Siemens reduces nitrate, perchlorate in Cal Water rural wells
California Water Service Company acquired another water company responsible for a small community drinking water system located in a remote agricultural section of the California Central Valley with about 100 connections. Annual well testing showed elevated levels of nitrate near the MCL due to nearby citrus orchards. Perchlorate also was found in groundwater above the public health goal. Siemens Water Technologies employed two ion exchange solutions to remedy the problem...
WARRENDALE, PA, Feb. 22, 2007 -- California Water Service Company acquired another water company responsible for a small community drinking water system located in a remote agricultural section of the California Central Valley with approximately 100 connections. Annual well testing showed levels of Nitrate at or near the Maximum Contamination Level (MCL) of 45 ppm NO3. The nitrate contamination is suspected to be due to agricultural run off related to citrus production in the area. Perchlorate was also found in the groundwater at levels above the Public Health Goal (PHG) at 10 ppb.
The water company quickly placed the community on a bottled water supply while they investigated a number of remediation treatment options including a variety of ex-situ remediation treatments such as biological and on site regeneration of resin. These options were rejected because they produced a waste stream that could not be disposed of conveniently.
Siemens provided a unique treatment system where the water is first treated for removal of perchlorate using single use ion exchange resin and then nitrate removal with a traditional regenerable ion exchange media. However, since the water purveyor could not handle on site waste streams the Nitrate removal resin is regenerated off site. The resin is sluiced in and out of the fixed tanks using a closed process that ensures the cleanliness of the media and complies with State Health Department sanitization requirements for ion exchange resins.
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