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Anaerobic Digestion for Bioenergy and Biochemicals Production

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A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Environmental and Green Processes".

Deadline for manuscript submissions: closed (31 March 2021) | Viewed by 17341

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Special Issue Editors

Dr. Davide Dionisi

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Guest Editor

School of Engineering, Fraser Noble Building Kings College, University of Aberdeen, Aberdeen AB24 3UE, UK
Interests: biological wastewater treatment; innovative processes for chemicals (ethanol, organic acids, hydrogen, methane) and energy production from lignocellulosic biomass and organic waste; aerobic and anaerobic processes; biodegradation of xenobiotics
Special Issues, Collections and Topics in MDPI journals

Dr. Yue Zhang

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Guest Editor

Faculty of Engineering and Physical Sciences, University of Southampton, Southampton Boldrewood Innovation Campus, Southampton SO16 7QF, UK
Interests: anaerobic digestion; bioenergy production; organic waste management; heavy metal removal; water and wastewater treatment
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Anaerobic digestion (AD) of biomass and organic waste has an important potential for the generation of renewable and sustainable energy. Methane, the desired product from AD, can be used for electricity, heat, and as transport fuel. Although AD has been in commercial use for many decades, most of its potential in energy generation is yet to be delivered.

In recent years, research has also examined the use of AD in the production of chemicals other than methane, e.g., organic acids and hydrogen. These chemicals, used for many purposes in the chemical and food industry, are currently mainly produced from fossil fuels. Their production from biomass and organic waste via AD could represent a big step forward for a sustainable chemical industry which uses renewable feedstocks.

Research, innovation, and process development are required for AD to deliver its full potential for the production of bioenergy and biochemicals. An increase in conversion yields, process productivity, and product concentration along with a reduction in process costs are among the factors which can advance AD technology. This Special Issue seeks high-quality work which contributes to advancing AD and getting it closer to delivering its full potential. Topics include, but are not limited to:

Innovative AD processes;
Improvements in AD technology and processes;
Pre-treatments;
New sustainable feedstocks;
Use of AD for organic acids and hydrogen production;
Microbiology of AD;
Economics and life cycle assessment of AD

Dr. Davide Dionisi
Dr. Yue Zhang
Guest Editors

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Keywords

anaerobic digestion
anaerobic fermentation
biomethane
organic acids
hydrogen
organic waste
biomass

Published Papers (5 papers)

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Research

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13 pages, 2625 KiB

Open AccessFeature PaperArticle

Anaerobic Degradation of Individual Components from 5-Hydroxymethylfurfural Process-Wastewater in Continuously Operated Fixed Bed Reactors

by Muhammad Tahir Khan, Johannes Krümpel, Dominik Wüst and Andreas Lemmer

Processes 2021, 9(4), 677; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9040677 - 13 Apr 2021

Cited by 5 | Viewed by 2715

Abstract

Production of bio-based materials in biorefineries is coupled with the generation of organic-rich process-wastewater that requires further management. Anaerobic technologies can be employed as a tool for the rectification of such hazardous by-products. Therefore, 5-hydroxymethylfurfural process-wastewater and its components were investigated for their biodegradability in a continuous anaerobic process. The test components included 5-hydroxymethylfurfural, furfural, levulinic acid, and the full process-wastewater. Each component was injected individually into a continuously operating anaerobic filter at a concentration of 0.5 gCOD. On the basis of large discrepancies within the replicates for each component, we classified their degradation into the categories of “delayed”, “retarded”, and “inhibitory”. Inhibitory represented the replicates for all the test components that hampered the process. For the retarded degradation, their mean methane yield per 0.5 gCOD was between 21.31 ± 13.04 mL and 28.98 ± 25.38 mL. Delayed digestion was considered adequate for further assessments in which the order of conversion to methane according to specific methane yield for each component from highest to lowest was as follows: levulinic acid > furfural > 5-hydroxymethylfurfural > process-wastewater. Disparities and inconsistencies in the degradation of process-wastewater and its components can compromise process stability as a whole. Hence, the provision of energy with such feedstock is questionable. Full article

(This article belongs to the Special Issue Anaerobic Digestion for Bioenergy and Biochemicals Production)

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10 pages, 1075 KiB

Open AccessArticle

The Effects of Hot Water and Ultrasonication Pretreatment of Microalgae (Nannochloropsis oculata) on Biogas Production in Anaerobic Co-Digestion with Cow Manure

by Muhammad Saleem, Muhammad Usman Hanif, Ali Bahadar, Hamid Iqbal, Sergio C. Capareda and Adeel Waqas

Processes 2020, 8(12), 1558; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8121558 - 27 Nov 2020

Cited by 11 | Viewed by 2012

Abstract

Anaerobic co-digestion provides a promising solution for converting inexpensive carbon from wastes to biogenic methane. We used microalgae (Nannochloropsis oculata) with cow manure and sludge to produce a better quantity and quality of biogas. To further improve the gas production, microalgae were pretreated with ultrasonication, hot water, and a combination of both. Interestingly, the results showed that the pretreatment of microalgae decreased biogas production by 5 to 30%. The no-pretreatment runs produced a maximum of 118 L of biogas. The relative content of biogenic methane was higher in the pretreated feedstock (48 to 52%) in comparison with the no-pretreatment runs (44%). The conversion of volatile suspended solids present in the feedstock to total biogenic methane production was highest in hot-water-treated runs. The carbon content in the gas produced by the pretreated microalgae peaked (38%) in the middle of the experiment (i.e., at 45 days), whereas for no-pretreatment runs, the content remained constant from the start to the middle and declined (from 36 to 34%) at the end of the experiment (i.e., at 90 days). We also report the chemical structure of microalgae with and without pretreatments. Full article

(This article belongs to the Special Issue Anaerobic Digestion for Bioenergy and Biochemicals Production)

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18 pages, 2636 KiB

Open AccessArticle

Adjusting Organic Load as a Strategy to Direct Single-Stage Food Waste Fermentation from Anaerobic Digestion to Chain Elongation

by Vicky De Groof, Marta Coma, Tom C. Arnot, David J. Leak and Ana B. Lanham

Processes 2020, 8(11), 1487; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8111487 - 18 Nov 2020

Cited by 16 | Viewed by 3826

Abstract

Production of medium chain carboxylic acids (MCCA) as renewable feedstock bio-chemicals, from food waste (FW), requires complicated reactor configurations and supplementation of chemicals to achieve product selectivity. This study evaluated the manipulation of organic loading rate in an un-supplemented, single stage stirred tank reactor to steer an anaerobic digestion (AD) microbiome towards acidogenic fermentation (AF), and thence to chain elongation. Increasing substrate availability by switching to a FW feedstock with a higher COD stimulated chain elongation. The MCCA species n-caproic (10.1 ± 1.7 g L⁻¹) and n-caprylic (2.9 ± 0.8 g L⁻¹) acid were produced at concentrations comparable to more complex reactor set-ups. As a result, of the adjusted operating strategy, a more specialised microbiome developed containing several MCCA-producing bacteria, lactic acid-producing Olsenella spp. and hydrogenotrophic methanogens. By contrast, in an AD reactor that was operated in parallel to produce biogas, the retention times had to be doubled when fed with the high-COD FW to maintain biogas production. The AD microbiome comprised a diverse mixture of hydrolytic and acidogenic bacteria, and acetoclastic methanogens. The results suggest that manipulation of organic loading rate and food-to-microorganism ratio may be used as an operating strategy to direct an AD microbiome towards AF, and to stimulate chain elongation in FW fermentation, using a simple, un-supplemented stirred tank set-up. This outcome provides the opportunity to repurpose existing AD assets operating on food waste for biogas production, to produce potentially higher value MCCA products, via simple manipulation of the feeding strategy. Full article

(This article belongs to the Special Issue Anaerobic Digestion for Bioenergy and Biochemicals Production)

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29 pages, 9089 KiB

Open AccessFeature PaperArticle

Significance of Pretreatment in Enhancing the Performance of Dry Anaerobic Digestion of Food Waste: An Insight on Full Scale Implementation Strategy with Theoretical Analogy

by Vijayalakshmi Arelli, Sudharshan Juntupally, Sameena Begum and Gangagni Rao Anupoju

Processes 2020, 8(9), 1018; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8091018 - 20 Aug 2020

Cited by 11 | Viewed by 3925

Abstract

The aim of this study was to treat food waste containing 25% total solids (TS) through dry anaerobic digestion (dry AD) process at various pressures (0.5 to 2.5 kg/cm²) and different time duration (20 to 100 min) to understand the impact of pretreatment in enhancing the methane generation potential along with insights on scale up. The findings revealed that vs. reduction and methane yield of 60% and 0.25 L CH₄/(g VS_added) can be achieved with pretreated food waste at two kilograms per square centimeter, while pretreatment of food waste at 2 kg/cm² for 100 min enhanced the vs. reduction from 60% to 85% and methane yield from 0.25 to 0.368 L CH₄/(g VS_added). However, the net energy indicated that 40 min of pre -treatment at two kilograms per square centimeter can be a suitable option as methane yield and vs. reduction of 0.272 L CH₄/(g VS_added) and 70%, respectively was achieved. The vs. reduction and the methane yield of 45% and 0.14 L CH₄/(g VS_added), respectively was obtained from untreated food waste which illustrated that pretreatment had significantly impacted on the enhancement of methane generation and organic matter removal which can make the dry AD process more attractive and feasible at commercial scale. Full article

(This article belongs to the Special Issue Anaerobic Digestion for Bioenergy and Biochemicals Production)

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Review

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17 pages, 3071 KiB

Open AccessFeature PaperReview

Product Concentration, Yield and Productivity in Anaerobic Digestion to Produce Short Chain Organic Acids: A Critical Analysis of Literature Data

by Serena Simonetti, Agus Saptoro, Claudia Fernández Martín and Davide Dionisi

Processes 2020, 8(12), 1538; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8121538 - 25 Nov 2020

Cited by 7 | Viewed by 3957

Abstract

In order to make anaerobic digestion-based processes for short chain organic acid (SCOA) production attractive, the key performance variables, i.e., concentration, yield, and productivity of the produced SCOAs need to be maximised. This study analysed recent literature, looking for the effect of process operating parameters (feed concentration, pH, temperature, and residence time) on the performance variables. Data from 551 experiments were analysed. Mean values of the SCOA concentration, yield, and productivity were 10 g l⁻¹, 32% (chemical oxygen demand (COD) COD⁻¹), and 1.9 g l⁻¹ day⁻¹, respectively. Feed concentration and residence time had the most important effect. Higher feed concentration corresponded to higher product concentration and productivity, but to lower yield. The mean feed concentration was 109 gCOD l⁻¹ and 19 gCOD l⁻¹ in the experiments with the highest product concentrations and in the experiments with the highest yields, respectively. Shorter residence times corresponded to higher productivity. The mean HRT (hydraulic residence time) in the experiments with the highest productivities was 2.5 days. Sequencing batch reactors gave higher values of the performance variables (mean values 29 g l⁻¹, 41% COD COD⁻¹, and 12 g l⁻¹ day⁻¹ for product concentration, yield, and productivity, respectively) than processes without phase separation. Full article

(This article belongs to the Special Issue Anaerobic Digestion for Bioenergy and Biochemicals Production)

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