Abstract
Coagulation treatment is one of countermeasures for turbid water in a reservoir that is brought by lowering of surface level or sediment transport in a reservoir. We have taken volcanic ash coagulants which contain allophane and investigated their coagulation, dispersion characteristics and electrokinetic phenomena. Moreover, we conducted site experiment of coagulation treatment by using volcanic ash coagulants. Through this study, coagulation was observed when pH of suspension was adjusted to 7 to 9. Zeta potential of coagulants were raised by adding ultrasonic dispersion. High coagulation performance was obtained in site experiment, on the other hand, reduction of coagulants and effective dispersion method were desired for the practical use of volcanic ash coagulants.
