Singular Spectrum Analysis of Pathogenic Microorganisms in a Sanitary Wastewater Treatment System

The variation in the population of pathogenic microorganisms in wastewater over time can be predicted by single-spectral analysis, which outperforms conventional multivariate methods. This type of information is important for the performance of sewage treatment plants. The objective of this study was to monitor the variability of the population of microorganisms and the removal of microbiological attributes of sanitary wastewater in a treatment plant equipped with a septic tank and solar reactor. Effluent samples were collected monthly upstream of the septic tank and inside the solar reactor, and the effluent was exposed to solar radiation. Total coliforms and Escherichia coli were analyzed by means of descriptive analysis and singular spectrum analysis. Solar disinfection obtained bacterial inactivation levels of 99.94%, equivalent to 4 log units for the Escherichia coli population, and 99.45%, equivalent to 3 log units for the total coliform population. For the inlet effluent, the prediction showed a trend of growth alternating with periods of stability. For the outlet effluent, the prediction was able to provide regular data up to the first six months, showing error and overestimation of the data for the final six months of the study.