Floating Treatment Wetlands: A Review of Design, Performance, and Application for Sustainable Water and Wastewater Management

Nature-Based Solutions (NBSs) have proven to be effective and reliable for climate change adaptation and risk reduction. Among these, Floating Treatment Wetlands (FTWs) have recently gained significant attention. FTWs are floating NBS systems that enhance the biological self-cleaning capacity of aquatic environments. Since the performance of FTWs is derived from the rhizosphere suspended beneath a buoyant frame and the interactions between biofilm and macrophytes (rhizosphere), it is crucial to operate and design FTWs in a way that supports the specific pollutant removal pathways of FTWs. Key parameters to consider are plant selection, choice of planting medium, length of plant establishment phase, treatment medium depth, surface coverage ratio, hydraulic retention time (HRT), and placement of FTWs. Despite recent advances, there is a lack of established guidelines for FTW development, which has led to diverse construction and operational practices. This review aims to collate the latest advances in FTW research, identify gaps, and suggest a coherent classification and construction framework. By highlighting best practices, performance factors, and operational parameters, this review seeks to guide the future development and implementation of FTWs.