HR: 0830h
AN: GC31B-0180    [PDF]
TI: Controlled Landfill Project in Yolo County, California for Environmental Benefits of Waste Stabilization and Minimization of Greenhouse Gas Emissions
AU: Yazdani, R
EM: ryazdani@dcn.davis.ca.us
AF: Yolo County Public Works, 292 West Beamer, Woodland, CA 95695
AU: * Augenstein, D
EM: iemdon@aol.com
AF: I E M, 4277 Pomona Avenut, Palo Alto, CA 94306
AU: Kieffer, J
EM: jeff.kieffer@ccm.yolocounty.org
AF: Yolo County Public Works, 292 West Beamer, Woodland, CA 95695
AU: Cohen, K
EM: KAREN.COHEN@netl.doe.gov
AF: National Energy Technology Laboratory, 626 Workmans Mill Road, Pittsburgh, PA 15236
AB: The Department of Public Works of Yolo County, California, USA has been testing an advanced approach to landfill bioreactors, controlled (or "enhanced") landfilling, at its Yolo County Central Landfill site near Davis, CA, since 1994. Overall objectives have been the management of waste landfilling for: (1) rapid completion of total gas generation; (2) maximum, high-efficiency gas capture; (3) waste volume reduction; and (4) maximum greenhouse gas and carbon sequestration benefits. Methane generation is controlled and enhanced through carefully managed moisture additions, and by taking advantage of landfill temperature elevation. The generated landfill methane, an important greenhouse gas, is recovered with high efficiency through extraction from a porous recovery layer beneath a surface geomembrane cover. Instrumentation included a total of 56 moisture and 15 temperature sensors in the two cells, gas flow monitoring by positive displacement gas meters, and accurate quantification of liquid inputs and outputs. Gas composition, waste volume reduction, base hydrostatic head, and a range of environmental compliance parameters has been monitored since 1995. Partitioning gas tracer tests using the injection of two gases at dilute concentrations in the landfill have also been initiated to compute the fraction of pore space occupied by water between the points of tracer injection and tracer measurement. There has been rapid waste volume reduction in the enhanced cell that corresponds to the solids' reduction to gas. Monitoring is planned for the next several years, until stabilization parameters are determined complete. Encouraging performance is indicated by: (1) sensor data; (2) gas generation results; (3) data from landfill cores; and (4) decomposition-related indicators including rapid volume reduction. When data are synthesized, project results have attractive implications for new approaches to landfill management. Over seven-years, methane recoveries have averaged over fivefold the "typical" values for comparable landfill waste. In terms of "greenhouse benefit," fractional VOC and methane energy recovery are estimated to exceed 90%, with corresponding methane and VOC emission reductions. Analyses done for the greenhouse gas mitigation program of the U.S. Department of Energy National Energy Technology Laboratory indicate favorable economics justified on landfill life extension, as well as environmental benefits. The "controlled landfill" project findings suggest potential for low-cost mitigation of waste greenhouse methane emissions, maximum landfill carbon sequestration, and maximization of beneficial energy capture from landfills. Details and results obtained since 1994 will be presented.
DE: 0322 Constituent sources and sinks
DE: 0330 Geochemical cycles
DE: 1610 Atmosphere (0315, 0325)
DE: 1615 Biogeochemical processes (4805)
DE: 1699 General or miscellaneous
SC: Global Climate Change [GC]
MN: 2003 Fall Meeting