Occurrence, fate and distribution of emerging organic pollutants in full-scale hybrid constructed wetlands treating municipal effluents

Abstract

The presence of emerging organic pollutants (EOPs) in municipal wastewater has raised concerns regarding their potential impact on human health and the environment. Constructed wetlands (CWs) have been identified as an effective and environmentally friendly solution for removing EOPs from municipal wastewater at a reasonable cost. This study investigated the performance of a full-scale hybrid constructed wetlands (HCWs) treatment system in reducing a total of 59 different types of EOPs. Findings show that the efficiency of the HCWs system in removing EOPs varied significantly depending on the specific physical and chemical properties of the pollutants. Pharmaceuticals (PhACs), personal care products (PCPs), and endocrine-disrupting chemicals (EDCs) were observed to be more effectively removed compared to bactericides, pesticides, and flame retardants, with removal efficiencies exceeding 54 %. Furthermore, the efficiency of the HCWs system in EOPs removal was observed to be influenced by seasonal variations. Specifically, the removal rate of PhACs in the spring and summer seasons reached 54.08 % ± 3.91 % and 61.04 % ± 8.58 %. The choice of substrate and plant species used within the system exhibited a notable impact on its overall removal efficiency. Moreover, the reduction effectiveness of EOPs across different treatment units varied significantly. Among these units, the bidirectional cross-flow filtration unit demonstrated superior reduction capabilities for PhACs and EDCs, with concentration reductions of 89.62 % and 86.34 %, respectively. Overall, this research emphasizes the importance of considering the specific characteristics of the pollutants and the system components to optimize the performance of CWs for EOPs removal in municipal wastewater.