DOMESTIC EFFLUENT TREATMENT THROUGH INTEGRATED SYSTEM OF SEPTIC TANK AND ROOT ZONE Luiz S. Philippi, Rejane H. R. da Costa and Pablo H. Sezerino Departamento de Engenharia Sanitária e Ambiental, Universidade Federal de Santa Catarina, Caixa Postal 476, 88040-900 Florianópolis-SC, Brasil ABSTRACT 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 tank septic system, this value is not great than 5%. This situation, therefore, depicts a lacking of basic sanitation in Brazil, which, in turns, is responsible for the utilisation of individual system 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 these 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 from the Santa Catarina State, responsible for attending 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. KEYWORDS Constructed wetland; pollution control; root zone; rural sanitation; septic tank; wastewater treatment; wetland System; INTRODUCTION The situation of the Brazilian basic sanitation depicts a picture of the social and economic conditions of its population. According to data from the Human Development report (IPEA, 1996) only 10 % of the Brazilian urban population have their sewage treated. This situation reveals, on the other side, that more than 100 million people treat their sewage through the utilisation of septic tanks as individual treatment systems, being soils and water rivers as the last fate for the discharged effluents (Philippi, 1997). Another studies have demonstrated similar situation in the rural areas where only 2 % of the total residences have available sewage treatment services while another 5 % disposes their sewage in septic tanks (Lobo e Santos, 1993).These data point up the lacking of basic sanitation in Brazil, which, in turns, justify the application of new technologies in this field. Therefore, this works presents a well known and world-wide utilised system (primary treatment- septic tank) associated with a secondary treatment (root zone) that is totally supported by the soil-plant relationship. From the environmental point of view, a sanitation design should be able to respond for