Abstract: Membrane bioreactors (MBRs) have been widely used during last decades for wastewater treatment worldwide in large-scale plants, due to their various advantages, such as excellent effluent quality, occupation of small land area, low hydraulic retention time (HRT), higher solids retention time (SRT) and lower sludge production. However, they present a major disadvantage that resides in energy consumption, which is attributed to membrane fouling problem. Membrane fouling is caused by the accumulation and deposition of activated sludge substances on the surface and in the pores of the membrane. Membrane fouling leads to increase in trans-membrane pressure (TMP) by reducing the membrane permeability. Extensive studies have been performed aiming to search and explain the membrane fouling mechanism, as well as to confront it. According to such research works, irreversible membrane fouling has been attributed to the gradual deposition and aggregation of SMP within the membrane pores resulting in pore blockage and increased TMP. The irreversible membrane foulingin most cases has been semi-confronted with chemical cleaning of the membrane, usually in a special facility outside the MBR system, which implies considerable labor costs. In this research work an innovative method was investigated in pilot-real scale MBR, whereindigenous filamentous microorganisms of the bioreactor were used. The MBR unit consisted of a denitrification tank of dissolved oxygen DO = 0.2±0.05 mg/L, an aerated/filamentous’ growth tank of DO =0.5±0.3 mg/L and an aerated tank of DO= 2.5±0.5 mg/L. The controlled growth of filaments was achieved in this MBR unit, favouring the creation of sludge with high porosity, contributing to reduction of membrane fouling.

Keywords: Membrane Fouling; Membrane Bioreactor; Dissolved Oxygen; Trans-Membrane Pressure

Biography: Petros Samaras is Professor of Water Technology and Environmental Protection, at the Department of Food Science and Technology of the International Hellenic University. He holds a PhD in Chemical Engineering from University of Thessaloniki. He has expertise on the application of physical, chemical and biological methods for water and wastewater treatment towards the removal of solids and dissolved organic substances and nutrients and energy recovery from byproducts. He has participated in more than 50 national and international research and demonstration projects, funded by E.U. and national sources (ministries, industries, companies etc.). He has 125 publications in journals and h-index=30 (scopus); more than 100 presentations in international conferences; 6 chapters in books; 1 EU patent. Reviewer of research project proposals in EU and Greece; Consulting engineer in public/private enterprises related to the examination of water-wastewater quality, control/optimization of the operation of WWTPs and energy recovery from byproducts.