Constructed Wetlands: Insights and Future Directions in Sustainable Approach for Wastewater Treatment

In recent years, the presence of contaminants of emerging concern (CECs) has raised serious concerns as they pose significant threats to water quality, aquatic ecosystems, and human health. To address this issue, various treatment technologies have been employed to remove CECs from wastewater. Among these technologies, constructed wetlands have gained popularity as an effective and sustainable approach for remediation. Constructed wetlands (CWs), an engineered system designed employing combination of wetland soils, plants, and associated microbial communities emerged as vital tools for treating different types of wastewater including domestic, mining, industrial, and agricultural effluents. In CWs, selection of plant, microbial media, Hydraulic Retention Time (HRT), and Hydraulic Loading Rate (HLR) play crucial roles in the removal of CECs through mechanisms such as filtration, sedimentation, adsorption, volatilization, microbial activity, and phyto-accumulation along with phytoremediation. Wetlands are categorized into sub-surface flow and free water surface types, with the aim of optimizing the elimination of organic pollutants from wastewater. Constructed wetlands exhibit superior performance in removing organic nutrients, heavy metals, pharmaceuticals, and personal care products. Notably, these systems demonstrate higher efficiency when operating under low hydraulic loading rates (HLR). This chapter provides a comprehensive overview of constructed wetlands and their significance in phytoremediation, factors affecting the system’s removal efficiency, and highlights the potential of this eco-friendly approach for environmental remediation. It serves as a valuable resource for researchers, professionals, and decision-makers, offering information on the current state of the art and potential future directions for effective and sustainable pollution control.