A H2O Engenharia Ltda.  was contracted by Thyssen Krupp CSA (TKCSA) to prepare Mass Balance (flows and solid loads) of the existing liquid streams at the plant located in the municipality of Santa Cruz, in the State of Rio de Janeiro. In addition, Performance Evaluations of Industrial Disposal Treatment Plants (ETDIs) were carried out in the same industrial complex. TKCSA has an extensive database on the flows of liquid streams in the plant, which contributed to the reliability of the statistical analysis performed. However, dealing with the extension of the database proved to be a separate challenge, since it was necessary to use more detailed statistical methods in the compilation and evaluation of the data available. For this task, H2O Engineering developed iterative flowcharts that allowed to evaluate the flow data and solid load of the large production units (blast furnace, coke oven, steelworks, etc.) in an individualized way, bringing valuable information to each stage’s operation teams of the productive process. All the flowcharts were elaborated based on the P & I diagrams provided by TKCSA, which facilitated even more the correlation of the calculated theoretical data with the practical experience of the teams that operate the units. The performance evaluation of the ETDIs focused on verifying the behavior of the ETDIs regarding the removal of the parameters specified in the NT-202.R-10. In this way, it was possible to verify the necessary adjustments to the treatment processes and to elaborate a preliminary schedule for their implementation.