Avaliação de sistemas de tratamento de esgoto e aproveitamento de água de chuva em unidades educacionais

Abstract

In various regions of the world, water reuse activity grows as an alternative front to the scarcity and inaccessibility of water resources, although it is practiced as a water quality management tool in both dry and damp places. In northeastern Brazil it hasn’t been different: as the most vulnerable region in the national territory, rainwater and sewage utilization are becoming necessary activities for conservation of this resource. In buildings located in places with no sewage system, we have used low-cost sewage treatment systems, located in their respective area. Although simple, these systems may confer to the effluent compatible qualities for its disposal on the ground or even for irrigation. This has been a present reality in various campuses of IFRN where sewage is treated locally in single units, and the effluents and the collected rainwater have been infiltrated into the soil and/or used for irrigation of green areas (gardens and soccer fields). Such practices have contributed to the reduction of water consumption on the campuses. However, questions and concerns still exist regarding the risk of contamination of these areas and disease transmission for the inhabitants of the campuses. Faced with this problem, the objective of this study was to evaluate sewage treatment systems and rainwater use on IFRN campuses in order to contribute to reconcile the rational use of available water and thus serve as a model for other similar educational units. For this we checked, in IFRN units, the sewage treatment technologies and rainwater capture and storage systems, considering size, location, population, final effluent destination (in sewage treatment plants), the use of rainwater, and water quality. The systems were evaluated monthly, from March to September 2014. As a final result, it is emphasized that the characterization of the educational units’ sewage behaved differently from domestic sewage; and treatment plants featured lower efficiencies than expected. Regarding the utilization of rainwater, we found that the collected water has compatible quality for irrigation of green areas. This work also allowed, based on the evaluation of the various systems, to present general propositions for technological development and monitoring of sewage treatment systems and rainwater utilization to the campuses and similar units.