Evaluation of methane oxidation activity in waste biocover soil during landfill stabilization

Biocover soil has been demonstrated to have high CH 4 oxidation capacity and is considered as a good alternative cover material to mitigate CH 4 emission from landfills, yet the response of CH 4 oxidation activity of biocover soils to the variation of CH 4 loading during landfill stabilization is poorly understood. Compared with a landfill cover soil (LCS) collected from Hangzhou Tianziling landfill cell, the development of CH 4 oxidation activity of waste biocover soil (WBS) was investigated using simulated landfill systems in this study. Although a fluctuation of influent CH 4 flux occurred during landfill stabilization, the WBS covers showed a high CH 4 removal efficiency of 94–96% during the entire experiment. In the LCS covers, the CH 4 removal efficiencies varied with the fluctuation of CH 4 influent flux, even negative ones occurred due to the storage of CH 4 in the soil porosities after the high CH 4 influent flux of ∼137 g m −2 d −1 . The lower concentrations of O 2 and CH 4 as well as the higher concentration of CO 2 were observed in the WBS covers than those in the LCS covers. The highest CH 4 oxidation rates of the two types of soil covers both occurred in the bottom layer (20–30 cm). Compared to the LCS, the WBS showed higher CH 4 oxidation activity and methane monooxygenase activity over the course of the experiment. Overall, this study indicated the WBS worked well for the fluctuation of CH 4 influent flux during landfill stabilization.