Effect of Fe0 addition on volatile fatty acids evolution on anaerobic digestion at high organic loading rates

Biogas production through anaerobic digestion has proven to be one of the most important pillars of the transition into the circular economy concept, a sustainable approach for biorefinery. This work aims to extend and improve knowledge in the anaerobic co-digestion of complementary substrates, given insights into wastes biodegradability and the influence of manure composition on the anaerobic process stability. Anaerobic co-digestion of sugar beet by-products with two kinds of animal manure (pig and cow) was investigated in semi-continuous assays, analyzing both common and non-classical parameters. Co-digestion with manure clearly mitigated the inhibitory effect of volatile fatty acids at high organic loading rates, leading to increases in methane production by 70% and 31% in comparison with individual digestion of sugar beet by-products, for co-digestion with pig and cow manure, respectively. Non-classical parameters could give more insight into the coupling/uncoupling of the anaerobic digestion phases and the involved microorganisms. Indirect parameters indicated that the process failure at the critical organic loading rates was mainly due to methanogenesis inhibition in the co-digestion with pig manure, while in co-digestion with cow manure or in individual digestion of sugar beet by-products, both hydrolysis–acidogenesis and methanogenesis phases were affected. Biomethanation degree refers to the maximum methane potential of organic wastes. Sugar beet by-products required a long digestion-time to reach high biodegradability. However, short digestion-times for co-digestion assays led to a high biomethanation degree.

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Impact of Organic Loading Rate in Volatile Fatty Acids Production and Population Dynamics Using Microalgae Biomass as Substrate

Scientific Reports ◽

10.1038/s41598-019-54914-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 11

Author(s):

Jose Antonio Magdalena ◽

Silvia Greses ◽

Cristina González-Fernández

Keyword(s):

Fatty Acids ◽

Population Dynamics ◽

Organic Matter ◽

Anaerobic Digestion ◽

Volatile Fatty Acids ◽

Building Blocks ◽

Biofuel Production ◽

Organic Loading Rate ◽

Organic Loading ◽

Wide Range

AbstractVolatile fatty acids (VFAs) are regarded as building blocks with a wide range of applications, including biofuel production. The traditional anaerobic digestion used for biogas production can be alternatively employed for VFAs production. The present study aimed at maximizing VFAs productions from Chlorella vulgaris through anaerobic digestion by assessing the effect of stepwise organic loading rates (OLR) increases (3, 6, 9, 12 and 15 g COD L−1 d−1). The biological system was proven to be robust as organic matter conversion efficiency into VFAs increased from 0.30 ± 0.02 COD-VFAs/CODin at 3 g COD L−1 d−1 to 0.37 ± 0.02 COD-VFAs/CODin at 12 g COD L−1d−1. Even though, the hydrolytic step was similar for all studied scenario sCOD/tCOD = 0.52–0.58), the highest OLR (15 g COD L−1 d−1) did not show any further increase in VFAs conversion (0.29 ± 0.01 COD-VFAs/CODin). This fact suggested acidogenesis inhibition at 15 g COD L−1d−1. Butyric (23–32%), acetic (19–26%) and propionic acids (11–17%) were the most abundant bioproducts. Population dynamics analysis revealed microbial specialization, with a high presence of Firmicutes followed by Bacteroidetes. In addition, this investigation showed the microbial adaptation of Euryarchaeota species at the highest OLR (15 g COD L−1d−1), evidencing one of the main challenges in VFAs production (out-competition of archaea community to avoid product consumption). Stepwise OLR increase can be regarded as a tool to promote VFAs productions. However, acidogenic inhibition was reported at the highest OLR instead of the traditional hydrolytic barriers. The operational conditions imposed together with the high VFAs and ammonium concentrations might have affected the system yields. The relative abundance of Firmicutes (74%) and Bacteroidetes (20%), as main phyla, together with the reduction of Euryarchaeota phylum (0.5%) were found the best combination to promote organic matter conversion into VFAs.

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Influence of hydrothermal pretreatment conditions, typology of anaerobic digestion system, and microbial profile in the production of volatile fatty acids from olive mill solid waste

Journal of Environmental Chemical Engineering ◽

10.1016/j.jece.2021.105055 ◽

2021 ◽

Vol 9 (2) ◽

pp. 105055

Author(s):

Yasmim Arantes da Fonseca ◽

Nayara Clarisse Soares Silva ◽

Adonai Bruneli de Camargos ◽

Silvana de Queiroz Silva ◽

Hector Javier Luna Wandurraga ◽

...

Keyword(s):

Fatty Acids ◽

Anaerobic Digestion ◽

Solid Waste ◽

Volatile Fatty Acids ◽

Hydrothermal Pretreatment ◽

Microbial Profile ◽

Olive Mill Solid Waste ◽

Pretreatment Conditions ◽

Olive Mill

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Timing of biochar dosage for anaerobic digestion treating municipal leachate: Altered conversion pathways of volatile fatty acids

Bioresource Technology ◽

10.1016/j.biortech.2021.125283 ◽

2021 ◽

pp. 125283

Author(s):

To-Hung Tsui ◽

Le Zhang ◽

Ee Yang Lim ◽

Jonathan T.E. Lee ◽

Yen Wah Tong

Keyword(s):

Fatty Acids ◽

Anaerobic Digestion ◽

Volatile Fatty Acids

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Increasing 2 -Bio- (H2 and CH4) production from food waste by combining two-stage anaerobic digestion and electrodialysis for continuous volatile fatty acids removal

Waste Management ◽

10.1016/j.wasman.2021.05.006 ◽

2021 ◽

Vol 129 ◽

pp. 20-25

Author(s):

Gamal K. Hassan ◽

Rhys Jon Jones ◽

Jaime Massanet-Nicolau ◽

Richard Dinsdale ◽

M.M. Abo-Aly ◽

...

Keyword(s):

Fatty Acids ◽

Anaerobic Digestion ◽

Food Waste ◽

Volatile Fatty Acids ◽

Two Stage ◽

Ch4 Production

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Wastewater fermentation and nutrient removal in sequencing batch reactors

Water Science & Technology ◽

10.2166/wst.1998.0061 ◽

1998 ◽

Vol 38 (1) ◽

pp. 255-264 ◽

Cited By ~ 4

Author(s):

Germán Cuevas-Rodríguez ◽

Óscar González-Barceló ◽

Simón González-Martínez

Keyword(s):

Activated Sludge ◽

Volatile Fatty Acids ◽

Organic Load ◽

Batch Reactors ◽

Sequencing Batch Reactors ◽

Organic Loading ◽

Nitrogen And Phosphorus ◽

Loading Rates ◽

Average Value ◽

Experimental Runs

This research project was conducted to analyze the performance of a SBR reactor when being fed with anaerobically fermented wastewater. Important was to determine the capacity of the system to remove nitrogen and phosphorus. Two SBR reactors, each one with a volume of 980 liters, were used: one used as fermenter and the other as activated sludge SBR. Using 8-hour cycles, the reactors were operated and studied during 269 days. The fermenter produced an effluent with an average value of 223±24 mg/l of volatile fatty acids. The activated sludge SBR was tested under 3 organic loading rates of 0.13, 0.25, and 0.35 kgCODtotal/kgTSS·d. For the three tested organic loading rates, PO4-P concentrations under 1.1 mg/l and COD between 37 and 38 mg/l were consistently achieved. Exceptionally high NH4-N influent values were measured during the time of the experimentation with the organic load of 0.25 kgCODtotal/kgTSS·d, not reaching in this case full nitrification. Denitrification was observed during the fill phase in every cycle. SVI values between 40 and 70 were determined during the experimental runs.

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