Proposta de índice de tratamento de esgoto sanitário como ferramenta de apoio ao lançamento de efluentes

Abstract

Effluent Treatment Stations (ETEs), basic components of wastewater treatment services, basic sanitation, are essential for mitigating water scarcity, but have serious operational or design problems, which compromise treatment processes and launch effluents with lower quality than expected for the receiving water bodies. The goal of this study was the construction of a Sanitary Sewage Treatment Index (ITES), as a decision-making aid tool for the release of treated effluents, in order to to reduce the impact on water resources. For this, 50 ETEs were chosen, in the municipality of Fortaleza-Ce with four treatment technologies: UASB reactors with biofilter submerged aerated followed by chlorination (UASB + BF + CHLOR), followed by chlorination alone (UASB + CHLOR); stabilization ponds (LE) and decant digesters associated with filters anaerobes followed by chlorination (DD + FA + CHLOR). The study consisted of statistical analysis data, application of Principal Component Analysis (PCA) and construction of the index 16 ETEs with UASB and LE technologies, and the analysis of the effluent quality of 34 ETEs with all technologies analyzed. The parameters evaluated were Chemical Oxygen Demand (COD), Total Suspended Solids (TSS) and Escherichia coli (E.coli). For the index was evaluated quality in terms of compliance with launch legislation in accordance with the following service ranges: unsatisfactory (0 – 39.9), satisfactory (40 – 69.9) and excellent (70 – 100). The best ITESs generated were from stations with a UASB + BF + CLOR reactor, while 50% of the 16 ETEs presented unsatisfactory compliance with environmental legislation. For 34 analyzed ETEs, the most evaluated parameter was COD, whose concentrations mostly were above 200 mg/L. For this group of stations, 21% were positive highlights with compliance of its parameters with environmental legislation for the majority of its averages semi-annual, while 62% were non-compliant. In general, most stations evaluated are not suitable for release into receiving water bodies, requiring evaluation of your treatment processes to adapt to the requirements of legislation environmental.