Paper 04 1983 An Assessment Of Waste Disposal Options For The 1980s


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Paper 04 1983 An Assessment Of Waste Disposal Options For The 1980s

  1. 1. The Journal of the Royal Society for the Promotion of Health An assessment of waste disposal options for the 1980s A.E. Higginson The Journal of the Royal Society for the Promotion of Health 1983; 103; 16 DOI: 10.1177/146642408310300106 The online version of this article can be found at: Published by: On behalf of: Royal Society for the Promotion of Health Additional services and information for The Journal of the Royal Society for the Promotion of Health can be found at: Email Alerts: Subscriptions: Reprints: Permissions: Downloaded from by IGNACIO GARCIA MARTINEZ on November 29, 2007 © 1983 Royal Society for the Promotion of Health. All rights reserved. Not for commercial use or unauthorized distribution.
  2. 2. 16 An assessment of waste disposal options for the 1980s A. E. HIGGINSON, M.B.E., F.Inst.S.W.M., F.C.I.T., M.I.Env.Sc. Solid Wastes Management and Environmental Services Consultant — 1. PREAMBLE fanned by banner headlines stressing acute dangers of hazardous wastes, yet 90% of toxic wastes transported 1.1 There is always a starting point in any research or around the country are no more dangerous than petrol investigative work attributed to waste materials which conveyance and delivery. concentrates on technical feasibility of waste derived 2.3 Any alleged detriment to the environment must be fuel, mechanical sorting processes, the market accepta- identified and this is better demonstrated if the pollut- bility of the recycled materials, more cost effective ants have already been established and proper controls methods or methane production be it from domestic, mechanisms installed to cut off emissions, noise, dust, industrial or commercial wastes. odours or safety hazards. 1.2 Any consideration for future waste disposal 2.4 An analysis of waste disposal services indicate that options ranging over the next decade must evaluate they divide into separate aspects, each in themselves of these research studies that may suggest a new approach a complex nature because of the heterogeneous com- to perhaps a well tried and proven method such as position of the solid, semi-solid and liquid components landfill operations and the novel extraction of methane that make up the total involvement. for commercial purposes. 2.5 To identify the impact of wastes upon the envi- 1.3 Looking back over recent years has seen research ronment requires a check list of possible and known by industrial companies, plant and equipment manufac- sources of pollution during transportation to a central turers, universities and a broad band of subjects spon- facility site, increased traffic flow to the place of deposit sored or supported by the D.O.E. such as the £2m. causing possible nuisance from noise, fumes, visual Co-operative Programme Research on the ’Behaviour intrusion or accident risks. Poor storage arrangements of Wastes in Landfill’.~ There has also been a com- at transfer stations, incinerators or treatment plants can mendable fund of knowledge gleaned by some 23 Waste Management Papers on the management of attract flies and vermin. In landfill, leachate generation wastes published by the D.O.E. These have prescribed from decomposing wastes containing high concentra- guidelines for surveys, formulating a plan, Codes of tions of organic matter can cause environmental dam- Practice, treatment of difficult wastes, resource recov- age, these are some effects that may develop in provid- ery, with helpful statistics on arisings from different ing services. 2.6 The whole philosophy of landfill as a waste dis- sources. 1.4 With this background of latest knowledge waste posal option depends upon chemical, physical and disposal options can be assessed in the light of tech- biological changes to reduce wastes to gas, water, nological developments, environmental impacts of humus and inert materials but every stage of the to and process must be controlled to prevent pollution waste as resource an source recovery. energy water, air or soil. 2. ENVIRONMENTAL IMPACT ANALYSIS 3. THE LEGAL FRAMEWORK AFFECTING 2.1 It is fundamental that before any waste disposal DISPOSAL OPTIONS option is considered its environmental impact is asses- sed affecting local residents to where the facility is 3.1 The Control of Pollution Act 1974 is the major being contemplated or the general public if aerial legal framework although still not yet fully nuisance is a likely pollutant with fall-out over a larger implemented. It provides for a licensing system, power area. The provision of waste management services has to collect industrial waste, specifies criminal offences direct links with environmental matters and public and penalties, details arrangements for especially toxic, concern is of greater importance than planning the hazardous and difficult wastes and emphasises conver- necessary facilities for treatment and disposal of wastes sion of waste for recycling and reclamation purposes. if the proposed schemes are not be put in jeopardy. Some discretionary powers are left under the Public 2.2 The House of Lords Select Committee Report on Health Act 1936 relating to collection and disposal of Hazardous Waste Disposa 12 make this factor quite clear domestic and trade refuse but the main thrust of in their conclusion &dquo;Public hostility to hazardous waste legislative powers are in the C.O.P Act 1974. ,disposal facilities is common and is too important to be 3.2 Of recent years the impact of Health and Safety at ignored&dquo;. It can be further exacerbated if the disposal Work Act 1974 requires careful interpretation as dis- facilities are not for local wastes but for ’somebody posal of waste must be carried out without risk to else’s rubbish’. Professional officers may sometimes be employees or to the public. unaware of emotions expressed by some people for fear 3.3 With leachate generation from wastes in landfill of the unknown. Public hostility is often exaggerated sites being more strictly monitored the provisions of the Downloaded from by IGNACIO GARCIA MARTINEZ on November 29, 2007 © 1983 Royal Society for the Promotion of Health. All rights reserved. Not for commercial use or unauthorized distribution.
  3. 3. 17 Water Act 1973 must be closely observed to prevent TABLE 1 Quantities of Controlled Waste pollution of ground and surface waters. 3.4 The Refuse Disposal (Amenity) Act 1978 places a duty upon W.D.A.s to provide a facility at which refuse, other than trade or business waste may be deposited free of charge by the general public. In view of the enormous increase in this type of waste (20% by weight of all domestic waste in the G.L.C. area) the TABLE 2 importance of this feature in planning waste disposal is of Treatment and Disposal Methods fundamental. 4. RESTRAINTS IN PLANNING WASTE DISPOSAL 4.1 No disposal system can be developed unless it satisfies the requirements of legislation under the Town and Country Planning Act 1971 and the site licensing conditions that apply under Sect 5 C.O.P. Act 1974. It Total of Methods 1 Disposal 28,986 27,551 is pertinent to note that &dquo;conditions attached to plan- ning permissions should only have regard to matters TABLE 3 relating to the use and appearance of land in the Methods of Treatment and Disposal Costs per Tonne -Comparative planning context for waste treatment and disposal r&dquo;’-_6. A -- --- purposes, e.g. considerations of visual amenity, access, tree planting and preservation and landscaping gener- ally ; the site licence on the other hand will relate to the ) proper conduct of operations and day-to-day manage- ment of the site and plant, together with the protection of water, the environment and public health generally&dquo;. Quoting D.O.E. Circular 55/76 Para 43. 4.2 The site licence conditions apply only for the Accountancy Annual Statistics Source : The Chartered Institute of Public Finance and - Controlled Wastes England and Wales. duration of the licence. &dquo;It will not therefore be poss- ible for licence conditions to provide for continued There is a discrepancy in the totals showing quan- access and maintenance of bore-holes, leachate treat- tities and methods of disposal, this is due to double ment systems, etc., nor for the restitution of the site counting as waste is exported from one W.D.A. to after the licence has been cancelled or revoked. Condi- another and may appear under both but the overall tions attached to planning permission may therefore be effect is slight. Also within the average costs shown for appropriate when it is desirable to ensure that controls each method there are wide variations due to compar- apply after the expiry of a licence&dquo;. Quoting D.O.E. ing metropolitan counties, G.L.C. and the Welsh dis- Circular 55/76 Para 44. tricts all who have special local circumstances affecting 4.3 There are a number of consultations required choice of methods and the manner in which the services under the T. & C.P. General Development Order 1977 are carried out. before planning permission is granted, these refer to 5.3 Under Sect 2 C.O.P. Act 1974 a duty was placed such bodies as neighbouring district planning, neigh- upon W.D.A.s to prepare a Waste Disposal Plan and bouring county planning, water and highway although it was implemented lst July 1978 a comple- authorities. Similar consultations are required by the tion date was not mentioned. However most authorities W.D.A. under the C.O.P. Act 1974 that prior to the have been carrying out a survey on the sources and issuing of a licence to refer the proposals to the water arisings from household, commercial and industrial authority, the appropriate collection bodies for and authority wastes, what quantities are brought into their areas and ) under the Sect 6 prescribes the following exported. This was fundamental in discharging their purpose of Sect 5 and 11, the Health and Safety responsibilities to see what arrangements were neces- Executive and in cases of applications relating to pro- sary for the controlled waste arising from both the posals to deposit controlled waste in certain geological public and private sectors to ensure that the means of formations the Institute of Geological Sciences. disposal were adequate. Valuable advice on how to 4.4 It is with the foregoing restraints firmly in mind conduct a survey and prepare the Plan were given by that waste disposal options can be planned. The need the D.O.E.’s Waste Management Paper No. 2. Not only for strategically placed sites is overwhelming but disap- were waste arisings considered but the provision of pointment will be constant in trying to secure what disposal facilities with a forward look to estimate trends appears as the most desirous, economic, accessible site for the following ten years. and be subject to long and often acrimonious discus- 5.4 From the foregoing statistical evidence landfill of sions that ultimately abort the proposals. Yet waste is untreated wastes is the predominant method and offers continually produced and outlets must be assured lead- the lowest cost. But when considering future landfill a ing to extensive planning enquiries. number of constraints of recent origin i.e. Site Licens- ing and a Code of Practice imposes additional expendi- 5. QUANTITIES AND COSTS ture that causes other methods to be re-assessed for economic reasons and future strategies. 5.1 Before examining all the options available a gen- eral study of quantities of waste produced and the 6. PRACTICAL AND FINANCIAL existing methods of disposal with appropriate costs is a , CONSIDERATIONS good starting point for evaluation. 5.2 To help give a balanced view national statistics are 6.1 Although Sect 1 C.O.P. Act 1974 is not yet a useful guide :- implemented there is growing pressure among W.D.A.s Downloaded from by IGNACIO GARCIA MARTINEZ on November 29, 2007 © 1983 Royal Society for the Promotion of Health. All rights reserved. Not for commercial use or unauthorized distribution.
  4. 4. 18 for the Government to bring it into force without delay. relatively low cost against other methods. It also has The pressure has been re-inforced by the House of another advantage in that whatever other option is Lords Select Committee on Hazardous Waste Disposal selected a substantial tonneage of residues must be who in the Summary of Conclusions and Recommenda- landfilled. When properly carried out if fulfills three tions in Para 185.31 (2) stated &dquo;Positive planning of important functions, it is environmentally acceptable, it hazardous waste disposal facilities by W.D.A.s is reclaims useless or derelict land, it can create new land needed. Therefore Sect 1 C.O.P. Act 1974 should be forms by architectural landscaping and add to the brought into force and the plans under Sect 2 of that amenity and visual attractiveness of the area. Act should be expedited&dquo;. In reaching that conclusion 8.2 Why then is planning consent often resisted for the Noble Lords had considered a considerable volume what appears to be a suitable site. The answer is poor of evidence from wide ranging interests indicating that operational control in the past causing untidy condi- any future planning of disposal facilities for all kinds of tions and public resistance. controlled wastes depended upon the legislative back- 8.3 Fortunately site licensing and a Code of Practice up for the completeness of the C.O.P. Act so that for landfill now exists and the whole concept of site adequate arrangements are made for the disposal of all restoration by the use of waste as the principal infill controlled waste especially as it might need some form material is recognised by planning authorities providing of regional planning. The difficulties of implementation it is carried out to the highest standards involving were emphasised but the Selection Committee recom- capital works and strict operational control. mended to W.D.A.s to give special attention in plan- 8.4 There appears to be a misconception in many (a) public opinion, (b) growing ning disposal waste to quarters that void space for landfill is running out but scientific knowledge and (c) specialist facilities. national production figures from the minerals extrac- 6.2 The growing scientific knowledge referred to the tive industry indicate not only a present substantial research projects carried out and still in train giving a surplus but the extraction rate exceeds the infilling rate. wider understanding of the physical, chemical and These calculations emphasise sufficient void space is biochemical reactions taking place in mass waste dis- available for the next thirty years. posal. This knowledge is of more recent origin, for 8.5 It may be that a recommendation of the House of which great credit is due to the D.O.E. as it enables Lords Select Committee that &dquo;waste disposal W.D.A.s to plan with more certainty with guidelines to authorities should be formally grouped in Waste Dis- support intended strategies. There are still areas to be posal Regions to co-ordinate waste disposal plans and further investigated such as leaching in various geologi- the provision of facilities and to provide scientific cal strata, breakdown of organic compounds, incinera- services&dquo; has much to commend its adoption as waste tion of certain wastes and combustion conditions, long arisings and disposal sites often do not correspond. term stability of encapsulated wastes, health and safety Some of the metropolitan counties are desperately hazards. Where areas of doubt exist the use of specialist short of potential landfill space while their shire neigh- facilities at greater cost must be accepted to protect the bours do not have the problems of substantial waste public rather than a low cost but unsuitable disposal arisings from densely populated and high industrialised option. In turn the public must support any higher costs areas. There is also the site geology and hydrogeology incurred to prevent nuisance or environmental degra- that may restrict sites to emphasise that waste disposal dation in providing the ’best practicable means’. is better planned on a regional basis so that the criteria 6.3 The criteria that must be applied to all disposal on the merits and disadvantages of sites is properly options is public acceptability, that it meets environ- applied for permanent safety of groundwater quality. mental standards, is reliable and is economically jus- 8.6 To persuade the public that landfilling of untreated tified. This may rule out desirable methods involving wastes is environmentally acceptable will demand the intensive materials re-use or recovery. Many decisions highest standards of performance which requires the will emerge when the full financial implications of services of a wide band of skilled professional capital and future operating costs are assessed with engineers, civil and mechanical engineers, geologists, anticipated incomes. water and chemical and plant engineers all working together to use the best practicable means to restore 7. WASTE DISPOSAL OPTIONS derelict sites into permanently safe, attractive land- forms by the use of waste as a resource material. 7.1 Although many variations exist due to composite 8.7Extensive research into leachate generation and plants being introduced the choice of methods for disposal fall into five distinct categories: (a) Landfill of gas evolution has also pinpointed the awareness that untreated wastes; (b) Landfill with shredded or baled must be shown into these two problems of landfill when site planning takes place. The programme of research waste; (c) Incineration either direct, with heat recovery into the behaviour of wastes in landfill tried to set down or with some reclamation of constituents or with a guidelines for the selection of sites based upon the combination of all three systems; (d) Composting; (e) classification of wastes and their pollution risks but Resource Recovery Plant. 7.2 Although five methods of treatment have been found that classification of the type of site is safer than outlined there is no single system that might apply to all categorising wastes so that quantities, solubility, con- W.D.A.s owing to local circumstances e.g. the G.L.C. centration and other factors can be taken into consider- has insufficient landfill sites to meet its needs and ation to balance the interests of the water authorities combines incineration with heat recovery, distant dis- and waste disposal. It is with greater certainty now that posal to landfill by road and rail transfer stations and a site evaluation, properly conducted, to include hyd- because of its unique situation places a considerable rogeological and geological characteristics and assessed tonnage in barges via the River Thames to estuarial to be safe can be declared of its suitability to receive specified wastes. If hazardous wastes are to be included marshes for land reclamation. searching evaluation is necessary to determine a more 8. LANDFILL OF UNTREATED WASTES permeability, and porosity, apart from the toxicity 8.1 One of the principal reasons for at least 90% of assessment and the behaviour by interaction between waste handled by W.D.A.s going to landfill is the wastes. Downloaded from by IGNACIO GARCIA MARTINEZ on November 29, 2007 © 1983 Royal Society for the Promotion of Health. All rights reserved. Not for commercial use or unauthorized distribution.
  5. 5. 19 8.8 Methane generation from anaerobic decomposi- rate of while the intrusion of air is production kept at a tion of wastes has been known for many years but the minimum&dquo;. changing characteristics of modern refuse with higher 8.14 The current research work in the U.K. is the concentrations of cellulosic materials has focussed investigation of landfill techniques plus methane gener- attention on gas evolution that has significance and ation and control. This means that the future for landfill could be dangerous in certain circumstances or utilised of untreated wastes may have increased importance as pollution aspects and hazards from gas evolution are as an energy source. 8.9 The generation of landfill gases from decomposing overcome by engineering practices and the harnessing wastes is a distinct pollution hazard not yet fully of the wastes commercial energy becomes source as a a investigated or assessed although research work is reality. continuing in many countries. The gases produced are 9. LANDFILL WITH TREATED WASTES carbon dioxide, methane, nitrogen, oxygen, hydrogen, hydrogen sulphide although the principal constituents 9.1 Under this category falls shredded, pulverised and are carbon dioxide and methane. These gases vary in baled waste placed into landfill sites. Pulverisation is proportions due to the input waste, moisture content, conducted by high energy consuming hammer mills depth of fill and density and have shown a methane mounted on horizontal or vertical shafts or disc shred- percentage ranging from below 40 per cent of the total ders which cut and shred the wastes by guillotine gas evolution to over 60 per cent. The high concentra- action. Both methods have substantial reject materials tion of methane gases from a G.L.C. landfill site which cannot be processed and with the growth of obtained from the average of a six month period bulky waste the problems are exacerbated. This has collated in 1979 is shown in the following table :- caused interest in ’wet’ pulverisation using the revolv- ing Dano type drum which succeeds in breaking down the fibrous materials by the addition of moisture and by continuous agitation into fine and coarse products. A major advantage of the finished product is its potential use not only for land reclamation but also as a land- scape construction material. can be dangerous in concentrations if These gases 9.2 Baling of waste has slowly evolved as a means of buildings as they migrate and travel consider- to near improvement to visual and amenity standards in land- able distances depending upon the permeability of the fill. Initially it requires less space, has slower bacterial soil formation around the landfill site. They can also decomposition and is neater in handling. The bales can affect the water quality by degradation as they diffuse be self sustaining or restrained by wire ties with in different directions to be dissolved when in contact densities of 53/55 lb/3 achieved but unless the bales are with ground water. properly handled, unloaded without breakage, nudged 8.10 The danger of methane forming an explosive risk together to prevent large vertical voids, in-place density when in concentration of 5-15 per cent in air has will suffer as a consequence. resulted in personal injury and structural damage when 9.3 Treatment of wastes it is claimed is less attractive ignition took place. Case histories have been to insect pests, vermin, birds and is environmentally documented of how these events happened but was due more acceptable, better payloads from transfer stations to migration of methane from the proximity of landfill can be achieved and with baled waste conventional sites. Vegetation has also been affected by methane, transport only is necessary. trees, shrubs and root crops have either failed or been 9.4 Pulverisation is usually required in processing wdf inhibited in growth due to oxygen depletion caused by but for landfill purposes only reference to the differ- methane attack around the roots. ences in disposal costs (Table 3) reveals a high pre- 8.11 Having outlined the pollutant and other hazards mium must be paid. that may obtain by landfill the situation can be control- led by good engineering practice. A venting system 10. INCINERATION comprising of excavated trenches of sufficient depth width around the perimeter of the site between the nd 10.1 Municipal incineration of waste with some form ~andfill of heat recovery has been practiced for over 80 years. and virgin ground and filled with aggregate will There was a time when separation of salvageable allow the gases to disperse to the atmosphere freely. In materials prior to incineration was in vogue particularly addition a gas flare system can be installed and the during the 1920-40 period. However immediate post- gases harmlessly burned. If methane production in changing landfill is to be encouraged as a commercial energy characteristics of wastes, high standards war introduced under Clean Air Acts, labour difficulties, source then a more refined and engineered system is improvements in carrying capacities of vehicles for required. transfer operations, increased costs, lower income, all obtained from Mountain 8.12 Interesting results were tended to set in a decline. A revival in the early 1960s View, California, Landfill Site where methane recovery resulted in a new generation of direct incineration demonstrated as a commercial proposition for was plants some with heat recovery, others without. It energy purposes. What has emerged from this large involved high capital investment, maintenance and project is atmospheric interference is inversely propor- operating costs but militating against the advantages of tional to abstraction well depth, that an optimum good volume reduction was the availability factor so withdrawal rate can be determined, any higher rate that an alternative means of disposal was necessary in attempted means a less concentration of methane and emergencies. A study of incineration costs has shown a nitrogen increase. very sharp increase over landfill costs which has thrown 8.13 Further research work is continuing using a radial into jeopardy further construction of plants. flow model which measures landfill’s production and 10.2 Manufacturers have recognised these disturbing pressure changes caused by the withdrawal of gas can features and are trying to design plants that engineer be calculated, the landfill’s production rate and gas flow permeability. &dquo;The optimum recovery of methane is out problem areas to give a high availability factor. The present concept is flexibility to handle difficult wastes, achieved when the rate of withdrawal approaches the Downloaded from by IGNACIO GARCIA MARTINEZ on November 29, 2007 © 1983 Royal Society for the Promotion of Health. All rights reserved. Not for commercial use or unauthorized distribution.
  6. 6. 20 matched by appropriate grate designs, ability to with- 12.2 In recovery the encourage- evaluating resource stand thermal shocks, abrasiveness, satisfactory burn- ment at source by public participation for metals, glass out, acceptable chimney emissions, good controls, and waste oil at civic amenity sites can be carried out at easier maintenance, high availability. The design fea- minimum cost and risk but with maximum national tures tend to favour three shift operation and incorpo- benefit. The voluntary route is limited but to carry out rate automatic controls to reduce expensive manning resource recovery from the vast tonnage of municipal levels. waste discarded needs expensive capital investment. 10.3 With the realisation that domestic refuse has a The two demonstration plants sponsored by the D.O.E. c.v. approximating to one-third of good coal heat in association with W.D.A.s at Byker and Doncaster recovery as a permanent feature in a developing energy have been operating for up to two years but experi- crisis situation is proposed as a future option. enced difficulties requiring modifications to handling 10.4 It is difficult to reconcile European experience of systems. Even with income deducted from the sale of waste incineration with heat recovery with that of the wdf and other constituents the operational cost remains U.K. However the following table is significant :- high. Both plants are fairly costly to construct so that marketability of products is fundamental before initiat- Western from Refuse Europe (3) Energy Recovery In ing resource recovery as a disposal option which still requires a substantial landfill requirement for rejects and residues. Plastics are still not marketable as recy- cled materials owing to mixed grades being incompat- ible for re-use, they must be clean and free from all contraries, a condition not likely to be met after being thoroughly mixed and contaminated from collection to disposal point. Their main benefit is in wdf owing to their low ash content and high c.v. characteristics. 10.5 The success of heat recovery schemes depends 12.3 Experience of resource recovery plants around developing4 upon the acceptance of an industrial user in immediate the world have shown the problems of proximity to a permanent supply or a steam facility for mechanical plant and equipment to deal with a difficult district heating, factors not easily matched. Some exist- heterogeneous material like waste. Even now the prob- ing direct incineration plants with no heat utilisation lems have engendered ’second generation plants’ in are being investigated with a view to installing waste which original problems are hopefully eliminated. heat recovery boilers and using the hot gases to a 12.4 The choice of a complete plant is full of complex- nearby heat requirement. Calculations of installation ities owing to future market uncertainty. With alterna- costs of boiler and ancillary equipment, running costs tive sources of energy taxing the Government’s mind and likely income for heat supplied give very favour- the brightest aspect in resource recovery is wdf as a able conditions especially if inflation continues and future complementary fuel with coal. energy costs rise accordingly. 12.5 However, landfill of untreated wastes properly 10.6 Incineration of waste with heat recovery in engineered can extract energy in the form of methane favourable circumstances will have to be evaluated as a gas and this option must be considered as a possible future disposal option to exploit energy shortages, source. accelerating costs and utilisation of constituents e.g. metals. 13. HAZARDOUS WASTE DISPOSAL 13.1 Although much public apprehension has been 11. COMPOSTING shown in the past to hazardous waste disposal the 11.1Many mechanical systems for producing compost House of Lords Select Committee after examining a from crude wastes have been developed but not suc- considerable volume of evidence concluded that the ceeded in the U.K. because of farmers reluctance to Country must come to terms with the hazards of waste purchase the products. Also the heavy metal content of disposal. They accepted that commendable effort had domestic refuse may inhibit plant growth or cause to, been directed to controlling its passage from ’cradle controls4 uptake in certain vegetable or root crops. There is of the grave’ but made reservations for stricter course the problem of reject materials which may and higher standards to be introduced. This would give contain 6 per cent plastics, 10 per cent metals, 10 per the public more confidence in positive protection of the cent glassware, and 3 per cent textiles by weight and are environment in which they have their being and wish to undesirable in compost preparation. preserve its wholesomeness for posterity. 11.2 The crude wastes can be blended with additions 13.2 In the past industrial waste disposal including of sewage sludge but adverse marketing conditions in hazardous materials have been handled mainly by the the U.K. has caused this disposal option to decline. private sector, this is recognised, but for the future joint Again installation and operating costs are high and with facilities are recommended so that co-disposal of a lack of purchasers it becomes disposal by landfill a domestic refuse is utilised with many liquid wastes more expensive method in comparison with direct accepted subject to all possible safeguards relating to landfill of untreated wastes. site selection and fitting the correct climatic, geological and hydrogeological conditions. 12. RESOURCE RECOVERY PLANTS 13.3 The proper disposal route must always follow the best practicable option not necessarily the cheapest and 12.1 The recovery of useful constituents from waste &dquo;sensible landfill is realistic and an ultra-cautious has been promoted for many years unfortunately indus- approach to landfill of hazardous and other types of trial depression and lack of markets for products has waste is unjustified&dquo;. caused a serious decline. Although W.D.A.s are 13.4 A number of additional restraints may be required to consider reclamation and re-use of wastes required to identify more clearly the nature of the under the C.O.P. Act 1974 unless stable markets exist wastes produced so that better in-house treatment or offering reasonable prices it is not justified economi- re-use or reclamation of materials may be prescribed or disposal option. cally as a continued page 24 on Downloaded from by IGNACIO GARCIA MARTINEZ on November 29, 2007 © 1983 Royal Society for the Promotion of Health. All rights reserved. Not for commercial use or unauthorized distribution.