The effect of the airflow rates and of the aeration mode on the respiration activity of four organic wastes : implications on the composting process
Mejías, Laura (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Komilis, Dimitrios (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)
Sanchez, Antoni (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)

Date:	2017
Abstract:	The aim of this study was to assess the effect of the airflow and of the aeration mode on the composting process of non-urban organic wastes that are found in large quantities worldwide, namely: (i) a fresh, non-digested, sewage sludge (FSS), (ii) an anaerobically digested sewage sludge (ADSS), (iii) cow manure (CM) and (iv) pig sludge (PS). This assessment was done using respirometric indices. Two aeration modes were tested, namely: (a) a constant air flowrate set at three different initial fixed airflow rates, and (b) an oxygen uptake rate (OUR)-controlled airflow rate. The four wastes displayed the same behaviour namely a limited biological activity at low aeration, while, beyond a threshold value, the increase of the airflow did not significantly increase the dynamic respiration indices (DRI₁ max, DRI₂₄ max and AT₄). The threshold airflow rate varied among wastes and ranged from 42 NL air kg⁻¹ DM h⁻¹ for CM and from 67 to 77 NL air kg⁻¹ DM h⁻¹ for FSS, ADSS and PS. Comparing the two aeration modes tested (constant air flow, OUR controlled air flow), no statistically significant differences were calculated between the respiration activity indices obtained at those two aeration modes. The results can be considered representative for urban and non-urban organic wastes and establish a general procedure to measure the respiration activity without limitations by airflow. This will permit other researchers to provide consistent results during the measurement of the respiration activity. Results indicate that high airflows are not required to establish the maximum respiration activity. This can result in energy savings and the prevention of off-gas treatment problems due to the excessive aeration rate in full scale composting plants.
Note:	Dimitrios Komilis wishes to thank Tecniospring for the financial support during years 2014-2016 in Universitat Autonoma de Barcelona (project no. TECSPR13-1-0006, ACCIÓ, Government of Catalonia).
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió sotmesa a revisió
Subject:	Dynamic respirometric index ; Oxygen uptake rate ; Composting ; Airflow ; Biological activity
Published in:	Waste management, Vol. 65 (July 2017) , p. 22-28, ISSN 0956-053X

DOI: 10.1016/j.wasman.2017.04.008

Preprint 31 p, 435.8 KB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Engineering > Composting Research Group (GICOM)
Articles > Research articles
Articles > Published articles