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Modelling the effects of moisture content in compost piles

Conference Paper


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Abstract


  • This paper considers the self-heating process occurring in a compost pile using

    one- and two-dimensional spatially-dependent models and incorporating terms that

    account for self-heating due to both biological and oxidative mechanisms. Biological

    heat generation is known to be present in most industrial processes handling large

    volumes of bulk organic materials. The heat release rate due to biological activity is

    modelled by a function which is, at sufficiently low temperatures, a monotonically

    increasing function of temperature and, at higher temperatures, a monotonically

    decreasing function of temperature. This functionality represents the fact that microorganisms

    die or become dormant at high temperatures. The heat release rate due to

    oxidation reactions is modelled by Arrhenius kinetics. As moisture is another crucial

    factor in the degradation process of compost, this model consists of four mass-balance

    equations, namely, energy, oxygen, vapour and liquid water concentrations. Analyses

    are undertaken for different initial water contents within the compost pile. We show

    that, when the water content is too low, the reaction is almost negligible whereas, for

    the case when the water content is too high, the reaction only commences when the

    water content evaporates and the water ratio drops into an appropriate range. However,

    for an intermediate water content range, biological reaction is at its optimum and there

    is a possibility of spontaneous combustion of the compost pile.

Authors


  •   Luangwilai, Thiansiri (external author)
  •   Sidhu, Harvinder S. (external author)
  •   Nelson, Mark I.
  •   Chen, Xiao Dong (external author)

Publication Date


  • 2011

Citation


  • Luangwilai, T., Sidhu, H. S., Nelson, M. I. & Chen, X. (2011). Modelling the effects of moisture content in compost piles. CHEMECA 2011: Australian Chemical Engineering Conference Australia: Engineers Australia.

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=9384&context=infopapers

Ro Metadata Url


  • http://ro.uow.edu.au/infopapers/2049

Place Of Publication


  • http://www.conference.net.au/chemeca2011/papers/411.pdf

Abstract


  • This paper considers the self-heating process occurring in a compost pile using

    one- and two-dimensional spatially-dependent models and incorporating terms that

    account for self-heating due to both biological and oxidative mechanisms. Biological

    heat generation is known to be present in most industrial processes handling large

    volumes of bulk organic materials. The heat release rate due to biological activity is

    modelled by a function which is, at sufficiently low temperatures, a monotonically

    increasing function of temperature and, at higher temperatures, a monotonically

    decreasing function of temperature. This functionality represents the fact that microorganisms

    die or become dormant at high temperatures. The heat release rate due to

    oxidation reactions is modelled by Arrhenius kinetics. As moisture is another crucial

    factor in the degradation process of compost, this model consists of four mass-balance

    equations, namely, energy, oxygen, vapour and liquid water concentrations. Analyses

    are undertaken for different initial water contents within the compost pile. We show

    that, when the water content is too low, the reaction is almost negligible whereas, for

    the case when the water content is too high, the reaction only commences when the

    water content evaporates and the water ratio drops into an appropriate range. However,

    for an intermediate water content range, biological reaction is at its optimum and there

    is a possibility of spontaneous combustion of the compost pile.

Authors


  •   Luangwilai, Thiansiri (external author)
  •   Sidhu, Harvinder S. (external author)
  •   Nelson, Mark I.
  •   Chen, Xiao Dong (external author)

Publication Date


  • 2011

Citation


  • Luangwilai, T., Sidhu, H. S., Nelson, M. I. & Chen, X. (2011). Modelling the effects of moisture content in compost piles. CHEMECA 2011: Australian Chemical Engineering Conference Australia: Engineers Australia.

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=9384&context=infopapers

Ro Metadata Url


  • http://ro.uow.edu.au/infopapers/2049

Place Of Publication


  • http://www.conference.net.au/chemeca2011/papers/411.pdf