Disinfection of rainwater as a way to their microbiological stability and safe use

Department of Water Protection and Purification, Rzeszow University of Technology, al. Powstańców Warszawy 12, 35-095 Rzeszów, Poland

^* Corresponding author: mzdeb@prz.edu.pl

Abstract

Research on the microbiological quality of rainwater collected from roof surfaces indicates their significant contamination with microorganisms, including potentially pathogenic ones. The aim of the research was to attempt disinfection of rainwater with chemical methods and to evaluate the effectiveness of this disinfection. The research was carried out with the use of appropriate means in the case of decontamination of large volumes of water, when it is important to maintain their biological stability - chlorination and ozonation. After the disinfector was administered for 4 weeks, bacterial microflora (stability) was observed in stored water. The control was carried out by determining the total amount of bacteria at 37^°C and the total amount of bacteria at 22^°C on the reference medium (agar A) and on the non-standard substrate (R2A agar). The number of indicator bacteria was also determined: fecal streptococci and Escherichia coli (on the chromogenic medium). Changes in the amount of microorganisms after disinfection processes were also monitored by flow cytometry. The research results clearly indicate better chlorinating disinfection effects. It allows the removal of indicator microorganisms in a relatively short time (1 hour), and the effect of the disinfectant lasts up to about a half month.