“We completed the Yellow River WRF Improvements Project in 2012. This project replaced an aging 14.0 MGD conventional activated sludge facility with an advanced 22.0 MGD MBR facility. The MBR facility includes third party submerged fiber membrane for solids separation. The membrane manufacturer required, at a minimum, 2mm screening to protect the .04 micron membrane. We decided to purchase and install OVIVO® drum screens and they have performed outstandingly. We employ two-stage screening – stage one occurs at our headworks, which is protected by JWC grinders and in stage two, the resulting influent is pumped up to our preliminary building and into our 5mm drum screen. We have one duty and one standby mechanism, each rated for 64 MGD. The 5 mm drums were placed into service in December 2009. During that time, we have replaced drum seals twice and one drive unit gearbox.
After preliminary screening, grit removal, and primary clarification, we protect our biological basins and membrane tanks with two 2 mm drums – one duty and one standby, each rated at 32 MGD and commissioned in April 2010. Other than routine preventative maintenance, we have not performed any corrective maintenance on the 2 mm screen. Our average daily flow is 14.0 MGD and we remove approximately 12 to 15 tons of screenings a week. We drain and clean our primary clarifier quarterly, annually clean the bio-basin and inspect our MBR cassettes monthly. We have no evidence of screenings, rags or hair getting past our screening processes. Our MBR Facility is operating as well as (better than) any in the world and I attribute that a lot to the effectiveness of our Ovivo drum screens that protect our biological process and membrane solids separation.”