Reverse osmosis on secondary sewage effluent: The effect of recovery

Abstract In the treatment of chemically clarified secondary effluent by reverse osmosis, product quality, flux stability and flux regeneration were examined as a function of the recovery of the operation. As the recovery of the plant increased, the salinity of the product increased while the level of organic contamination in the product remained constant. The effect of recovery on the economics and productivity of reverse osmosis is examined quantitatively using the experimental results. Provided the precipitation of calcium sulphate can be prevented, it is economically desirable to maximise recovery; the upper limit of recovery will be determined by the salinity of the product which can be tolerated.