Application of the Ultrafiltration and Photooxidation Process for the Treatment of Rainwater

Abstract

As water resources become increasingly scarce, the concept of water reuse is gaining importance. Recently, attention has been paid to the use of rainwater as an alternative water resource. Part of this study, laboratory-scale experiments were conducted to evaluate the effectiveness and efficiency of the ultrafiltration process. The aim of the research was to assess the influence of pollutants from various roof coverings on the ultrafiltration process and the occurrence of membrane fouling. Additionally, the rainwater disinfection process was performed using UV radiation. Analysis of rainwater collected from various roofing materials, evaluating rainwater treatment by ultrafiltration in a cross-flow system, determination of the effectiveness and efficiency of the UF membrane, and additional disinfection of rainwater using UV radiation were carried out. Rainwater was collected from various roofing materials, such as steel roof tiles (RW1), bituminous shingles (RW2), and tar paper roofing (RW3). The treatment efficiency of ultrafiltration was evaluated by monitoring typical quality parameters: color, turbidity, COD, TOC, absorbance of UV254, ammonium, conductivity, and pH. Coliform bacteria, Escherichia coli and Enterococci, were monitored as total number of microorganisms at 22 ± 2 °C after 72 h. As expected, a significant reduction in individual parameters was recorded. COD of rainwater decreased in RW1 by 59%, in RW2 by 69%, and in RW3 by 74%. The ultrafiltration process ensured the complete retention of the coliform bacteria and E. coli. Complete elimination of microorganisms was demonstrated when the ultrafiltration process and UV radiation disinfection were combined.