Change search
Link to record
Permanent link

Direct link
Benavente, VerónicaORCID iD iconorcid.org/0000-0003-3252-467X
Alternative names
Publications (2 of 2) Show all publications
Benavente, V., Pérez, C. & Jansson, S. (2024). Co-hydrothermal carbonization of microalgae and digested sewage sludge: Assessing the impact of mixing ratios on the composition of primary and secondary char. Waste Management, 174, 429-438
Open this publication in new window or tab >>Co-hydrothermal carbonization of microalgae and digested sewage sludge: Assessing the impact of mixing ratios on the composition of primary and secondary char
2024 (English)In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 174, p. 429-438Article in journal (Refereed) Published
Abstract [en]

The role of microalgae cultivation in wastewater treatment and reclamation has been studied extensively, as has the potential utility of the resulting algal biomass. Most methods for processing such biomass generate solid residues that must be properly managed to comply with current sustainable resource utilization requirements. Hydrothermal carbonization (HTC) can be used to process both individual wet feedstocks and mixed feedstocks (i.e., co-HTC). Here, we investigate co-HTC using microalgae and digested sewage sludge as feedstocks. The objectives were to (i) study the material’s partitioning into solid and liquid products, and (ii) characterize the products’ physicochemical properties. Co-HTC experiments were conducted at 180–250°C using mixed microalgae/sewage sludge feedstocks with the proportion of sewage sludge ranging from 0 to 100 %. Analyses of the hydrochar composition and the formation and composition of secondary char revealed that the content of carbonized material in the product decreased as the proportion of sewage sludge in the feedstock increased under fixed carbonization conditions. The properties of the hydrochars and the partitioning of material between the liquid phase and the hydrochar correlated linearly with the proportion of microalgae in mixed feedstocks, indicating that adding sewage sludge to microalgae had weak or non-existent synergistic effects on co-HTC outcomes. However, the proportion of sewage sludge in the feedstock did affect the secondary char. For example, adding sewage sludge reduced the abundance of carboxylic acids and ketones as well as the concentrations of higher molecular weight cholesterols. Such changes may alter the viable applications of the hydrochar. 

Place, publisher, year, edition, pages
Elsevier Ltd, 2024
Keywords
Algae; Carbonization; Feedstocks; Ketones; Microorganisms; Physicochemical properties; Sewage sludge; Wastewater treatment; Chemical compositions; Co-hydrothermal carbonization; Digested sewage sludge; Hydrochar; Hydrothermal carbonization; Micro-algae; Microalgae cultivation; Mixed feedstock; Mixing ratios; Wastewater treatment by-product; Thermogravimetric analysis
National Category
Microbiology
Identifiers
urn:nbn:se:ri:diva-68831 (URN)10.1016/j.wasman.2023.11.039 (DOI)2-s2.0-85180417079 (Scopus ID)
Note

The authors would like to thank Bio4Energy, a strategic research environment appointed by the Swedish government, for supporting this work. We also thank the Industrial Doctoral School for Research and Innovation of Umeå University (Sweden), and Vatten och Avfallskompetens I Norr AB (Vakin AB), for supporting this work. We thank VAKIN for providing the sewage sludge, and the Swedish University of Agricultural Sciences (SLU) (Sweden) for providing the microalgae. We specifically thank Francesco Gentili and Johan Sandgren for the sampling of microalgae and sewage sludge, respectively, and Pär Jonsson for processing GC-MS data.

Available from: 2024-01-08 Created: 2024-01-08 Last updated: 2024-01-11Bibliographically approved
Sun, J., Benavente, V., Jansson, S. & Mašek, O. (2023). Comparative characterisation and phytotoxicity assessment of biochar and hydrochar derived from municipal wastewater microalgae biomass. Bioresource Technology, 386, Article ID 129567.
Open this publication in new window or tab >>Comparative characterisation and phytotoxicity assessment of biochar and hydrochar derived from municipal wastewater microalgae biomass
2023 (English)In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 386, article id 129567Article in journal (Refereed) Published
Abstract [en]

Microalgae, originating from a tertiary treatment of municipal wastewater, is considered a sustainable feedstock for producing biochar and hydrochar, offering great potential for agricultural use due to nutrient content and carbon storage ability. However, there are risks related to contamination and these need to be carefully assessed to ensure safe use of material from wastewater microalgae. Therefore, this study compared the properties and phototoxicity of biochar and hydrochar produced via pyrolysis and hydrothermal carbonisation (HTC) of microalgae under different temperatures and residence times. While biochar promoted germination and seedling growth by up to 11.0% and 70.0%, respectively, raw hydrochar showed strong phytotoxicity, due to the high content of volatile matter. Two post-treatments, dichloromethane (DCM) washing and further pyrolysis, proved to be effective methods for mitigating phytotoxicity of hydrochar. Additionally, biochar had 35.8–38.6% fixed carbon, resulting in higher carbon sequestration potential compared to hydrochar. © 2023 The Author(s)

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Carbonization, Dichloromethane, Microorganisms, Pyrolysis, Risk assessment, Wastewater treatment, Agricultural use, Biochar, Carbon storage, Comparative characterizations, Micro-algae, Municipal wastewaters, Nutrient contents, Property, Storage abilities, Tertiary treatment, biomass, carbon sequestration, germination, nutrient, phytotoxicity, wastewater, Microalgae
National Category
Environmental Sciences
Identifiers
urn:nbn:se:ri:diva-65929 (URN)10.1016/j.biortech.2023.129567 (DOI)2-s2.0-85166234174 (Scopus ID)
Note

Funding sponsor: Scottish Alliance for Geoscience, Environment and Society.

Available from: 2023-08-24 Created: 2023-08-24 Last updated: 2023-12-28Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3252-467X

Search in DiVA

Show all publications