The use of granular activated carbon for the treatment of impounded surface water

Increased levels of nutrients and pollutants are expected in the Inanda Dam (KwaZulu Natal, South Africa) as a result of wastewater effluent discharge, informal settlements and agricultural runoff in the catchment. Contaminants of atrazine and 2-methyl isoborneol were dosed into the feed water of a granular activated carbon (GAC) pilot plant to assess the performance of different process options for the treatment of Inanda Dam water. It was found that the use of ozonation and GAC did not result in increased levels of biological activity as expected. The use of ozone in conjunction with GAC is however recommended as significant benefit was obtained in the reduction of UV absorbance, chlorine demand and concentrations of other microcontaminants.