Investigating the Performance of Membrane Technology with UV System for the Treatment of Gray water and Rainwater

Graywater and rainwater reuse is one of the primary alternatives for diminishing water consumption in households, commercial and industrial buildings. However, investigating the performance of membrane technology coupled with UV system for the treatment of gray water and rainwater needs more applicable information. The purpose of this study is to evaluate the performance of an experimental system based on membrane technology combined with UV for the treatment of gray water and rainwater in Iran. In this regard, at different pressures (9.5, 4.5, and 1.5 bar), different arrangements of membranes, including microfiltration (MF), ultrafiltration (UF), and reverse osmosis membranes were investigated along with UV lamps. Laboratory scale experiments were conducted to investigate the potential of these technologies and present an optimal membrane arrangement. The efficiency of the process has been discussed in terms of turbidity, TDS, pH, COD, Escherichia coli, and total coliforms. The results indicated that for both gray water and rainwater treatment, the arrangement consisting of a screen, MF, UF, RO, and UV with a pressure of 9.5 bar is the best scenario for reducing COD, TDS, turbidity, and coliform. According to the obtained results, the output flow in the optimal state was 6 liters per minute, and the mentioned scenario was able to remove 95% COD, 98% TDS, 96% turbidity, and 100% coliform from graywater, as well as 82% COD, 94% TDS, 91% turbidity, and 100% coliform from rainwater. Therefore, the study acknowledges that membrane technology with UV is an attractive process and will play an important role in future sustainable life.