[en] Spurred by the needs to find a better treatment method for wastewater, a method that is cheap, less complex when compared to conventional methods, and more importantly, that is climate friendly and has low cost of maintenance and operations, the use of constructed wetlands that is well designed, optimally operated, and of the best type of configuration has been proven by environmental scientists to meet these objectives. Constructed wetlands have proven to be very useful for the simultaneous elimination of nitrogen and organic matter as well as the removal of solids and pathogens contained in wastewater; it can achieve an efficiency as high as 70-94% NH4+removal, 70-96% N removal, 80-95% BOD and 73-96% COD removal. In this study, a profound review is made of the broad treatment process of wastewater from the primary treatment to the tertiary treatment, with the use of the conventional methods, analysis of constructed wetlands, its components, types and functions of each components, the various types of macrophytes and in their best operating environment, as well as the types of micro-organisms present. Also, a special focus is made about the characterization of wastewater, the parameters that are used, the impact of fairly treated or when wastewater is not treated at all, on humans and the environment. Analysis of the physico-chemical and biological processes involved in the removal mechanisms of both nitrogen and organic matter and, of course, how environmental factors and operating parameters influence the effectiveness of the treatment process and lastly, analysis of promising methods, like CANON, ANAMMOX, or SHARON, that are being investigated with the aim of implementing them in the future designs of constructed wetlands.

[gl] Existe a necesidade de atopar métodos de xestión das augas residuais, máis sinxelos que os métodos convencionais, respectuosos co medio ambiente e con baixos custes de mantenimiento e operación. Entre estes métodos alternativos atópanse os humidais construidos que, deseñados e operados de maneira óptima, dan resposta a estes obxectivos. Se ten demostrado que os humidais construidos permiten a eliminación simultánea de nitróxeno e materia orgánica, así como de sólidos e patóxenos, en augas residuais. Os resultados amosan eficacias de eliminación entre 70-94% de NH4+, 70-96% de N, 80-95% de DBO e 73-97% de DQO. Neste traballo faise unha revisión do proceso de tratamento de augas residuais empregando os métodos convencionais, dende o tratamento primario até o terciario, para posteriormente centrarse na análise dos humedais cosntruidos, tipos e funcionalidades dos seus componentes, tipos de macrófitas empregadas e as mellores condicións ambientais, así coma microorganismos presentes. Préstase especial atención á caracterización das augas residuais, os parámetros que se estudan e o impacto das augas non tratadas ou moderadamente tratadas sobre os humanos e o medio ambiente. Analízanse os procesos físico-químicos e biolóxicos implicados nos mecanismos de eliminación de nitróxeno e materia orgánica e, por suposto, a maneira na que os factores medioambientais e os parámetros operacionais inflúen na eficacia do proceso. Por último, faise referencia a varios métodos prometedores, CANON, ANAMMOX e SHARON, que están sendo investigados para a súa implementación en futuros deseños de humedais construidos.