The staff at SCS Engineers (SCS) has talked at length about how changing the parameters of a coal ash remediation project impacts the eventual outcome of that project. That involves not only the factors present at a particular site but also the regulatory environment in which that site operates, certainly as rules evolve regarding the disposal of coal combustion residuals (CCRs).
Two primary means of coal ash remediation are closure-in-place, or cap-in-place, of an existing coal ash storage site, and closure-by-removal. Closure-in-place involves dewatering the storage site, or impoundment, in effect converting from wet storage to dry storage of ash. A cover system is then used to prevent more water from entering the site.
Closure-by-removal involves dewatering of the coal ash, and then excavating it, and transporting it to a lined landfill or a recycling center.
“There are lots of technical reasons and site-specific factors that can influence a project’s outcome,” said Eric Nelson, vice president of SCS and an experienced engineer and hydrogeologist. “These might include the type and volume of CCR, the geologic setting [e.g., groundwater separation], presence and proximity of receptors [e.g., drinking water supply], and physical setting [e.g., constraints such as access, available space onsite for re-disposal, proximity/availability of offsite re-disposal airspace, etc.].”
Sherren Clark, an SCS team member with experience in civil engineering and environmental science, said “risk evaluation is a key component of remedy selection. A CCR unit undergoing an assessment of corrective measures [ACM] could be a 100-acre ash impoundment containing 30 feet of fly ash, but it also could be a 2-acre bottom ash pond. It could have numerous groundwater constituents exceeding drinking water standards by a significant margin, or it could have a single parameter slightly above the limit at a single well. And there could be water supply wells nearby in the same aquifer, or none for miles around. All of these factors play into the selection of a remedy that addresses the existing risks, without creating other negative impacts such as site disturbance, dust, or truck traffic.”
Tom Karwoski, a hydrogeologist and project manager for SCS who has designed and managed investigations and remediations at landfills as well as industrial, Superfund, and other waste storage sites, noted the challenges inherent to individual sites and stressed careful planning is needed to achieve the desired result. At some sites, “given the size and the nature of the impoundments, transport of CCR off-site may not be the best option.” When moving from the ACM to the remedy [selection], it’s extremely important to have multiple meetings with the client to set the schedule. Based on the way the [CCR] rule is written, things have to progress logically. There’s time available for careful planning. The last thing we want to do is start making assumptions without input from the client and other interested parties. Regulatory compliance and concern for the surrounding community and the environment are important to us and our clients.
“If the nature of the site in its current condition allows it, capping of the site will reduce surface water moving through the waste and significantly cut down on the risk of groundwater contamination,” Karwoski said. “At sites where you have CCRs that may be distributed across a site, to consolidate that onsite and then the cap will address CCRs impacting groundwater.”
Jennifer Robb, vice president and project director with SCS’s Solid Waste Services Division, and the company’s Groundwater Technical Advisor for the Mid-Atlantic region said her group has “done corrective measures for cobalt, arsenic, and thallium,” all contaminants found in coal ash. “There are some in situ bio-remediation that can be done, where basically you’re trying to alter the chemistry to immobilize the metal.” Jennifer noted that there are also more physical remedies where contaminated groundwater is extracted from the subsurface by pumping or the groundwater plume is contained or treated in-situ with the construction of “cut off trenches.”
Karwoski said, “we have no preconceived notions about what is best for all sites, but if you consolidate [waste] onsite and then cap, it will certainly take care of a lot of situations where you have CCRs impacting downgradient groundwater.” This approach may not be appropriate in every situation, but, if arrived at after thoughtfully navigating the remedy selection process defined in the current Federal CCR rules (40 CFR 257 Subpart D—Standards for the Disposal of Coal Combustion Residuals in Landfills and Surface Impoundments), should result in an approach that is effective based on the site-specific factors present.
Read last month’s blog “Many Factors Influence Remedies for CCR Control and Disposal.”
PFAS are also key components in aqueous film-forming foam (AFFF), which is used to fight petroleum-based fires at aviation and manufacturing facilities. For decades, AFFF containing PFAS has been used extensively at airports throughout the world to protect the safety of passengers, crew, and others. The FAA requires that commercial airports train with, calibrate equipment with, and use the best performing AFFF fire suppression systems. AFFF is required to be used at airports and must be certified to meet strict performance specifications, including those mandated by the U.S. Department of Defense Military Specifications.
Lynleigh Love and Chris Crosby of SCS Engineers discuss the risks and issues with PFAS-based firefighting foam used at airports. The authors cover the regulatory climate, contamination investigations, operational and environmental management and litigation, along with alternatives to using traditional AFFF. There are some possible alternatives that can mitigate health risks in your community.
According to the U.S. Geological Survey Circular 1344, the United States uses 79.6 billion gallons per day of fresh groundwater for public supply, private supply, irrigation, livestock, manufacturing, mining, thermoelectric power, and other purposes. This blog is intended for businesses that must meet groundwater monitoring regulatory compliance according to EPA and state mandates, which are becoming increasingly stringent.
Have you had a regulatory compliance issue due to the condition of your groundwater monitoring wells or adequacy of your monitoring network? Are you confident compliance issues won’t arise in the future? Groundwater monitoring networks—including wells and dedicated sampling equipment—are often:
What if you managed your groundwater monitoring network like your other equipment assets? By taking a systematic asset management approach to maintaining your groundwater monitoring network you can:
Not concerned? Consider the likely results of the “if it ain’t really broke, don’t fix it” approach:
Regulatory Non-Compliance: Failure to comply with state and federal monitoring well regulations may result in a notice of non-compliance, fines, or legal action.
Repair and Maintenance Costs: Ignoring minor repairs and maintenance can lead to significant well repair or replacement costs. Simple repairs like lock replacement or ground surface seal repair are quick and low cost. Don’t let these minor items put you at risk for notification of non-compliance due to neglect. Other repairs such as protective casing or near-surface well casing repair may cost more but are a fraction of the cost of replacing a well that becomes unstable due to neglect.
Well Replacement Costs: Abandoning and replacing a single well that can no longer be repaired can cost $3,000 to $10,000+ depending on the depth and construction of the well.
As with many assets, you save time and money in the long run by addressing problems before they arise. So what does monitoring well asset management look like? It doesn’t have to be complicated, costly, or time-consuming. We recommend starting with a simple inventory following these basic steps:
1. Identify needed repairs and replacements of existing wells
2. Develop a plan to repair, replace, or abandon wells as needed
3. Identify deficiencies in the coverage of your well networks
Schedule inventory Steps 1-3 yearly. Download SCS Engineers’ useful well inspection checklist to record monitoring well conditions, identify well maintenance needs and identify the regulatory status of each well. Your trained staff or your environmental consultant can perform the yearly well inventory.
Contact SCS at email@example.com for a groundwater expert near you.
About the Authors: Tom Karwoski, PG, has 30 years of experience as a hydrogeologist and project manager. He has designed and managed investigations and remediations at existing and proposed landfills; and industrial, Superfund, military, and petroleum sites. Mr. Karwoski was a hydrogeologist with the Wisconsin Department of Natural Resources prior to becoming an environmental consultant.
Meghan Blodgett, PG is a project professional with over eight years of experience in the environmental consulting field, including soil, groundwater, and soil vapor investigation and remediation; brownfield redevelopment; and solid waste landfill development. She is experienced in planning and performing soil and groundwater contamination investigations, monitoring well design and installation, hydraulic aquifer testing, and soil and groundwater sampling.
The Wisconsin Department of Natural Resources (WDNR) Waste and Materials Management Study Group (WMMSG) met August 16. Here are three key updates from the meeting.
The 2014 guidance “Reducing or Terminating Groundwater Monitoring at Solid Waste Landfills” is under review. The Groundwater Monitoring subgroup completed recommendations for revision. The key proposed revisions include:
The subgroup’s recommendations will be reviewed by WDNR staff, and then sent out for public comment before finalizing.
Alternative Landfill Caps
The Alternative Landfill Caps subgroup has developed a draft list of recommendations that include the following:
The subgroup is making another round of edits to the recommendations before they are presented to WDNR staff for review and comment. Track updates on WDNR’s WMMSG web page.
Research, Development, and Demonstration (RD&D) Rule
The RD&D rule was also discussed at the last meeting, partly in relation to alternative capping options. To be consistent with federal rules, WDNR is considering revising the current Wisconsin RD&D rule (NR 514.10) to allow up to six renewals (up to 3 years each) of an RD&D Plan. This would extend the total RD&D test period to 21 years, an additional 9 years from the current 12 years allowed. With the RD&D rule reaching the 10-year mark, some sites are seeing the 12-year finish line on the horizon. WDNR cautions that the rulemaking process takes time.
More About the Waste and Materials Management Study Group
The study group provides the Waste and Materials Management Program with constructive feedback on policy and technical issues and works collaboratively with WDNR staff to find workable solutions. Find more information, meeting dates, agendas, and meeting minutes here.
For questions about how the study group impacts your solid waste operations, contact: