SEAWATER DESALINATION BY REVERSE OSMOSIS IN CHIGASAKI LABORATORY.

For the purpose of constructing a reverse osmosis (RO) sea water desalination plant of 800 m**3/day capacity, a series of tests on the following themes have been carried out: performance and durability of 8B modules made in Japan; simplification of pretreatment system; establishment of energy recovery system. Domestic modules showed good and stable performance during long term operation, and the water recovery ratio of these modules has been raised to 40%. In-line coagulation and filtration systems have been established for pretreatment, instead of coagulation, sedimentation and filtration system. The energy recovery equipment consists of a high-pressure pump, motor and hydraulic turbine on a common base. Experimental data show that about 20% of required power for the pump was recovered.