Faculty Publications
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Item Performance evaluation of horizontal and vertical flow constructed wetlands as tertiary treatment option for secondary effluents(Springer Verlag, 2019) Thalla, A.K.; Devatha, C.P.; Anagh, K.; Sony, E.Constructed wetlands (CWs) are simple low-cost wastewater treatment units that use natural process to improve the effluent water quality and make it possible for its reuse. In the present study, a comparison is made between horizontal subsurface flow (HSSF-CW) and vertical flow (VFCW) constructed wetland in effectively post-treating the effluents from the secondary biological treatment system. Locally available plants, viz. Pennisetum pedicellatum and Cyperus rotundus, which are abundantly available in the Western Ghats, were used in the wetland. A pilot-scale study was undertaken in National Institute of Technology, Karnataka Campus. The experiments were conducted at two hydraulic retention times, i.e., 12 h and 24 h. The experimental study was carried out in February 2018 to May 2018. Concentration-based average removal efficiencies for HSSF-CW and VFCW were BOD, 77% and 83%; COD, 60% and 65%; NH4 +–N, 67% and 84.47%; NO3–N, 69% and 66.75%; and PO4–P, 85% and 90%, respectively. VFCW showed a better overall removal efficiency than HSSF-CW by 7.14%. Thus, constructed wetland can be considered as a sustainable alternative to the tertiary conventional treatment of domestic wastewater, thus making it possible for reuse. © 2019, The Author(s).Item Experimental investigation for treating ibuprofen and triclosan by biosurfactant from domestic wastewater(Academic Press, 2023) Jayalatha, N.A.; Devatha, C.P.The presence of emerging pollutants of pharmaceutical products and personal care products (PPCPs) in the aquatic environment overspreads the threat on living beings. Bioremediation is a promising option for treating wastewater. In the present study, an experimental investigation was carried out to produce a biosurfactant by Pseudomonas aeruginosa (MTCC 1688) for the removal of Ibuprofen (IBU) and Triclosan (TCS) from domestic wastewater. It was performed in three stages. Firstly, the production and optimization of biosurfactant was carried out to arrive at the best combination of crude sunflower oil, sucrose and ammonium bicarbonate (10%: 5.5 g/L: 1 g/L) to yield effective biosurfactant production (crude biosurfactant) and further extended to achieve critical micelle concentration (CMC) formation by dilution (biosurfactant at 10.5%). The stability of the biosurfactant was also confirmed. Biosurfactant showed a reduction in the surface tension to 41 mN/m with a yield concentration of 11.2 g/L. Secondly, its effectiveness was evaluated for the removal of IBU and TCS from the domestic wastewater collected during the dry and rainy seasons. Complete removal of IBU was achieved at 36 h & 6 h and TCS at 6 h & 1 h by crude biosurfactant and biosurfactant at CMC formation for the dry season sample. IBU removal was achieved in 2 h by both crude and biosurfactant at CMC and no TCS was detected in the rainy season sample. Thirdly, biotransformation intermediates of IBU and TCS formed during the application of the biosurfactant and degradation pathways are proposed based on the Liquid Chromatography-Mass Spectrometry (LC-MS) and it indicates that there is no formation of toxic by-products. Based on the results, it is evident that biosurfactant at CMC has performed better for the removal of IBU and TCS than crude biosurfactants without any formation of toxic intermediates. Hence, this study proved to be an eco-friendly, cost-effective and sustainable treatment option for domestic wastewater treatment. © 2022 Elsevier Ltd