Faculty Publications
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Item Aerobic sludge granulation and enhanced dicamba removal efficiency in the presence of AQS redox mediator in a lab-scale anaerobic-aerobic treatment method(Elsevier, 2021) Basappa, M.G.; Manu, B.The biodegrading of dicamba was conducted using the anaerobic-aerobic technique for influent concentrations 60-100 mg/L over 187 days of operation. The reactors were stabilized using starch and acclimated to 40 mg/L of dicamba. Dicamba and starch was fed to the anaerobic reactor. Effluent was collected after a hydraulic retention time of 24 h and analyzed in gas chromatography-high-resolution mass spectrometry to detect the biotransformation products. High concentration of benzoates, esters, and fatty acid groups were detected in the anaerobic reactor. Effluent of anaerobic reactor contained high chemical oxygen demand (COD) concentration 400-750 mg/L, which was then fed to the aerobic reactor. After aerobic posttreatment, the overall dicamba and COD removal obtained were >85 and 92% respectively. The aerobic reactor developed a thick granular biomass of up to 7 mm in size, which indicates the bacterial adaptation and hence attainment of stable reactor performance. © 2021 Elsevier B.V. All rights reserved.Item Fenton's treatment of actual agriculture runoff water containing herbicides(IWA Publishing 12 Caxton Street London SW1H 0QS, 2017) Sangami, S.; Manu, B.This research was to study the efficiency of the Fenton's treatment process for the removal of three herbicides, namely 2,4-dichlorophenoxy acetic acid (2,4-D), ametryn and dicamba from the sugarcane field runoff water. The treatment process was designed with the Taguchi approach by varying the four factors such as H 2 O 2 /COD (1-3.5), H 2 O 2 /Fe 2+ (5-50), pH (2-5) and reaction time (30-240 min) as independent variables. Influence of these parameters on chemical oxygen demand (COD), ametryn, dicamba and 2,4-D removal efficiencies (dependent variables) were investigated by performing signal to noise ratio and other statistical analysis. The optimum conditions were found to be H 2 O 2 /COD: 2.125, H 2 O 2 /Fe 2+ : 27.5, pH: 3.5 and reaction time of 135 min for removal efficiencies of 100% for ametryn, 95.42% for dicamba, 88.2% for 2,4-D and with 75% of overall COD removal efficiencies. However, the percentage contribution of H 2 O 2 /COD ratio was observed to be significant among all four independent variables and were 44.16%, 67.57%, 51.85% and 50.66% for %COD, ametryn, dicamba and 2,4-D removal efficiencies, respectively. The maximum removal of herbicides was observed with the H 2 O 2 dosage of 5.44 mM and Fe 2+ dosage of 0.12 mM at pH 3.5. © IWA Publishing 2017 W.Item Optimization of Fenton’s oxidation of herbicide dicamba in water using response surface methodology(Springer Verlag, 2017) Sangami, S.; Manu, B.In this study Fenton’s oxidation of dicamba in aqueous medium was investigated by using the response surface methodology. The influence of H2O2/COD (A), H2O2/Fe2+ (B), pH (C) and reaction time (D) as independent variables were studied on two responses (COD and dicamba removal efficiency). The dosage of H2O2 (5.35–17.4 mM) and Fe2+ (0.09–2.13 mM) were varied and optimum percentage removal of dicamba of 84.01% with H2O2 and Fe2+ dosage of 11.38 and 0.33 mM respectively. The whole oxidation process was monitored by high performance liquid chromatography (HPLC) along with liquid chromatography/mass spectrometry (LC/MS). It was found that 82% of dicamba was mineralized to oxalic acid, chloride ion, CO2 and H2O, which was confirmed with COD removal of 81.53%. The regression analysis was performed, in which standard deviation (<4%), coefficient of variation (<8), F value (Fisher’s Test) (>2.74), coefficient of correlation (R2 = Radj2) and adequate precision (>12) were in good agreement with model values. Finally, the treatment process was validated by performing the additional experiments. © 2017, The Author(s).Item Bacteriological synthesis of iron hydroxysulfate using an isolated Acidithiobacillus ferrooxidans strain and its application in ametryn degradation by Fenton's oxidation process(Academic Press, 2019) Bhaskar, S.; Manu, B.; Sreenivasa, M.Y.The investigation reports the application of biogenic jarosite, an iron hydroxy sulfate mineral in Fenton's Oxidation process. Ametryn, a herbicide detrimental to aquatic life and also to human is treated by Fenton's oxidation process using synthesized iron mineral, jarosite. The jarosite synthesis was carried out by using an isolated Acidithiobacillus ferrooxidans bacterial strain with ferrous as an iron supplement. The isolated strain was characterized by molecular techniques and biooxidation activity to ferrous to ferric iron was checked. On Fenton's treatment ametryn degradation upto 84.9% and COD removal to the extent of 56.1% was observed within 2 h of treatment and the reaction follows the pseudo first order kinetics with the curve best fit. The slight increase in kinetic rate constant on jarosite loading rate increase from 0.1 g/L to 0.5 g/L with H2O2 dosage of 100 mg/L confirms that jarosite has a catalytic role in the removal of ametryn. Mass spectroscopy analysis of treated synthetic ametryn solution at various intervals reveal the degradation follows dealkylation and hydroxylation pathway with the formation of three major intermediate compounds discussed here. © 2018 Elsevier LtdItem Biological Treatment of 3,6-Dichloro-2-Methoxybenzoic Acid Using Anaerobic-Aerobic Sequential Batch Reactor(Springer Basel info@birkhauser-science.com, 2019) Mahesh, G.B.; Manu, B.A sequential anaerobic-aerobic batch reactor was used to treat 3,6-dichloro-2-methoxybenzoic acid (dicamba) during a long operation period of 340 days in the presence of disodium anthraquinone-2,6-disulphonate (AQS) as redox mediator. The sludge activity was evaluated for different dosages of dicamba over constant hydraulic retention time (HRT), neutral pH (6.5–7.5) and at ambient reactor temperature. Effects of increased dicamba concentration, solids retention time (SRT) and oxidation reduction potential (ORP) on the biodegradation of dicamba was monitored and compared with control reactor containing no dicamba. Results revealed that long operation period, long SRT and ORP were playing important role in the breakdown of dicamba to its transformation products and subsequent removal in the system. The system was capable of degrading the compound completely during long operation period, long SRT and at low ORP in the presence of AQS. Reducing condition in the anaerobic reactor significantly contributed to the treatment process through demethylation, dehalogenation and dechlorination reactions in the presence of different reducing bacteria. The results of GC-HRMS identified the anaerobic transformation products of dicamba as oleic acid (C18H34O2), 9-Octadecenoic acid (Z), 2-hydroxy-1-(hydroxymethyl)ethyl ester (C21H40O4), trans-13-Ocatadecenoic acid (C18H34O2) compounds which were then oxidised in the aerobic reactor. © 2019, Springer Nature Switzerland AG.Item Biodegradation of ametryn and dicamba in a sequential anaerobic-aerobic batch reactor: A case study(IWA Publishing 12 Caxton Street London SW1H 0QS, 2019) Mahesh, G.B.; Manu, B.Agricultural runoff often contains persistent halogenated herbicide compounds like 2-(ethylamino)-4-(isopropylamino)-6-(methylthio)-s-triazine (ametryn) and 3,6-dichloro-2-methoxybenzoic acid (dicamba). These can enter the food chain through drinking water, causing serious effects for people and the environment. A sequential anaerobic reactor followed by an aerobic reactor was operated and investigated for herbicide removal efficiency at constant, three-day, hydraulic retention time (HRT) and organic loading rate (OLR) of 0.2025 kg-COD/m3/d. The effect of the herbicides on anaerobic bacteria was evaluated based on total biogas production and bacterial activity, which indicated that there was no inhibition on the acclimated biomass. The sequential reactor pair removed 72% of ametryn and 78% dicamba, with COD removal efficiencies of 86% and 85% respectively. The different high-performance liquid chromatography (HPLC) peaks indicate that the compounds are biotransformed and this was confirmed by gas chromatograph high resolution mass spectrometry (GC-HRMS). © IWA Publishing 2019.Item Catalytic efficiency of laterite-based FeNPs for the mineralization of mixture of herbicides in water(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2019) Sangami, S.; Manu, B.In this work, low cost, locally available laterite-based iron nanoparticles were synthesized using Tectona Grandis extract (Teak extract) with an average size of 75 nm. The synthesized FeNPs were applied as a heterogeneous Fenton catalyst for the oxidation of mixture herbicides, namely ametryn, dicamba and 2,4-D in water. The FeNPs were characterized for various analytical methods (field emission scanning electron microscopy-X-ray energy-dispersive spectrophotometer, XRD, FTIR and BET) and the effect of different variables (FeNPs dosage, H2O2, pH) was studied using the responses surface methodology. The initial herbicide concentration was considered as 25, 3.5 and 94 mg L?1 for 2,4-D, ametryn and dicamba, respectively, with the COD value of 172 mg L?1. The 100% degradation and mineralization was achieved in 135 min and >85% in 45 min (optimum dosage: FeNPs = 25.29 mg L?1, H2O2= 430 mg L?1 and pH = 5). The degradation kinetics were performed for both pseudo-first order and second order, it was observed that first-order kinetics (R2> 0.85) was well fitted in the treatment process. Recycling of FeNPs in five cycles was performed at optimum conditions and 10–40% of reduction in degradation efficiency was achieved. Finally, the whole treatment process was validated with a contour overlay plot and analysis of variance. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.Item Bioleaching of iron from laterite soil using an isolated Acidithiobacillus ferrooxidans strain and application of leached laterite iron as Fenton’s catalyst in selective herbicide degradation(Public Library of Science, 2021) Bhaskar, S.; Manu, B.; Sreenivasa, M.Y.A novel isolated strain Acidithiobacillus ferrooxidans BMSNITK17 has been investigated for its bioleaching potential from lateritic soil and the results are presented. System conditions like pH, feed mineral particle size, pulp density, temperature, rotor speed influences bioleaching potential of Acidithiobcillus ferrooxidans BMSNITK17 in leaching out iron from laterite soil. Effect of sulfate addition on bioleaching efficiency is studied. The bioleached laterite iron (BLFe’s) on evaluation for its catalytic role in Fenton’s oxidation for the degradation of ametryn and dicamba exhibits 94.24% of ametryn degradation and 92.45% of dicamba degradation efficiency. Fenton’s oxidation performed well with the acidic pH 3. The study confirms the role of Acidithiobacillus ferrooxidans in leaching iron from lateritic ore and the usage of bioleached lateritic iron as catalyst in the Fenton’s Oxidation. © 2021 S et al.