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The growing interest in reverse osmosis includes not only coastal areas for desalinationof seawater but also inland areas where reverse osmosis is proposed for desalination of brackishgroundwater, particularly in arid climates where freshwater is extremely scarce. Most existingreverse osmosis facilities are in coastal areas, and the most common concentrate disposalmethods are discharge to surface water, discharge to a municipal sewer system, and deep wellinjection. In inland areas, these disposal options may not be available, and the remaining optionsmay be expensive and difficult to implement. Furthermore, in inland areas, the concentraterepresents not only a significant management problem, but also a waste of a precious resource,the water. This paper discussesSeveral issues in regard to concentrate in inland areas. First, theconcentrate must be isolated from the surrounding freshwater resources so that the existingresources are not contaminated. Evaporation ponds and deep wells (if suitable injection zonescan be identified) can be constructed to fit these criteria. The second issue, however, is torecover as much of the freshwater from the concentrate as possible, to minimize wasting of thenatural resource. Technologies to increase recovery or convert the concentrate into solidsalts (zero liquid discharge) using mechanical evaporators or distillation systems are discussed. Identification of appropriate methods of concentrate management is necessary fordetermining the feasibility of a reverse osmosis project.An attractive solution to the concentrate disposal issue is to convert this disposal probleminto a natural resource. The paper discusses possible beneficial uses of concentrate that include:land application or irrigation of salt tolerant crops; saline aquaculture, farming of brineshrimp or other saltwater species; restoration of brackish waterways or development ofsaltwater marshes, wetlands or habitats; energy generation using solar gradient ponds;industrial uses as feedstock or process stream; and, production of marketable salts or mineralcommodities. The selection of a concentrate disposal option depends on site-specific conditionsof the treatment plant. The variables that may affect the selection include economics, quality and quantity of concentrate, regulatory concerns, availability of the receiving site, public acceptance,and the climatic and geographical considerations. Includes 25 references, tables, figure.

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Edition: Vol. - No. Published: 03/01/2005 Number of Pages: 16File Size: 1 file , 440 KB