Five Things To Know if EPA Reclassifies CCR's As Hazardous Waste

(PowerGen Worldwide 7-26-2010) Coal combustion residuals currently are not classified as hazardous waste, however, that is likely to change soon. The U.S. Environmental Protection Agency proposes to regulate CCRs under the Resource Conservation and Recovery Act to address risks from CCR disposal at electric utilities and independent power producers. The agency is considering two options and proposing two alternative regulations, one of which would regulate CCRs under subtitle C of the act, and the other under subtitle D. The solid waste industry went through something similar in the 1990s when EPA developed new requirements for municipal waste combustor ash handling and disposal. 
 
No matter which option EPA selects, utilities face a changing regulatory environment and have an array of potential courses of action to consider. These actions range from dredging, capping and remediating ash ponds, to investigating groundwater, to designing or decommissioning disposal sites. Utilities will need to manage CCR from the time it stops being coal through the time the disposal facility is capped or remediated. Perhaps most importantly, they need to think about managing the associated risks. The following list, while not intended to be comprehensive, comprises areas that will require particular attention. 
 
Structural stability and enhancement. Along with considering reclassification, EPA is studying the structural integrity of existing CCR impoundments, including plans to address safety. This affects more than 500 surface impoundments at more than 200 U.S. facilities. Necessary stability assessments should include:
 
• Gathering all pertinent information to understand the impoundment’s history; 
• Developing a general characterization including geologic, geotechnical, hydrologic and hydraulic components; 
• Estimating the engineering properties of ash, embankment and foundation materials;
• Developing seepage and stability models;
• Evaluating seepage and stability for the full range of conditions that may occur; and
• Calibrating modeling results with impoundment behavior and observed conditions.
 
Right now, the focus is on evaluating immediate risks and needs. Utilities may wish to implement short-term structural enhancement measures while tracking regulatory development and planning longer-term actions. For example, immediate water quality issues may need to be addressed, while the utility evaluates potential issues around closing or decommissioning facilities.
 
Water quality mitigation, leachate treatment and management. The specific nature of CCR leachate/wastewater varies depending on characteristics of the source coal and co-fired materials and the specific process or technology used. The route of exposure, along with physical and chemical characteristics of the receiving water/aquifer, affects CCR fate and transport and interaction with the biological community. Mobilization and fate of CCR pollutants in groundwater is controlled by complex geochemical and biological processes that vary both temporally and spatially. Geochemical modeling is an important component of fate and transport modeling. Leaching tests and modeling should be used to simulate geochemical conditions throughout the post-closure care period. Waste characteristics and water volume influence leachate quality and mobilization of CCR-derived metals. Evaluating proximity to sensitive environmental receptors should include an environmental and ecological risk assessment.
 
Closure and Decommissioning. Closing or decommissioning an ash pond encompasses many technical and environmental issues. First, the plant manager should determine whether the material will need to be removed and disposed of elsewhere, and whether it can be recycled.
 
If removal is not required or desired, an approved closure plan and/or cap must be negotiated with the state regulatory agency. Environmental monitoring and future use will also need to be worked out with the regulators. Environmental impacts will need to be evaluated and assessed, and a remediation plan developed. The potential for long-term monitoring will also need to be considered.
 
Systems Retrofit or Replacement. New regulations are expected to drive the need for operating coal plants to retrofit their existing ash handling and disposal systems. The retrofit challenge is further complicated by the need to maintain plant operations on multiple units with shared CCR handling facilities. First steps in retrofitting a facility include studying options, selecting an approach and defining the operating basis for installation. A design basis document should incorporate reliability, redundancy, value engineering and other plant O&M considerations. Other key steps include preparing a conceptual plant arrangement and flow diagram and establishing tie-in points and/or boundaries for the retrofit installation. Developing a budget for installed cost estimates, project milestone schedule and construction plan are also critical to the success of a retrofit project.
 
Risk assessment and management. Utility managers face a delicate balancing act. They must respond to immediate risk-related concerns without overstepping or underestimating emerging regulatory requirements. As management formulates a response, technical/operational “fixes” must be understood in light of shifting risks and addressed from a financial perspective. 
 
Forecasts underlying these decisions often take the form of a single expected outcome. Limitations of such a forecast are clear—while it may provide the single best statistical estimate, it offers no information about the range of other possible outcomes and associated probabilities. The problem becomes acute when there is uncertainty about the forecast’s underlying assumptions. Such is the case with CCR, where uncertainty surrounds impoundment facility condition, leachate movement, material classification, transport, reuse and disposal. 
 
Even when different scenarios are considered, a best case may assume that most underlying assumptions will deviate in the same direction from their expected value. In reality, the likelihood that all factors will simultaneously shift in the same direction is remote. 
 
Another common approach is sensitivity analysis, in which key forecast assumptions such as leaching issues are varied one at a time to assess their impact. The problem with this approach is that they are often varied by arbitrary amounts. A more serious concern is that in real life, assumptions don’t vary one at a time, so leaching issues may be exacerbated by stakeholder concerns and regulatory changes. 
 
Risk analysis provides a way around these problems. It helps avoid the lack of perspective in high and low cases by measuring the probability that an outcome will actually occur. This is accomplished by attaching ranges (probability distributions) to forecasts for each input variable. It allows all inputs to be varied simultaneously within their distributions, avoiding the problems inherent in conventional sensitivity analysis. It also recognizes interrelationships between variables and their associated probability distributions. 
 
Risk analysis is particularly relevant when dealing with costs that could result from damage to the environment. When such damage (or potential for damage) occurs, it is often not accounted for in cost-benefit decisions, which tend to overlook such negative externalities. Given utility management’s concern with regard to CCR-related risk and the possibility of liability from external negative impacts, the value of that liability should be addressed when developing a business case.
 
Indirect and external estimates are subject to uncertainty because prices or values of risk are not directly observable. Risk analysis addresses this uncertainty through a careful assessment of the nature and degree of risk; providing estimate bounds and risk ranges; confirming the analytical approach and data inputs with subject matter experts and stakeholders, and simulating variables for each alternative solution. 
 
Assessing risk gives utility management the benefit of a detailed examination of alternatives including probability of outcomes as well as related costs and benefits. Management will be equipped to formulate or shift strategies as requirements emerge. Management will also be able to use this information to explain the business merits of their risk mitigation or adaptation plans in monetary terms to both regulators and stakeholders. 
 
Conclusion
While many utilities are adopting a wait and see approach with regard to EPA’s proposed regulations, there are steps they can take now to assess immediate risk. It’s also not too early to start evaluating potential long-term courses of action.
 
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