Volatile fatty acid formation in an anaerobic hybrid reactor

Büyükkamacı, Nurdan; Filibeli, Ayşe

doi:10.1016/s0032-9592(03)00295-4

Cited by 98 publications

(44 citation statements)

References 9 publications

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“…Buyukkamaci and Filibeli (2004) reported a higher methanogenic activity in the upper part and a higher acetogenic activity in the bottom of a hybrid (UASB and anaerobic filter) reactor. In contrast with these findings, the activity was not segregated over the sludge bed of R2 on day 42 (Table II).…”

Section: Activity Segregation Along the Sludge Bedmentioning

confidence: 98%

Acidification of methanol‐fed anaerobic granular sludge bioreactors by cobalt deprivation: Induction and microbial community dynamics

Fermoso¹,

Collins²,

Bartacek³

et al. 2007

Biotech & Bioengineering

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The acidification of mesophilic (30 degrees C) methanol-fed upflow anaerobic sludge bed (UASB) reactors induced by cobalt deprivation from the influent was investigated by coupling the reactor performance (pH 7.0; organic loading rate 4.5 g COD . L(-1) . d(-1)) to the microbial ecology of the bioreactor sludge. The latter was investigated by specific methanogenic activity (SMA) measurements and fluorescence in situ hybridization (FISH) to quantify the abundance of key organisms over time. This study hypothesized that under cobalt limiting conditions, the SMA on methanol of the sludge gradually decreases, which ultimately results in methanol accumulation in the reactor effluent. Once the methanol accumulation surpasses a threshold value (about 8.5 mM for the sludge investigated), reactor acidification occurs because acetogens outcompete methylothrophic methanogens at these elevated methanol concentrations. Methanogens present in granular sludge at the time of the acidification do not use methanol as the direct substrate and are unable to degrade acetate. Methylotrophic/acetoclastic methanogenic activity was found to be lost within 10 days of reactor operation, coinciding with the disappearance of the Methanosarcina population. The loss of SMA on methanol can thus be used as an accurate parameter to predict reactor acidification of methanol-fed UASB reactors operating under cobalt limiting conditions.

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Section: Activity Segregation Along the Sludge Bedmentioning

confidence: 98%

Acidification of methanol‐fed anaerobic granular sludge bioreactors by cobalt deprivation: Induction and microbial community dynamics

Fermoso¹,

Collins²,

Bartacek³

et al. 2007

Biotech & Bioengineering

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“…Following acetogenesis, methanogens convert acetic acid to CO 2 and CH 4 . Volatile fatty acids are one of the important indicators for measuring anaerobic digestion performance because they are closely related to the changes in pH, alkalinity, and the activity of methanogens [17,25]. Fig.…”

Section: Ph Alkalinity and Ammonium Nitrogen Variations In The Leacmentioning

confidence: 99%

Evaluation of Biogas Production Potential by Dry Anaerobic Digestion of Switchgrass–Animal Manure Mixtures

Ahn

Smith

Kondrad

et al. 2009

Appl Biochem Biotechnol

167

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Anaerobic digestion is a biological method used to convert organic wastes into a stable product for land application with reduced environmental impacts. The biogas produced can be used as an alternative renewable energy source. Dry anaerobic digestion [>15% total solid (TS)] has an advantage over wet digestion (<10% TS) because it allows for the use of a smaller volume of reactor and because it reduces wastewater production. In addition, it produces a fertilizer that is easier to transport. Performance of anaerobic digestion of animal manure-switchgrass mixture was evaluated under dry (15% TS) and thermophilic conditions (55 degrees C). Three different mixtures of animal manure (swine, poultry, and dairy) and switchgrass were digested using batch-operated 1-L reactors. The swine manure test units showed 52.9% volatile solids (VS) removal during the 62-day trial, while dairy and poultry manure test units showed 9.3% and 20.2%, respectively. Over the 62 day digestion, the swine manure test units yielded the highest amount of methane 0.337 L CH4/g VS, while the dairy and poultry manure test units showed very poor methane yield 0.028 L CH4/g VS and 0.002 L CH4/g VS, respectively. Although dairy and poultry manure performed poorly, they may still have high potential as biomass for dry anaerobic digestion if appropriate designs are developed to prevent significant volatile fatty acid (VFA) accumulation and pH drop.

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“…The HPr/HAc ratio was calculated to be 0.06 -0.25 and 1.13 -1.25 for mesophilic and thermophilic treatments, respectively. As known, if this ratio reaches 1.4, the system would fail (Buyukkamaci & Filibeli, 2004).…”

Section: Intermediate Products Ph and Alkalinitymentioning

confidence: 98%

Comparison of thermophilic and mesophilic anaerobic treatment for potato processing wastewater using a contact reactor

2017

Global NEST Journal

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In this study, different organic loading rates (OLRs) ranging from 1.1 to 5.0 kg COD/m 3 ·day were used to assess the performance of an anaerobic reactor at the optimum mesophilic (35°C) and thermophilic (55°C) temperatures. The methane gas production rate of the thermophilic treatment was higher than that of the mesophilic treatment. The efficiency of chemical oxygen demand (COD) removal was observed to range from 89.12 to 93.20% following the thermophilic anaerobic treatment and from 76.36 to 92.62% following the mesophilic treatment. The average VFA (volatile fatty acid)/alkalinity ratio of the effluent was 0.3 under both thermophilic and mesophilic conditions for all the OLR applications. The HPr/HAc (propionic acid/acetic acid) ratio was calculated as 0.16 and 1.3 for the mesophilic and thermophilic treatments, respectively. For the mesophilic treatment, the average methane gas production was found to be 0.394 m 3 CH4/kg CODremoved while it was 0.42 m 3 CH4/kg CODremoved for the thermophilic experiment. However, the sludge settleability of the mesophilic treatment was better than that of the thermophilic treatment.

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Volatile fatty acid formation in an anaerobic hybrid reactor

Cited by 98 publications

References 9 publications

Acidification of methanol‐fed anaerobic granular sludge bioreactors by cobalt deprivation: Induction and microbial community dynamics

Acidification of methanol‐fed anaerobic granular sludge bioreactors by cobalt deprivation: Induction and microbial community dynamics

Evaluation of Biogas Production Potential by Dry Anaerobic Digestion of Switchgrass–Animal Manure Mixtures

Comparison of thermophilic and mesophilic anaerobic treatment for potato processing wastewater using a contact reactor

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