Comparative Analysis of Biogas Estimation Models versus In-Situ Measurement in a Landfill Site in the State of Mexico, Mexico

This paper shows a comparative analysis of theoretical model for biogas estimations in landfill sites in order to determine reliability, accuracy and efficiency by comparing results with actual data obtained in-situ. The model from the Environmental Protection Agency (EPA) and the Mexican model were selected to estimate biogas generation in a landfill site located in the State of Mexico, Mexico with 36 wells. Both models are based on a first order equation for degradation of organic matter assuming that the biogas generation reaches its maximum after a period of time and then biogas generation decreases exponentially while the organic fraction of waste is consumed. Measurement in-situ, using a landfill gas analyser (GA5000), resulted in values of percentage concentration of landfill gas (CH4, CO2 and O2) with an average Frequency of 35.44 Hz (1/s) and emissions of methane of 3355.99 m3/hr in contrast with 4885.74 m3/hr from EPA model and 6780.56 m3/hr from Mexican model. The experiment evidenced significant variations in estimations versus actual measurements. Authors discuss the aspects and parameters that cause such variations in order to provide a comprehensive analysis which will help decision makers to base waste management strategies in Mexico on reliable data.