Minimizing the flow of the membrane unit concentrate
in the process of surface runoff and drain water treatment and reuse

Summary

Possible treatment of surface runoff and drain water collected from the territory of an industrial enterprise using the method of reverse osmosis and nanofiltration is studied. Reuse of effluents provides for eliminating the payment for the environmental damage resulting from discharges into surface water bodies. The studies on determining the possible use of a membrane nanofiltration system for surface runoff and drain water treatment and reuse in preparing feedwater for water-heating boilers are described. An important characteristic of the technology is the minimum acceptable flow of membrane unit concentrate discharged into the sewer. The results of experiments are presented that provide for determining the intensity of calcium carbonate crystallization in the channels of membrane units, as well as the results of studying with a scanning electron microscope the formation of crystals in the concentrate flow.

Key words

reverse osmosis , nanofiltration , scaling on membranes , surface runoff and drain water of industrial sites , water treatment schemes with membrane use , reducing concentrate flow in reverse osmosis units

Ways of reducing the operating costs of membrane units
for the preparation of drinking water from underground water sources

Summary

Experimental investigations have been conducted to determine the main process parameters of membrane units (filtrate yield, the rate of scaling on membrane surface). Basing on the results of the experimental studies the total costs of purification of underground water of various chemical composition were obtained. The studies were conducted on laboratory benches with the use of nanofiltration membranes with various selectivity rates. The consumption of service chemicals and operational costs for the equipment were calculated by the software designed earlier by the authors for determining the process parameters of membrane units. While designing membrane units, nanofiltration membranes with low values of selectivity, power consumption and expenditures for chemicals are preferred. The dependencies of the calcium carbonate scaling rates on membrane types and the multiplicity of volumetric concentration of source water were obtained. A comparison of costs shows that the use of membranes even for cases of water deferrization is more economical than the known traditional technologies.

Key words

calcium carbonate , ground water , concentrate , reverse osmosis , nanofiltration , water softening , scaling on membranes , deposits of slow-soluble salts in water , scaling inhibitors , scaling rate