Removal of Fluoride and Arsenic by a Hybrid Constructed Wetland System.

Abstract

A pilot-scale hybrid wetland system was constructed for the removal of fluoride and arsenic from synthetic wastewater. After five months of operation, the fluoride and arsenic removal rate were at the value of 65 % and 90 %, respectively. Through calculation, the accumulation of fluoride in plants only accounted for 1.63 % of the accumulation in substrates, and the accumulation of arsenic in plants accounted for 3.3 % of that in substrates. Both the accumulation of fluoride and arsenic in plants were much higher in roots than that in leaves. And for substrates, the accumulation in the first layer was higher than the second layer. The changes of microbial community in the substrate of the wetland during the operation were also analyzed to investigate the effects of operating condition on the microbial community and to study the role of microorganism on the removal of fluoride and arsenic. The results showed that the relative abundance of Firmicutes reduced, while the relative abundance of Proteobacteria increased, indicating that the fluoride and arsenic in solution had a great influence on the microbial community. Findings of this study suggest that the hybrid constructed wetland system may be a promising process for the removal of fluoride and arsenic from synthetic wastewater.