Nature and Characteristics of Emerging Contaminants as a Triggering Factor for Selection of Different Configurations and Combinations of Constructed Wetlands: A Review

The presence of emerging contaminants (ECs) in the environment, especially in the water and wastewater matrices, has become a major headache for the competent authorities, because even with the mildest of exposure aquatic organisms, as well as humans, can exhibit chronic/acute toxicity. In the last few years constructed wetlands (CWs) have become a popular method to eradicate ECs from water and wastewater, because they are an environmentally benevolent, economically feasible, and aquatic plant-based natural technology. However, information is not readily available on how to configure a CW (or combination of CWs, for hybrid CWs) to ensure the substantial removal of ECs. Thus, the present review analyzes how the various physicochemical properties of ECs govern their major removal pathways in different CWs and how the design configuration of a CW can lead to better EC removal. Finally, some recommendations regarding the possible configuration or combination of CWs on the basis of the ECs’ known physicochemical properties are made. This review article will help in selecting the proper combinations of CWs to eliminate the ECs of concern (known or unknown) from the aquatic matrices.