Uma contribuição para a gestão sustentável do tratamento de esgoto sanitário urbano de Juazeiro do Norte – CE.

Abstract

It is well-known that the basic sanitation scenario in Brazil is progressing slowly, especially with regard to sewage treatment, with total coverage reaching only 56% of the Brazilian population. Moreover, the lack of sustainability in the management of wastewater treatment plants stands out, as they are limited to merely complying with legislation. In view of this, this study aims to evaluate the sustainability of the wastewater treatment system in the city of Juazeiro do Norte - Ceará, evaluating the current performance of Wastewater Treatment Plants (WWTPs) and their potential environmental impacts, as well as suggesting improvements in operation and maintenance. The study was conducted at the WWPs that make up the treatment system of the city of Juazeiro do Norte: Malvas WWTP, Três Marias WWTP, and Tenente Coelho WWTP. The first stage of the work involved acquiring the necessary data for the research from Cagece, as well as conducting technical visits to the plants. After receiving the information, the treatment system was characterized, followed by the impact assessment using the Life Cycle Assessment (LCA) tool. Additionally, based on the assessments conducted throughout the study, operational improvements and adjustments to the maintenance protocols were suggested. The Malvas WWTP showed low efficiency in organic matter removal, with only 56.17% of COD removal, E. coli at 6.98E+03 MPN/100 mL, a pH of 8.05, a temperature of 28.42°C and absence floating materials in the treated effluent. At the Três Marias STP, COD removal was also low, with an average of 45.75%. The treated effluent presented 3.47E+02 MPN/100 mL of E. coli, a pH of 7.41, and a temperature of 29.85°C. The Tenente Coelho WWTP was the plant that stood out the most among the three WWTPs studied, in terms of operational performance. The average organic matter removal was 79.97%, and 1.66E+01 NMP/100 mL of E.coli, a pH of 7.57 and a temperature of 29.23 ºC in the final effluent. The LCA identified the main midpoint impacts, highlighting the impact of Climate Change and Photochemical Oxidant Formation that occurred in all three seasons. The impact of human toxicity had significant values at both the Três Marias and Tenente Coelho WWTPs, due to the use of chlorine in the disinfection stage. In the endpoint approach, midpoint impact categories were associated with Ecosystem Damage and Human Health. Among these improvement proposals, the following stand out: conducting BOD-analyses, nutrient assessments, and other indicators by the Regional Laboratory; establishing an Environmental Management System; and recovering and reusing resources generated by the WWTPs, such as sludge, treated water, and biogas. The Malvas WWTP proved to be more relevant in the impacts generated in the protected areas, and Human Health is the protected area that suffers most from the impacts generated by these WWTPs, mainly due to climate change, the formation of photochemical oxidants and the toxicity of chemical products in human beings.