Influence of organic loading rate on membrane fouling in membrane separation activated sludge process

A Laboratory-scale experiment was conducted to investigate the influence of organic loading rate to a reactor on the bio fouling in a membrane separation activated sludge system. A flat-sheet-type membrane module was used and the change of the pressure and the filtration resistance were measured. Using synthetic substrate, TOC loading rate was set in the range between 0.3 g l^–1 day^–1 and 1.5g l^–1 day^–1. Also an experiment on the consolidation characteristics of sludge accumulated on membrane was conducted. A mathematical model was developed to simulate temporal changes of suction pressure, flux and filtration resistance considering accumulation, detachment and consolidation of bacterial extracellular polymers on the membrane surface. A reactor with higher loading rate showed sudden increase of trans-membrane pressure, while a reactor with lower loading rate showed delayed increase of the pressure. The experimental results were simulated well by the developed model.