Membrane technology begins to be widely employed in wastewater treatments with several advantages, such as compact system, and excellent treatability of water quality parameters. However, there are still drawbacks in membrane technology, such as high construction cost, high operating cost, and frequent backwash by membrane fouling.
In order to reduce membrane fouling, ozone was applied in MBR (Membrane Bioreactor) system using synthetic wastewater. 0.7mg/l of ozone concentration at which microbial activity and effluent flux was highest was chosen for an optimum dose. It was found that ozone application reduced membrane fouling remarkably. A backwash period was about 2 weeks before ozone application, while it was extended to about 7 months after ozone was applied in MBR process. Not only backwash period was extended for a long period of time, but also removal rates of water quality parameters were enhanced by ozone application in wastewater treatment. Even though ozone was applied for more than 7months, there was no sign of membrane damage.
It was revealed that appropriate ozone application may prevent membrane fouling from microbial activity, so that buildup of head loss may be suppressed, and backwash period may also be extended for a long period of time.