Efficacy of Treatment of Rice Mill Wastewater using Canna Indica

Abstract

This experiment was carried out to assess the efficiency of the ornamental plant Canna indicafor the removal of pollutants from the rice mill wastewater especially for suspended and dissolved solids, organics and nutrients in a pilot scale vertical subsurface flow constructed wetlands (VSSFCWs). Th'0 units of constructed wetlands were established using two sets of cylindrical buckets with same size and dimensions and with growing media comprised of three layers (soil-sand-gravel), one as control (without Canna indica) and the second as experimental unit with Canna indica. The inlet and outlet wastewater samples were collected from November 2016 to January 2017 with retention time of 4 days and were analyzed for various water quality parameters to study the significance of Canna indica in treating wastewater. The results revealed that the removal efficiency of Canna indicafor suspended solids (26.3% ± 12.1), dissolved solids (18.4% ± 10.1), BOD5 (45.8% ± 6.9), COD (41.1% ± 9.8), nitrate (48.6% ± 17.9) and for phosphate (81.5% ± 21.2)from the wastewater while the growing media too reduced the suspended solids, dissolved solids, BOD5, COD, nitrate, phosphate by 18%, 11%, 21%, 24%, 26% and 36% respectively through sedimentation. It could be concluded that Canna indica reduced the pollutants significantly from the rice mill wastewater. Hence, this model could be recommended to treat wastewater in the polluted sites of the rice mills