According to national statistical data, only 10% of the Brazilian urban population have their sewage treated. In the rural areas, where people usually treat sewage trough septic tank systems, this value is not greater than 5%. This situation, therefore, depicts a lack of basic sanitation in Brazil, which, in turn, is responsible for the utilisation of individual systems for the treatment of sewage by more than 100 million people. Generally, soils and water rivers are, no longer, the last fate for the discharged effluents. Wetland system for the treatment of domestic sewage have been employed in different situations and arrangements (combined system) always showing outstanding performances.

The reasons which qualify this system for the treatment of effluents have been attributed to its low cost, easy maintenance and operation.

The experiment was carried out in the Agriculture Secretary's Training Center, Santa Catarina State, responsible for servicing approximately 66 people daily, and was fed with local effluent.

This work assesses the efficacy of such a kind of system, which is composed of a septic tank followed by the root zone, in the treatment of liquid effluents.