Standard content for Members only

To continue reading this article, please login to your Utility Week account, Start 14 day trial or Become a member.

If your organisation already has a corporate membership and you haven’t activated it simply follow the register link below. Check here.

Become a member

Start 14 day trial

Login Register

Thames upgrades Victorian sand filters

Thames Water has upgraded two slow sand filter beds at a water treatment site to produce one third of the capital’s water.

Supply to London was maintained while the work was completed at site over the past year.

The slow sand filters are a multi-layered biological filtration system that use an active biological layer formed on the surface called a schmutzdecke.

The schmutzdecke layer provides effective purification and the underlying sand provides support medium for this biological treatment layer.

The sand filters are routinely inspected every 10 years and taken out of service for regeneration every three. This involves removing the multiple layers of sand, granular activated carbon and shingle for washing using a team of 14 technicians.

The treatment process at Hampton includes 32 rapid gravity filters, ozonation and 25 slow sand filters followed by disinfection.

The site in Hampton, which was built in the 1850s, processes up to 700 million litres of water each day making it one of the largest in Europe.

In 2019 the company completed the upgrade and expansion of its wastewater treatment facility at Deephams without interrupting service for its customers.