Enhanced Removal Of Rhodamine B(Dye) By Constructed Wetland Incorporating Microbial Fuel Cell

Constructed Wetland-Microbial Fuel cell technology(CW-MFC)is a combination of constructed wetland and microbial fuel cell technology,which can simultaneously achieve the sake of sewage treatment and energy output.This technology minimizes the damage to environment and reduces the energy consumption.Therefore,it is a valuable research direction for sustainable development and can helps to solve the increasingly serious environmental pollution problems.In this study,a lab-scale CW-MFC system with aluminum sludge as the wetland substrate was constructed to treat simulated wastewater containing rhodamine B,a common dye use extensively in industry.The system was continuously operated for monitoring the performance for 210 days(5 stages in total).During the trial,COD,nitrogen,phosphorus,dye concentration and DO were monitored and their changes at the cathode with power generation were closely measured to explore the influencing factors of the power output performance and pollutant treatment in the system.The main conclusions are as follows:1)The system achieved high removal efficiency of COD,the highest removal rate is: 89.98±1.88%;The rhodamine B dye removal efficiency was 88.25±5.95% in early period while it was stable about 40% at stage V.The dye removal mainly depends on the adsorption effect of wetland substrate(i.e.alum sludge),and the biodegradation maybe happened at the same time.2)With the condition of aeration in cathode layer,the ammonium nitrogen removal efficiency could achieve 77.97±21.88%,the total nitrogen removal efficiency could reached to 30.11±9.95% which was significantly higher than the condition of no aeration.The removal efficiency of total phosphorus was constantly remaining 97% constantly.This is due to the main reason as the removal is adsorption of aluminum sludge.This confirmed that the aluminum sludge can be an excellent wetland substrate for phosphorus removal.3)The system achieved good electricity output.The maximal voltage was 1141.8mV.The maximal current density was 1.83 mA/m~2.The highest power density was 6.17mW/m~2.The biggest coulombic efficiency was 0.127%,while the highest NER is 18.97kJ/kgCOD.The electricity production performance was influenced by COD concentration dye concentration and the DO concentration in the cathode.