Faculty Publications

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Isolation and identification of Pseudomonas from wastewater, its immobilization in cellulose biopolymer and performance in degrading Triclosan
(Academic Press, 2019) Devatha, C.P.; Narasimhappa, N.
Triclosan (TCS) is a well-known emerging contaminant got wide use in daily use products of domestic purpose, which provides the way to enter the ecological cycle, and is preferably detected in sewage treatment plants. In this study, TCS degrading bacteria (TDB) was isolated and identified from a wastewater treatment plant at the National Institute of Technology-Karnataka, Surathkal (NITK), India. The isolate was reported as Pseudomonas strain by performing 16S RNA Sequencing using BLAST analysis. Bacterial growth depends upon several environmental factors. Hence its growth optimization was carried out by response surface method (RSM) based central composite design (CCD) and validated by the artificial neural network (ANN). The Parameters or inputs used for optimization are pH, time (days), agitation (rpm) and sorbent dosage (?g/L). Experiments were conducted in batch mode to achieve optimum growth of bacteria based on RSM trial runs. The RSM model predictions were in better agreement with the experimental results and it was confirmed by ANN. The deviation lies within ±10% with experimental results compared to ANN for maximum trials. Hence optimized parameters were established and arrived at pH - 7, time - 13 days, agitation - 150 rpm, dosage - 1.5 ?g/L presented 69% removal of TCS. Minimum inhibitory assay of isolated strain was conducted to identify the degradation capacity of TCS and it was found out to be lesser than 0.025 mg of TCS. Later the strain was immobilized in two different matrices. One is biopolymer extracted from cellulose (Water Hyacinth) along with sodium alginate and second is free bacteria with sodium alginate and was made in the form of beads. The removal of TCS by TDB-cellulose-alginate (BCA) and TDB-Alginate (BA) beads were 58% and 30% respectively. Hence it was concluded that BCA beads showed effective removal compared to BA beads. Therefore, isolate can degrade TCS when the concentration ranges from 0.025 mg/L to 5.5 ng/L. © 2018 Elsevier Ltd
Investigation on leaching behaviour of toxic metals from biomedical ash and its controlling mechanism
(Springer Verlag service@springer.de, 2019) Krishnamurthy, K.M.; Devatha, C.P.
It is comprehensible that disposal of biomedical ash (BMA) is a serious threat to human life and to the environment compared to any other type of waste without proper treatment. In the present study, it is focused in studying the leaching behaviour and its controlling mechanism to predict the contamination levels of BMA. Experimental investigation was carried out to determine the physico-chemical properties of BMA. The morphological and mineralogical composition was performed by SEM equipped with EDAX and XRD. A leaching pattern was identified for various heavy metals simultaneously (Hg, Se, As, Fe, Cd, Zn, Pb, Ca, Co, Ni, Cr and Cu) by varying pH (3, 5, 7, 9, and 11) via a pH-dependent batch leaching test using AAS and ICP. Major oxidation states of leached mineral/metal were established by Visual MINTEQA 3.1. Leaching test results show that a high concentration of Hg (9.3 mg/l), Se (2.4 mg/l) and As (9.7 mg/l) at pH 11 was obtained. Characterisation studies substantiate 60% of calcium silicate presence and major minerals like ettringite, calcite and thermonatrite. Geochemical modelling reveals that leached elements were solubility controlled except As and Se. It is inferred that, presence/formation of ettringite, calcite and thermonatrite minerals are responsible for immobilizing/reduced leaching of toxic heavy metals in alkaline environment except for Hg, Se and As as they are highly mobile in an alkaline condition which can be reduced by adopting a suitable pretreatment option so as to reduce the contamination levels of handling even untreated waste disposal. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Investigation of Ti contamination and transport mechanisms in ferruginous soils: Impacts of ilmenite and rutile processing and immobilization using clay amendments
(Elsevier B.V., 2025) Bincy, B.; Devatha, C.P.; Thalla, A.K.
Titanium (Ti) contamination from coastal mining activities poses significant threats to groundwater and soil quality, especially in regions with ferruginous soils (FS). This study investigates Ti transport and immobilization in FS, assessing its natural retention capacity and the enhancement achieved using bentonite, zeolite, and kaolinite amendments. Environmental assessment identified industrial discharge as the primary source, with elevated Ti in soil (271.67 ppm), surface water (0.56 ppm), and groundwater (0.45 ppm), forcing 86 % of households to rely on alternative sources. The 3D flow model demonstrated that FS reduces Ti mobility; however, rising inlet to outlet head differences (6-12 cm) led to increased flow rates (0.1–0.7 cm3/min), resulting in elevated Ti concentrations in wells 2 and 3(8.55 ppm and 7.23 ppm). Ti peaks observed in the wells were the result of desorption following initial adsorption, reflecting the breakthrough pattern. Batch adsorption tests (0–1000 ppm Ti, 25–27 °C, 1:20 ratio, pH-3.9-5.5) revealed chemisorption dominance at low concentrations (Kd = 28.5 L/kg, KL = 33.39 L/kg) and multilayer physisorption at higher loads (qm = 11.09 mg/g, Kf = 88.11 L/kg), modelled using Linear, Langmuir, and Freundlich isotherms. XRD and SEM-EDS confirmed Ti incorporation into stable mineral phases (Al8Ti32Cl48, Fe4Ti2Cl7, Ti3O5) with increased retention (4.1–7.8 %). Among amendments, bentonite-enhanced FS showed the highest Ti retention (97.5 %, Kf = 478.5 L/kg) at 10–20 % dosage. This integrated experimental framework is transferable to other heavy metal-affected coastal aquifers, where it supports predictive contaminant transport and groundwater protection strategies aligned with the Sustainable Development Goals. © 2025

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