Complete extraction package for Dunstable sewage

A major project to refurbish a sewage treatment plant in Bedfordshire has seen the original step screen units removed and replaced with two Mono L Series Discreens, plus screw extractor systems

A major project to refurbish a sewage treatment plant in Bedfordshire has seen the original step screen units removed and replaced with two Mono L Series Discreens.

Underlining its ability to supply either individual products or complete packaged systems for this type of application, Mono also provided two screw extractor systems and a single screw conveyor to partner an existing unit.

The original step screen units installed on the Dunstable plant 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 conveyer systems.

Throughout this large-scale project, there was a need to maintain the flow through the plant, and Mono 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.

The Mono range of L Series 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 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 the 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.

A fully automated control system can also be supplied which warns of any system failure, and helps ensure continuous operation.

The screw extractor has swivel support and an easily replaceable part of the spiral along the screen to simplify service and reduce maintenance costs.

When used in conjunction with a Mono Muncher, you have enhanced extractor performance, and as the screw extractor washes and dewaters screenings, you minimise the extent of secondary equipment Mono can undertake all aspects of a project such as this, from the supply and installation of a single unit through to full turnkey installations which include all design work, M and E installation, commissioning and ongoing service.

The company can also supply all associated items such as control panels, walkways, instrumentation kiosks, fencing, pipework and valves, operating under Main Contractor status.

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