01-03-1985 Council Packet Special Meeting

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Waste combustion technologies have been commercially available for some time now. The mass -burn and RDF technologies, in particular, are increasingly being used in this country. The mass -burn technology has over 30 years of advance- ment, mainly in Europe. Although newer, the RDF technology is receiving greater attention because of its flexibility and potentially lower costs. Therefore, technological factors should not impede the development of combus- tion facilities in the Metropolitan Area. Economic and public risk considerations have been the major reasons for the slow development of combustion facilities in the region. Only one small-scale facility, in Savage is currently in operation. Proposed large-scale projects have never been able to compete with the region's low-cost land disposal sys- tem. Such projects have always required large capital investments and long- term public commitments of waste supplies. Finally, there were always linger- ing questions whether better alternatives were available. However, alternative Froposals have never proven capable of handling the large quantities of waste that combustion facilities can. Priorities Waste combustion must play a key role in the region"s future waste management system. It could recover as much as 50 percent of the total solid waste gener- ated annually. Priority must go to developing a system of major combustion facilities that will be operational by 1990. Large-scale facilities need to be built each capable of handling as much as 500 or more tons per day of mixed municipal waste. In general, large-scale facilities provide the potential for greater control of air emissions because they have higher combustion efficien- cies. These facilities will not be competitive in the short-term; therefore, they will require assurances of an adequate waste supply. The RDF technology is more adaptable to the regional strategy because of its flexibility. CENTRALIZED COMPOSTING AND CO -COMPOSTING Alternatives Another form of centralized resource recovery is composting or co -composting of mixed solid wastes with materials high in nitrogen. Similar to backyard com- posting of yard waste, large composting facilities rely on the biological pro- cesses of microorganisms to break down the organic fraction of processed municipal solid wastes. Composting facilities process the waste, using shred- ding and mechanical separation techniques similar to energy recovery facili- ties. The viability of composting plants depends on the markets for the final product. Centralized composting facility technologies include open "windrow" systems (that is, piles of organic refuse that are turned using large road machinery) and enclosed systems where the oxygen and temperature levels are controlled. These types of resource recovery systems are more common in Europe than in the United States. Centralized composting is, however, increasingly being used in this country. Until recently, the co -compost technology has received little attention in the region. Recent research by the Council indicates that the technology offers a number of opportunities, and that it should be a part of the regional strategy. Co -composting technology is readily available and applicable to the region. The technology includes use of windrows and enclosed vessels. Both methods have been successfully used for years particularly in Europe. 75