The South Archibald Plume Cleanup Project (SAPCP) is being implemented under a Cleanup and Abatement Order (CAO) to alleviate teracholoroethylene (TCE) contamination, as well as 1,2,3-TCP, percholorate, and hexavalent chromium in groundwater under a portion of Ontario, California. The Chino Basin Desalter Authority (CDA) recently selected Civiltec Engineering to improve its groundwater treatment as part of this project.
CDA currently operates 22 groundwater production wells and is in the process of developing new wells. With the new wells and construction of expanded pipelines, CDA anticipates delivering approximately 10,950 gallons per minute (GPM) – or 15.77 million gallons per day (MGD) – of raw water to the Chino Desalter II Treatment Plant for the treatment of volatile organic compounds (VOCs). Among the VOCs, TCE is the primary concern – at least three CDA wells will be impacted by TCE exceeding the maximum contaminant levels of 5 micrograms per liter (ug/L).
At the CDA Desalter II Treatment Plant, raw water is treated through either a reverse osmosis process or an ion-exchange nitrate removal process. The reverse osmosis system has a treatment capacity of 12.5 MGD utilizing all treatment trains. This flow includes CDA’s anticipated production of 8.64 MGD of VOC-contaminated raw water from the three new wells.
Civiltec is tasked with evaluating the existing treatment process in relation to TCE removal, as well as determining and designing the necessary modifications to the system. The improvements will remove TCE via air stripping to an effluent concentration that meets the requirements of the CAO, CDA’s Remedial Action Plan, and State and Federal drinking water standards.
The team’s modifications consider two options for the treatment of TCE: replacing existing decarbonators with air stripping towers, or installing an air stripping tower with granular carbon absorbers. In the first option, a new air stripping system can be designed to treat six to 15 MGD of flow utilizing one to three air strippers, and all 10,950 GPM flow can be processed. The second option assumes that the raw water will have a higher concentration of TCE and considers installing two carbon absorbers and an air stripping tower by removing existing decarbonators.
Shem Hawes leads Civiltec’s analysis and design efforts as Project Manager, and Bed Dawadi as lead technical strategist and design engineer. Terry Kerger will serve as a key technical advisor to project conceptualization and Sky Younger will execute the electrical engineering component.
Civiltec kicked off this project in August 2018. Final plans and specifications are scheduled to be completed by the end of the year.