Assessment of drinking water filter microbial communities using taxonomic and metabolic profiles

Biofiltration is used in drinking water treatment to oxidize the biodegrada ble fraction of natural organic matter (NOM), thus controlling disinfection byproducts (DBP), DBP formation and microbial regrowth. Most work to date has focused on assessing drinking water biofilter performance; the microbia l dynamics of biofilters have not been examined and are poorly understood. The objective of this research was to provide baseline information about th e impact of design, operational and water quality parameters on NOM and DBP precursor removal, and microbial biomass and community structure profiles of biologically active drinking water rapid media filters. Phospholipid fai ry acid (PLFA) profiles and the BIOLOG system for detecting the metabolism of sole carbon sources were found to be useful for characterizing the micro bial communities in drinking water biofilters. Substrate removal was impact ed most by ozonation, contact time, backwashing with water containing disin fectants, and low temperature. Using the PLFA technique, it was found that ozonation, contact time, and backwashing with water containing disinfectant s had the greatest impact on microbial community structure. The BIOLOG syst em differentiated communities based on ozonation, contact rime, pH, and tem perature. (C) 1999 Published by Elsevier Science Ltd on behalf of the IAWQ. All rights reserved.