Determining the nutrient removal capacity of duckweed Wolffia globosa under artificial conditions

Aquatic vegetation like duckweed (Wolffia globosa) can eliminate contaminant from wastewater, which also can be commercial and possible options for wastewater treatment. Thus, this study aimed to estimate the nutrient removal capability of Wolffia globosa under artificial culture conditions. The nutrient removal capacity of W. globosa was evaluated in a 12-day growth trial with mineral mixture containing 173.6 mg/litre nitrogen; 40.3 mg/litre phosphorous; 100 mg/litre potassium and 0.6 g/litre as a reference fertilization rate (RF) along with five other different [RF/2; RF/4; RF/8; RF/16; RF/20 and Control (no fertilizers)] NPK fertilization rates under natural sunlight. In all the treatments, the concentrations of nitrate-nitrite, ammonia, nitrate and ortho-phosphate, decreased over the experimental period in a statistically significant (p=0.05) manner. At the end of the experiment, the total dissolved inorganic nitrogen (T-DIN) in the culture media was reduced by 99. 57% (RF/20), 100% (Control group -no fertilizers) while Ortho-phosphate (OP) by 100% in RF/16, RF/20 and control group, respectively. It was concluded that the Wolffia globosa is a suitable aquatic plant for nutrient removal under natural sunlight.