Understanding the factors affecting the self-heating process of compost piles: Two-dimensional analysis

Industrial compost piles contain large volumes of bulk organic materials. Normally, there are two main heat generation processes—oxidation of cellulosic materials and biological activity within the compost pile. Biological heating occurs at a lower temperature range, but it may `kick-start' the oxidation reaction. Nevertheless, biological heating is desirable and is a key component in composting operations. However, there are cases when the temperature within the compost piles increases beyond the ignition temperature of cellulosic materials which can result in spontaneous ignition. This investigation considers the self-heating process that occurs in a compost pile using a two-dimensional spatially-dependent model incorporating terms that account for self-heating due to both biological and oxidative mechanisms. The variation of temperature distribution within different pile geometries is examined. References P. C. Bowes. Self heating: evaluating and controlling the hazard. Amsterdam: Elsevier Press, 1984 W. F. Brinton, Jr. E. Evans, M. L. Droffner, and R. B. Brinton. Standardized test for evaluation of compost self-heating. BioCycle 36 (1995), pp. 60–65 M. Escudey, A. Arias, J. Forster, N. Moraga, C. Zambra, and A. C. Chang. Sewage sludge self-heating and spontaneous combustion. Field, laboratory and numerical studies. High Temp. Mater. Proc. 27.5 (2008), pp. 337–346. doi: 10.1515/HTMP.2008.27.5.337 R. T. Haug. The Practical Handbook of Compost Engineering. USA: Lewis Publishers, 1993. doi: 10.1201/9780203736234 W. Hogland, T. Bramryd, and I. Persson. Physical, biological and chemical effects of unsorted fractions of industrial solid waste in waste fuel storage. Waste Manage. Res. 14.2 (1996), pp. 197–210. doi: 10.1006/wmre.1996.0019 P. F. Hudak. Spontaneous combustion of shale spoils at sanitary landfill. Waste Manage. Res. 22.6 (2002), pp. 687–688. doi: 10.1016/s0956-053x(01)00077-0 F. Kuwahara, Y. Sano, A. Nakayama, K. Nakasaki, and T. Fukazawa. Numerical modelling of a composting process with aeration. J. Porous Media 12.10 (2009), pp. 927–938. doi: 10.1615/JPorMedia.v12.i10.10 T. Luangwilai and H. S. Sidhu. Determining critical conditions for two dimensional compost piles with air flow via numerical simulations. Proceedings of the 15th Biennial Computational Techniques and Applications Conference, CTAC-2010. Ed. by W. McLean and A. J. Roberts. Vol. 52. ANZIAM J. 2011, pp. C463–C481. doi: 10.21914/anziamj.v52i0.3753 T. Luangwilai, H. S. Sidhu, and M. I. Nelson. A two dimensional, reaction-diffusion model of compost piles. Proceedings of the 10th Biennial Engineering Mathematics and Applications Conference, EMAC-2011. Ed. by M. Nelson, M. Coupland, H. Sidhu, T. Hamilton, and A. J. Roberts. Vol. 53. ANZIAM J. 2012, pp. C34–C52. doi: 10.21914/anziamj.v53i0.5083 T. Luangwilai, H. S. Sidhu, and M. I. Nelson. One-dimensional spatial model for self-heating in compost piles: Investigating effects of moisture and air flow. Food Bioprod. Process. 108 (2018), pp. 18–26. doi: 10.1016/j.fbp.2017.12.001 T. Luangwilai, H. S. Sidhu, and M. I. Nelson. Understanding effects of ambient humidity on self-heating of compost piles. CHEMECA 2018. Institution of Chemical Engineers. 2018, p. 68. url: https://search.informit.org/doi/10.3316/informit.049196748938234 T. Luangwilai, H. S. Sidhu, and M. I. Nelson. Understanding the role of moisture in the self-heating process of compost piles. CHEMECA 2012. Engineers Australia. 2012, pp. 1834–1846. url: https://search.informit.org/doi/10.3316/INFORMIT.867764346204981 T. Luangwilai, H. S. Sidhu, M. I. Nelson, and X. D. Chen. Biological self-heating of compost piles with airflow. CHEMECA 2009. Engineers Australia. 2009, pp. 2683–2692. url: https://search.informit.org/doi/10.3316/informit.799299549211365 T. Luangwilai, H. S. Sidhu, M. I. Nelson, and X. D. Chen. Modelling air flow and ambient temperature effects on the biological self-heating of compost piles. Asia-Pacific J. Chem. Eng. 5.4 (2010), pp. 609–618. doi: 10.1002/apj.438 T. Luangwilai, H. S. Sidhu, M. I. Nelson, and X. D. Chen. Modelling the effects of air flow, ambient temperature and radiative boundary conditions in compost piles. CHEMECA 2010. Engineers Australia. 2010, pp. 3585–3596. url: https://search.informit.org/doi/10.3316/informit.484992904303574 T. Luangwilai, H. S. Sidhu, M. I. Nelson, and X. D. Chen. Modelling the effects of moisture content in compost piles. CHEMECA 2011. Engineers Australia. 2011, pp. 1473–1484. url: https://search.informit.org/doi/10.3316/informit.174710980721893 T. Luangwilai, S. D. Watt, S. Fu, H. S. Sidhu, and M. I. Nelson. Modelling the effects of ambient temperature variation on self-heating process of compost piles. Engineers Australia (2019), pp. 84–96. url: https://search.informit.org/doi/10.3316/informit.689351109484953 N. O. Moraga, F. Corvalan, M. Escudey, A. Arias, and C. E. Zambra. Unsteady 2D coupled heat and mass transfer in porous media with biological and chemical heat generations. Int. J. Heat Mass Trans. 52 (2009), pp. 5841–5848. doi: 10.1016/j.ijheatmasstransfer.2009.07.027 PDE Solutions Inc. FlexPDE v 6.05. PDE Solutions Inc. Cambridge MA, 2009. url: http://www.pdesolutions.com R. Rynk. Fires at composting facilities: causes and conditions Part I. BioCycle 41.1 (2000), pp. 54–58 H. S. Sidhu, M. I. Nelson, and X. D. Chen. A simple spatial model for self-heating compost piles. Proceedings of the 13th Biennial Computational Techniques and Applications Conference, CTAC-2006. Ed. by W. Read and A. J. Roberts. Vol. 48. ANZIAM J. 2007, pp. C135–C150. doi: 10.21914/anziamj.v48i0.8