AWWA MTC64567

The California Department of Corrections and Rehabilitation (CDCR) is taking steps to improvethe water supply system for the Deuel Vocational Institution (DVI) in Tracy, California. The DVIcurrently 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 concentrationsof dissolved iron and manganese. Additionally, the elevated TDS in the drinking water supplyhas led to the issuance of a cease and desist order from the Regional Water Quality ControlBoard 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 identifiedreverse osmosis (RO) as the most appropriate technology for improving the quality of the DVI'spotable water. Consequently, the reduction in the potable water TDS will lower the TDS in thewastewater. The proposed TDS limit for the WWTP effluent is 450 mg/L. A detailed analysis ofthe 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 forthe RO process.As part of the water system upgrade study in 2003, all concentrate disposal options for the ROconcentrate were eliminated except for zero liquid discharge using a vapor compression brineconcentrator 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 dischargewere available or permittable. Discharge to the sanitary sewer was not considered because itdirectly conflicts with one of the water system improvement project goals, a reduction in thewastewater effluent TDS.This paper discusses the regulatory factors driving the project, the development of the proposedtreatment solutions, and the steps taken for controlling iron and manganese, demineralizing thegroundwater, disposing of the brine through a combination of brine concentration andevaporation, and capital costs. Includes 2 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

03/01/2007

Number of Pages:

9

File Size:

1 file , 440 KB