Factors affecting air pycnometer performance for its use in the composting process
Ruggieri, Luz (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Gea Leiva, Teresa (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Artola Casacuberta, Adriana (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Sanchez, Antoni (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)

Data:	2009
Resum:	Air filled porosity (AFP) is a crucial factor in composting to guarantee aerobic conditions inside the composting matrix. Among the different methods proposed to measure AFP in composting processes, air pycnometry is defined as the most adequate. There is a lack of a standard methodology for air pycnometry utilization for AFP determination in heterogeneous samples as those from composting materials. Air pycnometers currently used for this purpose are custom made instruments operating under different conditions (sample volume, initial pressure, etc. ). All factors affecting air pycnometry accuracy in the composting process are related to the proper maintenance and handling of the air pycnometer and the composting sample. In this study, AFP measurements have been performed in more than 50 samples of a wide range of composting materials using two different custom made pycnometers, one of them coupled to a composting reactor allowing in situ AFP measurement. While temperature variation during AFP measurement has been discarded as an error source, the determination of the sample volume has been found to be a significant factor affecting the air filled porosity calculation. Regarding the initial pressure to use, a compromise between accuracy and practicality has to be established for each pycnometer design as AFP values obtained with diverse initial pressures (from 200 to 500 kPa gauge pressure) were found to present no statistical differences. An initial pressure in the range of 300-500 kPa (gauge pressure) is recommended. In conclusion, there is a need for a standard methodology for AFP determination or prediction at industrial scale. A complete procedure for air filled porosity determination by air pycnometry is also presented in this work.
Ajuts:	Ministerio de Educación y Ciencia CTM2006-00315/TECNO
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió sotmesa a revisió
Publicat a:	Compost science and utilization, Vol. 17, issue 4 (2009) , ISSN 1065-657X

DOI: 10.1080/1065657X.2009.10702433

Pre-print 34 p, 775.0 KB

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Documents de recerca > Documents dels grups de recerca de la UAB > Centres i grups de recerca (producció científica) > Enginyeries > Grup de Recerca en Compostatge (GICOM)
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