Study on the Purification Efficiency of Micro-polluted River Treated by Subsurface Horizontal Flow Constructed Wetlands

In the field conditions, the studies about subsurface horizontal flow constructed wetlands (SHFCWs) treating micro-polluted river were carried out to learn the purification efficiency and influences of temperature. Changes of pH, DO and ORP were studied, and analyses for removal efficiency of pollutants affected by temperature were presented. DO and pH varied from influent to effluent. Removal rates of NH4+-N (ammonia), TN-N (total nitrogen) and COD (chemical oxygen demand) were increased with the raising temperature, which could be reached to 90%, 50% and 20%. Removal rates of TP-P (total phosphorus) varied from 30% to 60% in planted wetlands. Test results showed removal rates of NH4+-N and TN-N were strongly correlated with temperature. Due to low concentration of influent, the correlation between COD and temperature was poor. Because PP-P (particulate phosphorus) was the main form in phosphorus removal, there was almost no relationship between TP-P and temperature. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Conference ESIAT2011 Organization Committee.