The California Department of Corrections and Rehabilitation (CDCR) is taking steps to improve
the water supply system for the Deuel Vocational Institution (DVI) in Tracy, California. The DVI
currently supplies potable water to the facility from three slightly brackish groundwater wells.
The groundwater has a TDS concentration of 1,150 to 2,200 mg/L, and has high concentrations
of dissolved iron and manganese. Additionally, the elevated TDS in the drinking water supply
has led to the issuance of a cease and desist order from the Regional Water Quality Control
Board due to elevated TDS in the effluent from the DVI wastewater treatment plant (WWTP).
A water system upgrade study in 2003 eliminated all alternative sources of supply and identified
reverse osmosis (RO) as the most appropriate technology for improving the quality of the DVI's
potable water. Consequently, the reduction in the potable water TDS will lower the TDS in the
wastewater. The proposed TDS limit for the WWTP effluent is 450 mg/L. A detailed analysis of
the salinity increase by potable uses at DVI established that from distribution to collection,
approximately 250 to 300 mg/L of TDS are added to the potable water. Based on this analysis,
a target potable water TDS of 100 mg/L was established as the design finished water goal for
the RO process.
As part of the water system upgrade study in 2003, all concentrate disposal options for the RO
concentrate were eliminated except for zero liquid discharge using a vapor compression brine
concentrator and evaporation ponds. The preferred disposal option, deep well injection well,
was eliminated because of failures of nearby wells and an unfavorable regulatory environment.
Insufficient land was available for solar evaporation and no options for surface water discharge
were available or permittable. Discharge to the sanitary sewer was not considered because it
directly conflicts with one of the water system improvement project goals, a reduction in the
wastewater effluent TDS.
This paper discusses the regulatory factors driving the project, the development of the proposed
treatment solutions, and the steps taken for controlling iron and manganese, demineralizing the
groundwater, disposing of the brine through a combination of brine concentration and
evaporation, and capital costs. Includes 2 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 440 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 9 |
| Published : | 03/01/2007 |
