Natural Dissolved Organic Matter Removal and Subsequent Disinfection By-Product Formation: A Comparison of Ion Exchange and Activated Carbon

摘要

A weak base ion exchange resin and a granular activated carbon (GAC) were compared for their ability to sorb natural dissolved organic matter (DOM) and reduce specific ultra violet absorbance (SUVA). Disinfection byproduct formation of water having high bromide content after separate ion exchange and carbon adsorption and subsequent chlorination was compared. The ion exchange resin showed superior dissolved organic carbon (DOC) uptake, although SUVA reduction by the two sorbents was comparable. The concentrations of total trihalomethanes (THM4) and the sum of six haloacetic acids (HAA6) were reduced by both sorbents, although the resin was capable of meeting drinking water regulations at much lower doses. The effect of ion exchange and carbon adsorption on THM4 reactivity (yield) was markedly different, and the results demonstrate that ion exchange removes reactive DOM species that GAC does not. Bromine incorporation factor (BIF) values for both sorbents increased initially and were similar at low dosages; however, as dosage increased further the BIF after resin treatment decreased rapidly and remained significantly lower than the BIF after GAC treatment.