AWWA ACE70475

This powerpoint presentation begins by providing bulleted points of the presentation's content that includes the following: NO₃^-, ClO₄^-, HAsO₄^2- easily removed by chloride IX w SBA; separate target ion from background ions, then regenerate/replace resin; IX run length, peaking, and regenerability depend on affinity, K_ij or ? _ij, of ion for resin; matrices: Sty-DVB and Polyacrylic-DVB; functional groups: quaternary ammonium Trimethyl, dimethylethanol (std. resins) Triethyl, tripropyl, tributyl (selective resins); less-preferred ions peak: C_i,Eff > C_i,In; peaking eliminated with selective resins; divalent selectivity: HCO₃^- * CO₃2^- + H⁺; highly preferred ions^1- hard to regenerate; and, natural selectivity reversal in for ions^y, easy regeneration and direct reuse of spent regenerant. Presentation conclusions indicate that: affinity of ions for resins, K_ij,?_ij, determine run length, peaking, and regenerability; all but most preferred contaminants are subject to peaking; NO₃^-, ClO₄^- peaking eliminated - increase charge separation distance, and increase hydrophobic nature; divalent preference promotes deprotonation of polyprotic anions and pH waves in anion columns; for divalent/monovalent--HAsO₄^2-/Cl^--- exchange, selectivity reversal occurs and direct reuse of brine is possible without removing the arsenic; in absence of selectivity reversal, removal of contaminant--NO₃ ^-, ClO₄ ^---from brine before reuse is necessary. Includes table, figure.