Collections > Master's Papers > Gillings School of Public Health > Ash Management Alternatives: UNC-CH Power Plant

The University of North Carolina at.Chapel Hill is in the design phase for a replacement power plant incorporating two circulating fluidized combustion (CFC) boilers. CFC is state-of-the-art technology for combined control of sulfur dioxide and nitrogen oxide emissions which are precursors to acid precipitation. The trend toward requiring the removal of contaminants from the waste gas stream results in transfer of these pollutants to the solid waste stream. The primary goal of this study was to provide the Vice Chancellor for Business and Finance of the University of North Carolina the alternatives for management of ash to be produced by the replacement power plant. This study satisfies Conditions 9 and 10 set forth in the Special Use Permit issued to the University by the Town of Chapel Hill for the development of this project. Current and potential technological alternatives for the management of coal ash were surveyed in the technical literature and by conducting informal interviews with experts. The advantages and disadvantages of each alternative, including economic, technological and environmental considerations were discussed. Characteristics that influence the handling of ash from a fluidized bed combustion (FBC) power plant, and more specifically, from the new Circulating Fluidized Combustion (CFC) type of FBC technology are identified and discussed. A preliminary assessment is made based on data from similar plants of the environmental safety of ash from the new plant using the criteria of toxicity, leachability and corrosivity. Current and anticipated state and federal regulations regarding power plant ash are reviewed at length. Three general approaches to ash management are discussed that fit into an integrated program. The first approach is to identify alternatives for ultimate disposal of the ash. A number of scenarios are presented for various ash disposal options. The second approach is to reduce the amount of waste to be managed. This will require modeling economic conditions and making appropriate decisions to achieve the lowest feasible level of ash production. The third and final approach is to divert ash from disposal into a resource channel. This approach requires a balance of research, development, and capital against incentives of profits as well as saved disposal costs. The decreasing acceptability of landfilling as the catch-all approach to solid waste management, increasing stringency in regulation of landfill practices and the escalating cost of siting and operating a landfill will play an important part in attempting to manage the power plant waste stream.