The Kingstone and Madley Waste Water Treatment Works, managed by Welsh Water, was originally built in the late 1940s and was modified to keep up with the growing local population.

In the late 1980s, four horizontal flow reedbeds were added to the system to provide additional treatment before discharge into a nearby watercourse. These reedbeds have performed well and continue to operate, reliably meeting discharge standards. However, due to ageing and increased demand, the reedbeds have lost some of their treatment capacity, leading to inefficiencies during the process.

With the local population expected to grow further and discharge regulations becoming stricter, Welsh Water reviewed the entire treatment process to ensure it could handle the additional load. A complete site refurbishment and filter replacement was planned, and Welsh Water asked ARM Ltd to explore options for upgrading the existing reedbeds, focusing on refurbishment rather than replacement.

The reedbeds handle an average daily flow of 332m³, with peak flows reaching 16.6 l/sec.

After a site review, ARM Ltd determined that by using Forced Bed Aeration™ (FBA™), only two of the four existing reedbeds (covering about 1500m²) would be needed to treat the post-refurbishment load to the required standards. The selected beds were in poor condition and needed complete refurbishment, including replacing the liners, adding new media, updating the distribution and collection systems, installing duty/standby blowers, and converting the beds from horizontal flow to vertical flow operation.

The new system was designed to work with the existing upstream processes, which include a primary settlement tank, refurbished trickling filters, and a humus tank. Effluent from the system is now directed into a new chamber that feeds into the upgraded reedbeds.

ARM Ltd completed the project in just four months, keeping the site operational throughout to ensure continuous wastewater treatment. The new FBA™ reedbed system at the Kingstone and Madley site provides Welsh Water with a reliable, high-performance tertiary treatment solution, ensuring long-term compliance with discharge regulations.

The beds that weren't refurbished can be used for extra capacity if needed, and the option remains to refurbish them in the future.