Patterns of Hydrogen in Biogas from the Anaerobic Digestion of Milk-Sugars

Concentrations of hydrogen (1-1000 vpm) in the biogas from a laboratory-scale anaerobic digester, fed with (70 g/l) reconstituted skimmed milk as substrate, were intensively monitored to determine whether hydrogen could provide a useful new alarm/loading indicator for the anaerobic digestion process. With fast-fermenting substrates such as milk-sugars it proved to be a very sensitive event-marker, producing small ripples in time with operation of the digester feed pump as well as larger pulses caused by chloroform toxicity. Scavenging of hydrogen by lithotropic methanogens appeared to promote the fermentation of sugars directly to acetate, bypassing both the formation and subsequent breakdown of higher acids, a feature that is likely to prove peculiar to methanogenic and sulphate-reducing fermentations.

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Designing of lab-scale anaerobic digester equipped with maxblend impeller to evaluate effect of mixing on anaerobic digestion

International Journal of Engineering and Management Sciences ◽

10.21791/ijems.2019.1.50. ◽

2019 ◽

Vol 4 (1) ◽

pp. 404-413

Author(s):

Singh Buta ◽

Zoltán Szamosi ◽

Zoltán Siménfalvi

Keyword(s):

Anaerobic Digestion ◽

Anaerobic Digester ◽

Gas Composition ◽

Operational Parameters ◽

Biogas Yield ◽

Anaerobic Digestion Process ◽

Digestion Process ◽

Mixing Intensity ◽

Enhance Efficiency ◽

Gas Volume

Operational parameters can be easily controlled at lab scale experiments for an anaerobic digestion process. Our aim is to design a lab-scale digester equipped with an impeller to investigate how the geometry of impeller and different mixing modes effect the biogas yield of digester. Further, the methods of measuring the gas volume, gas composition, mixing intensity, torque, temperature are discussed in this article. The assembling of 4 liters digester is described which can be operated at various operating parameters which control the anaerobic digestion process. Mixing is very important to enhance efficiency of an anaerobic digester. To attain mixing Maxblend impeller is used in this lab-scale digester due to its better performance for mixing and power consumption. Various design consideration has been described.

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An Investigation of Impact of Iron and Aluminium Addition on the Anaerobic Digestion Process

Linnaeus Eco-Tech ◽

10.15626/eco-tech.2010.059 ◽

2017 ◽

pp. 558-563

Author(s):

Svetlana Ofverstrom ◽

Ieva Sapkaite ◽

Regimantas Dauknys

Keyword(s):

Wastewater Treatment ◽

Anaerobic Digestion ◽

Activated Sludge ◽

Wastewater Treatment Plant ◽

Treatment Plant ◽

Anaerobic Digester ◽

Anaerobic Digestion Process ◽

Digestion Process ◽

Aluminium Addition ◽

The Impact

In this study, the impact of iron and aluminium salts addition on anaerobic digestion process was investigated. Mixture of primary and activated sludge collected at Vilnius wastewater treatment plant in Lithuania was digested under laboratory conditions by using anaerobic digester (W8, Amfield, UK). To compare the relative digestibility of iron-dosed (Fe-dosed)and aliuminium-iron-dosed (Al-Fe-dosed) sludge with un-dosed sludge three continuous experiments were made. Results showed that iron and aliuminium negatively impacted anaerobic digestion process by reducing the volume of biogas produced. Fe-dosed sludge produced 20-50% less biogas and Al-Fe-dosed sludge produced 30-40% less biogas in comparison to the same un-dosed sludge. VS destruction decreased during dosing of Fe or/and Al salt. Biogas composition was not measured during the experiments.

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Pilot-scale Anaerobic Digestion of Food Waste: Evaluation on the Stability, Methane Production, and Kinetic Analysis

10.21203/rs.3.rs-771721/v1 ◽

2021 ◽

Author(s):

Farizah Fadzil ◽

Farihah Fadzil ◽

Amir Fahim Norazman ◽

Roslinda Seswoya

Keyword(s):

Anaerobic Digestion ◽

Kinetic Analysis ◽

Food Waste ◽

Kinetic Studies ◽

Pilot Scale ◽

Logistic Function ◽

Anaerobic Digester ◽

Total Alkalinity ◽

Anaerobic Digestion Process ◽

Digestion Process

Abstract Food waste was massively disposed at landfills daily, and this method is no longer effective in managing waste due to the limited space and environmental issues. An alternative solution was explored in managing the food waste, and anaerobic digestion serve as the best solution. Food waste was digested anaerobically in a lab-scale and pilot-scale anaerobic digester. The performance of a batch pilot-scale anaerobic digestion of food waste, on the other hand, is less documented. The goal of this research is to look into a batch pilot-scale anaerobic digester for food waste, with a focus on methane potential and kinetic studies. A single-stage anaerobic digestion of food waste was carried out with an inoculum to substrate ratio (I/S) of 2.0. A variety of tests were carried out to identify the properties of the food waste and the inoculum employed. Effluent was collected daily for the monitoring process. The pH and volatile fatty acid to total alkalinity ratio (VFA/TA) were monitored daily to ensure that the anaerobic digestion process remained stable. The VFA/TA ratio suggested that the anaerobic digestion process was stable throughout the anaerobic digestion process. The methane accumulation for 26 days monitoring is 463250 mL. The ultimate methane yield of 5103.6 mL CH4/gVS was observed. The maximum removal efficiency for TS, VS, and COD in this investigation was 85.32, 94.15, and 93.52 %, showing that food waste was efficiently decomposed for biomethane conversion. The Modified Gompertz (GM) and Logistic function models were used to conduct the kinetic analysis. The results reveal that the GM model provides a higher R2 value than the logistic function model, thus the GM model is more suited in explaining the performance of the anaerobic digestion process.

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Effect of a Starch-Rich Industrial Wastewater on the Acid-Phase Anaerobic Digestion Process

Water Environment Research ◽

10.2175/106143005x51941 ◽

2005 ◽

Vol 77 (4) ◽

pp. 366-371 ◽

Cited By ~ 9

Author(s):

Panagiotis Elefsiniotis ◽

David G Wareham ◽

Marcus O Smith

Keyword(s):

Anaerobic Digestion ◽

Industrial Wastewater ◽

Anaerobic Digestion Process ◽

Digestion Process

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A Mathematical Model for the Anaerobic Digestion Process Applied to a Mixture of Night Soil and Septic Tank Sludge

Water Science & Technology ◽

10.2166/wst.1986.0295 ◽

1986 ◽

Vol 18 (7-8) ◽

pp. 239-248 ◽

Cited By ~ 2

Author(s):

Sung Ryong Ha ◽

Dwang Ho Lee ◽

Sang Eun Lee

Keyword(s):

Mathematical Model ◽

Anaerobic Digestion ◽

Biomass Concentration ◽

Gas Production ◽

Septic Tank ◽

Volatile Acid ◽

Hydraulic Residence Time ◽

Anaerobic Digestion Process ◽

Digestion Process ◽

Proposed Model

Laboratory scale experiments were conducted to develop a mathematical model for the anaerobic digestion of a mixture of night soil and septic tank sludge. The optimum mixing ratio by volume between night soil and septic tank sludge was found to be 7:3. Due to the high solids content in the influent waste, mixed-liquor volatile suspended solids (MLVSS) was not considered to be a proper parameter for biomass concentration, therefore, the active biomass concentration was estimated based on deoxyribonucleic acid (DNA) concentration in the reactor. The weight ratio between acidogenic bacteria and methanogenic bacteria in the mixed culture of a well-operated anaerobic digester was approximately 3:2. The proposed model indicates that the amount of volatile acid produced and the gas production rate can be expressed as a function of hydraulic residence time (HRT). The kinetic constants of the two phases of the anaerobic digestion process were determined, and a computer was used to simulate results using the proposed model for the various operating parameters, such as BOD5 and volatile acid concentrations in effluent, biomass concentrations and gas production rates. These were consistent with the experimental data.

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