Abstract
Abstract
Most South African water treatment plants utilise surface water sources whose quality is continuously compromised due to high return flows and indirect reuse. The water treatment methods used by these plants are based on the removal of turbidity, various chemical contaminants and microorganisms. Recently introduced NOM regulations added the removal of natural organic matter (NOM) as a priority. Basic anion exchange resins can be used to remove NOM. This paper reports this method of NOM removal. Due to the variability in the composition of NOM in natural raw water, eight surface waters were collected throughout South Africa as representative of the different water types of the country. Two resins were used for this study, a strong and a weak – base anion resins. They were chosen for their availability and competitive price at the local market. NOM removal in raw water was quantified by measuring ultraviolet absorbance at a wavelength of 254 nm (UV 254), dissolved organic carbon (DOC) and by calculating the specific ultraviolet absorbance (SUVA) at 254 nm. The Freundlich equilibrium isotherms were also fitted and the Freundlich parameters determined.