Reverse-osmosis concentration from environmental water

Industrial Wastes. Closely related to seawater concentration is the simultaneous concentration of industrial effluents and recycle of recovered water (see Wastes, industrial). These appHcations are expected to increase as environmental restrictions increase. Examples are the concentration of blowdown from cooling towers in power plants concentration of reverse osmosis blowdown and the processing of metal treatment wastes (11) (see... 

T HE SEPARATION, CONCENTRATION, AND FRACTIONATION of organic solutes in aqueous solutions by reverse osmosis are of practical interest from the points of view of water purification and collection of samples for environmental analysis. Although many experimental data on the separation of organic solutes are available in the literature (1-2), very few fundamental works have been accomplished so far. We have been studying this subject in the framework of the preferential sorp-... 

In biotechnology, the products concerned are removed from aqueous solution by extraction with methylacetate, butylacetate, isobutyl methyl ketone etc. The remaining aqueous substrate is saturated with the extraction solvents. Sometimes this causes problems with regard to environmental regulations. Table V shows that the solvents can be remored almost entirely by reverse osmosis. The concentrate consists of two phases, namely, the solvent saturated with water and the water saturated with solvent. These can be separated by means of a settler. The water phase is recirculated to the reverse osmosis. The saturated solubility in Water at room temperature is 19 OOO mg/litre for isobutyl methyl ketone, 3300 mg/litre for butyl acetate and 9 500 mg/litre for methyl acetate. As the results in table V show, the retention for isobutyl-methyl ketone increases with increasing concentration. This result is remarkable, as generally a decrease in retention is observed with increasing concentration. 

The focus of a US EPA (Environmental Protection Agency) sponsored project was to separate anionic and cationic dyes from process water and chemicals by reverse osmosis and to re-use the concentrated dyes for coloration of automotive fabrics, with addition of some fresh dye if necessary (Brandon, 1980). It was not always possible, however, to generate sufficient recovered dye nor to completely adjust the desired shade. It was also difficult to match color shades when very dark concentrate was used. 

A polymer products operation in Arizona uses reverse osmosis to eliminate the discharge of cyanide-containing rinse water from one of the company s four plating units. The process, which concentrates the cyanide and separates it from the rinse water, reduces the environmental impact of the discharge and conserves valuable plating materials and water treatment chemicals. 

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