From natural habitats to successful application - Role of halophytes in the treatment of saline wastewater in constructed wetlands with a focus on Latin America

In many parts of the world wastewater is not treated at all or only to a limited extend because there are no resources available to establish an efficient wastewater treatment plant and there are also insufficient resources for operation and maintenance costs. Constructed wetlands (CWs) are nature-based solutions to treat wastewater in a highly cost-efficient manner. They can be very efficient and effective when well designed and maintained. Latin America is rich in saline natural wetlands. These can be used as prototypes for CWs treating saline process or wastewater. Similar to natural saline wetlands CWs can deliver several ecosystem services. This review focuses on saline wetlands and will first present the protagonists, the salt-tolerant plant species belonging to the halo- phytes with respect to their physiological and biochemical functions in wetlands. In a second step, their reme- diating activities which are used in many ways by local people will be shown in an exemplary manner. A number of CWs established in different regions, including Latin America, will be introduced as case studies. Halophytes are already being used in a number of CWs as biofilter but their usage could be increased, for example to treat aquaculture effluents and the biomass has a high potential for valuable compounds (i.e. metabolites) or for bioenergy production. Lastly, aspects of sustainability and ecosystem services of saline natural and constructed wetlands are shown with an emphasis on charting a way forward for the future holistic implementation of saline systems in Latin America.