SCH Number 2016121051

Project Info

Title

Coachella Water Authority Chromium-6 Facilities Improvement Project

Description

Coachella Water Authority proposes to undertake the Chromium-6 water Facilities Improvement Project in order to comply with recently passed state of CA regulations. CWA operates six groundwater wells for its raw water supply, all of which have chromium-6 concentrations above the newly established MCL. With implementation of the project, five of the six wells will continue operating, and the sixth well will be taken offline. The five wells will be upgraded with chromium-6 removal treatment technology. Under the SBA treatment option, the SBA resin capacity for chrmium-6 will periodically diminish, and the resin will require regeneration. The proposed project also includes analysis of the construction of a new CWA resin regeneration facility located on Avenue 52 on CWA property (RRF), or at the current CSD WWTP (CRRF). The resin regeneration process involves ion exchange using sodium chloride (brine) to remove the chromium-6 from the resin beads. Resin regeneration results in a spent brine, which necessitates proper treatment and disposal. Alternatively, if a stannous chloride treatment approach is deemed feasible, CWA would upgrade the five wells with that technology. The stannous chloride treatment process involves adding stannous chloride to the water, allowing reaction time, removing the tin and chromium particles that remain with a filter. Treatment equipment includes a chemical feed system, reaction tank, and filters. Periodically, particles will accumulate and increase pressure on the filters and would need to be replaced. The stannous chloride process does not require resin regeneration and thus there would be no resin regeneration facilities for this approach.

2 documents in project