Controlling Nitrogen Removalfrom Urban WastewaterinConstructedWetlands withNativeVegetationin Beijing

Excess nitrogen in urban wastewater effluent exacerbates eutrophication in water bodies, whereas nutrient-rich effluents can be reused for beneficial purposes, such as irrigation and agriculture. Therefore, controlling nitrogen removal is essential to meet water discharge quality standards and support sustainable water management, aligning with Sustainable Development Goal 6, which states to improve water quality, wastewater treatment, and safe reuse. This study investigates the control of nitrogen removal in urban wastewater using vertical flow constructed wetlands (VFCWs) with three native plants in Beijing: Phragmites communis, Typha orientalis, and Acorus calamus, pumice as substrates, and a COD/N ratio of 15/1. The objective is to identify the most suitable plant for producing effluent that meets key standards for water reuse. Synthetic influent was derived from a modified Hoagland solution. Water quality parameters, including dissolved oxygen, ammonium nitrogen concentration, nitrate nitrogen concentration, and total nitrogen, were continuously monitored over 17 days. Results showed that all three plant species significantly reduced the ammonium nitrogen concentration, with Typha orientalis performing the best. Due to the limited oxygen and short stabilization time, there is less nitrification and denitrification; therefore, the paper concludes that nitrogen removal is achieved through phytoremediation and pumice absorption. While the effluent quality met the criteria for reuse in urban landscaping, it did not meet the standard for discharge into the environment. The findings suggest that with improved system design, such as longer stabilization and added aeration, VFCWs could serve as a sustainable wastewater management solution.