Recent research challenges in constructed wetlands for wastewater treatment: A review

Abstract The review paper sis based on the analysis or nearly 700 research papers published during 2019 and the first half of 2020 and indexed by Web of Science under the password “constructed wetlands for wastewater treatment”. Out of this number 132 papers dealing with “new” topics such as new wastewaters treated in constructed wetlands (CW), new filtration materials, role of vegetation, floating treatment wetlands, microbiology of CW, greenhouse gas emissions from CWs, sustainability and secondary benefits of CWs. For the deeper analysis the supporting literature from previous periods has been cited. The analysis indicates increasing popularity and diversification of types and tasks of CWs. This supports the need for further research of processes and design-related properties of CWs. The research in full scale CWs and long-term studies are only rare and in order to upgrade the CWs technology, research must be also carried out in the field under full-scale conditions.