Análise do uso de premissas e soluções alternativas na elaboração de projetos de sistemas de esgotamento sanitário para o estado do Ceará

Abstract

The sewage sector has been gaining attention in recent years in the Brazilian political, economic, and environmental scenario. Despite the more intense debate on the topic, there is still a need for more attention from public policies and capital investments from both the public and private spheres. On July 15, 2020, Federal Law No. 14,026 was approved, updating Law No. 11,445/2007 - also known as the New Legal Framework for Sanitation, which, among several new attributions and negotiations in relation to the first legal framework, has as one of its main objectives the universalization of the provision of sewage services by the year 2033, in which 90% of the population must have access to sewage collection and treatment. Thus, the present work aims to carry out an analysis and selection of premises and technologies for future engineering studies in the area of sewage in the State of Ceará, as a way of using better parameters to approximate the geographic, social, and economic reality of the regions, optimize investments, and comply with the achievement of the goals of the new framework. Data, information and values were collected by consulting documents, standards and previous projects on the websites of state and municipal public agencies and benchmarking studies comparing them with other concession and privatization projects. The study provided an overview of the sewage systems of the municipalities of Ceará and the Municipal Basic Sanitation Plans (PMSBs) of the State regarding the current situation and the achievement of the proposed goals. For the PMSB of the 184 municipalities, it was diagnosed that 46 still do not have the study and that 119 claimed to have it, but only 103 were found through public consultation. Of these, the established goals of 49 do not comply with the universalization goal for 2033, thus requiring revisions to adapt to the new framework. To study the variation of two parameters (infiltration rate and per capita consumption) for calculating flow rates for sizing future systems, the result was a range of 100 to 150 L/inhab.day of per capita consumption for Ceará and the possibility of using lower infiltration rate values such as 0.05 and 0.10 L/s/km for sizing infiltration flows. In addition, the possibility of using individual solutions with septic tanks with anaerobic filters and sumps for sewage treatment in districts and locations with smaller populations was proven; and the replacement of the masonry box on the sidewalk with an Inspection and Cleaning Tube (TIL).