Membrane scouring to control fouling under fluidization of non-adsorbing media for wastewater treatment

Abstract

Gas sparging is used as a traditional way to control membrane fouling in submerged membrane bioreactors (MBRs) in wastewater treatment. However, the gas sparging accounts for the largest fraction in operational cost to run the MBR systems. In this study, membrane fouling was controlled by integrating scouring media with gas sparging to reduce fouling rate at relatively low operational energy. Comparative study was performed using a fluidized membrane reactor treating synthetic feed solutions between polyethylene terephthalate (PET) scouring media (SM) fluidized by gas sparging (GS), liquid recirculation (LR), and combination of them to control membrane fouling. Addition of PET scouring media reduced the gas flow rate by 67% more with 30% less in fouling rate than gas sparing only. Combined usage of gas sparging and liquid recirculation to fluidize the PET scouring media (LR + GS + SM) showed 37% lower in fouling rate than that obtained by the scouring media fluidized by liquid recirculation (LR + SM) only through the reactor. The LR + GS + SM configuration reduced energy consumption by 90% more than that required by gas sparging alone. Mechanical cleaning driven by fluidizing PET scouring media could reduce membrane fouling due to removing deposit of inorganic particles from membrane surface effectively. However, the PET scouring media was not very effective to reduce membrane fouling caused by organic colloids which are expected to contribute pore fouling significantly.

The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

“…Extensive tests subsequently have been carried out [24,27,128,130,244,, especially in view of the potentially lower energy cost than that of bubbling [24,204] and suitability for the anaerobic MBR. Effects of treating different types of wastewater [258,259,261,262,276] (e.g., using municipal versus synthetic wastewater [24,258]), trace organics [128,278], membrane type [273] (including effects on membrane integrity [271,272,275]), screen size [259], fluidized media [236,244,279,280] (including size and packing amount [244,267,268,271,275]), operating conditions [260,271] such as temperature [260][261][262], scale [261], design [130,261,264,265,276] (e.g., single (AFMBR) versus two-stage (AFBR-AFMBR) systems [130]), which collectively proved the efficacy of GAC in scouring the membranes. Different embodiments of the AFMBR include single (AFMBR) versus two-stage (AFBR-AFMBR) systems …”

A review on anaerobic membrane bioreactors (AnMBRs) focused on modelling and control aspects

“…The use of gas scouring has been widely adopted to control membrane fouling, however this physical cleaning accounts for a significant term in energy demand for MBR technology (Aslam et al, 2017a). In this respect, much effort has been focused in the last years on optimizing gas sparging intensity in AnMBR technology ( It is expected that physical cleaning effectiveness will tend to decrease over time due to the accumulation of irreversible fouling on the membrane surface.…”

Microalgae-based biofuels, resource recovery and wastewater treatment: A pathway towards sustainable biorefinery

“…However, membrane fouling is a major issue in commercialization of this technology[102][103][104]. Overcoming membrane fouling is energy intensive and frequent chemical cleaning is required which results in reduced membrane lifetime and increased operating cost[105][106][107][108][109][110][111][112].…”