Spotlight on PIERdek

A Sustainable Approach to Improving Wastewater Treatment Performance and Productivity

United Utilities


2H Water Technologies helped United Utilities improve productivity and reduce environmental impact at the company’s wastewater treatment plants in Crewe, Cheshire and Cockermouth in Cumbria.


United Utilities, which collects and treats wastewater and industrial effluent from three million private users and 200,000 businesses across North West England, is at the forefront of  “green innovation” initiatives which aim to find sustainable solutions to the industry’s most pressing challenges.


This commitment to sustainability has underpinned the company’s approach to upgrading many of its 500 plus wastewater treatment plants.  In recent years, United Utilities has invested over £1 billion in a variety of projects each of which is designed to maximise operational effectiveness at the same time as minimising environmental impact and enhancing local wildlife habitats and biodiversity.

Boosting Performance, Reducing Environmental Impact


2H Water Technologies was commissioned by main contractors, LIMA (Laing O’Rourke and Imtech, with support from Atkins), to manufacture and install BIOdek structured plastic media and a recent addition to the 2H product portfolio, PIERdek media support systems in three nitrifying filters – two existing and one new – at United Utilities’ wastewater treatment plant in Crewe, Cheshire.   2H also supplied a variable speed rotary distributor in the new nitrifying filter.


The £2.8 million contract was part of an initiative to boost overall performance at the Crewe plant and meet tighter consents particularly with regard to chemical levels, notably ammonia, that can be discharged in outflows to rivers.


The project also required 2H to remove the old PVC plastic media from the two legacy nitrifying filters  – which was then recycled – prior to installing a more sustainable and effective alternative, BIOdek polypropylene (PP) cross-flow, structured plastic media.


In total, 2H Water Technologies designed, built and installed 13,760m3 of BIOdek media across three nitrifying filters.

New Media, New Support System


2H was tasked with replacing ageing concrete block media support structures used in the two established nitrifying filters, each of which was showing signs of erosion, with custom-built PIERdek media support systems.


PIERdek is ideal for use with corrosive wastewater, for example, in nitrifying filters where alkalinity can corrode masonry support structures.  Whatever the water quality, PIERdek will provide the same exceptional and reliable performance even after long-term use.


PIERdek is not only more durable but also more adaptable than structures built from concrete or masonry.

Because both the nitrifying filters used built-in ventilation fans to provide forced air beneath the media there was a larger than average gap between the media and floor.  Our design team created a PIERdek system which used heavier duty uprights and components to duplicate the existing support structure’s height of 1.8m and so maintain the hydraulics of the infeed system.

Cockermouth, Cumbria


2H Water Technologies was involved in another successful United Utilities upgrade project at Cockermouth in Cumbria.  In this case, 2H was contracted by LIMA to build two roughing filters capable of treating crude BOD directly without primary settlement – from 166mg/l down to 37mg/l.


2H provided an end-to-end service which resulted in the creation of two new roughing filters measuring 12.8m diameter x 6m bed depth.  The scope of work involvded 2H designing, building and installing 2 glass lined steel tanks, a splitter flow tank, access platform, 2 Equiflo variable speed rotary distributors, PIERdek media support  and a total of 1,546m3 of BIOdek cross-flow structured media across the two roughing filters.


As contract negotiations were underway, 2H was asked to supply an alternative to the traditional concrete block/lintels media support system.


Because it’s manufactured from durable, chemical-resistant plastic, PIERdek meets United Utilities demands for a media support structure capable of operating effectively in acidic water.


And because the filters – and therefore the media – would be installed on a sloping floor, 2H designed a PIERdek system that could be installed on a gradient and still present a horizontal support for the Biodek media.