ELECTROREMEDIATION OF ZN(II) CONTAMINATED SOFT BANGKOK CLAY WITH CATHODE DEPOLARIZATION TECHNIQUE

4 ABSTRACT: Four electrokinetic experiments were performed to examine the application of electrokinetic remediation to remove heavy metals from the soft Bangkok clay. The experiments were carried out by applying a direct-current electric field of 20 V through the soil loaded with Zn(II) at the level of 1,000 mg per kg for 3 and 7 days. In addition, the cathode depolarization technique, in which hydroxide ions generated from electrolysis reactions are eliminated by flushing acidic solution into a cathode reservoir, was introduced to improve the efficiency of electrokinetic remediation. The experiment results showed that only electrokinetic remediation was able to remove 82 percent of the contaminants in a period of one week. During this period, the combination of electrokineti c remediation with the cathode depolarization technique has raised the removal efficiency after 7 days of the treatment by 15 percent while the energy expenditure was slightly increased from 273 kWh per m 3 to 301 kWh per m 3 . Therefore, the application of electrokinetic remediation with the cathode depolarization technique can be considered as an efficient ground remediation method for the soft Bangkok clay.