Many wastewater treatment plants are facing a dilemma. They’re trying to handle increased flows without increasing the size of their channels and, at the same time, achieve higher debris capture to support new downstream processes.  

A retrofit solution that increases the wetted area of the screen but still fits an existing footprint does exist. An installation in Wisconsin recently increased capacity from 8.2 mgd to 11.1 mgd per screen within the same hydraulic gradient by installing an FSM perforated plate Filterscreen multi-angle design.

All about angles

To achieve greater throughput with minimal channel length available, FSM utilizes a 30-degree angle for the submerged portion of the screen and then transitions to a 75-degree extraction angle to transport the screenings from the channel. This combination doubles the wetted screen area, reduces velocity through the screen for better capture and provides an operating floor footprint that does not change the solids discharge point.

The multi-angle design uses the same features of the FSM single-angle perforated plate screen, which is independently verified to achieve 85 percent debris capture.  

As with the single angle Filterscreens, a continuous screen belt of perforated plate panels traps debris on the surface of the panels and moves it to discharge where a brush cleans the debris from the panels.  

The proprietary, self-adjusting brush acts as the primary cleaning mechanism, which keeps water usage to a minimum. The self-adjusting brush requires no manual adjustment.

Enviro-Care Company, a member of the WAMGROUP, supplies screening and solids/grit management equipment to the North American water and wastewater markets. Brands include SAVI, SPECO, WAM and FSM Frankenberger. Contact Enviro-Care for a copy of the white paper titled Balancing Channel and Screen Velocities.  |


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