Search results for "Batch reactor"
showing 10 items of 50 documents
Effect of pH and nitrite concentration on nitrite oxidation rate
2011
The effect of pH and nitrite concentration on the activity of the nitrite oxidizing bacteria (NOB) in an activated sludge reactor has been determined by means of laboratory batch experiments based on respirometric techniques. The bacterial activity was measured at different pH and at different total nitrite concentrations (TNO 2). The experimental results showed that the nitrite oxidation rate (NOR) depends on the TNO 2 concentration independently of the free nitrous acid (FNA) concentration, so FNA cannot be considered as the real substrate for NOB. NOB were strongly affected by low pH values (no activity was detected at pH 6.5) but no inhibition was observed at high pH values (activity wa…
Detection and prevention of enhanced biological phosphorus removal deterioration caused by Zoogloea overabundance.
2008
A sequencing batch reactor was operated in the conventional anaerobic-aerobic mode for enhanced biological phosphorus removal using acetate as the sole substrate. Despite the nutrients concentrations in the influent being high enough to satisfy the biological requirements, Zoogloea ramigera managed to grow in the system until it had negative effects on the process performance. The excess of exocellular polymeric material produced by this microorganism contributed to a viscous bulking phenomenon and caused important settling problems. The examination of the sludge under the microscope was a valuable tool to diagnose the cause of the imbalance in the process. The strategy adopted to avoid the…
Extruded Expanded Polystyrene Sheets Coated by TiO2 as New Photocatalitic Materials for Foodstuffs Packaging
2012
Nanostructured, photoactive anatase TiO2 sol prepared under very mild conditions using titanium tetraisopropoxide as the precursor is used to functionalise extruded expanded polystyrene (XPS) sheets by spray-coating resulting in stable and active materials functionalised by TiO2 nanoparticles. Photocatalytic tests of these sheets performed in a batch reactor in gas-solid system under UV irradiation show their successful activity in degrading probe molecules (2-propanol, trimethylamine and ethene). Raman spectra ensure the deposition of TiO2 as crystalline anatase phase on the polymer surface. The presence of TiO2 with respect to polymer surface can be observed in SEM images coupled to EDAX …
Utilization of enzymatic detergents to clean inorganic membranes fouled by whey proteins
2005
In this work inorganic membranes used for whey protein fractionation were cleaned with enzymatic detergents. The inorganic membrane Carbosep ® M1 (Orelis S.A., France), of 150 kg/mol molecular weight cut-off and ZrO2 filtering layer, was used and the commercial detergent P3-Ultrasil ® 62 (Henkel IbS.A., Spain) was selected for the cleaning. Hydraulic and chemical methods were considered to characterize the membrane cleanliness. Cleaning efficiency was observed to be a function of the operating conditions: recycling versus non-recycling of permeate, cleaning solution pH, enzymatic agent concentration and cleaning time. The optimum conditions to perform the cleaning were related to the optimu…
Basic kinetic model for the reaction yielding linear polyurethanes. II
1995
On the basis of the gradual polyaddition kinetic model developed earlier, an attempt was made to provide a generalized mathematical model for the set of reactions yielding linear polyurethanes. The model is a system of first-order ordinary differential equations. It was assumed at the present stage of this model that the rate constants for the reaction considered do not change. The model developed was then solved numerically. Average molecular weight of the polymer and composition data for oligomers were calculated for a constant volume batch reactor and varied process parameters. The GPC method, which was tested for model urethane oligomers, was employed to verify the model developed. The …
Surfactant Assisted Polymerization of Tetrafluoroethylene in Supercritical Carbon Dioxide with a Pilot Scale Batch Reactor.
2008
Chain-free radical polymerization of tetrafluoroethylene (TFE) was carried out in supercritical carbon dioxide (scCO2), at 50 °C and 121–133 bar, with tertiary-amyl-per-pivalate as a free radical initiator, using a 5-L pilot scale batch reactor. Experiments were carried out both in the absence and in the presence of perfluoropolyether (PFPE) carboxylate surfactants. Stabilizers were employed under the free acid form and as sodium and calcium salts. An expanded fibrillated poly(TFE) was obtained in all experiments. In the case of surfactant-free polymerizations, the product was mainly constituted by irregular shape macroparticles having size in the range 200–500 μm. Quite interestingly, when…
Erratum to “New time-dependent Monte Carlo algorithm designed to model three-phase batch reactor processes: applications on 2,4-dinitro-toluene hydro…
2003
Erratum to “New time-dependent Monte Carlo algorithm designed to model three-phase batch reactor processes: applications on 2,4-dinitro-toluene hydrogenation on Pd/C catalysts” [Chem. Eng. J. 91 (2003) 133–142] Giampaolo Barone a,b, Dario Duca a,b,∗ a Dipartimento di Chimica Inorganica ed Analitica, Universita di Palermo, Viale delle Scienze, I-90128 Palermo, Italy b Dipartimento di Scienze Farmaceutiche, Universita di Salerno, Via Ponte don Melillo, I-84084 Fisciano, Salerno, Italy
Removal of bis (2-ethylhexyl) phthalate from reject water in a nitrogen-removing sequencing batch reactor.
2003
Reject water from sewage sludge processing may contain high concentrations of nutrients and organic pollutants and cause internal pollution load at a sewage treatment plant (STP) if circulated to the headworks of an STP. In the present study removal of nitrogen and bis (2-ethylhexyl) phthalate (DEHP) from reject water was studied in two sequencing batch reactors (SBRs) with different aerobic/anoxic periods during a 6-h total cycle period. Ammonia-nitrogen (NH(4)-N) was almost totally removed in both reactors, apparently by nitrification throughout the run, while denitrification declined with decreasing SCOD in the influent resulting in an increase in the effluent nitrate-nitrogen (NO(3)-N) …
Effect of long-term salinity increase on nitritation and denitritation kinetics in activated sludge and granular sludge reactors
2017
The aim of this work was to investigate the effects of moderate and drastic long-termincrease of salinity.Particularly, the study was aimed at assessing the shock effecton nitritationand denitritation kineticsof halophilic biomass inboth forms:flocculent activated sludge and granular sludge.
Heterogeneous photocatalytic degradation of pharmaceuticals in water by using polycrystalline TiO2 and a nanofiltration membrane reactor
2006
Abstract A study of the photodegradation of different pharmaceuticals [furosemide, ranitidine (hydrochloride), ofloxacine, phenazone, naproxen, carbamazepine and clofibric acid] in aqueous medium at various pHs by using a batch photoreactor and a photocatalytic membrane reactor working in recirculation regime was carried out. Polycrystalline TiO 2 was used as the photocatalyst, and different membranes (NTR 7410, PAN GKSS HV3/T, N 30 F, NF PES 10) were tested. A different adsorption of the substrates onto the catalyst surface was observed owing to the hydrophilic/hydrophobic character of the catalyst, depending on the pH. The photodegradation of the seven molecules in the batch reactor was s…