ABSTRACTION IN DRY WEATHER AS AN ALTERNATIVE TO IMPROVE UNITARY SANITARY SEWAGE SYSTEMS IN BRAZIL

Abstract

The study aims to analyze the feasibility of implementing a dry weather collection system as a technical solution to the challenges related to sewage collection and treatment in unitary systems in Brazil. The proposal seeks to minimize the impacts on Effluent Treatment Plants and protect water bodies, contributing to the fulfillment of the goals of the legal framework for basic sanitation and the Sustainable Development Goals. The methodology adopted involved a literature review, document analysis and a case study. The data were collected from scientific databases, such as Scielo and Scopus, and from official sources. The information was critically analyzed regarding the technical feasibility of capturing in dry weather, and sizing calculations were performed in Excel spreadsheets to simulate the operation of the system in different scenarios. The proposed model considered parameters such as sewage flow, rainfall intensity and operational capacity of the Effluent Treatment Plants. The results of the study included the development of a conceptual design for the dry weather catchment system, with detailed calculations of pure and combined sewage flow. Specific interception points and sizing were defined, such as collection boxes, pumps and operational configurations based on a set point of 190 mg/L of Chemical Oxygen Demand - COD. The system had the potential to reduce the overload in the Effluent Treatment Plants, ensuring a maximum flow of 5452 m³/day and compliance with the parameters of the Resolution of the National Council for the Environment - CONAMA and environmental standards. The study points out that the dry weather collection system is a viable technical solution to improve the efficiency of biological treatment and reduce environmental impacts from the discharge of untreated sewage. However, it is recommended that future research be carried out to prepare a detailed executive project and evaluate the technical, economic and socio-environmental feasibility of the proposed model.