Investigation of pre-coagulation and powder activate carbon adsorption on ultrafiltration membrane fouling

Abstract

a b s t r a c tPre-coagulation by alum before ultrafiltration without (CUF) and with (CAUF) powdered activated carbon (PAC) addition was investigated to explore the influence of PAC on membrane fouling. It was found that the continuous addition of a low dosage of PAC reduced membrane fouling for operational run periods o20 days, both for reversible and for irreversible components of fouling. The presence of PAC increased the removal of dissolved organic matter (DOM), particularly proteinaceous substances, and some fractions of humic-type substances. For a longer operation time (420 days) an increase in mainly reversible fouling was evident and was attributed to microorganism growth in the cake layer, as indicated by the enhanced concentrations of extracellular polymeric substances, such as polysaccharides and proteins. A process of crystallization of the coagulant floc in the cake layer with increasing operation time was believed to cause desorption of DOM from primary coagulation particles and a decrease in their size, and consequently a higher density of cake layer. PAC absorption of desorbed DOM within the cake layer, and residual DOM after coagulation, reduced DOM reaching the membrane surface and the extent of subsequent internal membrane fouling.Crown

Performance of an integrated granular media – Ultrafiltration membrane process for drinking water treatment

“…The MW distributions obtained from the chromatograms displayed significant differences in the feed and effluent samples (there was little difference between tank samples and effluent samples), particularly in the range of large molecules identified as biopolymers. As previously reported, part of the EPS can be removed by the coagulation process [42]. However, the residual EPS was higher in the CUF tank than that in CSUF tank.…”

Effect of pre-coagulation using different aluminium species on crystallization of cake layer and membrane fouling

“…Different types of pre-treatment before membrane filtration have been explored for many years, such as adsorption, coagulation, and oxidation. [1][2][3][4] Some materials, such as powdered activated carbon (PAC), 5 heated aluminum oxide particles (HAOPs), 6,7 magnetic ion exchange (MIEX) 8 and synthesized zeolite, 9 have been studied as pre-adsorption materials to mitigate membrane fouling. An anion exchange resin before ultrafiltration can also significantly mitigate irreversible fouling and reduce the dissolved organic carbon (DOC) content of clarified water.…”

Deposition of powdered activated carbon (PAC) on ultrafiltration (UF) membrane surface: influencing factors and mechanisms

“…Although there are many bench-and pilot-scale studies of the PAC/UF hybrid process [4][5][6][7][8], there are no full-scale applications [2]. The main reason for this plight is that PAC is in contact with the membrane in the PAC/UF hybrid process, but PAC is not tailor-made to match the requirements of UF operation; thus, the contact between the PAC and the membrane possibly undermines the performance of UF [2].…”