Construction Of Upflow Stacked Microbial Desalination Cell (USMDC) And Optimizatioin Of Operation Parameters

The recycling of tail water is an important way to solve the problem of water shortage.For the current large-scale use of low-end reuse water,the main purpose of treatment is to reduce salt and effectively scale.Although the existing desalination technology can fully desalinate industrial wastewater,its desalination effect is far beyond the use standard of low-end reuse water.In addition,a large amount of external energy input is required in the operation process,which will cause a large amount of energy waste.Microbial desalination cell（MDC）has become a new desalination technology solution,because this technology doesn’t need external energy input.However,the existing MDC reactors have the problems of low desalination efficiency and poor stability,especially in long-term operation.Therefore,by coupling the Upflow Microbial Desalination Cell（UMDC）and Stacked Microbial Desalination Cell（SMDC）we can build the Upflow Stacked Microbial Desalination Cell（USMDC）,and its performance is characterized Optimization.The experimental results show that the maximum desalination rate of USMDC can reach1.04 g·（L·h）^-1,which is higher than 0.38 g·（L·h）^–1 and 0.71 g·（L·h）^–1of UMDC and SMDC under the same conditions,and the desalination rate of USMDC is 2.7 times and 1.5 times of UMDC and sdmc respectively.In addition,the maximum range of desalination rate of USMDC is 4.5%,and the maximum range of UMDC and SMDC is 8.4%and 16.5%.Compared with other reactors,USMDC has better stability.Due to the increase of ohmic impedance caused by the increase of desalting chamber numbers,the power generation capacity of USMDC is slightly lower than that of UMDC,but in the long-term operation process,the power generation stability of USMDC is higher than that of UMDC and SMDC.Therefore the power generation performance of USMDC is still better.In addition,the electron transfer efficiency of three kinds of MDC was compared,which proves that USMDC has successfully improved the electron transfer efficiency of the UMDC and SMDC.Based on the successful construction of the USMDC,this paper also explores the best operating conditions of USMDC in actual operation,and improves the desalination and power generation performance of USMDC by optimizing parameters such as anode material type,influent salt concentration,anode liquid type and COD concentration,Pt load in air cathode,etc.The results show that the operation effect of USMDC is the best when the external resistance is 5Ω,the anode material is carbon felt,the number of desalination chamber is 2,the carbon source of anode liquid is sodium acetate,the COD of influent water is 738 mg/L,the p H of influent anode liquid is 8.5,and the salinity of influent water is 35 g/L.This study provides an optimized solution of MDC technoligy,and provides a basis for further industrial application of MDC.