California Water Service Company had acquired another water company with approximately 100 connections, in Porterville, California, located in a remote agricultural area of the Central Valley. Their annual well testing had shown levels of nitrate at or near the Maximum Contamination Level (MCL) of 45 ppm and perchlorate was found in the groundwater at levels above the Public Health Goal (PHG) of 10 ppb. A treatment system was needed to remove both these contaminants to ensure quality potable water for the local community.
Evoqua Water Technologies 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.
The service-based solution significantly reduces the amount of manpower that the water company needs to maintain for site operation. The nitrate treatment system uses off-site regeneration at an Evoqua facility that reduces overall operating costs for treatment of the nitrate and eliminates generation of any liquid or solid waste stream at the site. The financial arrangement for this project allowed the water company to plan their costs over a 10 year period versus the capital investment necessary to install a new treatment system.