Abstract
Global population growth induces increased threat on drinking water resources. One way to address this environmental issue is to reuse water from wastewater treatment plant (WWTP). However, the presence of pathogenic microorganisms and potentially toxic organic micropollutants does not allow a direct reuse of urban effluents. Membrane processes such RO or NF can be considered to effectively eliminate these pollutants. However, the integration of membrane processes involves the production of concentrated retentates which require to be disposed. To date, no treatment is set up to manage safely this pollution. This thesis project focuses on the application of ozonation for the treatment of NF retentates in the framework of the wastewater reuse. Ozonation is a powerful oxidation process able to react and degrade a wide range of organic pollutants. Four pharmaceutical micropollutants frequently detected in wastewater, were selected as target molecules. This study highlighted that NF can represent a viable alternative to the commonly used reverse osmosis process ensuring high retention at much lower operating costs. Ozonation appear to be effective to degrade the most reactive pollutants toward molecular ozone. However, this method is limited for the reduction of refractory ozone pollutants due to the inhibition of the radical chain by the high content of organic matter in the retentates. Finally, the ozonation processe appear to be a promising NF retentate treatment and further processing downstream of ozonation should allow reuse of treated retentates and lead to the emergence of a zero liquid discharge treatment scheme.