Towards integrated operation of membrane bioreactors: effects of aeration on biological and filtration performance

Abstract

Two experimental studies evaluated the effect of aerobic and membrane aeration changes on sludge properties, biological nutrient removal and filtration processes in a pilot plant membrane bioreactor. The optimal operating conditions were found at an aerobic dissolved oxygen set-point (DO) of 0.5mgO2L-1 and a membrane specific aeration demand (SADm) of 1mh-1, where membrane aeration can be used for nitrification. Under these conditions, a total flow reduction of 42% was achieved (75% energy reduction) without compromising nutrient removal efficiencies, maintaining sludge characteristics and controlled filtration. Below these optimal operating conditions, the nutrient removal efficiency was reduced, increasing 20% for soluble microbial products, 14% for capillarity suction time and reducing a 15% for filterability. Below this DO set-point, fouling increased with a transmembrane pressure 75% higher. SADm below 1mh-1 doubled the values of transmembrane pressure, without recovery after achieving the initial conditions

The research leading to these results has received funding from the Spanish Ministry of Economy and Competitiveness (CTM2012-38314-C02-01 and PCIN-2013-074) and from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme (FP7/2007-2013, under REA agreement 289193 (SANITAS) and under REA agreement 600388 (TECNIOSPRING)). This publication reflects only the authors' views, and the European Union is not liable for any use that may be made of the information contained therein. Montse Dalmau received a grant from the Spanish Ministry of Economy and Competitiveness (BES-2010-033288)