Simulation and prediction of the effect of aeration, recirculation and degradation on landfill temperature in aerobic operation

Abstract

Much heat is released in aerobic landfills, which leads to temperature change. Quantitative prediction of temperature change with time and space is essential for the safe aerobic operation of landfill. In this article, based on the theory of porous media seepage mechanics and heat transfer, a seepage–temperature coupling model considering aeration, recirculation and degradation was established, which included internal energy change, heat conduction, convection and heat transfer. Moreover, combined with the long-time on-site monitoring temperature data from Wuhan Jinkou Landfill, the model’s reliability was preliminarily verified. Sensitivity analysis was carried out for aeration intensity, aeration temperature, recirculation intensity and recirculation temperature. Among the four factors, recirculation intensity influences the peak temperature most with a decrease of 20.11%. Compared with Borglin’s and Hao’s models, it is found that waste should not be assumed as a cell for temperature prediction. By comparing the results of Non-linear Ascent Stage model, Linear Ascent Stage model and Absent Ascent Stage model, it showed that the temperature difference of the three models decreases with the increase of operation time. In addition, the time point of peak temperature, t0, affects the temperature distribution. The above results provide a reference for predicting the spatial and temporal distribution of temperature and regulations for long-term aerobic landfill operations.