XDD Environmental has expanded our scope of remedial services to include the remediation of coal combustion residual (CCR) impacts in groundwater.
XDD uses our state-of-the-art treatability laboratory to test several processes associated with reducing concentrations of dissolved and total metals for potential treatment either in situ or above ground. Several processes can be evaluated based on the following factors:
- Efficiency/Cost: The treatment train has to be cost effective relative to alternative treatment options like landfilling.
- Kinetics: System processes must have kinetics that are rapid enough to avoid the need for large on-site reaction containers.
- Treatment: CCR commonly have a diverse mix of metals, including boron, arsenic, molybdenum, and barium. These metals often have to meet stringent groundwater or surface water discharge standards.
Example Treatment Process:
Once the treatment process has been evaluated, XDD services include both pilot testing and full-scale implementation. XDD is in the process of completing a pilot operation at Ameren’s Rush Island Energy Center to validate the treatability results and gain information for full-scale design. The pilot system uses a series of extraction wells to control groundwater emanating from below the CCR ash pond. The extracted groundwater is treated and then re-injected to create linear hydraulic control with zero-net difference to the flow rate or direction.
Since installation, the Rush Island pilot system has been running continuously for several months and has demonstrated the ability to meet Missiouri Department of Natural Resources permit requirements (quantified by monthly sampling) by reducing metals concentrations by up to 99%.
| Dissolved Metal | Influent (ppb) | Effluent (ppb) |
|---|---|---|
| Barium | 76.3 | 10.6 |
| Boron | 7,940 | < 20 |
| Molybdenum | 880 | 10 |
| Arsenic | 163 | 1.6 |
| Lead | 11.3 | < 1.0 |
Currently, XDD is finalizing the full-scale design for the Rush Island Energy Center with the goal of implementation in 2021. Concurrent, XDD is performing treatability studies and pilot test design for similar systems at two other Ameren sites. For a full description of the Ameren project visit here and here.
XDD’s process can work for any site with metals contamination to groundwater, please feel free to reach out to info@xdd-llc.com if you have any questions.