氨氮在人工湿地–微生物燃料电池耦合系统中的数值模拟研究

Numerical Simulation of Ammonium Nitrogen in Constructed Wetland-Microbial Fuel Cell Coupled System

人工湿地–微生物燃料电池系统(CW-MFC)是将微生物燃料电池(MFC)与人工湿地(CW)耦合的一种新兴强化污水处理技术。随着研究的深入,焦点逐渐从CW-MFC产电、有机物的去除等转到了强化脱氮。在实体模型中,氨氮(NH+4-N)在开路系统中的去除率为57.6 ±1.45%,闭路系统中为67.6 ±4.74%。在此基础上开创性地借助Hydrus湿地模块建立了CW-MFC脱氮过程的数值模拟模型,以人工湿地模型为基础,构建水流运动及生化反应模型,并通过调整模型参数来拟合闭路耦合系统的强化脱氮效果,并取得了良好的仿真结果。基于模型预测结果,可通过采用单侧进水、双侧出水的方式来改善系统水流均一性问题。另外,可适当增加电极厚度以富集更多微生物,有利于提高电极的强化作用,进而提升系统的脱氮性能。实验数据与数值模拟手段的结合,有助于预测复杂耦合系统的脱氮效果,为系统设计的量化、工艺的优化、规模的放大化提供理论支撑和参考依据。

Constructed wetland-microbial fuel cell system (CW-MFC) is a novel wastewater treatment technology which integrates microbial fuel cell (MFC) into constructed wetland (CW). Recently, the focus of CW-MFC studies gradually shifted from electricity production and organic matter degradation to the enhancement of nitrogen removal. In the entity model, the removal percentage of ammonia nitrogen ((NH+4-N)) in the open-circuit system was 57.6 ±1.45%, and in the closed-circuit system was 67.6 ±4.74%. Combined with the experiment, we employed the Hydrus wetland module, to establish the numerical simulation model concerning CW-MFC nitrogen removal processes. This simulation included the water flow movement and biochemical reaction models which based on the module of CW. Through the adjustment of model parameters to fit the nitrogen removal effect in the closed-circuit coupled system, the sensitive simulation results were obtained. From the modeling results, it predicted that the uniformity of water flow could be improved by using one-sided inlet and two-sides outlet mode, and the enrichment of microorganisms by properly increasing the thickness of electrode would benefit the nitrogen removal. The combination of experimental data and numerical simulation methods could help predict the denitrification effect of the complex coupled systems, and provide theoretical support and reference for the quantification of system design, process optimization and scale expansion.