PURPOSE: To prevent the occurrence of blinding due to the growth of microorganisms in apparatus economically and effectively by admixture of sodium hypochlorite produced by electrolysis of the sea water into the original sea water followed by treatment using a reverse osmosis apparatus.
CONSTITUTION: The sea water SW is pumped up to the storage tank 1 by the pump P1, then regulated its pH to approx. 6, then sent to the tank 3 for pretreatment, and then sent by pressure to the first reverse osmosis apparatus 4 by means of the high-pressure pump P2. The desalined sea water obtained at the apparatus 4 is sent to the second reverse osmosis apparatus 5 by the high-pressure pump P3 and then the high purity desaline water PW thus obtained is taken out in the arrow A direction. On the other hand, the concentrated sea water C obtained at the first reverse osmosis apparatus 5 is regulated its pH partly to less than 6 by the addition of hydrochloric acid from the tank 8 and then introduced into the electrolytic bath 6 where it is electrolyzed to generate sodium hypochlorite which is in turn added to the original sea water so as to regulate the concentration of sodium hypochlorite present in the mixed sea water to 0.05 ppm.
TSUGE HIDEO
SATOU HIROSHI
