For the fine filtration of water at:

• Waste water treatment plants
• Sewage treatment plants
• Water reclamation facilities
• Combined storm water overflows
• Potable water treatment plants
• Various screening applications

STS Band Screen
STS Band Screens are designed for fine screening of wastewater at the inlet to Waste Water Treatment Plants where a continuous means of removing solids is required to protect downstream equipment and improve plant efficiency. Fitted with 9 mm thick mesh ProPaPanel® with tapered holes, eliminates hairpinning and blinding experienced with alternative panels such as metal perforated plates, woven wire and wedge wire screens. The STS Band Screen utilizes a Flow Thru Pattern which has proven to be a reliable and effective fine screen both as a retro fit for existing sites as well as on new installations of the headworks of conventional raw sewage inlets (WWTP’s and WRF’s) and combined storm water (CSO’s) plants.

ADVANTAGES

Superior Screening Capture Ratio Low operating Head Loss No Hairpinning / No Brushes

The Problem
A variety of different screen flow patterns and screening media have been applied to the headworks of sewage treatment plants over the past century. Each type of screen came with numerous inherent flaws that either prevented efficient screening or required constant maintenance. Pursuant to discharge demands requiring a round hole, ordinary perforated plate has been applied to the oldest mechanical screen design, the thru flow band screen. The thin perforated plate (usually 1/16" or 2mm thick) allows fibrous debris such as body hair, cotton and rags to staple or hair pin around the plate eventually blinding the screen. Removal requires constant attention, high pressure spray and/or rotating brushes.

The Solution
Brackett Green’s engineers spent several years working with various combinations of plate thickness and hole diameters to develop a screening media that would resist hairpinning. The end result is known today as the ProPaPanel® (US Patent No. 5407563). This thick plate (9mm/3/8") screening media resists hairpinning, contains a tapered hole to prevent plugging and is made of a corrosion resistant, high strength material. The combination of unique benefits of the ProPaPanel and efficient seals between carrier baskets and roll around track establish the STS Band Screen as a highly economical solution. ProPaPanels are available with 6mm (1/4") diameter to 2mm (1/16") diameter holes. The ProPaPanel also requires a low backwash pressure (30 PSI) to positively clean the screen. This same wash water is typically used up to three times: once to backwash the screen, again to transport the screenings via gravity conveyance and a third time in the screenings conditioning process. Today Brackett Green has installed the STS Band Screens at sewage treatment, water reclamation facilities and combined stormwater overflow plants in numerous countries.

The Process
The STS Band Screen is installed across the full channel width. Smaller debris is retained by the rising side of the interconnected ProPaPanels (1). Larger debris is elevated by lifting lips (2) to the screening trough where pressurized spray nozzles (typically 30 PSI) located inside the screen head section (3) cleanse the traveling mesh panels before re-entry into the channel flow. Asluicing trough collects and transports the wash water and screenings by gravity flow to a solids conditioning and dewatering system eliminating the need for conveyors.

The STS Band Screen uses the thick plate patented ProPaPanel with 6 to 2 mm diameter tapered holes which avoids the problem of hairpinning or blinding by fibrous debris, fats and grease. ProPaPanels only require low pressure water to remove debris, eliminating the need for rotating brushes. It also aids in sluicing the solids to the conditioning and dewatering system. Other features include: shaft mounted drive (4) and antifriction bearings (5) to reduce maintenance. A totally enclosed head section (6) with access panel for odor control and component accessibility from deck level. Roll-Around Foot Terminals (7) to eliminate foot sprockets and reduce maintenance. Positive sealing (8) so that nothing larger than the mesh opening bypasses the screen panels.

The following table should be considered as general guidelines.