Effects of Electrochemical Treatment on Microcystis Extinction

The effects of electrochemical treatment on Microcystis extinction were studied. The test water flowed within a space between electrodes separated in parallel. Two kinds of test water were used : deionized water and sterilized water of Lake Kasumigaura. Cultured Microcystis cells were suspended in the two kinds of water, and the growth rate and the extinction rate of the cells were evaluated after the treatment. The extinction rate of the cells suspended in the lake water was much higher than that of the cells suspended in the deionized water. With the lake water, the extinction rate reached 98% by applying 10 V between the electrodes, and within 5minuites of the treatment time. Although it was not detected before the treatment, more than 10mg·l-1 of free chlorine was detected from the lake water after the treatment. This implies that the free chlorine formed by the electrolysis of the water plays a key role. A good positive correlation between the extinction rate and the product of current density and the treatment time, seems to support the hypothesis.