MBR technology has obvious advantages over conventional activated sludge process such as high pollutant removal efficiency, complete solid–liquid separation and little sludge waste. However, high membrane cost, intensive energy consumption and serious membrane fouling limited its wide application. Therefore, low-cost filters, such as nonwoven, mesh and filter cloth have been applied to substitute traditional membranes. Nonwoven has the properties of variable pore size distribution, inexpensive price and uncomplicated design. It has been reported that nonwoven MBR process has good performance in water quality and the filtration flux of 20-30 LMH could be obtained. The nonwoven fabric filter bag used as MBR under gravity has also been applied for wastewater reclamation. However, nonwoven is relatively hydrophobic, which results in serious fouling and membrane life is also shortened.
A research conducted at Shanghai University of Engineering Science in China aims to find simple ways to improve the hydrophilicity of nonwoven surface. One simple method relevant to this paper is to coat diatomite/iron oxide on nonwoven surface. After that, the modified nonwoven membrane is placed in the reactor and its filtration performance is described.