Variation of biofilm formation on distribution pipe depending on water treatment processes and pipe materials

Biofilms may appear as a patchy mass in some pipe sections and may lead to deterioration of bacterial water quality, amplification of corrosion, and generation of bad tastes and odors. Characteristics of biofilm formation were studied depending on pipe materials, water treatment processes and temperature. From the results of this study, on the whole, HPC (heterotrophic plate count) increased with lapse of time and decreased according to decrease of temperature. The highest HPC showed on CIP (cast iron pipe) material for all treatment processes. The lowest HPC showed on CIPP (cured in place pipe) liner and SSP (stainless steel pipe) material. The high HPC showed in the pipe feeding tap water. The mean HPC of room temperature was higher than that of low temperature. The results of pilot test, the HPC of DCIP (ductile cast iron pipe) was higher than that of CIPP. The results of investigation on the field, we could see correlation between AOC concentration of tap water on the field and the HPC in tubercle. In the identification of species in biofilm, on the whole, Pseudomonas spp. dominated.