Application Study Of Sediment Microbial Fuel Cell In The Remediation Of Contaminated Sediment

With the rapid development of urbanization and industrialization in China,untreated sewage and wastewater are discharged into rivers and lakes,causing black odor phenomenon of water bodies.As an important part of the water ecosystem,the substrate has a continuous material exchange with the overlying water and becomes an enrichment site for various pollutants.In order to prevent secondary pollution and eradicate the phenomenon of black odor in water bodies,it is necessary to start from substrate management.Sediment Microbial Fuel Cell(SMFC)is a new bioremediation technology,which can decompose organic matter in sediment and generate electricity.The technology has great prospects for application in sediment remediation and water quality purification.Different SMFC devices with different materials and configurations were constructed.The removal efficiency of pollutants and electricity production performance were studied in order to optimize the devices,which are efficient and cost-effective and easy to apply in the field.And the SMFC device was applied for in-situ sediment remediation of rivers.The main contents and conclusions are as follows.(1)Two SMFC systems with the specifications of 100×70×70cm were constructed by using a honeycomb structure wrapped with carbon fiber cloth for the anode and graphite felt for the cathode.After two months,the SMFC device had obvious degradation effect on total organic carbon(TOC)in the sediment.when the overlying water has the flow velocity,TOC was decreased by 19.54% and the fixation of phosphate was realized.Chemical oxygen demand(COD)in the overlying water was decreased by 38%.The results show that SMFC can promote in situ remediation of aquaculture water bodies and help reduce the treatment cost of aquaculture pollution.(2)In order to improve the pollutant removal efficiency,several groups of SMFC systems with different electrode materials and structures were constructed to compare pollutant removal efficiency and the power production performance.It was concluded that the SMFC system with carbon fiber brushes and graphite felt electrodes showed better power production performance.After two months,TOC in the sediment of the SMFC system with graphite felt electrodes decreased by 19.73% at an external resistance of 100 Ω.The concentrations of COD,ammonia nitrogen,total nitrogen(TN)and total phosphorus(TP)in the overlying water decreased by 61%,38%,72% and73%,respectively.At the same time,SMFC significantly inhibited the eutrophication of water body and the rapid growth of algae.(3)Based on the experiments in the laboratory,in-situ sediment remediation project in the estuary of Xinyong River was carried out with a honeycomb-lattice structure of hot-pressed carbon powder as the anode and graphite felt as the cathode.In the process of field construction and installation,the molds for anode fixation and down-pressing were designed and a systemic installation method was summarized,which improved the installation efficiency and quality of SMFC device.After three months,total organic matter and TN in the sediment decreased by 30.67% and 22.52%,respectively.The SMFC device also changed the diversity of microbial community structure near the anode,which has an important engineering application value.