arising. This process of identifying the existing situation is therefore an important basic step in special waste management. Particularly in developing countries, one must consider complex imported goods, which may produce very troublesome hazardous materials at the end of their life cycle.
Proceeding on this basis, further information must be obtained for efficient waste management planning. The following important process stages should be mentioned:
1. Inventory of the present generation points: type, quantity and composition of hazardous wastes,
2. Estimate of future development,
3. Consideration of the occurrence of hazardous waste associated with imports,
4. Examination of the potential for safe collection and transport,
5. Inventory of existing and actually planned disposal/treatment plants for special wastes, by type (suitability for certain types of waste) and capacity,
6. Examination of possible alternatives identified in 5,
7. Examination of potential for waste minimisation through avoidance (e.g. use of new, environment-friendly technologies) and opportunities for marketing any recycled products (thermal/material),
8. Allocation of certain waste materials to suitable disposal methods (compilation of an allocation schedule or formulation of exclusions),
9. Preparation of longer-term, regionally coordinated waste management plans.
In addition to or alongside the above, further activities are required:
- creation of a legal framework for waste management planning (legal foundation),
- legal establishment of priority of avoiding or recycling waste materials over (environmentally acceptable) disposal,
- prohibition of importation of hazardous waste within the meaning of the Basel Convention,
- verifying the appropriateness of an import ban on imported goods producing hazardous wastes at the end of their life cycle,
- establishment of the need for an environmental acceptability test in the case of important special waste disposal measures,
- legal establishment of defined planning stages in the construction of new plants for the disposal of hazardous waste (establishment of approval procedures),
- development of an administrative apparatus with clearly defined powers and responsibilities for implementing the regulations governing environment-friendly waste management,
- development of an effective system of sanctions
- establishment of rules governing liability for damage to property, ecological damage and human injury as a result of violations of the principles of environmentally acceptable waste management.
- development and implementation of a system of economic incentives to avoid and minimise the occurrence of hazardous waste (e.g. by levying charges),
- establishment and implementation of the polluter pays principle as a guideline for waste management,
- creation of local markets for used and residual materials,
- provision of waste banks for certain materials.
- measures to ensure that people working in this area have the relevant qualifications,
- training for a wider circle of people (e.g. plant operators, drivers, administrative staff),
- establishment of regionally coordinated waste management plans/planning aspects
2.6.2 importance of measures to avoid/minimise waste and promote recycling/reuse.
Stages 1 - 5 are the main steps towards waste management planning; stages 6 and 7 aim for minimisation of waste quantities, which will form the centrepiece of future waste management systems. Preventing hazardous waste from occurring in the first place (e.g. by using safer substitute materials or changing to a different system) is now and will in future be a basic and indispensable part of special waste management, of particular importance in developing countries.
Various measures can be taken to avoid and minimise special waste produced by commercial and industrial establishments:
· input of low-polluting raw materials (with pretreatment where applicable);
· use of production processes generating minimal waste and residues;
· minimisation of pollutant burdens in the residual materials produced;
· use of closed circuits for recycling of residual materials;
· separation of domestic type waste and special types of waste.
A further important step is the enshrinement in law of an obligation to recycle waste before disposal of hazardous wastes. This should be accompanied by measures to develop local markets for used and residual materials.
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