Garantia da qualidade de efluentes de tanques sépticos/filtros anaeróbios e de reatores Uasb – avaliação com número fuzzy triangular e índice de conformidade

Abstract

Sewage treatment systems are often neglected as to the quality of the treated effluent. Many fail to perform the proper treatment for lack of monitoring of their performances. The control of effluent treatment plants is extremely important to ensure the quality of the receiving bodies, being directly linked to the maintenance of human health, assisting in environmental management processes. For this, it is necessary to meet limits determined by specific standards for each quality parameter of the treated effluents. The reliability of a system is obtained through monitoring capable of showing the probability that it will not fail in its operation in a certain period of time. In this work, two methodologies are used: fuzzy agreement index (an application of the concepts of fuzzy logic through the Fuzzy Triangular Numbers method) and Index of conformity, both focusing on the non-conformity of a parameter or set of parameters. Twelve systems were part of the study, six of which were septic tank/anaerobic filter and six UASB reactors, in which three quality parameters were analyzed: COD, E. coli and SST. The results obtained by the two methodologies were similar, showing that most of the systems were outside the normative limits for the SST parameter and that the E. coli parameter had the best guarantee values in relation to the others. Easy-to-use monitoring methodologies such as these are useful to assist in the decision-making process, designating actions for improvements in TSEs that are actually needed.