Sludge removed by primary sedimentation is stabilized by anaerobic digestion
in anaerobic digestion tanks which are a part of the primary treatment
facilities. Waste sludge from the carbonaceous and nitrification activated
sludge processes are also stabilized by anaerobic digestion. Methane gas
produced by the anaerobic digestion process is burned in five 500 KW methane
fueled engine generators to produce electricity. This system produces approximately
20 percent of the plant's electrical requirement.
Sludge Heat Drying Facility
Digested sludge from the anaerobic digestion process is dewatered by belt filter
presses or dried on sand drying beds. The belt press sludge is then dried to
produce a fertilizer product in a heat drying plant using a natural gas fired
rotary kiln. This biosolids product goes to distribution and marketing.
Biosolids that are not heat dried are applied to agriculture land as a soil