Titanium-based photocatalysis as the pretreatment for ultrafiltration of secondary municipal effluent with low concentration of organic matters

Abstract

Ultrafiltration (UF) has been regarded as a cost-effective option compared to NF and RO for the municipal effluent reclamation process. But the fouling caused by organic matter from the biologically treated sewage effluent is still a serious problem in the process. The photocatalysis was employed as the pretreatment measure for the ultrafiltration of secondary effluents. The fouling potential k was significantly lowered by this pretreatment measure. The effects of catalyst type (anatase, rutile, and Degussa P-25), catalyst dosage, pH value, and UV light intensity on fouling potential variation and dissolved organic carbon (DOC) removal were investigated. The results showed that the presence of UV and TiO 2 improved DOC removal ratio. The effect of photocatalyst type on fouling potential abatement was compared. The pH value and catalyst concentration were optimized to get the highest fouling potential reduction and DOC removal efficiency.

Organic fouling and floc transport in capillaries

“…It is therefore desirable to prevent -or at least minimize to the greatest extent possiblethe direct retention of NOM by the UF membranes. Thus before the UF the water is pretreated by titanium-based photocatalysis [12], ozonation [13], dissolved air flotation [14], granular filtration [15], or a combination of coagulation, flocculation and adsorption [16][17][18][19]. The last combination shows a good potential for reducing fouling and increasing NOM retention at the same time.…”