Magnetic ion exchange resin for reducing disinfection byproducts in drinking water: Pilot-scale study and organic matter characterization

Disinfection is an essential step in drinking water treatment to prevent waterborne illnesses. However, reaction of disinfectants with organic matter in the water can produce carcinogenic disinfection byproducts (DBPs), including trihalomethanes (THMs) and haloacetic acids (HAAs). Magnetic ion exchange (MIEX) resin has been used as a pretreatment to remove organics and reduce DBPs. In this study, a pilot-scale water treatment plant in Birmingham, AL (USA) that employed MIEX as a pretreatment to the conventional pilot treatment train was compared against an adjacent full-scale train that did not use MIEX. THM and HAA formation was tested via simulated distribution system (SDS) testing, and changes in organic character were assessed using fluorescence spectroscopy. MIEX treatment provided 20 % and 25 % removal of THMs and HAAs, respectively, compared to the full-scale treatment under typical SDS conditions. With higher residence times and incubation temperatures (15 days at 35 degrees C), MIEX treatment reduced HAAs by 36 %. Parallel factor (PARAFAC) analysis revealed that MIEX treatment reduced loadings for a terrestrial humic-like component. Additionally, MIEX treatment resulted in secondary benefits, including a reduction in the coagulant feed rate and a more stable pH and chlorine residual in the MIEX-treated water compared to full-scale treatment.

Automated summary

Disinfection is crucial in water treatment to prevent waterborne illnesses, but it can lead to the formation of carcinogenic disinfection byproducts. The use of magnetic ion exchange resin (MIEX) as a pretreatment has shown to effectively remove organics and reduce these byproducts. A pilot-scale water treatment plant employing MIEX treatment was compared to a full-scale treatment without MIEX. The results showed significant reduction in the formation of THMs and HAAs with MIEX treatment, as well as additional benefits.