Wastewater treatment using combined biological and constructed wetlands technique in paper mills

Constructed wetland is becoming a popular for the treatment method for different sources of waste water and it has been an alternative to conventional wastewater treatment method with some limitations in the operational and financial aspects. Several types of constructed wetland methods are in practice for treating the wastewater. Among the different methods horizontal flow constructed wetland, vertical flow constructed wetland, and integrated flow constructed wetland methods were identified to treat the paper mill effluent. Based on the selection of lab-scale model, namely IF-integrated flow setup was designed according to the guidelines of Environmental Protection Agency and Tennessee Valley Authority methods. The size of the lab-scale model was designed as length 0.6 m, width 0.4 m, depth 0.3 m. Paper mill wastewater sample both raw and treated effluents were collected from paper mill located at Erode city (South India). The same was analyzed for BOD (bio chemical oxygen demand), chemical oxygen demand (COD), pH, total dissolved solids, dissolved oxygen, and hardness. Based on the analysis it was found that the raw wastewater has 3–4 times greater than the discharge limit of BOD and COD (30 and 250 mg/l). The obtained results implied that constructed wetlands are suitable for the treatment of waste water in mill.