Comparison of Wastewater Treatment Performance for Two Typical Types of Constructed Wetland Considering Water Resource Conservation

The enrichment of groundwater and rivers by nutrients (nitrogen and phosphorus compounds) and their consequences is one of the most severe problems across the world. Transfer of nutrients from different sources into the environment causes eutrophication of surface waters, nitrate accumulation in groundwater, and others. Domestic wastewater is important nitrogenous and phosphorous source. Among the technologies for it, constructed wetland is emerging as a promising low-cost approach to improve treatment of point and diffuse sources in broad rural area in developing country. In this paper, the performance of two typical types of constructed wetlands, FWS (Free Water Surface) and SF (Subsurface Flow) constructed wetlands was investigated on pollutants removal, furthermore, the risk of resulting water bloom for the effluent is also discussed using the parameter of algae growth potential(AGP). The results showed that the pollutant removal rate measured in the wetland showed obvious seasonal change. But subsurface constructed wetland showed more preferable pollutants removal performance and higher stability for wastewater treatment than free water surface constructed wetland. The results also showed that SF wetland could alleviate the effluent’s potential of resulting in eutrophication.