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Prem EM, Markt R, Wunderer M, Wagner AO. Meso- and thermophilic posttreatment of press water coming from a thermophilic municipal solid waste digester. Biotechnol Bioeng 2024; 121:266-280. [PMID: 37902646 PMCID: PMC10953027 DOI: 10.1002/bit.28577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/02/2023] [Accepted: 10/10/2023] [Indexed: 10/31/2023]
Abstract
An efficient biogas production out of organic (waste) materials is important to contribute to a carbon-neutral future. In this study, thermophilic press water (PW) coming from an organic fraction of the municipal solid waste digester was further digested in a thermo- and mesophilic posttreatment approach using two semicontinuous 14 L digesters. The results showed that the PW can still have considerable high biogas potential-at least during the touristic high season in central Europe. The change in temperature led to an increase in volatile fatty acid concentrations and a decrease in biogas production in the mesophilic approach in the first days. However, the losses in biogas production at the beginning could be compensated thus there were no considerable differences in biogas production between thermo- and mesophilic posttreatment at the end of incubation. This can most probably be contributed to a change in the microbial community, and potentially problematic intermediates like valerate could be better degraded in the mesophilic reactor. Especially the abundance of representatives of the phylum Bacteroidota, like Fermentimonas spp., increased during mesophilic anaerobic digestion.
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Affiliation(s)
- Eva Maria Prem
- Department of MicrobiologyUniversität InnsbruckInnsbruckAustria
| | - Rudolf Markt
- Department of MicrobiologyUniversität InnsbruckInnsbruckAustria
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Prem EM, Schwarzenberger A, Markt R, Wagner AO. Effects of phenyl acids on different degradation phases during thermophilic anaerobic digestion. Front Microbiol 2023; 14:1087043. [PMID: 37089573 PMCID: PMC10113666 DOI: 10.3389/fmicb.2023.1087043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/06/2023] [Indexed: 04/08/2023] Open
Abstract
Aromatic compounds like phenyl acids (PA) can accumulate during anaerobic digestion (AD) of organic wastes due to an increased entry of lignocellulose, secondary plant metabolites or proteins, and thermodynamic challenges in degrading the benzene ring. The effects of aromatic compounds can be various – from being highly toxic to be stimulating for methanogenesis – depending on many parameters like inoculum or molecular characteristics of the aromatic compound. To contribute to a better understanding of the consequences of PA exposure during AD, the aim was to evaluate the effects of 10 mM PA on microbial communities degrading different, degradation phase–specific substrates in thermophilic batch reactors within 28 days: Microcrystalline cellulose (MCC, promoting hydrolytic to methanogenic microorganisms), butyrate or propionate (promoting syntrophic volatile fatty acid (VFA) oxidisers to methanogens), or acetate (promoting syntrophic acetate oxidisers to methanogens). Methane production, VFA concentrations and pH were evaluated, and microbial communities and extracellular polymeric substances (EPS) were assessed. The toxicity of PA depended on the type of substrate which in turn determined the (i) microbial diversity and composition and (ii) EPS quantity and quality. Compared with the respective controls, methane production in MCC reactors was less impaired by PA than in butyrate, propionate and acetate reactors which showed reductions in methane production of up to 93%. In contrast to the controls, acetate concentrations were high in all PA reactors at the end of incubation thus acetate was a bottle-neck intermediate in those reactors. Considerable differences in EPS quantity and quality could be found among substrates but not among PA variants of each substrate. Methanosarcina spp. was the dominant methanogen in VFA reactors without PA exposure and was inhibited when PA were present. VFA oxidisers and Methanothermobacter spp. were abundant in VFA assays with PA exposure as well as in all MCC reactors. As MCC assays showed higher methane yields, a higher microbial diversity and a higher EPS quantity and quality than VFA reactors when exposed to PA, we conclude that EPS in MCC reactors might have been beneficial for absorbing/neutralising phenyl acids and keeping (more susceptible) microorganisms shielded in granules or biofilms.
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Affiliation(s)
- Eva Maria Prem
- Department of Microbiology, Universität Innsbruck, Innsbruck, Austria
| | | | - Rudolf Markt
- Department of Microbiology, Universität Innsbruck, Innsbruck, Austria
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Choi G, Kim H, Lee C. Long-term monitoring of a thermal hydrolysis-anaerobic co-digestion plant treating high-strength organic wastes: Process performance and microbial community dynamics. BIORESOURCE TECHNOLOGY 2021; 319:124138. [PMID: 32980668 DOI: 10.1016/j.biortech.2020.124138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/12/2020] [Accepted: 09/13/2020] [Indexed: 06/11/2023]
Abstract
Two parallel anaerobic digesters (8500 m3 capacity each), combined with thermal hydrolysis (TH) pretreatment, co-digesting dewatered sewage sludge, dewatered human feces, and food wastewater were monitored over a 12-month period from start-up to explore the feasibility of field application of the combined process. The waste mixtures before and after pretreatment and the feed and digestate of each digester were taken semimonthly (i.e., 48 samples in total) for analysis of the feed characteristics, process parameters, and digester microbial community structure. The TH pretreatment proved effective in improving the bioavailability of the waste mixture. The solubilization efficiency tended to increase with the particulate organic fraction in the raw mixture. Although fluctuations in the feed characteristics and loading significantly influenced the process and microbial behaviors, the digesters maintained stable performance during the study period. Our results demonstrate that the TH-anaerobic digestion process can achieve an effective and robust treatment of the waste mixture.
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Affiliation(s)
- Gyucheol Choi
- School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea
| | - Hanwoong Kim
- School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea
| | - Changsoo Lee
- School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea.
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Lackner N, Wagner AO, Illmer P. Effect of sulfate addition on carbon flow and microbial community composition during thermophilic digestion of cellulose. Appl Microbiol Biotechnol 2020; 104:4605-4615. [PMID: 32219464 PMCID: PMC7190589 DOI: 10.1007/s00253-020-10546-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 01/20/2020] [Accepted: 03/15/2020] [Indexed: 01/04/2023]
Abstract
Substrates with high sulfate levels pose problems for biogas production as they allow sulfate reducing bacteria to compete with syntrophic and methanogenic members of the community. In addition, the end product of sulfate reduction, hydrogen sulfide, is toxic and corrosive. Here we show how sulfate addition affects physiological processes in a thermophilic methanogenic system by analyzing the carbon flow and the microbial community with quantitative PCR and amplicon sequencing of the 16s rRNA gene. A sulfate addition of 0.5 to 3 g/L caused a decline in methane production by 73-92%, while higher sulfate concentrations had no additional inhibitory effect. Generally, sulfate addition induced a shift in the composition of the microbial community towards a higher dominance of Firmicutes and decreasing abundances of Bacteroidetes and Euryarchaeota. The abundance of methanogens (e.g., Methanoculleus and Methanosarcina) was reduced, while sulfate reducing bacteria (especially Candidatus Desulforudis and Desulfotomaculum) increased significantly in presence of sulfate. The sulfate addition had a significant impact on the carbon flow within the system, shifting the end product from methane and carbon dioxide to acetate and carbon dioxide. Interestingly, methane production quickly resumed, when sulfate was no longer present in the system. Despite the strong impact of sulfate addition on the carbon flow and the microbial community structure during thermophilic biogas production, short-term process disturbances caused by unexpected introduction of sulfate may be overcome due to the high resilience of the engaged microorganisms.
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Affiliation(s)
- Nina Lackner
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020, Innsbruck, Austria.
| | - Andreas O Wagner
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020, Innsbruck, Austria
| | - Paul Illmer
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020, Innsbruck, Austria
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Slorach PC, Jeswani HK, Cuéllar-Franca R, Azapagic A. Environmental sustainability of anaerobic digestion of household food waste. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 236:798-814. [PMID: 30776553 DOI: 10.1016/j.jenvman.2019.02.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 01/14/2019] [Accepted: 02/01/2019] [Indexed: 05/15/2023]
Abstract
Consumers are the leading producers of food waste (FW) in developed countries and the majority of household FW is still embedded in general waste where it is incinerated or landfilled. There is increasing awareness in the value of collecting FW as a separate waste stream for production of compost or recovery of energy through anaerobic digestion (AD). This study focuses on AD to evaluate the life cycle environmental sustainability of recovering energy and fertilisers from household FW in the UK. The analysis is carried out for two different functional units: i) treatment of 1 tonne of FW, which is compared to incineration and landfilling; and ii) generation of 1 MWh of electricity, which is compared to other electricity generation options. The former results in net negative greenhouse gas (GHG) emissions (-39 kg CO2-eq./t) and primary energy demand (-2 GJ/t) due to the displacement of grid electricity and mineral fertilisers. AD has lower impacts than both incineration and landfilling across 15 of the 19 impacts. However, the application of digestate to land and the release of ammonia and nitrates lead to higher marine eutrophication (ME), terrestrial acidification (TA) and particulate matter formation (PMF). For the second functional unit, AD electricity emits 203 kg CO2-eq./MWh, compared to 357 kg CO2-eq./MWh for the UK grid mix. Compared to renewables, such as wind and solar, AD electricity has lower energy demand, toxicity potentials and metal depletion. However, it has higher global warming potential, ME, TA and PMF. At the UK level, treating 4.9 Mt of kerbside FW collected annually could provide 0.37% of the national electricity demand and save 190,000 t CO2-eq./yr compared to the grid electricity. The digestate produced could displace 1% of industrial nitrogen fertilisers. Although small fractions of the national demands, they represent a valuable return from a largely unutilised waste stream and help towards implementation of a circular economy.
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Affiliation(s)
- Peter C Slorach
- Sustainable Industrials Systems, School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester, M13 9PL, UK
| | - Harish K Jeswani
- Sustainable Industrials Systems, School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester, M13 9PL, UK
| | - Rosa Cuéllar-Franca
- Sustainable Industrials Systems, School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester, M13 9PL, UK.
| | - Adisa Azapagic
- Sustainable Industrials Systems, School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester, M13 9PL, UK
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Wagner AO, Prem EM, Markt R, Kaufmann R, Illmer P. Formation of phenylacetic acid and phenylpropionic acid under different overload conditions during mesophilic and thermophilic anaerobic digestion. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:26. [PMID: 30787959 PMCID: PMC6368962 DOI: 10.1186/s13068-019-1370-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 02/03/2019] [Indexed: 05/08/2023]
Abstract
BACKGROUND Substrate spectra for anaerobic digestion have been broadened in the past decade, inter alia, due to the application of different pretreatment strategies and now include materials rich in lignocellulose, protein, and/or fat. The application of these substrates, however, also entails risks regarding the formation of undesired by-products, among which phenolic compounds are known to accumulate under unfavorable digestion conditions. METHODS Different states of overload were simulated in batch experiments while reviewing the generation of phenyl acids out of different lab-use substrates in order to evaluate the impact on biogas and methane production as well as some additional process performance parameters under defined laboratory conditions. Investigations were conducted under both mesophilic and thermophilic conditions. RESULTS It could be shown that the tested input materials led to the formation of phenyl acids in a substrate-dependent manner with the formation itself being less temperature driven. Once formed, the formation of phenyl acids turned out to be a reversible process. CONCLUSIONS Although a mandatory negative impact of phenyl acids per se on the anaerobic digestion process in general and the methanogenesis process in particular could not be proven, phenyl acids, however, seem to play an important role in the microbial response to overloaded biogas systems.
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Affiliation(s)
- Andreas Otto Wagner
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria
| | - Eva Maria Prem
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria
| | - Rudolf Markt
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria
| | - Rüdiger Kaufmann
- Department of Ecology, Universität Innsbruck, Sternwartestr. 15/Technikerstraße 25/5, 6020 Innsbruck, Austria
| | - Paul Illmer
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria
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Wagner AO, Janetschek J, Illmer P. Using Digestate Compost as a Substrate for Anaerobic Digestion. Chem Eng Technol 2018. [DOI: 10.1002/ceat.201700386] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Andreas Otto Wagner
- University of Innsbruck; Institute of Microbiology; Technikerstrasse 25d 6020 Innsbruck Austria
| | - Julian Janetschek
- University of Innsbruck; Institute of Microbiology; Technikerstrasse 25d 6020 Innsbruck Austria
| | - Paul Illmer
- University of Innsbruck; Institute of Microbiology; Technikerstrasse 25d 6020 Innsbruck Austria
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Bio-methane from an-aerobic digestion using activated carbon adsorption. Anaerobe 2017; 46:33-40. [DOI: 10.1016/j.anaerobe.2017.05.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 03/06/2017] [Accepted: 05/04/2017] [Indexed: 11/22/2022]
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Wagner AO, Markt R, Puempel T, Illmer P, Insam H, Ebner C. Sample preparation, preservation, and storage for volatile fatty acid quantification in biogas plants. Eng Life Sci 2016; 17:132-139. [PMID: 32624760 DOI: 10.1002/elsc.201600095] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 06/24/2016] [Accepted: 07/12/2016] [Indexed: 11/10/2022] Open
Abstract
Volatile fatty acids (VFA) represent short-chain fatty acids consisting of six or fewer carbon atoms that can be distilled at atmospheric pressure. In anaerobic digestion processes VFAs are of central importance for maintaining stable reactor performance and biogas production, are used as indicators for arising problems and are important process monitoring parameters. In the present study, sludge derived form a full-scale anaerobic digester of a wastewater treatment plant was spiked with formate, acetate, propionate, and butyrate in order to evaluate various commonly used techniques for VFA extraction, preservation, and storage. It was shown that VFA extraction after centrifugation warranted the highest recovery rates for spiked VFAs. Moreover, experiments clearly indicated the importance of a fast sample handling, including the necessity of immediate cooling of the samples. Chemical sample preservation within a narrow time frame or deep freezing emerged as an alternative to instant VFA extraction. Short-time storage of extracted VFA samples at + 4°C is an option for up to 7 days, for longer periods storage at -20°C was found to be applicable.
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Affiliation(s)
- Andreas O Wagner
- Institute of Microbiology University of Innsbruck Innsbruck Austria
| | - Rudolf Markt
- Institute of Microbiology University of Innsbruck Innsbruck Austria.,alpS GmbH Innsbruck Austria
| | - Thomas Puempel
- Institute of Microbiology University of Innsbruck Innsbruck Austria
| | - Paul Illmer
- Institute of Microbiology University of Innsbruck Innsbruck Austria
| | - Heribert Insam
- Institute of Microbiology University of Innsbruck Innsbruck Austria
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Mutschlechner M, Illmer P, Wagner AO. Biological pre-treatment: Enhancing biogas production using the highly cellulolytic fungus Trichoderma viride. WASTE MANAGEMENT (NEW YORK, N.Y.) 2015; 43:98-107. [PMID: 26013693 DOI: 10.1016/j.wasman.2015.05.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 05/07/2015] [Accepted: 05/11/2015] [Indexed: 06/04/2023]
Abstract
With regard to renewable sources of energy, bioconversion of lignocellulosic biomass has long been recognized as a desirable endeavor. However, the highly heterogeneous structure of lignocellulose restricts the exploitation of its promising potential in biogas plants. Hence, effective pre-treatment methods are decisive prerequisites to overcome these challenges in order to improve the utilization ratio of (ligno) cellulosic substrates during fermentation. In the present study, the application of Trichoderma viride in an aerobic upstream process prior to anaerobic digestion led up to a threefold increase in the yield of methane and total gas in a lab-scale investigation. Due to its highly efficient cellulolytic activities, T. viride seemed to be responsible for an improved nutrient availability that positively influenced the anaerobic microbiocenosis. Aerobic pre-treatment of organic matter with T. viride is therefore a promising solution to achieve higher methane yields and degradation performances without any additional energy demand, nor undesired by-product inhibition.
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Affiliation(s)
- Mira Mutschlechner
- Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, A-6020 Innsbruck, Austria.
| | - Paul Illmer
- Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, A-6020 Innsbruck, Austria
| | - Andreas Otto Wagner
- Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, A-6020 Innsbruck, Austria
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Insam H, Podmirseg SM, Wagner AO, Simunek J. No oxygen-still vigorous: 8th International Symposium on Anaerobic Microbiology (ISAM 8) Innsbruck, Austria. Anaerobe 2014; 29:1-2. [DOI: 10.1016/j.anaerobe.2014.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Wagner AO, Reitschuler C, Illmer P. Effect of different acetate:propionate ratios on the methanogenic community during thermophilic anaerobic digestion in batch experiments. Biochem Eng J 2014. [DOI: 10.1016/j.bej.2014.05.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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