scholarly journals Modelling mesophilic-thermophilic temperature transitions experienced by an aerobic membrane bioreactor treating furfural plant effluent

Water SA ◽  
2019 ◽  
Vol 45 (3 July) ◽  
Author(s):  
LG Kay ◽  
CJ Brouckaert ◽  
RC Sindall
Keyword(s):  
Membrane Bioreactor ◽  
Sugar Mill ◽  
Unsteady State ◽  
Model Simulations ◽  
Microbial Kinetics ◽  
Thermophilic Conditions ◽  
Different Temperatures ◽  
Plant Data ◽  
By Products ◽  
Treating Effluent

A mathematical model was developed of an aerobic membrane bioreactor (MBR) treating effluent from a by-products facility at a sugar mill producing furfural, based on measurements of microbial kinetics and stoichiometry at different temperatures. The model was calibrated and validated against plant data using volumetric flow into the MBR and volumetric sludge wasting from the MBR as inputs.  The model is able to predict steady-state and unsteady-state operation of the MBR under both mesophilic and thermophilic conditions, and the transitions between the two regimes.  Comparison of model simulations and plant data suggests that thermophilic operation is advantageous, but it is less stable than mesophilic operation and frequent feed disruptions can have detrimental effects on MBR operation.

Methanogenesis in sediments from deep lakes at different temperatures (2–70°C)

1997 ◽  
Vol 36 (6-7) ◽  
pp. 57-64 ◽  
Author(s):  
Alla N. Nozhevnikova ◽  
C. Holliger ◽  
A. Ammann ◽  
A. J. B. Zehnder
Keyword(s):  
Organic Matter ◽  
Microbial Communities ◽  
Methane Production ◽  
Low Temperatures ◽  
Main Question ◽  
Deep Lakes ◽  
Temperature Range ◽  
Wide Range ◽  
Thermophilic Conditions ◽  
Different Temperatures

Methanogenic degradation of organic matter occurs in a wide temperature range from psychrophilic to extreme thermophilic conditions. Mesophilic and thermophilic methanogenesis is relatively well investigated, but little is known about low temperature methanogenesis and psychrophilic methanogenic communities. The aim of the present work was to study methanogenesis in a wide range of temperatures with samples from sediments of deep lakes. These sediments may be considered deposits of different types of microorganisms, which are constantly exposed to low temperatures. The main question was how psychrophilic methanogenic microbial communities compare to mesophilic and thermophilic ones. Methanogenesis in a temperature range of 2–70°C was investigated using sediment samples from Baldegger lake (65 m) and Soppen lake (25 m), Switzerland. Methane production from organic matter of sediments occurred at all temperatures tested. An exponential dependence of methane production rate was found between 2 and 30°C. Methanogenesis occurred even at 70°C. At the same time stable methane production from organic matter of sediments was observed at temperatures below 10°C. Methanogenic microbial communities were enriched at different temperatures. The communities enriched at 4–8°C had the highest activity at low temperatures indicating that a specific psychrophilic community exists. Addition of substrates such as cellulose, volatile fatty acids (butyrate, propionate, acetate), methanol and H2/CO2 stimulated methane production at all temperatures. H2/CO2 as well as methanol were directly converted to methane under thermophilic conditions. At low temperatures these substrates were converted to methane by a two-step process. First acetate was formed, followed by methane production from acetate. When acetate concentrations were high, acetoclastic methanogenesis was inhibited at low temperatures. This reaction appears to be one of the “bottle neck” in psychrophilic methanogenesis.

scholarly journals Influence of the temperature and ultrasound application in drying kinetics of apple skin

2018 ◽  
Author(s):  
Juan A. Cárcel ◽  
Matheus P. Martins ◽  
Edgar J. Cortés ◽  
Carmen Rosselló ◽  
Ramón Peña
Keyword(s):  
Physical Structure ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Drying Time ◽  
Different Temperatures ◽  
Ultrasound Application ◽  
Quality Of Products ◽  
Drying Conditions ◽  
Kinetics Of ◽  
By Products

The great amount of waste produced by food industry contains interesting bioactive compounds. The extraction of these compounds requires the by-products previous stabilization being the convective drying one of most used techniques to this end. Drying conditions can affect both drying kinetics and final quality of products. The apple skin, byproduct of apple juice or cider industries, is rich in functional compounds such as polyphenols or vitamin C. The main goal of this contribution was to quantify the influence of temperature and ultrasound application in drying kinetics of apple skin. For this purpose, drying experiments at different temperatures (-10, 30, 50 and 70 ºC) and with (20.5 kW/m3) and without application of ultrasound were carried out. Drying kinetics were modelled by using a diffusion based model. As can be expected, the higher the temperature the faster the drying. Ultrasound application accelerated the process at every temperature tested being the influence slightly lower than found from the literature for other products. This can be attributed at the physical structure of the apple skin, less porous than the pulp. In any case, the application of ultrasound significantly reduced the drying time. Keywords: by-products; dehydration;diffusivity; mass transfer

Kinetic and thermodynamic study of Os(VIII) catalysed oxidation of glycine by ferrate(VI) in alkaline medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Main Product ◽  
Activation Parameters ◽  
Basic Medium ◽  
First Order ◽  
Catalysed Oxidation ◽  
Rate Of Reaction ◽  
Different Temperatures ◽  
Experimental Findings ◽  
Kinetic And Thermodynamic Study ◽  
By Products

Kinetic and thermodynamic investigation on Os(VIII) catalysed oxidation of glycine by ferrate(VI) has been done in basic medium and in the temperature range 30– 450C. Rate of oxidation increases with increase in [FeO4]2- and [Os(VI)] and shows first order dependence. Rate of oxidation also increases with the increase in [S] but order is fractional. The rate decreases with an increase in pH. Rate of reaction is independent of [KCl], [KNO3] and change in ionic strength. The values of rate constant observed at four different temperatures were used to calculate the activation parameters. The energy of activation (ΔE*) of the reaction at pH 11 and temperature 350C was found to be 49.56 kJmol-1. [OsO4(H2O)2] and [FeO42−] are proposed to be the reactive species of Os(VIII) and Fe(VI) respectively in the present investigation. Formaldehyde is found to be main product of the reaction along with carbon dioxide and ammonia as by products. On the basis of experimental findings, a suitable mechanism consistent with the observed kinetics is proposed and a rate law has been derived on the basis of obtained data.

Pharmaceutical rejection by membranes for wastewater reclamation and reuse

2004 ◽  
Vol 50 (2) ◽  
pp. 239-244 ◽  
Author(s):  
G.-Y. Park ◽  
J.H. Lee ◽  
I.S. Kim ◽  
J. Cho
Keyword(s):  
Molecular Weight ◽  
Membrane Bioreactor ◽  
Free Water ◽  
Water Source ◽  
Hydrodynamic Condition ◽  
Drinking Water Source ◽  
Wastewater Reclamation ◽  
Mass Transfer Parameter ◽  
Wastewater Reclamation And Reuse ◽  
By Products

Various membranes, which have different materials and nominal molecular weight cut-offs (MWCO), were compared in terms of rejection of ibuprofen and removal of effluent organic matter (EfOM) from membrane bioreactor (MBR), because pharmaceutical compounds contain a potential risk and EfOM is the precursor of carcinogenic disinfection by-products when reusing for drinking water source. To provide equivalent comparison with respect to hydrodynamic condition, mass transfer parameter, J0/k ratio, was used. A tight-UF membrane with a molecular weight cut off of 8,000 daltons exhibited 25∼95% removal efficiencies of ibuprofen with a molecular weight of 206 with and without presence of EfOMMBR. EfOMMBR caused the reduction of ibuprofen removal efficiency for UF membrane. Rejection of EfOMMBR by UF and NF membranes ranged 29∼47% and 69∼86%, respectively. UF membrane could successfully remove ibuprofen at lower J0/k ratio range (≤1) in organic free water but could not efficiently reject ibuprofen with a relatively hydrophilic EfOMMBR (SUVA ≤3).

Treatment of a landfill leachate containing compounds of pharmaceutical origin

2008 ◽  
Vol 58 (3) ◽  
pp. 597-602 ◽  
Author(s):  
M. Matošić ◽  
S. Terzić ◽  
H. Korajlija Jakopović ◽  
I. Mijatović ◽  
M. Ahel
Keyword(s):  
Vitamin C ◽  
Landfill Leachate ◽  
Membrane Bioreactor ◽  
Leachate Treatment ◽  
By Products

Paper reports the results of landfill leachate treatment with membrane bioreactor, nanofiltration and ozonation. Investigated leachate encompasses a number of specific compounds of pharmaceutical origin, including a suite of by-products deriving from the production of vitamin C and propyphenazone. Low biodegradability was observed in MBR (16%) for propyphenazone, while the removal of intermediates from the vitamin C-synthesis was moderate, reaching 30% for diacetone sorbose (DAS) and 69% for diacetone alpha-keto-gulonic acid (DAG). Ozonation almost completely removed propyphenazone but failed to significantly oxidise intermediates from the vitamin C-synthesis. Nanofiltration of the leachate succeeded to remove 99% of DAG and 79% of propyphenazone which made it the most efficient among techniques used.

scholarly journals Degradation of hop latent viroid during anaerobic digestion of infected hop harvest residues

2021 ◽  
Author(s):  
Michael Helmut Hagemann ◽  
Ute Born ◽  
Elke Sprich ◽  
Luitgardis Seigner ◽  
Hans Oechsner ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Real Time Pcr ◽  
Agricultural Practices ◽  
Pathogenic Fungi ◽  
Pcr Analysis ◽  
Harvest Residues ◽  
Severe Stunting ◽  
Thermophilic Fermentation ◽  
Thermophilic Conditions ◽  
Different Temperatures

AbstractThe citrus bark cracking viroid (CBCVd) was identified as causal agent for a severe stunting disease in hops. Viroids are highly stable parasitic RNAs, which can be easily transmitted by agricultural practices. Since CBCVd has recently been detected in two European countries a growing concern is that this pathogen will further spread and thereby threaten the European hop production. Biogas fermentation is used to sanitize hop harvest residues infected with pathogenic fungi. Consequently, the aim of this study was to test if biogas fermentation can contribute to viroid degradation at mesophilic (40 °C) and thermophilic (50 °C) conditions. Therefore, a duplex reverse transcription real-time PCR analysis was developed for CBCVd and HLVd detection in biogas fermentation residues. The non-pathogenic hop latent viroid (HLVd) was used as viroid model for the pathogenic CBCVd. The fermentation trials showed that HLVd was significantly degraded after 30 days at mesophilic or after 5 days at thermophilic conditions, respectively. However, sequencing revealed that HLVd was not fully degraded even after 90 days. The incubation of hop harvest residues at different temperatures between 20 and 70 °C showed that 70 °C led to a significant HLVd degradation after 1 day. In conclusion, we suggest combining 70 °C pretreatment and thermophilic fermentation for efficient viroid decontamination.

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