Skip to main content

Potential Bio-oil Production from Smouldering Combustion of Faeces


This study examined the potential bio-oil production from the smouldering combustion of faeces mixed with sand, through a series of experiments. Surrogate faeces, with demonstrated equivalence to human faeces, were used in order to minimize variability in the composition. The yield of bio-oil was studied as a function of the following experimental parameters: original moisture content of the faeces, airflow rate and sand-to-faeces mass ratio. The amount of bio-oil collected was shown to be dependent on the airflow rate and the relative amount of sand used but independent on the moisture content. The bio-oil obtained was characterized by ultimate analysis, water content and calorific value. Under the experimental conditions studied, up to 70 g of bio-oil per kg of dry faeces (HHV = 27.6 kJ/g) can be produced. Finally, experiments demonstrated that sand can be reused after each experiment. The effect of the ash accumulation in the sand matrix on smouldering was investigated over five successive tests with the same batch of sand. The implementation of this technology to other type of organic waste would contribute to the development of an integrated waste treatment technology, in combination with bio-oil production.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10


  1. 1.

    Lute, M.L., Attari, S.Z., Sherman, S.J.: Don’t rush to flush. J. Environ. Psychol. 43, 105–111 (2015). doi:10.1016/j.jenvp.2015.06.003

    Article  Google Scholar 

  2. 2.

    Anand, C.K., Apul, D.S.: Composting toilets as a sustainable alternative to urban sanitation—a review. Waste Manag. 34(2), 329–343 (2014). doi:10.1016/j.wasman.2013.10.006

    Article  Google Scholar 

  3. 3.

    Rose, C., Parker, A., Jefferson, B., Cartmell, E.: The characterization of feces and urine: a review of the literature to inform advanced treatment technology. Crit. Rev. Environ. Sci. Technol. 45(17), 1827–1879 (2015). doi:10.1080/10643389.2014.1000761

    Article  Google Scholar 

  4. 4.

    Yermán, L., Hadden, R.M., Pironi, P., Torero, J.L., Gerhard, J.I., Carrascal, J., Krajcovic, M., Fabris, I., Cormier, D., Cheng, Y.-L.: Smouldering combustion as a treatment technology for faeces: exploring the parameter space. Fuel 147, 108–116 (2015). doi:10.1016/j.fuel.2015.01.055

    Article  Google Scholar 

  5. 5.

    Mitchell, L.: U of T engineers win third place in Gates Foundation toilet challenge. U of T News (2012)

  6. 6.

    Cheng, Y.-L., Kortschot, M.T., Gerhard, J.I., Torero, J.L., Saini, R., Fernandes, A.X., Fishman, Z., Bartczak, T., Liao, D., Fabris, I., Cormier, D., Carrascal, J., Yermán, L.: A Household Sanitation Process Based on Integrated Diversion/Dewatering, Drying/Smoldering of Solid Waste, and Pasteurization of Liquid Waste. Paper presented at the third international fecal sludge management conference

  7. 7.

    Carvalho, E.R., Gurgel Veras, C.A., Carvalho Jr., J.A.: Experimental investigation of smouldering in biomass. Biomass Bioenergy 22(4), 283–294 (2002). doi:10.1016/S0961-9534(02)00005-3

    Article  Google Scholar 

  8. 8.

    Rein, G.: Smouldering combustion phenomena in science and technology. Int. Rev. Chem. Eng. 1, 3–18 (2009)

    Google Scholar 

  9. 9.

    Switzer, C., Pironi, P., Gerhard, J.I., Rein, G., Torero, J.L.: Self-sustaining smoldering combustion: a novel remediation process for non-aqueous-phase liquids in porous media. Environ. Sci. Technol. 43, 5871–5877 (2009)

    Article  Google Scholar 

  10. 10.

    Ohlemiller, T.J.: Smouldering combustion. In: DiNenno, P.J., Drysdale, D., Beyler, C.L., Walton, W.D. (eds.) SFPE Handbook of Fire Protection Engineering, p. 2-200-202-210. National Fire Protection Association, Quincy (2008)

    Google Scholar 

  11. 11.

    Vantelon, J.P., Lodeho, B., Pignoux, S., Ellzey, J.L., Torero, J.L.: Experimental observations on the thermal degradation of a porous bed of tires. Proc. Combust. Inst. 30(2), 2239–2246 (2005). doi:10.1016/j.proci.2004.08.109

    Article  Google Scholar 

  12. 12.

    Switzer, C., Pironi, P., Gerhard, J.I., Rein, G., Torero, J.L.: Volumetric scale-up of smouldering remediation of contaminated materials. J. Hazard. Mater. 268, 51–60 (2014). doi:10.1016/j.jhazmat.2013.11.053

    Article  Google Scholar 

  13. 13.

    Pironi, P., Switzer, C., Rein, G., Fuentes, A., Gerhard, J.I., Torero, J.L.: Small-scale forward smouldering experiments for remediation of coal tar in inert media. Proc. Combust. Inst. 32(2), 1957–1964 (2009). doi:10.1016/j.proci.2008.06.184

    Article  Google Scholar 

  14. 14.

    Torero, J.L., Fernandez-Pello, A.C.: Forward smolder of polyurethane foam in a forced air flow. Combust. Flame 106(1–2), 89–109 (1996). doi:10.1016/0010-2180(95)00245-6

    Article  Google Scholar 

  15. 15.

    Anca-Couce, A., Zobel, N., Berger, A., Behrendt, F.: Smouldering of pine wood: kinetics and reaction heats. Combust. Flame 159(4), 1708–1719 (2012). doi:10.1016/j.combustflame.2011.11.015

    Article  Google Scholar 

  16. 16.

    Pironi, P., Switzer, C., Gerhard, J.I., Rein, G., Torero, J.L.: Self-sustaining smoldering combustion for NAPL remediation: laboratory evaluation of process sensitivity to key parameters. Environ. Sci. Technol. 45, 2980–2986 (2011)

    Article  Google Scholar 

  17. 17.

    Yermán, L., Wall, H., Torero, J.L., Gerhard, J.I., Cheng, Y.-L.: Smoldering combustion as a treatment technology for faeces: sensitivity to key parameters. Combust. Sci. Technol. (2016). doi:10.1080/00102202.2015.1136299

    Google Scholar 

  18. 18.

    Wall, H., Yermán, L., Gerhard, J., Fabris, I., Cormier, D., Cheng, Y.-L., Torero, J.L.: Investigation of self-sustaining smouldering of faeces: key parameters and scaling effects. In: Dynamic Ecolibrium: Sustainable Engineering Society Conference (SENG 2015), p. 113 (2015)

  19. 19.

    Yermán, L., Wall, H., Torero, J.L., Gerhard, J.I., Fabris, I., Cormier, D., Cheng, Y.-L.: Self-sustaining smouldering combustion of faeces as treatment and disinfection method. Paper presented at the APCChE 2015 congress incorporating Chemeca 2015, Melbourne, Australia

  20. 20.

    Yermán, L., Wall, H., Torero, J.L.: Experimental Investigation on the Destruction Rates of Organic Waste with High Moisture Content by Means of Self-sustained Smouldering Combustion. Paper presented at the thirty-sixth international symposium on combustion, Seoul, Korea, July 31–August 5 (2016)

  21. 21.

    Rashwan, T.L., Gerhard, J.I., Grant, G.P.: Application of self-sustaining smouldering combustion for the destruction of wastewater biosolids. Waste Manag. (2016). doi:10.1016/j.wasman.2016.01.037

    Google Scholar 

  22. 22.

    Wignarajah, K., Litwill, E., Fisher, J.W., Hogan, J.: Simulated human feces for testing human waste processing technologies in space systems. SAE Tech. Pap. Ser. 01(2180), 424–429 (2006). doi:10.4271/2006-01-2180

    Google Scholar 

  23. 23.

    Girovich, M.J.: Biosolids Treatment and Management: Processes for Beneficial Use. Taylor & Francis, London (1996)

    Google Scholar 

  24. 24.

    Lovelady, H.G., Stork, E.J.: An improved method for preparation of feces for bomb calorimetry. Clin. Chem. 16(3), 253–254 (1970)

    Google Scholar 

  25. 25.

    Spellman, F.R.: Incinerating Biosolids. Taylor & Francis, London (1997)

    Google Scholar 

  26. 26.

    Yadav, K.D., Tare, V., Ahammed, M.M.: Vermicomposting of source-separated human faeces for nutrient recycling. Waste Manag. 30(1), 50–56 (2010). doi:10.1016/j.wasman.2009.09.034

    Article  Google Scholar 

  27. 27.

    Rein, G., Cohen, S., Simeoni, A.: Carbon emissions from smouldering peat in shallow and strong fronts. Proc. Combust. Inst. 32(2), 2489–2496 (2009). doi:10.1016/j.proci.2008.07.008

    Article  Google Scholar 

  28. 28.

    Wang, S.: High-efficiency separation of bio-oil. In: Darko, M. (ed.) Biomass Now—Sustainable Growth and Use. InTech, Open Access (2013)

  29. 29.

    Jacobson, K., Maheria, K.C., Kumar Dalai, A.: Bio-oil valorization: a review. Renew. Sustain. Energy Rev. 23, 91–106 (2013). doi:10.1016/j.rser.2013.02.036

    Article  Google Scholar 

  30. 30.

    Xu, Y., Hu, X., Li, W., Shi, Y.: Preparation and characterization of bio-oil from biomass. Prog. Biomass Bioenergy Prod. (2011). doi:10.5772/16466

    Google Scholar 

  31. 31.

    Teella, A.V.P.R.: Separation of Carboxylic Acids from Aqueous Fraction of Fast Pyrolysis Bio-oils Using Nanofiltration and Reverse Osmosis Membranes. University of Massachusetts, Amherst (2011)

    Google Scholar 

Download references


This work was supported by the Bill and Melinda Gates Foundation. We acknowledge Zachary Fishman and Harrison Wall for faeces characterization, Brett MacDonald and Tommy Kokas for ash content, and Kieran J. May and Dustin J. W. Brown for condensate measurements.

Author information



Corresponding author

Correspondence to L. Yermán.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Yermán, L., Cormier, D., Fabris, I. et al. Potential Bio-oil Production from Smouldering Combustion of Faeces. Waste Biomass Valor 8, 329–338 (2017).

Download citation


  • Faeces valorization
  • Smouldering combustion
  • Bio-oil
  • Waste treatment