Assessment of Constructed Wetland in Nutrient Reduction, in the Commercial Scale Experiment Ponds of Freshwater Prawn Macrobrachium rosenbergii

A free water surface constructed wetland (CW) was integrated into two commercial ponds of Macrobrachium rosenbergii, to evaluate the role of CW in reducing the excess nutrient concentration and other pollutants produced from the aquaculture waste. Hydraulic residence time was kept constant (24 h). There was a significant (p < 0.05) decrease in total suspended solids (TSS, 73.2 ± 15.4 %) and total nitrogen (TN, 39.6 ± 44.2 %) between wetland inflow and wetland outflow. The performance of the CW was highly impacted by the low concentration of dissolved nutrients at the inflow of CW. Results showed about 43.8 ± 24.6 % NO₃^-, 25.7 ± 23.0 % NH₄⁺, 14.3 ± 1.0 % NO₂^-, 28.4 ± 18.8 % DIN and 13.1 ± 10.0 % PO₄^3- were removed. In agreement with previous published investigations, comparing values of pollutants before and after recirculation, this study concludes that a CW system can provide good water quality and minimize external water input.