Giving Old Anaerobic Digesters a New Look

The City of Clearwater, Florida maintains and operates three wastewater treatment plants. The East Advanced Pollution Control Facility (APCF), with a capacity of 5.0 mgd, the Northeast APCF with a capacity of 13.5 mgd, and the Marshall Street APCF with a capacity of 10.0 mgd.The Northeast APCF and Marshall APCF use anaerobic digesters to stabilize biosolids.. The East APCF does not include solids-handling facilities. The biosolids from the East APCF are hauled and processed at Northeast APCF.During the late 90's/early 2000's the city experienced poor results from their digesters, due to deteriorated heating and mixing equipment. Consequently the City embarked on an initiative to invest in a rehabilitation program for all their digester facilities.The purpose of this paper is to provide data on increased gas production and reduced hauling cost savings after the primary digesters were rehabilitated in late 2006.