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Predicting biodegradable volatile solids degradation profiles in the composting process.
Waste Manag. 2009 Feb; 29(2):559-69.WM

Abstract

This paper presents a new method for the prediction of the pattern of biodegradable volatile solids (BVS) degradation in the composting process. The procedure is based on a re-arrangement of the heat balance around a composting system to numerically solve for the rate of BVS carbon (BVS-C) disappearance. Input data for the model was obtained from composting experiments conducted in a laboratory-scale, constant temperature difference (CTD) reactor simulating a section of an aerated static pile, and using a simulated feedstock comprising ostrich feed, shredded paper, finished compost and woodchips. These experiments also provided validation data in the form of exit gas CO(2) carbon (CO(2)-C) profiles. The model successfully predicted the generic shape of experimental substrate degradation profiles obtained from CO(2) measurements, but under the conditions and assumptions of the experiment, the profiles were quantitatively different, giving an over-estimate of BVS-C. Both measured CO(2)-C and predicted BVS-C profiles were moderately to well fitted by a single exponential function, with replicated rate coefficient values of 0.08 and 0.09 d(-1), and 0.06 and 0.07 d(-1), respectively. In order to explore the underlying shape of the profiles, measured and predicted data at varying temperature were corrected to a constant temperature of 40 degrees C, using the temperature correction function of Rosso et al. [Rosso, L., Lobry, J.R., and Flandrois, J.P., 1993. An unexpected correlation between cardinal temperatures of microbial growth highlighted by a new model. Journal of Theoretical Biology, 162, 447-463], with cardinal temperatures of 5, 59 and 85 degrees C. Multi-phase profiles were generated for both the measured CO(2)-C and the predicted BVS-C data in this case. However, when alternative cardinal temperatures of 5, 55 and 80 degrees C, or 5, 50 and 80 degrees C, were used, the predicted profiles assumed an exponential shape, and excellent fits were obtained using a double exponential function. These findings support the argument that a substrate degradation curve generated under laboratory conditions at 40 degrees C, would, given correct cardinal temperatures, generate a correct substrate degradation profile under varying temperature conditions and that this in turn would enable an accurate and precise prediction of the temperature profile, using a heat and mass balance approach. In order to realise this prospect, it is proposed that further work to obtain experimental data under completely mixed conditions, more accurately estimate the overall heat transfer coefficient and obtain correct values for the cardinal temperatures used in the temperature correction function, is required.

Authors+Show Affiliations

Department of Civil and Natural Resources Engineering, University of Canterbury, Christchurch, New Zealand. ian.mason@canterbury.ac.nz

Pub Type(s)

Journal Article

Language

eng

PubMed ID

18572400

Citation

Mason, I G.. "Predicting Biodegradable Volatile Solids Degradation Profiles in the Composting Process." Waste Management (New York, N.Y.), vol. 29, no. 2, 2009, pp. 559-69.
Mason IG. Predicting biodegradable volatile solids degradation profiles in the composting process. Waste Manag. 2009;29(2):559-69.
Mason, I. G. (2009). Predicting biodegradable volatile solids degradation profiles in the composting process. Waste Management (New York, N.Y.), 29(2), 559-69. https://doi.org/10.1016/j.wasman.2008.05.001
Mason IG. Predicting Biodegradable Volatile Solids Degradation Profiles in the Composting Process. Waste Manag. 2009;29(2):559-69. PubMed PMID: 18572400.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Predicting biodegradable volatile solids degradation profiles in the composting process. A1 - Mason,I G, Y1 - 2008/06/24/ PY - 2007/08/13/received PY - 2008/04/17/revised PY - 2008/05/01/accepted PY - 2008/6/24/pubmed PY - 2009/3/7/medline PY - 2008/6/24/entrez SP - 559 EP - 69 JF - Waste management (New York, N.Y.) JO - Waste Manag VL - 29 IS - 2 N2 - This paper presents a new method for the prediction of the pattern of biodegradable volatile solids (BVS) degradation in the composting process. The procedure is based on a re-arrangement of the heat balance around a composting system to numerically solve for the rate of BVS carbon (BVS-C) disappearance. Input data for the model was obtained from composting experiments conducted in a laboratory-scale, constant temperature difference (CTD) reactor simulating a section of an aerated static pile, and using a simulated feedstock comprising ostrich feed, shredded paper, finished compost and woodchips. These experiments also provided validation data in the form of exit gas CO(2) carbon (CO(2)-C) profiles. The model successfully predicted the generic shape of experimental substrate degradation profiles obtained from CO(2) measurements, but under the conditions and assumptions of the experiment, the profiles were quantitatively different, giving an over-estimate of BVS-C. Both measured CO(2)-C and predicted BVS-C profiles were moderately to well fitted by a single exponential function, with replicated rate coefficient values of 0.08 and 0.09 d(-1), and 0.06 and 0.07 d(-1), respectively. In order to explore the underlying shape of the profiles, measured and predicted data at varying temperature were corrected to a constant temperature of 40 degrees C, using the temperature correction function of Rosso et al. [Rosso, L., Lobry, J.R., and Flandrois, J.P., 1993. An unexpected correlation between cardinal temperatures of microbial growth highlighted by a new model. Journal of Theoretical Biology, 162, 447-463], with cardinal temperatures of 5, 59 and 85 degrees C. Multi-phase profiles were generated for both the measured CO(2)-C and the predicted BVS-C data in this case. However, when alternative cardinal temperatures of 5, 55 and 80 degrees C, or 5, 50 and 80 degrees C, were used, the predicted profiles assumed an exponential shape, and excellent fits were obtained using a double exponential function. These findings support the argument that a substrate degradation curve generated under laboratory conditions at 40 degrees C, would, given correct cardinal temperatures, generate a correct substrate degradation profile under varying temperature conditions and that this in turn would enable an accurate and precise prediction of the temperature profile, using a heat and mass balance approach. In order to realise this prospect, it is proposed that further work to obtain experimental data under completely mixed conditions, more accurately estimate the overall heat transfer coefficient and obtain correct values for the cardinal temperatures used in the temperature correction function, is required. SN - 0956-053X UR - https://www.unboundmedicine.com/medline/citation/18572400/Predicting_biodegradable_volatile_solids_degradation_profiles_in_the_composting_process_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0956-053X(08)00150-5 DB - PRIME DP - Unbound Medicine ER -