Zhang, Y.J.; Cheng, M.Y., and Zhao, Z.M., 2020. High performance of CWs with ferrous enhancement. In: Guido Aldana, P.A. and Kantamaneni, K. (eds.), Advances in Water Resources, Coastal Management, and Marine Science Technology. Journal of Coastal Research, Special Issue No. 104, pp. 882–886. Coconut Creek (Florida), ISSN 0749-0208.

Constructed wetland (CW) is a self-restoring and ecological treatment device and widely applied due to its ecological functions, high performance and low cost. CW can purify various types of wastewater. When CW is used to treat polluted surface water with a low C/N ratio, the treatment efficiency is limited by insufficient carbon sources and poor denitrification performance. Iron is widely available in nature and electrons can be released when ferrous ions are oxidized to ferric ions. It might be an effective attempt to use the released electrons in CW as an alternative of carbon sources to provide electrons for denitrification. In this study, ferrous ions were used in CW to treat polluted surface water with low C/N ratios (1 to 5) and achieve the significant denitrification performance. In influent with 15 mg/L TN and 75 mg/L COD, TN removal rate was increased by 16% after adding 10 mg/L ferrous ions in CW. Adding iron is an effective method for enhancing the denitrification performance of CW. The study provides a new idea for the application of CW in the future.