Conference Papers
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Item Machine learning approaches for the estimation of particulate matter (PM2.5) concentration levels: A case study in the Hyderabad City, India(Springer Verlag, 2019) Krishnappa, L.; Devatha, C.P.Particulate matter concentration is one among several variables monitored at regular intervals to calculate air quality indices (AQI) which are intended to help understand the acute and chronic effects of air quality on human health. The fine particulate (PM2.5) samplers installed at pollution monitoring stations continuously monitor the concentration of pollutant in air over time. The specific time-averaged concentration is then estimated from the continuous records. Missing data records in the PM2.5 time series is quite normal, which is attributed by faulty equipment, routine maintenance schedules, or replacement of equipment. When one or more point observations in a time series are missing, it is very essential to estimate or predict the missing values. This study presents the application of machine learning techniques such as support vector regression (SVR), group method of data handling (GMDH) network, and evolutionary adaptive neuro fuzzy inference system to estimate the 24-h average PM2.5 concentration levels at a particular station using PM2.5 concentration levels observed at neighborhood stations as inputs. The performance of these models are evaluated in terms of widely used statistical metrics such as centered root mean square difference (CRMSD), normalized Nash–Sutcliffe efficiency (NNSE), and correlation coefficient (R). The findings of the study reveal that the GMDH model provided reasonably accurate estimates of daily PM2.5 levels. © Springer Nature Singapore Pte Ltd. 2019.Item Phosphorus recovery as induced struvite from deep dewatered liquors using magnesium chloride as a magnesium source(Institute of Physics Publishing helen.craven@iop.org, 2019) Rashmi, H.R.; Devatha, C.P.The phosphorus recoveries in municipal wastewater treatment plants (WWTPs) are in much demand as the price of phosphate rock are increased from the last decade. Due to the increase in pollution levels of the sewage sludge, it is difficult to use sewage sludge directly as fertilizers in agricultural fields. The present study aimed to work on the recovery of phosphorus from the deep dewatered liquors in a laboratory, batch test mode. Experiments were conducted to identify the initial characteristics of sludge and for recovery analysis, by varying the phosphorus and Magnesium (Mg:P) molar ratio. Characterization studies were performed by SEM and FTIR for confirmation of struvite formation. Results obtained revealed that recovery is 94% of the incoming phosphorus. © 2019 IOP Publishing Ltd. All rights reserved.Item Impact On Leaching Behaviour Of Toxic Metals In Ferrochrome Ash With Varying Ph Levels(American Institute of Physics Inc., 2022) Krishnamurthy, M.P.; Devatha, C.P.In the current investigation, leaching behaviour of cobalt (Co), copper (Cu), iron (Fe), zinc (Zn), calcium (Ca), arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), nickel (Ni), lead (Pb) and selenium (Se) from fresh and aged Ferrochrome Ash (FCA) samples were studied under various pH conditions (3-11). Results reveal that most of the elements follow oxyanionic leaching pattern where increase in pH increases the effluent concentration of elements. Leached As, Pb, Hg, Ni and Fe reached peak concentration at alkaline phases. Cd, Cr and Zn followed cationic leaching pattern where increase in pH decreases the concentration. Any specified pattern of leaching is not followed by Ca, Se, Co and Cu. Results of leaching test reveal that the high concentration of chromium leaching was found to be 156.18 and 155 mg/L, concentration of arsenic 13.46 and 12.89 mg/L, concentration of mercury 10.23 and 10.4 mg/L and lead concentration of 6.58 and 6.72 mg/L for fresh and aged FCA ashes respectively. Hence Cr, As, Hg and Pb are identified as significant hazardous pollutants and must not be discharged without being solidified/stabilized. Leached element concentration was not affected significantly by aging of the FCA. © 2022 American Institute of Physics Inc.. All rights reserved.Item Entrapment of Nickel in Ferrochrome Ash by Native Lysinibacilus sp Bacteria(Avestia Publishing, 2023) Kothuri, M.; Devatha, C.P.Nickel contamination in water is a significant environmental concern and causes several health effects such as allergies, cardiovascular diseases, and cancers in human beings. Ferrochrome ash is a fine dust generated as the waste from steel industry and pollutes the flow-through water by leaching nickel present in it. By providing a pre-disposal treatment of microbial induced calcite precipitation (MICP) to ferrochrome ash, the nickel leaching can be substantially reduced. Bacteria secrete the urease enzyme that decides the rate of urea hydrolysis reaction and they are the nucleation sites for the precipitation of calcium carbonate in calcium rich environment. During MICP, calcium carbonate entraps the nickel present in the ash. As a result, the nickel cannot escape the ash matrix and hence do not pollute the contacting water. This was confirmed by the atomic absorption spectrophotometric analysis (AAS) on leachates from treated and untreated ash. The analysis resulted in less nickel content from treated ash with highest treatment efficiency of 98% at LS 100. Results from SEM, FTIR, XRD, and TG implied that calcium carbonate developed in the ash due to MICP. © 2023, Avestia Publishing. All rights reserved.Item Numerical Simulation of Contaminant Transport in Subsurface Soil Using MODFLOW Software(Springer Nature, 2023) Bincy, B.; Devatha, C.P.; Thalla, A.K.Groundwater demand is increasing rapidly due to the growing contamination of surface water resources in the present scenario. Surface water bodies like the ocean, wetlands, and estuaries always influence it. Inevitably, groundwater is also facing a major threat of contamination. It is not possible to directly observe the subsurface groundwater flow processes. Industrial discharge is a major source of pollutants in the study area. Hence, it is imperative to study the dynamics of groundwater and contamination characteristics in this area. A geographic information system (GIS) integrated with the MODFLOW is adopted to achieve the purpose. Major input parameters include water quality and water level data collected from 2016 to 2020. The model uses site soil characteristics, flow parameters, and recharge data to match the field conditions. The results project the present status of water availability in the aquifer system and the level of contamination in the study area. The simulated water levels correlate with the observed values with an error estimate (root mean square error) of 0.95. The results of this study can be utilized to suggest the predictive measure to be adopted to restore the water quality and quantity aspect in the study area. Further, it can be extended to predict treatment measures to reduce future contamination. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.Item Geo-Morphological Assessment in the Upper Reaches of Krishna River (India) Using Multi-temporal Satellite Data During 1991–2021(Springer Science and Business Media Deutschland GmbH, 2024) Choudhary, P.; Azhoni, A.; Devatha, C.P.Rivers have historically served as the birthplace of human civilization. The study of channel planform and geo-morphological characteristics is of utmost importance in investigating the effects of climate change and alterations in land use on the overall well-being of rivers. This study examines the temporal variations in the geo-morphological characteristics of the upper reaches of Krishna River during three decades (1991–2021). Spatial data is obtained from several satellite missions and afterward processed using Remote Sensing and Geographic Information Systems (GIS) to assess alterations in the active river channel's extent, erosion, and accretion areas and the sinuosity index. The river channel has been segmented into seven sub-reaches, and it has been observed that some sections of the bank line require prompt attention from the relevant authorities to carry out bank protection measures. The findings indicate that the left bank exhibits a greater tendency towards erosion and shifting compared to the right bank. Additionally, the river has undergone geo-morphological alterations due to the construction of hydraulic structures and the occurrence of numerous flood events within the basin. The sinuosity index of the river provides evidence of its meandering nature. This study offers valuable insights into the dynamic behavior of the Upper Krishna River, hence providing useful information for authorities and decision-makers involved in river training initiatives and future development projects. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Statistical Modeling of Bacterial Statistical Modeling of Bacterial Culture Medium Composition Affecting Mineralization in Ferrochrome Ash(Springer Nature, 2024) Kothuri, M.; Devatha, C.P.Biomineralization is expected as an effective treatment technology to stabilize ferrochrome ash. It operates based on urea hydrolysis principle, and it requires an efficient medium for good bacterial growth and urease activity. An optimal medium is an ideal combination of protein, vitamin, and carbon source in the feed for bacteria. The objective of the current study is to optimize the medium and analyze the significance of its components on bacterial growth and urea hydrolysis. A central composite design (CCD) was developed with 20 experiments with different quantities of soybean (protein), yeast extract (vitamin), and dextrose (carbon) in the medium. Optical density at 600 nm and urease activity were determined after 12 h from inoculation and analyzed using response surface methodology (RSM) in Design-Expert software. Maximum urease activity of 27.83 mM of urea hydrolyzed/min and a maximum optical density of 1.92 were observed with the standard runs 4 and 10, respectively. According to the findings of the current study, the dosages of vitamin source and protein source were significantly affecting urease activity and optical density. It is inferred that the most crucial factor for optical density in the medium is protein dosage, and urease activity is vitamin dosage. Both bacterial growth and urea hydrolysis were minimally affected by the carbon dosage, suggesting that regulating the protein and vitamin doses, combined with a nominal carbon dose, results in an optimal growth medium for the biomineralization in ferrochrome ash. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.