Traditional screens can’t handle both peak and normal flows efficiently, according to Duperon. To meet regulatory compliance, the bar screens are sized for peak flow, which requires wider openings that reduce debris capture during normal conditions, leading to clogs, disruptions and costly clarifier and digester clean-outs.

Thanks to the FlexRake IQ2 from Duperon, utilities no longer have to choose between overflow prevention and screen efficiency.

Problem

Logansport, Indiana, faced challenges at its wastewater treatment plant when growth and heavier rains began regularly overwhelming an outdated pump station. The single-channel and manual bar screen posed safety risks, requiring staff to rake debris into buckets and hoist them 20 feet using a rope-and-pulley system. The lift station pumps clogged frequently because the existing static screen allowed debris to pass by and clog the pumps. Clogging resulted in significant overtime and repair costs for the town, issues that the new Duperon screen has solved.

While designing an upgrade in 2020 with controls and dual screens, the utility sought bids that also included a bypass channel to meet state requirements. When the project exceeded the budget, the owner and contractor turned to Duperon’s local representative, American Pump Repair & Service, for a solution. APRS proposed the Duperon IQ2 screen with an automatic built-in bypass.

Solution

The average flows at the pumping station was 5 mgd, and peak flows could achieve 14 mgd — nearly three times the normal flow. Traditionally, this wide range of flow rates would necessitate that a pumping station have two screens for redundancy. But a Duperon product — the FlexRake IQ2 — replaced the two components with one, solving Logansport’s problems while providing significant savings and bringing the project back within budget.  

For 95% of the time, when the flow rate is around 5 mgd the 1/2-inch bar screen delivers efficient screening of influent and protects downstream assets. The FlexRake IQ2 significantly improves solids handling by sensing conditions and adjusting speed according to debris and flow. The geometry of design allows for scraper engagement less than two inches above the channel floor to better handle settled solids while maximizing submerged screening surface area. Reengineered scrapers are stronger, remove up to four times more debris, manage large debris without jamming and reengage quickly — all without operator intervention. 

Upon power failure, the screen defaults to this bypass mode thus satisfying bypass flow requirements for this project. By eliminating the need for a separate bypass channel, the FlexRake IQ2 was a perfect fit. 

Results

Logansport was highly satisfied with the solution and that bypass requirements were met. Because the FlexRake IQ2 was able to handle the jobs of two screens plus a bypass channel, the city saved approximately $1.9 million by avoiding unnecessary construction and bypass costs. Additional benefits have included better debris capture and downstream asset protection, reduced maintenance burden, increased staff safety, and better regulatory compliance. 

Duperon, with more than 35 years’ experience inventing new technologies, has emerged as a leader in simple mechanical equipment that provides long-term value and application experience in the liquids/solids separation market.

800-383-8479 | www.duperon.com