| 摘要 |
PURPOSE:To prevent the deterioration in the sensitivity of a pH sensor due to the sludge in water to be treated and to purify water under the accurate control of pH. CONSTITUTION:Water to be treated, a flocculant and a pH regulator are charged into a mixing tank 21, and the liq. mixture in the tank 21 is subjected to solid-liq. separation by a membrane separator 29. In this case, a pH sensor 31 is dipped in the permeated liq. of the separator 29 to measure the pH of the treated water separated by the membrane, and the amt. of the pH regulator to be added to the tank 21 is controlled based on the measured pH value. Since the pH of the permeated liq. free of the suspended foreign matter is measured, the deterioration in the sensitivity of the sensor 31 is prevented, and accurate measurements are made at all times. Besides, sludge capable of being excellently filtered is formed by the precise addition of the pH regulator, and the filtration efficiency in the membrane separator 29 is improved. |
