The lead contaminated land treated by the circulation-enhanced electrokinetics and phytoremediation in field scale.

Some agricultural lands have been contaminated by heavy metals in Taiwan for several decades, because the irrigation system was polluted by wastewater. In this study, a circulation-enhanced electrokinetics (CEEK) and phytoremediation were applied alternately to the real lead-contaminated site. In the beginning, the CEEK was used; then, the corn plants were raised. After this phytoremediation, the CEEK was employed again. Experimental results show that the lead concentration can be reduced from 5672 mg/kg to 2083 mg/kg (around 63%) after the three-stage treatment (CEEK + corn + CEEK). At each stage, CEEK, corn plants, and CEEK can remove around 25%, 5%, and 30% lead from the soil, respectively. During the whole process, the soil pH can maintain around neutral range and the electrical conductivity of soil was stable. The electricity consumption of the CEEK was quite low (89 USD per ton) and the corn plants still were alive throughout the remediation.