RESUMEN
Floating treatment wetlands (FTW) are technologies that have stood out for their efficiency, ease of installation and maintenance. They consist of macrophytes emerging in a floating structure that keep the plant roots in direct contact with the effluent regardless of the water flow variation over time, allowing the removal of pollutants by various processes. The application of FTWs for the treatment of domestic wastewater has the advantage of low costs in terms of removing nutrients and at the same time reducing the cost of maintenance and energy consumption when compared to the conventional centralized treatment of effluent. The lack of wastewater treatment in areas distant from urban centers is even more limited, mainly due to the high cost of tubing and pumps for the effluent to reach the treatment plants. Therefore, the objective of this study was to research FTW systems applied to the decentralized treatment of domestic wastewater. First, a bibliometric analysis was conducted comparing the main issues involving FTW, and the challenges regarding the integration of FTW and domestic wastewater treatment systems. The feasibility of the floating system as a decentralized treatment approach were discussed, as well as the removal of nutrients in domestic wastewater, which was the most covered topic by researchers who developed studies in the area. In addition, other technologies are being integrated into the phytoremediation systems seeking to improve the quality of the treated effluent and assessing the potential reuse in the homes where they are generated and treated, determining the costs and space requirements for the entire process. There is a large research gap regarding the treatment of domestic wastewater by FTW in decentralized systems, mainly in terms of operation, cost assessment and reuse Therefore, further investigations in order to better understand the performance of the process and the reactions that occur with physical, chemical and microbiological removal mechanisms are still necessary.
RESUMEN
Floating treatment wetlands (FTWs) have attained tremendous popularity for water purification purposes. Through this phyto-technology, naturally occurring macrophytes are allowed to grow on the water surface on a buoyant raft or a rigid support, keeping the plant roots permanently in contact with the water and removing pollutants via several processes. The objective of this study was to review studies that have developed FTWs and to perform a bibliometric analysis using three keywords: "Floating", "Treatment" and "Wetlands". From bibliometric analysis using VOSviewer software and the Web of Science database, it was possible to verify the number of publications over the years and the countries and authors with the most published articles on these systems and other related terms. Subsequently, a review was performed on the main mechanisms of pollutant removal by FTWs as well as experiences and recommendations for major design and operating aspects for their application, such as water depth, hydraulic retention time (HRT), floating mat, water surface coverage, artificial aeration, plant selection and pruning or harvesting. It was verified that FTWs are a potential technology for treating several wastewater types and water remediation under different conditions. Even with the increasing number of publications in recent years, many design and operation aspects related to system performance still demand more research in order to better understand the relations between macrophytes and other pollutant removal mechanisms and to thereby improve the treatment efficiency of FTW systems.