Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
Environmental Chemistry Environmental Chemistry Society
Environmental problems - Chemical approaches
RESEARCH ARTICLE (Open Access)

Thermochemical conversion characteristics of biosolid samples from a wastewater treatment plant in Brisbane, Australia

San Shwe Hla A , Nuttaphol Sujarittam A and Alexander Ilyushechkin https://orcid.org/0000-0002-5978-3914 A *
+ Author Affiliations
- Author Affiliations

A CSIRO Energy, PO Box 883, Kenmore 4069, Australia.

* Correspondence to: alex.ilyushechkin@csiro.au

Handling Editor: Ke Sun

Environmental Chemistry 19(6) 385-399 https://doi.org/10.1071/EN22074
Submitted: 7 July 2022  Accepted: 5 November 2022   Published: 18 January 2023

© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Environmental context. Biosolids are nutrient-rich organic materials. They can be used as fertiliser and solid amendments in agriculture if treated according to regulatory requirements. If farming applications of biosolids decline due to potential pollution from their heavy metal content, an alternative to traditional methods of biosolid disposal is required. In this context, thermal processing of biosolids is an economically and environmentally suitable option to convert large quantities of biosolids into useful energy.

Rationale. Due to more stringent environmental regulations and frequently required long-distance transportation, the traditional disposal of biosolids from wastewater treatment plants in landfills and farms is becoming unsustainable. A potentially economical and environmental option is the thermochemical conversion of biosolids into energy and value-added products. This paper describes the chemical composition and energy content of a representative biosolid sample collected from a major wastewater-treatment plant in Queensland, Australia.

Methodology. The thermochemical behaviour and compositional changes in biosolids were investigated under a wide range of pyrolysis and gasification conditions using a horizontal tube furnace (HTF), a fixed-bed reactor and a thermogravimetric analyser (TGA). In terms of practical application of by-products, we describe mineral matter transformations in char and ashes during pyrolysis and volatilisation as well as under different gasification conditions.

Results. HTF experiments revealed that at pyrolysis below 800°C, mainly organic species were released, while losses of inorganic elements (phosphorus, magnesium and zinc) occurred at higher temperatures. In-situ gasification behaviour of biosolid chars in the TGA reactor showed that the gasification reaction of biosolid chars occurred rapidly at temperatures above 720°C, regardless of the pyrolysis temperatures at which those chars were produced. Mineral matter transformations began at temperatures above 600°C, and mainly involved the transformation of amorphous phases into crystalline oxide and phosphide forms. Under gasification conditions, all crystalline phases appeared as different phosphates and alumino-silicates.

Discussion. The methods described here provide different options for the disposal of biosolids from wastewater by adjusting and optimising thermochemical conversion processes.

Keywords: ash characteristics, biosolids, gasification,  mineral matter, phase transformation, pyrolysis, sewage sludge, thermochemical conversion.


References

Agrafioti E, Bouras G, Kalderis D, Diamadopoulos E (2013). Biochar production by sewage sludge pyrolysis. Journal of Analytical and Applied Pyrolysis 101, 72–78.
Biochar production by sewage sludge pyrolysis.Crossref | GoogleScholarGoogle Scholar |

ANZBP (2017) Australian Biosolids Statistics: Biosolids production in Australia - 2017. Available at https://www.biosolids.com.au/guidelines/australian-biosolids-statistics/ [verified on 9 December 2022]

Arjharn W, Hinsui T, Liplap P, Raghavan GSV (2013). Evaluation of an Energy Production System from Sewage Sludge Using a Pilot-Scale Downdraft Gasifier. Energy & Fuels 27, 229–236.
Evaluation of an Energy Production System from Sewage Sludge Using a Pilot-Scale Downdraft Gasifier.Crossref | GoogleScholarGoogle Scholar |

Atienza-Martínez M, Fonts I, Ábrego J, Ceamanos J, Gea G (2013). Sewage sludge torrefaction in a fluidized bed reactor. Chemical Engineering Journal 222, 534–545.
Sewage sludge torrefaction in a fluidized bed reactor.Crossref | GoogleScholarGoogle Scholar |

Bläsing M, Müller M (2013). Release of alkali metal, sulphur, and chlorine species from high temperature gasification of high- and low-rank coals. Fuel Processing Technology 106, 289–294.
Release of alkali metal, sulphur, and chlorine species from high temperature gasification of high- and low-rank coals.Crossref | GoogleScholarGoogle Scholar |

Boström D, Skoglund N, Grimm A, Boman C, Öhman M, Broström M, Backman R (2012). Ash Transformation Chemistry during Combustion of Biomass. Energy & Fuels 26, 85–93.
Ash Transformation Chemistry during Combustion of Biomass.Crossref | GoogleScholarGoogle Scholar |

BSI (2010) BS EN 14775:2009 − Solid biofuels. Determination of ash content. The BritishStandards Institution.
| Crossref |

Calvo LF, García AI, Otero M (2013). An Experimental Investigation of Sewage Sludge Gasification in a Fluidized Bed Reactor. The Scientific World Journal 2013, 479403
An Experimental Investigation of Sewage Sludge Gasification in a Fluidized Bed Reactor.Crossref | GoogleScholarGoogle Scholar |

Cartmell E, Gostelow P, Riddell-Black D, Simms N, Oakey J, Morris J, Jeffrey P, Howsam P, Pollard SJ (2006). Biosolids—A Fuel or a Waste? An Integrated Appraisal of Five Co-combustion Scenarios with Policy Analysis. Environmental Science & Technology 40, 649–658.
Biosolids—A Fuel or a Waste? An Integrated Appraisal of Five Co-combustion Scenarios with Policy Analysis.Crossref | GoogleScholarGoogle Scholar |

Chen Y, Guo L, Jin H, Yin J, Lu Y, Zhang X (2013). An experimental investigation of sewage sludge gasification in near and super-critical water using a batch reactor. International Journal of Hydrogen Energy 38, 12912–12920.
An experimental investigation of sewage sludge gasification in near and super-critical water using a batch reactor.Crossref | GoogleScholarGoogle Scholar |

Chun YN, Ji DW, Yoshikawa K (2013). Pyrolysis and gasification characterization of sewage sludge for high quality gas and char production. Journal of Mechanical Science and Technology 27, 263–272.
Pyrolysis and gasification characterization of sewage sludge for high quality gas and char production.Crossref | GoogleScholarGoogle Scholar |

Cieślik BM, Namieśnik J, Konieczka P (2015). Review of sewage sludge management: standards, regulations and analytical methods. Journal of Cleaner Production 90, 1–15.
Review of sewage sludge management: standards, regulations and analytical methods.Crossref | GoogleScholarGoogle Scholar |

Cui H, Ninomiya Y, Masui M, Mizukoshi H, Sakano T, Kanaoka C (2006). Fundamental Behaviors in Combustion of Raw Sewage Sludge. Energy & Fuels 20, 77–83.
Fundamental Behaviors in Combustion of Raw Sewage Sludge.Crossref | GoogleScholarGoogle Scholar |

Darvodelsky P (2011) Biosolids snapshot. The Department of Sustainability, Environment, Water, Population and Communities. Australia. https://www.agriculture.gov.au/sites/default/files/documents/biosolids-snapshot.pdf/ [verified on 9 December 2022]

de Andrés JM, Narros A, Rodríguez ME (2011a). Air-steam gasification of sewage sludge in a bubbling bed reactor: Effect of alumina as a primary catalyst. Fuel Processing Technology 92, 433–440.
Air-steam gasification of sewage sludge in a bubbling bed reactor: Effect of alumina as a primary catalyst.Crossref | GoogleScholarGoogle Scholar |

de Andrés JM, Narros A, Rodríguez ME (2011b). Behaviour of dolomite, olivine and alumina as primary catalysts in air–steam gasification of sewage sludge. Fuel 90, 521–527.
Behaviour of dolomite, olivine and alumina as primary catalysts in air–steam gasification of sewage sludge.Crossref | GoogleScholarGoogle Scholar |

Dogru M, Midilli A, Howarth CR (2002). Gasification of sewage sludge using a throated downdraft gasifier and uncertainty analysis. Fuel Processing Technology 75, 55–82.
Gasification of sewage sludge using a throated downdraft gasifier and uncertainty analysis.Crossref | GoogleScholarGoogle Scholar |

Donatello S, Cheeseman CR (2013). Recycling and recovery routes for incinerated sewage sludge ash (ISSA): a review. Waste Management 33, 2328–2340.
Recycling and recovery routes for incinerated sewage sludge ash (ISSA): a review.Crossref | GoogleScholarGoogle Scholar |

Dubinin MM (1966) Porous structure and adsorption properties of active carbons. In ‘Chemistry and Physics of Carbon. Vol. 2’. (Ed. PJ Walker Jr) pp. 51–120. (Marcel Dekker: New York)

Fairous S, Rusnah S, Maryam H (2010) Potential source of bio-fuel from pyrolysis of treated sewage sludge. In ‘2010 International Conference on Science and Social Research (CSSR 2010)’, 5–7 December 2010, Kuala Lumpur, Malaysia. pp. 1272–1277 (IEEE)
| Crossref |

Fan H, Zhou H, Wang J (2014). Pyrolysis of municipal sewage sludges in a slowly heating and gas sweeping fixed-bed reactor. Energy Conversion and Management 88, 1151–1158.
Pyrolysis of municipal sewage sludges in a slowly heating and gas sweeping fixed-bed reactor.Crossref | GoogleScholarGoogle Scholar |

Fenwick G (2016) Achiving the biosolids strategy at Sandgate Sewage Treatment Plant. In ‘79th Annual WIOA Victorian Water Industry Operations Conference and Exhibition’. 31 August–1 September 2016, Bendigo, VIC, Australia. (Water Industry Operators Association of Australia (WIOA)). Available at http://www.wioa.org.au/conference_papers/2016_vic/documents/Gary_Fenwick.pdf

Fonts I, Juan A, Gea G, Murillo MB, Sánchez JL (2008). Sewage Sludge Pyrolysis in Fluidized Bed, 1: Influence of Operational Conditions on the Product Distribution. Industrial & Engineering Chemistry Research 47, 5376–5385.
Sewage Sludge Pyrolysis in Fluidized Bed, 1: Influence of Operational Conditions on the Product Distribution.Crossref | GoogleScholarGoogle Scholar |

Fuentes-Cano D, Gómez-Barea A, Nilsson S, Ollero P (2013). The influence of temperature and steam on the yields of tar and light hydrocarbon compounds during devolatilization of dried sewage sludge in a fluidized bed. Fuel 108, 341–350.
The influence of temperature and steam on the yields of tar and light hydrocarbon compounds during devolatilization of dried sewage sludge in a fluidized bed.Crossref | GoogleScholarGoogle Scholar |

Fytili D, Zabaniotou A (2008). Utilization of sewage sludge in EU application of old and new methods—A review. Renewable and Sustainable Energy Reviews 12, 116–140.
Utilization of sewage sludge in EU application of old and new methods—A review.Crossref | GoogleScholarGoogle Scholar |

Gikas P (2017). Ultra high temperature gasification of municipal wastewater primary biosolids in a rotary kiln reactor for the production of synthesis gas. Journal of Environmental Management 203, 688–694.
Ultra high temperature gasification of municipal wastewater primary biosolids in a rotary kiln reactor for the production of synthesis gas.Crossref | GoogleScholarGoogle Scholar |

Gil-Lalaguna N, Sánchez JL, Murillo MB, Rodríguez E, Gea G (2014). Air–steam gasification of sewage sludge in a fluidized bed. Influence of some operating conditions. Chemical Engineering Journal 248, 373–382.
Air–steam gasification of sewage sludge in a fluidized bed. Influence of some operating conditions.Crossref | GoogleScholarGoogle Scholar |

Gomez-Barea A, Nilsson S, Vidal Barrero F, Campoy M (2010). Devolatilization of wood and wastes in fluidized bed. Fuel Processing Technology 91, 1624–1633.
Devolatilization of wood and wastes in fluidized bed.Crossref | GoogleScholarGoogle Scholar |

Gong M, Zhu W, Fan Y, Zhang H, Su Y (2016). Influence of the reactant carbon–hydrogen–oxygen composition on the key products of the direct gasification of dewatered sewage sludge in supercritical water. Bioresource Technology 208, 81–86.
Influence of the reactant carbon–hydrogen–oxygen composition on the key products of the direct gasification of dewatered sewage sludge in supercritical water.Crossref | GoogleScholarGoogle Scholar |

Gonzaga MIS, Mackowiak CL, Comerford NB, Moline EFdV, Shirley JP, Guimaraes DV (2017). Pyrolysis methods impact biosolids-derived biochar composition, maize growth and nutrition. Soil and Tillage Research 165, 59–65.
Pyrolysis methods impact biosolids-derived biochar composition, maize growth and nutrition.Crossref | GoogleScholarGoogle Scholar |

Good J, Ventress L, Knoef H, Zielke U, Hansen PL, Kamp WVD, Wild PD, Coda B, Paasen SV, Kiel J, Sjöström K, Liliedahl T, Unger C, Neeft J, Suomalainen M, Simell P (2005) Sampling and analysis of tar and particles in biomass producer gases, Technical Report prepared under CEN BT/TF 143 “Organic contaminants (“tar”) in biomass producer gases”. Available at http://www.eeci.net/results/pdf/Technical-Report-version-3_8-final.pdf [verified May 2018]

Hannl TK, Häggström G, Hedayati A, Skoglund N, Kuba M, Öhman M (2022). Ash transformation during single-pellet gasification of sewage sludge and mixtures with agricultural residues with a focus on phosphorus. Fuel Processing Technology 227, 107102
Ash transformation during single-pellet gasification of sewage sludge and mixtures with agricultural residues with a focus on phosphorus.Crossref | GoogleScholarGoogle Scholar |

Hedayati A, Lindgren R, Skoglund N, Boman C, Kienzl N, Öhman M (2021). Ash Transformation during Single-Pellet Combustion of Agricultural Biomass with a Focus on Potassium and Phosphorus. Energy & Fuels 35, 1449–1464.
Ash Transformation during Single-Pellet Combustion of Agricultural Biomass with a Focus on Potassium and Phosphorus.Crossref | GoogleScholarGoogle Scholar |

Herzel H, Krüger O, Hermann L, Adam C (2016). Sewage sludge ash — A promising secondary phosphorus source for fertilizer production. Science of the Total Environment 542, 1136–1143.
Sewage sludge ash — A promising secondary phosphorus source for fertilizer production.Crossref | GoogleScholarGoogle Scholar |

Hla SS, Roberts D (2015). Characterisation of chemical composition and energy content of green waste and municipal solid waste from Greater Brisbane, Australia. Waste Management 41, 12–19.
Characterisation of chemical composition and energy content of green waste and municipal solid waste from Greater Brisbane, Australia.Crossref | GoogleScholarGoogle Scholar |

Hla SS, Lopes R, Roberts D (2016). The CO2 gasification reactivity of chars produced from Australian municipal solid waste. Fuel 185, 847–854.
The CO2 gasification reactivity of chars produced from Australian municipal solid waste.Crossref | GoogleScholarGoogle Scholar |

Hla SS, Ilyushechkin A, Ord L, Roberts D (2020) Database of chemical properties of Australian biomass and waste, v13, CSIRO Data Collection. Available at https://sc-63-cdc.it.csiro.au/content/19/ [verified December 2020]

Hodge EM (2009) The coal char–COreaction at high temperature and high pressure. PhD thesis, School of Chemical Engineering and Industrial Chemistry, University of New South Wales, Sydney, Australia.

Hwang IH, Ouchi Y, Matsuto T (2007). Characteristics of leachate from pyrolysis residue of sewage sludge. Chemosphere 68, 1913–1919.
Characteristics of leachate from pyrolysis residue of sewage sludge.Crossref | GoogleScholarGoogle Scholar |

Inguanzo M, Menéndez JA, Fuente E, Pis JJ (2001). Reactivity of pyrolyzed sewage sludge in air and CO2. Journal of Analytical and Applied Pyrolysis 58–59, 943–954.
Reactivity of pyrolyzed sewage sludge in air and CO2.Crossref | GoogleScholarGoogle Scholar |

ISO (2015) ISO 18134-3:2015 Solid biofuels — Determination of moisture content —Oven dry method — Part 3: Moisture in general analysis sample, https://www.iso.org/standard/61637.html/ [verified on 9 December 2022]

Jaramillo-Arango A, Fonts I, Chejne F, Arauzo J (2016). Product compositions from sewage sludge pyrolysis in a fluidized bed and correlations with temperature. Journal of Analytical and Applied Pyrolysis 121, 287–296.
Product compositions from sewage sludge pyrolysis in a fluidized bed and correlations with temperature.Crossref | GoogleScholarGoogle Scholar |

Jayaraman K, Gökalp I (2015). Pyrolysis, combustion and gasification characteristics of miscanthus and sewage sludge. Energy Conversion and Management 89, 83–91.
Pyrolysis, combustion and gasification characteristics of miscanthus and sewage sludge.Crossref | GoogleScholarGoogle Scholar |

Jensen PA, Frandsen FJ, Dam-Johansen K, Sander B (2000). Experimental Investigation of the Transformation and Release to Gas Phase of Potassium and Chlorine during Straw Pyrolysis. Energy & Fuels 14, 1280–1285.
Experimental Investigation of the Transformation and Release to Gas Phase of Potassium and Chlorine during Straw Pyrolysis.Crossref | GoogleScholarGoogle Scholar |

Jin J, Li Y, Zhang J, Wu S, Cao Y, Liang P, Zhang J, Wong MH, Wang M, Shan S, Christie P (2016). Influence of pyrolysis temperature on properties and environmental safety of heavy metals in biochars derived from municipal sewage sludge. Journal of Hazardous Materials 320, 417–426.
Influence of pyrolysis temperature on properties and environmental safety of heavy metals in biochars derived from municipal sewage sludge.Crossref | GoogleScholarGoogle Scholar |

Kirkels AF, Verbong GPJ (2011). Biomass gasification: Still promising? A 30-year global overview. Renewable and Sustainable Energy Reviews 15, 471–481.
Biomass gasification: Still promising? A 30-year global overview.Crossref | GoogleScholarGoogle Scholar |

Li QH, Zhang YG, Meng AH, Li L, Li GX (2013). Study on ash fusion temperature using original and simulated biomass ashes. Fuel Processing Technology 107, 107–112.
Study on ash fusion temperature using original and simulated biomass ashes.Crossref | GoogleScholarGoogle Scholar |

Li M, Tang Y, Lu XY, Zhang Z, Cao Y (2018). Phosphorus speciation in sewage sludge and the sludge-derived biochar by a combination of experimental methods and theoretical simulation. Water Research 140, 90–99.
Phosphorus speciation in sewage sludge and the sludge-derived biochar by a combination of experimental methods and theoretical simulation.Crossref | GoogleScholarGoogle Scholar |

Liu H, Wang Y, Hu H, Fu B, Yao H, Wendt JOL (2020). Enrichment mechanism of arsenic in fine ash deposits during co-combustion of rice husk and coal. Fuel 281, 118712
Enrichment mechanism of arsenic in fine ash deposits during co-combustion of rice husk and coal.Crossref | GoogleScholarGoogle Scholar |

Lu T, Yuan H, Wang Y, Huang H, Chen Y (2015). Characteristic of heavy metals in biochar derived from sewage sludge. Journal of Material Cycles and Waste Management 18, 725–733.
Characteristic of heavy metals in biochar derived from sewage sludge.Crossref | GoogleScholarGoogle Scholar |

Lundin M, Olofsson M, Pettersson GJ, Zetterlund H (2004). Environmental and economic assessment of sewage sludge handling options. Resources, Conservation and Recycling 41, 255–278.
Environmental and economic assessment of sewage sludge handling options.Crossref | GoogleScholarGoogle Scholar |

Midilli A, Dogru M, Howarth CR, Ling MJ, Ayhan T (2001). Combustible gas production from sewage sludge with a downdraft gasifier. Energy Conversion and Management 42, 157–172.
Combustible gas production from sewage sludge with a downdraft gasifier.Crossref | GoogleScholarGoogle Scholar |

Moon J, Mun T-Y, Yang W, Lee U, Hwang J, Jang E, Choi C (2015). Effects of hydrothermal treatment of sewage sludge on pyrolysis and steam gasification. Energy Conversion and Management 103, 401–407.
Effects of hydrothermal treatment of sewage sludge on pyrolysis and steam gasification.Crossref | GoogleScholarGoogle Scholar |

Nidheesh PV, Gopinath A, Ranjith N, Praveen Akre A, Sreedharan V, Suresh Kumar M (2021). Potential role of biochar in advanced oxidation processes: A sustainable approach. Chemical Engineering Journal 405, 126582
Potential role of biochar in advanced oxidation processes: A sustainable approach.Crossref | GoogleScholarGoogle Scholar |

Nilsson S, Gómez-Barea A, Cano DF (2012). Gasification reactivity of char from dried sewage sludge in a fluidized bed. Fuel 92, 346–353.
Gasification reactivity of char from dried sewage sludge in a fluidized bed.Crossref | GoogleScholarGoogle Scholar |

Nilsson S, Gómez-Barea A, Ollero P (2013). Gasification of char from dried sewage sludge in fluidized bed: Reaction rate in mixtures of CO2 and H2O. Fuel 105, 764–768.
Gasification of char from dried sewage sludge in fluidized bed: Reaction rate in mixtures of CO2 and H2O.Crossref | GoogleScholarGoogle Scholar |

Nowicki L, Antecka A, Bedyk T, Stolarek P, Ledakowicz S (2011). The kinetics of gasification of char derived from sewage sludge. Journal of Thermal Analysis and Calorimetry 104, 693–700.
The kinetics of gasification of char derived from sewage sludge.Crossref | GoogleScholarGoogle Scholar |

Park HJ, Heo HS, Park Y-K, Yim J-H, Jeon J-K, Park J, Ryu C, Kim S-S (2010). Clean bio-oil production from fast pyrolysis of sewage sludge: Effects of reaction conditions and metal oxide catalysts. Bioresource Technology 101, S83–S85.
Clean bio-oil production from fast pyrolysis of sewage sludge: Effects of reaction conditions and metal oxide catalysts.Crossref | GoogleScholarGoogle Scholar |

Quispe I, Navia R, Kahhat R (2017). Energy potential from rice husk through direct combustion and fast pyrolysis: A review. Waste Management 59, 200–210.
Energy potential from rice husk through direct combustion and fast pyrolysis: A review.Crossref | GoogleScholarGoogle Scholar |

Raheem A, Sikarwar VS, He J, Dastyar W, Dionysiou DD, Wang W, Zhao M (2018). Opportunities and challenges in sustainable treatment and resource reuse of sewage sludge: A review. Chemical Engineering Journal 337, 616–641.
Opportunities and challenges in sustainable treatment and resource reuse of sewage sludge: A review.Crossref | GoogleScholarGoogle Scholar |

Roberts DG, Harris DJ (2000). Char Gasification with O2, CO2 and H2O: Effects of Pressure on Intrinsic Reaction Kinetics. Energy & Fuels 14, 483–489.
Char Gasification with O2, CO2 and H2O: Effects of Pressure on Intrinsic Reaction Kinetics.Crossref | GoogleScholarGoogle Scholar |

Roy MM, Dutta A, Corscadden K, Havard P, Dickie L (2011). Review of biosolids management options and co-incineration of a biosolid-derived fuel. Waste Management 31, 2228–2235.
Review of biosolids management options and co-incineration of a biosolid-derived fuel.Crossref | GoogleScholarGoogle Scholar |

Rulkens WH, Bien JD (2004). Recovery of energy from sludge – Comparison of the various options. Water Science and Technology 50, 213–221.
Recovery of energy from sludge – Comparison of the various options.Crossref | GoogleScholarGoogle Scholar |

Sattar A, Leeke GA, Hornung A, Wood J (2014). Steam gasification of rapeseed, wood, sewage sludge and miscanthus biochars for the production of a hydrogen-rich syngas. Biomass and Bioenergy 69, 276–286.
Steam gasification of rapeseed, wood, sewage sludge and miscanthus biochars for the production of a hydrogen-rich syngas.Crossref | GoogleScholarGoogle Scholar |

Saveyn H, Ferrasse JH, Hernandez AB, Rose J, Meeren PVd, Roche N (2011). The Distribution of Heavy Metals Following Sewage Sludge Gasification. Journal of Residuals Science and Technology 8, 61–66.

Saw W, McKinnon H, Gilmour I, Pang S (2012). Production of hydrogen-rich syngas from steam gasification of blend of biosolids and wood using a dual fluidised bed gasifier. Fuel 93, 473–478.
Production of hydrogen-rich syngas from steam gasification of blend of biosolids and wood using a dual fluidised bed gasifier.Crossref | GoogleScholarGoogle Scholar |

Scott SA, Davidson JF, Dennis JS, Fennell PS, Hayhurst AN (2005). The rate of gasification by CO2 of chars from waste. Proceedings of the Combustion Institute 30, 2151–2159.
The rate of gasification by CO2 of chars from waste.Crossref | GoogleScholarGoogle Scholar |

Seredych M, Bandosz TJ (2007). Sewage sludge as a single precursor for development of composite adsorbents/catalysts. Chemical Engineering Journal 128, 59–67.
Sewage sludge as a single precursor for development of composite adsorbents/catalysts.Crossref | GoogleScholarGoogle Scholar |

Shao J, Yan R, Chen H, Wang B, Lee DH, Liang DT (2008). Pyrolysis Characteristics and Kinetics of Sewage Sludge by Thermogravimetry Fourier Transform Infrared Analysis. Energy & Fuels 22, 38–45.
Pyrolysis Characteristics and Kinetics of Sewage Sludge by Thermogravimetry Fourier Transform Infrared Analysis.Crossref | GoogleScholarGoogle Scholar |

Shao Y, Tan H, Shen D, Zhou Y, Jin Z, Zhou D, Lu W, Long Y (2020). Synthesis of improved hydrochar by microwave hydrothermal carbonization of green waste. Fuel 266, 117146
Synthesis of improved hydrochar by microwave hydrothermal carbonization of green waste.Crossref | GoogleScholarGoogle Scholar |

Singh RP, Agrawal M (2008). Potential benefits and risks of land application of sewage sludge. Waste Management 28, 347–358.
Potential benefits and risks of land application of sewage sludge.Crossref | GoogleScholarGoogle Scholar |

Skoglund N, Bäfver L, Fahlström J, Holmén E, Renström C (2016). Fuel design in co-combustion of demolition wood chips and municipal sewage sludge. Fuel Processing Technology 141, 196–201.
Fuel design in co-combustion of demolition wood chips and municipal sewage sludge.Crossref | GoogleScholarGoogle Scholar |

Song W, Guo M (2012). Quality variations of poultry litter biochar generated at different pyrolysis temperatures. Journal of Analytical and Applied Pyrolysis 94, 138–145.
Quality variations of poultry litter biochar generated at different pyrolysis temperatures.Crossref | GoogleScholarGoogle Scholar |

Spanos T, Ene A, Styliani Patronidou C, Xatzixristou C (2016). Temporal variability of sewage sludge heavy metal content from Greek wastewater treatment plants. Ecological Chemistry and Engineering S 23, 271–283.
Temporal variability of sewage sludge heavy metal content from Greek wastewater treatment plants.Crossref | GoogleScholarGoogle Scholar |

Stylianou M, Christou A, Dalias P, Polycarpou P, Michael C, Agapiou A, Papanastasiou P, Fatta-Kassinos D (2020). Physicochemical and structural characterization of biochar derived from the pyrolysis of biosolids, cattle manure and spent coffee grounds. Journal of the Energy Institute 93, 2063–2073.
Physicochemical and structural characterization of biochar derived from the pyrolysis of biosolids, cattle manure and spent coffee grounds.Crossref | GoogleScholarGoogle Scholar |

Syed-Hassan SSA, Wang Y, Hu S, Su S, Xiang J (2017). Thermochemical processing of sewage sludge to energy and fuel: Fundamentals, challenges and considerations. Renewable and Sustainable Energy Reviews 80, 888–913.
Thermochemical processing of sewage sludge to energy and fuel: Fundamentals, challenges and considerations.Crossref | GoogleScholarGoogle Scholar |

Thy P, Jenkins B, Grundvig S, Shiraki R, Lesher C (2006). High temperature elemental losses and mineralogical changes in common biomass ashes. Fuel 85, 783–795.
High temperature elemental losses and mineralogical changes in common biomass ashes.Crossref | GoogleScholarGoogle Scholar |

Tippayawong N, Chaichana C, Promwungkwa A, Rerkkriangkrai P (2013). Investigation of a Small Biomass Gasifier–engine System Operation and Its Application to Water Pumping in Rural Thailand. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 35, 476–486.
Investigation of a Small Biomass Gasifier–engine System Operation and Its Application to Water Pumping in Rural Thailand.Crossref | GoogleScholarGoogle Scholar |

Tyagi VK, Lo S-L (2013). Sludge: A waste or renewable source for energy and resources recovery?. Renewable and Sustainable Energy Reviews 25, 708–728.
Sludge: A waste or renewable source for energy and resources recovery?.Crossref | GoogleScholarGoogle Scholar |

Tytła M, Widziewicz K, Zielewicz E (2016). Heavy metals and its chemical speciation in sewage sludge at different stages of processing. Environmental Technology 37, 899–908.
Heavy metals and its chemical speciation in sewage sludge at different stages of processing.Crossref | GoogleScholarGoogle Scholar |

Vassilev SV, Baxter D, Andersen LK, Vassileva CG, Morgan TJ (2012). An overview of the organic and inorganic phase composition of biomass. Fuel 94, 1–33.
An overview of the organic and inorganic phase composition of biomass.Crossref | GoogleScholarGoogle Scholar |

Werle S (2015). Gasification of a Dried Sewage Sludge in a Laboratory Scale Fixed Bed Reactor. Energy Procedia 66, 253–256.
Gasification of a Dried Sewage Sludge in a Laboratory Scale Fixed Bed Reactor.Crossref | GoogleScholarGoogle Scholar |

Werle S, Dudziak M (2014). Gaseous fuels production from dried sewage sludge via air gasification. Waste Management & Research 32, 601–607.
Gaseous fuels production from dried sewage sludge via air gasification.Crossref | GoogleScholarGoogle Scholar |

Xu M, Li D, Yan Y, Guo T, Pang H, Xue H (2017). Porous high specific surface area-activated carbon with co-doping N, S and P for high-performance supercapacitors. RSC Advances 7, 43780–43788.
Porous high specific surface area-activated carbon with co-doping N, S and P for high-performance supercapacitors.Crossref | GoogleScholarGoogle Scholar |

Zheng S, Yang Y, Li X, Liu H, Yan W, Sui R, Lu Q (2020). Temperature and emissivity measurements from combustion of pine wood, rice husk and fir wood using flame emission spectrum. Fuel Processing Technology 204, 106423
Temperature and emissivity measurements from combustion of pine wood, rice husk and fir wood using flame emission spectrum.Crossref | GoogleScholarGoogle Scholar |