Improving water quality in the River Wharfe

Ilkley Wastewater Treatment Works Upgrade

The River Wharfe at Ilkley was the first stretch of river in England to receive inland bathing water designation. Yorkshire Water asked our team to create the outline designs for the wastewater treatment works upgrade.

We used our Hydraulic Analysis and Design System (Hades) to help design the £45 million upgrade of Ilkley Wastewater Treatment Works. Hades helps engineers understand the hydraulic response of water through water and wastewater treatment works, so they can design systems that work reliably by modelling real-world conditions.

First, we built a model in Hades of the existing works from drawings and surveys. This helped us identify bottlenecks and areas of spare capacity, allowing us to make best use of existing assets and reduce the amount of new infrastructure required by retaining elements such as the inlet works.

As we further developed the design, we expanded the Hades model to include new process units, primary settlement tanks, a new storage tank, and interconnecting pipework. Hades can be used to model complex wastewater treatment works features such as side weirs, flumes, pumps, screens, sluice gates, and settlement tank launder channels. Where flows split in the wastewater treatment works, our team used Hades to solve the flow routing calculations. We also used it to confirm pipe and channel sizes and test system performance under different maintenance, roughness, and flowrate scenarios within the same model.

The upgrade includes a new 17,000-square-metre (182,986-square-foot) integrated constructed wetland (ICW) to naturally treat water during heavy rainfall before it’s returned to the River Wharfe. We also used Hades to model the ICW connecting pipework, channels, and weirs.

These improvements will more than double the site’s treatment capacity and significantly cut the frequency and duration of storm overflows into the River Wharfe, allowing the designated bathing area to be extended.