Abstract
In order to clarify the particles in the size range of 0.5-1 μm related to residual organic matter in the treated water of gappei-syori Johkasou, the influence of microparticles and bacteria in the treated water tank on the treated water quality was investigated. In addition, the changes of particles and bacteria in Johkasou were analyzed, together with the analysis for their relationships with the residual organic matter in the water of the treated water tank. A statistically significant correlation was found between the number of bacteria and BOD in the water of the treated water tank, indicating bacteria were the major component that contributed to the residual organic matter. The obtained results on the changes of the number concentrations of microparticles and bacteria along the treatment process of Johkasou indicated that most non-bacterial organic particles were removed in the tank of anaerobic filter bed and that most particles in the size range of 0.5-1 μm in the water of the treated water tank were consisted of bacteria. The cluster analysis further indicated that bacteria were the factor that most strongly related to the residual organic matter in the water of the contact filter bed tank and the treated water tank. These results suggested that reduction of bacteria number in the water of the treated water tank is necessary for reduction of residual organic matter in the treated water.
