TY - JOUR
T1 - Effects of thermal boundary condition on methane oxidation in landfill cover soil at different ambient temperatures
AU - Feng, S.
AU - Leung, A. K.
AU - Liu, H. W.
AU - Ng, C. W.W.
AU - Zhan, L. T.
AU - Chen, R.
PY - 2019/11/20
Y1 - 2019/11/20
N2 - Microbial aerobic methane oxidation (MAMO) has been considered as an environmental-friendly method for mitigating methane emission from municipal landfill sites. Soil column has in a landfill cover under one-dimensional (1-D) condition. However, most of the published soil column tests failed to simulate 1-D heat transfer due to the use of thermal conductive boundary at the sidewall. In the present study, a heavily instrumented soil column was developed to quantify the effects of thermal boundary condition on the methane oxidation efficiency under different ambient temperatures in landfill cover soil. The sidewall of the soil column was thermally insulated to ensure 1-D heat transport as would have been typically expected in the field condition. Two soil column tests with and without thermal insulation were conducted at a range of controlled ambient temperatures from 15 to 30 °C, for studying how soil moisture, matric suction, gas pressure, soil temperature and gas concentration evolve with MAMO. The test results reveal that ignoring thermal insulation in a soil column test would result in a greater loss of soil heat generation by MAMO and hence oxidation efficiency by up to 100% for the range of temperature considered. When the ambient temperature increased to 30 °C (but less than the optimum temperature for MAMO), the MAMO efficiency increased abruptly at first but then decreased substantially with time, and this is likely due to the accumulation of biomass generated by MAMO.
AB - Microbial aerobic methane oxidation (MAMO) has been considered as an environmental-friendly method for mitigating methane emission from municipal landfill sites. Soil column has in a landfill cover under one-dimensional (1-D) condition. However, most of the published soil column tests failed to simulate 1-D heat transfer due to the use of thermal conductive boundary at the sidewall. In the present study, a heavily instrumented soil column was developed to quantify the effects of thermal boundary condition on the methane oxidation efficiency under different ambient temperatures in landfill cover soil. The sidewall of the soil column was thermally insulated to ensure 1-D heat transport as would have been typically expected in the field condition. Two soil column tests with and without thermal insulation were conducted at a range of controlled ambient temperatures from 15 to 30 °C, for studying how soil moisture, matric suction, gas pressure, soil temperature and gas concentration evolve with MAMO. The test results reveal that ignoring thermal insulation in a soil column test would result in a greater loss of soil heat generation by MAMO and hence oxidation efficiency by up to 100% for the range of temperature considered. When the ambient temperature increased to 30 °C (but less than the optimum temperature for MAMO), the MAMO efficiency increased abruptly at first but then decreased substantially with time, and this is likely due to the accumulation of biomass generated by MAMO.
KW - Biomass accumulation
KW - Microbial aerobic methane oxidation
KW - Soil column tests
KW - Temperature effects
KW - Thermal boundary condition
KW - Unsaturated soil
UR - http://www.scopus.com/inward/record.url?scp=85069689099&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2019.07.108
DO - 10.1016/j.scitotenv.2019.07.108
M3 - Article
C2 - 31351291
AN - SCOPUS:85069689099
VL - 692
SP - 490
EP - 502
JO - Science of the Total Environment
JF - Science of the Total Environment
SN - 0048-9697
ER -