Removal of Pharmaceuticals from Wastewater by Membrane Bioreactors: Factors, Mechanisms, and Perspectives

This chapter reviews the performance of membrane bioreactors (MBR) for the removal of pharmaceuticals from wastewater. Many factors affect pharmaceuticals removal by MBR. The factors include physicochemical characteristics of the pharmaceuticals and MBR o

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Contents 1 Introduction 2 Pharmaceuticals Removal by MBR 3 Factors and Mechanisms Affecting Pharmaceuticals Removal by MBR 3.1 Characteristics of the Pharmaceuticals 3.2 Operating Parameters 4 Bioaugmented MBR for Pharmaceutical Removal 5 Conclusion and Perspective References

Abstract This chapter reviews the performance of membrane bioreactors (MBR) for the removal of pharmaceuticals from wastewater. Many factors affect pharmaceuticals removal by MBR. The factors include physicochemical characteristics of the pharmaceuticals and MBR operational parameters. The presence of a membrane allows various adsorption mechanisms for pharmaceuticals. Conceptually MBRs can deliver better removal of pharmaceuticals than conventional activated sludge (CAS) processes because of operation under longer solids retention times (SRTs), higher mixed liquor suspended solids (MLSS) concentrations, and complete retention of suspended solids. However, the available reports from lab and full-scale plants are sometimes conflicting. Further work is required to improve our understanding of the overall fate and degradation pathways of pharmaceuticals in MBRs. Keywords Membrane bioreactor, Pharmaceuticals, Biodegradation, Adsorption, Sludge retention time

F. I. Hai (*) and W. E. Price Strategic Water Infrastructure Laboratory, The University of Wollongong, Wollongong, NSW, Australia e-mail: [email protected]; [email protected] Sara Rodriguez-Mozaz, Paqui Blánquez Cano, and Montserrat Sarrà Adroguer (eds.), Removal and Degradation of Pharmaceutically Active Compounds in Wastewater Treatment, Hdb Env Chem, DOI 10.1007/698_2020_676, © Springer Nature Switzerland AG 2020

F. I. Hai and W. E. Price

1 Introduction The conventional wastewater treatment plants were not designed to remove emerging contaminants such as pharmaceuticals. The ineffective removal of pharmaceuticals from wastewater is a significant concern because pharmaceuticals are biologically active and can present detrimental effects to the aquatic environment. The effects include acute and chronic toxicity to aquatic organisms, accumulation in the ecosystem, and various adverse effects on human health [1]. Membrane bioreactors (MBR) are an advancement over the conventional activated sludge processes. It combines biodegradation and membrane separation in a single step. Details on the basic principle, design, and operation of MBRs are available elsewhere [2]. This chapter provides a brief overview of the factors and mechanisms of pharmaceuticals removal by MBR.

2 Pharmaceuticals Removal by MBR Compared to the conventional activated sludge (CAS) processes, MBRs can operate under longer solids retention times (SRTs), higher mixed liquor suspended solids (MLSS) concentration, and complete retention of suspended solids. Hai et al. [3] noted that MBRs may offer additional removal mechanisms for pharmaceuticals as follows: (1) the membrane is an effective barrier to solids, onto which pharmaceuticals may adsorb [4–6]; (2) pharmaceuticals may also adsorb on membrane surface [7]; and (3) the l