Comparison between rejection characteristics of natural organic matter and inorganic salts in ultra low pressure nanofiltration for drinking water production

Abstract

Comparisons between rejection characteristics of natural organic matter and inorganic salts by nanofiltration in a very low operational pressure (<0.5 MPa) are demonstrated here. A nanofiltration pilot plant has been operated at the Tamagawa water purification plant, which is located downstream on the Tama River, Japan. The molecular weight distribution and concentration of natural organic matter that account for trihalomethane formation potential, and concentrations of various inorganic salts have been measured in the raw water from the Tama River, microfiltration pretreated effluent and nanofiltration production during 6-months operation of the pilot plant. This paper discusses the water quality and rejection mechanism of natural organic matter and inorganic salts. In addition, the steric-hindrance pore (SHP) model and the Nernst-Planck equation have been used to evaluate membrane pore structures and rejection of ionic solutes, respectively.

Inorganic fouling of pressure-driven membrane processes — A critical review

“…Most of the membranes are composed of organic polymers, such as aromatic polyamide, polysulphonates, polyvinyl alcohol, piperazineamide, polyimide, and polyacetylene [10,11]. Table 2 shows some of the commercially available membranes.…”

Influence of feed water chemistry on the removal of ionisable and neutral trace organics by a loose nanofiltration membrane

“…However, removal of these compounds during conventional biological sewage treatment varies greatly, ranging from almost no removal (for some compounds such as carbamazepine) to nearly complete removal (Ternes, et al 2004). Membrane filtration such as NF and RO can act as a very reliable barrier for the removal of pathogenic agents and an array of inorganic contaminants (Ratanatamskul, et al 1998, Thanuttamavong, et al 2001. The efficiency of NF and RO processes with respect to trace organic contaminant removal has been extensively investigated (Verliefde, et al 2007, Van der Bruggen, et al 2006.…”

Formation of organic deposits on low-preassure reverse osmotic membranes in treating water from surface sources

“…13, b) water demonstrates that, during the bench operation, it is high-molecular compounds that are primarily adsorbed from water. The general picture of membrane pollu- tion can vary when other substances are concurrently formed on the membrane, including poorly soluble salts (calcium carbonate), colloidal and organic substances, colloids of iron hydroxide and other membrane sediments [29][30][31][32][33][34][35][36][37][38]. Fig.…”

“…Publications devoted to the formation of organic contaminants on reverse osmosis membranes have thus far reported conflicting opinions [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. On the one hand, enormous practical experience has been accumulated in application of reverse osmosis and nanofiltration systems for the treatment of surface and groundwater for drinking and industrial water supply [7,[8][9][10][11][12][13][14][15][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. On the other hand, a number of authors have argued that dissolved organic contaminants should be removed from the water entering the reverse osmosis plants at the pre-treatment stage.…”