Journal Articles
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Item Application of life cycle assessment in municipal solid waste management: A worldwide critical review(Elsevier Ltd, 2019) Khandelwal, H.; Dhar, H.; Thalla, A.K.; Kumar, S.The whopping increase in solid waste generation all over the world calls for the development of waste management strategies for a sustainable environment. By the quantification of environmental impacts, life cycle assessment (LCA) tool can help in answering the call. It evaluates the environmental performance of municipal solid waste management (MSWM) system which helps decision-maker in selecting the best management strategy with minimum impacts on the environment. But, up to what extent the LCA methodology can be applied to MSWM systems? To address this question, the present study analyzed the 153 LCA studies published till date since 2013 all over the world. The present study analyzed the time evolution, geographical distribution, and methodology applied in LCA studies. It summarized the use of the functional unit, LCA model, Life Cycle Impact Assessment (LCIA) method, MSWM options, and the critical findings of the selected LCAs, along with MSW composition, income group, and the gaps in the application of the studies. For evaluating the dependence of publication of studies and country's economic condition, the countries in which LCA studies were conducted are classified into four groups on the basis of income level viz., lower income, lower middle income, upper middle income, and higher income countries. In terms of technological coverage, 1 ton of MSW was the most used functional unit. SimaPro was the majorly used LCA model while 56 of the total studies didn't mention about the use of LCA model, only 66 of the total studies included sensitivity analysis in the assessment. Integrated solid waste management was found to be the most preferred waste management option. Also, a very limited number of studies have included life cycle costing and social aspects of MSWM system. The results indicated that the majority of the LCA studies are based in Europe and Asia. Shockingly, 178 out of the total countries in the world have not published a single LCA study on MSWM since 2013. Also, it was found that the effect of increasing Gross Domestic Product (GDP) on the publication of LCA studies is irrelevant, possible reasons being the lack of data, time and economic constraints. Establishment of environment-friendly policies and initiatives by the Government along with the participation of public, non-government and private organizations through training courses and seminars might help in improving the LCA applicability in the field of MSWM. © 2018 Elsevier LtdItem 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.Item 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.Item Artificial neural network based modeling to evaluate methane yield from biogas in a laboratory-scale anaerobic bioreactor(Elsevier Ltd, 2016) Nair, V.V.; Dhar, H.; Kumar, S.; Thalla, A.K.; Mukherjee, S.; Wong, J.W.C.The performance of a laboratory-scale anaerobic bioreactor was investigated in the present study to determine methane (CH4) content in biogas yield from digestion of organic fraction of municipal solid waste (OFMSW). OFMSW consists of food waste, vegetable waste and yard trimming. An organic loading between 40 and 120 kg VS/m3 was applied in different runs of the bioreactor. The study was aimed to focus on the effects of various factors, such as pH, moisture content (MC), total volatile solids (TVS), volatile fatty acids (VFAs), and CH4 fraction on biogas production. OFMSW witnessed high CH4 yield as 346.65 L CH4/kg VS added. A target of 60–70% of CH4 fraction in biogas was set as an optimized condition. The experimental results were statistically optimized by application of ANN model using free forward back propagation in MATLAB environment. © 2016 Elsevier LtdItem 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 LtdItem Ranking and comparison of draw solutes in a forward osmosis process(Techno Press technop2@chollian.net, 2017) Girijan, G.; Thalla, A.K.Forward osmosis (FO) is an emerging technology which can possibly make the desalination process more cost and energy efficient. One of the major factors impeding its growth is the lack of an appropriate draw solute. The present study deals with the identification of potential draw solutes, and rank them. The comparison was carried out among ten draw solutes on the basis of four main parameters namely; water flux, reverse salt diffusion, flux recovery and cost. Each draw solute was given three 24 hour runs; corresponding to three different concentrations; and their flux and reverse salt diffusion values were calculated. A fresh membrane was used every time except for the fourth time which was the flux recovery experiment conducted for the lowest concentration and the change of flux and reverse salt diffusion values from the initial run was noted. The organic solutes inspected were urea and tartaric acid which showed appreciable values in other parameters viz. reverse salt diffusion, flux recovery and cost although they generated a lower flux. They ranked 5th and 8th respectively. All the experimented draw solutes were ranked based on their values corresponding to each of the four main parameters chosen for comparison and Ammonium sulfate was found to be the best draw solute. © 2017 Techno-Press, Ltd.Item Artificial intelligence models for predicting the performance of biological wastewater treatment plant in the removal of Kjeldahl Nitrogen from wastewater(Springer Verlag, 2017) Manu, D.S.; Thalla, A.K.The current work demonstrates the support vector machine (SVM) and adaptive neuro-fuzzy inference system (ANFIS) modeling to assess the removal efficiency of Kjeldahl Nitrogen of a full-scale aerobic biological wastewater treatment plant. The influent variables such as pH, chemical oxygen demand, total solids (TS), free ammonia, ammonia nitrogen and Kjeldahl Nitrogen are used as input variables during modeling. Model development focused on postulating an adaptive, functional, real-time and alternative approach for modeling the removal efficiency of Kjeldahl Nitrogen. The input variables used for modeling were daily time series data recorded at wastewater treatment plant (WWTP) located in Mangalore during the period June 2014–September 2014. The performance of ANFIS model developed using Gbell and trapezoidal membership functions (MFs) and SVM are assessed using different statistical indices like root mean square error, correlation coefficients (CC) and Nash Sutcliff error (NSE). The errors related to the prediction of effluent Kjeldahl Nitrogen concentration by the SVM modeling appeared to be reasonable when compared to that of ANFIS models with Gbell and trapezoidal MF. From the performance evaluation of the developed SVM model, it is observed that the approach is capable to define the inter-relationship between various wastewater quality variables and thus SVM can be potentially applied for evaluating the efficiency of aerobic biological processes in WWTP. © 2017, The Author(s).Item The combined effects of carbon/nitrogen ratio, suspended biomass, hydraulic retention time and dissolved oxygen on nutrient removal in a laboratory-scale anaerobic–anoxic–oxic activated sludge biofilm reactor(IWA Publishing, 2018) Manu, D.S.; Thalla, A.K.The current trend in sustainable development deals mainly with environmental management. There is a need for economically affordable, advanced treatment methods for the proper treatment and management of domestic wastewater containing excess nutrients (such as nitrogen and phosphorus) which can cause eutrophication. The reduction of the excess nutrient content of wastewater by appropriate technology is of much concern to the environmentalist. In the current study, a novel integrated anaerobic–anoxic–oxic activated sludge biofilm (A2O-AS-biofilm) reactor was designed and operated to improve the biological nutrient removal by varying reactor operating conditions such as carbon to nitrogen (C/N) ratio, suspended biomass, hydraulic retention time (HRT) and dissolved oxygen (DO). Based on various trials, it was seen that the A2O-AS-biofilm reactor achieved good removal efficiencies with regard to chemical oxygen demand (95.5%), total phosphorus (93.1%), ammonia nitrogen concentration (NH4þ-N) (98%) and total nitrogen (80%) when the reactor was maintained at C/N ratio of 4, suspended biomass of 3 to 3.5 g/L, HRT of 10 h, and DO of 1.5 to 2.5 mg/L. Scanning electron microscopy (SEM) of suspended and attached biofilm showed a dense structure of coccus and bacillus bacteria with the diameter ranging from 0.3 to 1.2 ?m. The Fourier transform infrared (FTIR) spectroscopy results indicated phosphorylated macromolecules and carbohydrates mix or bind with extracellular proteins in exopolysaccharides. © IWA Publishing 2018.Item Influence of various operating conditions on wastewater treatment in an AS-biofilm reactor and post-treatment using TiO2-based solar/UV photocatalysis(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2019) Manu, D.S.; Thalla, A.K.In the present study, the effect of carbon to nitrogen (C/N) ratio, suspended biomass concentration (X), hydraulic retention time (HRT) and dissolved oxygen (DO) on chemical oxygen demand (COD) and nutrient removal from wastewater was investigated in a lab-scale activated sludge (AS)-biofilm reactor. Furthermore, in order to improve the quality of the treated wastewater, photocatalysis by TiO2 was investigated as a post-treatment technology, using solar and UV irradiations. The AS-biofilm reactor provided a substantial removal efficiency in terms of COD, ammonia nitrogen (NH+4-N), total nitrogen (TN) and total phosphorous when the system was maintained at C/N ratio 6.66, X in the range 2–2.5 g/L, HRT 10 h, DO in the range of 3.5–4.5 mg/L and organic loading rate (OLR) of 0.96 kg COD/m3d during Run 1. Similarly, when the reactor was maintained at C/N ratio 10, X in the range of 3–3.5 g/L, HRT 8 h, DO in the range of 3.5–4.5 mg/L and OLR of 1.8 kg COD/m3d during Run 2. The microstructure of suspended and attached biomass comprised a dense bacterial structure of cocci and bacillus microorganisms. The UV photocatalysis was found to be better than solar photocatalysis during the comparative analysis. The maximum removal efficiencies of COD, most probable number and phosphorous at optimum conditions in the case of UV and solar irradiations were 72%, 95%, 52% and 71%, 99%, 50%, respectively. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.Item 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