Pilot Scale Comparison of Enhanced Coagulation with Magnetic Resin Plus Coagulation Systems

Abstract

Previous work has shown that magnetic ion-exchange treatment before coagulation gives high natural organic matter (NOM) removal and reduced levels of disinfection byproduct when compared to conventional enhanced coagulation. The impact of the resin process on the downstream floc formation process after coagulation and the subsequent effect on clarification has not previously been shown. Water containing high concentrations of NOM were treated at pilot scale using (1) conventional enhanced coagulation and compared with (2) treatment using magnetic resin followed by coagulation at reduced doses of 50-70%. Bench scale testing was also carried out to determine floc properties for systems with and without resin pretreatment It was demonstrated that pretreatment using magnetic resin was able to significantly reduce the turbidity load onto filters as a result of the formation of a large and more robust floc. Resin pretreatment also improved NOM removal and reduced disinfection byproduct formation when compared with conventional coagulation. The turbidity load on to the filters following resin pretreatment was 1.5 +/- 0.7 NTU, whereas this value was 2.9 +/- 0.3 NTU for conventional coagulation. Flocs produced with resin pretreatment were larger than those produced by conventional coagulation, with a median floc size of 1000 microm compared to 600 microm. The improvement in floc properties following magnetic resin pretreatment was proposed to be due to the removal of NOM thatwas characteristic of carboxylic acids before the coagulation stage.

Pre-treatment of surface waters for ceramic microfiltration

“…Subsequently, clarification followed by SIX was found to yield very low residual organics concentrations (Fig. 3d), in keeping with previously reported findings (Fearing et al 2004;Jarvis et al 2008;Humbert et al 2007;Fan et al 2008;Singer and Bilyk, 2002).…”

Probing the application of a zirconium coagulant in a coagulation–ultrafiltration process: observations on organics removal and membrane fouling

“…Hussain et al indicated that zirconium tetrachloride was more effective for the removal of low-medium molecular weight organics, which could limit the formation of disinfection byproducts (DBPs) oen known to be carcinogenic. 12,13 Besides, Zr salt was also conrmed to be effective for arsenic removal, 14 and in the treatment of paper and pulp wastewater. 15 What also worth to be noticed is organic membrane fouling, since it hinders the widespread application of membrane techniques during surface water treatment.…”

Fouling of anion exchange resin by fluorescence analysis in advanced treatment of municipal wastewaters

“…Anion exchange resin (AER) is an important adsorbent in water purification to remove anionic pollutants (Bolto et al, 2002;Boyer et al, 2008;Higgins, 1973;Huang et al, 2012;Jarvis et al, 2008). However, the application of AERs has been limited for many years because of capacity loss after regeneration and the increasing volume of desorption concentrate, both of which are attributed to the resin fouling (Abrams, 1982).…”