Ozone-bromide interactions with NOM separated by XAD-8 resin and UF/RO membrane methods

Ozone-bromide interactions in the presence of selectively isolated natural organic matter (NOM) fractions were studied under batch conditions. XAD- 8 resin and ultrafiltration and reverse osmosis (UF/RO) membrane isolation methods were used for concentration of NOM from the Teays Aquifer, Champaign, IL. Experimental results show that both decomposition rates of aqueous ozone and disinfection by-product (DBP) formation are the functions of raw water characteristics, treatment process parameters, NOM isolate molecular weights, and isolation procedures. Bromate (Br03 -) formation is favored at high pH, high ozone dosage, and high initial bromide concentrations, but low dissolved organic carbon (DOC) levels. On the other hand, total organic bromine (TOBr) formation is favored at low pH, high bromide levels, and high 03'DOC ratios. The addition of alkalinity promotes Br03 - formation. An inhibitory effect on bromate formation is observed upon ammonia addition. The addition of hydrogen peroxide increases bromate formation for membrane isolates, while TOBr production is significantly reduced. Finally, the highest bromate yields are associated with NOM isolated by the XAD-8 resin technique, whereas the highest TOBr yields are found with the RO isolate.