An automated spectrophotometric system for monitoring buffer capacity in anaerobic digestion processes

Jantsch, Tor Gunnar; Mattìasson, Bo

doi:10.1016/j.watres.2004.05.010

Cited by 41 publications

(17 citation statements)

References 11 publications

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“…Volatile fatty acids (VFA) were measured by gas chromatography (Shimazdu 2010). Alkalinity was measured weekly by titration with 0.25N H 2 SO 4 to endpoints of 5.7, 4.3 and 4.0 representing partial (PA), intermediate (IA) and total (TA) alkalinity (Jantsch and Mattiasson, 2004). ) not measured and 2938, for maize and cattle slurry respectively.…”

Section: Methodsmentioning

confidence: 99%

Effect of increasing the organic loading rate on the co-digestion and mono-digestion of cattle slurry and maize

Cornell¹,

Banks

Heaven

2012

Water Science and Technology

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Effect of increasing the organic loading rate on the codigestion and mono-digestion of cattle slurry and maize." Water Science & Technology 66, no. 11 (2012) AbstractCo-digestion of cattle slurry and maize has been shown to have benefits for both, improving the biogas yield of the slurry and stability of digestion of the maize. The effect of increasing the total loading rate from 3 to 6 g VS l -1 day -1 on the co-digestion of cattle slurry and maize, mixed at equal volatile solids volumes, was investigated in laboratory-scale continuously stirred digesters. These were compared to similar digesters evaluating the increase of 1.5 to 3 g VS l -1 day -1 loading rates of slurry and maize digested separately. Compared to mono-digestion of the substrates, where the digestion of maize failed at loading rates greater than 2.5 g VS l -1 day -1, the co-digestion of cattle slurry and maize was feasible at all the loading rates tested with an increase in the volumetric methane yield occurring with loading rate. Even at the lowest rate of loading the addition of equal amount of volatile solids of maize to slurry lead to an increase in volumetric methane yield of 219% Keywords Anaerobic digestion; cattle slurry; co-digestion; kinetics; maize INTRODUCTIONThe storage and use of animal wastes of which the EU-27 produces 1284 million tonnes per year (Holm-Nielsen, 2007) leads to the production of greenhouse gases including methane. Anaerobic digestion is a well-established process that can divert the methane released from animal wastes, including cattle slurry, into a source of bio-energy. Bio-energy production is attractive to farmers as it can supply the energy required by the farm and provide an additional source of income; anaerobic digestion also produces a digestate that can be used as fertiliser. Unfortunately, the digestion of cattle slurry alone yields relatively low amounts of bio-energy in comparison to feedstocks such as energy crops (Weiland, 2006). Crop materials such as maize are therefore added to the slurry in order to improve gas production and thus potential income. The digestion of energy crops alone can also be difficult and co-digestion with cattle slurry can improve the buffering capacity of the system, as has been shown for cosubstrates such as fruit and vegetable waste and slaughterhouse waste (Alvarez and Lidén, 2008;Banks et al., 2010) A possible further benefit is the potential for synergy between the co-substrates which some studies have reported (e.g. Machmüller et al., 2007;Cornell et al., 2008). There is little published work on synergy, however, and the effects are often identified through comparison of results from mono-and co-digestion trials following different methodologies, e.g. batch and semi-continuous. This approach may not provide an accurate picture as it has been shown that batch and semi-continuous trials can produce different results (Callaghan et al., 1998 and1999).

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Section: Methodsmentioning

confidence: 99%

Effect of increasing the organic loading rate on the co-digestion and mono-digestion of cattle slurry and maize

Cornell¹,

Banks

Heaven

2012

Water Science and Technology

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“…The objective in this study was to characterize the microbial community structure and dynamics in a thermophilic process under deteriorative and stable conditions that were induced by acidification and neutralization, respectively. Acidification of the methanogenic bioreactor has been widely understood to be one of the most common problems inducing process deterioration (21,48). The responses of archaeal and bacterial communities to these reactor conditions were investigated using a combination approach of process analyses and molecular ecological techniques, i.e., PCR-mediated single-strand conformation polymorphism (SSCP) based on the 16S rRNA gene, quantitative PCR, and fluorescence in situ hybridization (FISH).…”

mentioning

confidence: 99%

Dynamic Transition of a Methanogenic Population in Response to the Concentration of Volatile Fatty Acids in a Thermophilic Anaerobic Digester

Hori

Haruta

Ueno

et al. 2006

Appl Environ Microbiol

281

131

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In this study, the microbial community succession in a thermophilic methanogenic bioreactor under deteriorative and stable conditions that were induced by acidification and neutralization, respectively, was investigated using PCR-mediated single-strand conformation polymorphism (SSCP) based on the 16S rRNA gene, quantitative PCR, and fluorescence in situ hybridization (FISH). The SSCP analysis indicated that the archaeal community structure was closely correlated with the volatile fatty acid (VFA) concentration, while the bacterial population was impacted by pH. The archaeal community consisted mainly of two species of hydrogenotrophic methanogen (i.e., a Methanoculleus sp. and a Methanothermobacter sp.) and one species of aceticlastic methanogen (i.e., a Methanosarcina sp.). The quantitative PCR of the 16S rRNA gene from each methanogen revealed that the Methanoculleus sp. predominated among the methanogens during operation under stable conditions in the absence of VFAs. Accumulation of VFAs induced a dynamic transition of hydrogenotrophic methanogens, and in particular, a drastic change (i.e., an approximately 10,000-fold increase) in the amount of the 16S rRNA gene from the Methanothermobacter sp. The predominance of the one species of hydrogenotrophic methanogen was replaced by that of the other in response to the VFA concentration, suggesting that the dissolved hydrogen concentration played a decisive role in the predominance. The hydrogenotrophic methanogens existed close to bacteria in aggregates, and a transition of the associated bacteria was also observed by FISH analyses. The degradation of acetate accumulated during operation under deteriorative conditions was concomitant with the selective proliferation of the Methanosarcina sp., indicating effective acetate degradation by the aceticlastic methanogen. The simple methanogenic population in the thermophilic anaerobic digester significantly responded to the environmental conditions, especially to the concentration of VFAs.

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“…For inline use it has the potential to be fouled by biofilm during a long-term detection, especially for high biomass contained wastewater such as anaerobic digester effluent, thereby reducing the reliability of the pH readings. [9] Therefore, periodic recalibration of the pH probe is recommended.…”

Section: Relationship Between Online Ec Detection and Conventional Chmentioning

confidence: 99%

“…More recently, a new spectrophotometric method based on pH indicators has been used for alkalinity measurements in monitoring different anaerobic digester systems. [8,9] Irrespective of whether using stepwise manual injection or an automatic titration system, the introduction of H + ions in the titration methods mentioned above is achieved by addition of acidic solution (titrant) with known concentration and volume. This requires additional chemicals, precise and reliable control system, and regular servicing (e.g.…”

Section: Introductionmentioning

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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An automated spectrophotometric system for monitoring buffer capacity in anaerobic digestion processes

Cited by 41 publications

References 11 publications

Effect of increasing the organic loading rate on the co-digestion and mono-digestion of cattle slurry and maize

Effect of increasing the organic loading rate on the co-digestion and mono-digestion of cattle slurry and maize

Dynamic Transition of a Methanogenic Population in Response to the Concentration of Volatile Fatty Acids in a Thermophilic Anaerobic Digester

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

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