Rapidly increasing water demands and limited water resources are motivating
municipalities, such as Las Vegas, to evaluate beneficial use of more difficult to treat
water 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 of
Nevada due to its salinity, the need for construction dewatering, its impact on existing
structures, and its water quality impacts on the Las Vegas Wash and Lake Mead. In an
effort to augment the potable water supply and reduce geologic hazard, Southern Nevada
Water Authority (SNWA) identified the shallow groundwater system as a potential
source 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 brine
disposal to zero liquid discharge options, i.e. solar ponds or brine treatment. Desalination
with reverse osmosis (RO) membranes and vapor compression distillation (VCD) of the brine was the
highest rated treatment alternative in the prepilot study.
A subsequent pilot study was conducted to evaluate the feasibility of RO and VCD
treatment. A concurrent desktop study was executed to compare the performance and cost
of treatment alternatives to those established for RO in the pilot study. Several of the
alternatives included treatment processes ahead of RO to reduce hardness and increase
RO recovery, and each was evaluated with VCD to achieve zero liquid discharge. The
alternatives were as follows:
softening followed by RO;
high efficiency reverse osmosis (HERO(TM)), a patented process by
Aquatech; and,
electrodialysis reversal (EDR).
The results of the RO pilot study and the desktop study of treatment alternatives are
reported in this paper. Includes tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 440 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 24 |
| Published : | 06/15/2003 |
