IDEAS home Printed from https://ideas.repec.org/a/gam/jeners/v18y2025i17p4568-d1736442.html
   My bibliography  Save this article

Selective Extraction and Hydrotreatment of Biocrude from Sewage Sludge: Toward High-Yield, Alkane-Rich, Low-Heteroatom Biofuels

Author

Listed:
  • Muhammad Usman

    (Department of Transdisciplinary Science and Engineering, School of Environment and Society, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan)

  • Shuo Cheng

    (Department of Transdisciplinary Science and Engineering, School of Environment and Society, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan)

  • Sasipa Boonyubol

    (Department of Transdisciplinary Science and Engineering, School of Environment and Society, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan)

  • Muhammad Aziz

    (Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
    Faculty of Mathematics and Science, Universitas Negeri Malang, Jl. Semarang 5, Malang 65145, Indonesia)

  • Jeffrey S. Cross

    (Department of Transdisciplinary Science and Engineering, School of Environment and Society, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan)

Abstract

This study investigates the hydrothermal liquefaction (HTL) of sewage sludge across a temperature range of 250–375 °C, combined with selective solvent extraction and catalytic hydrotreatment to produce high-quality biocrude. Four solvents including dichloromethane (DCM), hexane, ethyl butyrate (EB), and ethyl acetate (EA), were used to evaluate temperature-dependent extraction performance and product quality. Biocrude yields increased from 250 °C to a maximum at 350 °C for all solvents: hexane (9.3–18.1%), DCM (16.3–49.7%), EB (17.6–50.1%), and EA (9.6–23.5%). A yield decline was observed at 375 °C due to secondary cracking and gasification. Elemental analysis revealed that hexane and EB extracts had higher carbon (up to 61.6 wt%) and hydrogen contents, while DCM retained the most nitrogen (up to 3.96 wt%) due to its polarity. Sulfur remained below 0.5 wt% in all biocrudes. GC–MS analysis of 350 °C biocrudes showed fatty acids as dominant components (43–53%), especially palmitic acid, along with ketones, amides, and heterocyclic compounds. Hydrotreatment using Ni/SiO 2 –Al 2 O 3 significantly enhanced biocrude quality by increasing alkane content by 40–60% and reducing nitrogen levels by up to 75%, with higher heating values reaching 38–44 MJ/kg. These findings demonstrate the integrated potential of HTL process tuning, green solvent extraction, and catalytic upgrading for converting sewage sludge into cleaner, energy-dense biofuels.

Suggested Citation

  • Muhammad Usman & Shuo Cheng & Sasipa Boonyubol & Muhammad Aziz & Jeffrey S. Cross, 2025. "Selective Extraction and Hydrotreatment of Biocrude from Sewage Sludge: Toward High-Yield, Alkane-Rich, Low-Heteroatom Biofuels," Energies, MDPI, vol. 18(17), pages 1-21, August.
    • Handle: RePEc:gam:jeners:v:18:y:2025:i:17:p:4568-:d:1736442
    as

    Download full text from publisher

    File URL: https://www.mdpi.com/1996-1073/18/17/4568/pdf
    Download Restriction: no
    File URL: https://www.mdpi.com/1996-1073/18/17/4568/
    Download Restriction: no
    ---><---

    References listed on IDEAS

    as
    1. de Jesus, Sérgio S. & Filho, Rubens Maciel, 2020. "Recent advances in lipid extraction using green solvents," Renewable and Sustainable Energy Reviews, Elsevier, vol. 133(C).
    2. Zhu, Zhe & Toor, Saqib Sohail & Rosendahl, Lasse & Yu, Donghong & Chen, Guanyi, 2015. "Influence of alkali catalyst on product yield and properties via hydrothermal liquefaction of barley straw," Energy, Elsevier, vol. 80(C), pages 284-292.
    3. Jahromi, Hossein & Agblevor, Foster A., 2017. "Upgrading of pinyon-juniper catalytic pyrolysis oil via hydrodeoxygenation," Energy, Elsevier, vol. 141(C), pages 2186-2195.
    4. Xu, Donghai & Lin, Guike & Liu, Liang & Wang, Yang & Jing, Zefeng & Wang, Shuzhong, 2018. "Comprehensive evaluation on product characteristics of fast hydrothermal liquefaction of sewage sludge at different temperatures," Energy, Elsevier, vol. 159(C), pages 686-695.
    5. Gil, A. & Siles, J.A. & Martín, M.A. & Chica, A.F. & Estévez-Pastor, F.S. & Toro-Baptista, E., 2018. "Effect of microwave pretreatment on semi-continuous anaerobic digestion of sewage sludge," Renewable Energy, Elsevier, vol. 115(C), pages 917-925.
    6. Maria Cristina Collivignarelli & Alessandro Abbà & Andrea Frattarola & Marco Carnevale Miino & Sergio Padovani & Ioannis Katsoyiannis & Vincenzo Torretta, 2019. "Legislation for the Reuse of Biosolids on Agricultural Land in Europe: Overview," Sustainability, MDPI, vol. 11(21), pages 1-22, October.
    7. Elalami, D. & Carrere, H. & Monlau, F. & Abdelouahdi, K. & Oukarroum, A. & Barakat, A., 2019. "Pretreatment and co-digestion of wastewater sludge for biogas production: Recent research advances and trends," Renewable and Sustainable Energy Reviews, Elsevier, vol. 114(C), pages 1-1.
    Full references (including those not matched with items on IDEAS)

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Kumar, R. & Strezov, V., 2021. "Thermochemical production of bio-oil: A review of downstream processing technologies for bio-oil upgrading, production of hydrogen and high value-added products," Renewable and Sustainable Energy Reviews, Elsevier, vol. 135(C).
    2. Qian, Lili & Wang, Shuzhong & Savage, Phillip E., 2020. "Fast and isothermal hydrothermal liquefaction of sludge at different severities: Reaction products, pathways, and kinetics," Applied Energy, Elsevier, vol. 260(C).
    3. Song, Xueyi & Yuan, Junjie & Yang, Chen & Deng, Gaofeng & Wang, Zhichao & Gao, Jubao, 2023. "Carbon dioxide separation performance evaluation of amine-based versus choline-based deep eutectic solvents," Renewable and Sustainable Energy Reviews, Elsevier, vol. 184(C).
    4. Justyna Górka & Małgorzata Cimochowicz-Rybicka & Dominika Poproch, 2022. "Sludge Management at the Kraków-Płaszów WWTP—Case Study," Sustainability, MDPI, vol. 14(13), pages 1-11, June.
    5. Jaiswal, Krishna Kumar & Dutta, Swapnamoy & Banerjee, Ishita & Jaiswal, Km Smriti & Renuka, Nirmal & Ratha, Sachitra Kumar & Jaiswal, Amit K., 2024. "Valorization of fish processing industry waste for biodiesel production: Opportunities, challenges, and technological perspectives," Renewable Energy, Elsevier, vol. 220(C).
    6. Ochoa, Aitor & Vicente, Héctor & Sierra, Irene & Arandes, José M. & Castaño, Pedro, 2020. "Implications of feeding or cofeeding bio-oil in the fluid catalytic cracker (FCC) in terms of regeneration kinetics and energy balance," Energy, Elsevier, vol. 209(C).
    7. Wang, Jing & Liu, Sitong & Feng, Kun & Lou, Yu & Ma, Jun & Xing, Defeng, 2025. "Anaerobic digestion of lignocellulosic biomass: Process intensification and artificial intelligence," Renewable and Sustainable Energy Reviews, Elsevier, vol. 210(C).
    8. Elvira E. Ziganshina & Svetlana S. Bulynina & Ayrat M. Ziganshin, 2022. "Impact of Granular Activated Carbon on Anaerobic Process and Microbial Community Structure during Mesophilic and Thermophilic Anaerobic Digestion of Chicken Manure," Sustainability, MDPI, vol. 14(1), pages 1-20, January.
    9. Giuseppe Campo & Alberto Cerutti & Claudio Lastella & Aldo Leo & Deborah Panepinto & Mariachiara Zanetti & Barbara Ruffino, 2021. "Production and Destination of Sewage Sludge in the Piemonte Region (Italy): The Results of a Survey for a Future Sustainable Management," IJERPH, MDPI, vol. 18(7), pages 1-13, March.
    10. Tahir H. Seehar & Saqib S. Toor & Ayaz A. Shah & Thomas H. Pedersen & Lasse A. Rosendahl, 2020. "Biocrude Production from Wheat Straw at Sub and Supercritical Hydrothermal Liquefaction," Energies, MDPI, vol. 13(12), pages 1-18, June.
    11. Andrade Díaz, Christhel & Albers, Ariane & Zamora-Ledezma, Ezequiel & Hamelin, Lorie, 2024. "The interplay between bioeconomy and the maintenance of long-term soil organic carbon stock in agricultural soils: A systematic review," Renewable and Sustainable Energy Reviews, Elsevier, vol. 189(PA).
    12. Artur Wodołażski, 2025. "Coupled CFD-DEM Numerical Simulation of Hydrothermal Liquefaction (HTL) of Sludge Flocs to Biocrude Oil in a Continuous Stirred Tank Reactor (CSTR) in a Scale-Up Study," Energies, MDPI, vol. 18(17), pages 1-26, August.
    13. Chen, Yi-di & Li, Suping & Ho, Shih-Hsin & Wang, Chengyu & Lin, Yen-Chang & Nagarajan, Dillirani & Chang, Jo-Shu & Ren, Nan-qi, 2018. "Integration of sludge digestion and microalgae cultivation for enhancing bioenergy and biorefinery," Renewable and Sustainable Energy Reviews, Elsevier, vol. 96(C), pages 76-90.
    14. Christine Peyrelasse & Abdellatif Barakat & Camille Lagnet & Prasad Kaparaju & Florian Monlau, 2021. "Anaerobic Digestion of Wastewater Sludge and Alkaline-Pretreated Wheat Straw at Semi-Continuous Pilot Scale: Performances and Energy Assessment," Energies, MDPI, vol. 14(17), pages 1-15, August.
    15. Ly, Hoang Vu & Lim, Dong-Hyeon & Sim, Jae Wook & Kim, Seung-Soo & Kim, Jinsoo, 2018. "Catalytic pyrolysis of tulip tree (Liriodendron) in bubbling fluidized-bed reactor for upgrading bio-oil using dolomite catalyst," Energy, Elsevier, vol. 162(C), pages 564-575.
    16. Salah Jellali & Yassine Charabi & Muhammad Usman & Abdullah Al-Badi & Mejdi Jeguirim, 2021. "Investigations on Biogas Recovery from Anaerobic Digestion of Raw Sludge and Its Mixture with Agri-Food Wastes: Application to the Largest Industrial Estate in Oman," Sustainability, MDPI, vol. 13(7), pages 1-20, March.
    17. Muhammad Usman & Shuo Cheng & Sasipa Boonyubol & Jeffrey S. Cross, 2023. "Evaluating Green Solvents for Bio-Oil Extraction: Advancements, Challenges, and Future Perspectives," Energies, MDPI, vol. 16(15), pages 1-45, August.
    18. Parisa Heidarnejad & Hadi Genceli & Nasim Hashemian & Mustafa Asker & Mohammad Al-Rawi, 2024. "Biomass-Fueled Organic Rankine Cycles: State of the Art and Future Trends," Energies, MDPI, vol. 17(15), pages 1-30, August.
    19. Georgia-Christina Mitraka & Konstantinos N. Kontogiannopoulos & Maria Batsioula & George F. Banias & Anastasios I. Zouboulis & Panagiotis G. Kougias, 2022. "A Comprehensive Review on Pretreatment Methods for Enhanced Biogas Production from Sewage Sludge," Energies, MDPI, vol. 15(18), pages 1-56, September.
    20. Imai, Akihisa & Hardi, Flabianus & Lundqvist, Petter & Furusjö, Erik & Kirtania, Kawnish & Karagöz, Selhan & Tekin, Kubilay & Yoshikawa, Kunio, 2018. "Alkali-catalyzed hydrothermal treatment of sawdust for production of a potential feedstock for catalytic gasification," Applied Energy, Elsevier, vol. 231(C), pages 594-599.

    More about this item

    Keywords

    ;
    ;
    ;
    ;
    ;
    ;
    ;
    ;
    ;
    ;
    ;

    Statistics

    Access and download statistics

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:gam:jeners:v:18:y:2025:i:17:p:4568-:d:1736442. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: MDPI Indexing Manager (email available below). General contact details of provider: https://www.mdpi.com .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.