Modeling on gas generation process of closed municipal solid waste landfill

A closed municipal solid waste landfill can generate tremendous quantities of gas and leachate during its decomposition process. It is important to estimate the quantity of landfill gas generation for designing landfill gas collection and control system. In this paper, the model to estimate the gas generation in the landfill is deeply studied. Half-value time of gas generation is defined as a new concept to point out the deficiency of the conventional gas generation model, namely the exponent model. Based on some energy dissipating postulates, we deduce the differential governing equation of the gas generation process, and establish a new 3-parameter model for this, process. The new model can overcome the deficiency of the exponent model. Mathematical proof shows that the exponent model is one special expression of the new derived model. The comparisons between the new model simulation and measured field data are conducted, and good agreements have been found. The new 3-parameter model in this paper may be helpful to the design, management and reutilization of corresponding municipal solid waste landfills.