IDEAS home Printed from https://ideas.repec.org/a/gam/jsusta/v17y2025i16p7545-d1729293.html
   My bibliography  Save this article

Enhancing Wastewater Treatment Sustainability Through Integrated Anaerobic Digestion and Hydrothermal Carbonization: A Life-Cycle Perspective

Author

Listed:
  • Kayode J. Taiwo

    (Department of Food Science and Technology, University of Georgia, 100 Cedar Street, Athens, GA 30602, USA
    These authors contributed equally to this work.)

  • Andrada V. Oancea

    (Environmental Biotechnology Group, Department of Geosciences, University of Tübingen, 94–96 Schnarrenbergstr, 72076 Tübingen, Germany
    These authors contributed equally to this work.)

  • Nithya Sree Kotha

    (Department of Food Science and Technology, University of Georgia, 100 Cedar Street, Athens, GA 30602, USA)

  • Joseph G. Usack

    (Department of Food Science and Technology, University of Georgia, 100 Cedar Street, Athens, GA 30602, USA
    New Materials Institute, University of Georgia, 220 Riverbend Rd, Athens, GA 30602, USA
    Institute for Integrative Agriculture, Office of Research, University of Georgia, 130 Coverdell Center, 500 D.W. Brooks Dr., Athens, GA 30602, USA)

Abstract

Wastewater treatment plants (WWTPs) are critical infrastructure that lessen the environmental impacts of human activity by stabilizing wastewaters laden with organics, chemicals, and nutrients. WWTPs face an increasing global population, greater wastewater volumes, stricter environmental regulations, and additional societal pressures to implement more sustainable and energy-efficient waste management strategies. WWTPs are energy-intensive facilities that generate significant GHG emissions and involve high operational costs. Therefore, improving the process efficiency can lead to widespread environmental and economic benefits. One promising approach is to integrate anaerobic digestion (AD) with hydrothermal carbonization (HTC) to enhance sludge treatment, optimize energy recovery, create valuable bio-based materials, and minimize sludge disposal. This study employs an LCA to evaluate the environmental impact of coupling HTC with AD compared to conventional AD treatment. HTC degrades wastewater sludge in an aqueous medium, producing carbon-dense hydrochar while reducing sludge volumes. HTC also generates an aqueous byproduct containing >30% of the original carbon as simple organics. In this system model, the aqueous byproduct is returned to AD to generate additional biogas, which then provides heat and power for the WWTP and HTC process. The results indicate that the integrated AD + HTC system significantly reduces environmental emissions and sludge volumes, increases net energy recovery, and improves wastewater sludge valorization compared to conventional AD. This research highlights the potential of AD + HTC as a key circular bioeconomy strategy, offering an innovative and efficient solution for advancing the sustainability of WWTPs.

Suggested Citation

  • Kayode J. Taiwo & Andrada V. Oancea & Nithya Sree Kotha & Joseph G. Usack, 2025. "Enhancing Wastewater Treatment Sustainability Through Integrated Anaerobic Digestion and Hydrothermal Carbonization: A Life-Cycle Perspective," Sustainability, MDPI, vol. 17(16), pages 1-20, August.
    • Handle: RePEc:gam:jsusta:v:17:y:2025:i:16:p:7545-:d:1729293
    as

    Download full text from publisher

    File URL: https://www.mdpi.com/2071-1050/17/16/7545/pdf
    Download Restriction: no
    File URL: https://www.mdpi.com/2071-1050/17/16/7545/
    Download Restriction: no
    ---><---

    References listed on IDEAS

    as
    1. Małgorzata Wilk & Marcin Gajek & Maciej Śliz & Klaudia Czerwińska & Lidia Lombardi, 2022. "Hydrothermal Carbonization Process of Digestate from Sewage Sludge: Chemical and Physical Properties of Hydrochar in Terms of Energy Application," Energies, MDPI, vol. 15(18), pages 1-17, September.
    2. Manfredi Picciotto Maniscalco & Maurizio Volpe & Antonio Messineo, 2020. "Hydrothermal Carbonization as a Valuable Tool for Energy and Environmental Applications: A Review," Energies, MDPI, vol. 13(16), pages 1-26, August.
    3. Michael Schäfer & Oliver Gretzschel & Heidrun Steinmetz, 2020. "The Possible Roles of Wastewater Treatment Plants in Sector Coupling," Energies, MDPI, vol. 13(8), pages 1-20, April.
    4. Fytili, D. & Zabaniotou, A., 2008. "Utilization of sewage sludge in EU application of old and new methods--A review," Renewable and Sustainable Energy Reviews, Elsevier, vol. 12(1), pages 116-140, January.
    5. Aragón-Briceño, C.I. & Ross, A.B. & Camargo-Valero, M.A., 2021. "Mass and energy integration study of hydrothermal carbonization with anaerobic digestion of sewage sludge," Renewable Energy, Elsevier, vol. 167(C), pages 473-483.
    6. Mitchell Ubene & Mohammad Heidari & Animesh Dutta, 2022. "Computational Modeling Approaches of Hydrothermal Carbonization: A Critical Review," Energies, MDPI, vol. 15(6), pages 1-28, March.
    7. Jumoke Oladejo & Kaiqi Shi & Xiang Luo & Gang Yang & Tao Wu, 2018. "A Review of Sludge-to-Energy Recovery Methods," Energies, MDPI, vol. 12(1), pages 1-38, December.
    8. Panepinto, Deborah & Fiore, Silvia & Zappone, Mariantonia & Genon, Giuseppe & Meucci, Lorenza, 2016. "Evaluation of the energy efficiency of a large wastewater treatment plant in Italy," Applied Energy, Elsevier, vol. 161(C), pages 404-411.
    Full references (including those not matched with items on IDEAS)

    Citations

    Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.
    as


    Cited by:

    1. Mu Wang & Yan Zhao & Zongsheng An & Changming Dou, 2025. "Activation of Persulfate by Sulfide-Modified Nanoscale Zero-Valent Iron Supported on Biochar for 2,4-Dichlorophenol Degradation: Efficiency, Sustainability, and Mechanism Investigation," Sustainability, MDPI, vol. 17(19), pages 1-17, September.

    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. Diego Teixeira Michalovicz & Patricia Bilotta, 2023. "Impact of a methane emission tax on circular economy scenarios in small wastewater treatment plants," Environment, Development and Sustainability: A Multidisciplinary Approach to the Theory and Practice of Sustainable Development, Springer, vol. 25(7), pages 6575-6589, July.
    2. Sanja Potrč & Aleksandra Petrovič & Jafaru M. Egieya & Lidija Čuček, 2025. "Valorization of Biomass Through Anaerobic Digestion and Hydrothermal Carbonization: Integrated Process Flowsheet and Supply Chain Network Optimization," Energies, MDPI, vol. 18(2), pages 1-24, January.
    3. Oumaima Mabrouk & Helmi Hamdi & Sami Sayadi & Mohammad A. Al-Ghouti & Mohammed H. Abu-Dieyeh & Nabil Zouari, 2023. "Reuse of Sludge as Organic Soil Amendment: Insights into the Current Situation and Potential Challenges," Sustainability, MDPI, vol. 15(8), pages 1-25, April.
    4. Agnieszka Urbanowska & Małgorzata Kabsch-Korbutowicz & Christian Aragon-Briceño & Mateusz Wnukowski & Artur Pożarlik & Lukasz Niedzwiecki & Marcin Baranowski & Michał Czerep & Przemysław Seruga & Hali, 2021. "Cascade Membrane System for Separation of Water and Organics from Liquid By-Products of HTC of the Agricultural Digestate—Evaluation of Performance," Energies, MDPI, vol. 14(16), pages 1-18, August.
    5. Andrea Salimbeni & Marta Di Bianca & Andrea Maria Rizzo & David Chiaramonti, 2023. "Activated Carbon and P-Rich Fertilizer Production from Industrial Sludge by Application of an Integrated Thermo-Chemical Treatment," Sustainability, MDPI, vol. 15(19), pages 1-24, October.
    6. Giuseppe Maggiotto & Gianpiero Colangelo & Marco Milanese & Arturo de Risi, 2023. "Thermochemical Technologies for the Optimization of Olive Wood Biomass Energy Exploitation: A Review," Energies, MDPI, vol. 16(19), pages 1-17, September.
    7. Dilvin Cebi & Melih Soner Celiktas & Hasan Sarptas, 2022. "A Review on Sewage Sludge Valorization via Hydrothermal Carbonization and Applications for Circular Economy," Circular Economy and Sustainability, Springer, vol. 2(4), pages 1345-1367, December.
    8. Tiago Teribele & Maria Elizabeth Gemaque Costa & Conceição de Maria Sales da Silva & Lia Martins Pereira & Lucas Pinto Bernar & Douglas Alberto Rocha de Castro & Fernanda Paula da Costa Assunção & Mar, 2023. "Hydrothermal Carbonization of Corn Stover: Structural Evolution of Hydro-Char and Degradation Kinetics," Energies, MDPI, vol. 16(7), pages 1-22, April.
    9. Shahbeig, Hossein & Nosrati, Mohsen, 2020. "Pyrolysis of municipal sewage sludge for bioenergy production: Thermo-kinetic studies, evolved gas analysis, and techno-socio-economic assessment," Renewable and Sustainable Energy Reviews, Elsevier, vol. 119(C).
    10. Sanchez, M.E. & Otero, M. & Gómez, X. & Morán, A., 2009. "Thermogravimetric kinetic analysis of the combustion of biowastes," Renewable Energy, Elsevier, vol. 34(6), pages 1622-1627.
    11. Adam Masłoń & Joanna Czarnota & Paulina Szczyrba & Aleksandra Szaja & Joanna Szulżyk-Cieplak & Grzegorz Łagód, 2024. "Assessment of Energy Self-Sufficiency of Wastewater Treatment Plants—A Case Study from Poland," Energies, MDPI, vol. 17(5), pages 1-19, March.
    12. Jiawen Zhang & Zhiyi Liang & Toru Matsumoto & Tiejia Zhang, 2022. "Environmental and Economic Implication of Implementation Scale of Sewage Sludge Recycling Systems Considering Carbon Trading Price," Sustainability, MDPI, vol. 14(14), pages 1-16, July.
    13. Bidart, Christian & Fröhling, Magnus & Schultmann, Frank, 2014. "Electricity and substitute natural gas generation from the conversion of wastewater treatment plant sludge," Applied Energy, Elsevier, vol. 113(C), pages 404-413.
    14. Junshen Qu & Daiying Wang & Zeyu Deng & Hejie Yu & Jianjun Dai & Xiaotao Bi, 2023. "Biochar Prepared by Microwave-Assisted Co-Pyrolysis of Sewage Sludge and Cotton Stalk: A Potential Soil Conditioner," Sustainability, MDPI, vol. 15(9), pages 1-18, April.
    15. Vishwajeet & Halina Pawlak-Kruczek & Marcin Baranowski & Michał Czerep & Artur Chorążyczewski & Krystian Krochmalny & Michał Ostrycharczyk & Paweł Ziółkowski & Paweł Madejski & Tadeusz Mączka & Amit A, 2022. "Entrained Flow Plasma Gasification of Sewage Sludge–Proof-of-Concept and Fate of Inorganics," Energies, MDPI, vol. 15(5), pages 1-14, March.
    16. Siti Zaharah Roslan & Siti Fairuz Zainudin & Alijah Mohd Aris & Khor Bee Chin & Mohibah Musa & Ahmad Rafizan Mohamad Daud & Syed Shatir A. Syed Hassan, 2023. "Hydrothermal Carbonization of Sewage Sludge into Solid Biofuel: Influences of Process Conditions on the Energetic Properties of Hydrochar," Energies, MDPI, vol. 16(5), pages 1-16, March.
    17. Ahmadi, Ehsan & Yousefzadeh, Samira & Mokammel, Adel & Miri, Mohammad & Ansari, Mohsen & Arfaeinia, Hossein & Badi, Mojtaba Yegane & Ghaffari, Hamid Reza & Rezaei, Soheila & Mahvi, Amir Hossein, 2020. "Kinetic study and performance evaluation of an integrated two-phase fixed-film baffled bioreactor for bioenergy recovery from wastewater and bio-wasted sludge," Renewable and Sustainable Energy Reviews, Elsevier, vol. 121(C).
    18. Rajesh Banu Jeyakumar & Godvin Sharmila Vincent, 2022. "Recent Advances and Perspectives of Nanotechnology in Anaerobic Digestion: A New Paradigm towards Sludge Biodegradability," Sustainability, MDPI, vol. 14(12), pages 1-18, June.
    19. Beegle, Jeffrey R. & Borole, Abhijeet P., 2018. "Energy production from waste: Evaluation of anaerobic digestion and bioelectrochemical systems based on energy efficiency and economic factors," Renewable and Sustainable Energy Reviews, Elsevier, vol. 96(C), pages 343-351.
    20. Leonel J. R. Nunes & Abel M. Rodrigues & João C. O. Matias & Ana I. Ferraz & Ana C. Rodrigues, 2021. "Production of Biochar from Vine Pruning: Waste Recovery in the Wine Industry," Agriculture, MDPI, vol. 11(6), pages 1-15, May.

    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:jsusta:v:17:y:2025:i:16:p:7545-:d:1729293. 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.