1 The importance of aeration mode and flowrate in the determination of the biological activity and stability of organic wastes by respiration indices Natividad Almeira, Dimitrios Komilis, Raquel Barrena, Teresa Gea, Antoni Sánchez* Composting Research Group (GICOM) Dept. of Chemical Engineering Universitat Autònoma de Barcelona 08193-Bellaterra (Barcelona, Spain) *Corresponding author: Dr. Antoni Sánchez: antoni.sanchez@uab.cat Tel.: +34-935811019