The original step screen units installed on the Dunstable plant’s inlet flow had proved to be inefficient and unreliable. The replacement Discreen units now screen the inflow, allowing solids to be collected on the screen surface of the screw extractors. An ultrasonic level sensor operates the rotating screen spiral to run for the time necessary to clean the screen and convey the solids towards the discharge chute, ready for dewatering and removal by the conveyor systems.
Throughout this large scale project, there was a need to maintain the flow through the plant, and Mono’s installation personnel operated an extended shift pattern in order to minimise disruption, whilst also working closely with the customer to ensure that all regulations were adhered to.
Mono’s range of Discreen units offer an effective screening solution for pumping stations or inlet works. The units can be used alone on water abstraction intakes and storm overflows, or combined with a Mono Muncher to screen and grind solids within a flow, and packaged with a screw extractor for screenings removal.
Equipment and installation flexibility allows many different channel widths and depths to be covered, with minimum
or no civil works required when fitting into existing channels. The Discreen’s self-cleaning action reduces operating costs and a high capture rate efficiency eliminates the problem of ragging and material build-up. Featuring a series of shafts fitted with intermeshing rotating discs, the Discreen gently conveys solids across the face of the screen to the point of discharge, while the main water flow passes through the disc stacks.
The Discreen typically features between three and fourteen shafts per unit, with depths between 200-1750mm. The aperture size is controlled by varying thickness of the disc spacers to either 2.5, 5.0, 9.0 or 18.0 mm to meet
both onsite and European legislative requirements.