Investigation of backwashing effectiveness in membrane bioreactor (MBR) based on different membrane fouling stages

Abstract

In this study the effect of different fouling stages of hollow fiber membranes on effective backwashing length in MBR has been investigated. Computational fluid dynamics (CFD) is imported to simulate backwashing process. A multi-physics coupling model for free porous media flow, convective mass transfer and diluted species transport was established. The laser bijection sensors (LBS) were imported to monitor the backwashing solution position inside fiber lumen. Simulation results indicated that membrane fouling degree could change the velocity of backwash solution inside fiber lumen and make a further effect on effective backwash length. The signal variations of LBS are in accordance with the simulation results. The backwashing process can only play an active role when the filtration pressure is below the critical TMP. It can be concluded that backwash duration in industrial applications need to be set based on changes in TMP.

Partial nitrification/ANAMMOX (PN/A) membrane aerated biofilm reactor (MABR) under a low C/N ratio and metagenomics identification

“…The sludge suspension concentration was obtained by the weighing method. 33 16S rRNA sequencing and metagenomics were used to analyze the microbial population structure based on Illumina high-throughput sequencing platforms according to prescribed methods. 16S rRNA sequencing mainly included the following steps.…”

Membrane processes

“…Cui, Wang, et al (2018) used CFD to simulate backwash in MBRs. Results indicated that the degree of membrane fouling changed the velocity of the backwash solution, affecting the optimum backwash length.…”

Optimal control of backwash scheduling for pumping energy saving: Application to the treatment of urban wastewater

“…An effective backwash strategy can delay irreversible fouling and reduce the overall cost associated with UF foulants [10][11][12]. Backwash duration and frequency are important parameters [13][14][15] that influence fouling and cannot be determined solely based on the supplier's recommendations [16]. Most MBR plants operate at a constant flux, and fouling is generally indicated by an increase in transmembrane pressure (TMP) over time.…”