2.2. Membrane setup and membrane
A hollow-fiber ultra-filtration membrane module was used (LU8-4A, Litree Company, China). The membrane was the cross-flow type. The membrane was made of hydrophilized polyvinyl chloride, and the module had an effective membrane surface area of 0.16 m2. The molecular weight cutoff as specified by the manufacturer was 100,000 Dalton, and the nominal pore size was 0.01 μm. The internal and external diameter of the hollow filament fibers was 1.00 mm and 1.66 mm, respectively. The manufacturer's specified operating pressure range was 0.1–0.2 MPa, and the maximum flux was 200 L/(m2 • h). A schematic diagram of PSB-MBR and the detailed operation processing as supporting information are attached in the e-component.