ABSTRACT

This chapter takes the reader from single and two stage systems to the multistage systems required to effectively model a complete composting process. Composting is a process of organic decomposition that begins with substrates rich in biodegradable volatile solids and proceeds gradually and continually to a stable product with greatly reduced BVS content. There are no sharp boundaries or discontinuities between high-rate and curing phases. The two must be viewed together as part of a complete, multistage system. Systems were developed with one stage and then two stages arranged in series. The chapter presents the building process by first considering a reactor system for composting of sludge cake. Operators at sludge composting facilities may be reluctant to add water back to the process, particularly when one of their duties is to remove as much water from the sludge as possible during dewatering.