Modelagem matemática na gestão ambiental fluvial: simulação dos impactos no sistema receptor de efluentes, para orientar operação de tratamento de esgoto, sujeito a variações meteorológicas transitórias

Abstract

This paper demonstrates a mathematical modeling technique for fluvial water quality subject to transitory impacts from poured sewage after gales, developed to “unitary systems” (sewage along with rain drainage, in old and cold countries – North Hemisphere), which is useful to guide, in real time, decisions for the treatment operation of this sewage. By integrating an international research line, this technique may also serve, along with optimization tools, to real-time planning and management of fluvial systems with transitory disturbances by several reasons.Originally, it would not be applied to Brazil: at the end of the 19th Century, it was established in the country a well-intended preference for collecting sewage in a public network apart from the drainage – the latter is subject to tropical downpour. However, despite such philosophy being still predominant in projects, the aging of the two systems and irregularities continuously introduced in land and public facilities has been promoting an increasing promiscuity between both of them (examples: illegal connections, underground leaking) and elevated flow rates led after gales towards treament stations to the extent of having their capacities overflown. This way, the proposed simulation technique is useful to the Brazilian context. Its employment is demonstrated in a real case, by a ranking of the treatment operation alternatives based on the resulting fluvial quality simulations – therefore, aiming at an environmental objective. Keywords: Mathematical simulation of the fluvial water quality; Impacts of the sewage on rivers; Hydric system environmental management.