Errol Scotland WWTP

For the Errol project, siting the project did not require consideration of access roads for sludge lorries due to the uniqueness of the Aero-Fac® system.

Client: Scottish Water
Date: Tuesday, 14 August 2001
Info: Remote mostly automated WWTP for small village

Errol city

Visitors to the Errol plant are typically amazed by the lack of odour. Many remark that it is hard to believe that they are at a sewage treatment plant.

The Aero-Fac® treatment system incorporates a number of highly unique features, not least of which is the self digesting sludge process that requires no pre-screening, sedimentation tanks or clarifiers, no sludge removal, dewatering or conditioning, and best of all, no routine sludge disposal and the associated lorry traffic in and out of the works. All sludge is continuously self-digested within the initial treatment stage.

errol specs 1


North of Scotland Water (NoSWA), the Scottish water agency at the time of construction, had implemented a fast, innovative and economic solution for treating the wastewater from the community of Errol on the scenic Tay estuary near Dundee, Scotland. The innovative Aero-Fac® approach provided cost and environmental benefits that came to have implications for wide application across the rest of the UK. 

An analysis of various options demonstrated a remarkable cost advantage for the Aero-Fac® option in both immediate CAPEX as well as ongoing OPEX.

Following construction and commissioning of the new wwtp, the effluent from Errol routinely met rigid European requirements. Most importantly, it did so without the production of sludges requiring costly handling and highly-regulated disposal.

By adopting a highly sustainable system with a completely biological process, very little in the way of mechanical equipment, operational manpower or energy  has been needed for routine operation of the plant, thereby meeting the then needs of NoSWA in providing affordable public services. The well-proven technology provided reliable process control to achieve quality of effluent with low capital and exceptional flexibility.

An independant long term study of the Aero-Fac® plant at Errol commissioned by Scottish Water and carried out by the University of Leeds, confirmed the performance of the system. In the final report, particular mention was given to the plant's class-leading disinfection performance together with its ability to destroy 99.99% of the solids entering the system.

errol layout

Errol is a good example of just how good a neighbour an Aero-Fac® plant can be! No odours. No sludge lorries. No noisy mechanical equipment. The Errol wwtp routinely processes the community's wastewater with little operator attention and is an attractive facility that fits within its sensitive environment.

errol effluent

Errol filled  Errol difuser construct