Environmental and economic sustainability of ion exchange drinking water treatment for organics removal

Water treatment infrastructure faces numerous operational and financial challenges in most regions of the world. Ion exchange is a water treatment technology that can be used to remove various contaminants in drinking water and has shown increased adoption in recent years due to its operational advantages; however, limited research has been conducted on the environmental and economic sustainability of ion exchange systems. This study utilizes life cycle assessment and cost analysis to holistically evaluate environmental and economic impacts of ion exchange technology that is used for reduction of disinfection by-products via organics removal in eight drinking water treatment plants in Florida. A functional unit accounting for both water quantity and quality was used and showed to have a significant effect on the evaluation results. Impact assessment results show that the construction phase has negligible environmental impact in comparison to the operation phase. Systems that use fixed bed reactors with conventional resin were compared with systems using completely mixed flow reactors with magnetic ion exchange resin. Fixed bed systems evaluated have higher salt usage and brine waste production, but use less electricity, resin, and require less transport of materials. This tradeoff causes fixed bed systems to have a higher environmental impact in categories of eutrophication, carcinogenics, non-carcinogenics, and ecotoxicity but lower impact in other categories. Furthermore, it causes fixed bed systems to have a lower operation cost compared with completely mixed systems. Results also show that both environmental impacts and operation costs per functional unit decrease with scale, similar to economies of scale effects.