Application of Ice Pigging in a Drinking Water Distribution System: Impacts on Pipes and Bulk Water Quality

Ice pigging is an emerging technique for pipe cleaning in drinking water distribution systems. However, substantial confusion and controversy exist on the potential impacts of ice pigging on bulk water quality. This study monitored the microstructural features and composition of sediments and microbial community structures in bulk water in eight multimaterial Chinese networks. Chloride concentration analysis demonstrated that separate cleaning of pipes with different materials in complex networks could mitigate the risk of losing ice pigs and degrading water quality. The microstructural and trace element characterization results showed that ice pigs would scarcely disturb the inner surfaces of long-used pipes. The bacterial richness and diversity of bulk water decreased significantly after ice pigging. Furthermore, correlations were established between pipe service age, temperature, and chloride and total iron concentrations, and the 15 most abundant taxa in bulk water, which could be used to guide practical ice pigging operations.