{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T11:35:30Z","timestamp":1771500930006,"version":"3.50.1"},"reference-count":28,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2019,12,23]],"date-time":"2019-12-23T00:00:00Z","timestamp":1577059200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Energies"],"abstract":"<jats:p>Pyrolysis of anaerobically digested sludge can serve as an efficient biomass for biofuel production. Pyrolysis produces products like char, bio-oil, and combustible gases by thermochemical conversion process. It can be used for sludge treatment that decreases sludge disposal problems. Sludge produced from anaerobic co-digestion (microalgae, cow dung, and paper) waste has high carbon and hydrogen content. We investigated the candidacy of the anaerobic sludge having high heating value (HHV) of 20.53 MJ\/kg as a reliable biomass for biofuels production. The process of pyrolysis was optimized with different temperatures (400, 500, and 600 \u00b0C) to produce high quantity and improved quality of the products, mainly bio-oil, char, and gas. The results revealed that with the increase in pyrolysis temperature the quantity of char decreased (81% to 55%), bio-oil increased (3% to 7%), and gas increased (2% to 5%). The HHV of char (19.2 MJ\/kg), bio-oil (28.1 MJ\/kg), and gas (18.1 MJ\/kg) were predominantly affected by the amount of fixed carbon, hydrocarbons, and volatile substance, respectively. The study confirmed that the anaerobic sludge is a promising biomass for biofuel production and pyrolysis is an efficient method for its safe disposal.<\/jats:p>","DOI":"10.3390\/en13010079","type":"journal-article","created":{"date-parts":[[2019,12,23]],"date-time":"2019-12-23T03:15:01Z","timestamp":1577070901000},"page":"79","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":19,"title":["Influence of Pyrolysis Temperature on Product Distribution and Characteristics of Anaerobic Sludge"],"prefix":"10.3390","volume":"13","author":[{"given":"Muhammad Usman","family":"Hanif","sequence":"first","affiliation":[{"name":"Institute of Environmental Science and Engineering, School of Civil and Environmental Engineering, National University of Sciences and Technology, Sector H-12, Islamabad 44000, Pakistan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mohammed","family":"Zwawi","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, King Abdul Aziz University, Rabigh 21911, Saudi Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sergio C.","family":"Capareda","sequence":"additional","affiliation":[{"name":"Bio-Energy Testing and Analysis Laboratory (BETA Lab), Biological and Agricultural Engineering Department, Texas A&amp;M University, College Station, TX 77843, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hamid","family":"Iqbal","sequence":"additional","affiliation":[{"name":"Rawalpindi Waste Management Company, A-81, Iran Road, Satellite Town, Rawalpindi 46000, Pakistan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2439-1611","authenticated-orcid":false,"given":"Mohammed","family":"Algarni","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, King Abdul Aziz University, Rabigh 21911, Saudi Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bassem F.","family":"Felemban","sequence":"additional","affiliation":[{"name":"Mechanical Engineering Department, Taif University, Taif 21974, Saudia Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4861-635X","authenticated-orcid":false,"given":"Ali","family":"Bahadar","sequence":"additional","affiliation":[{"name":"Department of Chemical and Materials Engineering, King Abdul Aziz University, Rabigh 21911, Saudi Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9427-0607","authenticated-orcid":false,"given":"Adeel","family":"Waqas","sequence":"additional","affiliation":[{"name":"Center for Advanced Studies in Energy, National University of Sciences and Technology, Islamabad 44000, Pakistan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,12,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1065\/espr2006.12.365","article-title":"Organic Contaminants from Sewage Sludge Applied to Agricultural Soils","volume":"14","author":"Laturnus","year":"2007","journal-title":"Environ. Sci. Pollut. Res."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1016\/j.wasman.2018.05.034","article-title":"High temperature pyrolysis of sewage sludge as a sustainable process for energy recovery","volume":"78","author":"Karaca","year":"2019","journal-title":"Waste Manag."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1233","DOI":"10.1016\/j.watres.2006.01.023","article-title":"Characterization of extracellular polymeric substances of aerobic and anaerobic sludge using three-dimensional excitation and emission matrix fluorescence spectroscopy","volume":"40","author":"Sheng","year":"2006","journal-title":"Water Res."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.biortech.2017.02.130","article-title":"Removal of antimony (iii) and cadmium (ii) from aqueous solution using animal manure-derived hydrochars and pyrochars","volume":"234","author":"Han","year":"2017","journal-title":"Bioresour. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/S0960-8524(01)00118-3","article-title":"Energy production from biomass (part 1): Overview of biomass","volume":"83","author":"McKendry","year":"2002","journal-title":"Bioresour. Technol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1126","DOI":"10.1016\/j.rser.2015.12.185","article-title":"Lignocellulosic biomass pyrolysis: A review of product properties and effects of pyrolysis parameters","volume":"57","author":"Kan","year":"2016","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1205\/095758202753553220","article-title":"An evaluation of an autothermal aerobic digestion system","volume":"80","author":"Riley","year":"2002","journal-title":"Process Saf. Environ. Prot."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2273","DOI":"10.1016\/j.fuel.2011.02.037","article-title":"Methylation of wood fatty and resin acids for production of biodiesel","volume":"90","author":"Demirbas","year":"2011","journal-title":"Fuel"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1016\/j.fuproc.2012.04.023","article-title":"Characterisation of the properties of alternative fuels containing sewage sludge","volume":"104","author":"Wzorek","year":"2012","journal-title":"Fuel Process. Technol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1043","DOI":"10.1016\/j.chemosphere.2017.06.029","article-title":"Sustainable pyrolytic sludge-char preparation on improvement of closed-loop sewage sludge treatment: Characterization and combined in-situ application","volume":"184","author":"Jin","year":"2017","journal-title":"Chemosphere"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2495","DOI":"10.1007\/s11356-017-0271-0","article-title":"Changes of chromium speciation and organic matter during low-temperature pyrolysis of tannery sludge","volume":"25","author":"Zhou","year":"2018","journal-title":"Environ. Sci. Pollut. Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.jechem.2015.11.005","article-title":"Biomass gasification technology: The state of the art overview","volume":"25","author":"Molino","year":"2016","journal-title":"J. Energy Chem."},{"key":"ref_13","first-page":"337","article-title":"Steam gasification of refuse-derived fuel in a rotary kiln pilot plant: Experimental tests","volume":"32","author":"Molino","year":"2013","journal-title":"Chem. Eng. Trans."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"182","DOI":"10.1016\/j.cattod.2016.04.005","article-title":"Experimental investigations of hydrogen production from CO catalytic conversion of tar rich syngas by biomass gasification","volume":"277","author":"Chianese","year":"2016","journal-title":"Catal. Today"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.apcatb.2018.06.068","article-title":"New concept for old reaction: Novel WGS catalyst design","volume":"238","author":"Ivanova","year":"2018","journal-title":"Appl. Catal. B Environ."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"101601","DOI":"10.1016\/j.algal.2019.101601","article-title":"Gasification of lipid-extracted microalgae biomass promoted by waste eggshell as CaO catalyst","volume":"42","author":"Raheem","year":"2019","journal-title":"Algal Res."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"764","DOI":"10.1016\/j.enconman.2013.08.033","article-title":"Evaluating the effects of temperature on pressurized pyrolysis of Nannochloropsis oculata based on products yields and characteristics","volume":"76","author":"Maguyon","year":"2013","journal-title":"Energy Convers. Manag."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1016\/j.jaap.2017.11.019","article-title":"Operating parameters for bio-oil production in biomass pyrolysis: A review","volume":"129","author":"Guedes","year":"2018","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"881","DOI":"10.1080\/03650340.2017.1407870","article-title":"Influence of pyrolysis temperature on chemical and physical properties of biochar from sewage sludge","volume":"64","author":"Figueiredo","year":"2018","journal-title":"Arch. Agron. Soil Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"3261","DOI":"10.1016\/S0043-1354(02)00017-9","article-title":"Microwave-induced pyrolysis of sewage sludge","volume":"36","author":"Menndez","year":"2002","journal-title":"Water Res."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"487","DOI":"10.1016\/j.fuel.2004.10.010","article-title":"A correlation for calculating HHV from proximate analysis of solid fuels","volume":"84","author":"Parikh","year":"2005","journal-title":"Fuel"},{"key":"ref_22","unstructured":"Monnet, F. (2003). An introduction to anaerobic digestion of organic wastes. Remade Scotland; Final Report Biogasmax."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"848","DOI":"10.1021\/ef0502397","article-title":"Pyrolysis of Wood\/Biomass for Bio-oil: A Critical Review","volume":"20","author":"Mohan","year":"2006","journal-title":"Energy Fuels"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1016\/S0961-9534(00)00064-7","article-title":"Characterization of the pyrolysis oil produced in the slow pyrolysis of sunflower-extracted bagasse","volume":"20","author":"Yorgun","year":"2001","journal-title":"Biomass Bioenergy"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"274","DOI":"10.1016\/j.biortech.2011.12.125","article-title":"Production of phenols and biofuels by catalytic microwave pyrolysis of lignocellulosic biomass","volume":"108","author":"Bu","year":"2012","journal-title":"Bioresour. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"4593","DOI":"10.1016\/j.biortech.2010.01.070","article-title":"The direct pyrolysis and catalytic pyrolysis of Nannochloropsis sp. residue for renewable bio-oils","volume":"101","author":"Pan","year":"2010","journal-title":"Bioresour. Technol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1007\/s11244-008-9062-7","article-title":"Production of hydrogen and syngas via steam gasification of glycerol in a fixed-bed reactor","volume":"49","author":"Valliyappan","year":"2008","journal-title":"Top. Catal."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"803","DOI":"10.1016\/j.renene.2005.03.013","article-title":"Effect of heating rate on the pyrolysis yields of rapeseed","volume":"31","author":"Yaman","year":"2006","journal-title":"Renew. Energy"}],"container-title":["Energies"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1073\/13\/1\/79\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:44:48Z","timestamp":1760190288000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1073\/13\/1\/79"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,12,23]]},"references-count":28,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2020,1]]}},"alternative-id":["en13010079"],"URL":"https:\/\/doi.org\/10.3390\/en13010079","relation":{},"ISSN":["1996-1073"],"issn-type":[{"value":"1996-1073","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,12,23]]}}}