Treatment of lignite-derived water by using horizontal subsurface flow constructed wetland

The lignite-derived water is created during the process of refining lignite.Fe,Mn,Phenol,NH3-N and TN are inevitably leached out from the lignite-derived water.In this research,a laboratory-scale horizontal subsurface flow constructed wetland was designed to treat the lignite-derived water.Five flow section hydraulic loading rates were used and the concentrations of Fe,Mn,Phenol,NH3-N and TN were detected by standard detection method.The results demonstrate that the system can achieve optimal removal efficiency with hydraulic loading rate(HRT)of 0.093m/d.With 0.093m/d HRT,the Fe,Mn,Phenol,NH3-N and TN removal efficiencies were up to 65.8%,78.2%,95.8%,88.0% and 92.3%,respectively,which can supply the surface water discharge limits and industrial cooling water standard requirements.Pollutant removal efficiencies showed dependence on seasons,and the highest removal efficiencies were appeared in August.The spatial distribution effects present that most of the pollutants were removed in the first half part of the wetland length and the existence of the reeds can improve the removal effect of the constructed wetland system.