Special Issue "Anaerobic Digestion Processes"

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Other Topics".

Deadline for manuscript submissions: 30 June 2020.

Special Issue Editors

Dr. Pietro Bartocci
E-Mail Website
Guest Editor
Department of Engineering, University of Perugia, Italy
Interests: bioenergy; LCA; power systems
Special Issues and Collections in MDPI journals
Prof. Qing Yang
E-Mail Website
Guest Editor
ICARE (China-EU Institute for Clean Air and Renewable Energy) & Harvard John A Poulson School of Engineering and Applied Sciences
Interests: LCA; environmental impact; energy
Prof. Francesco Fantozzi
E-Mail Website
Guest Editor
Department of Engineering, University of Perugia, Italy
Interests: thermal machines; power plants; bioenergy; energy from waste

Special Issue Information

Dear Colleagues,

Given the growing demand for green energy in developed and developing countries, biogas production from biomass and waste is a technology that can be used to produce renewable methane. This can be obtained as biogas or biomethane (through a successive upgrading step). Different substrates can be used in the anaerobic digestion process, such as energy crops, waste, and residual biomass, as well as food waste. Feedstock logistics, plant operation optimization, and biogas utilization in engines and turbines are key topics that must be carefully analyzed for the successful planning of biogas and biomethane projects. Process optimization should be based on the comprehension of biogas yields from different substrates, the analysis of pre-treatment processes of the raw materials, the optimization of pH in the reactor, the optimization of retention time, the optimization of volatile matter degradation efficiency, and process integration and heat integration to reduce waste heat production (e.g., from CHP units). Together with these conventional aspects, other innovative technologies have to be developed to purify biogas through fermentation, separation of CO2, hydrogenation of CO2, use of biochar in the digester, or for biogas purification.

This Special Issue on "Anaerobic Digestion Processes" aims to curate novel advances in biogas production and use, focusing both on modeling and experimental campaigns. Topics include, but are not limited to, the following:

  • Modeling of anaerobic digestion and biogas production;
  • Organic substrate characterization and pre-treatment;
  • Biogas purification and biomethane production and use;
  • Biogas combustion in engines and turbines.

Dr. Pietro Bartocci
Prof. Qing Yang
Prof. Francesco Fantozzi
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1200 CHF (Swiss Francs). Please note that for papers submitted after 31 December 2019 an APC of 1400 CHF applies. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • biogas
  • anaerobic digestion
  • biochar
  • biomethane
  • waste food
  • process integration
  • reactors
  • modeling
  • gas cleaning
  • emissions

Published Papers (2 papers)

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Research

Open AccessFeature PaperArticle
A Comparative Study of Biogas Reactor Fluid Rheology—Implications for Mixing Profile and Power Demand
Processes 2019, 7(10), 700; https://doi.org/10.3390/pr7100700 - 03 Oct 2019
Abstract
Anaerobic digestion (AD) is an established process for integrating waste management with renewable energy and nutrient recovery. Much of the research in this field focuses on the utilisation of new substrates, yet their effects on operational aspects such as fluid behaviour and power [...] Read more.
Anaerobic digestion (AD) is an established process for integrating waste management with renewable energy and nutrient recovery. Much of the research in this field focuses on the utilisation of new substrates, yet their effects on operational aspects such as fluid behaviour and power requirement for mixing are commonly overlooked, despite their importance for process optimisation. This study analysed rheological characteristics of samples from 21 laboratory-scale continuous stirred-tank biogas reactors (CSTBRs) digesting a range of substrates, in order to evaluate substrate effect on mixing efficiency and power demand through computational fluid dynamics (CFD). The results show that substrate and process parameters, such as solids content and organic loading, all have a significant effect on CSTBR fluid rheology. The correlation levels between rheological and process parameters were different across substrates, while no specific fluid behaviour patterns could be associated with substrate choice. Substrate should thus be considered an equally important rheology effector as process parameters. Additional substrate-related parameters should be identified to explain the differences in correlations between rheological and process parameters across substrate groups. The CFD modelling revealed that the rheology differences among the AD processes have significant implications for mixing efficiency and power demand of the CSTBRs, highlighting the importance of considering the substrate-induced effects on CSTBR rheology before including a new substrate. Full article
(This article belongs to the Special Issue Anaerobic Digestion Processes)
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Open AccessFeature PaperArticle
Biogas Generation through Anaerobic Digestion of Compost Leachate in Semi-Continuous Completely Stirred Tank Reactors
Processes 2019, 7(9), 635; https://doi.org/10.3390/pr7090635 - 18 Sep 2019
Abstract
The composting process of organic fraction of municipal solid waste, besides to the residual compost, generates a wastewater that is characterized by a high organic load. The application of anaerobic processes represents an advantageous solution for the treatment and valorization of this type [...] Read more.
The composting process of organic fraction of municipal solid waste, besides to the residual compost, generates a wastewater that is characterized by a high organic load. The application of anaerobic processes represents an advantageous solution for the treatment and valorization of this type of wastewater. Nevertheless, few works have been focused on the anaerobic digestion of compost leachate. To overcome this dearth, in the present paper an extensive experimental investigation was carried out to develop and analyse the anaerobic treatment of young leachate in completely stirred tank reactors (CSTR). Initially, it was defined a suitable leachate pretreatment to correct its acidic characteristics that is potentially able to inhibit methanogenic biomass activity. The pretreated leachate was fed to the digester over the start-up phase that was completed in about 40 days. During the operational period, the organic load rate (OLR) changed between 4.25 kgCOD/m3d and 38.5 kgCOD/m3d. The chemical oxygen demand (COD) abatement was higher than 90% for OLR values up to 14.5 kgCOD/m3d and around to 80% for applied loads equal to 24.5 kgCOD/m3d. At this OLR, it was reached the maximum daily biogas production of about 9.3 Lbiogas/(Lreactord). The CH4 fraction was between 70%–78% and the methane production yield in the range 0.34–0.38 LCH4/gCODremoved. The deterioration of biogas production started for OLR values that were over the threshold of 24.5 kgCOD/m3d when a volatile fatty acids (VFA) accumulation occurred and the pH dropped below 6.5. The maximum ratio between VFA and alkalinity (ALK) tolerable in the CSTR was identified to be 0.5 gCH3COOH/gCaCO3. Through an economic analysis, it was proven that the digestion of compost leachate could ensure significant economic profits. Furthermore, the produced digestate had characteristics that were compatible for agricultural applications. Full article
(This article belongs to the Special Issue Anaerobic Digestion Processes)
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