AWWA ACE58249

Rapidly increasing water demands and limited water resources are motivatingmunicipalities, such as Las Vegas, to evaluate beneficial use of more difficult to treatwater sources. Approximately 20% of the Las Vegas Valley is underlain by shallow,often brackish groundwater that has been designated a geologic hazard by the State ofNevada due to its salinity, the need for construction dewatering, its impact on existingstructures, and its water quality impacts on the Las Vegas Wash and Lake Mead. In aneffort to augment the potable water supply and reduce geologic hazard, Southern NevadaWater Authority (SNWA) identified the shallow groundwater system as a potentialsource of potable water in its 1994 Integrated Resource Plan (IRP).A prepilot study was conducted to compare alternatives for treatment and brine disposal.It was assumed that local regulations and the lack of an ocean outfall would limit brinedisposal to zero liquid discharge options, i.e. solar ponds or brine treatment. Desalinationwith reverse osmosis (RO) membranes and vapor compression distillation (VCD) of the brine was thehighest rated treatment alternative in the prepilot study.A subsequent pilot study was conducted to evaluate the feasibility of RO and VCDtreatment. A concurrent desktop study was executed to compare the performance and costof treatment alternatives to those established for RO in the pilot study. Several of thealternatives included treatment processes ahead of RO to reduce hardness and increaseRO recovery, and each was evaluated with VCD to achieve zero liquid discharge. Thealternatives were as follows:softening followed by RO;high efficiency reverse osmosis (HERO(TM)), a patented process byAquatech; and,electrodialysis reversal (EDR).The results of the RO pilot study and the desktop study of treatment alternatives arereported in this paper. Includes tables, figures.

Product Details

Edition:

Vol. - No.

Published:

06/15/2003

Number of Pages:

24

File Size:

1 file , 440 KB