Volatile fatty acids production from cheese whey: influence of pH, solid retention time and organic loading rate

2018 ◽  
Vol 93 (6) ◽  
pp. 1742-1747 ◽  
Author(s):  
Rolando Rafael Calero ◽  
Borja Lagoa-Costa ◽  
María Mercedes del Coro Fernandez-Feal ◽  
Christian Kennes ◽  
Maria Carmen Veiga
2013 ◽  
Vol 143 ◽  
pp. 525-530 ◽  
Author(s):  
Jianguo Jiang ◽  
Yujing Zhang ◽  
Kaimin Li ◽  
Quan Wang ◽  
Changxiu Gong ◽  
...  

2021 ◽  
Author(s):  
Daniel Battaglia

The five parameters being analyzed are pH, temperature, retention time/organic loading rate, substrate to inoculum ratio, and inhibitors of VFAs. The effect of pH has been shown to produce optimal concentrations of VFAs when outside the optimal range of methanogenesis. Temperature sees different types of VFAs being produced at different concentrations dependant on mesophilic or thermophilic conditions. The organic loading rate (OLR) and retention time (RT) demonstrate similar concepts as longer periods of time allow for more VFAs to be converted from the waste but readily supplying waste to digesters sees higher concentrations produced immediately. The substrate to inoculum ratio (S/I) showed ratios above 1 to be favorable in production as it provided enough inoculum (microorganisms) to convert VFAs effectively. Lastly, the effects of several VFA inhibitors are discussed with regards to their impacts on the anaerobic digestion process and their inhibition of certain VFA’s formation.


1998 ◽  
Vol 33 (4) ◽  
pp. 551-564 ◽  
Author(s):  
Nathalie Imbeault ◽  
Marcel Paquet ◽  
Raynald Côté

Abstract This paper addresses the production of volatile fatty acids with fermentation of whey permeate under acidogenic conditions. The coal-immobilized biomass of an anaerobic fluidized bed reactor operated with a fairly constant hydraulic residence time of 12 min transformed the substrate (whey permeate i.e., essentially lactose) into a blend of acetic, propionic, butyric and isobutyric acids corresponding to between 2 and 19, 1 and 6, 11 and 30, 0 and 2% of the initial load (carbon basis), respectively. There was a slight decrease in the sugar transformation efficiency (65 to 48%) with the increase of the organic loading rate (OLR) which varied from 586 to 3339 g sugar/Lreactord. At the highest OLR of 3339 g sugar/Lreactor.d, the biomass transformed 19% of the substrate into a blend of acetic, propionic, butyric and isobutyric acids. Residual sugar and bio-gas were 52 and 2%, respectively, of the initial load (carbon basis). Cet article fait référence L une étude sur la production d’acides gras volatiles par fermentation anaérobie du perméat de lactosérum dans un bioréacteur. La biomasse fixée aux grains de charbon composant le lit fluidisé, opérant avec un temps de rétention hydraulique de 12 minutes, transformait le substrat (perméat i.e., essentiellement lactose) en un mélange d’acide acétique, propionique, n-butyrique et isobutyrique correspondant respectivement L 2 et 19, 1 et 6, 11 et 30, 0 et 2% de la charge initiale (sur la base d’un bilan de carbone). Il a été possible d’observer une légère diminution de l’efficacité de la biodégradation du sucre (65 L 48%) avec une augmentation du taux de charge organique lequel variait de 586 L 3 339 g de sucre/Lréacteurd. L la charge organique la plus forte, soit 3 339 g de sucre/Lréacteur.d, la biomasse transformait le substrat L 19% en un mélange d’acide acétique, propionique, n-butyrique et isobutyrique. La part du sucre résiduel était de 52% et celle du biogaz L 2% (bilan de carbone).


1989 ◽  
Vol 24 (4) ◽  
pp. 523-536 ◽  
Author(s):  
N. Kosaric ◽  
R. Blaszczyk ◽  
L. Orphan

Abstract Four 20L UASB reactors, R1, R2, R3 and R4 were operated at different upflow velocities of 0.25, 1.0, 1.5, and 0.5 m/h, respectively. Changes in loading rate were achieved by removing part of granules from the bed at a constant volumetric feed rate of 6.2 g COD/(L day). It was found that the granulated bed may adapt to the increased organic loading rate up to about 1.6 kg COD/(kg VSS day) and achieve a 100% conversion of the COD present (composed of volatile fatty acids). Increasing the loading rate over the above value can bring about a decreased COD conversion. At the organic loading rate of 1.6 kg COD/(kg VSS day), the accumulation of granules in reactors R1 and R4 was observed. At the same loading rate, no accumulation of granules was observed in reactor R2 (within 40 days) and in reactor R3 (within 55 days). It was also found that a great number of large granules were washed out from reactors R1 and R4 when the loading rate of about 0.7 kg COD/(kg VSS day) was maintained for about 70 days.


2021 ◽  
Author(s):  
Daniel Battaglia

The five parameters being analyzed are pH, temperature, retention time/organic loading rate, substrate to inoculum ratio, and inhibitors of VFAs. The effect of pH has been shown to produce optimal concentrations of VFAs when outside the optimal range of methanogenesis. Temperature sees different types of VFAs being produced at different concentrations dependant on mesophilic or thermophilic conditions. The organic loading rate (OLR) and retention time (RT) demonstrate similar concepts as longer periods of time allow for more VFAs to be converted from the waste but readily supplying waste to digesters sees higher concentrations produced immediately. The substrate to inoculum ratio (S/I) showed ratios above 1 to be favorable in production as it provided enough inoculum (microorganisms) to convert VFAs effectively. Lastly, the effects of several VFA inhibitors are discussed with regards to their impacts on the anaerobic digestion process and their inhibition of certain VFA’s formation.


2021 ◽  
Vol 38 (1) ◽  
pp. 179-193
Author(s):  
N.C. Ezebuiro ◽  
I. Körner

Volatile fatty acids (VFAs) and trace elements (TEs) interactions (VFAs*TEs) during biomethanization have effects that could be exploited to enhance anaerobic digestion (AD) of biomass. The goal of this study was to validate biocatalytic effects of specialized VFAs*TEs identified from a batch-derived Optimum TEs Configuration (or simply ‘Optimum’) on high organic loading rate (OLR) involving mixed fruit residue (MFR) fed in semi-continuous AD operation. The specialized VFAs*TEs were formulated as Variants of the Optimum and included Optimum –Cobalt (Co) for specialized VFAs*Co effects, and Optimum +Selenium (Se) for specialized VFAs*Se effects. Four duplicate AD reactors were treated with formulations reflecting the Optimum and the Variants. Each duplicate reactor was semi-continuously fed with MFR at varying OLR until instability occurred. Methane production, total volatile organic acidity (FOS) / total alkalinity (TAC) and VFAs fingerprints were measured as main responses. The results showed that reactors of the Optimum and its Variants were unstable at OLR of 8g oDM/L/d, but stability was restored in the Optimum –Co (FOS/TAC values of 0.6 compared to 1.51 and 1.67 for Optimum and Optimum +Se respectively). The average specific CH4 production (Nml/g oDM) of the Optimum and its Variants were Control: 431±36; Optimum: 553±16; Optimum –Co: 580±12; and Optimum +Se: 545±13. Optimum –Co also had the lowest acetic acid and butyric acid accumulation, but had higher propionic acid concentration (0.7 g/L) compared to the Optimum (0.3 g/L) and Optimum +Se (0.4 g/L).


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