Geosynthetics for CCR Containment and Closure
New federal regulations on the disposal of coal combustion residuals represent new approaches in response to events where coal ash has been inadvertently released from impoundments, the blowing of contaminants into the air and the leakage of potential contaminants into groundwater.
“The rule establishes technical requirements for landfills and surface impoundments under Subtitle D of the Resource Conservation and Recovery Act (RCRA), the nation’s primary law for regulating solid waste,” the agency has said. “EPA carefully evaluated more than 450,000 comments on the proposed rule, testimony from eight public hearings, and information gathered from three notices soliciting comment on new data and analyses.”
Structural integrity criteria and assessments
The impetus for the regulations was the 2008 impoundment breach at the Tennessee Valley Authority’s Kingston Fossil Plant. The new rules establish structural integrity criteria for surface impoundments as well as requirements for periodic assessment of structural integrity.
These include conducting assessments of the damage that would occur if there was a failure; assessments to document whether design, construction, operation and maintenance are consistent with accepted engineering practices; and documentation of whether the facility meets minimum standards for safety.
Protections for the air and water
The rules require surface impoundment operators to develop a fugitive-dust plan with dust-control measures for each site. Such measures include keeping coal ash in an enclosure; employing a water-spraying or fogging system; and using wind barriers, compaction, or vegetative covers. Operators must keep a log of citizen complaints about fugitive dust and prepare an annual report detailing the controls used, any citizen complaints received, and a summary of corrections made.
The leaking of potential contaminants from surface impoundments into groundwater is addressed through new requirements for:
- Groundwater cleanup
- Groundwater monitoring
- Liners for new surface impoundments and landfills as well as restrictions on their location
- Closure of unlined surface impoundments , fail to meet engineering and structural standards, and those located too near a drinking water source
- Proper closure of surface impoundments and landfills that will no longer receive coal ash.
As the power industry implements techniques similar to those utilized in the municipal solid waste market, it will no doubt adopt that industry’s use of geosynthetic membrane covers as they protect groundwater and reduce dust.