微生物脱盐电池（Microbial Desalination Cell, MDC）是一种能够同时实现污水处理、水脱盐以及能量回收的新型水处理工艺。由于其不需外界能量的输入，近年来受到人们的广泛关注并得到了迅速发展。然而，以往MDC的装置规模普遍较小，其体积一般小于500 mL；且大多MDC均基于模拟污水开展研究，不利于其实用化应用推广。针对以上问题，本研究启动并运行了有效体积为10 L的堆叠式树脂填充型MDC中试装置。试验研究了采用模拟污水时不同运行条件对MDC性能的影响，考察了采用不同实际污水时MDC的产电特性和脱盐效果。此外，通过构建数学模型，对MDC的装置构型及最佳运行条件进行了预测，并通过试验得到了验证。当采用基于乙酸钠和葡萄糖的模拟污水时，MDC阳极对有机物的降解情况符合Monod模型，一个周期结束后两者COD的去除率均在75%以上。采用乙酸钠作为基质时MDC具有较好的性能，其平均电流、库伦效率、产电功率以及脱盐率均较高，分别达到了34.8 mA、7.7%、3.41 W/m3以及85.0%。提高初始盐水浓度和阳极COD、向阴阳极投加缓冲物质可以提高MDC产电，强化MDC脱盐速率与输出功率。当采用实际污水时，MDC在间歇式、连续流、零外阻连续流模式下均具有良好的污水处理效果，出水COD均满足《城镇污水处理厂污染物排放标准》(GB18918-2002)的一级A标准。在零外阻连续流下，MDC获得了最优脱盐效果，脱盐率达到了95%。进一步优化MDC构型，其实现了对污水中有机物、盐分以及总氮的同步去除，各项去除率均高于85%。基于MDC处理实际污水的试验数据，建立了MDC阳极基质降解速率、电流、脱盐速率的理论数学模型。以得到的数学模型对各项性能进行预测，并通过试验进行验证。验证结果表明，该模型对阳极出水COD、电流、脱盐速率预测相对误差分别为28%、13%、4.7%，模拟准确度较高。利用该模型预测MDC运行效果，结果表明：增大阳极进水COD和盐水初始浓度，降低阳极HRT，可以提高MDC的脱盐速率；试验装置膜对数为3-4对时，脱盐效果最高。该模型为进一步优化MDC构型与运行参数提了供理论依据。
Microbial desaliantion cell (MDC) is a newly developed water treatment technology integrating wastewater treatment, electricity generation and water desaliantion. MDC has drawn a wide attention since it needs no external energy input. However, the scale of traditional MDC reactors was commonly small, which was less than 500 mL. Most of MDC researches were based on synthetic wastewater, which did not fit for MDC practical application. To improve these problems, a 10-liter-scale stacked MDC packed with ion exchange resin was constructed and operated in this study. The influence of different operation conditions on MDC performance was analyzed when operated with synthetic wastewater, and the electricity generation and desalination performance of the MDC was investigated with real sewage. Besides, a mathematical model was formulated to optimize the MDC configuration and operation conditions, and validated with the experiment data.Substrate degradation in MDC anode chamber obeyed Monod Equation when the anolyte was synthetic wastewater with glucose and sodium acetate, and the COD removals in anode chamber were both higher than 75%. The MDC performed better when the anolyte substrate was sodium acetate, with the average current of 34.8 mA, coulombic efficiency of 7.7%, power density of 3.41W/m3 and desalination efficiency of 85%. Increasing initial salt concentration and anode COD, and dosing phosphate buffer solution into the anolyte and catholyte could enhance the desalination rate and and power output of MDC.When the MDC was operated in batch, continuous, and non-external resistance mode driven by real sewage, the effluent COD met the grade A standard regulated in GB18918-2002 of China. The maximum desalination efficiency reached 95% when the MDC was operated in non-external resistance mode. Further optimized the MDC configuration realized removing organics, salt and TN simultaneously, and the removal rates were all higher than 85%.A mathematical model integrating anode substrate degradation rate, current generation rate and desalination rate was formulated based on the MDC experiment data driven by real sewage. The MDC performance was predicted and validated with the experiment data. The validated results showed that the model was fitted with the experiment data well, with the relative error on anode effluent COD of 28%, current of 13%, and desalination efficiency of 4.7%. The predicted results showed that increasing anode COD and initial salt concentration, and decreasing anode HRT could enhance the MDC desalination rate, and the optimal number of membrane pairs in this study was 3-4. The model provided a theoretical base o further optimize MDC configuration and operation conditions.
