LOW-TECHNOLOGY STORAGE AND AIR DRYING METHODS TO ACHIEVE CLASS A BIOSOLIDS

Class A or pathogen-free biosolids are being produced by low-cost, low-technology biosolids treatment processes. The low-technology processes evaluated here are: long-term lagooning, air drying, combined lagooning/air drying, and cake storage. This paper summarizes work completed for a Water Environment Research Foundation project on this topic. Prior research work provides considerable information about these proceses and their pathogen reduction capabilities. The specific operating conditions for these processes are crucial to achieving Class A biosolids material, and summary guidance is included in this paper on process operating conditions and guidelines for these low-technology processes.