Sistema de suporte à decisão para análise de outorgas de lançamentos de efluentes de fontes pontuais em rios

Abstract

The decision-making process related with wastewater discharges into rivers requires the analysis of several aspects: outflow structure location, water availability and receiving water body qualitative conditions. Estimates of water bodies dissolved oxygen and the biochemical oxygen demand levels as well as estimates of phosphorus and nitrogen compound concentrations after the beginning of the outflow operation are important variables to be considered. The present study aims at the development of technological instruments for supporting the decision making processes about wastewater discharges location and permit, taking into account hydraulic/hydrological characteristics, water body quality recovery capacity and water body quality restrictions. The developed Decision Support System (DSS) includes QUAL2E water quality model, database and communication interface between user and computer to allow simulation of wastewater discharges in different water course locations. Simulation results are compared with water quality parameters restrictions established for the receiving water body, indicating in what positions the new wastewater outflow structure could be located, without violating water quality parameters limits. The results are presented in such a way that the previous and simulated parameters, considering the new discharges, may be easily compared. The DSS presents a module related to the control of the existing and new wastewater outlet, allowing fast analysis of different scenarios of pollutant discharge location restriction. The system demonstrated to be a useful decisionmaking process tool for wastewater outlet location and permit analysis, considering potential impacts on receiving water bodies. The DSS can be utilized for demonstration of possible effects of different decisions related with water resource management, such as influence of previous water supply intakes and wastewater discharge permits over new outlet permits and needed increase in effluent discharge treatment efficiencies for respecting more restrictive water body quality conditions.