Monitoring and Removal of Organic Micro-contaminants by Combining Membrane Technologies with Advanced Oxidation Processes

In the last decades, the development of advanced analytical techniques has revealed the presence of micro-contaminants (MCs) in effluents from municipal wastewater treatment plants (MWTPs), which represents a significant challenge to wastewater reclamation as biological treatments attain only partial removal of MCs. The application of tertiary treatments for refining these waters so as to avoid MCs reaching both irrigation systems and water natural bodies is widely studied. In this chapter, an overview of the combination of different membranes with advanced oxidation processes and conventional physicochemical treatments for the improvement of MCs removal efficiency is assessed. In addition, membrane fouling effects, progress in analytical monitoring techniques and brief economic considerations have been also tackled. Pressure-driven membrane processes for MCs retention is discussed focusing microfiltration (MF)/ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), forward osmosis (FO) and membrane distillation (MD) systems. Reviewed physicochemical processes included adsorption on activated carbon; coagulation/flocculation and chlorination/ozonation also integrated with membranes processes. Membrane bioreactors integrated with other membrane systems as NF or RO showed high removal rates (99%) for all compounds looked over. Different advanced oxidation processes as pre-treatment stage for mainly avoiding fouling and as post-treatment of the membrane rejection stream is also discussed. Integration of membranes with photo-reactors by both photocatalytic membranes and hybrid systems coupling photocatalysis and membrane processes (for retaining the powdered TiO2 in the photoreactor) has been also addressed in this chapter. Economical and regulation considerations in different countries and EU are discussed as the final and conclusive section of this work.