Human and Ecological Risk Assessment - Earthjustice

Appendix BWaste Management UnitsAppendix B. Waste Management UnitsThe source models supporting the CCW risk assessment require inputs describing thecharacteristics of CCW waste management units (WMUs). To satisfy this requirement, theassessment used a data set of WMU area, capacity, liner type, geometry, and waste typemanaged for a set of individual CCW landfills and surface impoundments that are representativeof the national population of coal combustion facilities that are managing their wastes onsite.The sources for these data sets were responses to two voluntary industry surveys: anElectric Power Research Institute (EPRI) comanagement survey (for conventional utility coalcombustion WMUs units) and a Council of Industrial Boiler Owners (CIBO) fluidized bedcombustion (FBC) survey (for FBC WMUs). In addition to the individual WMU data, certainassumptions were required regarding (1) liner types and characteristics, (2) surface impoundmentoperating life, and (3) above- and below-grade geometries for WMUs. The sections belowdescribe the two industry surveys, then discuss the data sources and assumptions made.Attachment B-1 lists the 181 CCW disposal sites modeled in this risk assessment and theirlocations. Attachment B-2 presents the WMU data used in the CCW risk assessment for each ofthe 108 landfills and 96 surface impoundments at these coal combustion facilities.B.1 EPRI Comanagement SurveyFor conventional utility coal combustion WMUs, the source of data for area, capacity,liner type, and waste type managed was the EPRI Coal Combustion By-Products andLow-Volume Wastes Comanagement Survey (EPRI, 1997a). In 1995, EPRI sent a 4-pagequestionnaire to all electric utilities with more than 100 megawatts (MW) of coal-firedgenerating capacity. The survey gathered data on the design of coal combustion managementunits and the types and volumes of waste managed. From the survey responses, EPRI preparedan electronic database and provided it to EPA in support of the March 1999 Report to Congress:Wastes from the Combustion of Fossil Fuels (the RTC) (U.S. EPA, 1999a). EPRI also publisheda report (EPRI, 1997a) documenting the survey format and providing a brief summary of theresults.The EPRI survey responses include information on 323 waste management facilitiesserving 238 power plants located in 36 states. The total annual volume of CCW reporteddisposed by respondents to the EPRI comanagement survey was nearly 62 million tons. Thisquantity was two-thirds of the total generation of CCW in 1995. Therefore, the survey sampleencompasses the majority of CCW disposed in terms of volume. Based on comparison with datafrom other sources, the EPRI survey sample appears representative of the population of coalcombustion WMUs in terms of the types of units included (i.e., landfills and surfaceimpoundments). The EPRI survey sample also is believed to be generally geographicallyrepresentative of the population of conventional utility WMUs, although it may under-representcertain management practices in a few states. The EPA document, Technical BackgroundDocument for the Supplemental Report to Congress on Remaining Fossil Fuel CombustionApril 2010–Draft EPA document. B-1