An attempt to electrically enhance phytoremediation of arsenic contaminated water

Water polluted with arsenic presents a challenge for remediation. A combination of phyto- and electro-remediation was attempted in this study. Four tanks were setup in order to assess the arsenic removal ability of the two methods separately and in combination. Lemna minor was chosen for As remediation and collected from a ditch in Utrecht, The Netherlands. The tanks were filled with surface water without any pre-cleaning, therefore containing various elements including metals as Mn (2.9 mg L(-1)), Cu (0.05 mg L(-1)), Fe (1.39 mg L(-1)), and Ba (0.13 mg L(-1)). This water was then spiked with As and allocated to a feed container, guaranteeing a continuous flow of 0.12 mL s(-1) to each tank. Two experiments were performed: Exp. 1 with 3 consecutive stages with rising applied voltage and Exp. 2, with a constant voltage over a period of 6 d. Measurements of pH and temperature were taken every working day, as well as water samples from outlets of all tanks including feed container for control. From the present study, there was no evidence that As had been taken up by the plants, but a strong depletion of As was observed in the tanks where current was applied. Preliminary results clearly showed that applying voltage to the electrodes caused 90% removal of As from the spiked surface water.