PURIFICATION EXPERIMENT OF THE WASTE WATER USING PLANTS ABSORBING HEAVY METALS

In this paper reports the results of purification experiment of the leachate from the tunnel rock muck including selenium, and purification experiment of the river water including arsenic, using plants which absorbing heavy metals named Eleocharis acicularis. In the leachate experiment, we measured the time course in 90 days of selenium concentration of the leachate and the selenium content of the E. acicularis which were floated interior water storage tank on-site. In the river water experiment, we poured the river water 300 L in two days to the artificial channel which was laid with E. acicularis mats to measure the change of the arsenic concentration of the river water and the arsenic content of the E. acicularis. As the results of water storage tank experiment, reduction of serenium concentrations of the leachate were confirmed from 0.039 mg/L to 0.002 mg/L during 90 days. And we also confirmed the reduction of the arsenic concentrations of the leachate and E. acicularis in the artificial channel experiment. The arsenic concentration of river water decreased to approximately 60% of initial value, the arsenic content changed to 4.16 mg/kg after a 200 L was flow down. In addition, the amount of sample water was reduced to 41 - 64 % of initial value through evapotranspiration from the plants and the artificial channel.