Propionic to acetic acid ratios in overloaded anaerobic digestion

Marchaim, U.; Krause, Carsten

doi:10.1016/0960-8524(93)90031-6

Cited by 140 publications

(75 citation statements)

References 15 publications

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“…In the own experiment, the ratio decreased to less than one on day 19, when the overacidification was already completed and the EWI-VFA/Ca had already indicated an impending process failure 6 days before. Marchaim and Krause (1993) found the increase of the concentration ratio of propionic to acetic acid independent of a critical value to be a satisfactory indicator for the beginning of an organic overload. In the own experiment, the ratio showed no significant increase before day 16.…”

Section: Provoked Accumulation Of Fatty Acids By Overloading (1) Witmentioning

confidence: 99%

Early warning indicators for process failure due to organic overloading by rapeseed oil in one-stage continuously stirred tank reactor, sewage sludge and waste digesters

Kleyböcker

Liebrich

Verstraete³

et al. 2012

Bioresource Technology

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Originally published as:Kleyböcker, A., Liebrich, M., Verstraete, W., Kraume, M., Würdemann, H. (2012) ABSTRACTEarly warning indicators for process failures were investigated to develop a reliable method to increase the production efficiency of biogas plants. Organic overloads by the excessive addition of rapeseed oil were used to provoke the decrease in the gas production rate. Besides typical monitoring parameters, as pH, methane and hydrogen contents, biogas production rate and concentrations of fatty acids; carbon dioxide content, concentrations of calcium and phosphate were monitored. The concentration ratio of volatile fatty acids to calcium acted as an early warning indicator (EWI-VFA/Ca). The EWI-VFA/Ca always clearly and reliably indicated a process imbalance by exhibiting a two-to threefold increase 3 to 7 days before the process failure occurred. At this time, it was still possible to take countermeasures successfully. Furthermore, increases in phosphate concentration and in the concentration ratio of phosphate to calcium also indicated a process failure, in some cases, even earlier than the EWI-VFA/Ca.

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Section: Provoked Accumulation Of Fatty Acids By Overloading (1) Witmentioning

confidence: 99%

Early warning indicators for process failure due to organic overloading by rapeseed oil in one-stage continuously stirred tank reactor, sewage sludge and waste digesters

Kleyböcker

Liebrich

Verstraete³

et al. 2012

Bioresource Technology

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“…The propionic/acetic acid ratio that was presented by Marchaim and Krause [4] as "a reliable indicator for impending failure" showed a rapid increase in the very early over-acidification phase from 0 to 0.21 (Fig. 3b).…”

Section: Process Upset Indicatorsmentioning

confidence: 99%

“…Kleyböcker et al [1] introduced three EWIs for overacidification in AD processes: EWI-VFA/Ca, EWI-PO 4 / Ca and EWI-PO 4 . The authors developed these indicators and demonstrated their predictive ability in an AD system with sewage sludge and rapeseed oil as substrates [1,26].…”

Section: Process Upset Indicatorsmentioning

confidence: 99%

“…Over-acidification occurs mainly as a result of an overload of the biogas system due to either high organic loading rates [1,4] or the occurrence of inhibitors in the digester such as ammonia, sulfide, heavy metals, or substituted phenolic compounds [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…With regard to foam formation, a test set for the estimation of the foaming tendency of substrates [15] has been developed recently. Several abiotic factors were identified to be able to serve as early warning indicators (EWIs) for over-acidification: the total or individual concentration of volatile fatty acids (VFA) [16], the propionic/acetic acid ratio [4], the VFA/ alkalinity ratio (also known as VFA/TIC) [17,18], the VFA/Ca ratio, the phosphate concentration, the PO 4 /Ca ratio [1], phenylacetic acid [19], as well as biogas production [16] and biogas composition, especially the CH 4 yield [20] and hydrogen concentration [21].…”

Section: Introductionmentioning

confidence: 99%

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Process upsets in a full-scale anaerobic digestion bioreactor: over-acidification and foam formation during biogas production

Moeller

Zehnsdorf

2016

Energ Sustain Soc

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Background: Biogas plays a worthwhile role as a renewable, storable energy source. Anaerobic digestion (AD) is the core process in biogas production. The two most common process upsets that occur during this biotechnological process in practice are over-acidification and foam formation. Several research projects have been carried out so far to identify the causes of these upsets and to develop early warning indicators. However, the relevant laboratory resultshave not yet been verified in practice. Accordingly, the aim of this work was to study the practical application of the published tools in the case of a full-scale biogas plant. Methods: A full-scale AD plant utilizing cattle manure and energy crops was sampled over a period of 12 weeks. During this time, over-acidification and foam formation occurred in the primary digester. Results: The sum of acetate, propionate and butyrate (VFA S ) and the ratios of VFA S to magnesium (VFA S /Mg), calcium (VFA S /Ca), and phosphorus (VFA S /P) were found to be good predictive tools to identify over-acidification for the given AD system. Their values increased by factors of 6 (VFA S /Mg and VFA S /Ca) and 13 (VFA S , VFA S /P) in the early overacidification phase. In contrast, the VFA/TIC ratio, which is a common indicator in practice, increased only by a factor of 2 during this phase. An ammonium-nitrate-urea solution proved to be an effective agent for foam suppression when sugar beet was used as a substrate. Its application showed no negative effect on the daily electricity production and the achieved long-term foam elimination. Conclusions: Several parameters were verified to be able to serve as an early warning indicator of over-acidification, but not one was found to be able to serve as an early warning indicator of foam formation in AD. Further research is needed to identify parameters with predictive potential for indicating foaming in AD.

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Screening Organic Compounds in Urban Wastewater Using a Hyphenated System and NMR Pattern Recognition

Filho

Silva

Ferreira

2017

eMagRes

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Propionic to acetic acid ratios in overloaded anaerobic digestion

Cited by 140 publications

References 15 publications

Early warning indicators for process failure due to organic overloading by rapeseed oil in one-stage continuously stirred tank reactor, sewage sludge and waste digesters

Early warning indicators for process failure due to organic overloading by rapeseed oil in one-stage continuously stirred tank reactor, sewage sludge and waste digesters

Process upsets in a full-scale anaerobic digestion bioreactor: over-acidification and foam formation during biogas production

Screening Organic Compounds in Urban Wastewater Using a Hyphenated System and NMR Pattern Recognition

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