||Brown and Caldwell, Pleasant Hill, CA. ;E and A Environmental Consultants, Inc., Stoughton, MA.;Environmental Protection Agency, Cincinnati, OH. Water Engineering Research Lab.
Investigations at five full-scale municipal sludge composting facilities are described in the report. Study objectives were to assess design, construction, operation, and cost features of static pile and windrow technologies used at each facility and to compare these features for municipal sludge composting applications. Three static pile facilities, one conventional windrow facility, and one aerated windrow facility were investigated. One static pile facility composts anaerobically digested sludge, one composts limed raw sludge, and the third composts unlimed raw sludge. Both windrow facilities compost anaerobically digested sludge. Sludge loadings varied from 50 to 500 wet tons per day. Static pile and windrow technologies typically require 0.08 to 0.14 acres per wet ton per day. Paving and covering key operating areas can enhance reliability, but site-specific factors need to be assessed. Both technologies can produce a marketable product under variable operating conditions. Technology-specific findings related to static pile construction or windrow formation, process control, drying, screening, curing, and cost are described.