As part of a scheme to improve local drinking water supply resilience, Veolia Water Technologies UK (VWT UK) has worked with one of the largest English water companies to design and implement three Actiflo® Turbo high performance water clarifiers for treating various types of raw water.
The water treatment works, which serves a large urban population, had been using Dissolved Air Flotation (DAF) and a Rapid Gravity Filter plant to treat relatively clean and soft water sourced from a reservoir. However, it became clear that the reservoir, which was built over 100 years ago, would now require regular maintenance and the intention was to source raw water from a major river nearby during these times. As the existing water treatment solutions were not suitable for river water, the water company required an alternative clarification solution to maintain its high-quality drinking water supply.
As a trusted supplier of water treatment solutions, including for many municipal water companies, VWT UK was approached by an independent consultant to propose a solution. Following an evaluation of the requirements, including the limited space on site for a new plant, VWT UK recommended its Actiflo® Turbo clarifier technology. Actiflo® utilises a polymer coagulant with microsand to ballast the chemical flocs, significantly increasing the settling velocity of the particles. This delivers very short retention times and a more compact design. In fact, the footprint of an Actiflo® system is as much as 40 times smaller than conventional clarifier systems.
The Actiflo® Turbo is the latest development of the technology and incorporates a turbomix shroud for enhanced flocculation. This also removes the requirement for a separate microsand injection and flash mixing tank to reduce the footprint further and deliver savings in both capital expenditure (CAPEX) and operational expenditure (OPEX).
The water needed to achieve strict turbidity, total and soluble iron, UV absorbance, true colour and dissolved organic carbon (DOC) levels to meet the drinking water requirements.
To meet the water companies risk management governance, a long-term trial was established to demonstrate the capabilities of the system, including its effectiveness in treating different raw water types and contaminants. Following a successful 10-month, 2.5 million litres per day pilot study, the water company selected Actiflo® for the upgrade.
Three Actiflo® Turbo streams were designed and implemented, which provided the capacity to process up to 312 million litres of water per day. As the flow range varies significantly between approximately 20 and 104 MLD per stream, VWT proposed three smaller coagulation tanks with variable speed mixers per stream to ensure the stability of the flocc formation under all flow and operational conditions. The Actiflo® system has been fully operational since January 2020.
Paul Cooper, Business Development Manager – Municipal at VWT UK said:
“Our work on this scheme clearly demonstrates the flexibility, versatility and performance of our Actiflo® Turbo technology. It is ideal for large-scale municipal water treatment upgrades such as this due to the speed of treatment and compact plant footprint.”
To find out more about the VWT UK range of water treatment solutions, including Actiflo®, click here
