Municipal effluent disinfection by Iron Electrocoagulation

Abstract

In a global context of ever increasing population, climate change, and freshwater quality deterioration, water reclamation presents itself as a valid and valuable supplier of the resource. However, sewage and treated effluents remain important sources for waterborne pathogens, including Antibiotic Resistant Bacteria (ARB), a global emerging threat with potential to cripple our health systems and make us vulnerable once again to simple infections. Effluent disinfection thus becomes paramount to ensure suitable microbiological water quality and reuse applicability, although other water quality parameters critical for reuse applications (i.e. solid content, nutrients and organic matter) should also be addressed. Technologies developed for drinking water disinfection, such as chlorination, UV-irradiation, or ozone, usually fail to satisfy reclamation standards across all microbial groups, are not designed for nutrient or solid removal, and are known sources of hazardous disinfection by-products (DBPs). This research looks into a rather unknown water treatment technology, Iron Electrocoagulation (Fe-EC), as a suitable candidate for municipal effluent reclamation, based on its inactivation efficacy of a wide range of microorganisms, nutrient and solid removal, and absence of DBPs. The disinfection of ARB by Fe-EC and other processes is also described in detail, especially due to the shortage of literature regarding their inactivation, their general absence in water quality standards, and the health risk they pose to users. Significant efforts were made as to understand if indeed ARB are more resistant than other faecal indicator bacteria (FIB) when it comes to wastewater treatment, and if disinfection of both groups can be correlated...