Removal of Various Contaminations from Drainage by Using Free Water Surface and Submerged Surface Flow Wetland Systems

This study demonstrates an efficient approach to remove various liquid-phase pollutants from wastewater by using constructed wetland (CW) systems. The plant used in this study was phragmites communis. Two types of CW systems, free water surface flow and submerged surface flow wetlands, are used to compare with their efficiencies for removing chemical oxygen demand (COD), Zn2+, true color, and NH3-N from the drainage. Experimental results confirmed that the CW treatment displays excellent capability for removing the pollutants, i.e., high removal efficiencies. This finding indicates that the growth of phragmites communis enables well-developed root network in CW system, thus leading to a higher adsorption capacity. The growth period of the root network in our case takes about 40 days, forming the bio-membrane. On the basis of the present work, the presence of bio-membrane on the plant root not only enhances but also stabilizes the efficiencies for removing various contaminations from the wastewater.