Evaluation of Composting of Municipal Solid Waste

Millions of tons of organic waste are lost each year by being deposited in landfills instead of being composted. Composting would increase the life of landfills and reduce the loss of renewable resources. Current composting techniques take approximately 6 months to break down the organic components, such as yard trimmings and food waste. In addition, a large amount of area is required for the windrows piles. Recycling techniques help to separate organics, such as yard trimmings and food waste, from the municipal solid waste (MSW) stream for composting. However, these techniques are time consuming, costly, and not extensively practiced. Since separation of the organic faction of MSW is not practical, it is important to seek ways to accelerate the breakdown of organics while composting the entire MSW stream. The Utah Water Research Laboratory was approached by Bio-Environmental Resource Recovery International (BERRI) to determine the impact of the Microbial Assisted Regeneration System (MARS) process. Various agricultural waste, MSW, construction and demolition waste, and organic contaminant mixtures were assessed to determine the quantity and quality of compost produced using the MARS process. A field-scale commercial compost study was conducted. Treated and control windrows were constructed to compare the MARS inoculum by quantity and quality of compost produced, organic stabilization time, and individual component sorting (i.e., green waste, wood, agriculture waste, food waste, MSW, C&D debris, and tires). Specific volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs), as well as a common pesticide, carbaryl, were added specifically for this study and the compounds were analyzed for degradation rates. The quality of the compost product was assessed using a method developed for classifying municipal solid waste compost. The quantity of compost produced was determined by screening the entire volumes of each pile to determine a gross production of compost for each pile. Compost samples were analyzed for VOCs, SVOCs, and carbaryl. The quality of compost was found to have a very low nutrient capacity making the compost only useable as a soil conditioner. Treated piles showed a significantly larger amount of compost production and a decreased time for organic stabilization. No significant degradation of plastics or woods components was observed in any of the treatments used in the study