The use of constructed wetlands (CW) to treat domestic as well as industrial wastewater is rapidly emerging as a viable alternative in India. Constructed wetland systems offer several potential advantages as a wastewater treatment process. These advantages include simple operation and maintenance and lower construction and operating costs. The study evaluated the effectiveness of the subsurface flow constructed wetland for pulp and paper mill wastewater treatment and also the effectiveness of plant species. A pilot scale study was conducted to examine the feasibility of a CW system for treatment of pulp and paper mill wastewater during summers as well as winters at different hydraulic retention time (HRT) such as 1.5 days, 3.5 days and 6.5 days. Wetland beds were prepared with easily available plants such as Typha angustifolia and Canna indica. Specific performance objectives were to decrease biochemical oxygen demand (BOD), chemical oxygen demand (COD), total solids (TS) and color. Comparison of mean inlet and outlet concentrations showed that the CW system could effectively reduce the output of TS (87.6 ± 1.1%), COD (86.6 ± 2.0%), BOD5 (80.01 ± 0.1%), color (89.4 ± 0.6%) during summer and TS (72.15 ± 0.71%), COD (70.94 ± 2.3%), BOD5 (72.07 ± 2.2%) and color (74.90 ± 0.47%) during winter at 3.5 days HRT.
Purification of pulp and paper mill effluent through Typha and Canna using constructed wetlands technology
