LAUSR

Abstract This study investigated the effects of pipe materials on biofilm growth in full-scale recycled water (RW) distribution system. A biofilm reactor containing high-density polyethylene (HDPE) and polyvinyl chloride (PVC) pipe coupons was fed directly with chlorinated water from the storage reservoir of a full-scale RW distribution system. The reactor was operated at a variable water flow rate of 0.08−0.30 L/min and free chlorine residuals of 0.05−0.7 mg/L. Total carbohydrate, biofilm thickness, biofilm mass, and extracellular polymeric substance (EPS) measurements showed that both HDPE and PVC pipe surface materials are susceptible to biofilm formation and there was no significant difference in biofilm formation between the two pipe materials used in this study. The difference between total chlorine and free chlorine was significant even in the presence of minimal ammonia-nitrogen (