Recirculation of solid digestate to enhance energy efficiency of biogas plants: Strategies, conditions and impacts

Brémond, Ulysse; Bertrandias, Aude; Buyer, Raphaëlle de; Latrille, Éric; Jimenez, Julie; Escudié, Renaud; Steyer, Jean‐Philippe; Bernet, Nicolas; Carrère, Hélène

doi:10.1016/j.enconman.2020.113759

Cited by 17 publications

(11 citation statements)

References 38 publications

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“…Solid digestate used in this study came from an agricultural biogas plant treating sequential crops, cattle manure, beet pulp, cereal dust and whey. More information on this plant can be found in Brémond et al, under the name Biogas Plant A [4].…”

Section: Initial Environmentsmentioning

confidence: 99%

“…SD was complexified via a chemical method described in Jimenez et al, (2015) [13]. Composition of the SD used in this study was characterized previously via the same methodology [4]. Raw SD had the following composition in percentage of the total COD: 5% ± 0.1 soluble sugars and proteins, 10.8% ± 0.1 remaining proteins and sugars, some humic substances and lipids, 39.8% ± 0.1 hemicellulose and cellulose and 44.3% ± 0.3 lignin-like compounds.…”

Section: Preparation Of the Carbon Source And Solutionsmentioning

confidence: 99%

“…At the end of this period, biomethane potential (BMP) tests were launched directly using the flasks according to the protocol described in Bremond et al, (2021) [4]. A control made of untreated sterilized SD was added to the BMP run.…”

Section: Addition Of a Consortia Solution To Enhance Short-term Aerob...mentioning

confidence: 99%

“…Therefore, carbon losses due to respiration were taken into account despite the fact that they were not measured during the post-treatment. Finally, chemical oxygen demand (COD) measurements were performed on liquid consortia to evaluate additional methane that could be produced during the BMP test due to remaining organic matter in the liquid [4]. Figure S3 in the Supplemental File describes in detail this last step.…”

Section: Addition Of a Consortia Solution To Enhance Short-term Aerob...mentioning

confidence: 99%

“…By doing so, the refractory and complex solid organic matter that composed the solid digestate can remain longer under anaerobic conditions, allowing further conversion to biogas. Without any post-treatment and by recirculation, the methane production of a continuous stirred-tank reactor biogas plant can be increased between 0.6 and 6.3% [4]. In the same study, short-term aerobic post-treatment of the solid digestate (SD) using endogenous microorganisms was not successful and led to lower methane potentials due to carbon losses via respiration.…”

Section: Introductionmentioning

confidence: 96%

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Screening and Application of Ligninolytic Microbial Consortia to Enhance Aerobic Degradation of Solid Digestate

et al. 2022

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Recirculation of solid digestate through digesters has been demonstrated to be a potential simple strategy to increase continuous stirred-tank reactor biogas plant efficiency. This study extended this earlier work and investigated solid digestate post-treatment using liquid isolated ligninolytic aerobic consortia in order to increase methane recovery during the recirculation. Based on sampling in several natural environments, an enrichment and selection method was implemented using a Lab-scale Automated and Multiplexed (an)Aerobic Chemostat system to generate ligninolytic aerobic consortia. Then, obtained consortia were further cultivated under liquid form in bottles. Chitinophagia bacteria and Sordariomycetes fungi were the two dominant classes of microorganisms enriched through these steps. Finally, these consortia where mixed with the solid digestate before a short-term aerobic post-treatment. However, consortia addition did not increase the efficiency of aerobic post-treatment of solid digestate and lower methane yields were obtained in comparison to the untreated control. The main reason identified is the respiration of easily degradable fractions (e.g., sugars, proteins, amorphous cellulose) by the selected consortia. Thus, this paper highlights the difficulties of constraining microbial consortia to sole ligninolytic activities on complex feedstock, such as solid digestate, that does not only contain lignocellulosic structures.

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Section: Initial Environmentsmentioning

confidence: 99%