Faculty Publications

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Author: search.filters.author.Thalla, A.K.Subject: search.filters.subject.bioreactor

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    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 Ltd
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    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.
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    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.