Search results for "TRIF"
showing 10 items of 1419 documents
Nitrous oxide from moving bed based integrated fixed film activated sludge membrane bioreactors
2017
Abstract The present paper reports the results of a nitrous oxide (N 2 O) production investigation in a moving bed based integrated fixed film activated sludge (IFAS) membrane bioreactor (MBR) pilot plant designed in accordance with the University of Cape Town layout for biological phosphorous removal. Gaseous and liquid samples were collected in order to measure the gaseous as well as the dissolved concentration of N 2 O. Furthermore, the gas flow rate from each reactor was measured and the gas flux was estimated. The results confirmed that the anoxic reactor represents the main source of nitrous oxide production. A significant production of N 2 O was, however, also found in the anaerobic …
Moving bed membrane bioreactors for carbon and nutrient removal: The effect of C/N variation
2017
In this paper, an experimental campaign was carried out on a University of Cape Town Integrated Fixed Film Activated Sludge Membrane Bioreactor (UCT-IFAS-MBR) pilot plant. The aim of the study was to evaluate the effect of the influent C/N ratio on the system performance in terms of organic carbon, nitrogen and phosphorus removal, biomass viability (through respirometry), activated sludge features and membrane filtration properties. The experiments were organized into three phases, characterized by a variation of the C/N ratio (namely, Phase I: C/N= 5, Phase II: C/N =10; Phase III: C/N = 2). The results highlighted that the system performance was significantly affected by C/N ratio. The rem…
Uncertainty and sensitivity analysis for reducing greenhouse gas emissions from wastewater treatment plants.
2020
Abstract This paper presents the sensitivity and uncertainty analysis of a plant-wide mathematical model for wastewater treatment plants (WWTPs). The mathematical model assesses direct and indirect (due to the energy consumption) greenhouse gases (GHG) emissions from a WWTP employing a whole-plant approach. The model includes: i) the kinetic/mass-balance based model regarding nitrogen; ii) two-step nitrification process; iii) N2O formation both during nitrification and denitrification (as dissolved and off-gas concentration). Important model factors have been selected by using the Extended-Fourier Amplitude Sensitivity Testing (FAST) global sensitivity analysis method. A scenario analysis h…
Pilot scale experiment with MBR operated in intermittent aeration condition: analysis of biological performance.
2014
The effect of intermittent aeration (IA) on a MBR system was investigated. The study was aimed at ana- lyzing different working conditions and the influence of different IA cycles on the biological performance of the MBR pilot plant, in terms of organic carbon and ammonium removal as well as extracellular poly- meric substances (EPSs) production. The membrane modules were placed in a separate compartment, continuously aerated. This configuration allowed to disconnect from the filtration stage the biological phenomena occurring into the IA bioreactor. The observed results highlighted good efficiencies, in terms of organic carbon and ammonium removal. It was noticed a significant soluble micr…
Composting of bio-waste, aerobic and anaerobic sludges – Effect of feedstock on the process and quality of compost
2011
In-vessel composting of three stocks with originally different degree of organic matter degradation was conducted for: (1) kitchen source-separated bio-waste (BW), (2) aerobic (AS) as well as (3) anaerobic sludges (AnS) from municipal wastewater treatment plant. Composting experiment lasted over a year. The highest activity of the process was in the BW compost. It was implied by the highest temperature, CO(2) release, ammonification and nitrification, intensive accumulation and removal of low-weight carboxylic acids (water- and NaOH-extractable). Between the sludges higher mineralization and CO2 release was in AnS, while ammonification and nitrification were higher in AS compost; no signifi…
Calibration of denitrifying activity of polyphosphate accumulating organisms in an extended ASM2d model
2010
Abstract This paper presents the results of an experimental study for the modelling and calibration of denitrifying activity of polyphosphate accumulating organisms (PAOs) in full-scale WWTPs that incorporate simultaneous nitrogen and phosphorus removal. The convenience of using different yields under aerobic and anoxic conditions for modelling biological phosphorus removal processes with the ASM2d has been demonstrated. Thus, parameter ηPAO in the model is given a physical meaning and represents the fraction of PAOs that are able to follow the DPAO metabolism. Using stoichiometric relationships, which are based on assumed biochemical pathways, the anoxic yields considered in the extended A…
Simultaneous nitrogen and organic carbon removal in aerobic granular sludge reactors operated with high dissolved oxygen concentration
2013
Simultaneous nitrification and denitrification (SND) together with organic removal in granules is usually carried out without Dissolved Oxygen (DO) concentration control, at ‘‘low DO’’ (with a DO 7–8 mg/L, during feast and famine conditions respectively). In particular, different strategies of cultivation and several organic and nitrogen loading rate have been applied, in order to eval- uate the efficiencies in SND process without dissolved oxygen control. The results show that, even under conditions of high DO concentration, nitrogen and organic matter can be simultaneously removed, with efficiency >90%. Nevertheless, the biological conditions in the inner layer of the granule may change sig- …
Hybrid activated sludge/biofilm process for the treatment of municipal wastewater in a cold climate region: a case study.
2011
A hybrid activated sludge/biofilm process was investigated for wastewater treatment in a cold climate region. This process, which contains both suspended biomass and biofilm, usually referred as IFAS process, is created by introducing plastic elements as biofilm carrier media into a conventional activated sludge reactor. In the present study, a hybrid process, composed of an activated sludge and a moving bed biofilm reactor was used. The aim of this paper has been to investigate the performances of a hybrid process, and in particular to gain insight the nitrification process, when operated at relatively low MLSS SRT and low temperatures. The results of a pilot-scale study carried out at the…
Xenobiotic metabolizing enzyme activities and viability are well preserved in EDTA-isolated rat liver parenchymal cells after cryopreservation
1995
Rat liver parenchymal cells (PC) were isolated by EDTA perfusion and were purified by a subsequent Percoll centrifugation. The isolated PC had a viability of 95%, as judged by trypan blue exclusion. Freshly isolated PC were cryopreserved with an optimized protocol in a computer-controlled freezer. After thawing, the PC still retained a viability of 89%. The activities of representative xenobiotic metabolizing enzymes were compared between freshly isolated and cryopreserved PC after thawing. The cytochrome P450 content and the cytochrome P450 2C11 isoenzyme activity, determined by hydroxylation of testosterone in intact cells, were not affected by the cryopreservation. The following phase II…
On the activity of trifluoperazine and palmitoylcarnitine in mice: Delayed hypersensitivity models
2001
Abstract The effect of pre- and post-challenge treatments with trifluoperazine and palmitoylcarnitine, two protein kinase C (PKC) inhibitors characterised by their interaction with the phospholipid enzyme cofactor, on the inflammation caused by delayed hypersensitivity (DTH) to dinitrofluorobenzene (DNFB) and sheep red blood cells (SRBC) in mice is reported. The activity of dexamethasone and two immunosupressors, azathioprine and methotrexate, is also evaluated. The effectiveness of pre-treatment with each of the test drugs diminished when the DNFB challenge dose increased, whereas trifluoperazine and azathioprine were more active when administered after the challenge at the high DNFB dose.…