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Rush Island Energy Center Basin Groundwater Pilot System

Ameren Missouri, with consultant XDD Environmental, developed a groundwater treatment system to remove trace metals from coal ash in groundwater at the Rush Island Energy Center. The process starts by treating extracted groundwater in a series of tank vessels. Once the metals are removed, the treated water is reinjected via wells back into the aquifer. This innovative technology is the first of its kind in the nation to be used at coal ash basins and reduces metal concentration by up to 99%.

The system is designed to capture groundwater at the basin perimeter and removes arsenic, molybdenum, boron and other metals to meet the permit issued by the Missouri Department of Natural Resources (MDNR). The permit also requires that the treated water meets federal Safe Drinking Water Standards (SDWS). Once returned, the treated water has lower metal values than naturally occurring levels in the area. The below results show how effective the treatment is in removing metals.

Permit Compliance Sampling

Ameren Missouri and XDD worked for several years on treatability studies to determine the most effective method to meet CCR compliance. Lab studies using soil and water from the site allowed XDD to formulate a series of methods that have successfully removed the metals to meet regulatory requirements. A pilot system was constructed in 2020 and delivered to the site in January 2021. The system began reinjection of water into the aquifer in February 2021, after successfully meeting permitting requirements.

CCR XDD Process Diagram

With a successful pilot in operation, Ameren Missouri will install a full-scale system at Rush Island in 2021 and is evaluating implementation of this technology at its other sites. Monthly reports are submitted to MDNR, ensuring the system meets and maintains the permit standards.

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