NGWA Event and Education Recordings Archive

The 2012 NGWA Outstanding Groundwater Project Award: Hexavalent Chromium Removal from Drinking Water: from Desktop to Implementation at Glendale, California

In 2001, the City of Glendale, California sought to reduce hexavalent chromium in its groundwater to less than 5 µg/L (compared with a California regulatory standard of 50 µg/L), due to community concerns about the compound. At the time, no technology had been proven in flow-through drinking water treatment systems to achieve these cleanup levels. In response, a decade long program was developed, the Advanced Water Treatment Research Program for Hexavalent Chromium in Drinking Water at the City of Glendale (City), to provide technical feasibility and cost information for removing hexavalent chromium from the City’s and other utilities groundwater supplies. The project involved three phases, including: • Phase I – Bench Study, during which a broad range of technologies were screened in the laboratory; • Phase II – Pilot Study, where seven promising technologies were pilot tested at the City; and • Phase III – Demonstration Study, during which weak base anion (WBA) exchange treatment and reduction/coagulation/filtration (RCF) were demonstrated at full scale. The project has demonstrated the capability of removing hexavalent chromium through WBA resin and RCF. Pilot studies continue to assess additional anion exchange resins and adsorptive media. The WBA demonstration system continues to treat over 400 gallons per minute (gpm) from one of the City’s wells. This presentation will provide an overview of technologies demonstrated at the City to remove total and hexavalent chromium from their groundwater to low concentrations, which were provided to the State of California to assist in their determination of a Cr(VI) MCL expected in July 2013. This presentation is expected to provide practical guidance to systems that may need to consider implementing treatment to remove hexavalent chromium from water sources.