Detection of Biofilm Layers in Water Plumbings and Determination of its Effect on Water Quality

Abstract

Water quality deteriorations in the plumbing are mainly resulted from accumulations and biofilm layer formation on the pipe surfaces. Biofilms may cause significant health risks on human health due to its pathogen content. In this study, biofilm formation on the plumbing, the presence of pathogenic microorganisms in biofilms and their effects on water quality were examined by membrane filtration with dehydrated medium (NPS) method in 22 different buildings in a facility’s water network. A relation with biofilm formation and water quality deterioration with the age of the plumbing and the pipe material was also studied. The results were expressed as colony forming units (CFU). According to the results of the galvanized metal pipes, the average colony count was determined as >200 CFU/250 mL, average pathogen count was calculated as 107 CFU/250 mL and the highest deterioration in the water quality were observed. For the PE (Polyethylene) pipes, the average colony count was found as >200 CFU/250 mL and the average pathogen count was found as 145 CFU/250 mL. No physical and chemical changes in water quality were observed. For the PPRC (Polypropylene Random Copolymer) pipes, neither physical/chemical change in water quality nor pathogenic growth were observed. The total colony count was found as 34 CFU/250 mL. Biofilm formation was detected at 15 points in the network. Pseudomonas aeruginosa was the most common detected pathogens in plumbing as 12 points from 22 buildings. The highest colony formation was Escherichia coli, which was detected in four of 22 plumbing as 600 CFU/250 mL colonies. It has been observed that more accumulations occurred in galvanized metal pipe surfaces, and microbiological growth was higher than PE and PPRC pipes.