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

Abstract

Biofiltration is used in drinking water treatment to oxidize the biodegradable 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 microbial dynamics of biofilters have not been examined and are poorly understood. The objective of this research was to provide baseline information about the 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 fatty acid (PLFA) profiles and the BIOLOG system for detecting the metabolism of sole carbon sources were found to be useful for characterizing the microbial communities in drinking water biofilters. Substrate removal was impacted most by ozonation, contact time, backwashing with water containing disinfectants, and low temperature. Using the PLFA technique, it was found that ozonation, contact time, and backwashing with water containing disinfectants had the greatest impact on microbial community structure. The BIOLOG system differentiated communities based on ozonation, contact time, pH, and temperature.