Evaluation of the Efficiency of Duckweed (Lemna minor L.) as a Phytoremediation Agent in Wastewater Treatment in Kashmir Himalayas

摘要

In the present study, the efficiency of duckweed (Lemna minor L.) as an effective natural biological tool in wastewater treatment was examined in an outdoor aquatic system. Duckweed plants were inoculated into wastewater and tap water systems for treatment over fifteen day’s retention periods under local outdoor natural conditions. Water samples were taken below duckweed cover after fifteen days to assess the plant’s efficiency in purifying waste water from different pollutants. For comparison, the plants were also grown in tubs containing tap water. The results show that concentrations of Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Copper (Cu), Zinc (Zn), Nickel (Ni), Chromium (Cr), Cadmium (Cd) and Lead (Pb) decreased by 93.4%, 99.9%, 93.9%, 98.5%., 91.9%, 85.0%, 95.0%, 90.0%, 99.8%, 99.5% and 95.0% respectively in waste water and subsequently these elements exhibited an increasing concentration in the plant body. Almost similar results were obtained when the plants were grown in tubs containing tap water. Biochemical parameters viz. chl-a, b, total-chl, carbohydrates and proteins as well as nutrient status of the macrophyte increased after the completion of the retention period both in waste and tap water. Results confirm that duckweeds can effectively be used for wastewater treatment systems.