Modelagem da influência da infiltração de águas pluviais em um trecho do interceptor leste de esgoto da zona costeira de Fortaleza, Ceará

Abstract

The infiltration of rainwater into the sewage system is a problem that can have several consequences. In periods of heavy rain, the capacity of the sewage network can be exceeded, causing flooding and flooding in the streets. In addition, contamination of water bodies by waste present in sewage can compromise aquatic life and generate environmental problems. One of the ways to contribute with means to propose or test actions that can avoid or reduce this problem involves the use of computational modeling. In this context, the present work aimed to identify, through hydraulic modeling, the critical points liable to rupture and overflow of a section of the Eastern Interceptor (IL) of the sewage network in Fortaleza, Ceará. Computer simulations were performed using the PCSWMM software. To estimate the RDII (volume of rainwater that infiltrates the sewage network) the methodology of RTK parameters was applied. The impact of the contribution of rainwater from the sub­basins of Riacho Maceió and two other sub­basins (S95 and S102) of Vertente Marítima, one located at the entrance and the other at the end of the discharge line of Praia do Futuro II Sewage Pumping Station was evaluated. Simulations were carried out for dry weather and with rainy events with maximum precipitation, using an IDF curve (intensity­duration­frequency), considering different return periods (2, 5 and 10 years) and values of the R parameters of 1%, 3%, 5%, 7% and 10%. After carrying out the simulations of the different scenarios, no overflow was found in the culverts of the analyzed IL stretch. However, critical points were identified, some sections of the sewer pipe are functioning as penstocks. Although there was no overflow in the culverts in the section analyzed, it is important to take into account the critical points, as they can lead to operational problems or structural failures.