Eficiência das estações de tratamento de esgoto da grande Aracaju, Sergipe

Abstract

The quality of sewage varies according to human activity and the treatment administered. Therefore, the objective of this work was to analyze the efficiency of different sanitary sewage treatment systems in the greater Aracaju region on the physicochemical and microbiological quality. Data on temperature, sedimentable solids, ph, flow, BOD, COD, oils and greases, ammoniacal nitrogen, sulfides and finally thermotolerant coliforms (TOC) were obtained from the sewage quality diagnoses prepared by the Sergipe Sanitation Company (DESO), for the Rosa Elze, Barra dos Coqueiros, Sul, Norte, Oeste and Orlando Dantas sewage treatment plants (ETE), whose spatial cutout is from January to December 2020, with this analysis of variance (ANOVA) and Scoot Knott test considering 5% significance. For the temperature parameters, all comply with the legislation, with emphasis on the ETE Rosa Elze, as well as for the pH parameter, with the ETEs Orlando Dantas and Oeste being the ones with the lowest values. There was no significant difference for settleable solids. For BOD, all stations complied with the legislation, with a significant difference for ETE Orlando Dantas, the same occurs for DQO, but there is no federal or state limit for the parameter. The limit of ammoniacal N concentration established for effluent discharge is 20mg/L, therefore, only stations in Orlando Dantas and Norte presented averages within the normative standard. For Sulfides, only ETE Norte does not comply with the 1.0mg/L limit. In relation to Oils and Grease, ETE Norte presented an average annual value above the others, with 20mg/L. In relation to TOC, ETE Oeste differed from the others, with higher TOC levels compared to other stations. As for the flow, the ETE Orlando Dantas had the lowest average, while the South had the highest, with seasonal variations. Based on the data mentioned above, the ETE Orlando Dantas fit within the quality parameters and with more satisfactory results for most parameters, adopting treatment with activated sludge associated with the chlorination process. While the North and West stations presented values above the limit for some of the variables, they adopt as treatment method the facultative ponds + maturation ponds and DAFA associated with the activated sludge and chlorination ditches, respectively.