Drinking Water Quality Measured in Laboratory Scale Water Tanks

Abstract

Water tank building materials including wood from Chamaecyparis nootkatenisis and Cryptomeria japonica, fiber reinforced plastics and stainless steel (SUS316) were measured for water quality using laboratory scale water tanks. For the fiber reinforced plastic (FRP) and stainless steel tank, all tested water quality parameters (pH, suspended solids, color, nitrites, nitrates, residual chlorine, trihalomethanes, coliforms, Escherichia coli, standard plate count and heterotrophic bacteria) satisfied drinking water quality criteria in Japan. The chlorine reduction rate in the wood tanks correlated with the surface area of the tank, that is, water interface divided by the stored water volume. Half-life of residual chlorine in the full scale wood tank is calculated at approximately 4 days, based on the results of the chlorine reduction rate in the laboratory scale wood tanks. The results indicate that water from the full scale wood tank may satisfy drinking water quality criteria in Japan.