Anaerobic Digestion Process: Converting Waste to Energy

A special issue of Methane (ISSN 2674-0389).

Deadline for manuscript submissions: 31 March 2024 | Viewed by 12066

Special Issue Editors

Department of Biological and Chemical Engineering, Aarhus University, 8000 Aarhus, Denmark
Interests: Anaerobic digestion; pretreatment technology; life cycle analysis; in situ biomethanation; Power-to-X
Department of Civil Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
Interests: Integrated solid waste management; sustainable engineering; circular economy; life cycle analysis; environmental nanotechnology

Special Issue Information

Dear Colleagues,

Anaerobic digestion (AD) plays an important role in the conversion of organic waste where biogas has been produced as an end product of the digestion process. Different organic wastes, including animal waste, municipal waste, plant biomass such as agro-residue, weed, fruit and vegetable wastes, have been used as feedstock for biogas production. AD is one of the most widely used waste-to-energy techniques. There are thousands of large-scale and millions of small-scale AD systems currently in operation around the globe. AD technology is by far the single most important technology for treating organic waste and for providing clean renewable energy. AD technology has several benefits, such as generating renewable energy, remediating waste, and curtailing greenhouse gas emissions to improve health/hygiene and the overall socio-economic status of a given nation. Our dependence on rapidly depleting non-renewable energy sources has several irreparable consequences, including damage to economic development, national security, the local and global environment, climate change, and others. AD/biogas technology can provide sustainable, affordable, and environmentally friendly energy resources, utilizing biochemicals from renewable bioresources (e.g., energy crops, agri- and forest residues, organic wastes, high-strength wastewaters, etc.). In recent years, significant advances have been made in AD technology with an emphasis on the recovery of energy. Thus, this Special Issue, “Anaerobic Digestion Process: Converting Waste to Energy”, has been conceptualized to highlight some of these advances. We are especially interested in state-of-the-art critical reviews in the following areas:

  • Resource recovery from organic waste;
  • Pretreatment technologies;
  • Anaerobic digestion and climate change mitigation;
  • Microbial community analysis in AD systems;
  • Anaerobic digestion process control, bioenergetics and modelling;
  • Biogas upgrading and utilization;
  • Anaerobic digestion biorefinery;
  • Digestate utilization;
  • Life cycle and techno-economic analysis;
  • AD technology and policy.

Dr. Sagarika Panigrahi
Dr. Brajesh Kumar Dubey
Guest Editors

Manuscript Submission Information

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Keywords

  • Resource recovery from organic waste
  • Pretreatment technologies
  • Anaerobic digestion and climate change mitigation
  • Microbial community analysis in AD systems
  • Anaerobic digestion process control, bioenergetics and modelling
  • Biogas upgrading and utilization
  • Anaerobic digestion biorefinery
  • Digestate utilization
  • Life cycle and techno-economic analysis
  • AD technology and policy.

Published Papers (7 papers)

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Research

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12 pages, 1924 KiB  
Article
Effect of Particle Size on the Biomethanation Kinetics of Mechanically Pretreated Sargassum spp. Biomass
by Rosy Paletta, Rossella Girimonte, Yessica A. Castro, Jose Atilio De Frias and Vincenza Calabrò
Methane 2024, 3(1), 160-171; https://doi.org/10.3390/methane3010010 - 04 Mar 2024
Viewed by 563
Abstract
The collection and use of Sargassum spp. as feedstock for the production of valuable products such as biomethane by anaerobic digestion (AD) would mitigate the negative impact of the blooms and the costs related to waste management in the Dominican Republic. In this [...] Read more.
The collection and use of Sargassum spp. as feedstock for the production of valuable products such as biomethane by anaerobic digestion (AD) would mitigate the negative impact of the blooms and the costs related to waste management in the Dominican Republic. In this work, the effect of the particle size of pelagic Sargassum spp. biomass, as a result of mechanical pretreatments, on the biomethanation was determined. The granulometric analysis of the mechanically pre-treated biomass was carried out using a Mastersize2000. The Biochemical Methane Potential (BMP) of the samples was determined using an Automatic Potential System Test II (AMPTS® II). The kinetic parameters of the reaction were scientifically evaluated by using First order kinetic Model and modified Gompertz Model. The granulometric analysis showed a monomodal distribution on crushed biomass (505 µm) and a bimodal distribution on the milling sample (107 µm). The bimodal biomass means the biomass is characterized by the presence of fine and large particles. We observed that BMP increased by 78.85% when particles were reduced from 50,000 µm to 505 µm and by 73.61% when particles were reduced from 50,000 µm to 107 µm. A low methane yield from the milling biomass (107 µm) compared to the crushed biomass (505 µm) could be related to the excessive reduction of particle size. The fine particles are subject to the formation of aggregates and consequently, the contact area between the algae cells and the microorganisms that operate the anaerobic digestion process decreases. Full article
(This article belongs to the Special Issue Anaerobic Digestion Process: Converting Waste to Energy)
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21 pages, 3581 KiB  
Article
The Trade-Off between Enteric and Manure Methane Emissions and Their Bacterial Ecology in Lactating Cows Fed Diets Varying in Forage-to-Concentrate Ratio and Rapeseed Oil
by Babak Darabighane, Ilma Tapio, Saija Rasi, Ari-Matti Seppänen, Lucia Blasco, Seppo Ahvenjärvi and Ali R. Bayat
Methane 2024, 3(1), 12-32; https://doi.org/10.3390/methane3010002 - 09 Jan 2024
Cited by 1 | Viewed by 574
Abstract
An experiment was conducted to examine how dietary interventions reducing enteric methane (CH4) emissions influence manure CH4 emissions in biogas production (as biochemical methane potential (BMP)) or under static conditions mimicking natural manure storage conditions. Experimental treatments consisted of a [...] Read more.
An experiment was conducted to examine how dietary interventions reducing enteric methane (CH4) emissions influence manure CH4 emissions in biogas production (as biochemical methane potential (BMP)) or under static conditions mimicking natural manure storage conditions. Experimental treatments consisted of a factorial arrangement of high (HF: 0.65) or low (LF: 0.35) levels of forage and 0 or 50 g of rapeseed oil per kg of diet dry matter. Oil supplementation reduced daily enteric CH4 emissions, especially in the HF diet, by 20%. Greater dietary concentrate proportion reduced CH4 yield and intensity (6 and 12%, respectively) and decreased pH, increased total volatile fatty acids, and molar proportions of butyrate and valerate in feces incubated under static conditions. Oil supplementation increased daily BMP and BMP calculated per unit of organic matter (OM) (17 and 15%, respectively). Increased dietary concentrate had no impact on daily BMP and BMP per unit of OM, whereas it reduced daily CH4 production by 89% and CH4 per unit of OM by 91% under static conditions. Dietary oil supplementation tended to decrease fecal CH4 production per unit of digestible OM (23%) under static conditions. Diets had no impact on the alpha diversity of ruminal prokaryotes. After incubation, the fecal prokaryote community was significantly less diverse. Diets had no effect on alpha diversity in the BMP experiment, but static trial fecal samples originating from the HF diet showed significantly lower diversity compared with the LF diet. Overall, the tested dietary interventions reduced enteric CH4 emissions and reduced or tended to reduce manure CH4 emissions under static conditions, indicating a lack of trade-off between enteric and manure CH4 emissions. The potential for increasing CH4 yields in biogas industries due to dietary interventions could lead to a sustainable synergy between farms and industry. Full article
(This article belongs to the Special Issue Anaerobic Digestion Process: Converting Waste to Energy)
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15 pages, 2619 KiB  
Article
The Effects of Using Evogen Biogas Additive on the Microbiome and Performance of Full-Scale Biogas Plant
by Themistoklis Sfetsas, Manthos Panou, Afroditi G. Chioti, Nikoleta Prokopidou and Ioanna Dalla
Methane 2023, 2(3), 329-343; https://doi.org/10.3390/methane2030022 - 03 Sep 2023
Cited by 1 | Viewed by 922
Abstract
Biogas production from organic waste is a promising renewable energy source, but achieving optimal production and digester stability can be challenging. This study investigated the impact of the Evogen microbial additive on biogas production and digester status in two biogas plants (BG01 and [...] Read more.
Biogas production from organic waste is a promising renewable energy source, but achieving optimal production and digester stability can be challenging. This study investigated the impact of the Evogen microbial additive on biogas production and digester status in two biogas plants (BG01 and BG02). Microbial abundance and physicochemical parameters were analyzed to assess the effects. The results show distinct microbial community shifts in Evogen-treated digesters, with increased abundance of methanogenic archaea and hydrolytic bacteria, indicating improved anaerobic digestion. Evogen supplementation positively influenced digester performance, as evidenced by higher alkalinity buffer capacity (FOS/TAC ratios), indicating enhanced acidification and methanogenesis, along with reductions in total solids and volatile solids, demonstrating improved organic matter degradation. Evogen-treated digesters exhibited significantly higher biogas production and improved process stability, as indicated by volatile fatty acids (VFAs) profiling. The dominance of Firmicutes, Synergistetes, Proteolytic Bacteroidetes and Actinobacteria highlighted their roles in substrate degradation and VFA production. The findings contribute to optimizing biogas production systems and understanding complex microbial interactions within anaerobic digesters. The addition of Evogen influenced microbial community composition and dynamics, potentially altering substrate utilization, metabolic interactions and overall community structure. Full article
(This article belongs to the Special Issue Anaerobic Digestion Process: Converting Waste to Energy)
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14 pages, 2789 KiB  
Article
Anaerobic Digestion Remediation in Three Full-Scale Biogas Plants through Supplement Additions
by Eleni Anna Economou, Georgia Dimitropoulou, Nikoleta Prokopidou, Ioanna Dalla and Themistoklis Sfetsas
Methane 2023, 2(3), 265-278; https://doi.org/10.3390/methane2030018 - 18 Jul 2023
Cited by 1 | Viewed by 1456
Abstract
Additives can improve the efficiency of anaerobic digestion by increasing biogas production, reducing air pollution, and preventing ammonia inhibition. Biological or chemical supplementation can also improve the economic efficiency of anaerobic digestion. However, the effects of specific additives on biogas production can vary, [...] Read more.
Additives can improve the efficiency of anaerobic digestion by increasing biogas production, reducing air pollution, and preventing ammonia inhibition. Biological or chemical supplementation can also improve the economic efficiency of anaerobic digestion. However, the effects of specific additives on biogas production can vary, depending on the type of supplement used. This research utilizes the additives on an industrial scale and monitors the optimization of the anaerobic digestion operating parameters after their addition. The various AD additives were examined in a sufficient cycle of operation for three biogas plants located in northern Greece. In this manner, the effectiveness was investigated in multiple initial feeds and unstable operating situations caused by the seasonality of specific feedstocks. The existing operation state in the three biogas plants was recorded before and after adding the supplements. The addition of zeolite contributed to the reduction in the total ammoniacal nitrogen values in BG01 and BG03 plants. 8.4 tn of zeolite were added to the BG01 and BG03 plants over a period of two months. Low levels of trace element concentrations were observed in the BG02 plant; this issue was addressed by adding 5 kg of a trace element mixture every week over a period of 60 days. Introducing additives proved to be a stabilization factor in AD performance and an inhibition mediator. Full article
(This article belongs to the Special Issue Anaerobic Digestion Process: Converting Waste to Energy)
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16 pages, 1912 KiB  
Article
Techno-Economic Assessment of On-Site Production of Biomethane, Bioenergy, and Fertilizer from Small-Scale Anaerobic Digestion of Jabuticaba By-Product
by William Gustavo Sganzerla, Rafael Gabriel da Rosa, Tiago Linhares Cruz Tabosa Barroso, Luiz Eduardo Nochi Castro and Tânia Forster-Carneiro
Methane 2023, 2(2), 113-128; https://doi.org/10.3390/methane2020009 - 28 Mar 2023
Cited by 2 | Viewed by 1814
Abstract
Bioenergy recovery from biomass by-products is a promising approach for the circular bioeconomy transition. However, the management of agri-food by-products in stand-alone treatment facilities is a challenge for the low-capacity food processing industry. In this study, the techno-economic assessment of a small-scale anaerobic [...] Read more.
Bioenergy recovery from biomass by-products is a promising approach for the circular bioeconomy transition. However, the management of agri-food by-products in stand-alone treatment facilities is a challenge for the low-capacity food processing industry. In this study, the techno-economic assessment of a small-scale anaerobic digestion process was evaluated for the management of jabuticaba by-product and the production of biomethane, electricity, heat, and fertilizer. The process was simulated for a treatment capacity of 782.2 m3 y−1 jabuticaba peel, considering the experimental methane production of 42.31 L CH4 kg−1 TVS. The results of the scaled-up simulated process demonstrated the production of biomethane (13,960.17 m3 y−1), electricity (61.76 MWh y−1), heat (197.62 GJ y−1), and fertilizer (211.47 t y−1). Economic analysis revealed that the process for biomethane recovery from biogas is not profitable, with a net margin of −19.58% and an internal rate of return of −1.77%. However, biogas application in a heat and power unit can improve project feasibility, with a net margin of 33.03%, an internal rate of return of 13.14%, and a payback of 5.03 years. In conclusion, the application of small-scale anaerobic digestion can prevent the wrongful open-air disposal of jabuticaba by-products, with the generation of renewable energy and biofertilizer supporting the green economy toward the transition to a circular economy. Full article
(This article belongs to the Special Issue Anaerobic Digestion Process: Converting Waste to Energy)
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Review

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20 pages, 1730 KiB  
Review
A Review on Dry Anaerobic Digestion: Existing Technologies, Performance Factors, Challenges, and Recommendations
by Umer Hayyat, Muhammad Usman Khan, Muhammad Sultan, Umair Zahid, Showkat Ahmad Bhat and Mohd Muzamil
Methane 2024, 3(1), 33-52; https://doi.org/10.3390/methane3010003 - 15 Jan 2024
Viewed by 993
Abstract
With the increase in the growing rate of municipal solid waste throughout the world and due to the high moisture and organic components of the organic fraction of municipal solid waste, dry anaerobic digestion has become the future direction to cope with this [...] Read more.
With the increase in the growing rate of municipal solid waste throughout the world and due to the high moisture and organic components of the organic fraction of municipal solid waste, dry anaerobic digestion has become the future direction to cope with this waste while reducing the impact on the environment, including climate change. Dry anaerobic digestion has become a promising technology that converts the organic fraction of municipal solid waste into combustible biogases, which can be used as an alternative energy source. However, the technology faces several challenges that must be addressed to enhance its performance and adoption. This paper provides a comprehensive analysis of the current technologies used for dry anaerobic digestion in OFMSW and delves into the various factors that influence the performance of these technologies. This review paper also identifies and discusses the challenges faced in optimizing and scaling up these technologies, such as feedstock pretreatment requirements, characteristics of inoculum, and other crucial parameters. Full article
(This article belongs to the Special Issue Anaerobic Digestion Process: Converting Waste to Energy)
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26 pages, 1003 KiB  
Review
Biogas and Syngas Production from Sewage Sludge: A Sustainable Source of Energy Generation
by Nwabunwanne Lilian Enebe, Chinyere Blessing Chigor, KeChrist Obileke, Mohammed Shariff Lawal and Matthew Chekwube Enebe
Methane 2023, 2(2), 192-217; https://doi.org/10.3390/methane2020014 - 29 Apr 2023
Cited by 2 | Viewed by 5060
Abstract
Sewage sludge to energy conversion is a sustainable waste management technique and a means of militating against the environmental concerns associated with its disposal. Amongst the various conversion technologies, anaerobic digestion and gasification have been identified as the two most promising. Therefore, this [...] Read more.
Sewage sludge to energy conversion is a sustainable waste management technique and a means of militating against the environmental concerns associated with its disposal. Amongst the various conversion technologies, anaerobic digestion and gasification have been identified as the two most promising. Therefore, this study is focused on a detailed evaluation of the anaerobic digestion and gasification of sewage sludge for energy production. Moreover, the key challenges hindering both technologies are discussed, as well as the practical measures for addressing them. The applicable pretreatment measures for efficient transformation into valuable energy vectors were further evaluated. Specifically, the study evaluated various properties of sewage sludge in relation to gasification and anaerobic digestion. The findings showed that a high ash content in sewage sludge results in sintering and agglomeration, while a high moisture content promotes tar formation, which has been identified as one of the key limitations of sewage sludge gasification. More importantly, the application of pretreatment has been shown to have some beneficial features in promoting organic matter decomposition/degradation, thereby enhancing biogas as well as syngas production. However, this has additional energy requirements and operational costs, particularly for thermal and mechanical methods. Full article
(This article belongs to the Special Issue Anaerobic Digestion Process: Converting Waste to Energy)
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