Client: Clissold Leisure Centre   Location: Hackney, London.   Completion date: October 2023

Clissold Leisure Centre has three pools – two 25 metre pools (one Main and one Training) as well as a Toddler Pool for children aged 5 years and under. The Training Pool features a movable floor which can adjust the depth of the pool from 0 to 1.5 metres for an ideal learning environment.

The Challenge

The clarity of water was, on occasion, causing the Main Pool’s underwater anti-drowning camera protection system to trigger false alarms. Centre Manager, Martin Young, contacted Sterling for a cost-effective solution.

The existing filtration system for the main pool consisted of two 2.6m diameter sand filters operating at 20m/h, with a pool water turnover of around 4 hours.

Sterling’s Solution

Sterling carried out direct replacement of the sand media in the two filters with AFM® Activated Filter Media.

AFM is a highly engineered filter media manufactured from Dryden Aqua from recycled green and brown glass. The glass is activated in a three-stage chemical and thermal process which modifies the surface. Activation increases the charge on the surface and makes it hydrophobic (water-repellent).

AFM achieves filtration to 1µm (95%) and removes 50% more organic substances from the water than sand and other glass filter media, reducing the formation of harmful THMs including chloroform.

It is also self-sterilising which prevents the biological growth in the filter bed which can lead to both channelling and biological conversion of urea to ammonia which is responsible for toxic chlorine smells (trichloramines).

Project Success

Upgrading the filter media from sand to AFM resulted in a 63% reduction in phosphate in the pool water and 60% reduction in combined chlorine (see table below):

“The improvement in water clarity was immediate and, over the last few months, we’ve seen a reduction in chlorine consumption. We’re absolutely delighted."

— Marc Scott, Executive Officer