EFFICIENT AND INNOVATIVE
Hanningfield Water Treatment Works in Essex treats about 225 million litres of water a day from Hanningfield Reservoir to supply drinking water to a large part of Essex and also Southend, Thurrock and the London Boroughs of Barking, Dagenham, and Redbridge.
But it’s also home to an unusual World’s first.
Water that comes out or a reservoir contains silt and algae so an early stage of cleaning water to deliver to customers involves separating them from the raw water. At Hanningfield this process creates up to three million litres of a liquid sludge, every day. The vast majority of this sludge is water.
In a world first, after several years of research and large scale trials, Essex & Suffolk Water found a way to treat this water sludge using a natural reed bed system. Reed beds have been used successfully for many years in sewage treatment and food applications but never before in the water treatment process.
The beauty of using the reed beds is that the system naturally recycles the valuable water from the sludge without mechanical or chemical processes that need a lot of maintenance and power to run. Using these reed beds is much better for the environment and saves 70 tonnes of greenhouse gas emissions a year compared to the traditional systems.
The 16 reed beds, cover more than ten acres and are the first reed beds of their kind in the world and the first we’ve ever used in our drinking water treatment process. This innovative system is a big step forward in ensuring that we produce clean, clear water that tastes good in the most sustainable way possible and demonstrates how we are leading the way in the water industry.
Using the reed beds natural process to recycle the valuable water from sludge is great news for the environment and our customers as we use far less energy and chemicals. As well as the clear environmental benefits, the system is also far more cost efficient in the long term than the traditional mechanical option saving our customers money.
The reed beds are also attracting a variety of wildlife, including invertebrates, birds and foraging bats. They also provide a water supply for the disused sludge lagoon the reed beds replaced, within the site of special scientific interest, which we’ve successfully restored as a wildlife-rich mosaic of reed bed, open water, wet scrub and woodland.
How do the reed beds work?
Each reed bed is a highly efficient and sustainable filter system which is loaded with liquid sludge on to its surface. The sludge then passes through the filter by gravity. Any solids in the sludge are left as residue on the surface of the bed, while clear, filtered water continues to pass through to a drainage system at the bottom and returns to the reservoir. The process is entirely natural with no fertiliser or chemicals.