Intelligent Bioreactor Management Information System (IBM-IS) for Mitigation of Greenhouse Gas Emissions

Abstract

Methane is an important contributor to global warming with a total climate forcing estimated to be close to 20% that of carbon dioxide (CO2) over the past two decades. The largest anthropogenic source of methane in the US is "conventional" landfills, which account for over 30% of anthropogenic emissions. While controlling greenhouse gas emissions must necessarily focus on large CO2 sources, attention to reducing CH4 emissions from landfills can result in significant reductions in greenhouse gas emissions at low cost. For example, the use of "controlled" or bioreactor landfilling has been estimated to reduce annual US greenhouse emissions by about 15-30 million tons of CO2 carbon (equivalent) at costs between $3-13/ton carbon. In this project we developed or advanced new management approaches, landfill designs, and landfill operating procedures for bioreactor landfills. These advances are needed to address lingering concerns about bioreactor landfills (e.g., efficient collection of increased CH4 generation) in the waste management industry, concerns that hamper bioreactor implementation and the consequent reductions in CH4 emissions. Collectively, the advances described in this report should result in better control of bioreactor landfills and reductions in CH4 emissions. Several advances are important components of an Intelligent Bioreactor Management Information System (IBM-IS).5 III. Executive SummaryMethane is an important contributor to global warming with a total climate forcing estimated to be close to 20% that of carbon dioxide (CO2) over the past two decades. The largest anthropogenic source of methane in the US is "conventional" landfills, which account for over 30% of anthropogenic emissions. One means of mitigating methane emissions is to operate landfills as "controlled landfills" or "bioreactors." Here, biological conditions in the waste are optimized allowing more rapid and complete waste decomposition. In "anaerobic bioreactors" methane generation is enhanced through liquid addition. High efficiency capture of methane is utilized to maximize fuel energy recovery and minimize fugitive emissions. In "aerobic bioreactors" air and liquid are introduced in the landfill and the combined effects of heat and oxygen inhibit methane formation. Both "controlled" landfill operations hold promise for mitigating fugitive methane emissions from landfills.A recent NETL sponsored economic study of anaerobic controlled landfilling estimated that such landfilling could reduce annual US greenhouse emissions by about 15-30 million tons of CO2 carbon (equivalent) at costs between $3-13/ton carbon. Given the promise of this technology, several bioreactor landfills have been constructed in the United States, although most are fieldscale research landfills. While a few commercial bioreactor landfills have been built, the waste management industry has yet to embrace this technology because of lingering concerns about the capture of fugitive greenhouse gases, how to manage liquid addition to maintain optimal moist...

Quantifying capture efficiency of gas collection wells with gas tracers

“…For example, gas tracer tests could be used near wells with or without synthetic ''boots'' to assess the impact of boot diameter and cover soil properties, e.g., thickness and soil type, on landfill gas capture. Tracer tests might also be used to quantify the effect of adjusting landfill gas well suction in response to barometric pressure changes on collection efficiency, which has been proposed to reduce landfill CH 4 emissions (Imhoff et al, 2011). Quantitative data from tracer tests would help assess the utility and cost-effectiveness of alternative cover systems, well designs and management practices.…”