Spent coffee ground is a massively produced coffee industry waste product whose reusage is beneficial. Proximate and ultimate and stochiometric analysis of torrefied spent coffee ground were performed and results were analyzed and compared with other research and materials. Spent coffee ground is a material with high content of carbon (above 50%) and therefore high calorific value (above 20 MJ·kg-1). Torrefaction improves the properties of the material, raising its calorific value up to 32 MJ·kg-1. Next, the phytotoxicity of the aqueous extract was tested using the cress test. The non-torrefied sample and the sample treated at 250 °C were the most toxic. The sample treated at 250 °C adversely affected the germination of the cress seeds due to residual caffeine, tannins and sulfur release. The sample treated at 350 °C performed best of all the tested samples. The sample treated at 350 °C can be applied to the soil as the germination index was higher than 50% and can be used as an alternative fuel with net calorific value comparable to fossil fuels.

Faculty of Agrobiology Food and Natural Resources Czech University of Life Sciences Prague Kamýcká 129 165 00 Prague Czech Republic

Faculty of Engineering Czech University of Life Sciences Prague Kamýcká 129 165 00 Prague Czech Republic

Zobrazit více v PubMed

International Coffee Organization-What’s New. [(accessed on 26 August 2022)]. Available online: https://www.ico.org/

International Coffee Organization-Trade Statistics Tables. [(accessed on 26 August 2022)]. Available online: https://www.ico.org/trade_statistics.asp?section=Statistics.

Rajesh Banu J., Yukesh Kannah R., Dinesh Kumar M., Preethi, Kavitha S., Gunasekaran M., Zhen G., Awasthi M.K., Kumar G. Spent Coffee Grounds Based Circular Bioeconomy: Technoeconomic and Commercialization Aspects. Renew. Sustain. Energy Rev. 2021;152:111721. doi: 10.1016/j.rser.2021.111721. DOI

Semida W.M., Beheiry H.R., Sétamou M., Simpson C.R., Abd El-Mageed T.A., Rady M.M., Nelson S.D. Biochar implications for sustainable agriculture and environment: A review. S. Afr. J. Bot. 2019;127:333–347. doi: 10.1016/j.sajb.2019.11.015. DOI

Mussatto S.I., Machado E.M.S., Martins S., Teixeira J.A. Production, Composition, and Application of Coffee and Its Industrial Residues. Food Bioproc. Tech. 2011;4:661–672. doi: 10.1007/s11947-011-0565-z. DOI

Campos-Vega R., Loarca-Piña G., Vergara-Castañeda H.A., Oomah B.D. Spent Coffee Grounds: A Review on Current Research and Future Prospects. Trends Food Sci. Technol. 2015;45:24–36. doi: 10.1016/j.tifs.2015.04.012. DOI

Tokimoto T., Kawasaki N., Nakamura T., Akutagawa J., Tanada S. Removal of Lead Ions in Drinking Water by Coffee Grounds as Vegetable Biomass. J. Colloid. Interface Sci. 2005;281:56–61. doi: 10.1016/j.jcis.2004.08.083. PubMed DOI

Kovalcik A., Obruca S., Marova I. Valorization of Spent Coffee Grounds: A Review. Food Bioprod. Process. 2018;110:104–119. doi: 10.1016/j.fbp.2018.05.002. DOI

Malaták J., Velebil J., Bradna J., Gendek A., Tamelová B. Evaluation of Co and NoxEmissions in Real-Life Operating Conditions of Herbaceous Biomass Briquettes Combustion. Acta Technol. Agric. 2020;23:53–59.

Richelle M., Tavazzi I., Offord E. Comparison of the Antioxidant Activity of Commonly Consumed Polyphenolic Beverages (Coffee, Cocoa, and Tea) Prepared per Cup Serving. J. Agric. Food Chem. 2001;49:3438–3442. doi: 10.1021/jf0101410. PubMed DOI

Ballesteros L.F., Teixeira J.A., Mussatto S.I. Chemical, Functional, and Structural Properties of Spent Coffee Grounds and Coffee Silverskin. Food Bioproc. Tech. 2014;7:3493–3503. doi: 10.1007/s11947-014-1349-z. DOI

Malara A., Paone E., Frontera P., Bonaccorsi L., Panzera G., Mauriello F. Sustainable Exploitation of Coffee Silverskin in Water Remediation. Sustainability. 2018;10:3547. doi: 10.3390/su10103547. DOI

Cruz R., Cardoso M.M., Fernandes L., Oliveira M., Mendes E., Baptista P., Morais S., Casal S. Espresso Coffee Residues: A Valuable Source of Unextracted Compounds. J. Agric. Food Chem. 2012;60:7777–7784. doi: 10.1021/jf3018854. PubMed DOI

Belitz H.D., Grosch W., Schieberle P. Food Chemistry. Food Chem. 2009:65–69. doi: 10.1007/978-3-540-69934-7. DOI

Pujol D., Liu C., Gominho J., Olivella M.À., Fiol N., Villaescusa I., Pereira H. The Chemical Composition of Exhausted Coffee Waste. Ind Crops Prod. 2013;50:423–429. doi: 10.1016/j.indcrop.2013.07.056. DOI

Fraňková A., Drábek O., Havlík J., Száková J., Vaněk A. The Effect of Beverage Preparation Method on Aluminium Content in Coffee Infusions. J. Inorg. Biochem. 2009;103:1480–1485. doi: 10.1016/j.jinorgbio.2009.06.012. PubMed DOI

Kondamudi N., Mohapatra S.K., Misra M. Spent Coffee Grounds as a Versatile Source of Green Energy. J. Inorg. Biochem. 2008;56:11757–11760. doi: 10.1021/jf802487s. PubMed DOI

Caetano N.S., Silvaa V.F.M., Mata T.M. Valorization of Coffee Grounds for Biodiesel Production. Chem. Eng. Trans. 2012;26:267–272. doi: 10.3303/CET1226045. DOI

McNutt J., He Q. (Sophia) Spent Coffee Grounds: A Review on Current Utilization. J. Ind. Eng. Chem. 2019;71:78–88. doi: 10.1016/j.jiec.2018.11.054. DOI

Mata T.M., Martins A.A., Caetano N.S. Bio-Refinery Approach for Spent Coffee Grounds Valorization. Bioresour. Technol. 2018;247:1077–1084. doi: 10.1016/j.biortech.2017.09.106. PubMed DOI

Bejenari V., Marcu A., Ipate A.M., Rusu D., Tudorachi N., Anghel I., Şofran I.E., Lisa G. Physicochemical Characterization and Energy Recovery of Spent Coffee Grounds. J. Mater. Res. Technol. 2021;15:4437–4451. doi: 10.1016/j.jmrt.2021.10.064. DOI

Tehrani N.F., Aznar J.S., Kiros Y. Coffee Extract Residue for Production of Ethanol and Activated Carbons. J. Clean. Prod. 2015;91:64–70. doi: 10.1016/j.jclepro.2014.12.031. DOI

Colantoni A., Paris E., Bianchini L., Ferri S., Marcantonio V., Carnevale M., Palma A., Civitarese V., Gallucci F. Spent Coffee Ground Characterization, Pelletization Test and Emissions Assessment in the Combustion Process. Sci. Rep. 2021;11:1–14. doi: 10.1038/s41598-021-84772-y. PubMed DOI PMC

Tamelová B., Malaťák J., Velebil J., Gendek A., Aniszewska M. Energy Utilization of Torrefied Residue from Wine Production. Materials. 2021;14:1610. doi: 10.3390/ma14071610. PubMed DOI PMC

Kante K., Nieto-Delgado C., Rangel-Mendez J.R., Bandosz T.J. Spent Coffee-Based Activated Carbon: Specific Surface Features and Their Importance for H 2S Separation Process. J. Hazard. Mater. 2012;201–202:141–147. doi: 10.1016/j.jhazmat.2011.11.053. PubMed DOI

Silva M.A., Nebra S.A., Machado Silva M.J., Sanchez C.G. The Use of Biomass Residues in the Brazilian Soluble Coffee Industry. Biomass Bioenergy. 1998;14:457–467. doi: 10.1016/S0961-9534(97)10034-4. DOI

Li X., Strezov V., Kan T. Energy Recovery Potential Analysis of Spent Coffee Grounds Pyrolysis Products. J. Anal. Appl. Pyrolysis. 2014;110:79–87. doi: 10.1016/j.jaap.2014.08.012. DOI

Sen K.Y., Baidurah S. Renewable Biomass Feedstocks for Production of Sustainable Biodegradable Polymer. Curr. Opin. Green. Sustain. Chem. 2021;27:100412. doi: 10.1016/j.cogsc.2020.100412. DOI

Akbari M., Oyedun A.O., Kumar A. Techno-Economic Assessment of Wet and Dry Torrefaction of Biomass Feedstock. Energy. 2020;207 doi: 10.1016/j.energy.2020.118287. DOI

Tamelová B., Malaťák J., Velebil J. Energy Valorisation of Citrus Peel Waste by Torrefaction Treatment. Agron. Res. 2018;16:276–285. doi: 10.15159/AR.18.029. DOI

Jutakridsada P., Prajaksud C., Kuboonya-Aruk L., Theerakulpisut S., Kamwilaisak K. Adsorption Characteristics of Activated Carbon Prepared from Spent Ground Coffee. Clean. Technol. Env. Policy. 2016;18:639–645. doi: 10.1007/s10098-015-1083-x. DOI

Lee N., Kim S., Lee J. Valorization of Waste Tea Bags via CO2-Assisted Pyrolysis. J. CO2 Util. 2021;44:101414. doi: 10.1016/j.jcou.2020.101414. DOI

Rajesh Banu J., Kavitha S., Yukesh Kannah R., Dinesh Kumar M., Preethi, Atabani A.E., Kumar G. Biorefinery of Spent Coffee Grounds Waste: Viable Pathway towards Circular Bioeconomy. Bioresour. Technol. 2020;302:122821. doi: 10.1016/J.BIORTECH.2020.122821. PubMed DOI

Yang L., He Q., Havard P., Corscadden K., Xu C. (Charles); Wang, X. Co-Liquefaction of Spent Coffee Grounds and Lignocellulosic Feedstocks. Bioresour. Technol. 2017;237:108–121. doi: 10.1016/j.biortech.2017.02.087. PubMed DOI

Lessa E.F., Nunes M.L., Fajardo A.R. Chitosan/Waste Coffee-Grounds Composite: An Efficient and Eco-Friendly Adsorbent for Removal of Pharmaceutical Contaminants from Water. Carbohydr. Polym. 2018;189:257–266. doi: 10.1016/j.carbpol.2018.02.018. PubMed DOI

Levy D., Reinecke J., Manning S. The Political Dynamics of Sustainable Coffee: Contested Value Regimes and the Transformation of Sustainability. J. Manag. Stud. 2016;53:364–401. doi: 10.1111/joms.12144. DOI

Fermoso J., Mašek O. Thermochemical Decomposition of Coffee Ground Residues by TG-MS: A Kinetic Study. J. Anal. Appl. Pyrolysis. 2018;130:249–255. doi: 10.1016/j.jaap.2017.12.007. DOI

Pfluger R.A. Soluble Coffee Processing. Solid Wastes Orig. Collect. Process. Disposal. C.l. Mantell. 1975;39:245–247. doi: 10.3/JQUERY-UI.JS. DOI

Mukherjee A., Borugadda V.B., Dynes J.J., Niu C., Dalai A.K. Carbon Dioxide Capture from Flue Gas in Biochar Produced from Spent Coffee Grounds: Effect of Surface Chemistry and Porous Structure. J. Env. Chem. Eng. 2021;9:106049. doi: 10.1016/j.jece.2021.106049. DOI

Adeleke A.A., Odusote J.K., Ikubanni P.P., Lasode O.A., Malathi M., Paswan D. Essential Basics on Biomass Torrefaction, Densification and Utilization. Int. J. Energy Res. 2021;45:1375–1395. doi: 10.1002/er.5884. DOI

Phanphanich M., Mani S. Impact of Torrefaction on the Grindability and Fuel Characteristics of Forest Biomass. Bioresour. Technol. 2011;102:1246–1253. doi: 10.1016/j.biortech.2010.08.028. PubMed DOI

Kelkar S., Saffron C.M., Chai L., Bovee J., Stuecken T.R., Garedew M., Li Z., Kriegel R.M. Pyrolysis of Spent Coffee Grounds Using a Screw-Conveyor Reactor. Fuel Process. Technol. 2015;137:170–178. doi: 10.1016/j.fuproc.2015.04.006. DOI

Bridgeman T.G., Jones J.M., Williams A., Waldron D.J. An Investigation of the Grindability of Two Torrefied Energy Crops. Fuel. 2010;89:3911–3918. doi: 10.1016/j.fuel.2010.06.043. DOI

Afolabi O.O.D., Sohail M., Cheng Y.L. Optimisation and Characterisation of Hydrochar Production from Spent Coffee Grounds by Hydrothermal Carbonisation. Renew. Energy. 2020;147:1380–1391. doi: 10.1016/j.renene.2019.09.098. DOI

Mayson S., Williams I.D. Applying a Circular Economy Approach to Valorize Spent Coffee Grounds. Resour. Conserv. Recycl. 2021;172 doi: 10.1016/j.resconrec.2021.105659. DOI

Bondarovich H.A., Friedel P., Krampl V., Renner J.A., Shephard F.W., Gianturco M.A. Volatile Constituents of Coffee. Pyrazines and Other Compounds. J. Agric. Food Chem. 1967;15:1093–1099. doi: 10.1021/jf60154a011. DOI

Xie T., Reddy K.R., Wang C., Yargicoglu E., Spokas K. Characteristics and Applications of Biochar for Environmental Remediation: A Review. Crit. Rev. Env. Sci. Technol. 2015;45:939–969. doi: 10.1080/10643389.2014.924180. DOI

Chen Y.C., Jhou S.Y. Integrating Spent Coffee Grounds and Silver Skin as Biofuels Using Torrefaction. Renew. Energy. 2020;148:275–283. doi: 10.1016/j.renene.2019.12.005. DOI

Plaza M.G., González A.S., Pevida C., Pis J.J., Rubiera F. Valorisation of Spent Coffee Grounds as CO2 Adsorbents for Postcombustion Capture Applications. Appl. Energy. 2012;99:272–279. doi: 10.1016/j.apenergy.2012.05.028. DOI

Leoni E., Mancini M., Aminti G., Picchi G. Wood Fuel Procurement to Bioenergy Facilities: Analysis of Moisture Content Variability and Optimal Sampling Strategy. Processes. 2021;9:359. doi: 10.3390/pr9020359. DOI

Hnilička F., Hniličková H., Kudrna J., Kraus K., Kukla J., Kuklová M. Combustion Calorimetry and Its Application in the Assessment of Ecosystems. J. Therm. Anal. 2020;142:771–781. doi: 10.1007/S10973-020-09961-9. DOI

Malaťák J., Gendek A., Aniszewska M., Velebil J. Emissions from Combustion of Renewable Solid Biofuels from Coniferous Tree Cones. Fuel. 2020;276:118001.

Rawat J., Saxena J., Sanwal P. Biochar—An Imperative Amendment for Soil and the Environment. IntechOpen; London, UK: 2019. Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties. DOI

Lehmann J., Joseph S. Biochar for Environmental Management: An Introduction (Pp. 33–46). Biochar for Environmental Management: Science, Technology and Implementation. In: Joseph S., editor. Biochar for Environmental Management: Science and Technology. Earthscan; London, UK: 2015. pp. 33–46.

Cruz R., Mendes E., Torrinha Á., Morais S., Pereira J.A., Baptista P., Casal S. Revalorization of Spent Coffee Residues by a Direct Agronomic Approach. Food Res. Int. 2015;73:190–196. doi: 10.1016/j.foodres.2014.11.018. DOI

Dragone G., Kerssemakers A.A.J., Driessen J.L.S.P., Yamakawa C.K., Brumano L.P., Mussatto S.I. Innovation and Strategic Orientations for the Development of Advanced Biorefineries. Bioresour. Technol. 2020;302:122847. doi: 10.1016/j.biortech.2020.122847. PubMed DOI

Rondon M.A., Lehmann J., Ramírez J., Hurtado M. Biological Nitrogen Fixation by Common Beans (Phaseolus Vulgaris L.) Increases with Bio-Char Additions. Boil. Fertil. Soils. 2006;43:699–708. doi: 10.1007/s00374-006-0152-z. DOI

Spokas K.A., Cantrell K.B., Novak J.M., Archer D.W., Ippolito J.A., Collins H.P., Boateng A.A., Lima I.M., Lamb M.C., McAloon A.J., et al. Biochar: A Synthesis of Its Agronomic Impact beyond Carbon Sequestration. J. Env. Qual. 2012;41:973–989. doi: 10.2134/jeq2011.0069. PubMed DOI

Bruun E.W., Hauggaard-Nielsen H., Ibrahim N., Egsgaard H., Ambus P., Jensen P.A., Dam-Johansen K. Influence of Fast Pyrolysis Temperature on Biochar Labile Fraction and Short-Term Carbon Loss in a Loamy Soil. Biomass Bioenergy. 2011;35:1182–1189. doi: 10.1016/j.biombioe.2010.12.008. DOI

Schmidt H.P., Bucheli T., Kammann C. The European Biochar Certificate (EBC) [(accessed on 13 September 2022)]. Available online: https://www.european-biochar.org/en.

Coffee Plants of the World—Specialty Coffee Association. [(accessed on 26 August 2022)]. Available online: https://sca.coffee/research/coffee-plants-of-the-world.

Malaťák J., Passian L. Heat-Emission Analysis of Small Combustion Equipments for Biomass. Res. Agric. Eng. 2011;57:37–50. doi: 10.17221/28/2010-RAE. DOI

ČSN ISO 1928 (441352) [(accessed on 26 August 2022)]. Available online: https://www.technicke-normy-csn.cz/csn-iso-1928-441352-205351.html.

Dědina M., Jarošíková A., Plíva P., Dubský M. The Effect of Ash Admixture on Compost Quality and Availability of Nutrients. Sustainability. 2022;14:1640. doi: 10.3390/su14031640. DOI

Intani K., Latif S., Islam M.S., Müller J. Phytotoxicity of Corncob Biochar before and after Heat Treatment and Washing. Sustainability. 2018;11:30. doi: 10.3390/su11010030. DOI

Hejátková K., Dvorská I., Jalovecký J., Kohoutek A., Kollárová M., Mičánková K., Plíva P., Valentová L., Vorlíček Z. Kompostování Přebytečné Travní Biomasy. ZERA; Náměšť nad Oslavou, Czech Republic: 2007. [(accessed on 25 August 2022)]. Available online: https://katalog.cbvk.cz/arl-cbvk/cs/detail-cbvk_us_cat-1148269-Kompostovani-prebytecne-travni-biomasy/

Silva M.P., Nieva Lobos M.L., Piloni R.V., Dusso D., González Quijón M.E., Scopel A.L., Moyano E.L. Pyrolytic Biochars from Sunflower Seed Shells, Peanut Shells and Spirulina Algae: Their Potential as Soil Amendment and Natural Growth Regulators. SN Appl. Sci. 2020;2:1–15. doi: 10.1007/s42452-020-03730-x. DOI

Aniszewska M., Gendek A., Hýsek Š., Malat’ák J., Velebil J., Tamelová B. Changes in the Composition and Surface Properties of Torrefied Conifer Cones. Materials. 2020;13:5660. doi: 10.3390/ma13245660. PubMed DOI PMC

Vassilev S.V., Baxter D., Andersen L.K., Vassileva C.G. An Overview of the Chemical Composition of Biomass. Fuel. 2010;89:913–933. doi: 10.1016/j.fuel.2009.10.022. DOI

Mohammad S., Baidurah S., Kamimura N., Matsuda S., Abu Bakar N.A.S., Muhamad N.N.I., Ahmad A.H., Dominic D., Kobayashi T. Fermentation of Palm Oil Mill Effluent in the Presence of Lysinibacillus Sp. LC 556247 to Produce Alternative Biomass Fuel. Sustainability. 2021;13:11915. doi: 10.3390/su132111915. DOI

Zhang L., Xu C., Champagne P. Overview of Recent Advances in Thermo-Chemical Conversion of Biomass. Energy Convers. Manag. 2010;51:969–982. doi: 10.1016/j.enconman.2009.11.038. DOI

Bożym M., Gendek A., Siemiątkowski G., Aniszewska M., Malaťák J. Assessment of the Composition of Forest Waste in Terms of Its Further Use. Materials. 2021;14:973. doi: 10.3390/ma14040973. PubMed DOI PMC

Jenicek L., Neskudla M., Malatak J., Velebil J., Passian L. Spruce and Barley Proximate and ultimate and Stochiometric Analysis Affected by the Impact of Pellet Production and Torrefaction. Acta Technol. Agric. 2021;24:166–172. doi: 10.2478/ATA-2021-0028. DOI

Cerino-Córdova F.J., Dávila-Guzmán N.E., León A.M.G., Salazar-Rabago J.J., Soto-Regalado E. Coffee-Production and Research. IntechOpen; London, UK: 2020. Revalorization of coffee waste. DOI

Cervera-Mata A., Navarro-Alarcón M., Rufián-Henares J.Á., Pastoriza S., Montilla-Gómez J., Delgado G. Phytotoxicity and Chelating Capacity of Spent Coffee Grounds: Two Contrasting Faces in Its Use as Soil Organic Amendment. Sci. Total Environ. 2020;717:137247. doi: 10.1016/j.scitotenv.2020.137247. PubMed DOI

Jiménez-Zamora A., Pastoriza S., Rufián-Henares J.A. Revalorization of Coffee By-Products. Prebiotic, Antimicrobial and Antioxidant Properties. LWT. Food Sci. Technol. 2015;61:12–18. doi: 10.1016/j.lwt.2014.11.031. DOI

Griffith S.M., Banowetz G.M., Gady D. Chemical Characterization of Chars Developed from Thermochemical Treatment of Kentucky Bluegrass Seed Screenings. Chemosphere. 2013;92:1275–1279. doi: 10.1016/j.chemosphere.2013.02.002. PubMed DOI

Ronsse F., van Hecke S., Dickinson D., Prins W. Production and Characterization of Slow Pyrolysis Biochar: Influence of Feedstock Type and Pyrolysis Conditions. GCB Bioenergy. 2013;5:104–115. doi: 10.1111/gcbb.12018. DOI

Pyrolyzed Agro-Food By-Products: A Sustainable Alternative to Coal

Substituting Solid Fossil Fuels with Torrefied Timber Products

The Impact of Nutshell Biochar on the Environment as an Alternative Fuel or as a Soil Amendment

Properties of Biochar Derived from Tea Waste as an Alternative Fuel and Its Effect on Phytotoxicity of Seed Germination for Soil Applications