Chapter 20 - Strategies to remove pharmaceutical residues from seawater

Abstract

There is abundant evidence on the occurrence of pharmaceutical residues in seawater. Even when these pollutants are dispersed in a huge mass of water, dilution is not fully achieved and thus quantifiable concentrations (ngL−1) of antiinflammatory, antibiotics, antidepressants, and other drugs have been reported in the Mediterranean Sea, the Bohai Sea, and the Baltic Sea. Different to that happening in freshwater bodies, the removal of pharmaceutical residues in seawater is not a priority, since other important pollution problems, like garbage, oil spills, and nutrients have captured the attention of environmentalists, NGO, policy makers, and most of the scientific community. Due to this, very few efforts are made to recognize, reduce, and remove pharmaceutical residues in coastal and seawater. In this chapter, wastewater discharges and brine are recognized as the main sources of pharmaceutical residues in the marine environment. Three strategies to reduce the loads of pharmaceuticals discharged into the sea are explored: (a) water reuse schemes in coastal urbanizations, (b) the implementation of zero-liquid discharge regimes in membrane-based and thermal-based desalination processes, and (c) the implementation or tertiary treatment systems based on advanced oxidation processes to remove pharmaceutical residues from wastewater and brine prior to dispose of them into the sea. The role of international legislation to lessen the volume of wastewater discharged into the sea is explored through the most recent amendment of the MARPOL Annex IV document, aimed to protect the water quality of the Baltic Sea.