Arsenic waste from water treatment systems: characteristics, treatments and its disposal
As with other water treatment systems, arsenic treatment creates not only quality water but arsenic waste as well. Management of arsenic waste is now becoming a major public concern due to its harmful effects on the surrounding environment, including serious health problems such as skin cancers and various internal carcinomas. The main aim of this paper is to review: (i) the characteristics of arsenic waste produced by arsenic treatment systems; and (ii) the treatment and disposal methods of this waste. Arsenic waste type or its characteristics play an important role in choosing the best method of treatment and disposal. Currently, encapsulation of arsenic waste through solidification/stabilization (S/S) techniques is considered to be the most attractive solution and this method is the focus of this review. A number of studies have used cement by itself and in combination with additives such as lime, iron, silicates, or fly ash in the S/S process. Although there is a lack of systematic investigations and differing procedures for testing the effectiveness of the treatment methods, it was agreed that incorporating additives could increase the effectiveness of the S/S process depending on the type and dose of additives.