Treatment of Wastewater with Different Ratios of Carbon to Nitrogen Using an Enhanced Nitrogen Removal System of Constructed Wetland

Abstract

An enhanced nitrogen removal system of constructed wetland has been established, and for which kind of nitrogen containing wastewater was suitable to be treated by such enhanced system was also investigated. The results show that when co-controlled by intermittent aeration and carbon source addition, dissolved oxygen concentration and process carbon-nitrogen ratio in enhanced system were improved, meanwhile TN removal capability was enhanced. For wastewater that contains low concentration of carbon and nitrogen, or low concentration of carbon but high concentration of nitrogen, or high concentration of carbon and nitrogen, or high concentration of carbon and low concentration of nitrogen, the average removal efficiency of COD, TN, NH4+-N, NO3--N and TP in enhanced system were 68.1%, 78.2%, 70.8%, 86.7% and 71.2%, of which the purification capability was significantly better than that of the control system. The enhanced system is especially suitable for treatment of wastewater that contains low concentration of carbon and high nitrogen.