Macrophytes have the potential to withstand pollutant-induced stress and can be used to clean contaminated water using phyto-extraction, phyto-degradation, phyto-filtration, phyto-stimulation, and phyto-volatilization technique(s). Phytoremediation through constructed wetlands (CWs) for eliminating inorganic and organic pollutants from household sewage and wastewater has attracted scientific attention. CWs are artificially engineered treatment systems that utilize natural cycles or processes involving soils, wetland vegetation, and plant and soil-associated microbial assemblages to remediate contaminated water and improve its quality. Herein, we present a detailed assessment of contaminant removal effectiveness in different CW systems, i.e., free-water surface or surface-flow constructed wetlands (FWSCWs/SFCWs), subsurface-flow constructed wetlands (SSFCWs), and hybrid constructed wetlands (HCWs). Several wetland floral species have been reported as potential phytoremediators, effectively reducing aquatic contamination through biodegrading, biotransforming, and bioaccumulating contaminants. Water hyacinth (Pontederia crassipes) is one of the most resistant macrophytes, capable of tolerating high nitrate (NO₃⁻) and phosphate (PO₄²⁻) concentrations. Other aquatic weeds also effectively alleviate biological oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), and pathogen levels and ameliorate the impact of different ionic forms of nitrogen (N), phosphorus (P), and trace elements (TEs). The review primarily focuses on using hydrophyte(s)-microbe(s) associations in different CWs as an essential phytoremediation tool for sustainable management of freshwater ecosystems, ecorestoration, and prospective resource recovery, favoring a circular bioeconomy (CBE).

The removal of contaminants from sewage wastewater through constructed wetlands is becoming increasingly popular worldwide. Constructed wetland (CW) is a man-made structure for wastewater treatment that uses natural processes associated with wetland vegetation, soils, and their associated microbial combinations. This study investigated the performance of experimental vertical flow constructed wetland (VFCW) cells to remove heavy metals (HMs) from primary treated sewage. The primary treated sewage was collected from the sewage treatment plant (STP) in the campus of Indira Gandhi National Tribal University, Amarkantak, India. Sewage wastewater samples were collected from all cells of the experimental VFCW and analyzed for four heavy metals (Zn, Fe, Cu, and Cr). The plant species results show that the removal efficiency of the Canna indica L. for Zn, Fe, Cu, and Cr was 95%, 92%, 96%, and 93 % and Acorus calamus L.were 89 %, 80 %, 91 %, and 47 % respectively. These macrophytes with the substrate (gravel and sand) have presented a wide range of tolerance to all the selected metals and therefore can be used for field-scale constructed wetland removal of heavy metals from sewage wastewater.