Audley and Alsager Waste Water Treatment Works

Audley and Alsager were recently installed on wastewater tertiary treatment to assist our customer United Utilities with meeting their new incoming AMP 7 permit consents. As part of the ever growing water quality drivers from the Water Framework Directive, Audley and Alsager were selected to have a low phosphorus permit. To ensure this permit could be reliably met going forward, Evergreen were brought in to install cloth filters for tertiary solids removal.

The cloth filter is the ideal tertiary solids removal process for bringing the suspended solids in the final effluent to <10mg/l, whilst removing the associated phosphorus and metals in the solids through the backwash route. These total phosphorous permits vary from 1mg/l to as low as 0.2mg/l, which the cloth filter has demonstrated time and time again to achieve. Even though the cloth filter is a solids removal process, if the phosphorus is precipitated into a particulate form, by typical conventional metals dosing, then we can be confident that this fraction can be removed in the backwash route and then transferred into the sludge.