Removal of natural organic matter (NOM) by ion exchange from surface water for drinking water production: a pilot-scale study

Natural organic matter (NOM) in drinking water causes esthetic concerns such as odor, taste, and color and is responsible for the disinfection byproducts formation during drinking water production. The goal of this study was to determine the efficiency of macroporous polyacrylic ion exchange resins for the removal of NOM as a function of empty bed contact time (EBCT), bed expansion, and regeneration procedure. Two resins were examined: the coarse Purolite((R))PPA860S and the fine Purofine((R))PFA860 resin. The tests showed that both resins are suitable for NOM removal. The reduction in particle size (beads of the fine resin were 18% smaller than those of the coarse one) of the fine resin had little effect on NOM removal, although the exchange capacity of the fine resin after regeneration was 12% higher than that of the coarse resin after multiple regenerations. The influence of (due to the re-use of the regenerating solution) was examined on the basis of a regeneration solution with only. The test results showed no reduction in NOM removal during prolonged operation. Finally, it was concluded that the EBCT can be significantly reduced as increasing the flow velocity from 15 to 20m/h did not result in a significant reduction in NOM removal efficiency.