Biodegradable Dissolved Organic Carbon in Trickling Filter and Activated Sludge Wastewater Treatment Plants

Abstract

The chemical composition of wastewater derived dissolved organic carbon (DOC) is complex and consists of moderate and high molecular weight organic compounds with different levels of biodegradability. Biodegradable DOC (BDOC) is a portion of DOC that can be mineralized by an acclimated mixed bacterial culture. DOC and BDOC data were collected along the treatment trains of two wastewater treatment plants (WWTPs) with a two-stage trickling filter (TF) system and an activated sludge (AS) + moving bed bioreactor (MBBR) system. Results showed that BDOC varied significantly within the treatment facility and between the two facilities.From primary clarifier to final effluent, the TF plant removed about 90% of BDOC, while the AS + MBBR plant removed about 80% of BDOC. Effluent BDOC to effluent DOC ratio(biodegradability) for the TF plant was73% while it was 63% for the AS + MBBR plant.