In 2015, the U.S. Environmental Protection Agency (EPA) issued a new rule addressing the handling, storage and disposal of coal combustion residuals (CCRs). CCRs are the materials that remain after coal is burned.
Four Pirkey Plant ash storage sites are included in the CCR monitoring program:
- The east bottom ash pond,
- The west bottom ash pond,
- The landfill and
- The FGD stackout area.
All storage sites are in active use. Pirkey Plant uses dry fly ash handling. Fly ash is stored in a lined landfill.
Pirkey Plant provided more than 371,000 tons of fly ash for beneficial reuse in 2017.
- Coal Combustion Residuals Monitoring & Reporting
Southwestern Electric Power Company (SWEPCO) has completed the first steps in the new groundwater monitoring program under this rule.
SWEPCO took a series of groundwater samples at the boundaries of all four ash storage sites. We took some samples before the groundwater passed beneath the ash storage sites. (The reports refer to this as up-gradient.) We took other samples after it passed beneath the sites (down-gradient). We used the data to establish baseline levels for 21 different substances in the groundwater. It is important to remember that variations in the level of these substances in groundwater are natural and occur for many reasons.
Moving forward, we will use these baselines to help determine if our ash storage sites are impacting the groundwater. We will watch to see whether there are changes in the amount of these substances before and after the groundwater flows beneath the ash storage sites. We also will watch whether levels of these substances vary from the baselines we observed.
The initial data at Pirkey Plant show potential groundwater impacts very close to our storage sites. Using appropriate sampling and analysis methods, we found differences in the amounts of boron, calcium, chloride, sulfate and total dissolved solids in certain wells before and after the groundwater passed beneath the storage sites. The rule calls these indicator substances. They are used to determine whether additional analysis is needed.
Baseline sampling in some wells showed one or more results for arsenic, beryllium, cadmium, chromium, radium and mercury above primary drinking water standards. One or more samples showing a higher concentration of a substance, even above a standard, does not mean that local drinking water is unsafe or that there is any impact from the ash storage site.
We are working to understand what the numbers mean. We will do additional monitoring and analysis to determine if there are groundwater impacts from our storage sites farther from the immediate area.
We proactively reached out and met with plant neighbors and community leaders to answer questions about the data collected so far and to discuss next steps.
Here’s how SWEPCO conducted the monitoring:
- The east bottom ash pond - six monitoring wells,
- The west bottom ash pond - six monitoring wells,
- The landfill - seven wells and
- The FGD stackout area – five wells.
- Alternate Source Reviews
Independent third parties completed Alternate Source Reviews for the four CCR storage sites at Pirkey Plant. The reviews consider other factors that could impact sampling results as the groundwater passes the CCR storage sites.
This review process did not find alternate sources for groundwater impacts at Pirkey Plant’s CCR storage sites.
- Location Restrictions – New
The CCR rule established location restrictions for coal ash storage sites. It requires that storage site locations be evaluated regarding proximity to
- Groundwater aquifers,
- Fault areas,
- Seismic zones and
- Unstable areas (example: presence of quicksand).
AEP and SWEPCO recently completed the required review of location restrictions for Pirkey Plant’s CCR storage sites. This review found that the CCR storage sites at Pirkey Plant meet all location restrictions.
- Next Steps
- SWEPCO will continue to test water from all of these wells twice each year.
- If SWEPCO determines that the ash storage site is impacting the groundwater, we will expand monitoring to show whether there are water quality impacts farther away from the storage site.
- If additional monitoring shows that changes in groundwater quality are coming from our ash storage sites, we will seek public input as we develop a mitigation plant to address these impacts.
- East Bottom Ash Pond
- FGD Stackout Area
- West Bottom Ash Pond