Pharmaceuticals in the Environment and Their Removal in Conventional Wastewater Treatment Plants

Pharmaceutical compounds in aquatic media have become an important environmental issue in recent decades, since they are biologically active substances and often resistant to biodegradation. Physicochemical properties, such as molecular formula (chemical composition), molecular weight, solubility, volatility, octanol–water partition coefficient (log Pow), and the protonation constant (pKa) values effect the concentration and the fate of the pharmaceuticals in the environment. The low concentration of these compounds and the complexity of the matrix make their analyses quite difficult. It is possible to determine the pharmaceuticals in all aqueous matrices, sediments, soils, and sewage sludge. The complete removal of these compounds is hardly possible in conventional wastewater treatment plants (WWTPs). The removal efficiency is dependent not only on their physicochemical properties, but also on the characteristics of WWTP influents. Tertiary treatment processes, such as advanced oxidation, membrane technologies, sand filters, and activated carbon adsorption systems are necessary to achieve a better treatment efficiency. It has been proved that pharmaceuticals have toxic effects on the organisms in all trophic levels even at very low concentrations. Therefore, their input to wastewater should be controlled and their complete removal should be strived for. In this chapter, the occurrence of pharmaceuticals in the environment and their analytical methods are given, and pharmaceutical removal efficiencies of various types of secondary and tertiary treatment plants are reviewed. Toxic risk assessment of pharmaceuticals for receiving water bodies is presented.