OPERATING PARAMETERS OPTIMAL SCHEME AND FEASIBILITY RESEARCH OF ENHANCING STRATEGIES FOR ELECTRO-KINETIC REMEDIATION ON LEAD-POLLUTED ESTUARY SEDIMENTS TREATMENT

The accumulation of lead (Pb) in sediments resulted from substandard discharge of industrial and agricultural sewage hold serious threat to agro-ecology and human health during its recycling process. Electro-kinetic remediation (EKR) is a promising technique for Pb decontamination in porous matrix while pH polarization remains to be the main obstacle for its widespread application. In this study, lab scale EKR experiments were conducted with enhanced strategies of non-uniform electric intensity (NEI), polarity reversal (PR) and electrolyte conditioning (EC). From the obtained results, all the strategies could alleviate the pH polarization of sediments and increase the removal of Pb by 6.2-37.4 A. Operating parameters of electric intensity (EI), electrode exchange frequency and electrolyte type were optimized and determined to be 1.0 V/cm. 24 hitime and 0.1 M HAc, respectively. Higher extraction efficiencies of Pb (75-86%) were reached when employed the enhanced EKR and the optimal result was observed when applied the NEI, PR and EC strategies simultaneously. The remediation duration, energy utilization efficiency and energy cost of EKR with optimal enhanced scheme to remove all sediment Pb was evaluated to be in an acceptable value of 178.2 h, 42.3 mg/kWh and $ 0.65/kg, respectively. The methodology and results in this study might provide theoretical foundation to support the designation of EKR in full-scale applications.

Automated summary

This study conducted lab scale EKR experiments with enhanced strategies of non-uniform electric intensity, polarity reversal, and electrolyte conditioning to alleviate pH polarization of sediments and increase Pb removal. Optimized operating parameters resulted in higher extraction efficiencies of Pb, especially when using enhanced EKR strategies simultaneously. The remediation duration, energy utilization efficiency, and energy cost of EKR with optimal enhanced scheme to remove all sediment Pb were acceptable for full-scale applications.