A Kinetic Study on the Methanogenesis Process in Anaerobic Digestion

1989 ◽  
Vol 21 (4-5) ◽  
pp. 175-186 ◽  
Author(s):  
C. Y. Lin ◽  
T. Noike ◽  
H. Furumai ◽  
J. Matsumoto
Keyword(s):  
Anaerobic Digestion ◽  
Substrate Concentration ◽  
Volatile Fatty Acid ◽  
Kinetic Mechanism ◽  
High Concentration ◽  
Two Phase ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
The Relationship ◽  
Rate Limiting

Results obtained from experiments on two-phase anaerobic digestion using a high concentration of a volatile fatty acid (VFA) mixture were used to elucidate the kinetic mechanism of the methanogenesis process. The mixture consisted of the major intermediate products of anaerobic digestion, i.e., acetic acid (HAc), propionic acid (HPr) and butyric acid (HBu). The relationship between the rate of substrate utilization and substrate concentration in the digesters was in the form of a Michaelis-Menten equation. The rate-limiting step of the methanogenesis process, i.e., the conversion of HAc to methane, was speeded up in the digesters and this was proved kinetically. A method for determining kinetic constants for substrate-specific microorganisms was suggested. A simulation model for predicting the effluent substrate concentration was demonstrated. The effluent substrate concentration of an anaerobic digester fed by a multisubstrate was found to be simulatively predictable from its influent component substrates.

Characteristics of carbohydrate degradation and the rate-limiting step in anaerobic digestion

1985 ◽  
Vol 27 (10) ◽  
pp. 1482-1489 ◽  
Author(s):  
Tatsuya Noike ◽  
Ginro Endo ◽  
Juu-En Chang ◽  
Jun-Ichi Yaguchi ◽  
Jun-Ichiro Matsumoto
Keyword(s):  
Anaerobic Digestion ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Carbohydrate Degradation ◽  
Rate Limiting

Enhancement of the conventional anaerobic digestion of sludge: comparison of four different strategies

2011 ◽  
Vol 64 (2) ◽  
pp. 375-383 ◽  
Author(s):  
S. I. Pérez-Elvira ◽  
M. Fdz-Polanco ◽  
F. Fdz-Polanco
Keyword(s):  
Anaerobic Digestion ◽  
Thermal Hydrolysis ◽  
General Increase ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Key Factor ◽  
Thermophilic Digestion ◽  
Pre Treatment ◽  
Treatment Alternatives ◽  
Rate Limiting

Anaerobic digestion (AD) is the preferred option to stabilize sludge. However, the rate limiting step of solids hydrolysis makes it worth modifing the conventional mesophilic AD in order to increase the performance of the digester. The main strategies are to introduce a hydrolysis pre-treatment, or to modify the digestion temperature. Among the different pre-treatment alternatives, the thermal hydrolysis (TH) at 170 °C for 30 min, and the ultrasounds pre-treatment (US) at 30 kJ/kg TS were selected for the research, while for the non-conventional anaerobic digestion, the thermophilic (TAD) and the two-stage temperature phased AD (TPAD) were considered. Four pilot plants were operated, with the same configuration and size of anaerobic digester (200 L, continuously fed). The biogas results show a general increase compared to the conventional digestion, being the highest production per unit of digester for the process combining the thermal pre-treatment and AD (1.4 Lbiogas/Ldigester·day compared to the value of 0.26 obtained in conventional digesters). The dewaterability of the digestate became enhanced for processes TH + AD and TPAD when compared with the conventional digestate, while it became worse for processes US + AD and TAD. In all the research lines, the viscosity in the digester was smaller compared to the conventional (which is a key factor for process performance and economics), and both thermal pre-treatment and thermophilic digestion (TAD and TPAD) assure a pathogen free digestate.

scholarly journals Kinetic Mechanism of Human DNA Ligase I Reveals Magnesium-dependent Changes in the Rate-limiting Step That Compromise Ligation Efficiency

2011 ◽  
Vol 286 (26) ◽  
pp. 23054-23062 ◽  
Author(s):  
Mark R. Taylor ◽  
John A. Conrad ◽  
Daniel Wahl ◽  
Patrick J. O'Brien
Keyword(s):  
Kinetic Mechanism ◽  
Dna Ligase ◽  
Rate Limiting Step ◽  
Human Dna ◽  
Limiting Step ◽  
Dna Ligase I ◽  
Rate Limiting

scholarly journals Impact of physical structure of granular sludge on methanogenesis and methanogenic community structure

RSC Advances ◽  
2019 ◽  
Vol 9 (51) ◽  
pp. 29570-29578
Author(s):  
Xiaofang Pan ◽  
Lina Wang ◽  
Nan Lv ◽  
Jing Ning ◽  
Mingdian Zhou ◽  
...  
Keyword(s):  
Community Structure ◽  
Anaerobic Digestion ◽  
Granular Sludge ◽  
Physical Structure ◽  
Critical Factors ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

Physical structures of sludge are critical factors determining the performance of the anaerobic digestion process, especially for the rate-limiting step, methanogenesis.

scholarly journals Kinetic Mechanism and the Rate-limiting Step ofPlasmodium vivaxSerine Hydroxymethyltransferase

2015 ◽  
Vol 290 (13) ◽  
pp. 8656-8665 ◽  
Author(s):  
Somchart Maenpuen ◽  
Watcharee Amornwatcharapong ◽  
Pasupat Krasatong ◽  
Jeerus Sucharitakul ◽  
Bruce A. Palfey ◽  
...  
Keyword(s):  
Kinetic Mechanism ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

scholarly journals Preparation and Kinetic Studies of Cross-Linked Chitosan Beads Using Dual Crosslinkers of Tripolyphosphate and Epichlorohydrin for Adsorption of Methyl Orange

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Akhmad Sabarudin ◽  
Armeida D. R. Madjid
Keyword(s):  
Methyl Orange ◽  
Bulk Diffusion ◽  
Kinetic Studies ◽  
Hydroxyl Group ◽  
High Concentration ◽  
Chitosan Beads ◽  
Kinetics Of Adsorption ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

Preparation of cross-linked chitosan beads using dual crosslinkers of tripolyphosphate (TPP) and epichlorohydrin (ECH) for the adsorption and kinetic studies of methyl orange (MO) had been carried out. FTIR spectra showed that TPP could act as the protecting agent of the NH2 group of chitosan and ECH reacted with the primary hydroxyl group of chitosan. Various concentrations of TPP, ECH, and immersing time in the TPP solution for bead formation were studied. The effect of pH and kinetics of adsorption were investigated to define the mechanism of adsorption and rate-limiting step. As a result, pH 3, 10% (w/v) TPP, 5% (v/v) ECH, and 12 h immersing time in TPP were selected as the optimum conditions for preparing the beads as indicated by the highest adsorption amount of MO. The cross-linked chitosan beads’ adsorption capacity for MO under optimum condition was found to be 79.55 mg/g with the adsorption rate constant (k) of 1.29 × 10−3/min. Furthermore, it was found that a low concentration of ECH could maintain the stability of chitosan in acidic conditions, whereas the concentration of TPP and immersing time controlled pore size and morphology of chitosan beads. The mechanism of adsorption of MO was controlled by the pore and rigidity of cross-linked chitosan beads. Bulk diffusion acted as a rate-limiting step, and a high concentration of MO inhibited diffusion and adsorption itself.

Sign in / Sign up

Export Citation Format

Share Document