The purpose of this survey is to explore ways of reclaiming wastewater to produce high-quality low-cost water for recreational reuse by using a reverse osmosis membrane in advanced wastewater treatment. We examined membrane modules that were able to be used for wastewater treatment in fiscal year 1988.
The parameters used to evaluate the membrane were the permeate quantity, permeate water quality, flux decline coefficient, and recovery rate of the permeate quantity by chemical cleaning. As a result, spiral-wound polyvinyl alcohol composite membrane and hollow-fiber cellulose triacetate reverse osmosis membrane were found to be of high practical value. The permeate through these membranes was colorless, transparent, and odorless, with an appearance equivalent to city water. The rejection rate of the fecal coliform group was 100% and the COD of the permeate was 1-2 mg/l, with a chromaticity of 1 degree or less and a phosphorus content of 0.01 mg/l. Under the same pressure condition, these membranes provided three times more permeate quantity than a conventional acetyl cellulose membrane having a time-proven performance. Moreover, these membranes were sufficiently resistant to fouling that they can recover to a 100% permeate quantity by chemical cleaning when they were fouled.
In-depth analyses of organic matters in a full-scale seawater desalination plant and an autopsy of reverse osmosis membrane
