Microbial Degradation of Complex Organic Compounds in a Danish Drinking Water Pipeline Distribution System

Abstract
Three specific compounds identified to leach from polyethylene (PE) pipes into drinking water were investigated for their microbial degradation in biofilm found in the Danish water distribution system. Two sample types were studied: field biofilm samples (collected in proximity to consumers), and polyethylene pipe biofilm extractions (collected close to the groundwater source), spiked with the target compounds. The three target compounds were quantified from the samples using 16s rRNA bacteria and archaea genes at standard concentrations of 15.3μl/ml and 50μg/ml, respectively. The degradation of these compounds was evaluated in polyethylene pipe biofilm extractions via inoculation under abiotic and biotic conditions, within a timeframe of the experiment (6-7 weeks), taking into account seasonal fluctuations. Statistical analysis demonstrated a significant difference in the biodegradation of drinking water between the two sites - taken in proximity to the consumer and the groundwater source, where the former produced higher activity. In conclusion, two out of three of the compounds studied would – if released from the pipes – reach consumers with only minor concentration decrease during water distribution.