Fouling behavior and mechanism of hydrophilic modified membrane in anammox membrane bioreactor: Role of gel layer

Membrane hydrophilic modification has been applied as an effective antifouling strategy for aerobic and anaerobic heterotrophic membrane bioreactors (MBRs), while its performance remains unclear ammonium oxidation (anammox) MBR. Herein, membranes (Mh) modified from pristine nylon fabric meshes (Mp, pore size of 20 μm), were in long-term operation anammox Although the average flux Mh was 90.7% higher than that Mp (p < 0.05) filtered with model foulant (bovine serum albumin) a dead-end filtration test, cycle MBR 37.9% shorter synthesized wastewater, spite comparable total nitrogen removal efficiency (over 80%) achieved. A thin compact gel layer formed on by adsorption polysaccharide further gelation protein colloidal biomass. The bound water wrapped brought about 32.8% resistance, caused 81.3% contribution rate decline concentration polarization, compared Mp. Moreover, more microbial metabolites, especially (23.9% vs. 17.7%), rejected Mp, providing organic matters proliferation bacteria, leading to decreased relative abundance bacteria (from 63.2% 35.2%). We proposed formation process revealed fouling mechanism MBR, significant theoretical foundation control systems.