Gas permeability and emission in unsaturated vegetated landfill cover with biochar addition

作     者：Junjun Ni Jingsong Zhou Yuchen Wang Haowen Guo 

作者机构：School of TransportationSoutheast UniversityNanjingChina Department of Civil and Environmental EngineeringThe Hong Kong University of Science and TechnologyHong Kong SARChina 

出 版 物：《Biochar》 (生物炭（英文）)

年 卷 期：2023年第5卷第1期

页      面：815-829页

核心收录：

学科分类：0831[工学-生物医学工程（可授工学、理学、医学学位）] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 0818[工学-地质资源与地质工程] 09[农学] 0903[农学-农业资源与环境] 0706[理学-大气科学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0901[农学-作物学] 090301[农学-土壤学] 

基　　金：Fundamental Research Funds for the Central Universities(Grant No.3221002220A1) State Key Laboratory of Subtropical Building Science in South China University of Technology(Grant No.2022ZC01) 

主　　题：Plant-biochar interaction Gas permeability model Gas emission Numerical simulation 

摘      要：Plant-biochar interaction has been recognized to affect the hydraulic properties of landfill cover soils,while its influence on landfill gas emission is rarely *** study investigated the coupled effects of biochar and vegetation on gas permeability and emission in unsaturated landfill cover through an integrated theoretical modelling and laboratory ***,a gas permeability model was developed for vegetated coarse-grained soils with biochar ***,a well-instrumented laboratory column test and two tests from the literature,considering bare,grass,biochar and grass+biochar conditions,were used for model ***,a numerical parametric study was conducted to investigate the influence of root growth and drought conditions on the gas emission *** showed that the developed model can satisfactorily capture the gas permeability of unsaturated soils at various degrees of *** lowest water retention capacity,the highest gas permeability and gas emission rate after 24 months of growth were observed in the grassed ***,adding biochar in vegetated soils can maximize the water retention capacity and decrease the gas permeability,resulting in the lowest gas emission *** measured gas emission rates for the four cases meet the recommended value by the design *** parametric study showed that the increased root depth from 0.2 m to 0.4 m improved the gas emission rate by 170%in the grass case but decreased by 97%in the grass+biochar *** the severe drought condition with soil suction around 500 kPa,the gas emission rate in the grassed case exceeded the design value by 18%,while those in the biochar cases were far below the allowable ***,peanut shell biochar should be considered to amend the grassed landfill cover using coarse-grained soils as it can significantly improve engineering performance in reducing gas emissions under extreme drought conditions.