Innovative Approaches for Performance Enhancement of Constructed Wetlands

Despite the availability of numerous efficient conventional wastewater treatment technologies, over 80 percent of all wastewater produced is discharged into aquatic bodies worldwide without adequate treatment. Traditional wastewater treatment methods are expensive, technologically complex, and energy-intensive; thus, it becomes imperative to explore nature-based solutions that are sustainable and economical. Constructed wetlands (CWs) are ecologically engineered and self-adaptive wastewater treatment and management systems designed to employ the processes taking place in a natural wetland with a greater degree of control. Microbes play a key role in transforming and mineralizing pollutants in CW. Nitrosomonas, Nitrosospira, Proteobacteria, Actinobacteria, Firmicutes, Chloroflexi, and Bacteroidetes are some of the commonly reported species in wetland systems. Microbes metabolize nutrients and organic pollutants through various processes like nitrification, denitrification, sulfate reduction, and methanogenesis. Bioaugmentation and the incorporation of various other innovative approaches to improve the efficiency and long-term performance of constructed wetlands has received a lot of attention lately. The present work attempts to review the role of microbes in CWs and the influence of microbial augmentation on the performance enhancement of wetland systems. Additionally, the influence of selecting appropriate components (substrate and plants) for the wetland system; optimizing crucial design elements (wetland configuration, loading rate, retention time, flow pattern), and adopting other innovative approaches (like vermifiltration, effluent recirculation, aeration, and integration of microbial fuel cell) on the treatment of constructed wetland system is also reviewed. The stability, sustainability, and implementation of constructed wetland systems can be significantly enhanced by incorporating performance enhancement approaches.