Validación del método respirométrico para determinar DBO5 en aguas residuales y naturales en el Distrito Metropolitano de Quito

Abstract

Water analysis is based on the determination of various parameters that are part of its own characteristics. This project is focused on the validation of the BOD analysis since it quantifies the organic matter in water, throughout the consumption of oxygen used in the metabolism of aerobic bacteria in a period of five days. The validation of a method consists in the study and manipulation of each one of its stages. It was done through experimentation in the fine tuning, where the specific characteristics of the method and the inoculum were determined, ensuring an adequate medium for the BOD5 analysis. The validation parameters were established by means of the statistical evaluation of the results obtained in the ANOVA, where it was obtained a percentage of recovery (% R) 100 ± 15%, a Coefficient of Variation of Repeatability (% CVr) <5 %, and a Reproducibility Variation Coefficient (% CVR) <5%. Once the validation was completed, it was found that the process complied with the previously established parameters, for which the method for the analysis of the rivers Guayllabamba, Monjas, Machángara, San Pedro and Pita was implemented to know their status with respect to the regulations applied. in the Metropolitan District of Quito, where the excess of organic load in the first three rivers was evident. Nowadays, the laboratory of the District Secretariat uses the specific procedure for the analysis of waste water and natural waters, following the parameters obtained from the validation.