Macrophytes for Utilization in Constructed Wetland as Efficient Species for Phytoremediation of Emerging Contaminants from Wastewater

Emerging contaminants (EC) are the modern age chemicals that are new to the environment. It includes pharmaceuticals & personal care products (PPCPs), pesticides, hormones, artificial sweeteners, industrial chemicals, microplastics, newly discovered microbes and many other manmade chemicals. These chemicals are harmful and having negative impacts on human being and other life forms. Existing treatment systems are ineffective in treating the EC and the treated effluent act as source of pollution to the water bodies. Considering the requirement of new technologies that can remove EC, the Constructed wetlands (CWs) are getting popular and can be a valid option for the treatment of EC. In this context application of macrophytes in CW have increased the removal performance of constructed wetland system. Growing macrophytes in CW have augmented the removal of EC from these systems. In different studies macrophytes supported the removal process of EC in CW and a removal efficiency up to 97% was achieved. This review summarizes the direct and indirect roles of macrophytes in CW in the treatment of EC. Also, it evaluates the success of CW technology, in treating EC, its limitation, and future perspective. The direct role of macrophytes include precipitation on root surface, absorption, and degradation of EC by these plants. Growth of macrophytes in CWs facilitates the uptake EC by the absorption and detoxify them in their cell with the help of enzymatic and hormonal activity which supports the removal of EC in wetland system. Indirect impacts, which appear to be more significant than direct effects, include increased removal of EC through better rhizospheric microbial activity and exudate secretions, which enhances the removal by four times. Thus, this review emphasizes combined application of CW and aquatic macrophytes which augmented the performance of CW for the treatment of EC.