Browsing by Author "Shrihari, S."

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    A comprehensive analysis of water quality of open wells at Alevuru and Badagabettu-76 village of Udupi Taluk, Karnataka, India
    (Institute of Physics, 2024) Sharma, H.S.; Rakesh, R.; Shrihari, S.
    The availability of pure water is one of the most essential requirements for all living organisms. In rural areas of Udupi, Karnataka, India, well water serves as the primary source of water for residents. Hence the objectives of the study were to find the physical and chemical characteristics of the well water sources in Udupi taluk; and to assess the suitability of the well water sources in Udupi taluk for drinking purposes by determining water quality index (WQI). Water samples (n=24) were collected from open wells from Alevuru and Badagabettu-76 villages of Udupi taluk during October 2023. Water quality parameters analyzed were pH, total dissolved solids, electrical conductivity, turbidity, total alkalinity, total hardness, dissolved oxygen, nitrate, chloride, sulphate, chemical oxygen demand and iron. The WQI revealed that the well water in majority of the sites was fit for drinking. All parameters were within the permissible limits in majority of the wells except for iron and pH. © Published under licence by IOP Publishing Ltd.
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    A study was conducted to assess the performance of the domestic wastewater treatment plant designed for the New Mangalore Port Trust (NMPT) township, Panambur. The data of raw, aerated and treated wastewater samples were collected for a period of 24 months (January - 1998 to December 1999) with a sampling frequency of one month. The sewage treatment plant is designed to treat an average flow of 1.2 MLD. The treatment scheme is based on extended aeration activated sludge process and consists of bar screens, collection sump, grit channel, aeration tank, secondary clarifier, treated sewage sump and sludge drying beds. The salient design features of the plant, process description, physico-chemical characteristics of sewage at different stages of treatment, sludge and grit are presented. Various parameters were tested in the laboratory and analyzed to assess the performance of the treatment plant. The effluent concentrations revealed that the treatment plant was found to be working quite satisfactorily though the influent wastewater quality was varying considerably. © Enviromedia.
    (Performance evaluation of sewage treatment plant - A case study) Yaragal, S.C.; Shrihari, S.
    2004
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    Assessment of ferrous slag with relevance to physico-chemical properties
    (Springer, 2020) Anjali, M.S.; Poorani, M.; Shrihari, S.; Sunil, B.M.
    Blast furnace slag is generated as a by-product in the production of iron. Large quantities of slag are visible in the industrial premises that can have adverse effects on the environment. To mitigate such problems, proper environmental management of slag is of great concern. In this regard, a qualitative and quantitative evaluation of ferrous slags such as crystallinity, surface morphology, and elemental composition were done using X-Ray Diffraction and Field Emission Scanning Electron Microscope with EDS (Energy Dispersive X-Ray Spectrometer), respectively. It is also characterized to determine heavy metals and functional groups using Atomic Absorption Spectroscopy and Fourier Transform Infrared Spectroscopy techniques for various geo-environmental applications. The nonplastic slag material showed 85–92% sand-size particles and 8–15% silt-size particles. The SiO2 and CaO values were found to be high followed by Al2O3, MgO, and other compounds. Since slag performed similarly to sand, it could be used as an alternative source of sand. © Springer Nature Singapore Pte Ltd. 2020.
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    Benthal sludge stabilization in the river Ganga at Kanpur: Part I - Field observations
    (Kalpana Corporation, 2011) Bhargava, D.S.; Shrihari, S.
    Field observations were conducted at Kanpur to analyze the ration of biochemical oxygen demand (BOD) contributions by benthalsludge to the overlying waters of the river Ganga. This data was later correlated to the data obtained under different conditions of operating and process variables in the laboratory. Observations were made at 3 sections along the river downstream of an outfall discharging partially treated wastewater. The rate of BOD contribution by benthalsludge to the overlying waters was estimated by utilizing the observed values of dissolved oxygen (DO) and BOD and is presented in Part 2 of this paper. The rate of BOD contribution was higher at section A during summer and at section B during winter, throughout the depth of overlying waters. This is because of the higher stabilization of the settled organic matter during summer. In winter, the BOD released gets carried away to the downstream sections. The rate of BOD contributions (expressed as a percentage of the BOD remaining in the top benthalsludge layers) was insignificant during winter. The rate of BOD contribution (expressed as a percentage of the BOD added continuously) was higher at sections closer to the outfall during summer, but higher at section B in winter. Predictive models were developed for the rate of BOD contribution by benthalsludge. The observations in the laboratory were done on a significantly smaller model and the field data differed by an order of magnitude. Models were developed to predict the overall scale factor (OSF) for different field conditions by benthalsludge by using the laboratory models. © 2011 - Kalpana Corporation.
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    Benthalsludge stabilization in the river Ganga at Kanpur - Part 2
    (Kalpana Corporation, 2011) Bhargava, D.S.; Shrihari, S.
    Field observations conducted at Kanpur, to analyze the ration of biochemical oxygen demand (BOD) contributions by benthalsludge to the overlying waters of the river Ganga were presented in Part 1 of this paper. This data was later correlated to the data obtained under different conditions of operating and process variables in the laboratory. Observations were made at 3 sections along the river downstream of an outfall discharging partially treated wastewater. The rate of BOD contribution by benthalsludge to the overlying waters was estimated by utilizing the observed values of dissolved oxygen (DO) and BOD. The rate of BOD contribution was higher at section A during summer and at section B during winter, throughout the depth of overlying waters. This is because of the higher stabilization of the settled organic matter during summer. In winter, the BOD released gets carried away to the downstream sections. The rate of BOD contributions (expressed as a percentage of the BOD remaining in the top benthalsludge layers) was insignificant during winter. The rate of BOD contribution (expressed as a percentage of the BOD added continuously) was higher at sections closer to the out fall during summer, but higher at section B in winter. Predictive models were developed for the rate of BOD contribution by benthalsludge. The observations in the laboratory were done on a significantly smaller model and the field data differed by an order of magnitude. Models were developed to predict the overall scale factor (OSF) for different field conditions by benthalsludge by using the laboratory models. © 2011 - Kalpana Corporation.
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    BOD contribution by benthalsludge deposits Part-1: Effect of sludge characteristics
    (Kalpana Corporation, 2008) Bhargava, D.S.; Shrihari, S.
    Organic matter that settles to their river bottoms is the benthalsludge deposits. Decomposition of benthalsludge deposits in streams affect the overlying waters by removal of the dissolved oxygen (DO) from the overlying waters as well as by the benthos and periphytons in the aerobic top layers of the overlying waters and by the immediate oxygen demand of the reduced substances emanating from the deeper anaerobic layers. Secondly, the benthalsludge deposits can also release organic substances and various nutrients into the overlying waters. The oxygen utilisation rate by the benthalsludge deposits may also depend on the sludge characteristics as well as the stream characteristics. In this first part of the paper, the variations of the total oxygen uptake rate in any one days duration and the rate of BOD contribution by benthalsludge in respect of different sludge characteristic parameters have been correlated and discussed. At the top layers of overlying waters, the rate of BOD contribution manifested an optimum high value at benthalsludge depth of 0.1m, and an optimum low value of initial BOD of benthalsludge top layers of around 475 mg/L. The cumulative oxygen consumption till a particular day, was lower or almost same at greater depths of benthalsludges, and manifested a low value at Kd-b value of 0.035. However, the influence of S b-o seemed to be less. The percent BOD contribution indicating the sludge age, manifested an optimum low at benthalsludge depths of 0.2m, both at the top and bottom most layers of overlying waters. The COC values at the interface showed similar trends as in the top layers of overlying waters. The rate of BOD contributions as well as percent contributions, at the interface showed an increasing trend with the Kd-b values. The rate of BOD contributions at the interface also increased with increasing Sb-o values, but the percent BOD contributions manifested an optimum low value. © 2008 - Kalpana Corporation.
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    BOD contribution by benthalsludge deposits-Part II: Effect of stream characteristics
    (Kalpana Corporation, 2008) Bhargava, D.S.; Shrihari, S.
    Organic matter that settles to the river bottoms is the benthalsludge deposits. Decomposition of benthalsludge deposits in streams affect the overlying waters by removal of the dissolved oxygen (DO) from the overlying waters as well as by the benthos and periphytons in the aerobic top layers of the overlying waters and by the immediate oxygen demand of the reduced substances emanating from the deeper anaerobic layers. Secondly, the benthalsludge deposits can also release organic substances and various nutrients into the overlying waters. The oxygen utilisation rate by the benthalsludge deposits may also depend on the stream characteristics as well as the sludge characteristics. In this second part of the paper, the variations of the total oxygen uptake rate in any one days duration and the rate of BOD contribution in respect of different stream characteristic parameters have been correlated and discussed. The flow rate of overlying waters influenced the BOD contribution rate significantly, both at the top and bottom most layers of overlying waters. The rate of BOD contribution manifested optimum values affected by h/d ratios, at the top layers of overlying waters. Predictive models involving all the sludge and stream characteristic parameters have been developed. © 2008 - Kalpana Corporation.
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    Characterization of spatial variability of vertisol micronutrients by geostatistical techniques in Deccan Plateau of India
    (Springer Science and Business Media Deutschland GmbH, 2020) Vinod, V.; Shetty, A.; Shrihari, S.
    In vertisols, accounting for the spatial variability of micronutrients is important for sustainable agriculture. In this study, the assessment of spatial variability maps is carried out by the geostatistical technique in SpaceStat 4.0®. A total of 68 random soil samples were collected from small-scale agricultural lands from Kalaburagi, Karnataka, India. The chemical analysis for iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) was carried out in microwave plasma-atomic emission spectroscopy. The coefficient of variation (CV) showed different micronutrients variability (CV > 35%). The significant correlation is among Cu with Fe and Mn (r = 0.753 and 0.258, respectively). The Box–Cox transformation converted the raw data to normal distribution efficiently. Spherical semivariogram model defined the spatial structure for all micronutrients. The nugget/sill ratio specifies that the Zn showed strong spatial dependence and rest micronutrients moderate. Ordinary kriging is applied for generating maps. The spatial variability maps exhibited different distribution pattern; maps generated are utilized as initial guidance for site-specific management practices and the amount of fertilizer application rate planned in the vertisols. The obtained range and spatial distribution maps act as the baseline in this region for administration planners. © 2019, Springer Nature Switzerland AG.
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    Determination of water quality deterioration at pilgrimage centre along river Netravathi, Mangalore using WQI Approach
    (Gheorghe Asachi Technical University of Iasi, Romania ccti@tuiasi.ro, 2007) Avvannavar, S.M.; Shrihari, S.
    An attempt has been made to develop Water Quality Index (WQI), using six water quality parameters at riverside stations located in the vicinity of temples of Dakshina Kannada district, Karnataka, South India. Rating curves were drawn based on the tolerance limits of inland waters and health point of view. Bhargava WQI method and Harmonic Mean WQI method were used to find overall WQI along the stretch of the river basin. Five point rating scale was used to classify water quality in each of the study areas. It was found that the water quality of Netravathi varied from Excellent to Marginal range by Bhargava WQI method and Excellent to Poor range by Harmonic Mean WQI method. It was observed that the impact of human activity was severe on most of the parameters. The MPN values exceeded the tolerable limits at almost all the stations. It was observed that the main cause of deterioration in water quality was due to the lack of proper sanitation, unprotected river sites and high anthropogenic activities. © 2007, Gheorghe Asachi Technical University of Iasi, Romania. All rights reserved.
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    Development of Simulation Model for Leachate Migration near Vamanjoor Landfill and Treatment of Leachate by Nanoparticles
    (National Institute of Technology Karnataka, Surathkal, 2021) Anand, Divya.; Shrihari, S.; H, Ramesh.
    The impact of leachate from landfill on groundwater has paid a lot of global attention because of its devastating environmental significance. The outputs from landfill induce heavy impacts or risks to the environment forcing the concerned authorities to impose more strict constraints and hence leachate is to be treated before it migrates to the neighboring environment. The Mangaluru City Corporation is collecting the waste on a daily basis and dumping it into a landfill at Vamanjoor located nearly 8.5 km from city centre. The landfill has got a bottom liner, but the drainage to collect leachate is not fully functional. Hence all the untreated leachate formed at the bottom, finds its trails into the neighbouring environment polluting the underlying aquifer. The water sample from observation wells were analysed and results shows that the wells located in 1 km around the landfill are contaminated with the landfill as point source from where contaminants are continuously injected. The leachate collected from landfill was analyzed in the laboratory for various physico-chemical parameters and were compared to the Standards of disposal for Indian standards for surface water IS 2296-1982. It showed that most of the parameters exceeded specified standard for the disposal of waste. Since the composition of the on-site leachate changes every day, in order to maintain repeatable composition, synthetic leachate was prepared in the laboratory. The nano iron was synthesized in the laboratory and characterized using Scanning Electron Microscope. The removal efficiency of chemical oxygen demand (COD) from synthetic leachate using nano iron was studied. For analyzing significant factors which favors the reaction such as pH, initial concentration, optimum concentration of adsorbent to be added, batch experiments were conducted using nano iron with and without starch coating. Batch experiments proved that pH of solution was an important parameter while kinetics coefficients were directly related to pH with correlation coefficients R2> 0.90. The nano iron dosage of 2 mg/l enhances removal efficiency of COD beyond that dosage the effluent will have traces of iron beyond the limit which is undesirable. Based on the removal efficiency which is around 60%, optimum conditions were adopted for continuous fixed-bed study. In a perspex column the nano iron coated with starch is sandwiched between ii untreated natural lateritic soil and the synthetic leachate was allowed to pass through it. The removal efficiency was obtained by comparing COD of influent and COD of effluent. A comparison of batch and column reactor has been done where continuous fixed-bed column was found to be more effective in removal of COD with removal efficiency of 68% in the remediation of leachate which may be due to the adsorption by laterite soil. Evaluation of Freundlich, Langmuir and D–R isotherm models were done. The kinetics of the experiments shows that it follows pseudo first order reaction kinetics. Because of its high removal efficiency, nano iron coated with starch has been taken as an effective remedial agent in treatment of leachate. As it showed better removal efficiency during continuous fixed-bed column studies, it can be used as adsorbent in permeable reactive barriers. Permanent reactive barriers are specially designed reactive zone which extends beneath water table which intercepts and degrade the contaminants in groundwater. The current study focuses on determination of extent of groundwater contamination on a typical tropical coastal aquifer due to a landfill located at Vamanjoor in Dakshina Kannada district, India. MODFLOW which is a standard and popular flow model was used to simulate groundwater flow and MT3DMS was used for simulating contaminant transport because of its ability to model various complexes such as advection, dispersion and chemical reaction involved in the solute transport. The aquifer considered is a shallow, unconfined one with laterite soil which gets good rains during monsoon and will be dry during rest of the year. The adsorption by laterite soil has been considered. The specific yield and transmissivity were estimated to be 7.85% and 213 m2/day respectively. After calibrating successfully with Nash–Sutcliffe efficiency 0.8, horizontal hydraulic conductivity was set as 7m/day. Validation of model was then done with the field data and is applied for forecasting the spread of contaminant for anticipated future scenarios. The results show that in spite of retardation offered by lateritic soil, contaminant trail is expanding with a velocity of 0.15 m/day in downstream direction. The solute transport model MT3DMS was successfully applied to simulate the contaminant transport of the study area. Since MT3DMS model involves the model structure involved in MODFLOW, the model domain was not altered. The model was iii calibrated and validated with reasonable precision (correlation coefficient R2> 0.7) which shows that the model performance is good. The simulated results show that the contaminant has spread for a distance of 1 km radius around the landfill which is in accordance with the actual value of the water quality analysis of observation wells. The model after calibration and validation is applied for the evaluation of general regional impact on the groundwater system for future scenarios. The study revealed that the contamination has spread for a distance of nearly 1 km from the landfill and plume is expanding at a rate of 0.15 m /day. By 15 years the plume will reach a distance of 1.8 km from the landfill. If permanent reactive barrier is installed the expansion of plume can prevented and the pollutant at the observation well located at 1 km from landfill can be reduced less than 400 mg /l. Hence installation of permeable reactive barrier with nano iron can be taken as a remedial alternative in order to control groundwater pollution due to landfill leachate.
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    E-waste management
    (Gheorghe Asachi Technical University of Iasi, Romania ccti@tuiasi.ro, 2007) Avvannavar, S.M.; Shrihari, S.
    E-waste is a new term coined in the market of hazardous substances. It has taken a new bourgeoning route since the boom of Information Technology (IT). The problems regarding the transportation, handling and dispose have to be tackled at the earliest as it might cause detrimental effects on environment. Presently in India there is no distinct and lucid regulation(s) regarding e-waste management. There should one stop solution! In the present paper, some of the Technical and E-Management Strategies that can be implemented by adopting 4 R’s policy-reduce, recovery, recycle and reuse are discussed. © 2007, Gheorghe Asachi Technical University of Iasi, Romania. All rights reserved.
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    Effect of media characteristics on performance of upflow aerobic biofilters
    (2008) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.
    Laboratory studies were conducted to assess the influence of media related factors such as porosity, pore size, particle size and specific surface area on the performance of upflow aerobic biofilters (ABFs). Three simple models of 8 litre capacity upflow submerged ABFs packed with support media of size 40 mm, 20 mm and 10 mm respectively were installed. The hydraulic retention time (HRT) was maintained as 12 hours. The study was carried out for a period of 90 days. The reactor performance indicated that the aerobic biofilter (ABF-3), associated with media of lowest porosity, pore size, particle size and highest specific surface area, demonstrating the highest BOD and COD removal efficiency of 93.32 % and 85.01 % respectively.
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    Effect of pH on the geotechnical properties of laterite
    (2006) Sunil, B.M.; Nayak, S.; Shrihari, S.
    Environmental Geotechnology has emerged as an interdisciplinary science, aiming and forecasting, analyzing and solving the geotechnical problems involving the influence of environmental factors. Lateritic soil of west coast region of India was studied to investigate the effect of soaking on the engineering properties and chemical characteristics of soil, soaked in different pH solutions (pH = 5.0, pH = 7.0, pH = 8.0). 12 N hydrochloric acid and 15 M ammonia solution were used to monitor the pH of the solution for about ninety days. Results showed that the pH of the solution has strong influence on the chemical characteristics of lateritic soil. The engineering properties of soil are altered when compared with the initial characteristics of the soil. The reason for this observed behavior of the soil is addressed in this paper. © 2006 Elsevier B.V. All rights reserved.
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    Effect of wastewaters on the geo-technical properties of laterite
    (2005) Sunil, B.M.; Shrihari, S.
    Soil contamination arises from variety of sources, which include acid rain, hazardous liquid and solid waste from industries, animal waste, salt-water intrusion, etc. Literature relevant to the soil-pollutant interaction reveals that soil properties and behaviour is influenced and altered due to contamination by pollutant. The soil pollutant interaction depends on various factors such as nature and chemical composition of soil, dielectric constant of pore fluid, organic matter etc. Sulphur dioxide and oxides of nitrogen are the two most important parameters responsible for acid rain. Atmospheric pollution has resulted in the precipitation having pH less than 5.6 disturbing the nature's delicate balance and also contamination of soil. The soil and ground water contamination will result in Socio-economic and environmental impact. Several studies by various researchers have highlighted the influence of physico-chemical factors on the engineering properties of soil. The alteration of characteristic properties of the soil in the vicinity of industrial plants occurs mainly as a result of their pollution. Literature review on the effect of acid rain on soils indicated that the pH value of soils generally decreased with continuous infiltration. The major soil chemical parameters affecting the contaminant partitioning are hydrogen ion concentration in the soil, which influences all chemical reactions and biological activities. Laterites and lateritic soil have a very important place in Civil Engineering activities in India, especially in the South and Central parts. They form a good foundation material and are composed essentially of hydrated aluminium and iron oxides. In this paper, the results of an investigation on the effect of pH on the characteristic properties of laterite soil procured from the quarry near Mangalore, located on the western coast of south India, has been discussed. The effect of pH on the characteristic properties of laterite was studied under different pH conditions (i.e. pH =5.0, pH=7.0, pH=8.0). The pH of water in which the laterite blocks were soaked (up to ninety days) was maintained using buffers. The important properties considered for the study are: compressive strength of laterite blocks, Atterbeig limits, shear strength properties and chemical characteristics of laterite soil (pH, conductivity, alkalinity, hardness, chloride, sulphate and ammonia nitrogen). From the investigation it is observed that the engineering properties and chemical characteristics of laterite soil are altered in all the three pH conditions (pH=5.0, pH=7.0, pH=8.0). The compressive strength of laterite blocks reduced under all the pH conditio is and considerable reduction in strength was observed when the pH of water was maintained as 5.0. The pH of adjoining water body has remarkable influence on the pH of soil. Accordingly when the pH of water was low (p -1=5.0), the corresponding pH of soil decreased from its initial value. Similarly soil pH increased when the pH of water was maintained as 8.0 for soaking up to ninety days. The various other effects on the engineering behaxiour and chemical characteristics of laterite are noted and discussed in the present work.
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    Effect of wastewaters on the geo-technical properties of laterite
    (2005) Sunil, B.M.; Shrihari, S.
    Soil contamination arises from variety of sources, which include acid rain, hazardous liquid and solid waste from industries, animal waste, salt-water intrusion, etc. Literature relevant to the soil-pollutant interaction reveals that soil properties and behaviour is influenced and altered due to contamination by pollutant. The soil pollutant interaction depends on various factors such as nature and chemical composition of soil, dielectric constant of pore fluid, organic matter etc. Sulphur dioxide and oxides of nitrogen are the two most important parameters responsible for acid rain. Atmospheric pollution has resulted in the precipitation having pH less than 5.6 disturbing the nature's delicate balance and also contamination of soil. The soil and ground water contamination will result in Socio-economic and environmental impact. Several studies by various researchers have highlighted the influence of physico-chemical factors on the engineering properties of soil. The alteration of characteristic properties of the soil in the vicinity of industrial plants occurs mainly as a result of their pollution. Literature review on the effect of acid rain on soils indicated that the pH value of soils generally decreased with continuous infiltration. The major soil chemical parameters affecting the contaminant partitioning are hydrogen ion concentration in the soil, which influences all chemical reactions and biological activities. Laterites and lateritic soil have a very important place in Civil Engineering activities in India, especially in the South and Central parts. They form a good foundation material and are composed essentially of hydrated aluminium and iron oxides. In this paper, the results of an investigation on the effect of pH on the characteristic properties of laterite soil procured from the quarry near Mangalore, located on the western coast of south India, has been discussed. The effect of pH on the characteristic properties of laterite was studied under different pH conditions (i.e. pH =5.0, pH=7.0, pH=8.0). The pH of water in which the laterite blocks were soaked (up to ninety days) was maintained using buffers. The important properties considered for the study are: compressive strength of laterite blocks, Atterbeig limits, shear strength properties and chemical characteristics of laterite soil (pH, conductivity, alkalinity, hardness, chloride, sulphate and ammonia nitrogen). From the investigation it is observed that the engineering properties and chemical characteristics of laterite soil are altered in all the three pH conditions (pH=5.0, pH=7.0, pH=8.0). The compressive strength of laterite blocks reduced under all the pH conditio is and considerable reduction in strength was observed when the pH of water was maintained as 5.0. The pH of adjoining water body has remarkable influence on the pH of soil. Accordingly when the pH of water was low (p -1=5.0), the corresponding pH of soil decreased from its initial value. Similarly soil pH increased when the pH of water was maintained as 8.0 for soaking up to ninety days. The various other effects on the engineering behaxiour and chemical characteristics of laterite are noted and discussed in the present work.
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    Equilibrium and Kinetic Studies of Hexavalent Chromium Removal Using A Novel Biosorbent: Ruellia Patula Jacq
    (Springer Verlag, 2017) Saranya, N.; Nakkeeran, E.; Shrihari, S.; Selvaraju, N.
    The present work utilized Ruellia patula Jacq leaves as biosorbent for hexavalent chromium removal. Sulfuric acid modification was done and checked for enhanced biosorption capacity. Electron microscopy–energy-dispersive X-ray spectroscopy, Fourier transform infrared spectrometry, elemental analysis were performed for characterization of biosorbents. Batch experiments were conducted to optimize contact time, solution pH, initial Cr(VI) concentration, biosorbent dose, agitation speed and temperature for maximum Cr(VI) removal. Also, the study attempted to show polyphenols present in the biosorbent reduce Cr(VI) through adsorption. Equilibrium data were analyzed using Langmuir, Freundlich and Dubinin–Radushkevich isotherms. Monolayer adsorption capacities of raw and acid-modified biosorbents were found to be 37.03 and 62.50 mg/g, respectively. Pseudo-second-order kinetic model suited well than other models like pseudo-first-order and intraparticle diffusion models examined. Determination of ? H?, ? S? and ? G? from thermodynamic studies showed that the biosorption is exothermic, stable and thermodynamically feasible. Desorption studies using NaOH as desorbing agent showed considerable performances up to three cycles. These findings revealed that Ruelliapatula leaves serve as potent biosorbent for the removal of hexavalent chromium from aqueous solutions. © 2017, King Fahd University of Petroleum & Minerals.
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    Estimation and Mapping of Vertisols Soil Nutrients by Geostatistics and Remote Sensing Approach
    (National Institute of Technology Karnataka, Surathkal, 2022) Vinod,Tamburi; Shrihari, S.; Amba,Shetty
    he status of soil fertility is a concern, especially in the Deccan plateau vertisols of India. Vertisols are productive if they are managed well. Understanding the spatial variability of soil nutrients is necessary for agriculture to maintain sustainability. The objective of the present study is to characterize the status of soil nutrients, spatial variability of selected soil nutrients, and the estimation of the presence of these soil nutrients by spaceborne Hyperion data in scattered small-size fields of Gulbarga taluk, northern Karnataka, India. This region is known as the "pigeon pea vessel" of the state. The geostatistical analysis is carried out in SpaceStat 4.0® to find the spatial variability of all the selected nutrients. The coefficient of variation monitors the variation in the nutrients of the soil. The variogram analysis has shown that all the selected nutrients are the best fit for the spherical model except nitrogen, organic carbon, and phosphorus. The nugget/sill ratio is utilized to know the spatial dependence of soil nutrients. Using the best fit model, surface maps are generated by the ordinary kriging method. The estimation of soil nutrients from Hyperion data with statistical regression is measured as an alternative technique. The spectral information of the visible near infrared and short wave infrared range (400-2500 nm) is utilized to characterize soil nutrients. The potential of the Hyperion data has not yet been exploited completely due to noisy atmospheric components in spectral signatures especially in fields of smaller size. Sixty-eight random topsoil samples were collected from small farms, which are less than two acres in size. The systematic sampling of soil was conducted in the month (third week) of November 2016. This duration is also synchronized with the passage of the Hyperion satellite above the study area. The atmospheric (FLASSH) and geometric corrections is carried out and then the spectral reflectances are extracted. The PLS_Toolbox is used for filtering (Savitzky Golay), and the Partial Least square regression (PLSR) technique is applied for the estimation of soil nutrients by Hyperion data. The variable importance in projection (VIP) is identified, which reduces the non-significant wavelengths for the PLSR model. Two indices are ii used to assess the prediction accuracy, Coefficient of determination (R2), and root mean square error (RMSE). From analysis of soil nutrients, it is observed that the spatial variability maps exhibited a heterogeneous pattern of soil nutrients because of individual farming methods. The spatial variability maps are used as initial regulation by policymakers for site nutrient management, including fertilization in vertisols. This is essential for sustainable management of the fields, which are aimed at increasing the productivity of the crops; low productivity vertisols are to be used in cultivation on a global scale due to the current shortage of food supplies and agricultural resources land. The utilization of Hyperion data and PLSR technique showed that it has the low to moderate potential to estimate certain vertisols nutrients such as iron (R2=0.40), potassium (R2=0.45), and Copper (R2=0.41), and moderate estimation for nitrogen (R2=0.54) even though vertisols have less reflectance values compared to other soil types. The vertisols of India exhibit low reflectance, which are deficient in humus, nitrogen, phosphorus, and potassium due to low permeability and moisture stress throughout the drought. Hence the presence of soluble nutrients concentration is low compared to other soil. Generally, the white color contributes to higher reflectance in all wavelengths, so the grey-brown color is natural in the vertisols fields and along with less organic matter, which leads to the low reflectance. Hyperion data can be inventively utilized to estimate vertisols soil nutrients with reasonable accuracy in heterogeneous and small size fields.
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    Estimation of Vertisols Soil Nutrients by Hyperion Satellite Data: Case Study in Deccan Plateau of India
    (Springer, 2022) Vinod, N.T.; Shetty, A.; Shrihari, S.
    Soil nutrients are essential for agricultural purpose. There are efforts for estimation of topsoil properties using visible and near infrared reflectance (VIS–NIR) of Hyperion satellite. Notwithstanding this, there should be more research on variety of soils and fields of practicable size especially in the Indian context, necessary for using this on a practical basis. To bridge this gap, estimation of selected soil nutrients (nitrogen (N), potassium (K), copper (Cu) and iron (Fe)) from small sized and randomly scattered vertisols fields taken up in Deccan plateau of India using Hyperion satellite data. The nutrient index (NI) for Fe was estimated to be higher (NI = 2.76) than other nutrients in the study area, which influences the spectral behavior. The pretreatment of Hyperion reflectance data by Savitzky-Golay filter (window size 15, second-order derivative) and partial least square regression (PLSR) analysis resulted in low to moderate estimations of soil nutrients. The variable importance projection (VIP) for each soil nutrient has been estimated. The important wavelengths were identified in the mid infrared region for nitrogen. For Potassium, the wavelengths were identified in the visible, near infrared and the mid infrared regions. The near infrared and midinfrared region for iron. Lastly for Cu, in the green region and mid infrared region were identified. The prediction accuracy for N, K, Fe, and Cu were estimated to be medium, with coefficients of determination values as 54%, 45%, 40%, and 41%, respectively. The vertisols in the study region demonstrated low reflectance that is deficient in humus, due to low permeability and moisture stress throughout the drought. Hence the presence of soluble nutrients concentration is low compared to other soils. In this study considering the results of R2, the iron has good prediction, then other soil properties. Thus, the present research implied that, Hyperion satellite data provides moderate potential to estimate the Indian vertisols soil nutrients. © 2022, Indian Society of Remote Sensing.