Choosing the most appropriate technique for wastewater disinfection – parallel investigation of four disinfection systems with different preceding treatment processes

Abstract

A variety of bacterial, viral and parasitic pathogens are transmitted via water. Adequate disinfection of wastewater is therefore vital to address the potential health risks of water reuse. A range of well-established methods is available for wastewater disinfection. The selection of the most appropriate technology plays a key role in enhancing the safety, acceptability and reliability of water reuse systems. The objective of this study was the parallel examination of well-established and emerging wastewater disinfection methods, with particular attention being paid to the preceding wastewater treatment processes. The disinfectants investigated were: ultraviolet (UV) radiation, ozone (O3), chlorine dioxide (ClO2) and electrolytically-produced chlorine gas (Cl2). In order to support the specific selection of the most appropriate disinfection method, multiple criteria were determined: concentrations of indicator organisms, effluent toxicity, microbiological stability of the effluent, costs, energy consumption, and supplementary effects. The results show that stringent hygienic treatment objectives can be met with each of the applied methods immediately after disinfection, while the results of the evaluation of the further criteria differ widely between the analysed disinfectants.