Agenda - Council - 08/26/1980 - Laserfiche WebLink

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-ll- BIOLOGICAL TREATMENT AND RECOVERY What are the operational difficulties i_~n ~mplementing .biological treatment and recovery systems? Will there be adequate markets ~or compost product to make this an effective strategy? There are several types of resource-recovery systems that use the biological processes carried out by micro-organisms naturally found in municipal waste to treat and process the organic portion of the mixed-waste stream. There are two basic types of biological processing techniques: aerobi'c treatment, which takes place in an oxygen-rich environment, and anaerobic treatment, which takes place in an oxygen-free environment. Existing systems for aerobic treatment and recovery of solid waste include two types of composting methods: "open windrowing," where oxygen is kept in the material by frequent turning of composting material; and enclosed chambers using forced aeration. The material produced after treatment is an organic compost that can be sold a's a soil amendment. Preliminary surveys indicate that adequate markets exist in the Region. However, the quality of the compost product will determine the flexibility of its final use. Composting is an age-old system of recycling organic material. The problem is separating the inorganic metals, glass, plastics and other materials that will not break down from the organic material. If source separation or post-treatment mechanical screening techniques can be successfully employed, composting may be a cost-effective means of recovery. Composting has the advantages of requiring no outside fuel and leaving no unusuable residue. There are two experimental anaerobic processing systems: methane gas recovery and clay digesters. Both systems use the landfill in the treatment process. Landfill methane recovery requires impermeable barriers to trap gas and extraction pumps. The energy value of the waste is partially recovered in such a process unless shredding is employed prior to landfilling or the humus product extracted after processing. However, methane gas recovery is not considered a disposal abatement strategy. Clay digesters require shredding of ail the solid waste, which is then placed in a clay-lined cell. A clay cap is placed on the waste to prevent oxygen from entering the cell. Pumps are used to extract methane from the waste material. After ten years of methane recov- ery, the material in the cell could be dug out, aerated and then sold as a humus. The cells could then be reused, and would provide an abatement strategy for additional land disposal.