Simultaneous Remediation Of Eutrophication Water And Sediment By Ecological Floating Bed-SMFC Coupling Device

With the development of industry and the growth of population,a large number of industrial and agricultural pollutants enter into the water body by waste water discharge,atmospheric sedimentation,rainwater leaching and so on.The continue gathering of pollutants result in the deterioration of water quality.A considerable part of the pollutants will accumulate in the sediment and cause the pollution of sediment.At the same time,pollutants will transfer and transform between the water body and the sediment.When the external pollution is effectively controlled,the release of pollutants from the sediment to the overlying water becomes the main reason for the eutrophication of the water body.Because of the ability of electric generation and pollutants degradation,microbial fuel cell(MFC)has become a research hotspot in the field of pollutant remove and environmental remediation.An ecological floating bed-sediment microbial fuel cell coupling system was constructed in our study.The effects of plants,electrode materials,graphene modification,electrode distance and electrode area on the power generation and eutrophication water with sediment remediation of the coupling device were studied.The remediation effect of sediment microbial fuel cell,ecological floating bed and coupling device were compared.The main results are as follows:(1)Floating bed plants,anode materials and graphene modified coupling device were compared in terms of the effect of various factors: floating bed plants >graphene modified > anode materials,Calamus was better than Canna,carbon felt was better than graphite plate,graphene modified was better than non-graphene modified.(2)The results show that the larger the electrode area is,the higher the output voltage of the coupling device is.Properly increasing the anode electrode area is helpful to improve the battery voltage,but when the anode electrode area is too large,the power density decreases.There is an asymmetric linear relationship between the effect of electricity generation and electrode area,which may be related to the increase of electrode resistance.(3)Coupling devices with different electrode spacing are compared.Electrode spacing is an important factor affecting the performance of coupling device.The reduction of electrode spacing can effectively reduce the internal resistance,facilitate the flow and mass transfer of substrates and products,improve the output power,and change the electrode spacing will change the dissolved oxygen in the solution around the anode microorganism of the battery,thus affecting the activity of the anode microorganism of the battery,and ultimately affect the operation of the battery.When the electrode distance of coupling device is 60 cm,the device still has a good effect of pollutant removal and electricity generation.(4)Compared with the ecological floating bed,SMFC and coupling device improved the effect of water restoration.Plants are helpful to the removal of nitrogen,phosphorus and organic matter in overlying water,but have little effect on the removal of pollutants in sediment.The coupling system composed of ecological floating bed and sediment microbial fuel cell has achieved the best effect of overlying water and sediment remediation.The removal rates of COD,TN and TP in the overlying water were 96.3%,91.8% and 81.2% respectively,the removal rates of organic matter and TN in the sediment were 17.4% and 87.1% respectively,and the fixation rate of TP in the sediment was 26.9%.