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Numerical investigation of hydrogen sulfide transfer in unsaturated amended-soil considering chemical reaction process

Hydrogen sulfide is an odorous gas that has been produced during the biodegradation process of municipal solid waste in landfill, and it causes potential serious problems to the surrounding environment due to its toxic, flammable and odorous properties. In solving this problem, removal of hydrogen sulfide by adding soil amendment in landfill cover has been considered as one of the effective and novel solutions. Adsorption and chemical reaction are two main mechanisms of hydrogen sulfide removal in amended soil. Hydrogen sulfide is on one hand a weak acid that can react with alkaline substance in soil in the presence of pore water, one the other hand, it is a reductant that can be oxidized by soil minerals. So far, however, the influence of soil chemical reaction on the hydrogen sulfide removal has not been fully understood.

The objective of this study is to investigate the transfer of hydrogen sulfide in unsaturated soil considering the chemical reaction process. A series of numerical simulations considering parameters like water content, type and dosage of amendment will be carried out using finite element method. Interactions between soil particles, pore fluid and gas phase will be studied. Particularly, the time dependent chemical reaction processes, which include oxidization and acid-alkali reaction, will be incorporated.

Author(s):

Mengyao Xie    
Hong Kong University of Science and Technology
Hong Kong

Charles Wang Wai Ng    
Hong Kong University of Science and Technology
Hong Kong