Farshid Pajoum Shariati - School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box ۱۱۱۵۵-۴۵۶۳, Tehran, Iran . IEM, Université Montpellier ۲,F-۳۴۰۹۵ Montpellier, France
Mohammad Reza Mehrnia - School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box ۱۱۱۵۵-۴۵۶۳, Tehran, Iran
Mohammad Hossien Sarrafzadeh - School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box ۱۱۱۵۵-۴۵۶۳, Tehran, Iran
Sara Rezaee - School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box ۱۱۱۵۵-۴۵۶۳, Tehran, Iran

In this study, the respirometric activity of activated sludge in the novel hybrid membrane biorector with different organic loading rate (2-6 kg COD. m-3.d-1) was investigated. The concentration of COD in the permeat was lower than 20 mg COD.l-1 and the concentarion of COD in the supernatant at the long term operation system increased. The respirometric activity of activated sludge in the first period ( CODs belowe the 75 mgCOD.l-1 )increased with increasing MLSS and organic laoding rate. Also, respirometric activity decreased with decreasing HRT from 24 to 14h.It was observed at the long term operation when substrate overload occurred, induced a high concentration of COD soluble and polysaccharide concentration in supernatant and a significant decreased the respirometric actvity of activated sludge

hybrid membrane bioreactor, Respirometric activity, organic loading rate