Disinfection of treated wastewater : a comparative study on chlorine, ozone and ultraviolet irradiation

Abstract

This study investigates methods of disinfecting treated wastewater for reuse purposes. The main question that guides the research focuses towards selecting an alternative technology to the widespread and harmful use of chlorine in sewage treatment plants. Since chlorine is highly toxic, large gaseous chlorination systems such as the ones used locally, pose a health hazard to plant operators and are a potential risk to public health and the environment. The growing awareness of the health hazard and risks involved by using gaseous chlorine in wastewater treatment facilities has called for the implementation of strict regulations. Such requirements are consequently augmenting the need to invest in research aiming to identify alternative technologies that are less hazardous and perhaps more efficient. Research on var10us alternative disinfection options confirmed that ozone and ultraviolet irradiation are becoming increasingly popular. This study analyzes how these compare with chlorination and their viability within the local context. Research developments and improved techniques proved this possibility within the treatment process. It was established that ultraviolet irradiation is amongst the most suitable alternative. However, the research student revealed that this alternative also impose limitations in that being incapable to maintain residual in the distribution system and difficult to predict energy costs.