浄水処理工程におけるハロ酢酸類の生成実態と対応策に関する研究

抄録

The formation potentials of haloacetic acids (HAAs) in raw water and the behavior of HAAs in process waters and finished water were investigated during the high turbidity of raw water associated with typhoons and heavy rains and normal turbidity conditions. During the high turbidity conditions, the HAA formation potentials increased with an increase in total organic carbon. In case of high turbidity levels of raw water, the concentrations of HAAs, particularly dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), in process water and finished water were higher due to prechlorination. The decrease of removal rate of the DCAA formation potentials in the coagulation and sedimentation processes by prechlorination was greater than those of TCAA. For both substances, the removal rates of their formation potentials were lower for the longer prechlorination time, and the percentage of reduction was about the same level. In the high turbidity levels of raw water, the removal rate of the HAA formation potentials by the coagulation and sedimentation processes was high, but the formation potentials after prechlorination significantly increased from normal turbidity levels.