State-of-the-Art Utilization of Aquatic Plants in Water Pollution Control

Abstract

Research, pilot-scale and operational studies conducted within the past 15 years have shown that aquatic macrophyte-based treatment systems offer a promising, low-cost method for removing contaminants from wastewaters and polluted natural waters. The vascular plants cultured in such treatment systems perform several functions, including assimilating and storing contaminants, transporting O2 to the root zone, and providing a substrate for microbial activity. Among the various types of aquatic treatment systems, pond systems containing floating macrophytes such as the water hyacinth are most commonly utilized for wastewater treatment in tropical and sub-tropical regions, whereas in temperate regions, emergent plants cultured in artificial wetlands (e.g., root zone method, nutrient film techniques) appear to be more appropriate. However, due to concerns about system management and reliability, aquatic plant treatment systems are currently used only on a limited basis throughout the world. This review discusses the general performance, contaminant removal processes and criteria for plant selection in aquatic macrophyte wastewater treatment systems. Case studies on the use of floating plants for domestic wastewater treatment and the renovation of eutrophic lake water are presented, and future research needs for aquatic macrophyte-based wastewater treatment systems are discussed.