NOV Mono Completes Project to Ensure Quality Levels for Welsh Water

The project centers on an EZstrip progressing cavity pump which is now being used on sewage transfer duties to ensure that the plant can guarantee the quality of the treated sewage under any flow conditions.

Powered by a 4kW motor and operating at a duty speed of 226 rpm, the EZstrip pump draws sewage from the centre of the final settlement tank at Dwr Cymru’s Crymych treatment plant. It pumps the sewage back up to the head of the treatment system, from where it returns back through the filter bed to the final tank. This ensures that the plant’s biological filters do not dry out and remain effective, even in very low flow conditions. This in turn helps to maintain the quality of the final sewage within the required boundaries, at all times.

Mono was approached because of its ability to provide a full turnkey package which covered all the stages, from initial site survey, design and manufacture, through to full mechanical and electrical installation. Working closely with the project’s civils contractor, Mono installed the pump, suction pipe, rising main, control panel, overpressure and high temperature devices and completed the final testing and commissioning. Both the electrical and mechanical work were handled by Mono, who have since completed a very similar project at Dwr Cymru’s Lamphey treatment plant.

The progressing cavity pump at the centre of the Crymych project features Mono’s revolutionary EZstrip design which allows it to be maintained-in-place. This provides a quick and easy way to disassemble, de-rag and maintain the pump without the need to disconnect suction and discharge pipework. This reduces a typical day-long maintenance operation down to just 30 minutes. Available in cast iron or stainless steel, and with a choice of rotor and stator materials, the pump requires only basic tools to maintain, and can be retrofitted into existing installations where a Mono Compact C pump has been used previously.