Study On Electrokinetic Dewatering And Heavy Metal Remediation Technology Of Contaminated Sediment

Electrokinetic dewatering and heavy metal remediation technology can achieve the reduction and harmless treatment of low permeability and high water content contaminated sediment brought by environmental dredging,and is not subject to the permeability coefficient of the sediment,and has a high application prospect.However,the corrosion of electrode materials and excessive energy loss restrict the engineering application of this technology.Therefore,it is necessary to conduct further research on electrokinetic dewatering and heavy metal remediation technology with polluted sediment as the object.First,the electrode material research was conducted to evaluate the feasibility of several corrosion-resistant electrode materials for electrokinetic dewatering.The results show that the overall performance of conductive plastic composite electrode (EKG) is better than titanium-based metal oxide coated electrode,graphite electrode and titanium electrode,and it is the best test electrode.Secondly,explore the effects of electric field strength,board spacing and additives (polyacrylamide (PAM),citric acid) on the dewatering effect and energy consumption.The study found that electric field strength is positively correlated with dewatering effect and energy consumption;plate spacing is negatively correlated with dewatering effect and positively correlated with energy consumption;PAM has basically no effect on electrokinetic dewatering,citric acid will inhibit dewatering effect and significantly increase energy consumption.By fitting the relevant parameters of the dewatering process,an empirical model of dewatering is constructed.It was found that the relationship between water content and time conforms to the Gaussian (two-dimensional) function model;the dewatering rate and current are strongly linearly correlated under high electric field strength;the resistance and solids content show an exponential function model;It is an exponential function model;the instantaneous energy consumption per unit mass of water removal and solid content conform to the exponential function.Dewatering mass is related to the amount of charge transfer,dewatering energy consumption is linearly related to dewatering mass.By constructing the dewatering effect and energy consumption response model under the two variables of electric field intensity and plate spacing.It was found that in order to better improve the dewatering effect,time efficiency and reduce energy consumption,the electric field strength should be less than 10V/cmBy analyzing the properties of sediment and filtrate after dewatering.The results show that electrokinetic dewatering can cause changes in the properties of sediment and filtrate.The optimal removal rates of heavy metals Pb,Cu,and Zn at a 4cm board spacing of 20-50 V are 28%,51 %,and 35%,and the optimal voltage for heavy metal remediation it should not be higher than 10 V/cm.Finally,carry out engineering test research.It was found that using vacuum preloading combined with electric power technology,the electricity was energized for 4 days at 60 cm plate spacing and 1 V/cm electric field strength.The water content of the sediment is reduced from 70%-80% to about 50%-60%,and heavy metals in the sediment have a certain removal effect.