Journal Articles

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    Impact of REE Mining on Coastal Groundwater: Numerical Modelling and Remediation Potential of Clay-Amended Laterites
    (Springer Nature, 2025) Bincy, B.; Devatha, C.P.; Thalla, A.K.
    Coastal aquifers are vulnerable to contamination due to extensive beach sand mining and effluents from processing plants, leading to heavy metal dispersion in groundwater. This study integrates hydrodynamic and geochemical modelling to predict contaminant transport and evaluates the effectiveness of clay-amended laterite mixtures in immobilising heavy metals. A 3D transient state finite element model (FEFLOW) was developed to simulate the transport mechanisms of titanium (Ti), iron (Fe), and magnesium (Mg) in the Chavara coastal zone, considering advective–dispersive transport and geochemical interactions. Results indicate significant contaminant plume migration along primary flow paths influenced by macro-scale hydrodynamics (groundwater flow) and micro-scale adsorption kinetics of laterite. Forecasting highlighted significant southwest movement of contaminants with maximum velocities of 18.40 m/day. The 7-year hydraulic modelling scenario predicts dispersion over 6.2–7.1 km2 area, emphasising groundwater vulnerability to pumping rates. Contaminant levels reached concentrations of Fe—180 ppm, Mg—48 ppm, and Ti—0.56 mg/L ppm. Simulation shows a 21.6% reduction in hydraulic head and a 71.34% decrease in storage capture with increased extraction, compared to a 0.61% head reduction from variations in specific storage. The study also explores heavy metal immobilization using laterite soil modified with bentonite, kaolinite, and zeolite clay through Langmuir and Freundlich adsorption models. Bentonite-amended laterites demonstrated the highest adsorption efficiency (Kd—54.8 L/kg for Ti, 22.1 L/kg for Fe, and 17.9 L/kg for Mg), attributed to its expansive interlayer structure and high cation exchange capacity. This research provides a multiscale interdisciplinary approach offering sustainable solutions for groundwater remediation in industrial coastal regions. © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2025.
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    Effect of hydraulic conductivity on soil moisture uptake under saline conditions for wheat crop
    (2013) Devatha, C.P.; Ojha, C.S.P.; Hari Prasad, K.S.; Thalla, A.K.
    Salinity in soil can decrease plant available water and cause plant stress. The pattern of root water uptake for wheat was studied for saline as well as non-saline condition using non-linear root water uptake model. Experiments have been conducted using a salinity level of 4 dS/m and freshwater condition. The effect of salinity on soil moisture has been studied by varying the crop coefficient as well as hydraulic conductivity. The correction factor to the crop coefficient approach is found to be unsuccessful. However, the correction factor to the hydraulic conductivity for a non-saline condition improves the simulation of soil moisture uptake in case of saline soils. The exponential form of the equation is established for the hydraulic conductivity to soil moisture relationship under salinity level and freshwater sample. The present work also substantiates that the non-linearity parameter of root water uptake model (O-R model) is successful in simulation of soil moisture depletion in the crop root zone and does not vary more than 10% in case of saline soils. © 2013 Indian Society for Hydraulics.
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    Assessment of soil moisture uptake under different salinity levels for paddy crop
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2016) Devatha, C.P.; Shankar, V.; Ojha, C.S.P.
    The core of salinity problems starts from the fact that irrigation waters contain some amount of dissolved salts. Soil moisture salinity is dependent on soil type, climate, water use, and irrigation. The root water-uptake pattern for paddies is studied for saline as well as nonsaline conditions in the present study using a nonlinear root water uptake model. Field crop experiments are carried out using irrigation water with two different levels of salinity (4 and 6.25 dS=m) and fresh water. The effect of salinity on soil moisture uptake is studied by two approaches, i.e., effect on crop coefficient and effect on hydraulic conductivity. Based upon the experimental observations for lowsaline (4 dS=m), high-saline (6.25 dS=m), and freshwater conditions, an exponential form of an equation is established for the hydraulic conductivity. The results obtained for soil moisture depletion in the crop root zone show significant improvement in prediction of soil moisture uptake for saline cases with the use of the obtained nonlinearity parameter. © 2016 American Society of Civil Engineers.
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    Green synthesis of iron nanoparticles using different leaf extracts for treatment of domestic waste water
    (Elsevier Ltd, 2016) Devatha, C.P.; Thalla, A.K.; Katte, S.Y.
    Green synthesis of iron nanoparticles being cost effective and ecofriendly treatment technique, is gaining importance nowadays. The aim of the present study is to prepare leaf extracts, precursor, and synthesis of iron nanoparticles and to evaluate its efficacy in treating domestic waste water. Synthesis of iron nanoparticles is done using various leaf extracts viz. Mangifera indica, Murraya Koenigii, Azadiracta indica, Magnolia champaca, and to check its potential for treating domestic waste water. Characterization of the synthesized iron nanoparticles is done by UV–Visible spectrophotometer, Scanning Electron Microscopy equipped with X-ray energy dispersive spectroscopy and Fourier Transform Infrared spectroscopy. The characterization results confirm the formation and presence of iron nanoparticles and biomolecules which could help in capping the nanoparticles. The effect of iron nanoparticles thus obtained is evaluated for simultaneous removal of total phosphates, ammonia nitrogen, and chemical oxygen demand. Among the different plant mediated synthesized iron nanoparticles, Azadiracta indica showed 98.08% of phosphate, 84.32% of ammonia nitrogen and 82.35% of chemical oxygen demand removal. Overall performance of Azadiracta indica synthesized iron nanoparticles showed satisfactory results compared to other leaf extracts for treating domestic waste water. © 2016 Elsevier Ltd
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    Effect of Green synthesized iron nanoparticles by Azardirachta Indica in different proportions on antibacterial activity
    (Elsevier B.V., 2018) Devatha, C.P.; Jagadeesh, K.; Patil, M.
    Green synthesis of iron nanoparticles has accumulated an ultimate interest over the last few years to their distinctive properties, applicable in various fields of science and technology. In the present study, synthesis of iron nanoparticles using Azadirachta Indica leaf extract is performed. Different proportions of precursor (ferrous sulphate) to leaf extract were prepared by varying the volume quantity of leaf extract from 1:1 to 1:5. Their morphology, structure and size distribution is confirmed by Scanning Electron Microscope along with X-ray energy dispersive spectroscopy and Fourier Transform Infrared spectroscopy analysis. Presence of accountable polyphenols such as total phenolic content by Folin-Ciocalteau(FC) method (20 mg per gram of leaf extract) and gallic acid(0.280 mg/g), caffeic acid(0.278 mg/g) & catechin(0.532 mg/g) for synthesis conciliation and were quantified by High Performance Liquid Chromatography. Its performance is evaluated on treatment of petrochemical refinery waste water to assess Chemical Oxygen Demand(COD) and nitrate removal for different proportions. The performance of COD removal (77%) and nitrate removal(74%) for 1:5 on 5th day is observed to be efficient. To further study this effect, size of FeNPs formed and concentration of polyphenols were taken into consideration. Antibacterial activity of synthesized iron nanoparticles from AI leaf extract on bacteria (Escherichia Coli, Pseudomonas Aeruginosa, and Staphylococcus Aureus) is accomplished by well diffusion method. Size of FeNPs achieved for 1:2 ratio was 98–200 nm and for all proportions varying between 120 and 600 nm due to agglomeration enhanced bacterial decay. It was portrayed that there was an increase in the inhibition zone as the proportions increased from 1:2 to 1:5. Hence for the contact time of 48 h, 1:5 found to be effective in inhibiting more number of bacterial cells compared to other proportions. © 2017 Elsevier B.V.
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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
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    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.
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    Investigation of physical and chemical characteristics on soil due to crude oil contamination and its remediation
    (Springer Verlag, 2019) Devatha, C.P.; Vishnu Vishal, A.; Purna Chandra Rao, J.
    Oil contamination causes serious geoenvironmental concern and adversely affects the soil environment due to the release of toxic by-products. Hence, the aim of the study was to investigate the influence of oil contamination on soil physical and chemical properties and phytoremediation as a treatment option based on field studies conducted for analyzing significant parameters. The sites selected were near National Institute of Technology, Surathkal, Karnataka (site-1), and another is close to the oil refinery (Kuthethur, Karnataka, India, as site-2). Phytoremediation of oil-contaminated samples was carried out by Chromolaena odorata. The evaluation of soil physical and chemical properties includes field and laboratory tests. A pumping test was conducted to estimate aquifer parameters in the field. The hydraulic conductivity for field soil sample (unsaturated condition) is carried out by a filter paper test. Laboratory tests to evaluate physical and chemical parameters include total petroleum hydrocarbons of contaminated (crude oil varying from 0 to 10% at an interval of 2%) and uncontaminated samples and plant parameters. Characterization of contaminated and uncontaminated soil sample was performed by Fourier transform infrared (FTIR) spectroscopy. The results obtained reveal that physical properties of soil (moisture content, liquid and plastic limit) got affected due to oil contamination. Relative hydraulic conductivity was established as 0.46 (uncontaminated) and 0.57 (contaminated) for soil samples and led to the conclusion that hydraulic conductivity was drop down by 10% due to oil contamination. Total petroleum hydrocarbon analysis reveals that the uptake/presence of hydrocarbons by showing increased concentration in contaminated soils (5% and 10%) by the plant species. This is further confirmed by FTIR results. The TPH concentrations in the contaminated soils were reduced up to 50–60% and also showed better plant growth after 7 weeks of transplantation. Hence, considered plant species possess high potential for degrading oil contaminated in the soil. © 2019, The Author(s).
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    Prioritizing cropping alternatives based on attribute specification and comparison using MADM models
    (King Saud University info@ksu.edu.sa, 2019) Devatha, C.P.; Thalla, A.K.
    This paper presents a logical procedure and its effectiveness to handle set of alternatives for attaining rabi cropping pattern by multiple attribute decision making (MADM) approach which includes methods viz. simple additive weighting (SAW), weighted product method (WPM), technique for order preference by similarity to ideal solution (TOPSIS) and preference ranking organization method for enrichment evaluations (PROMEHTEE). The study area is concerned with banahil distributary of akaltara branch canal of Hasdeo Bango irrigation command, Janjgir-Champa district, Chattisgarh, India. It covers 8 villages of Akaltara Block and 14 villages of Pamgarh Block in Janjgir-Champa District. Information on various attributes/criteria like type of crops (wheat, mustard, gram, safflower, sunflower), type of soil (clay, clay loam, sandy loam) cropped area, water usage, cost of production, cost of cultivation (including irrigation cost) and sale price of crops had been collected from various government departments (Agriculture and Water Resources) etc. and group of farmers from the local command area. Results obtained with MADM approach is compared with the non-linear optimization model (NLP) developed using LINGO standard optimization package. Based on the above decision making method and LINGO model results, wheat is found to be most profitable crop followed by sunflower. Performance of MADM is found to be satisfactory and ranking had been obtained for the crops considered in the study. © 2017 The Authors
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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).