Pankaj More and Kshama Khobragade
Abstract
Floating Treatment Wetlands (FTWs) have emerged as a sustainable, nature-based technology for restoring polluted lakes, rivers, and urban water bodies. Based on phytoremediation principles, FTWs utilize aquatic plants to absorb, transform, and immobilize nutrients, organic matter, and heavy metals from wastewater. Compared to conventional chemical and thermal treatment methods, FTWs are environmentally friendly, cost-effective, and energy-efficient, reducing both chemical inputs and operational energy while supporting ecological balance. FTWs are constructed using buoyant platforms that support emergent or floating vegetation, allowing roots to extend into the water column. This design promotes nutrient uptake, microbial colonization and biochemical processes such as nitrification, denitrification, and organic matter decomposition. The release of oxygen and root exudates further stimulates microbial activity, enhancing overall pollutant removal efficiency. Commonly applied plant species-including Canna indica, Phragmites australis, Typha domingensis, Vetiveria zizanioides, Water Hyacinth, and Water Lettuce have demonstrated significant potential in removing BOD,COD, total suspended solids, and heavy metals. Strategic combinations of complementary species and optimized plantâmicrobe interactions can further improve treatment performance. FTWs offer multiple ecological benefits, including habitat creation, improved water clarity, and increased biodiversity. Their low maintenance requirements, scalability, and adaptability make them suitable for municipal and industrial wastewater treatment, stormwater management, and mitigation of eutrophication. At the local level, small-scale FTWs have been implemented in urban ponds and drains in India, showing promising results in nutrient and pollutant removal. Nationally, several pilot and demonstration projects across Indian states have applied FTWs for municipal wastewater and stormwater management. Internationally, FTWs are widely used in North America, Europe, Australia, and parts of Asia for lake and river restoration, highlighting their global relevance and adaptability. Key design considerations, including plant density, water depth, hydraulic retention time, and platform materials, are critical for optimizing efficiency and sustainability. This review synthesizes local, national, and international research on FTW performance, pollutant removal mechanisms, plant selection, and ecological benefits. By integrating phytoremediation with optimized system design, FTWs offer a practical, cost-effective, and environmentally sustainable approach for freshwater restoration. Continued research on plant physiology, Microbial interactions and system optimization will further establish FTWs as a mainstream technology for revitalizing lakes and rivers while promoting long-term environmental protection.