Two Mono Stormscreen units have been selected for installation in a CSO overflow chamber in the centre of a Lake District beauty spot at Bowness, close to Lake Windermere.
United Utilities chose the two SC1A15064 Mono Stormscreens to quickly improve an existing storm water overflow system by installing an extra level of screening. Offering advantages such as self-powered operation and easy installation, the units are designed to screen the storm water flow before it passes on to a pumping station.
The existing screens at the station had caused system blockages posing a threat of subsequent flooding. United Utilities was impressed by the flow-powered operation and self-cleaning action offered by the Mono Stormscreens.
According to United Utilities, the Bowness CSO overflow chamber is located under a main road and accessed via a single manhole. The equipment was installed through the manhole by Mono personnel who have experience in working in confined areas.
The automatic start and flow-powered operation were important factors as there was no power available in the chamber. Since installation the Stormscreens have run continuously for up to ten days at a time during storm conditions without suffering any blockages.
The two Stormscreen units have a combined maximum capacity of 1620m³/h. In addition to the screens, Mono supplied and installed stainless steel weir wall mounting frames, Stormscreen cradles, a guide rail system, plus lifting chains and a chain management system.
All the Mono equipment installed at Bowness is designated as suitable for use in a Zone 1 hazardous area. Elongated access ports to the chamber were provided to allow a guide rail system to be installed to enable easy periodic inspection.
How Mono Stormscreens operate
A standard 400mm diameter mesh drum incorporates a paddle wheel fitted with adjustable brushes. As water flows through the channel and into the unit, the mesh drum captures any solids above 6mm in size. The screened flow passing through the unit powers a turbine mounted below the mesh drum, which in turn drives the paddle wheel. As this rotates, the brushes clean the mesh drum and return any solids back into the main flow.
An integrated scumboard protrudes into the main flow and deflects large floating solids away from the screen, increasing its self-cleaning capability. The Stormscreen unit can also be supplied with an electrical motor if existing power is readily available.
Key benefits of Mono Stormscreens:
- Conforms to discharge consent and AMP 3 guidelines in line with the Environment Agency’s strict requirements
- Provides an economic solution for storm overflow inlet channels
- Combines low maintenance with highly effective screening
- Requires no electrical installation work
- Self-cleaning operation
- Minimal running costs