Veolia Water Technologies’ Actiflo® clarification units have been successfully implemented at two wastewater treatment facilities in the South East of England. During a trial period, Actiflo® delivered phosphorus (P) discharge levels as low as 0.03mg/l – exceeding the client’s requirements and providing significant OPEX savings.

Prior to Veolia Water Technologies’ involvement, the twin facilities in the South East were undergoing a general works upgrade to accommodate the rapidly expanding population of the nearby communities. However, both sites required technology that could deliver incredibly low P levels of <0.1mg/l and <0.08 mg/l respectively. These consent levels were required as a result of the treatment works’ discharge into sensitive receiving waters and their proximity to a Site of Special Scientific Interest (SSSI), a Special Area of Conservation (SAC) and a National Nature Reserve.

Veolia Water Technologies ran a performance trial using its Actiflo® technology in order to demonstrate its efficacy. After an eight-week trial period with a mobile unit, the client recorded P discharge levels of 0.03mg/l, conclusively demonstrating the technology’s capabilities.

However, due to limited space and the client’s requirements for a prefabricated solution, any chosen technology would need to be compact and craned into position. The Actiflo Turbo® range has the advantage of being 5 to 20 times smaller than other conventional clarification units of a comparable output thanks to its utilisation of microsand for ballasted flocculation. This further solidified its suitability for the application and the units were specified for each site.

The final configuration at the site requiring less stringent P removal included two Actiflo Turbo® AS3 clarifiers with a flow to full treatment (FFT) of 123 litres per second. For the other site, four Actiflo Turbo® AS5 clarifiers were specified to treat an FFT of 489 litres per second. The patented Actiflo Turbo® process generates an enhanced flocculation zone, allowing it to produce water high-quality treated effluent.

Both sites also utilise Veolia Water Technologies’ ferric sludge reuse system, leading to significant OPEX savings. This was implemented after chemical analysis during the performance trials, enabled by their digital monitoring system Hubgrade, which showed that the sludge was still sufficiently active to provide coagulation. The sludge at both sites is therefore recirculated, removing the need for a secondary dose of coagulant and making significant ongoing OPEX savings possible.

Paul Cooper, Business Development Manager at Veolia Water Technologies commented: “We are very pleased that the installation of the Actiflo® TSR system has been such a success. Actiflo can reliably achieve the lowest P levels of any technology in the UK, a fact we have demonstrated at these two facilities.

“As water consents continue to tighten the need for optimised technology, such as our Actiflo® system, increases. We are proud to be spearheading this technological innovation and look forward to continuing to work closely with the site and gain further insight into how to optimise our technology.”

To find out more about Actiflo® and Veolia Water Technologies’ range of solutions, visit