Agenda - Council - 04/23/1985 - Laserfiche WebLink

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m ,! Materials recovery at centralized facilities has good possibilities in the Metropolitan Area, particularly if the technology is used with other processing methods. As previously mentioned, similar equipment can be used to accomplish a number of purposes. Centralized materials recovery can also serve as a backup if source-separation approaches do not meet anticipated objectives. 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. 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 munic- ipal solid wastes. Composting facilities process the waste, using shredding and mechanical separation techniques similar to energy recovery facilities. The viability of composting plants depends on the markets for the final prod- uct. 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. Indications are that a number of markets exist in the region to use co-compost products. Some question remains, however, regarding the competitiveness of the product with similar products currently being used. The University of Minne- sota, in cooperation with the Council, has begun a research and development pro- ject to determine the marketability of co-compost in the Metropolitan Area. The net effect of including co-co, posting in the regional strategy is to increase flexibility and lessen even further the amount of residuals requiring land disposal. The question about the marketability of compost should not by itself discount co-composting as an important part of the region's future waste management system. However, public subsidies may be required until a long-term market demand is developed. LAND DISPOSAL As a method of waste management, land disposal is a last resort. Waste reduc- tion and resource recovery are preferable methods, but even with land disposal there are factors to consider to minimize environmental and land use problems. Waste reduction and resource recovery are estimated to reduce significantly the need for land disposal but will not eliminate it entirely. Landfills for munic- ipal solid waste will be necessary on a short-term basis while reduction and recovery systems are developing. They will also be necessary for the residue from recovery operations. However, their use should be kept to an absolute minimum.