Reliability analysis as a support tool for projects focusing on nonpotable uses of treated wastewater in steel industries

Abstract

In a scenario of increasingly frequent water crises, the use of treated wastewater is an important water management tool, with quality standards being developed worldwide to ensure safety in such practices. In this context, it is necessary to guarantee the reliability of wastewater treatment plants (WWTP). Reliability has been used to predict the probability of reaching the established standards or determine the design concentrations required to achieve them. This study associated the reliability concept with the study of WWTP in the steel industry, focusing on water use. The method developed by Niku et al. (1979) and used by Oliveira and Von Sperling (2008) was used to determine the coefficient of reliability, the mean project concentrations, and the percentage of compliance with the parameters required by the legislation of 3 WWTPs that treat industrial effluents and 1 WWTP that treats sanitary effluent. The percentages of compliance with legislation for most parameters were equal to or close to 100%, indicating an excellent performance of the 4 WWTPs, which could even allow the adoption of even higher levels of reliability. Therefore, the reliability studies together with a modeling of the contaminants’ dispersion in the soil proved to be a very interesting approach for projects related to non-potable uses of treated wastewater in steel industries.