COLUMBUS BIOSOLIDS FLOW-THROUGH THERMOPHILIC TREATMENT (BFT3) AS A COST EFFECTIVE MEANS TO ACHIEVE CLASS A DIGESTION

Like many utilities across the country, the Columbus Water Works (CWW – Columbus, Georgia) has found access to previously available lands for Class B biosolids application becoming increasingly limited. In response to these concerns, CWW considered a number of processes to further reduce pathogens (PFRPs) and operational options for achieving Class A biosolids quality allowed in the 40 CFR, Part 503 regulation1. A new, potential Class A process was identified to be very cost effective for retrofit to a treatment plant with existing anaerobic digesters. Development of a new Class A process (PFRP equivalent process) would require considerable research effort and negotiation with the Pathogen Equivalency Committee (PEC) of the United States Environmental Protection Agency (USEPA); this was determined to be worth the investment based on the potential capital and operational savings that would result from nation-wide application of the new technology. The treatment technology has been named “Biosolids Flow-Through Thermophilic Treatment” (BFT3). This paper provides an overview of the BFT3 process, discussion on CWW's approach to developing the process, and preliminary pathogen testing data from the investigation.