Effective control of DBPs formation and membrane fouling in catalytic ozonation membrane reactor for municipal wastewater reclamation

Abstract

This study aimed to evaluate the performance of different ceramic membranes, namely CuMn2O4 (CMO), g-C3N4 (CN), and CuMn2O4/g-C3N4 (CMO/CN) ceramic membrane (CM), in a catalytic ozonation membrane reactor (COMR) for municipal wastewater reclamation. The results demonstrated that CMO/CM and CMO/CN/CM used in the COMR exhibited high performance in terms of flux, removal efficiency of effluent organic matter (EfOM), control of disinfection by-products formation potential (DBPs-FP), and mitigation of membrane fouling. Notably, catalytic ozonation by CMO/CM showed superior reduction in DBPs formation (40.6 % of nitrogenous DBPs, 83.4 % of halogenated hydrocarbons, 36.6 % of haloacetic acids). Furthermore, significant inhibition of both organic fouling and biofouling was observed in the COMR. The addition of O3 altered the membrane fouling mechanism from gel layer formation to intermediate blocking. Ozonation primarily reduced the physically reversible fouling while catalytic ozonation additionally mitigated physically irreversible fouling. In addition to the almost complete removal of total cells and proteins, catalytic ozonation by CMO/CM further cleaned the α-polysaccharides and β-polysaccharides on the membrane surface, resulting in a 55.3 % reduction in biofilm thickness and demonstrating strong self-cleaning properties. These findings have important implications for enhancing the overall performance and durability of COMR systems in municipal wastewater reclamation.