Dissolved hydrogen concentration as an on-line control parameter for the automated operation and optimization of anaerobic digesters

Cord‐Ruwisch, Ralf; Mercz, Tom I.; Hoh, Choon-Yee; Strong, G.E.

doi:10.1002/(sici)1097-0290(19971220)56:6<626::aid-bit5>3.0.co;2-p

Cited by 67 publications

(36 citation statements)

References 26 publications

(42 reference statements)

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“…Hydrogen in digester 57.5°C2 accumulated to a concentration of approximately 11.4 Pa, only slightly higher than the previously published upper limit for efficient metabolism of propionate. Such concentrations of hydrogen in themselves are unlikely to result in a substantial buildup of Pr -, however past studies focused on the development of online early warning systems for digester upset used hydrogen partial pressures as low a 6.5 Pa to indicate potential onset of overload conditions (CordRuwisch et al, 1997).…”

Section: Resultsmentioning

confidence: 99%

The effect of temperature on the performance and stability of thermophilic anaerobic digestion

Wilson

Murthy

Yuan

et al. 2008

Water Science and Technology

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Sustainable operation of an anaerobic sewage sludge digester requires the effective shuttling of carbon from complex organic material to methane gas. The accumulation of intermediates and metabolic products such as volatile fatty acids and hydrogen gas not only reveal inefficiency within the digestion process, but can be detrimental to reactor operation at sufficiently high levels. Eight anaerobic digesters (1 mesophilic and 7 thermophilic) were operated in order to determine the effect of steady-state digestion temperature on the operational stability and performance of the digestion process. Replicate reactors operated at 57.5°C, the highest temperature studied, were prone to accumulation of volatile fatty acids (4052 and 3411 mg/L as acetate) and gaseous hydrogen. Reactors operated at or below 55°C showed no such accumulation of intermediate metabolites. Overall methanogenesis was also greatly reduced at 57.5°C (0.09 L CH4/g VS fed) versus optimal methane formation at 53°C (0.40 L CH4/ g VS fed). Microbial community assessment and free energy calculations suggest that the accumulation of fatty acids and hydrogen, and relatively poor methanogenic performance at 57.5°C are likely due to temperature limitations of thermophilic aceticlastic methanogens.Keywords: Acetate; methane; hydrogen; propionate; temperature; thermophilic anaerobic digestion INTRODUCTION Stringent pathogen regulations required for the land application of domestic wastewater biosolids have revitalized interest in thermophilic anaerobic digestion. Since biological activity at these temperatures requires specialized organisms equipped with thermostable cell components and enzymes, thermophilic anaerobic digestion has recently been recognized as holistically unique biological process, rather than a close variation of mesophilic anaerobic digestion. As such, much of the fundamental discussion regarding anaerobic digestion technology, keeping mesophilic anaerobic digestion in mind, is inadequate for the development of a thorough understanding of the design parameters and operational variables that greatly affect thermophilic performance.

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Section: Resultsmentioning

confidence: 99%

The effect of temperature on the performance and stability of thermophilic anaerobic digestion

Wilson

Murthy

Yuan

et al. 2008

Water Science and Technology

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“…The maximum partial pressures of H 2 under which syntrophic propionate and acetate oxidisation can take place are in the same range (Schink, 1997) and as there is no accumulation of acetate its oxidation does not appear to be inhibited. It is possible that formate is the trigger for inhibition, but the concentration range at which this occurs has rarely been studied (Schink, 1997), whereas the partial pressure at which H 2 has an effect is well known (Cord-Ruwisch et al, 1997). Although most microorganisms involved in interspecies electron transfer can exchange hydrogen with formate and vice versa, and the standard redox potential of both electron carrier systems (H + /H 2 and CO 2 /formate) is nearly identical (Thauer et al, 2008), the conversion between them requires formate dehydrogenase (FDH) which has been reported to require Se, Mo and W (Andreesen and Ljungdahl, 1973;de Bok et al, 2003;Worm et al, 2011).…”

Section: 2mentioning

confidence: 99%

Trace element requirements for stable food waste digestion at elevated ammonia concentrations

Banks

Zhang

Jiang

et al. 2012

Bioresource Technology

318

162

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The work investigated why anaerobic digesters treating food waste and operating at high ammonia concentrations suffer from propionic acid accumulation which may result in process failure. The results showed deficiency of selenium, essential for both propionate oxidation and syntrophic hydrogenotrophic methanogenesis, leads to this while supplementation allows operation at substantially higher organic loading rates (OLR). At high loadings cobalt also becomes limiting, due to its role either in acetate oxidation in a reverse Wood-Ljungdahl pathway or in hydrogenotrophic methanogenesis. Population structure analysis using fluorescent in-situ hybridisation showed only hydrogenotrophic methanogens. Critical Se and Co concentrations were established as 0.16 and 0.22 mg kg -1 fresh matter feed at moderate loading. At this dosage the OLR could be raised to 5 g VS l -1 day -1 giving specific and volumetric biogas productions of 0.75 m 3 kg -1 VS added and 3.75 STP m 3 m -3 day -1 , representing a significant increase in process performance and operational stability.

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“…Therefore, the instability caused by VFAs accumulation in the anaerobic process cannot be determined by the traditional TA value For anaerobic digestion control, monitoring the hydrogen partial pressure in the gas or solution can be used as a potential online rapid indicator of digester stress or overloading. [15] Impending digester failure due to acidification could be most reliably diagnosed by the combination of hydrogen level and the ratio of PA and IA. However, not all digester perturbations can be reflected by the change of hydrogen level, the online measurement of alkalinity indeed can be made at regular intervals.…”

Section: Online Titration Curve Of Real Municipal Wastewater and Anaementioning

confidence: 99%

Automatic online buffer capacity (alkalinity) measurement of wastewater using an electrochemical cell

Cheng

Charles

Cord‐Ruwisch

2016

Environmental Technology

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The use of an automatic online electrochemical cell (EC) for measuring the buffer capacity of wastewater is presented. pH titration curves of different solutions (NaHCO 3 , Na 2 HPO 4 , real municipal wastewater, and anaerobic digester liquid) were obtained by conventional chemical titration and compared to the online EC measurements. The results show that the pH titration curves from the EC were comparable to that of the conventional chemical titration. The results show a linear relationship between the response of the online EC detection system and the titrimetric partial alkalinity and total alkalinity of all tested samples. This suggests that an EC can be used as a simple online titration device for monitoring the buffer capacity of different industrial processes including wastewater treatment and anaerobic digestion processes.

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Dissolved hydrogen concentration as an on-line control parameter for the automated operation and optimization of anaerobic digesters

Cited by 67 publications

References 26 publications

The effect of temperature on the performance and stability of thermophilic anaerobic digestion

The effect of temperature on the performance and stability of thermophilic anaerobic digestion

Trace element requirements for stable food waste digestion at elevated ammonia concentrations

Automatic online buffer capacity (alkalinity) measurement of wastewater using an electrochemical cell

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