Over the past few years, the occurrence of pharmaceutical residues in the environment has attracted great interest regarding the possible harmful effects of many of these pollutants to living organisms. One of the main sources of pharmaceuticals in the environment is the discharge of effluents from wastewater treatment plants (WWTPs), where their removal is often incomplete. Natural wastewater treatment systems such as constructed wetlands constitute a relevant option to conventional methods due to their efficiency, low establishment costs and reduced operation and management requirements. This book discusses processes involved with wastewater treatment as well as management strategies and their impact on the environment.