Development of a Mathematical Modeling Approach for Implementing Effluent Discharge Analysis in the State of Goiás

Código

I-EBHE0152

Autores

Carolina Mundim de Souza Marques dos Santos, Ana Luiza Duarte de Abreu, Jorge Enoch Furquim Werneck Lima, Alberonaldo Lima Alves, Alan Mosele Tonin

Tema

WG 2.6: Water systems analysis for integrated planning & management

Resumo

Effluent discharge into water bodies poses a challenge to the maintenance of water quality and quantity in watersheds. This study presents a mathematical modeling approach developed to analyze the impacts of effluent discharges in the state of Goiás, offering an integrated approach that considers both qualitative and quantitative aspects of water pollution. The adopted modeling combines two main approaches: the Streeter and Phelps model (1925) for qualitative analysis of Biochemical Oxygen Demand (BOD) degradation in the receiving water body, and the modelling proposed by Kelman (1997) applying the alpha coefficient for quantitative analysis of the water required to dilute the effluents. This combination allows for a comprehensive assessment of the impacts of effluent discharges, considering both the quality and quantity of water in the watershed. The Streeter and Phelps model provides a visual representa?on of BOD behavior in water bodies over time and distance following effluent discharge. It allows the analysis of BOD degradation and its influence on water quality using data such as discharge coordinates, effluent flow rate, raw effluent BOD, and treatment efficiency. The dilution equations of Kelman (1997), using the alpha coefficient, estimate the flow required to dilute the effluents, considering BOD degradation along the river. The alpha coefficient shows the BOD degradation rate from the Streeter and Phelps model. It uses this value in the dilution equation, which reduces the dilution flow over time. These equations are essential for assessing the impact of effluents on downstream water availability for other uses. The practical application of the model involves obtaining input data, such as discharge coordinates, effluent flow rate, and characteristics of the receiving water body, collected by both the user and the responsible environmental agency. A case study was conducted using real data from a wastewater treatment plant in the municipality of Goiânia (Goiás). The proposed model provided detailed information on BOD degradation and the streamflow required for effluent dilution in the analyzed section. This case study proved the model's efficiency in analyzing the impact of effluent discharges on the evaluated water courses, as well as its effect on the water balance and mass balance. The approach provides important insights for water resource planning and management in Goiás, contributing to data-based decision-making for the regulation and control of effluent discharges in the state's watersheds. The proposed methodology is a valuable tool for monitoring and ensuring water availability for multiple uses in Goiás, aiding in the promotion of sustainable development and the mitigation of water pollution impacts.