Evaluation and statistical optimization of methane oxidation using rice husk amended dumpsite soil as biocover

摘要

A laboratory scale study was conducted to investigate the effect of rice husk amended biocover to mitigate the CH_4 emission from landfills. Various physico-chemical and environmental variables like proportion of amended biocover material (rice husk), temperature, moisture content, CH_4 concentration, CO_2 concentration, O_2 concentration and incubation time were considered in the study which affect the CH_4 bio-oxidation. For the present study, sequential statistical approach with Placket Burman Design (PBD) was used to identify significant variables, having influential role on CH_4 bio-oxidation, from all variables. Further, interactive effect of four selected variables including rice husk proportion, temperature, CH_4 concentration and incubation time was studied with Box-Behnken Design (BBD) adopting Response Surface Methodology (RSM) to optimize the conditions for CH_4 oxidation. In this study, the maximum CH_4 oxidation potential of 76.83 μgCH_4 g_(dw)~(-1) h~(-1) was observed under optimum conditions with rice husk amendment of 6% (w/w), 5 h incubation time at 40 ℃ temperature with 40% (v/v) initial CH_4 concentration. The results for CH_4 oxidation potential also advocated the suitability of rice husk amendment in biocover system to curb emitted CH_4 from landfills/open dumpsite over conventional clay or sand cover on supplying CH_4 and O_2 to microbes on maintaining proper aeration.