Constructed Wetlands and Water Security: A Review of Contaminant Removal Efficiency in Textile Effluents for Reuse

Abstract

The reuse of treated effluents is an essential strategy to strengthen water security and reduce pressure on freshwater sources, particularly in water-intensive sectors such as textiles. This study systematically reviewed the efficiency of constructed wetlands (CWs) in removing contaminants from textile effluents and assessed their implications for safe water reuse. The review followed PRISMA guidelines, with searches conducted in Google Scholar, ScienceDirect, and the Capes Periodicals portal. A total of 3,424 records were identified, of which 55 met all eligibility criteria and were included in the qualitative synthesis. The findings show that CWs configured as vertical, horizontal, and hybrid flow systems achieve average removal efficiencies above 80% for BOD, COD, and apparent color, and can exceed 95% when coupled with complementary treatment processes. In addition, CWs reduce heavy metals and micropollutants, enabling non-potable reuse in accordance with NBR 16783/2019 and CONAMA Resolution 430/2011. Overall, the analysis indicates that constructed wetlands constitute a sustainable, low-cost, and operationally robust technology with strong potential to expand the availability of reclaimed water and to contribute to water security in urban and industrial settings.