Municipal solid waste composting: Physical and biological processing

A wide range of technologies has been incorporated in the current generation of municipal solid waste (MSW) composting facilities. These include separation processes, size reduction and materials preparation, and biological processing control. Many of these technologies were originally developed for other purposes, and are being adapted for different functions with new feedstocks. Separation systems traditionally were designed to recover recyclable material, but are now also used to reduce inert and chemical contaminants. Size reduction can be coordinated with separation equipment to enhance materials recovery and contaminant reduction. Biological processing methods combine process control with materials handling to manage a complex microbial ecosystem. Linked with an MSW collection program, these technologies must act as a coordinated system to transform incoming waste materials to a marketable end product. This paper reviews the variety of processing systems available, with particular reference to innovations which can enhance the production of MSW compost.