Alternative Regeneration of Combined Ion Exchange Resins with K+ and HCO3-
- 1. Alternative Regeneration of Combined Ion Exchange Resins with K+ and HCO3- Future Ion Exchange Treatment Plant Improved Waste Stream Current IX Residual Disposal Options Ion Exchange... ...is a robust water treatment process... HCO3 - Surface Discharge - Inland discharge more viable 5% Y Reduced impact to K+ X+ envionment TDS: 1,000 – 15,000 mg/L Benefits Biodegradation Coagulation pretreatment Less volume generated from Improved kinetics use of combined ion exchange Improved removal Regeneration Less harmful anions/cations NO3, ClO4, BrO3 from alternative regeneration Membrane pretreatment Wastewater Discharge Beneficial reuse Internal regenerant reuse Lessen impact on biological Reduced TDS HCO3- used in nitrification KHCO3 2+ 2+ Stand alone: Ca /Mg , NOM, Outcome Brine NO3-, BrO3-, ClO4- Regenerant cost ↑ but, Land Application Disposal cost ↓ Fertilize with K+ ...with a waste stream that can be managed sustainably Environmental impact ↓ Inland disposal Public health ↑ This research was funded by Environmental Engineers of the Future funding program to GM and faculty start- up funds from THB. Gabe Maul (M.E., 2013) Dr. Treavor H. Boyer Overview and Objectives Water treatment with ion exchange requires the production of concentrated NaCl solution for regeneration that poses a significant risk to the environment. Increasingly stringent regulations on regenerant disposal can make the entire ion exchange process cost prohibitive. Alternative regeneration, the use of regeneration solutions that are more environmentally benign than NaCl, has the potential to significantly improve the sustainability of ion exchange. Combined ion exchange, the idea of using both cation and anion exchange resins simultaneously, has recently emerged offering synergistic benefits in both treatment and regeneration. Although several applied studies have compared NaCl and an alternative regenerant, a fundamental understanding of ion exchange interactions for a wide range of ion exchange resins and contaminants is still lacking, and very few studies have investigated regeneration of combined ion exchange. The goal of this research is to provide improved understanding of ion exchange interactions with alternative regenerants and combined ion exchange. The specific objectives of this research are (1) compare regeneration effectiveness of NaCl to alternative regenerants KCl, NaHCO 3, and KHCO3 using several pairs of ion exchange resins saturated with different pairs of contaminants, (2) compare treatment effectiveness of different pairs of contaminants using several resin pairs saturated with NaCl and alternative regenerants KCl, NaHCO3, and KHCO3, (3) compare economic, environmental, and social advantages and disadvantages of alternative regenerants. Preliminary Conclusions K+ regenerated C-100 resin acts similarly as Na+ regenerated resin. For the Ca2+/NO3- resin pair at a resin dose based on equivalent regeneration capacities, a regenerant concentration ratio of 100× resin capacity was high enough to completely regenerate NO3- resin but only able to regenerate Ca2+ resin to 70% of capacity. Download poster Treavor H. Boyer, Ph.D. ~ Assistant Professor ~ Department of Environmental Engineering Sciences ~ University of Florida [email protected] ~ 352.846.3351 ~ www.ees.ufl.edu/homepp/boyer ~ www.twitter.com/WaterWeUpTo