Research On Heavy Metal Wastewater Treatment With Constructed Wetlands

As the environmental damage of heavy metals wastewater, the treatment on heavy metals wastewater gained much more attention day by day. In order to offer some valuable reference for practice project design and technique control for a constructed wetlands, in this research, a constructed wetlands was used to study the influence of the structure and the fun conditions on the wastewater containing copper, zinc and lead treatment. And the distribution of residence time and flow form of the wetland system was studied as well.First, the removal efficiency of heavy metals of the six systems constructed with sterilized coke only, sterilized gravel only, domesticated coke only, domesticated gravel only, coke filler with reed and gravel with reed was compared. The result shows that the heavy metal removals of the systems with coke filler only are better than that of the systems with gravel filler only; and that of the systems with reed are better than that of the systems without. After reeds planned in systems with gravel filler, the heavy metal removal efficiency of them were little worse than that of reed bed with coke filler.The analyze of the influence of the factors on the function of the wetlands shows that wetlands have a steady and effective removal on heavy metals, such as copper, zinc and lead, in wide ranges of the initial conditions. In the conditions of pH=3.5-6.7; HRT=10h; 6.76-15.2mgCu²⁺/L of the copper treating system, pH=3.6-6.8; HRT=10h; 12.2-16.2mgZn²⁺/L of the zinc treating system, pH=3.3-3.9; HRT=10h; 23.8-38.4mgPb²⁺/L of the lead treating system, the systems had more than 95% removal efficiencies of the three metals individual.More than 98% of the three metals remained in the system was in the filler. About 1% of all the copper remained in the system was absorbed direct by the reed. However, analyze compared with the systems without reed shows that 30% of all the copper in the reed bed was immobilized by the indirect effect of the reed (The gravel filler systems).The result of the dipping and flushing experiment on the substrate treated by...