Dimensionamento de um sistema de captação de tempo seco em área costeira e avaliação da sua eficiência para redução de lançamento de esgotos domésticos no corpo hídrico receptor com auxílio de modelagem matemática Quasi-2D em multicamadas - MODCEL. Estudo de caso em Maricá, RJ

Abstract

Disorganized urbanization and the absence of adequate sewage systems have caused serious environmental and sanitary impacts, especially in coastal municipalities such as Maricá (RJ). Given this scenario, the present study aims to design and evaluate the efficiency of a Dry Weather Flow System (DWS) in reducing the discharge of domestic sewage into receiving water bodies and in maintaining the hydraulic efficiency of the stormwater drainage network, in order to prevent flooding resulting from the implementation of these structures. The methodology adopted was based on the integration of geoprocessing tools and quasi-2D multilayer hydrodynamic modeling, using the MODCEL model, developed at the Computational Hydraulics Laboratory of COPPE/UFRJ. Initially, the socio-environmental characterization of the Mumbuca River basin, the analysis of the projected drainage, and the estimation of organic loads discharged in dry weather were carried out. Subsequently, the CTS system was proposed and dimensioned, considering technical criteria for sewage disposal and its integration with the stormwater drainage system. Hydrodynamic simulations, performed for dry weather conditions and for a precipitation event with a 10-year return period, allowed for the simultaneous evaluation of the reduction in pollutant load and the hydraulic behavior of the system. The results indicated that CTS proved highly efficient in intercepting irregular sewage discharges in the studied area, reducing approximately 90% of the annual Biochemical Oxygen Demand (BOD) load discharged into the receiving water body, without compromising the performance of the stormwater drainage system. It is concluded that the implementation of Dry Weather Flow Interception represents a technically viable and environmentally efficient alternative, acting as a complementary measure to conventional sewage systems and contributing both to the improvement of environmental quality and to the mitigation of flood risks in vulnerable urban areas