Tanque de evapotranspiração como solução complementar e sustentável para o saneamento em comunidades ribeirinhas: estudo de caso na Comunidade Mojó

Abstract

This study analyzes the technical, environmental, and economic feasibility of the Evapotranspiration Tank (TEVAP) as a complementary and sustainable solution for basic sanitation in riverside communities, using the Mojó community, located in the municipality of Paço do Lumiar – MA, as a case study. Also known as the banana tree pit, TEVAP is a domestic sewage treatment system based on natural principles that combines evaporation, transpiration, and physical retention processes. It prevents the discharge of raw effluents into the soil or water bodies, thereby promoting sanitary safety and environmental protection. The methodology combined field research with the collection of primary data, application of semi-structured interviews with ten local families, socioeconomic analysis, technical design according to the guidelines of NBR 17076:2024, a detailed system budget, and a comparison with a pre-molded biodigester model. The TEVAP system proved feasible to build using widely available materials such as ceramic bricks, sand, gravel, cement, and recycled tires, employing community labor, which resulted in an estimated cost of R$ 3,198.73. The biodigester, in turn, presented a cost of R$ 4,443.32, indicating a savings of approximately 28% with the adoption of TEVAP. Furthermore, this system requires no chemical inputs and demands only simple maintenance, which favors its replication in territories with limited infrastructure. As an outcome of the research, the educational booklet “Clean Backyards, Standing Mangrove” was developed, aimed at popular environmental education, with didactic content and accessible illustrations, strengthening community understanding and local engagement. It is concluded that TEVAP stands out as a low-cost, technically robust, and environmentally effective social technology capable of promoting environmental justice and sanitary inclusion in areas historically neglected by public sanitation policies.