NUTRIENT REMOVAL EFFICIENCY ASSESSMENT IN LEMNA MINOR COVERED WASTEWATER SYSTEM: AN EXPERIMENTAL INVESTIGATION

摘要

Aquatic macrophytes in domestic wastewater treatment is receiving attention over last few years. Duckweed-based pond system may be a feasible option for organic matter and nutrient removal, particularly for country like India where sunshine is available in plenty for photosynthesis. Nutrients rich effluents when discharged into water bodies causes eutrophication, leading to algal blooms, which die and depletes oxygen and make the water unfit for beneficial use. In the present study the efficiency of duckweed (Lemna minor) as an alternative cost effective natural biological tool in wastewater treatment was examined in an outdoor aquatic system. Duckweed plants were inoculated into raw domestic sewage in a batch reactor over 28 days retention time under local outdoor natural conditions. Samples were taken below duckweed cover after every 7 days to assess the system efficiency. System was found to be efficient in nutrient removal and restricts algal growth.