{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,25]],"date-time":"2026-04-25T04:30:51Z","timestamp":1777091451559,"version":"3.51.4"},"reference-count":100,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2024,5,17]],"date-time":"2024-05-17T00:00:00Z","timestamp":1715904000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Portuguese Foundation for Science and Technology","doi-asserted-by":"publisher","award":["UIDB\/05064\/2020"],"award-info":[{"award-number":["UIDB\/05064\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Portuguese Foundation for Science and Technology","doi-asserted-by":"publisher","award":["101084148"],"award-info":[{"award-number":["101084148"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"name":"European Union\u2019s Horizon Europe research and innovation programme","award":["UIDB\/05064\/2020"],"award-info":[{"award-number":["UIDB\/05064\/2020"]}]},{"name":"European Union\u2019s Horizon Europe research and innovation programme","award":["101084148"],"award-info":[{"award-number":["101084148"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Energies"],"abstract":"<jats:p>With the increase in the world population and economic activity, the production of sewage sludge has grown, and its management has become an environmental problem. The most traditional method of managing sewage sludge is to dispose of it in landfills and on farmland. One way to valorize sewage sludge is to use thermochemical conversion processes to produce added-value products such as biochar, biofuels, and renewable gases. However, due to the high moisture content, thermochemical conversion using processes such as pyrolysis and traditional gasification involves multiple pre-treatment processes such as material drying. Hydrothermal thermochemical processes usually require high pressures, which pose many challenges to their application on a large scale. In this work, the advantages and disadvantages of the different existing thermochemical processes for the recovery of sewage sludge were analyzed, as well as the resulting industrial and environmental challenges. A SWOT analysis was carried out to assess the different thermochemical processes in terms of technical feasibility, economic viability, and broader market considerations.<\/jats:p>","DOI":"10.3390\/en17102417","type":"journal-article","created":{"date-parts":[[2024,5,17]],"date-time":"2024-05-17T12:02:23Z","timestamp":1715947343000},"page":"2417","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["An Overview of the Thermochemical Valorization of Sewage Sludge: Principles and Current Challenges"],"prefix":"10.3390","volume":"17","author":[{"given":"Bruna","family":"Rijo","sequence":"first","affiliation":[{"name":"VALORIZA\u2014Research Center for Endogenous Resource Valorization, Portalegre Polytechnic University, Campus Polit\u00e9cnico 10, 7300-555 Portalegre, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5733-902X","authenticated-orcid":false,"given":"Catarina","family":"Nobre","sequence":"additional","affiliation":[{"name":"VALORIZA\u2014Research Center for Endogenous Resource Valorization, Portalegre Polytechnic University, Campus Polit\u00e9cnico 10, 7300-555 Portalegre, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2581-4460","authenticated-orcid":false,"given":"Paulo","family":"Brito","sequence":"additional","affiliation":[{"name":"VALORIZA\u2014Research Center for Endogenous Resource Valorization, Portalegre Polytechnic University, Campus Polit\u00e9cnico 10, 7300-555 Portalegre, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1951-889X","authenticated-orcid":false,"given":"Paulo","family":"Ferreira","sequence":"additional","affiliation":[{"name":"VALORIZA\u2014Research Center for Endogenous Resource Valorization, Portalegre Polytechnic University, Campus Polit\u00e9cnico 10, 7300-555 Portalegre, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,5,17]]},"reference":[{"key":"ref_1","unstructured":"(2024, February 26). Eurostat Sewage Sludge Production and Disposal. Available online: https:\/\/ec.europa.eu\/eurostat\/databrowser\/view\/HLTH_PS_PREV__custom_7978672\/bookmark\/table?lang=en&bookmarkId=827e0163-fd0f-4ed7-9cd3-f2c20574cb07%0Ahttps:\/\/ec.europa.eu\/eurostat\/databrowser\/view\/tec00118\/default\/table?lang=en%0Ahttps:\/\/ec.europa.eu\/euros."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"114615","DOI":"10.1016\/j.enconman.2021.114615","article-title":"Hydrothermal Liquefaction of Municipal Sewage Sludge: Effect of Red Mud Catalyst in Ethylene and Inert Ambiences","volume":"245","author":"Rahman","year":"2021","journal-title":"Energy Convers. Manag."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"118564","DOI":"10.1016\/j.envpol.2021.118564","article-title":"Treatment Processes to Eliminate Potential Environmental Hazards and Restore Agronomic Value of Sewage Sludge: A Review","volume":"293","author":"Hoang","year":"2022","journal-title":"Environ. Pollut."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1323","DOI":"10.1016\/j.jclepro.2016.08.014","article-title":"Thermal Valorization of Sewer Sludge: Perspectives for Large Wastewater Treatment Plants","volume":"137","author":"Panepinto","year":"2016","journal-title":"J. Clean. Prod."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1016\/j.apenergy.2015.03.132","article-title":"Energy Feasibility Study of Sludge Pretreatments: A Review","volume":"149","author":"Cano","year":"2015","journal-title":"Appl. Energy"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2566","DOI":"10.1016\/j.rser.2012.01.074","article-title":"Towards Sewage Sludge Based Biofuels via Thermochemical Conversion\u2014A Review","volume":"16","author":"Manara","year":"2012","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"888","DOI":"10.1016\/j.rser.2017.05.262","article-title":"Thermochemical Processing of Sewage Sludge to Energy and Fuel: Fundamentals, Challenges and Considerations","volume":"80","author":"Wang","year":"2017","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1016\/j.wasman.2016.04.038","article-title":"Comprehensive Characterisation of Sewage Sludge for Thermochemical Conversion Processes\u2014Based on Singapore Survey","volume":"54","author":"Chan","year":"2016","journal-title":"Waste Manag."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3389\/fceng.2023.1129783","article-title":"Wastewater and Sludge Valorisation: A Novel Approach for Treatment and Resource Recovery to Achieve Circular Economy Concept","volume":"5","author":"Kathi","year":"2023","journal-title":"Front. Chem. Eng."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"100843","DOI":"10.1016\/j.pecs.2020.100843","article-title":"Thermochemical Conversion of Sewage Sludge: A Critical Review","volume":"79","author":"Gao","year":"2020","journal-title":"Prog. Energy Combust. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"123351","DOI":"10.1016\/j.fuel.2022.123351","article-title":"Recent Advances and Viability in Sustainable Thermochemical Conversion of Sludge to Bio-Fuel Production","volume":"316","author":"Gururani","year":"2022","journal-title":"Fuel"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1016\/j.wasman.2015.04.020","article-title":"Sewage Sludge Drying Process Integration with a Waste-to-Energy Power Plant","volume":"42","author":"Bianchini","year":"2015","journal-title":"Waste Manag."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Alves, O., Garcia, B., Rijo, B., Lourinho, G., and Nobre, C. (2022). Market Opportunities in Portugal for the Water-and-Waste Sector Using Sludge Gasification. Energies, 15.","DOI":"10.3390\/en15186600"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"122259","DOI":"10.1016\/j.jclepro.2020.122259","article-title":"A Sustainable Paradigm of Sewage Sludge Biochar: Valorization, Opportunities, Challenges and Future Prospects","volume":"269","author":"Singh","year":"2020","journal-title":"J. Clean. Prod."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Durak, H. (2023). Comprehensive Assessment of Thermochemical Processes for Sustainable Waste Management and Resource Recovery. Processes, 11.","DOI":"10.3390\/pr11072092"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1016\/j.fuproc.2018.12.011","article-title":"Microwave-Assisted Pyrolysis of Sewage Sludge: A Review","volume":"187","author":"Zaker","year":"2019","journal-title":"Fuel Process. Technol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"134657","DOI":"10.1016\/j.jclepro.2022.134657","article-title":"A Review on Turning Sewage Sludge to Value-Added Energy and Materials via Thermochemical Conversion towards Carbon Neutrality","volume":"379","author":"Hu","year":"2022","journal-title":"J. Clean. Prod."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"26933","DOI":"10.1016\/j.ijhydene.2019.08.182","article-title":"Investigation on the Decomposition of Chemical Compositions during Hydrothermal Conversion of Dewatered Sewage Sludge","volume":"44","author":"Su","year":"2019","journal-title":"Int. J. Hydrogen Energy"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.wasman.2023.01.025","article-title":"Sustainability Assessment of Alternative Waste-to-Energy Technologies for the Management of Sewage Sludge","volume":"159","author":"Ronda","year":"2023","journal-title":"Waste Manag."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1016\/j.wasman.2014.10.004","article-title":"Consequences of Sludge Composition on Combustion Performance Derived from Thermogravimetry Analysis","volume":"35","author":"Li","year":"2015","journal-title":"Waste Manag."},{"key":"ref_21","first-page":"e01735","article-title":"Determining the Potential Human Health Risks Posed by Heavy Metals Present in Municipal Sewage Sludge from a Wastewater Treatment Plant","volume":"20","author":"Nyashanu","year":"2023","journal-title":"Sci. Afr."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"168856","DOI":"10.1016\/j.scitotenv.2023.168856","article-title":"The Occurrence of Heavy Metals and Antimicrobials in Sewage Sludge and Their Predicted Risk to Soil\u2014Is There Anything to Fear?","volume":"912","author":"Urbaniak","year":"2024","journal-title":"Sci. Total Environ."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1080\/26395940.2021.1947159","article-title":"Thermochemical Conversion of Sewage Sludge for Energy and Resource Recovery: Technical Challenges and Prospects","volume":"33","author":"Hu","year":"2021","journal-title":"Environ. Pollut. Bioavailab."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"123199","DOI":"10.1016\/j.fuel.2022.123199","article-title":"Review of the Application of Gasification and Combustion Technology and Waste-to-Energy Technologies in Sewage Sludge Treatment","volume":"316","author":"Quan","year":"2022","journal-title":"Fuel"},{"key":"ref_25","first-page":"103042","article-title":"Syngas Production from Municipal Sewage Sludge by Gasification Process: Effects of Fixed Bed Reactor Types and Gasification Agents on Syngas Quality","volume":"56","author":"Tezer","year":"2023","journal-title":"Sustain. Energy Technol. Assess."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"409","DOI":"10.1016\/j.enconman.2015.12.064","article-title":"Syngas Production by Catalytic In-Situ Steam Co-Gasification of Wet Sewage Sludge and Pine Sawdust","volume":"111","author":"Hu","year":"2016","journal-title":"Energy Convers. Manag."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"115553","DOI":"10.1016\/j.envres.2023.115553","article-title":"Sewage Sludge Steam Gasification over Bimetallic Mesoporous Al-MCM48 Catalysts for Efficient Hydrogen Generation","volume":"224","author":"Farooq","year":"2023","journal-title":"Environ. Res."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1016\/j.renene.2021.12.069","article-title":"Two-Stage Gasification of Dried Sewage Sludge: Effects of Gasifying Agent, Bed Material, Gas Cleaning System, and Ni-Coated Distributor on Product Gas Quality","volume":"185","author":"Jeong","year":"2022","journal-title":"Renew. Energy"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"126069","DOI":"10.1016\/j.cej.2020.126069","article-title":"Tunable Syngas Production from Two-Stage Sorption-Enhanced Steam Gasification of Sewage Sludge","volume":"404","author":"Yang","year":"2021","journal-title":"Chem. Eng. J."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"284","DOI":"10.1016\/j.ijhydene.2023.04.188","article-title":"Valorization of Sewage Sludge via Air\/Steam Gasification Using Activated Carbon and Biochar as Catalysts","volume":"54","author":"Kang","year":"2023","journal-title":"Int. J. Hydrogen Energy"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1016\/j.fuproc.2010.10.006","article-title":"Air-Steam Gasification of Sewage Sludge in a Bubbling Bed Reactor: Effect of Alumina as a Primary Catalyst","volume":"92","author":"Narros","year":"2011","journal-title":"Fuel Process. Technol."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Schmid, M., Hafner, S., Biollaz, S., Schneebeli, J., Waizmann, G., and Scheffknecht, G. (2021). Steam-Oxygen Gasification of Sewage Sludge: Reduction of Tar, H2S and COS with Limestone as Bed Additive. Biomass Bioenergy, 150.","DOI":"10.1016\/j.biombioe.2021.106100"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"108","DOI":"10.1016\/j.jaap.2013.10.009","article-title":"Characterization of the Products from the Pyrolysis of Sewage Sludge in 1 Kg\/h Rotating Cylinder Reactor","volume":"105","author":"Pedroza","year":"2014","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1410","DOI":"10.1016\/j.enconman.2019.06.025","article-title":"Effects of Sewage Sludge Organic and Inorganic Constituents on the Properties of Pyrolysis Products","volume":"196","author":"Veksha","year":"2019","journal-title":"Energy Convers. Manag."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"3447","DOI":"10.1016\/j.proci.2022.07.202","article-title":"Pyrolysis of Sewage Sludge under Conditions Relevant to Applied Smouldering Combustion","volume":"39","author":"Feng","year":"2023","journal-title":"Proc. Combust. Inst."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/j.jaap.2013.10.002","article-title":"Thermal Analysis and Products Distribution of Dried Sewage Sludge Pyrolysis","volume":"105","author":"Gao","year":"2014","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1016\/j.wasman.2020.07.013","article-title":"Catalytic Co-Pyrolysis of Sewage Sludge and Rice Husk over Biochar Catalyst: Bio-Oil Upgrading and Catalytic Mechanism","volume":"114","author":"Qiu","year":"2020","journal-title":"Waste Manag."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"35874","DOI":"10.1007\/s11356-018-1463-y","article-title":"Pyrolysis of Wastewater Sludge and Composted Organic Fines from Municipal Solid Waste: Laboratory Reactor Characterisation and Product Distribution","volume":"25","author":"Agar","year":"2018","journal-title":"Environ. Sci. Pollut. Res."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1016\/j.fuproc.2016.04.015","article-title":"Characterization of the Bio-Oil Obtained by Fast Pyrolysis of Sewage Sludge in a Conical Spouted Bed Reactor","volume":"149","author":"Alvarez","year":"2016","journal-title":"Fuel Process. Technol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"5376","DOI":"10.1021\/ie7017788","article-title":"Sewage Sludge Pyrolysis in Fluidized Bed, 1: Influence of Operational Conditions on the Product Distribution","volume":"47","author":"Fonts","year":"2008","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.jes.2014.10.010","article-title":"Effects of Temperature and Composite Alumina on Pyrolysis of Sewage Sludge","volume":"30","author":"Sun","year":"2015","journal-title":"J. Environ. Sci."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1016\/j.scitotenv.2019.02.320","article-title":"Effect of Catalysts on Distribution of Polycyclic-Aromatic Hydrocarbon (PAHs) in Bio-Oils from the Pyrolysis of Dewatered Sewage Sludge at High and Low Temperatures","volume":"667","author":"Hu","year":"2019","journal-title":"Sci. Total Environ."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"835","DOI":"10.1016\/j.joei.2018.06.015","article-title":"The Effects of Fe2O3 Catalyst on the Conversion of Organic Matter and Bio-Fuel Production during Pyrolysis of Sewage Sludge","volume":"92","author":"Huang","year":"2019","journal-title":"J. Energy Inst."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"974","DOI":"10.1038\/s41598-020-79658-4","article-title":"Induced Changes of Pyrolysis Temperature on the Physicochemical Traits of Sewage Sludge and on the Potential Ecological Risks","volume":"11","author":"Bomfim","year":"2021","journal-title":"Sci. Rep."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1016\/j.biortech.2017.02.015","article-title":"Ex-Situ Catalytic Pyrolysis of Wastewater Sewage Sludge\u2014A Micro-Pyrolysis Study","volume":"232","author":"Wang","year":"2017","journal-title":"Bioresour. Technol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"252","DOI":"10.1016\/j.fuproc.2014.10.014","article-title":"Catalytic Post-Treatment of the Vapors from Sewage Sludge Pyrolysis by Means of \u03b3-Al2O3: Effect on the Liquid Product Properties","volume":"130","author":"Azuara","year":"2015","journal-title":"Fuel Process. Technol."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/S0165-2370(99)00023-6","article-title":"Thermolytical Treatment of Dried Sewage Sludge and Other Biogenic Materials-Including Upgrading of Pyrolysis Vapours by a Cracking Catalyst and Examination of Heavy Metals by X-Ray Fluorescence","volume":"50","author":"Beckers","year":"1999","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"141039","DOI":"10.1016\/j.cej.2022.141039","article-title":"Study on the Multiple Roles of CaO on Nitrogen Evolution Mechanism of Protein inside Sewage Sludge Pyrolysis","volume":"458","author":"Meng","year":"2023","journal-title":"Chem. Eng. J."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/j.coesh.2020.02.008","article-title":"A Perspective on Hydrothermal Processing of Sewage Sludge","volume":"14","author":"Chen","year":"2020","journal-title":"Curr. Opin. Environ. Sci. Health"},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Lachos-Perez, D., C\u00e9sar Torres-Mayanga, P., Abaide, E.R., Zabot, G.L., and De Castilhos, F. (2022). Hydrothermal Carbonization and Liquefaction: Differences, Progress, Challenges, and Opportunities. Bioresour. Technol., 343.","DOI":"10.1016\/j.biortech.2021.126084"},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Romano, P., Stampone, N., and Di Giacomo, G. (2023). Evolution and Prospects of Hydrothermal Carbonization. Energies, 16.","DOI":"10.3390\/en16073125"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"318","DOI":"10.1016\/j.biortech.2014.11.096","article-title":"Hydrothermal Carbonisation of Sewage Sludge: Effect of Process Conditions on Product Characteristics and Methane Production","volume":"177","author":"Shama","year":"2015","journal-title":"Bioresour. Technol."},{"key":"ref_53","first-page":"199","article-title":"Hydrothermal Carbonization as an Efficient Tool for Sewage Sludge Valorization and Phosphorous Recovery","volume":"80","author":"Volpe","year":"2020","journal-title":"Chem. Eng. Trans."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"128807","DOI":"10.1016\/j.fuel.2023.128807","article-title":"Hydrothermal Co-Carbonization of Sewage Sludge and Whey: Enhancement of Product Properties and Potential Application in Agriculture","volume":"350","author":"Vohl","year":"2023","journal-title":"Fuel"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"118820","DOI":"10.1016\/j.jenvman.2023.118820","article-title":"The Effect of an Acid Catalyst on the Hydrothermal Carbonization of Sewage Sludge","volume":"345","author":"Wilk","year":"2023","journal-title":"J. Environ. Manag."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"110788","DOI":"10.1016\/j.jece.2023.110788","article-title":"Hydrothermal Carbonization of Sewage Sludge Coupled with Fenton Oxidation Pretreatment: Moderate Oxidation to Enhance Hydrochar Yield and Properties","volume":"11","author":"Wang","year":"2023","journal-title":"J. Environ. Chem. Eng."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"105315","DOI":"10.1016\/j.arabjc.2023.105315","article-title":"Co-Hydrothermally Carbonized Sewage Sludge and Lignocellulosic Biomass: An Efficiently Renewable Solid Fuel","volume":"16","author":"Piboonudomkarn","year":"2023","journal-title":"Arab. J. Chem."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1016\/j.matpr.2022.11.107","article-title":"Conversion of Sewage Sludge from Industrial Wastewater Treatment to Solid Fuel through Hydrothermal Carbonization Process","volume":"75","author":"Paiboonudomkarn","year":"2022","journal-title":"Mater. Today Proc."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"117994","DOI":"10.1016\/j.jenvman.2023.117994","article-title":"de Co-Hydrothermal Carbonization of Pine Residual Sawdust and Non-Dewatered Sewage Sludge\u2013Effect of Reaction Conditions on Hydrochar Characteristics","volume":"340","author":"Cavali","year":"2023","journal-title":"J. Environ. Manag."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"429","DOI":"10.1016\/j.wasman.2023.11.039","article-title":"Co-Hydrothermal Carbonization of Microalgae and Digested Sewage Sludge: Assessing the Impact of Mixing Ratios on the Composition of Primary and Secondary Char","volume":"174","author":"Benavente","year":"2024","journal-title":"Waste Manag."},{"key":"ref_61","doi-asserted-by":"crossref","unstructured":"Huezo, L., Vasco-Correa, J., and Shah, A. (2021). Hydrothermal Carbonization of Anaerobically Digested Sewage Sludge for Hydrochar Production. Bioresour. Technol. Rep., 15.","DOI":"10.1016\/j.biteb.2021.100795"},{"key":"ref_62","doi-asserted-by":"crossref","unstructured":"Fan, Y., Hornung, U., and Dahmen, N. (2022). Hydrothermal Liquefaction of Sewage Sludge for Biofuel Application: A Review on Fundamentals, Current Challenges and Strategies. Biomass Bioenergy, 165.","DOI":"10.1016\/j.biombioe.2022.106570"},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"171023","DOI":"10.1016\/j.scitotenv.2024.171023","article-title":"Distribution Characteristics and Migration Pathways of Metals during Hydrothermal Liquefaction of Municipal Sewage Sludge in the Presence of Various Catalysts","volume":"920","author":"Basa","year":"2024","journal-title":"Sci. Total Environ."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"e26287","DOI":"10.1016\/j.heliyon.2024.e26287","article-title":"Hydrothermal Liquefaction of Sewage Sludge: Use of HCOOH and KOH to Improve the Slurry Pumpability in a Continuously Operated Plant","volume":"10","author":"Prestigiacomo","year":"2024","journal-title":"Heliyon"},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"139470","DOI":"10.1016\/j.jclepro.2023.139470","article-title":"Catalytic Hydrothermal Co-Liquefaction of Sewage Sludge and Agricultural Biomass for Promoting Advanced Biocrude Production","volume":"428","author":"Zhang","year":"2023","journal-title":"J. Clean. Prod."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1016\/j.joei.2022.04.008","article-title":"Catalytic Hydrothermal Liquefaction of Sewage Sludge: Effect of Metal Support Heterogeneous Catalysts on Products Distribution","volume":"103","author":"Zhu","year":"2022","journal-title":"J. Energy Inst."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3389\/fenvs.2022.996353","article-title":"Comparative Investigation on the Value-Added Products Obtained from Continuous and Batch Hydrothermal Liquefaction of Sewage Sludge","volume":"10","author":"Fan","year":"2022","journal-title":"Front. Environ. Sci."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"116101","DOI":"10.1016\/j.watres.2020.116101","article-title":"Hydrothermal Liquefaction of Sewage Sludge; Energy Considerations and Fate of Micropollutants during Pilot Scale Processing","volume":"183","author":"Carvalho","year":"2020","journal-title":"Water Res."},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1021\/acsengineeringau.1c00010","article-title":"Advanced Analytical Study of Process Streams for a Rational Optimization of Hydrothermal Gasification","volume":"1","author":"Baudouin","year":"2021","journal-title":"ACS Eng. Au"},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"1419","DOI":"10.1016\/j.joei.2020.01.004","article-title":"Valorization of Sewage Sludge through Catalytic Sub- and Supercritical Water Gasification","volume":"93","author":"Yan","year":"2020","journal-title":"J. Energy Inst."},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"121740","DOI":"10.1016\/j.energy.2021.121740","article-title":"Hydrogen Production by Sewage Sludge Gasification in Supercritical Water with High Heating Rate Batch Reactor","volume":"238","author":"Chen","year":"2022","journal-title":"Energy"},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"12991","DOI":"10.1016\/j.ijhydene.2013.03.165","article-title":"Hydrogen Production by Sewage Sludge Gasification in Supercritical Water with a Fluidized Bed Reactor","volume":"38","author":"Chen","year":"2013","journal-title":"Int. J. Hydrogen Energy"},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1016\/j.biortech.2017.10.002","article-title":"Supercritical Water Gasification of Sewage Sludge in Continuous Reactor","volume":"249","author":"Amrullah","year":"2018","journal-title":"Bioresour. Technol."},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"107727","DOI":"10.1016\/j.fuproc.2023.107727","article-title":"Migration of Nitrogen and Phosphorus during Supercritical Water Gasification of Sewage Sludge: Effect of Alkaline Additives","volume":"245","author":"Cui","year":"2023","journal-title":"Fuel Process. Technol."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1016\/j.wasman.2019.07.023","article-title":"Hydrogen Production and Phosphorus Recovery via Supercritical Water Gasification of Sewage Sludge in a Batch Reactor","volume":"96","author":"Weijin","year":"2019","journal-title":"Waste Manag."},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/j.psep.2019.08.035","article-title":"Assessment of Sewage Sludge Gasification in Supercritical Water for H2-Rich Syngas Production","volume":"131","author":"Hantoko","year":"2019","journal-title":"Process Saf. Environ. Prot."},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"459","DOI":"10.2298\/TSCI170921258X","article-title":"Economical Feasibility of Bio-Oil Production from Sewage Sludge through Pyrolysis","volume":"22","author":"Xin","year":"2018","journal-title":"Therm. Sci."},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"17988","DOI":"10.1021\/acs.est.2c06083","article-title":"Life Cycle Assessment and Cost-Benefit Analysis of Technologies in Water Resource Recovery Facilities: The Case of Sludge Pyrolysis","volume":"56","author":"Damgaard","year":"2022","journal-title":"Environ. Sci. Technol."},{"key":"ref_79","doi-asserted-by":"crossref","unstructured":"Farru, G., Scheufele, F.B., Paniagua, D.M., Keller, F., Jeong, C., and Basso, D. (2024). Business and Market Analysis of Hydrothermal Carbonization Process: Roadmap toward Implementation. Agronomy, 14.","DOI":"10.3390\/agronomy14030541"},{"key":"ref_80","doi-asserted-by":"crossref","first-page":"1127","DOI":"10.1016\/j.rser.2014.07.141","article-title":"Hydrothermal Gasification of Sewage Sludge and Model Compounds for Renewable Hydrogen Production: A Review","volume":"39","author":"He","year":"2014","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"224","DOI":"10.1016\/j.jes.2022.07.038","article-title":"Systematical Analysis of Sludge Treatment and Disposal Technologies for Carbon Footprint Reduction","volume":"128","author":"Zhao","year":"2023","journal-title":"J. Environ. Sci."},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"110367","DOI":"10.1016\/j.jenvman.2020.110367","article-title":"Thermal Treatment of Sewage Sludge in Germany: A Review","volume":"263","author":"Schnell","year":"2020","journal-title":"J. Environ. Manag."},{"key":"ref_83","doi-asserted-by":"crossref","first-page":"1598","DOI":"10.1080\/07373937.2014.910522","article-title":"Adhesion and Cohesion Characteristics of Sewage Sludge During Drying","volume":"32","author":"Li","year":"2014","journal-title":"Dry. Technol."},{"key":"ref_84","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1515\/pjct-2015-0062","article-title":"Issues Related to Waste Sewage Sludge Drying under Superheated Steam","volume":"17","author":"Hamawand","year":"2015","journal-title":"Polish J. Chem. Technol."},{"key":"ref_85","doi-asserted-by":"crossref","first-page":"1523","DOI":"10.1016\/j.jes.2014.05.019","article-title":"Experimental Study on Agitated Drying Characteristics of Sewage Sludge under the Effects of Different Additive Agents","volume":"26","author":"Deng","year":"2014","journal-title":"J. Environ. Sci."},{"key":"ref_86","doi-asserted-by":"crossref","first-page":"130383","DOI":"10.1016\/j.fuel.2023.130383","article-title":"Upgrading of Sewage Sludge-Derived Pyrolysis Oil via Hydrotreatment over NiMo-Based Catalysts","volume":"359","author":"Sukhorukov","year":"2024","journal-title":"Fuel"},{"key":"ref_87","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1016\/j.fuproc.2013.01.007","article-title":"Mathematical Modeling of Sulfur Deactivation Effects on Steam Reforming of Producer Gas Produced by Biomass Gasification","volume":"110","author":"Sadooghi","year":"2013","journal-title":"Fuel Process. Technol."},{"key":"ref_88","doi-asserted-by":"crossref","first-page":"513","DOI":"10.1016\/j.apcatb.2018.07.073","article-title":"Revealing the Pathways of Catalyst Deactivation by Coke during the Hydrodeoxygenation of Raw Bio-Oil","volume":"239","author":"Palos","year":"2018","journal-title":"Appl. Catal. B Environ."},{"key":"ref_89","doi-asserted-by":"crossref","first-page":"e10701","DOI":"10.1002\/wer.10701","article-title":"Pyrolysis and Gasification at Water Resource Recovery Facilities: Status of the Industry","volume":"94","author":"Winchell","year":"2022","journal-title":"Water Environ. Res."},{"key":"ref_90","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1016\/j.rser.2019.04.011","article-title":"Hydrothermal Carbonization for Energy-Efficient Processing of Sewage Sludge: A Review","volume":"108","author":"Wang","year":"2019","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_91","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.wasman.2019.05.027","article-title":"Hydrothermal Carbonization of Sewage Sludge: A Critical Analysis of Process Severity, Hydrochar Properties and Environmental Implications","volume":"93","author":"Tasca","year":"2019","journal-title":"Waste Manag."},{"key":"ref_92","doi-asserted-by":"crossref","first-page":"144802","DOI":"10.1016\/j.cej.2023.144802","article-title":"Valorization of the Aqueous Phase from Hydrothermal Carbonization of Different Feedstocks: Challenges and Perspectives","volume":"472","author":"Nguyen","year":"2023","journal-title":"Chem. Eng. J."},{"key":"ref_93","doi-asserted-by":"crossref","first-page":"117186","DOI":"10.1016\/j.watres.2021.117186","article-title":"Hydrochar Derived from Municipal Sludge through Hydrothermal Processing: A Critical Review on Its Formation, Characterization, and Valorization","volume":"199","author":"Liu","year":"2021","journal-title":"Water Res."},{"key":"ref_94","doi-asserted-by":"crossref","first-page":"9093","DOI":"10.1021\/acssuschemeng.1c02638","article-title":"Effect of Prestage Hydrothermal Treatment on the Formation of Struvite vs Vivianite during Semicontinuous Anaerobic Digestion of Sewage Sludge","volume":"9","author":"Wang","year":"2021","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_95","doi-asserted-by":"crossref","first-page":"100819","DOI":"10.1016\/j.pecs.2019.100819","article-title":"Valorization of Hydrothermal Liquefaction Aqueous Phase: Pathways towards Commercial Viability","volume":"77","author":"Watson","year":"2020","journal-title":"Prog. Energy Combust. Sci."},{"key":"ref_96","doi-asserted-by":"crossref","first-page":"109628","DOI":"10.1016\/j.jece.2023.109628","article-title":"Multi-Criteria Evaluation of Energy Recovery from Urban Wastewater Sludges by Anaerobic Digestion and Hydrothermal Liquefaction","volume":"11","author":"Abeyratne","year":"2023","journal-title":"J. Environ. Chem. Eng."},{"key":"ref_97","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0896-8446(03)00031-7","article-title":"Corrosion in High-Temperature and Supercritical Water and Aqueous Solutions: A Review","volume":"29","author":"Kritzer","year":"2004","journal-title":"J. Supercrit. Fluids"},{"key":"ref_98","doi-asserted-by":"crossref","first-page":"356","DOI":"10.1016\/j.supflu.2018.07.018","article-title":"Influence of Reaction Conditions on the Catalytic Activity of a Nickel during the Supercritical Water Gasification of Dewatered Sewage Sludge","volume":"140","author":"Wang","year":"2018","journal-title":"J. Supercrit. Fluids"},{"key":"ref_99","doi-asserted-by":"crossref","first-page":"1435","DOI":"10.1021\/ie8012456","article-title":"Catalytic Gasification of Glucose over Ni\/Activated Charcoal in Supercritical Water","volume":"48","author":"Lee","year":"2009","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_100","doi-asserted-by":"crossref","first-page":"502","DOI":"10.1021\/ie030475+","article-title":"Influence of the Heating Rate and the Type of Catalyst on the Formation of Key Intermediates and on the Generation of Gases during Hydropyrolysis of Glucose in Supercritical Water in a Batch Reactor","volume":"43","author":"Kruse","year":"2004","journal-title":"Ind. Eng. Chem. Res."}],"container-title":["Energies"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1073\/17\/10\/2417\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:44:09Z","timestamp":1760107449000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1073\/17\/10\/2417"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,5,17]]},"references-count":100,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2024,5]]}},"alternative-id":["en17102417"],"URL":"https:\/\/doi.org\/10.3390\/en17102417","relation":{},"ISSN":["1996-1073"],"issn-type":[{"value":"1996-1073","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,5,17]]}}}