waste
12.01.10 2:32 PM
posted by In a letter dated November 17, 2010, Deputy Commissioner Paul Sloan, Tennessee Department of Environment and Conservation ("TDEC"), submitted formal comments to EPA concerning federal regulation of coal combustion residuals (CCR). In its proposed rulemaking notice EPA stated that federal regulation is necessary and proposed two approaches: One regulation under Subtitle C (RCRA) and the other regulation pursuant to Subtitle D (non hazardous solid waste). TDEC's letter to Lisa Jackson emphasizes that decisions should be made on good science, and that the science supports regulating coal combustion residuals under the Subtitle D approach. The letter also emphasizes that EPA's concern that it does not have oversight over Subtitle D could be addressed by having Congress enact legislation to accomplish that purpose. The actual comments are very detailed and stress that much of the basis for their comments is the experience with the failure of the coal ash impoundment at the Kingston, Tennessee facility. The comments provide a number of bullet points that are worth repeating as to the scientific basis for using subtitle D. They are worth repeating:
· CCR does not contain chemical constituents at the level of risk to public health and the environment that are present in currently defined hazardous waste. Extensive testing of coal ash using EPA approved laboratory protocols for volatile organics, polynuclear aromatic hydrocarbons and metals demonstrate the levels of these constituents are significantly lower than the levels that trigger solid waste to be characterized as hazardous waste.
CCR does not present radiological hazards.
Solids from coal ash consist primarily of silica and metal oxides. These· oxides have very limited solubility. Metal oxides in CCR present limited potential for biological uptake due to their reduced oxidation state.
EPA has evaluated CCR for designation as a hazardous waste three times. In· each case, EPA’s final decision was to continue to regulate CCR as a solid waste because it is an inert, insoluble and manageable material.
The chemical properties of CCR did not cause the failure of the TVA· Kingston coal ash landfill. Engineering analysis indicates the failure was caused by poor design, poor drainage and poor operation.
The physical properties of CCR vary greatly depending upon moisture· content, particularly for fly ash. Too little moisture and fly ash acts like sand. Too much moisture and fly ash acts like liquid. The TVA Kingston failure demonstrates that CCR must be disposed in well designed geologically stable structures
· The TVA Kingston failure disrupted lives, destroyed property and caused significant environmental damage which requires remediation. However, EPA’s total economic impact estimation of $3 billion seems overly high considering the $1.3 billion cleanup price tag and Natural Resource Damages in a currently estimated range not exceeding $20 million.
To date, the Tennessee Department of· Environment and Conservation is not aware of any adverse impact to public health caused by the chemical constituents in CCR. Oak Ridge Associated Universities and Vanderbilt University Hospital examined more than 200 Roane County residents following the TVA Kingston spill and found no adverse effects to human health due to coal ash exposure. Additionally, the Tennessee Department of Health and the federal Agency for Toxic Substances and Disease Registry did not identify any chemical toxicity health effects from coal ash.
Historical effluent data from NPDES· permitted CCR wastewater treatment impoundments clearly indicates that the metals present in the discharges are not at concentrations sufficient to pollute receiving streams. These wastewater treatment impoundments are designed to remove settleable solids from CCR wastewaters so as to protect streams from these solids and the metal constituents associated with them.
A review of groundwater monitoring data· from coal ash surface impoundments does demonstrate that in some instances where there is no synthetic or geologic liner, metals are transported via seepage from the bottom of the surface impoundments into local groundwater. However, Tennessee has not identified any specific sites where groundwater contamination from surface impoundments has impacted local, private or public water supplies. On sites where groundwater contamination has been found, the department will continue to require monitoring to be sure that any offsite impacts are prevented or mitigated.
CCR may potentially present a threat to· public health when the particle size is small, and must be managed to avoid this potential exposure pathway. If inhaled, CCR could affect the respiratory system much like small sand particles act in people with silicosis. This is because the CCR particles are small with irregular surfaces that attach to lung tissue, much like tiny grains of sand.
· CCR does not contain chemical constituents at the level of risk to public health and the environment that are present in currently defined hazardous waste. Extensive testing of coal ash using EPA approved laboratory protocols for volatile organics, polynuclear aromatic hydrocarbons and metals demonstrate the levels of these constituents are significantly lower than the levels that trigger solid waste to be characterized as hazardous waste.
CCR does not present radiological hazards.·
Solids from coal ash consist primarily of silica and metal oxides. These· oxides have very limited solubility. Metal oxides in CCR present limited potential for biological uptake due to their reduced oxidation state.
EPA has evaluated CCR for designation as a hazardous waste three times. In· each case, EPA’s final decision was to continue to regulate CCR as a solid waste because it is an inert, insoluble and manageable material.
The chemical properties of CCR did not cause the failure of the TVA· Kingston coal ash landfill. Engineering analysis indicates the failure was caused by poor design, poor drainage and poor operation.
The physical properties of CCR vary greatly depending upon moisture· content, particularly for fly ash. Too little moisture and fly ash acts like sand. Too much moisture and fly ash acts like liquid. The TVA Kingston failure demonstrates that CCR must be disposed in well designed geologically stable structures.
Comments!
Leave a Comment!
No comments yet. You should leave one!