Performance of the Tidal-Flow Wetland for Wastewater Treatment in Low Temperature Seasons

The tidal-flow constructed wetland is a new type of constructed wetland proposed by the University of Birmingham, U.K. The principal of the wetland takes advantage of the rhythmical movement of wastewater and air which accelerates the alternation of aerobic and anaerobic to realize and enhance pollutant removal. This study focused on two aspects, the different operation performances for treating pollutants at a low temperature in winter between tidal-flow and traditional continuous-flow constructed wetlands, and the influences of treatment efficiency under different operating circumstances. The results showed that, under 0.2m³/m²/dhydraulic load, the removal rates of the three-cycles/d tidal flow constructed wetland for NH₄⁺-N, COD and PO₄^3--P could reach 48.57%, 68.96% and 29.02% respectively, which were about 30%, 20% and 20% higher than these in continuous flow wetlands, correspondingly.