| Description |
The Salt Lake Valley Solid Waste Management Facility (SLVSWMF) in Salt Lake City, Utah, is considering changing how municipal solid waste (MSW) is managed. Specifically, the SLVSWMF is planning to shred all incoming MSW prior to landfilling. Landfilled solid waste at the SLVSWMF is mixed and typical of MSW in the United States, consisting of incompressible and compressible types of waste. Shredding MSW reduces void space and creates a more easily compacted mass. To test the density and rebound of shredded and nonshredded MSW, a 1 yd3 steel compactor was constructed, which has the ability to deliver a load of up to 11125 lb/ft2. Compaction pressure was designed to simulate the in-situ compaction typically achieved at the landfill by use of a mobile compactor. MSW was loaded into the compactor until filled, and incremental loads were applied until11125 lb/ft2 was reached and was measured using a pressure gauge. Shredded waste was generated using a waste shredder unit, which incorporates low speed, high-torque technology. The mass and volume of compacted waste were also recorded, which allowed for the determination of densities under applied pressure. The initial average in-place density was 297 lb/yd3for the nonshredded MSW and 592 lb/yd3 for the shredded MSW. The final average in-place density was determined to be 626 lb/yd3 for the nonshredded MSW and 1144 lb/yd3 for the shredded MSW, both of which were calculated after the maximum load had been applied, released, and left to rebound for 24 hours. Rebound of the nonshredded and shredded MSW was similar between the two with an average of 3.1 inches for the nonshredded MSW and 3 inches, respectively, for the shredded MSW. Overall this research indicates that compaction of shredded MSW creates a more structurally stable mass that is much denser than nonshredded MSW. The average final in-place density of shredded MSW is 65.1% greater than the average final in-place density of nonshredded MSW. The increase in final in-place density of shredded MSW translates directly into a volume savings of 39.4%. Should municipalities decide to shred solid waste, a significant amount of landfill volume will be conserved. |
