Controlling of irreversible fouling and mechanism in a hybrid ceramic membrane bioreactor (CMBR)-reverse osmosis (RO) process for textile wastewater reclamation

Abstract

In this study, the fouling propensity of a hybrid ceramic membrane bioreactor (CMBR)-reverse osmosis (RO) process was investigated over a prolonged period using real textile wastewater effluent. Additionally, the effectiveness of in-situ ozonation for fouling mitigation was investigated. The results revealed that the CMBR-RO system achieved approximately 99.8 % removal of chemical oxygen demand and 97.4 % removal of total nitrogen. Despite this, soluble extracellular polymeric substances, particularly biopolymers and humics-like substances, remained in the system, resulting in irreversible fouling on the ultrafiltration (UF) membrane. The implementation of in-situ ozonation notably reduced ceramic membrane fouling by enhancing the filterability of larger macromolecules and eliminating inorganic/organic foulants from the membrane surface. Multiple modified fouling indexes were also utilized to evaluate the fouling potential of the RO feed water through size fractionation. It is worth noting that ozonation could pose a potential risk for subsequent RO membrane fouling due to the formation of low molecular weight neutrals, acids, and calcium- or silica- related inorganic-organic complexes. Overall, the integrated CMBR-RO system with in-situ ozonation exhibited excellent performance in producing clean water, achieving nearly 100 % removal of 20 Aromatic Amines. These findings underscore the viability of the CMBR-RO system as a practical and sustainable choice for the reclamation of textile wastewater.