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 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 Synthesis of plant-based biogenic jarosite nanoparticles using Azadirachta indica and Eucalyptus gunni leaf extracts and its application in Fenton degradation of dicamba(Editorial Office of Water Science and Engineering, 2024) Bhaskar, S.; Manu, B.; Sreenivasa, M.Y.; Manoj, A.Bio-jarosite, an iron mineral synthesized biologically using bacteria, is a substitute for iron catalysts in the Fenton oxidation of organic pollutants. Iron nanocatalysts have been widely used as Fenton catalysts because they have a larger surface area than ordinary catalysts, are highly recyclable, and can be treated efficiently. This study aimed to explore the catalytic properties of bio-jarosite iron nanoparticles synthesized with green methods using two distinct plant species: Azadirachta indica and Eucalyptus gunni. The focus was on the degradation of dicamba via Fenton oxidation. The synthesized nanoparticles exhibited different particle size, shape, surface area, and chemical composition characteristics. Both particles were effective in removing dicamba, with removal efficiencies of 96.8% for A. indica bio-jarosite iron nanoparticles (ABFeNPs) and 93.0% for E. gunni bio-jarosite iron nanoparticles (EBFeNPs) within 120 min of treatment. Increasing the catalyst dosage by 0.1 g/L resulted in 7.6% and 43.0% increases in the dicamba removal efficiency for EBFeNPs and ABFeNPs with rate constants of 0.025 min−1 and 0.023 min−1, respectively, confirming their catalytic roles. Additionally, the high efficiency of both catalysts was demonstrated through five consecutive cycles of linear pseudo-first-order Fenton oxidation reactions. © 2023 Hohai UniversityItem Fenton and Sono-Fenton degradation of selective herbicides in water using bioleached Fe-Cu bimetallic nanoparticles (BFe-CuNPs)(Springer Science and Business Media Deutschland GmbH, 2025) Bhaskar, S.; Ashraf, S.; Apoorva, K.V.Bimetallic nanoparticles offer an innovative solution for treating water and wastewater systems using a heterogeneous Fenton-like process. This study investigates the synthesis of iron-copper bimetallic nanoparticles using bioleached iron and copper as precursors and evaluates their performance in the degradation of selective herbicides ametryn and dicamba by Fenton’s oxidation and Sono-Fenton’s oxidation. Bioleaching experiments were conducted separately for iron and copper leaching from laterite ore and chalcocite ore, respectively, using isolated Acidithiobacillus ferrooxidans bacterial strain. Acidothiobacillus ferrooxidans, a chemolithoautotrophic bacterium oxidizes ferrous iron and reduced sulfur compounds, generating sulfuric acid playing a crucial role in the solubilization of iron from laterite ore and copper from chalcocite. In the case of laterite ore, the bacterium’s iron oxidation activity helps release iron from the mineral matrix, making it more accessible for extraction. Similarly, with chalcocite, A. ferrooxidans facilitates the dissolution of copper from chalcocite (Cu2S) through its sulfur-oxidizing capabilities. The synthesized bimetallic nanoparticles were characterized using various techniques, including SEM, XRD, EDS, FTIR, and BET analysis. Fenton’s oxidation and Sono-Fenton’s oxidation of mixture ametryn and dicamba in a solution catalyzed by the bioleached Fe-Cu bimetallic nanoparticles were found to be effective, with ametryn degradation reaching 96.4% and 94.2%, and dicamba degradation reaching 98.1% and 99.3%, respectively, at a catalyst loading of 0.5 g/L. The removal efficiency increased with increasing catalyst loading up to 0.5 g/L and increasing H2O2 dosage up to 500 mg/L. Sono-Fenton’s oxidation led to higher COD reduction of 78.41% compared to conventional Fenton oxidation 70.42% with a reaction rate of 0.039/Min and 0.0053/Min respectively. The study demonstrates the potential of bioleached iron-copper bimetallic nanoparticles as a sustainable replacement for commercial catalysts in the oxidative degradation of herbicides. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.