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1.
Biogas production from brewery yeast in an EGSB reactor
Romana Marinšek-Logar, Matej Oset, Miran Klemenčič, Milenko Roš, Gregor Drago Zupančič, 2016, professional article

Abstract: Experience over a five-year period of full throughput using anaerobic co-digestion of brewery yeast for biogas production is described in this contribution. The brewery, with a total amount of available yeast (0.7 v/v %), had a 26.2 % increase in COD load and a 38.5 % increase in biogas production resulting in an increase in the biomethane/natural gas substitution ratio in the brewery from 10 % to 16 %.
Found in: ključnih besedah
Keywords: Anaerobic digestion, biogas production, brewery yeast, brewery wastewater, EGSB
Published: 21.04.2016; Views: 3885; Downloads: 0
.pdf Fulltext (267,88 KB)

2.
Anaerobic digestion of brewery spent grain as a mono-substrate in a two-stage anaerobic digestion using solid-state digestion reactor and granulated biomass reactor
Marina Tišma, Bruno Zelić, Romana Marinšek Logar, Mario Panjicko, Gregor Drago Zupančič, 2016, published scientific conference contribution (invited lecture)

Abstract: Anaerobic digestion of brewery spent grain as a mono-substrate was studied. Anaerobic digestion was phase separated in solid state anaerobic digestion reactor, where mostly microbiological hydrolysis and acidogenesis and granular biomass reactor where mostly methanogenesis was performed. The overall process exhibited total solids degradation efficiency between 73.6 and 80.4%. Average specific biogas production was 424±36 L/kg, whereas biomethane production was 230±34 L/kg of brewery spent grain total solids. Granular biomass after adaptation exhibited stabile operation at C-N ratios as low as 0.2 – 0.3, which is rare in anaerobic digestion. P-cresol as a degradation product was present in concentrations up to 45 mg/L and during the process successfully degraded. The excellent adaptability of the granular biomass is confirmed by 67% shift in bacterial and a 32% shift in archaeal community structure in granular biomass reactor after 198 days of successful operation.
Found in: ključnih besedah
Summary of found: ...efficiency between 73.6 and 80.4%. Average specific biogas production was 424±36 L/kg, whereas biomethane production...
Keywords: Anaerobic digestion, biogas production, brewery spent grain, microbial biomass, p-cresol degradation, solid state anaerobic digestion
Published: 21.10.2016; Views: 3521; Downloads: 0
.pdf Fulltext (968,03 KB)

3.
Biogas Production from Brewer’s Yeast Using an Anaerobic Sequencing Batch Reactor
Gregor Drago Zupančič, Mario Panjicko, Bruno Zelić, 2017, original scientific article

Abstract: Renewable energy sources are becoming increasingly important in the beverage and food industries. In the brewing industry, a significant percentage of the used raw materials finishes the process as secondary resource or waste. The research on the anaerobic digestion of brewer’s yeast has been scarce until recent years. One of the reasons for this is its use as a secondary resource in the food industry and as cattle feed. Additionally, market value of brewer’s yeast is higher than its energy value. Due to the increase of energy prices, brewer’s yeast has become of interest as energy substrate despite its difficult degradability in anaerobic conditions. The anaerobic co-digestion of brewer’s yeast and anaerobically treated brewery wastewater was studied using a pilot-scale anaerobic sequencing batch reactor (ASBR) seeded with granular biomass. The experiments showed very good and stable operation with an organic loading rate of up to 8.0 kg/(m3·day), and with a maximum achieved organic loading rate of 13.6 kg/(m3·day) in a single cycle. A specific biogas productivity of over 0.430 m3/kg of the total chemical oxygen demand (COD) inserted, and total COD removal efficiencies of over 90 % were achieved. This study suggests that the brewer’s yeast can be successfully digested in an ASBR without adverse effects on the biogas production from brewer's yeast/wastewater mixtures of up to 8 % (by volume). By using the brewer's yeast in the ASBR process, the biogas production from brewery wastewater could be increased by 50 %.
Found in: ključnih besedah
Keywords: anaerobic digestion, ASBR, biogas, brewer’s yeast
Published: 15.06.2017; Views: 2939; Downloads: 0
.pdf Fulltext (728,20 KB)

4.
Biogas production from brewery spent grain as a mono-substrate in a two-stage process composed of solid-state anaerobic digestion and granular biomass reactors
Mario Panjicko, Gregor Drago Zupančič, Romana Marinšek-Logar, Lijana Fanedl, Marina Tišma, Bruno Zelić, 2017, original scientific article

Abstract: Anaerobic digestion of brewery spent grain as a mono-substrate was studied. Brewery spent grain is a substrate consisting largely of cellulose, hemicellulose and lignin, which are difficult to degrade anaerobically, mostly due to the presence of degradation products, such as phenolic compounds, which cause process inhibition. Therefore, a two-stage system was used for anaerobic digestion. Anaerobic digestion was phase separated in a solid-state anaerobic digestion reactor, where microbiological hydrolysis and acidogenesis occurred and in a granular biomass reactor where mostly methanogenesis was performed. The overall process exhibited total solids degradation efficiency between 75.9 and 83.0 %. Average specific biogas production was 414±32 L/kg, whereas biomethane production was 224±34 L/kg of added total solids. Granular biomass after adaptation exhibited stable operation at substrate C/N ratios in range 0.16 – 4.68. p-cresol was present in concentrations up to 45 mg/L and during the process was successfully degraded by granular biomass. The excellent adaptability of granular biomass was confirmed by 68.2 % shift in bacterial and a 31.8 % shift in archaeal community structure in a granular biomass reactor. The structure of the bacterial community from granular biomass reactor and solid-state anaerobic digestion reactor remained 79.4 % similar at the end of the experiment, whereas archaeal community was only 31.6 % similar. The process exhibited stable operation for 198 days, which shows that brewery spent grain can be successfully anaerobically digested and used for biogas production.
Found in: ključnih besedah
Keywords: biogas production, brewery spent grain, C/N ratio, dry digestion, microbial biomass, solid-state anaerobic digestion
Published: 18.08.2017; Views: 2669; Downloads: 0
.pdf Fulltext (2,27 MB)

5.
Anaerobic treatment of excess yeast and waste ethanol from alcohol free beer production for increase of renewable energy use in brewing industry
Goran Lukić, Mario Panjicko, Gregor Drago Zupančič, 2020, published scientific conference contribution

Abstract: In the presented paper we have investigated how large quantities of excess yeast and periodical releases of waste ethanol influence the operation of the anaerobic treatment process in a UASB reactor. The process was tested in a pilot-scale reactor with a design organic load of 16.0 kg/m3/day of COD. Through various stages of the experiment, several possible scenarios were tested, excess yeast was added continuously with concentrations up to 3 vol. %, whereas waste ethanol was added in batches of up to 0.8 % of daily volume load several days a week. The intent was to test real conditions in the treatment process. The whole experiment lasted for 77 days, where the maximum organic load of 24.72 kg/m3/day was successfully achieved with no adverse effects on the efficiency of the reactor performance although it significantly surpassed the design load. The COD efficiency at maximum OLR was 83.1 %, whereas the average was 88.0 %. The average biogas production rate increased from 2,044 m3/m3/day to 4.927 m3/m3/day. The microbial community structure analysis showed significant shifts only in the archaeal community (25 – 30 %) as a good adaptation to the addition of substrates. Monitoring the model brewery in applying the addition of yeast and ethanol to the wastewater treatment showed a 110 % increase in biomethane production. The consequence of the increased biomethane production is that the natural gas substitute ratio could be increased from the current average of 10.7 % to potentially 20.1 %, which is a substantial step towards the goal of renewable energy use.
Found in: ključnih besedah
Summary of found: ...the average was 88.0 %. The average biogas production rate increased from 2,044 m3/m3/day to...
Keywords: anaerobic digestion, biogas, brewery yeast, renewable energy, waste ethanol
Published: 10.06.2021; Views: 467; Downloads: 3
.pdf Fulltext (825,82 KB)
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6.
An economic analysis of biomass potential as an opportunity to increase the share of biogas production for energy purposes in Slovenia
Stefan Dabižljević, 2021, master's thesis

Abstract: One of the biggest global problems, the solution of being put in front of the scientists around the world, is endangering the environment. To preserve it, the transition from non-renewable to renewable energy sources is a rational and necessary solution. One of the energy sources with great potential in the future is biomass. In the master’s thesis, we have studied the economic analysis of the possibility of obtaining energy from biogas in Slovenia for the production of which biomass is used. For the study to be successful, it was necessary to analyse the situation in the field of renewable energy sources and biogas in the European Union and Slovenia to obtain a general picture for further analysis. By analysing the available data from previous years, we gained insight into the situation in the given area. The master’s thesis aims to show that although Slovenia has been facing the problem of a decreasing number of biogas power plants for years, the implementation of a system for obtaining energy from biogas is an economically and environmentally viable investment. The economic analysis was done for a 1 MW plant. The choice of plant size and power was made based on the Kepner-Tregoe method and the method of comparing alternatives. For the project duration of 30 years, through cash flows, as well as through various economic indicators, such as the presentation of loan calculations with a certain interest rate, internal rate of return, repayment period method, present project value, etc., the economic side of the investment is presented, which aims to show the profitability of the project.
Found in: ključnih besedah
Keywords: Renewable energy sources, biomass, biogas, economic analysis, investment, project
Published: 07.09.2021; Views: 393; Downloads: 20
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