Preventing pump blockages

Paul Boughton
Two high performance Munchpump packaged pumping systems from NOV Mono have been specified by United Utilities to improve efficiency at its Wastewater Treatment Works (WwTW) in Caldbeck, UK, by preventing pump blockages and minimising down time at the site.

The NOV Mono Munchpumps, which each consist of a Compact C Range progressing cavity (PC) pump and CB201 Muncher, were installed to replace the plant’s existing centrifugal pumps which would, over time, cause a reduction in flow or block up completely.

NOV Mono’s Compact C progressing cavity pump range has been designed to fit into compact spaces while reliably performing to the maximum duty requirement of the application. The pump uses positive displacement for process control, variable speed for accurate dosing and features a suction lift capability of over eight meters.

The CB201 Muncher model from NOV Mono has been specifically designed to meet above ground pump station requirements for delivering a conditioned wastewater through small bore pipework into a receiving wastewater treatment package.

The SB Muncher is a twin shaft, low speed high torque grinder. Each shaft is fitted with a series of interleaving cutters that allow liquid to pass through, trapping and macerating solids with their high torque cutting action. Low operating and cutter tip speeds dramatically reduce mechanical wear, and also offers greatly reduced noise levels when compared to high speed macerators.

NOV Mono Munchpump packages consist of either a SB or TR Muncher, with a NOV Mono progressing cavity pump, for sewage and sludge maceration and pumping. The twin shaft, low speed, high torque grinder has very low energy consumption - in some cases it can be as much as 5 per cent lower than a comparable submersible or centrifugal wet or dry well pump system.

Pump capacity can be limited, to offer a controlled feed, which helps improve effluent B.O.D. (Biological Oxygen Demand) loading into a small treatment plant. Being a positive displacement pump, head is independent of speed, therefore very low pump speeds can be selected to reduce abrasive wear, lowering ongoing maintenance costs. The efficient maceration of sewage also eliminates the need to screen inflow and the associated labour costs for handling and disposal of screenings.

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