Role of Colocasia esculenta in Constructed Wetlands for Treating Rice mill Wastewater

This study was conducted to assess the efficiency of aquatic macrophyte – Colocasia esculenta to treat the rice mill wastewater especially for (suspended and dissolved) solids, organics, and nutrients in a pilot scale vertical subsurface flow constructed wetlands. Two units of constructed wetlands were assembled with growing media comprised of three layers (soil-sand-gravel), one as control (without macrophyte) and the second as experimental unit (with macrophyte). The collected inlet and outlet samples were analyzed for various water quality parameters and statistical analysis was done to study the significance of Colocasia esculenta in wastewater treatment. The results revealed that Colocasia esculenta was effective in reducing suspended solids (34.5% ± 15.9), BOD5 (53.0% ± 5.7), COD (50.3% ± 11.1), nitrate (55.7% ± 13.5) and phosphate (76.1% ± 20.5) from the wastewater. Besides this, the growing media itself significantly reduced suspended and dissolved solids through sedimentation. Authors claim the Colocasia esculenta was observed to be efficient in treating rice mill wastewater compared to Canna indica for the same experimental conditions. In addition, long term operation of this experiment is needed to study the interactive role of microorganisms to make the treatment system highly efficient, cost effective and sustainable.