Waste management in Copenhagen: Principles and trends

Waste Management & Research (1991) 9, 239-258

WASTE MANAGEMENT IN COPENHAGEN : PRINCIPLES AND TRENDS* lb Larsen and Kit Borrild Miljokontrollen, Stormgade 20, 1555 Copenhagen V, Denmark (Received 10 October 1990 and accepted in revised form 28 January 1991)

The increase in volumes of waste, and the difficulties of finding suitable locations for landfill sites within the borders of Copenhagen municipality, along with the need for treatment of oil and chemical waste, resulted in the erection in the early 1970s of two large waste-to-energy plants and a large centralized plant for the treatment of oil and chemical waste . Ten years later, however, it became evident that the then structure was not sufficient to face rapidly emerging problems . A number of pollution cases in Denmark which emerged during the early 1980s, proved that oil and chemical waste was being transported illegally to landfills instead of being disposed of in compliance with the obligatory system, thus becoming a threat to groundwater and drinking water supplies in Copenhagen. At the same time, waste-to-energy plants were facing pollution problems such as the emission of dioxin and large quantities of hydrochloric acid, which contribute to acidification and forest death . As a response to the increasing problems in relation to both waste incineration and deposits, new regulations from the Ministry of the Environment allowed future sanitary landfills to be located only near the coast or in areas documented to be composed of an impermeable layer of clay . New regulation also defined conditions for flue gas cleansing . However, it was clear that pollution problems combined with increases in volumes of waste called for a much firmer administration and a stronger influence on the waste flow . From February 1989 the municipalities have undertaken the obligation to assign all waste producers the means to dispose of their waste . How Copenhagen municipality has solved the problems is discussed . Key Words-Waste management, waste incineration, hazardous waste, recycling, cleaner technology, waste minimization, legislation

1 . Copenhagen municipality The municipality of Copenhagen comprises the central parts of Greater Copenhagen . Until recently, administrative tasks were shared between Copenhagen municipality and Greater Copenhagen Council, which took care of certain regional issues within the geographical area of north-eastern Zealand . On 1 January 1990, however, Greater Copenhagen Council was abolished and henceforth Copenhagen municipality has been responsible for all municipal and regional tasks within the geographical borders of the municipality (Fig . 1) . Geographically, the municipality is rather small, covering a mere 8820 ha (21,794 a) . There are 467,850 inhabitants, which is about half the population within the urban area

* Based on a presentation made to the Waste Management Plans of Cities and Conurbations Congress, Vienna, Austria, 3-6 October 1989 . 0734-242X/91/040239 + 20 $03 .0010

©1991 ISWA



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Fig . 1 . Copenhagen Municipality boundary and catchment areas of waste-to-energy plants . Lighter shading shows the Vestforbraending catchment area (VF), and the darker shading shows the Amagerforbrxnding catchment area . Key : . . . . Copenhagen Municipality boundary ; ∎, Avedere Holme deposit (AV) .

named Greater Copenhagen . The population is constituted by relatively many elderly and young people, while the age group 25-66 years is relatively few in numbers (Fig . 2) . The city is characterized by a considerable proportion of older and small-size housing . The average household in Copenhagen municipality counts 1 .7 persons . Housing consists mainly of residential blocks, while single-family houses constitute approximately only 7% of the households . There are 20,294 single-family houses and 278,482 households . A considerable proportion of housing is old and obsolete ; The majority of apartments have no chutes . Small-sized living-quarters and the large number of residential blocks are the reasons for an average household's income being less in Copenhagen than the national average, and considerably less than a number of neighbouring suburbian municipalities . Average gross income is 130,000 Danish kroner (approximately U .S . $18,000), while comparative figures in adjoining residential suburbs is as much as 220,000 kroner (approximately U .S . $31,000 on average . The national average gross income is 170,000 kroner (approximately U .S . $24,000) .

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Fig . 2 . Age class distribution in Copenhagen and Denmark . Key : El = 1979 ; ∎ =1988 .

2 . Municipal management and environmental administration in Copenhagen

The supreme authority of the municipality of Copenhagen is the City Council, which comprises 55 members . The daily management of Copenhagen is in the hands of the municipal corporation, with a Lord Mayor and six mayors, who are all elected by the City Council . The mayors are each responsible for the administration of business relating to specific areas . Environmental protection belongs to the corporation's 5th department, comprising gas and electricity services, water supply, food inspection, and environmental inspection (Miljekontrollen) . The corporation's 5th department is headed by Charlotte Ammundsen, entitled Mayor for the Environment . Miljekontrollen (the local agency of environmental protection) has a staff of 125 allocated as of 1 January 1990 into eight offices with the following concerns : A D1 : administration ; A D2 : disinfestation and other biological concerns ; A D3 : noise control and physical planning ; A D4 : air pollution and risk management ; A D5 : waste management ; A D6 : soil pollution ; A D7 : water pollution ; A D8 : inspection planning. Within the Danish municipal structure, Copenhagen has an exceptional position, as it is not only a primary municipality, but also a county . Thus, Miljekontrollen is in charge of tasks relating to environmental protection at municipal as well as at county levels . Miljekontrollen does not undertake the operation of waste treatment facilities . This has been handed over to intermunicipal partnerships (waste-to-energy plants, waste water plants, landfills, receiving stations for oil and chemical waste, recycling stations,



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etc .) or concessionary companies (collection, sorting, etc .) The handing over of tasks to intermunicipal partnerships or concessionary companies is primarily due to the fact that these companies operate within a larger geographical area than Copenhagen municipality . Daily contact between the municipality and the companies lies with Miljekontrollen . Street cleaning belongs under the corporation's 4th department . 3. Establishing a comprehensive waste management plan for Copenhagen The basic structure of the present waste management system in Copenhagen was founded in the early 1970s, where two large waste-to-energy plants were erected in response to increasing difficulties of finding suitable locations for landfill sites . During the incineration process, a volume reduction to about 6% of the original volume was obtained . Likewise, the generated energy could be used for district heating . The plants were first of all built for the treatment of household waste . According to the Danish Environmental Protection Act, all municipalities were obliged to establish collection schemes for household waste from residential areas with more than 2000 inhabitants . As to commercial waste, this was until early this year considered as "free waste" . Private enterprises were obliged to secure for themselves the environmentally safe removal of their waste . In practice this meant that the waste could be handed over to commercial operations, who had been granted the permission to treat or deposit waste (with approval by the Danish Environmental Protection Act), or to operations established before the coming into force of the Act of 1974, which had remained unchanged since that date . Thus, commercial waste could either be handed over to waste-to-energy plants, or sent to private landfills, of which until recently there were a considerable number within and immediately outside of Greater Copenhagen . The two waste-to-energy plants were placed so that they were conveniently located for the entire area of Greater Copenhagen, hence why the borderline between the catchment areas of the two plants runs straight through the Copenhagen municipality (Fig . 1) . Amagerforbranding was placed on Amager, within the borders of Copenhagen municipality . The catchment area is the island of Amager, Hvidovre and Frederiksberg municipalities, and two thirds of the Copenhagen municipality . Amagerforbrxnding is run by a partnership, the partners being Copenhagen, Drager, Frederiksberg, Hvidovre and Târnby municipalities . The partners are committed to delivering all household waste to the plant . (Part of Copenhagen municipality's household waste belongs to Vestforbrwnding .) In addition to delegates to the general assembly, Copenhagen municipality is represented in the partnership by two out of six board members . Raising of loans, etc . must be approved by all partners' local councils . In recent years, the plant has incinerated about 280,000 t y - ', of which 200,000t derives from Copenhagen municipality . Approximately 70% of all registered waste is household waste . The plant has been connected with the existing district heating system in Copenhagen . Vestforbrcending was placed west of Copenhagen municipality, and services the municipalities north and west of Copenhagen, and one third of Copenhagen municipality . VestforbrTnding is similarly a partnership, made up by Copenhagen, Ballerup, Birkert d, Farum, Gentofte, Gladsaxe, Glostrup, Herlev, Ledoje-Smorum, LyngbyTâbxk, Rodovre and V erlese municipalities . The partners are committed to delivering all household waste to the plant . In addition to delegates to the general assembly, Copenhagen municipality is represented by one board member out of 12 . The plant's capacity is about 360,000 t y - ', of which usually 75 000 t derive from Copenhagen municipality . Approximately 70% of all registered waste is household waste . In



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connection with the erection of the plant, a local district heating system was established in neighbouring municipalities (Fig . 3) . In association with the two waste-to-energy plants new sanitary landfill sites were established for clinker and fly ash, and non-combustible waste . The sanitary landfills were placed in the heart of the region, in former gravel pits . Vestforbrxnding owned a sanitary landfill in Ganlese, while Amagerforbra :nding had access to a sanitary landfill in Uggelese . In 1964 the collection of household waste in Copenhagen was handed over to the concessioned company Renholdningsselskabet of 1998 (R98) . The articles of concession are the foundation for a regulation on household waste, and they mention some overall guidelines for transportation of refuse and lavatory waste as well as other waste categories, and in addition certain conditions as to the municipality's right of inspection, financing, loan raising, etc . R98 is a private foundation . The supreme authority is given to a council with 67 members, of whom 13 are appointed by the Copenhagen municipal council. Thirty-four of the council members represent landowners . The company collects waste from the catchment areas of Amagerforbrxnding and Vestforbrxnding within the Copenhagen municipality . In addition, the company collects "free" commercial waste through its commercial section, RenoFlex, in open competition with other carriers . The collection and treatment of hazardous waste has a separate structure, initiated in the 1970s . During the 1960s, hazardous waste was fed through a pump station (at Klevermarken) into the Sound, and some of it was incinerated and deposited under rather unsatisfactory conditions in a former test purifying plant at Damhussâer . In 1971, the municipality of Copenhagen and the federation of muncipalities in Denmark agreed to establish a large centralized plant for the treatment of waste . The plant -Kommunekemi-was erected in Nyborg on the island of Funen . From 1972 it was prepared to receive oil waste, and from 1976 chemical waste . A regional receiving station was established in Copenhagen municipality in 1972 to receive waste from all private enterprises in Greater Copenhagen . From here, the waste is carried by rail to Nyborg . A separate Act on oil and chemical waste, passed in 1972, together with instructions of 1972 and 1976, prescribed obligitory delivery of hazardous

Fig . 3 . Direct heating system for Greater Copenhagen area, 1988 .



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waste to the receiving station by private enterprises . In 1982, the receiving station in Greater Copenhagen acquired a status as an interdependent partnership with a board elected by the partners . The partners are Copenhagen and Frederiksberg municipalities, and the municipalities in outer Copenhagen county . Copenhagen municipality has two out of five members on the board . Daily operations and management of the partnership is headed by I/S Amagerforbrxnding . In 1988, the receiving station accepted about 9000 t of waste from private enterprises in Copenhagen municipality . Exemption from obligatory delivery may be granted if the waste is regenerated for recycling . As delivery fees are rather high (4000 to 5000 kroner, or U .S . $570 to U .S . $715), the establishment of private recycle companies has been encouraged . In particular, solvents, dyes, photographic liquids and certain heavy metals are being recycled . Large quantities of waste oil are recovered as fuel oil . Since for the citizens it was rather inconvenient to take hazardous waste to the distant receiving station, an additional scheme to deliver waste from households to 73 hardware stores throughout the city was initiated in 1979 . Today, about 34 t of waste is delivered in this way every year . From the early 1970s, Copenhagen municipality has thus had a modern and efficient organization and structure for waste management . Over the last 10 years or so, however, it has become evident that the present structure has not been sufficient to cope with problems rapidly emerging in the wake of both increasing waste volumes, and increasing use of polluting and synthetic matters in production and consumption . In the following, we shall discuss some of these problems, as well as reactions to them . 4 . New problems in waste management A great deal of commercial waste, largely from demolition and construction, and residues from waste incineration have been brought to sanitary landfills in the region . The planning of landfill capacity and situation has been carried out by the Greater Copenhagen Council . Both existing and planned landfills have been located in interior parts of the region, in former gravel pits or the like . The new sanitary landfill sites were indeed laid out with better consideration for the environment than the older ones . Membranes covered the ground and the sides, and there were systems for leachate control and monitoring etc . A number of pollution cases in Denmark which emerged during the early 1980s, proved however that oil and chemical waste was illegally being carried out to landfills, instead of being brought to the above-mentioned receiving station . As the illegal cases proceeded, it became clear that action to restrict disposal had to be taken . As this public debate in itself increased the deliveries being made to the Greater Copenhagen receiving station by 30%, it was obvious that considerable amounts of hazardous waste had been and probably were still being transported illegally to landfill sites or other places, instead of being disposed of in compliance with the obligatory system . Most recently leachate has been observed in 1986 at Vestforbrxnding's newest sanitary landfill in Ganlese . Drinking water supplies in Copenhagen are entirely dependent on the groundwater in those same areas . Since even the best laid out landfill sites appeared to provide no guarantees against leachate through to the groundwater, there had to be taken some sort of action towards the future localization of sanitary landfills . In 1985, the case ended up at the supreme appeal court for environmental issues . Miljoankenxvnet, which maintained a recommendation by the Danish Environmental Protection Agency, Miljostyrelsen, concluding that all projected landfill sites in,



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for example, former gravel pits, were to be cancelled . In future, sanitary landfills would only be allowed to be located near the coast or in areas where careful analyses would document an impermeable layer of clay . This ruling brought about the collapse of regional landfill planning, putting great pressure on existing waste-to-energy plants and sanitary landfills, which neither could possibly meet . Waste-to-energy plants had to introduce quota schemes for their regular customers, and reject new ones . Despite the fact that the customers were aware of the quotas, it has been estimated that Amagerforbrxnding alone refused requests corresponding to 30-40,000 t y - ' . The waste was instead transported to sanitary landfills at distant locations on Zealand and neighbouring islands . At the same time, problems with illegally deposited waste were increasing, and waste was piling up in many private enterprises . By 1988, Amagerforbrxnding's sanitary landfill, located in Uggelose, had filled up, and henceforth the plant had no place to deposit its residues and noncombustible waste . Vestforbrxnding had a contract with a private sanitary landfill in Sengelose, but again there was limited capacity to last for only a short period of time . This development took place simultaneously with a rapid increase in waste volumes . Between 1985 and 1987 the total waste volume in Copenhagen municipality increased by about 12% . The waste-to-energy plants in Copenhagen had to find temporary capacity in neighbouring regions. The Minister for the Environment had to participate as a mediator before an agreement could be reached with the waste-to-energy plant I/S KARA in Roskilde county, west of Copenhagen, which had still some landfill capacity available . In return, Roskilde county is allowed to deposit a similar volume of waste at the new Greater Copenhagen sanitary landfill, once this has been brought into use . The establishment of a new, large sanitary landfill in Copenhagen was one of the initiatives that had to be immediately implemented . At Avedore Holme, immediately outside of Copenhagen municipality (Fig . 1), the conditions for coastal deposits were met ; there was a fair distance from major residential areas, and good highways leading there . Approving of the locality, however, was a cumbersome process, because physical planning in Denmark contains a number of hearing provisions and appeal opportunities, and also because sanitary landfills are rarely met with enthusiasm by the locals . The site was brought into use later in 1989 . Its capacity is 2 million m3 (Fig. 4) . The site is expected to have sufficient capacity to receive waste from the catchment areas of Vestforbrxnding as well as of Amagerforbrxnding for 5-10 years . Like the sanitary landfills, the waste-to-energy plants suffered heavily from the increasing volumes of waste . In addition, there was a growing supply of "free" waste from private contractors and waste producers in step with the capacity problems of the landfill sites . At the same time, the waste-to-energy plants were facing new pollution problems, parallel to those of the sanitary landfills . The debate on the pollution problems of waste-to-energy plants gathered momentum as a consequence of the Seveso accident and the ensuing debate on dioxin . A report worked out by the Danish Ministry for the Environment in 1984, proved that waste-toenergy plants were one of the major sources of dioxin pollution in Denmark . The problem lay not so much with the plants in Copenhagen, as they were technically up-todate, had continued operation, and high temperature incineration (on average 950°C) . Despite the fact that dioxin emission per ton was consequently low, the absolute size of the plants-being the two largest incineration plants in Denmark-meant that 25% of the dioxin emission from waste-to-energy plants in Denmark was estimated to come from these two plants alone . Forest death was the next major issue to appear in the public debate . Waste-to-energy



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Fig . 4 . The deposit at Avedere Holme, established on what was formerly the sea bed, which consists of about 6 m of moraine clay membrane .

plants emit large quantities of hydrochloric acid, thus contributing to acidification and forest death . A reduction of the acid content in the flue gasses required flue gas cleansing and/or reduction of the Cl-content in the waste . A new regulation from the Ministry for the Environment in 1985 imposed an obligation on all old incineration plants to request approval, and in a set of guidelines passed in 1986 the Ministry set up a number of requirements for such approvals . The guidelines define conditions for flue gas cleansing, incineration temperatures, retention periods, process control, supportive oil burners, and 24-hour operation. The first flue-gas cleansing plant has now been installed at Amagerforbrxnding (Fig . 5) . It is a so-called semi-dry plant, where the flue gas is cleansed by means of lime water . This is dosed from the top by a reactor with an atomizer . The lime water reacts with a .o . hydrogen chloride, and the hot flue gas makes the water evaporate so that the residue is a dry product . This is removed, together with the fly ash of the flue gas, in a bag house filter . Experience after nearly 1-year's operation shows that the flue gas after cleansing contains :

< 100 mg m -3 hydrogen chloride (HC1) < 1 mg m -3 hydrogen fluoride (HF) On the basis of experience from operation with this plant, the remaining incinerators at Amagerforbrxnding as well as at Vestforbrwnding are to have flue-gas cleansing installed . The requirements for flue-gas cleansing add to the waste-to-energy plants' capacity problems . With an additional process link in the incineration process, obviously the risk for operation stops is similarly heightened, thus implying decreasing capacity . The capacity reduction due to flue gas cleansing is estimated to be approximately 5% . During the flue-gas cleansing process, calcium is added as a means of tying down the chloride content of the gases . The addition of calcium increases the volume of residues,



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and hence the pressure on sanitary landfills . The semi-dry method is expected to entail an increase of about 150% in the volume of residues from flue-gas cleansing, compared with cleansing by means of electrostatic precipitation alone . Once flue-gas cleansing has been fully installed at Amagerforbrxnding, it is estimated that there will be about 23,000 t of residues from flue-gas cleansing a year . Increasing pollution problems in relation to both waste incineration and deposits require much firmer administration and a stronger control by the authorities on waste flow . Firstly, hazardous waste must be sorted from the waste . This calls for a heightened control to prevent illegal supplies of oil and chemical waste reaching the waste-to-energy plants . Activities in this field have been centered on better inspection, the establishment of collection schemes etc . The opportunities of private enterprises to legally dispose of their hazardous waste have been simplified . Similarly, action has been taken against substances that contribute to the formation of hazardous combinations in waste-toenergy plants-primarily chloride compounds . Activities in this field concentrate on PVC waste, which is estimated to cause about 50% of the chloride content, and food waste which contributes with approximately one third of the chloride content . Secondly, waste volumes should be reduced . This is to be done through enforced action towards "cleaner technologies" and increased recycling . Renholdningsselskabet of 1898 has initiated a number of schemes towards that end, in cooperation with Miljokontrollen, and likewise a waste management plan . Thirdly, a far more efficient separation, sorting and allocation of the waste must be set up, so that fractions such as soil and non-recyclable demolition waste need not be brought to sanitary landfills . The waste may instead be carried to so-called inert landfills with less requirements as to preventive measures against leachate . Such landfills may be established faster and more easily than sanitary landfills. Similarly, the remaining waste has to be separated more carefully into combustible and non-combustible waste, so that débris, glass, metal and other non-combustible waste does not go to waste-to-energy plants, while waste that may contribute to energy recovery and undergoes significant volume reduction during the incineration process should not be deposited in landfills . If non-combustible waste is brought to the waste-to-energy plants it will recur among the clinker and will need depositing in the sanitary landfill, while a part of the waste, if sorted before incineration, may instead be forwarded directly to an inert landfill . The problems can be solved by establishing specific collection schemes and pre-sorting



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plants at the waste-to-energy plants, by setting up a tightly woven pattern of recycle stations, which apart from a separate collection of recyclable fractions will secure separation into combustible and non-combustible waste, and by setting up an efficient tax structure for the waste-to-energy plants, which will induce private enterprises to carry out pre-sorting themselves . As a consequence of, for example, the tax system, a number of private reloading stations have emerged in recent years . Securing the effectiveness of the above initiatives is the pivotal aim of those comprehensive changes and development projects being undertaken in Copenhagen in cooperation between Miljokontrollen and the intermunicipal partnerships . These initiatives will be discussed in the following . However, it remains certain that waste incineration can not be dispensed with for many years to come . On the contrary, capacity problems are so immense that, despite the expected subsequent reduction of waste being supplied to waste-to-energy plants, it will be necessary to expand the plants' incineration capacity . It is estimated that the initiatives will lead to a reduction by 60,000 t of the waste volumes for incineration over the next 10 years, and in addition there will be a marked reduction in the volume of noncombustible waste for deposits in landfills . However, the accumulated capacity deficit, combined with the reduced capacity caused by, for example, the installation of flue-gas cleansing and an improved presorting of waste delivered at landfills, will most likely lead to a need for increased incineration capacity . In 1988, it was decided to expand Amagerforbrœnding with a fourth incinerator, having a capacity of 12 t hr - ' . The incinerator will be set into operation in 1992 . The expansion of waste-to-energy plants and the decision to maintain this method in future waste strategies, makes impending demands on the lay-out of the joint environmental protection and resource conservation strategy . The greenhouse effect, acid rain, etc . imply that the atmosphere must not be polluted by increased volumes of incineration residues . An essential part of the planning will therefore be to ensure that waste-toenergy incineration replace as far as possible the extensive burning of other fossil fuels . The use of waste as a source of energy must, from a global point of view, be seen as more appropriate than further emission of carbondioxides into the atmosphere from fossil stocks . The precondition is that waste-to-energy plants are set up and operated as primary energy supply plants . The plants must be set up as efficient power and heating plants . Subsequently the fourth incinerator at Amagerforbrœnding will be prepared for both power and heating production, and similarly the other incinerators will later be reconstructed towards that end . However, the role of waste-to-energy plants as efficient energy suppliers entails further requirements to the quality of waste being accepted . The waste must have highest possible combustion value, first of all through pre-sorting of non-combustible waste and items that will reduce the combustion value . The non-combustible waste has been dealt with above . Waste that reduces combustion value is primarily food waste, with a combustion value of about one third of the average for household waste . As mentioned above, food waste is at the same time one of the dominant sources of chloride pollution . The energy content of the food waste may instead be used through combined biogas and compost production (see discussion below) . On the background of experience from obtainable combustion values, incinerators may in the future be designed for incineration at the highest possible combustion value .



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5 . Principles of and trends for waste planning in Copenhagen 5 .1 Legal foundation The problems of waste management discussed above are obviously not unique to Copenhagen, although they have generally influenced the development within this sector . A notable consequence is the fact that in recent years the legal foundation for regional and local waste management in Denmark has undergone radical changes . The legal foundation of waste planning is made up of three legal acts : (1) The Environmental Protection Act deals with waste that may create a nuisance, unhygienic conditions, etc . It also contains rulings concerning approvals and inspection with waste-to-energy plants and landfills, and also deals with decisions on waste planning (Act on Environmental Protection no . 68, 24 January, 1989) . (2) Oil and Chemical Waste Act deals with waste that entails hazards to health and environment (Act no . 178 on Disposal of Oil and Chemical Waste, 24 May, 1972) . (3) Recycling Act deals with waste characterized by immediate recoverable features . (Notice no . 532 concerning Act on Recycling and Minimization of Waste, 16 October, 1984) . 5 .2 Principles of waste management in Denmark (1) Optimizing the infrastructure of waste disposal : Until 1982, waste regulation was directed at treatment and disposal of waste with the aim of optimizing the infrastructure by dimensioning and locating the waste treatment facilities in relation to the composition of the waste volumes and their regional distribution . (2) Minimizing waste volumes : In 1982, an amendment to the Act on Environmental Protection ruled that regional and local planning of the waste disposal was to be carried out, so that a survey of each waste fraction would be the basis for efforts to enhance recycling and reduce the need for incineration and landfill deposits . The first waste management plan for Copenhagen was passed in 1990 . The essential principles of the plan will be discussed in section 5 .3 . The next decisive amendment to the Act on Environmental Protection was enacted in 1986 when legal authority to determine rules for waste disposal schemes for all waste fractions from all waste producers was introduced . The impending capacity problems, and the ensuing problems for private enterprises in disposing of the waste made the Folketing enact regulations on a municipal assignment duty . (3) Assignment and utilization duties : In February 1989, an instruction on the new regulations on waste disposal were publicized . The municipalities are thus now under the obligation to assign all waste producers the means to dispose of their waste . Previously, the municipalities' obligations, as described above, concerned only household waste . All are exempted from assignment duty except residues from power plants, and certain forms of special waste . Simultaneously with the assignment duty, a utilization duty was introduced, parallel to the collection and disposal schemes established by the municipalities .

• House owners, commercial activities and institutions, etc . must utilize the assigned disposal facilities . (However, the municipality must exempt enterprises from the obligation to utilize municipal schemes on recyclable waste, if they can prove that this waste is already being delivered for recycling .)



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• In addition, the Act on Recycling ruled that municipalities must initiate schemes for collection of paper and glass from residential areas, paper and cardboard from commercial activities, and food waste from restaurants and canteens . These schemes had to have been set up by 1 January, 1990 .

The municipal assignment may be collection schemes, conditions for specific delivery locations, utilization of authorized carriers, etc . The instruction specifies that the schemes may be set up separately for each individual material fraction . Private enterprises may be prescribed to undertake necessary sorting and separate handling of individual material fractions, and to supply all required information concerning the waste and its composition . Thus, the concept of "free waste" has disappeared from the waste management sector in Denmark . It is now possible to build up nuanced waste management systems, where individual waste flows from all waste producers are put together on the basis of an aim to optimize waste treatment and minimize waste volumes . Simultaneously, a general waste tax of 130 kroner per ton (U.S . $20) has been introduced as an incentive to recycle waste, and to reduce waste volumes . Subsequently, a number of regulations have been set up to promote the development of clean technology . Terms are now given to private enterprises to reduce pollution to an environmentally acceptable level, and may be revised every 8 years if new, less polluting technologies appear . In the Act on Chemical Substances and Products an amendment has been passed, according to which the use of environmentally hazardous substances or products may be limited or entirely prohibited, if less polluting substances or materials become accessible . Finally, support programmes to encourage the development of clean technology have been set up .

5 .3 Principles of waste planning in Copenhagen

The waste management plan for the municipality of Copenhagen was, as appears from the above, to satisfy several objectives . • Hazardous waste must be separated from the waste disposed at waste-to-energy plants and sanitary landfills, and afterwards be recycled or treated at specialized facilities . • The volume of waste to waste-to-energy plants and deposits must be reduced through the introduction of cleaner technologies or recycling . • The remaining waste must be effectively separated into combustible/non-combustible waste to optimize the utilization of waste-to-energy plants, sanitary landfills and inert landfills . The waste-to-energy plants must be designed for maximum energy recovery . 5 .3 .1 Hazardous waste

With an aim towards securing maximum efficiency, Miljekontrollen set up a "priority programme" in 1987, in cooperation with the waste-to-energy plants . The project sought to clarify what priority should be given to measures against various substances to secure efficient environmental protection . The project was concluded in June 1989 . The implementation of initiatives did not, however, await the conclusion . Addressed towards households there now exists, as mentioned above, a scheme for collection through hardware stores, where citizens may deliver their hazardous waste . In 1987, a specific campaign towards discarded batteries was started in cooperation with Amagerforbrxnding . A massive information campaign-including a cartoon for use in



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schools about "Bernie Battery"-was launched . Agreements were made with major provision shops, photo shops and others to allow citizens to deliver their discarded batteries there . Some 400 shops are now involved in this scheme . In 1988, about 50 t of batteries were collected, or some 17% of the assumed potential . The disposal facilities for oil and chemical waste are being further expanded, as the recycle stations being established (dealt with in further detail below) will accommodate oil and chemical waste as well . In 1990, a scheme for the periodical collection of hazardous waste from all neighbourhoods was established in cooperation with R98 . A specially constructed vehicle visits all parts of the city four times a year . Provisional experience from the above scheme seems to indicate that there were still considerable amounts of hazardous waste not being collected through any of the above schemes . Private enterprises are, as mentioned, under the obligation to deliver their waste at the Greater Copenhagen receiving station for hazardous waste . There has, however, been ample reason to believe that not all enterprises have disposed of their waste legally . Control over the delivery of waste has therefore been intensified . A new system for registration has been established, through which Miljekontrollen may immediately record enterprises that do not deliver their waste, or who cut the deliveries of oil and chemical waste at the receiving station . At the same time, Miljekontrollen has carried out a number of trade campaigns, where all enterprises within a given trade are being visited to elucidate the handling of waste . For example, an analysis carried out in 1985-86 at garages in Copenhagen showed that 43% of organic solvents (31 t y - ') and 51 % of the rust preventives (15 t y - ') were disposed of illegally . Some of the illegal transactions are undoubtedly due to the difficulties of delivering the waste at the receiving station . In 1988, a voluntary collection scheme for packed oil and chemical waste was subsequently introduced, allowing private enterprises to have their waste picked up at their address, at a modest additional cost . However, this scheme has only had limited success . During the last 9 months of 1988 a mere 240 t were collected, possibly due to inadequate information about the scheme . From 1992, the scheme will be expanded to embrace also unpacked oil and chemical waste (waste from oil separators, degreasing baths, dye baths, etc .) . Collection schemes are expected to be made obligatory . Special schemes are being planned for a number of separate fractions of hazardous waste. Among these we might mention the following : Hospital waste : A regulation has been passed, obliging all producers to affiliate themselves with an established collection scheme . There have been problems with securing sufficient incineration capacity for the treatment of this waste . A temporary incineration scheme has now been established at Amagerforbrxnding . This plant has simultaneously been expanded with a herd for hospital waste in an existing incinerator . Likewise, Vestforbrxnding has decided to mount a new specialized incinerator for special waste . Until this incinerator has been set into operation Vestforbrxnding has been permitted to incinerate 3500 t of hospital waste a year, on certain conditions. CFC : A regulation has been passed to secure the collection of used CFC . Private enterprises are required to collect their used CFC at repair or dismounting of cooling systems, soil heating plants, etc . At R98 there will be collection facilities for the waste. Terms have been made for dry cleaning establishments and other trades using CFC as detergent, degreasing agents etc ., to improve collection of CFC . The terms extended to dry cleaning establishments have been given on a concurrent dialogue with the trade association, and the establishments were notified in summer 1989 . R98 has also recently



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started test drainings of used refrigerators, and a draining scheme is planned in connection with the establishment of recycle stations (see below) . Hg: Mercury waste has many sources : thermometers etc . from hospitals and the primary health sector, sludge from amalgam fillings at dental clinics, fluorescent tubes, back-pressure machines in heating plants, etc . Today, control of quicksilver content in waste water due to the municipality's 400 dental clinics is being set up . It is expected that 15 k of Hg a year may be traced back to dental clinics alone of the Dental College, of 250 chairs . An alarmingly high quantity of quicksilver has been found in their waste water . Orders to buy efficient filters at the dental clinics are now being formulated . R98 has implemented a collection scheme for fluorescent tubes from major office and shop areas etc ., and a registration of remaining Hg-back-pressure machines has been carried out . Regulations, imposing on private enterprises to deliver quicksilver waste through an obligatory collection scheme, are being worked out . R98 has initiated a project to be established at regeneration plants, for which applications of financial support have been submitted to the Danish Ministry of the Environment . As mentioned, it is also crucial that sources of chloride pollution in the waste be reduced to prevent acidification during the incineration process . The largest amount of chloride stems from PVC (52 per cent of the chloride content) . In 1987, Miljekontrollen carried out an experimental sorting scheme, in conjunction with R98 and Vestforbrwnding, in order to identify trades in Copenhagen with large amounts of PVC waste . The survey pointed out among other producers as flooring suppliers, office suppliers, plumbers, electrical appliance businesses and upholsterer's workshops (car seats) . On the basis of the survey, regulations will be worked out towards a systematic collection of PVC-waste from major PVC sources . It has not yet been clarified whether the waste may hereafter be reused . Citizens may deliver their PVC waste in a separate container at the recycle stations described below . It is not likely that citizens will be able to evaluate whether or not plastic waste contains PVC, so instead a number of products that are typically made of PVC, are assigned to the container . Vestforbrwnding intends to announce to its customers that PVC waste will no longer be accepted . The second largest source of chloride pollution in the waste is food waste (35%) . Separate collection of food waste is for various reasons a suitable waste strategy . In the following, we shall expand on this theme . 5 .3 .2 Waste reduction and recycling There is hardly any doubt that despite all initiatives towards recycling, we shall experience large problems in the waste management sector, if the generation of waste is not reduced . Copenhagen municipality is therefore very much aware of the fact that procurement of cleaner technologies is a crucial element in its waste policy . The municipality's activities to that end are concentrated on a policy of tax instruments as well as specific initiatives directed at individual trades and enterprises . Efforts will be primarily geared towards "trade campaigns", where all enterprises within an individual trade are dealt with . Through this activity it will be possible on the one hand to get time to obtain an idea of production conditions for the trade and its opportunities for waste minimization beforehand, and on the other the simultaneous action towards a number of similar businesses will provide a practical insight into whatever waste production is unavoidable . A survey of the efforts to promote cleaner technologies has been given in an article for the ISWA conference on cleaner technology in Geneva 1989 (Olsen & Larsen 1989) . As regards recycling initiatives, a set of principles has been determined . The aim is to



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be able to produce quality products that can on a long-term basis compete with primary products . It is our belief that this can be obtained only through sorting-at-source . In the waste management plan for Copenhagen, central sorting plants will therefore first play the role as control, and second as screening instruments . The selection of individual fractions for separate sorting collection and treatment will hereafter be made on an evaluation of the quality, accessibility of pre-sorted materials, and the environmental and resource preserving effect . In the following, the efforts towards household waste and commercial waste will be dealt with separately . 5 .3 .2 .1 Household waste . The collection of recyclable materials from households takes place at three geographical levels : in the household, in the neighbourhood and in the district . In the households the fraction considered most essential to obtain highest possible collection effect must be collected, and simultaneously the waste fraction should make out a significant proportion of the waste volume . It is not considered a realistic objective to establish a more complicated collection system than a "double-bag system" . The separation into two fractions will be kept at the realistic level . The separation into these two fractions will be the most viable solution to ensure a simple and clear system for everyone, most importantly because of the many small households in Copenhagen . Also, it must be taken into consideration that collection costs in the old residential blocks be kept at a realistic level . In Copenhagen, the largest recyclable fraction is food waste and this fraction amounts to about 20% of household waste . As mentioned above, this waste is the second largest source of chloride pollution in the waste . In addition, the food waste has a relatively poor value as energy source at the waste-to-energy plants due to its poor combustion value . Lastly, it is possible to obtain a high-quality recycling product through correct collection and treatment, which may be used as manure or fertilizer . The energy can be used through the production of biogas . A precondition for this solution is that the material fraction can be kept absolutely clean . If not, there will soon arise problems with the content of heavy metals . Therefore, it has been decided in Copenhagen to operate with a "wet" fraction containing nothing but food waste . A scheme, carried out in conjunction with R98, has been set up on a preliminary basis in two test areas in the neighbourhoods of Amagerbro and Vesterbro with a total of 2300 households . In 1988, 40 .6 t of food waste was collected from the area, corresponding to a collection efficiency of about 45% of the calculated potential at 50 k person - ' y - ' . The neighbourhoods consist of residential blocks with or without chutes . Results show that it is possible to produce a genuine high-quality compost . For instance, the heavy metal content is as low as 41 ppm for lead, 0 .38 ppm for cadmium, 0 .19 ppm for mercury, and 1 .0 ppm for arsenic, which is clearly less than the most strict Danish limits . The greatest problems have arisen in relation to the collection, engendered by difficulties in developing a sufficiently solid compostable paper bag . R98 has opted for tests with a biologically decomposing plastic bag . As to the treatment, the waste has until now been treated in a compost plant with R98 . The plant has now been shut down because of operation problems, and R98 is now doing the composting at a plant outside of the municipal borders . A committee was established in 1989 which before deciding to build a full scale composting plant will evaluate whether a biogas compost plant should be established instead . It is considered reasonable to be able to produce not only quality compost, but also to utilize the energy content of the waste . During gasification, a



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considerable energy recovery can be obtained . The recovered energy will be even somewhat higher than if the waste were incinerated in a waste-to-energy plant . The committee concluded its deliberation later in 1989 . As a result of the conclusions in the report a company was formed of Miljokontrollen, R98, Amagerforbrxnding and the city lighting department . The company issues an invitation for tender in the EEC to explain the possibilities of building a plant . The result of the tender is presented to the city council . It is assumed that collection of food waste will be fully expanded throughout the municipality in 1993, so that a clean, recyclable fraction and a "sundry" fraction respectively will be collected . The collection of organic waste also includes the separate collection of garden waste from the single-house neighbourhoods in the municipality . This scheme was established in 1988, and about 7000 t are being collected per year . The waste is collected from the address once every month . From other districts in the city, garden waste can be delivered at the recycle stations described below . R98 is in charge of this scheme, and for the treatment of this waste the company has built a low technology compost plant in connection with the sewage treatment plant at Damhussâen . The idea has not been to combine the organic waste from the two schemes . Firstly, because garden waste can be treated with the use of low technology, and secondly because the heavy metal content in this waste fraction is probably higher, due to massive lead pollution from traffic . In the neighbourhood other major waste fractions are being collected for recycling . Today, these schemes comprise the collection of bottles and glass, and newspapers and magazines, by R98 via special containers placed in the city . Most important is the glass collection . The collection of glass has high priority, as this is a non-combustible fraction which contributes to the reduction of the waste's combustion value and remains intact in the clinker . In 1990, 2700 t of bottles and glass were collected from 260 containers . The scheme is continually being expanded . A taxation on packages has been passed in Denmark . As a consequence, new bottles are now being washed and recycled, while broken or unsaleable bottles are being remelted . Newspapers and magazines are being collected because of the large quantity of this fraction . Collection is obligatory by law from 1 January, 1990 . In 1990 13,000 t of paper from about 8000 containers were collected, corresponding to about 60% of the potential . The scheme was introduced in 1984, and it is still being expanded . Presently, there are ongoing experiments with various collection schemes in residential neighbourhoods, one method being collection at the pavement, another one being the setting up of containers at convenient locations . The material is screened at R98, and after that sent to Genfiber A/S in Asserts on Funen for deinking . After reconstruction of the company in 1987, R98 today owns part of the company in order to secure sales of the material collected . This security was increased in 1990 when R98 in cooperation with private partners formed the company Danfiler A/S that deals with the trade of de-inked and de-fibrated materials . In the district all other material fractions are being collected, which with regard to recycling, better incineration or otherwise are collected separately . The district scheme is based on the establishment of seven to 10 recycle stations, throughout the municipality . The concept for these stations entails an opportunity to deliver the following fractions : • For recycling : bottles and glass cardboard newspapers and magazines sundry paper



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garden waste iron and metal textiles PE-plastic bricks and débris • For incineration : sundry combustible waste • For deposits : soil mattresses, etc . PVC and other hazardous plastic materials When the waste system has been fully expanded, bricks and débris, and most likely PVC too, may be recycled . The stations are laid out for the use of private and small enterprises, and there are no charges for the use . The first station was set up at Amager in cooperation with Amagerforbrxnding in April 1989 . During the first 3 months, 192 t were received at the station . Twenty one per cent was recyclable materials, 48% for deposits at inert landfills, 6% for deposits at sanitary landfills, and 26% for incineration . There are serious problems in connection with the localization of the stations in the densely built municipality . Establishing the next recycle station in the northeast region of the city was thus postponed several times, but finally established in June 1991 in cooperation with Vestforbrxnding . Once the recycle stations have been established throughout the municipality, Amagerforbrxnding will operate the stations placed within its catchment area, while R98 will operate those belonging to Vestforbrxnding . Not until 1989, when the instruction on waste management was passed, has this waste become an integral element of public waste regulations . A regulation on commercial and industrial waste was passed in 1991 . The main principles for-the present regulation are the separation of collection into pick up schemes and take-away schemes. Pick-up schemes imply that a concessioned carrier will pick up the waste at the address . Take-away schemes impose on producers to deliver the sorted-out fractions in question at a specified waste plant . Carriers must be authorized for transport of the sorted-out waste fractions . The principle behind concession and authorization regulation is to ensure high collection percentage, and high product quality . With the waste producer, public inspection will be simplified, as control with the sorting may be limited to controlling the enterprise's receipts from authorized carriers . The authorized and concessioned carriers, respectively, would in turn be obliged to hand in lists of received volumes from each producer . Carriers may of course lose their authorization or concession in case of breach of contract concerning regulations on sorting or delivery . Pick-up schemes will first of all be implemented for waste fractions, where the highest possible collection efficiency is considered crucial for the overall waste planning, or where there exist specific conditions for collection, due to, for example, the characteristics of waste . As with households, the organic waste was high priority . In 1988 a collection scheme was set up in cooperation with R98 for food waste from canteens and restaurants . Institutions and other kitchens with more than 100 k of food waste per week must now sort out the food waste for a separate collection scheme . The food waste is carried by R98 to the slaughter house waste treatment plant KAMBAS near Ringsted, where it is recovered as pig fodder . One hundred and thirty kitchens are now affiliated with this scheme, and about 2000 t are being collected annually . The 5 .3 .2 .2 Commercial waste .



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scheme is a high loss concern, but efforts are being made to reduce the deficit . A regulation on the scheme was passed in 1991 . As to other organic waste fractions, a major survey is being undertaken to clarify the volumes and the largest individual fractions . The survey is scheduled to be concluded later this year . Garden and park waste will be brought to the existing composting plant at Damhussoen, and organic wastes from households and commercial waste should be brought to the planned compost or or biogas plant, referring to the discussion above in section 5 .3 .2 .1 . The above-mentioned collection schemes for hazardous waste will similarly be carried out through pick-up schemes . For other recyclable materials regulation is imposed on businesses to sort out the fractions and deliver them separately at an assigned waste plant ("take-away" scheme) . This includes paper, cardboard, plastic, metal, rubber, wood, etc . Presently, surveys are being made to assess minimum volumes of each fraction for a producer to be obliged to participate in the schemes . As regards paper and cardboard, the collection schemes for commercial activities have been obligatory since 1990, following regulations from the Environment Protection Agency . Today, R98 is collecting paper, cardboard and plastic for recycling . At R98's recycle plant, G98, a sorting line, bale press and other facilities have been installed to treat the collected materials . R98 is also collecting confidential papers . In 1990, R98 collected about 36,000 tons of materials for recycling . The establishment and administration of an efficient and flexible collection system 21,000 t from households and 15,000 t from enterprises presupposes the establishment of efficient registration systems with the environment authorities . This should be done partly to select companies who can sort out individual fractions, partly to facilitate inspection and adherence . With support from the Danish Ministry for the Environment, and assistance from the Danish Technical University, Miljekontrollen is therefore in the process of developing a support system for classification, registration and decisionmaking for commercial waste . This is done to ensure a coherent terminology, and to develop a registration system that provides a workable management system for the waste plants' staff and for the inspection staff of Miljekontrollen (Fig . 6) . The first stage of this project was concluded in the summer of 1989, and it contains a registration system at four levels . (1) Total waste volumes . (2) Classification of the waste into four classes : hazardous waste, organic waste, sundry combustible waste, and sundry non-combustible waste . (3) Sub-classification of each fraction into about 30-40 sub-fractions . (4) Particular non-classifiable fractions, being registered under current initiatives . The three first levels are constant, while level number 4 may vary and can be changed continuously (Olson & Larson, 1989) . 5 .3 .2 .3 Demolition waste . Copenhagen municipality has rapidly increasing volumes of demolition waste . Renovation and reconstruction in elderly neighbourhoods of the city engender very considerable volumes of demolition waste . Presently, this waste amounts to about 450,000 t y - ', or as much as all other household and commercial waste in total . Obviously, this causes immense problems at a time of limited landfill capacity . A number of private crushing plants have therefore appeared in the municipality in recent years . Despite this it remains certain that the solution of these problems depends on a major,



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Total waste volumes

Organic

Hazardous

Sundry combustible

Classification of the Sundry waste into four non-combustible classes . Sub-classification of each fraction into about 30-40 subf ractions . Particular non-classifiable fractions, being registered under current initiatives .

Fig . 6 . Registration system.

comprehensive effort . In recent years, a number of tests have been carried out with sorted débris, with an aim towards enhancing the quality of possible recycle products, and likewise there have been experiments with use of various crushed products . R98 together with private partners in 1991 formed a major joint corporation to set up crushing and recycling facilities in Copenhagen municipality . The plant will be placed immediately at the highway on the west side of Amager . The erection of a crushing plant will be followed by regulations on sorting débris, and a utilization duty for the future crushing plant .

5 .3 .3 Sorting into combustible/non-combustible waste After the implementation of the above-mentioned schemes, there will still be very large volumes of waste for incineration or deposits . As mentioned, enhancing the efficiency of the classification into combustible and non-combustible waste forms an essential component of the waste plan . The waste-to-energy plants have in recent years altered their tax structures so that it is now much more expensive to deliver mixed, unsorted waste, as compared with sorted waste for incineration . In 1985 Vestforbrxnding enacted a tax differentiation for commercial waste, which determined that "green" sorted waste may be delivered at 160 kroner t - ' (U .S . $23), while "black" unsorted waste costs 300 kroner t - ' (U .S . $45) to dispose of . The differentiated price structure has meant that 75% of the commercial waste (90,000 t) is today being delivered as "green" waste . Vestforbrxnding is considering a total stop for deliveries of "black" waste, and introducing a fee of 1000 kroner (U .S . $82) for loads that turn out to be incorrectly sorted . In 1988, Amagerforbrxnding introduced a similar differentiation, but here this still concerns only large units that may bring the plant's leading-in shaft to a stop, thus causing operation stops . In 1991 the tax structure of the two corporations was made identical .



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Vestforbrwnding and Amagerforbrxnding have, in 1985 and 1988 respectively, taken pre-sorting plants into use, to ensure the sorting of mixed loads . In addition, the plants may sort out large, pure recyclable materials . On a long-term basis, the most important tasks of the pre-sorting plants will be to enact control with the observation of implemented sorting regulations . As a consequence of the new principles for delivering waste at the waste-to-energy plants and the landfills, a number of reloading stations have arisen, where unsorted commercial waste is being reloaded before being carried to the waste-to-energy plants . Secondly, the aim of the reloading stations is to sort out pure waste that still may be delivered at inert landfills at considerably lower fees and without quota limits . One station has been established at R98, and likewise seven private reloading stations have appeared in the municipality . The sorting into combustible/non-combustible waste is enhanced through regulations imposed on individual enterprises to sort their residual waste into those two types, at the very source . For small waste producers there are admitted an opportunity to deliver their waste altogether with an aim towards sorting it at a reloading station, or possibly at the pre-sorting plants at the waste-to-energy plants . The very small enterprises may also deliver their waste unsorted at the recycle stations set up in the districts . References Olsen, K . & Larsen, I . (1989), Furthering cleaner technology-the role of the decentral authorities . In Proceedings of the ISWA-conference- Waste Minimization and Clean Technology : Moving Towards the 21st Century, Geneva . Bibliography Larsen, I . (1990) . Waste minimization and recycling in Denmark . Paper presented at the ISWA 1990 Annual Conference Waste Management in Europe 1992, Amsterdam, September 11-13, 1990 .

Larsen, I . (1990) . Organic wastes . A resource or an environmental problem? A view of the European scene . Paper presented at the IULA congress, The World Congress for a Sustainable Future, New York, Sept . Copenhagen : M . Ljr konhollen . Larsen, I . (1990) . Environmental planning in the Nordic countries . Paper presented at the NIM conference, Stockholm, June 6-8 . Copenhagen : Miljekontrollen . Energy and Environment in Copenhagen . Copenhagen : Department of Urban Planning and the 5th Department, the Lord Mayor's Office .