Response of compost biocover to freeze-thaw cycles: Column experiments

• Behaviour of compost biocover under freeze-thaw conditions studied
• Freeze-thaw cycles have effects on the behaviour.
• Methane removal efficiency can be reduced by freeze-thaw conditions.
• Effects are limited to the upper biocover layers.

The microbial oxidation of methane in biocover is considered a promising technology for the mitigation of methane emissions from landfills. In the present paper, the behaviour (evolution of methane and oxygen concentration, volumetric water content and temperature) and performance under freeze-thaw cycles (FTCs) conditions are investigated by column experiments. In the utilizing of column experiments, three columns are developed, manufactured, prepared and treated by a period of methane injection (0 FTC), after 1 FTC and 2 FTCs, in three respective stages. One column is instrumented with various sensors to monitor the evolution of temperature, volumetric water content, settlement and gas composition at four different depths for one of the biocover columns. In addition, laboratory testing is carried out on the biocover samples with regards to their organic content and grain size distribution. The results show that two FTCs have effect on the methane removal of compost biocover as well as influence the evolution of the volumetric water content, temperature, settlement, gas composition and organic content of the biocover. However, these effects and influence are more significant in the upper layers (≤ 15 cm) of the compost biocover column. The results presented in this paper will contribute to a better design of landfill biocovers in cold regions.