Behind the scenes at Bray's water treatment works

Grace Witherden


When you turn on the tap for a drink, or jump in the shower, it’s probably not often you think about where the water has come from, or how it was made safe for your consumption.

It’s not something I had thought about much either until I had the chance to visit the Bray Keleher Water Treatment Works.

The site in Monkey Island Lane is run by South East Water, which supplies drinking water to 2.1 million customers in Berkshire, Surrey, Hampshire, Sussex and Kent, and treats 30 million litres every day.

I’m first shown around the control centre by Sara Best, who is the regional process manager for the company.

It’s hard to imagine a site this big is tucked away in Bray, providing drinking water to thousands of houses, 24 hours a day, 365 days a year.

The £22 million treatment works was built in 1993 and supplies 126,000 properties with water via two reservoirs, one in Swinley Forest (Surrey Hills) and one in Crowthorne.

Water is pumped from the River Thames and undergoes ‘pre-ozonation’, where gas is diffused through water to break down organic pollutants and help with the treatment of algae.

Stage two involves a chemical being added to the water which makes tiny particles in the water stick together, which can then be removed – this reduces the cloudiness and improves the colour of the water.

“Most people don’t realise, but drinking water has to meet much higher standards than water from a bottle, people just assume that bottled water is better,” Sara says.

As we walk up the steps, I can see the water tanks beneath my feet and hold tightly on to my keys – I wouldn’t want to drop those down there.

We walk across a bridge which brings us to stage three. During this process, the larger particles stick together to form a ‘solid sludge blanket’ and the clear water rises upwards.

The water is then filtered through gravity filters containing sand. This removes any last particles from the water, which is then treated with ozone gas and passed through more filters.

We walk up to a building where the water is treated with ultraviolet light, killing any remaining bacteria, before the water enters a contact tank where it is treated with chlorine. An extra amount is added to make sure the water remains bacteria free when it is pumped through giant pipes straight to the customers’ taps.

The water also goes through a de-chlorination stage where the chlorine level in the water is reduced to make sure the taste of the water is right.

“We do sometimes get customers ringing up and saying their water doesn’t taste right and it’s usually because of the chlorine level,” Sara explains. “We have to alter the amount daily and we have water testers based in Farnborough that will take samples every day from reservoirs, boreholes, customers’ taps and businesses.

“In fact they even work on Christmas day, so if you have a knock on your door from someone asking to sample your water, you know why.”

My visit also includes a look inside a noisy building where water is pumped to the Surrey Hills Reservoir using giant pipes – I am handed ear plugs for this stage.

As I say goodbye to the team, I think about how much water they treat every day, and how lucky we are to have access to clean water.

I know I’m guilty of taking it for granted.

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