Exploring Nature-Based Solutions for Environmental Challenges in Macau: A Pilot Study on Floating Wetlands for Water Pollution Remediation

Floating wetlands are artificially constructed platforms that support aquatic vegetation growing hydroponically. These systems are considered a nature-based solution (NBS), leveraging the natural processes of plants, microbes, and associated microorganisms to filter and enhance water quality by removing pollutants such as nutrients, heavy metals, and organic contaminants. In Macau SAR, China, a coastal city with significant water bodies, floating wetlands offer a promising solution to mitigate water pollution. Macau faces considerable environmental challenges due to urban runoff, industrial discharge, and limited natural wetlands. The implementation of floating wetlands can effectively address these issues. This study aims to evaluate the use of floating wetlands for the remediation of water pollution, particularly eutrophication, in both freshwater and coastal wetlands. A pilot-scale floating platform, made of bamboo and coconut fibers, was set up as a base for the vegetation. Local coastal mangrove species such as Kandelia obovata and Aegiceras corniculatum, along with freshwater wetland plants like Thalia dealbata, Canna sp., and Iris sp., were anchored between the bamboo tubes and secured with coconut fibers and polyethylene nets. Nutrient concentrations in the surrounding waters were measured before deployment and monitored thereafter. The growth conditions of the plants and the biodiversity within the floating wetlands are also being monitored. Biofilm from the roots of the plants will be collected and processed for sequencing to identify associated microorganisms involved in phytoremediation. We expect that the presence of floating wetlands will improve water quality and biodiversity in the system. Acknowledgments: Calheiros C.S.C. is thankful to Strategic Funding UIDB/04423/2020, UIDP/04423/2020, and LA/P/0101/2020 through national funds provided by FCT.