CARB Research Webinar: California Landfill Gas Emissions

Having trouble viewing this email? View it as a Web page.


CARB Research Webinar: California Landfill Gas Emissions

The California Air Resources Board (CARB) and CalRecycle contracted with researchers at California Polytechnic State University, San Luis Obispo (Cal Poly) to perform a detailed assessment of greenhouse gases (GHG) (methane, nitrous oxide, and carbon dioxide), carbon monoxide, and 78 non-methane volatile organic compound (NMVOC) emissions from landfills in California. In extensive field testing, the researchers determined methane emissions using aerial measurements at 16 selected landfills and measured emissions of all 82 GHGs and VOCs from 31 individual cover types over California’s wet and dry seasons using ground-based static flux chambers at a subset of five landfills. Researchers will present results and recommended control measures that can be employed to reduce emissions. The full report is available on CARB’s Landfill Gas Research page.

Date:      Thursday, March 4, 2021
Time:      2:00 p.m. – 3:30 p.m.


Research Summary

Flux and emissions of methane, nitrous oxide, and NMVOCs are highly variable at a given landfill and also between landfills. Analyses included examining correlation of flux to various landfill characteristics and operational conditions. Cover characteristics was the main factor found to control surface flux. Researchers observed differences between aerial and ground measurements, which may be attributable to emissions from the active waste placement surface at the landfills (not measured in the ground tests) and the high uncertainties in the aerial measurements. To calculate landfill gas collection efficiencies, researchers compared multiple approaches to determining total methane generation (i.e., using the quantity of gas collected, divided by measured versus modeled generation). They found that collection efficiency may be higher or lower than modeled estimates at a given landfill. Due to large uncertainty in modeling gas generation, the use of collection efficiency as a measure of emissions may not be reliable.

Speaker Biographies

Dr. Jim Hanson is a professor of Civil and Environmental Engineering at Cal Poly. He conducts research in geotechnical engineering and geoenvironmental engineering, thermal analysis of landfills, characterization of geomaterials, performance of landfill barriers, and civil engineering education. His research spans experimental work, field analyses, and numerical modeling. He is co-editor-in-chief of the Geotechnical and Geological Engineering Journal. 

Dr. Nazli Yesiller is the Director of the Global Waste Research Institute at Cal Poly. Her background and expertise are in geotechnical and geoenvironmental engineering with special foci on containment materials and systems, thermal regime of landfills, engineering characterization and behavior of waste materials, and beneficial reuse of wastes and byproducts. Dr. Yesiller serves as the co-director of National Science Foundation Sustainable Material Management Extreme Events Reconnaissance (SUMMEER) Organization and the co-editor in chief of ASTM Geotechnical Testing Journal. 

Dr. Derek Manheim is a Lecturer in the Civil and Environmental Engineering Department and a Research Fellow in the Global Waste Research Institute at Cal Poly. He conducts research on developing and validating numerical models that describe chemical fate and transport in the environment and climate impacts of municipal solid waste landfills.

With support from CARB and CalRecycle as well as partner landfills, this research group has been conducting research on GHG generation and emissions from California landfills resulting in the largest landfill emissions databases currently available.