Proposta de um sistema de tratamento de efluentes para a localidade de Missí no município de Irauçuba/CE com o uso de reatores UASB seguidos por lagoa de polimento

Abstract

Basic sanitation encompasses a set of actions aimed at maintaining public health and environmental preservation, including water supply, sanitary sewage, urban drainage, and solid waste management. Its quality directly reflects public policies and the socioeconomic and cultural aspects of a region, maintaining an interface with health, the environment, and urban development (SOUZA, 2009). The discharge of effluents into water bodies can cause severe environmental impacts, such as eutrophication and contamination by pathogens, compromising water quality and restricting its use. Under natural conditions, a water body maintains ecological balance, but the introduction of pollutants disrupts this stability, leading to environmental damage. To minimize these impacts, proper effluent treatment is essential. Sewage treatment processes can be physical, biological, or chemical, with UASB reactors being a well-established and compact technology. However, they require daily operation and post-treatment for pathogen and contaminant removal. In Irauçuba, water supply coverage is 74.18%, while sewage coverage reaches only 31.78%. Given this scenario, compact and efficient systems, such as UASB reactors followed by polishing ponds, represent a viable alternative for the region. This study proposes the design of a sewage treatment system for the district of Missí, located in the municipality of Irauçuba/CE, adopting UASB reactor technology followed by a polishing pond as post-treatment. The system includes a preliminary stage with a 3-inch Parshall flume, a grate with 20 mm spacing and a section of 9.5 x 38.1 mm, as well as a sand trap measuring 0.30 m in width, 2.20 m in length, and 0.40 m in height. The secondary treatment will be carried out by three UASB reactors, each with a 4.5 m diameter and 5.0 m height, operating with a hydraulic retention time (HRT) of 7.74 hours. The treated effluent will then pass through a polishing pond measuring 60.0 m in width, 100.0 m in length, and 0.80 m in depth. With this system, an efficiency of 97.89% in BOD removal and 99.9984% in coliform removal is expected, ensuring that the effluent meets current environmental standards.