Faculty Publications

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Publications by NITK Faculty

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Author: search.filters.author.Devatha, C.P.Subject: search.filters.subject.Effluent treatment

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    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).
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    Biomedical Ash as a Soil Stabilizer: Immobilizing Toxic Metals Through Biomineralization
    (Springer, 2025) Kothuri, M.; Devatha, C.P.
    Biomedical ash is the residual matter from biomedical waste incinerators. Despite its superior characteristics as a construction material, biomedical ash is usually averted as an additive due to the mobility of toxic heavy metals. Arresting heavy metal mobility has gained the interest of scientific communities due to the ever-increasing waste and continuous demand for construction materials. This research investigated the application of modified ash by calcium carbonate biomineralization as a soil stabilizing agent in highly plastic clays. Initially, the nutrient medium for the indigenous Bacillus cereus bacteria was optimized for maximum urease activity. The ability of biomineralization to arrest mercury, chromium, zinc, lead, iron, copper, cadmium, barium, arsenic, titanium, and selenium in biomedical ash by calcium carbonate biomineralization was determined through a leaching test. The characteristics of modified ash were determined by FESEM, XRD, FTIR, and TG analyses. Adding modified ash correlates with the increasing soil strength, suggesting the suitability of calcium carbonate biomineralization in immobilizing toxic heavy metals and simultaneously enhancing soil strength. © The Institution of Engineers (India) 2025.