Treatment of micropollutants contaminated wastewater effluent by constructed wetlands

The presence and fate of micropollutants and their transformation products in the aquatic environment has raised increasing concern in recent years due their potential hazard at low concentration (ng/L-μg/L). Conventional WWTPs don’t remove micropollutants sufficiently from the wastewater. Constructed wetlands (CWs) are a promising alternative as a post-treatment technique to remove micropollutants from the effluent of WWTPs, possibly in combination with pre-treatment techniques (e.g. advanced oxidation processes or aeration).

The aim of this study is to optimize design parameters of CWs to enhance the removal efficiency of micropollutants, and explore the effect of pre-treatment processes (e.g. advanced oxidation processes or aeration) to CWs to enhance the overall treatment performance.

Technological challenges

  • Sorption, plant uptake and phytodegradation, and biodegradation are main removal mechanisms for micropollutants in CWs. This study will optimize these removal mechanisms by identifying the optimal support matrixes, plant species and activated sludge to enhance micropollutant removal in CWs.
  • CWs are a dynamic eco-system and changing one of the design parameters can influence the performance of a CW. After optimization of the individual removal mechanisms, we will study the overall removal of mciropollutants in mesocosm-scale CWs in order to understand the interaction between these removal mechanisms.
  • To further improve micropollutant removal in CWs, various pre-treatment processes will be studied, e.g. UV/H2O2, UV/TiO2 or aeration. We will test possible combinations of AOPs or aeration as pre-treatments for CWs and as a complementary treatment process to remove micropollutants and their transformation products.
  • Finally, the removal of micropollutants in pilot-scale CWs and full-scale CWs is crucial. We will study CWs under real conditions with real wastewater effluent.