Full Description

Brine disposal for inland desalination is a daunting challenge due to the lack of the options that aretypically available for coastal communities. In addition, a desert community such as Southern Nevadamust consider alternatives for recovery of water from all treatment processes. The Virgin and MuddyRivers were evaluated by Southern Nevada Water Authority (SNWA) as a new potable water source for a70 mgd treatment facility. These waters pose extremely challenging water quality conditions. High levelsof inorganics, metals, total dissolved solids, and other contaminants require use of advanced treatmentmethods, such as reverse osmosis, to meet state and federal treatment standards. Brine production,handling, and disposal is clearly a key consideration for SNWA and was carefully evaluated during thecourse of SNWA's investigation into use of these water sources.Because of the need for complex treatment processes and the difficulty of residual discharge, innovativeand ingenious options were analyzed to meet water quality standards and provide the project recovery rateof at least 92%. Various processes were evaluated, including multi-stage reverse osmosis (RO), mid-stage ion exchange,and/or lime softening for optimizing recovery. Zero discharge options were developed and, as expected,brine disposal was found to be the highest cost for the plant. Even though the Nevada climate is ideal forbrine evaporation, the anticipated brine flow rate of 5 mgd resulted in brine disposal capital costs between$130 million to $500 million.Developing a near zero liquid discharge facility requires understanding the relationship among the variousavailable treatment options and brine disposal options. This paper describes the advantages,disadvantages, costs and methods of application which were analyzed for the Virgin and Muddy Rivers.Treatment schemes evaluated in this project will advance the database of projects available to utilitieslooking at challenging water sources in arid climates and striving for zero liquid discharge. Includes table, figures.

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Edition: Vol. - No. Published: 03/01/2007 Number of Pages: 15File Size: 1 file , 750 KB