Effect of coagulation mechanism on membrane permeability in coagulation-assisted microfiltration for spent filter backwash water recycling

Experimental determination of the characteristics of physico-chemical particles in air-scouring-membrane (microfiltration) backwash water produced during drinking water treatment

“…In addition, Lee et al (2000) showed that membrane permeability with CN was superior to that with SF. Huang et al (2011) reported that pre-coagulation mechanisms govern the membrane flux of subsequent microfiltration steps, and that the most efficient membrane flux is induced by PCN conditions.…”

“…Filtration processes using sand, anthracite, polymer membranes, and ceramic membranes have been emphasized in particular as the last barriers for separating solids from a liquid. Because chlorine disinfection usually occurs just after filtration, and the final produced water is supplied directly to the consumer, it is difficult to supplement the treatment system with an additional solid/liquid separation process for have performed air-scouring backwash to clean up the fouled membrane more effectively to extend membrane operation time (Katsuki et al, 2008;Pikkarainen et al, 2004;Peiris et al, 2013;Huang et al, 2011). Pre-coagulation before membrane filtration (MF/UF) was introduced to enhance the removal of total organic carbon (TOC) and taste/odor matter rather than to improve performance through reduction of fouling (Katsuki et al, 2008).…”

Application of a Low Cost Ceramic Filter for Recycling Sand Filter Backwash Water

“…The initial flux at this pressure was measured to be approximately 1000 L/m 2 /d and remained constant until day 14. In Run-3, the TMP was further increased to 3.0 kPa and operated continuously for 5 days (days [15][16][17][18][19] 2 and 3), and <0.1 mg/L (except day 2), respectively, which were approximately 99.4% of the average removal from the raw SFBW. In Run-2, feed water turbidity, Fe, and Mn were measured as 319-770 NTU, 14-78.5 mg/L, and 2.4-10.15 mg/L, respectively.…”

“…Therefore, the complete pore-blocking model most appropriately describes the mechanism of flux decline in the present study. Huang et al [16] studied various resistances to filtration in a coagulation/filtration process. They observed that cake resistance (due to filtration cake formation) plays an important role in membrane filtration if coupled with coagulation, and pore blocking is negligible as the majority of particles are larger than a nominal size of membrane.…”

“…Alum-based coagulants such as aluminum sulfate (Al 2 (SO 4 ) 3 ) are generally used as cost-effective coagulants in the coagulation and flocculation process. The consistency of the filtration flux largely depends on the size and structure of the flocculants formation, which eventually dependson the operating conditions such as pH and coagulant dosages [14][15][16]. For alum coagulation, size and structure of the flocculants are induced by various hydrolyzing Al species [17].…”