Photocatalytic Degradation of Two Volatile Fatty Acids in an Annular Plug-Flow Reactor; Kinetic Modeling and Contribution of Mass Transfer Rate

A mathematical model of a plug-flow reactor with a fluid recycle has been elaborated to simulate the VFA production process treating the organic fraction of the municipal solid waste. An alternative hydrolytic reaction model (homogeneous - heterogeneous) is proposed. The effect of a possible methanization step is also considered. The effect of process parameters (solid retention time (SRT), pH, recycle ratio) on the reactor performance is analyzed for parameters based on fruit and vegetable waste. The sensitivity of the model to proposed parameters (suspended biomass and initial biomass concentration) is also evaluated. It is found that the reactor production is very sensitive to the system pH. At low SRT, the production of volatile fatty acids (VFA) is proportional to this parameter. As the SRT increases methanization can reduce the VFA production. The effect of the recycle is negligible for the system and operating conditions studied. The effect of suspended biomass and initial biomass concentration was found to be also negligible. For the system analyzed, the pH is a critical parameter and a plug-flow arrangement (without recycle) seems to be the more reasonable election.

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95/04404 Volatile fatty acids production by mesophilic fermentaiton of mechanically-sorted urban organic wastes in a plug-flow reactor

Fuel and Energy Abstracts ◽

10.1016/0140-6701(95)95962-5 ◽

1995 ◽

Vol 36 (4) ◽

pp. 308

Keyword(s):

Fatty Acids ◽

Volatile Fatty Acids ◽

Flow Reactor ◽

Plug Flow ◽

Organic Wastes ◽

Plug Flow Reactor

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Volatile fatty acids build-up and its effect on E. coli inactivation during excreta stabilisation in single-stage and two-stage systems

Journal of Water Sanitation and Hygiene for Development ◽

10.2166/washdev.2018.160 ◽

2018 ◽

Vol 8 (2) ◽

pp. 257-267 ◽

Cited By ~ 2

Author(s):

Joy Riungu ◽

Mariska Ronteltap ◽

Jules B. van Lier

Keyword(s):

Fatty Acids ◽

Decay Rate ◽

Volatile Fatty Acids ◽

Flow Reactor ◽

Plug Flow ◽

Single Stage ◽

Pathogen Inactivation ◽

Two Stage ◽

E Coli ◽

Reactor Length

Abstract Digestion and co-digestion of faecal matter collected from urine diverting dehydrating toilet faeces (UDDT-F) and mixed organic market waste (OMW) was studied in single stage pilot scale mesophilic plug-flow anaerobic reactors at UDDT-F:OMW ratios 4:1 and 1:0. Escherichia coli inactivation and volatile fatty acids (VFA) build-up was monitored at sampling points located along the reactor profile. When applying UDDT-F:OMW ratio of 4:1 at 12% total solids (TS), E. coli inactivation achieved was 2.3 log times higher than that achieved in UDDT-F:OMW ratio of 1:0. In subsequent trials, a two-stage reactor was researched, applying a UDDT-F:OMW ratio of 4:1 and 10 or 12% TS slurry concentrations. Highest VFA concentrations of 16.3 ± 1.3 g/L were obtained at a pH of 4.9 in the hydrolysis/acidogenesis reactor, applying a UDDT-F:OMW ratio of 4:1 and 12% TS, corresponding to a non-dissociated (ND)-VFA concentration of 6.9 ± 2.0 g/L. The corresponding decay rate reached a value of 1.6 per day. In the subsequent methanogenic plug-flow reactor, a decay rate of 1.1 per day was attained within the first third part of the reactor length, which declined to 0.6 per day within the last third part of the reactor length. Results show that a two-stage system is an efficient way to enhance pathogen inactivation during anaerobic digestion.

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Magnetic actuation of catalytic microparticles for the enhancement of mass transfer rate in a flow reactor

Chemical Engineering Journal ◽

10.1016/j.cej.2016.07.059 ◽

2016 ◽

Vol 306 ◽

pp. 352-361 ◽

Cited By ~ 4

Author(s):

Philip Lisk ◽

Erell Bonnot ◽

Md Taifur Rahman ◽

Robert Pollard ◽

Robert Bowman ◽

...

Keyword(s):

Mass Transfer ◽

Transfer Rate ◽

Flow Reactor ◽

Mass Transfer Rate ◽

Magnetic Actuation

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Effect of Biowaste Sludge Maturation on the Diversity of Thermophilic Bacteria and Archaea in an Anaerobic Reactor

Applied and Environmental Microbiology ◽

10.1128/aem.02260-08 ◽

2009 ◽

Vol 75 (8) ◽

pp. 2566-2572 ◽

Cited By ~ 79

Author(s):

M. Goberna ◽

H. Insam ◽

I. H. Franke-Whittle

Keyword(s):

Fatty Acids ◽

Volatile Fatty Acids ◽

Flow Reactor ◽

Thermophilic Bacteria ◽

Plug Flow ◽

Phylogenetic Groups ◽

Anaerobic Reactor ◽

Prokaryotic Diversity ◽

Major Shift ◽

Stable Community

ABSTRACT Prokaryotic diversity was investigated near the inlet and outlet of a plug-flow reactor. After analyzing 800 clones, 50 bacterial and 3 archaeal phylogenetic groups were defined. Clostridia (>92%) dominated among bacteria and Methanoculleus (>90%) among archaea. Significant changes in pH and volatile fatty acids did not invoke a major shift in the phylogenetic groups. We suggest that the environmental filter imposed by the saline conditions (20 g liter−1) selected a stable community of halotolerant and halophilic prokaryotes.

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Free Convective Mass Transfer at Isosceles Triangular Surfaces of Varying Inclination

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20032080 ◽

2003 ◽

Vol 68 (11) ◽

pp. 2080-2092 ◽

Cited By ~ 1

Author(s):

Martin Keppert ◽

Josef Krýsa ◽

Anthony A. Wragg

Keyword(s):

Mass Transfer ◽

Transfer Rate ◽

Mass Transfer Rate ◽

Mass Transfer Process ◽

Sulfate Solution ◽

Convective Mass Transfer ◽

Varying Length ◽

Inclined Surface ◽

Vertical Case ◽

Limiting Diffusion Current

The limiting diffusion current technique was used for investigation of free convective mass transfer at down-pointing up-facing isosceles triangular surfaces of varying length and inclination. As the mass transfer process, copper deposition from acidified copper(II) sulfate solution was used. It was found that the mass transfer rate increases with inclination from the vertical to the horizontal position and decreases with length of inclined surface. Correlation equations for 7 angles from 0 to 90° were found. The exponent in the ShL-RaL correlation ranged from 0.247 for the vertical case, indicating laminar flow, to 0.32 for inclinations of 60 to 90°, indicating mixed or turbulent flow. The general correlation ShL = 0.358(RaL sin θ)0.30 for the RaL sin θ range from 7 × 106 to 2 × 1011 and inclination range from 15 to 90° was obtained.

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