Comparaison technico-économique de solutions alternatives pour l'abattement des précurseurs de sous-produits organochlorés dans les eaux de surface du Canada

Chlorine is widely used in the North American water industry for both primary and secondary disinfection. This disinfectant can efficiently inactivate a broad range of pathogens such as viruses at low cost, while providing a measurable residual concentration in distribution systems. However, free chlorine reacts with natural organic matter (NOM) and generates potentially carcinogenic disinfection by-products (DBP). As regulations recently became stricter in the province of Quebec, many utilities using chlorine as secondary disinfectant are reviewing their DBP control strategy to achieve regulatory compliance. The purpose of this project was (i) to evaluate the DBP precursor removal efficiency of six processes, namely alum and ferric sulfate (FS) coagulation, intermediate ozonation (IO3), recirculated powdered activated carbon (PAC), magnetic ion exchange (IX) and spiral-wound nanofiltration, (ii) to assess the impact of source water quality on process performance using six Canadian surface waters representing a broad range of characteristics and (iii) to evaluate the capital investment and operation and maintenance costs of each technology in order to compare the performance of the investigated processes on the grounds of both treatment performance and costs.