Drinking water and waste water disinfection: Strategies and problems

Within the European Union, many different disinfection systems are being used. They are applied both in facilities for the potabilization of ground and surface water, and for the disinfection of wastewater after a biological treatment. Although chemical and physical processes are usually employed, treatment procedures and results are quite different. In this work, main disinfection systems used in European Countries in water potabilization facilities are described. The growing use of surface water for the production of drinking water, underlines the necessity to minimize the formation of by-products with potentially toxic longterm effect. This leads to define adequate control strategies in potabilization processes: both used reagents and process schemes must be analysed considering this important aspect. In the second part of the paper, problems dealing with the disinfection of wastewater and the main characteristics of the most important disinfection systems (as far as their applicability and efficiency are concerned) are analyzed. The results of a research carried out in order to compare four different disinfection systems (ozonation, disinfection with chlorine dioxide, UV radiation, peracetic acid disinfection) are also shortly presented.