Trace organic contaminants removal by combined processes for wastewater reuse
The term trace organic contaminant (TrOC) refers to a diverse and expanding array of natural as well as anthropogenic substances including industrial chemicals, chemicals used in households, compounds and their metabolites excreted by people and by-products formed during wastewater and drinking-water treatment processes. Activated sludge-based processes (e.g. membrane bioreactor) are environmentally friendly approaches to wastewater treatment. However, conventional biological treatment alone may not be effective for all TrOCs that are known to occur in municipal and industrial wastewater. The low removal efficiency of biologically persistent and hydrophilic TrOCs necessitates the integration of MBR with other membrane-based and physicochemical processes to ensure adequate removal of TrOCs. Because MBRs can produce effluent with low turbidity and bulk organic content, significant synergy can be realised when it is integrated with other advanced treatment processes. In addition, given the small physical footprint of the MBR process, it is possible to deploy these integrated systems for decentralised water recycling applications. This chapter provides a brief overview of the integration of advanced treatment processes including activated carbon adsorption, advanced oxidation processes and high retention membranes (e.g. nanofiltration and reverse osmosis) with MBR for TrOC removal.