The Importance of Waste Characteristics and Processing in the Production of Quality Compost

The quality of compost produced from municipal solid waste or selected waste components therefrom is determined primarily by the characteristics of the waste components and by the processing methods. Consequently, a knowledge of the characteristics of the waste components and of the fundamentals of preprocessing and composting technologies is required in order to design a system to produce a compost to a desired set of specifications. The specifications can be a result of regulations, or market conditions, or both. The characteristics of the waste to be composted can be manipulated at the point of collection (e.g., by separate collection of the predominantly biodegradable waste components) and during subsequent processing. This paper focuses on the characteristics of various waste components and of mixtures thereof, the key fundamentals of processing relevant to composting, and the influence of waste characteristics on compost quality. Besides the discussion of applicable fundamentals, the characteristics of compost produced from mixed solid waste organics and from mixtures of source separated components are compared both on a theoretical basis and related to some actual data. The discussion provides information relevant to the determination of the advantages and disadvantages of using mixed solid waste organics or source separated wastes as compost feedstocks.