Abstract：
Aeration is an effective approach to sustainable landfilling but may lead to elevated temperatures within landfills, resulting in landfill fires or explosions. Therefore, aeration is usually combined with leachate recirculation to control the elevated temperatures within landfills. To predict landfill temperatures during aeration and recirculation, a local thermal non-equilibrium model is developed considering the heat generation of biodegradation, the heat removal due to evaporation and leachate-gas flow, and the effects of the capillary. The solver is implemented in OpenFOAM based on the finite volume method and validated against a waste-column experiment and an in-situ aeration test. The simulation results demonstrate that the assumption of local thermal equilibrium will distinctly overestimate the temperature, maximally by 15 °C in the studied case. The model is then used to simulate a typical aerobic landfill unit to investigate the formation of explosive gas mixtures and elevated temperatures under different operating conditions. The simulation results of gas composition suggest that aeration will not result in explosive gas within landfills. A reasonable recirculation method for temperature control with corresponding operating parameters under a group of values of aeration pressure (2000-4000 Pa) and recirculation rate (0.0001-0.0008 m/s) are proposed, which can provide some guides for the design of an aeration and recirculation combined system. For a given total volume of added leachate, a higher recirculation rate does not always mean better cooling, and the cooling effect of continuous recirculation is better than that of intermittent recirculation.
摘要：
曝气是可持续填埋的有效方法，但可能导致填埋场内的温度升高，导致垃圾填埋场火灾或爆炸。因此,曝气通常与渗滤液再循环相结合，以控制垃圾填埋场内的高温。为了预测曝气和再循环过程中的垃圾填埋场温度，建立了考虑生物降解产生热量的局部热非平衡模型，由于蒸发和渗滤液气流而去除热量，和毛细管的作用。求解器基于有限体积方法在OpenFOAM中实现，并针对废物柱实验和原位曝气测试进行了验证。模拟结果表明，局部热平衡的假设将明显高估温度，在所研究的案例中，最大可达15°C。然后将该模型用于模拟典型的好氧垃圾填埋场，以研究不同操作条件下爆炸性气体混合物的形成和升高的温度。气体成分的模拟结果表明，曝气不会导致垃圾填埋场内的爆炸性气体。提出了一种在曝气压力（2000-4000Pa）和再循环速率（0.0001-0.0008m/s）的一组值下具有相应操作参数的温度控制的合理再循环方法，这可以为曝气和再循环组合系统的设计提供一些指导。对于给定的总添加渗滤液体积，更高的再循环率并不总是意味着更好的冷却，连续循环的冷却效果优于间歇循环。
