How the treatment works operates

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Our treatment works takes water from the tidal part of the River Thames, which is a mixture of salty and fresh water.

How the treatment process works

We begin by taking a mixture of salty and fresh water from the tidal River Thames, then treat it using various cleaning and filtering processes, as used in all our treatment works.

We remove the salt using a process called reverse osmosis. This involves forcing the water at high pressure through very fine membranes, which hold back the salt and other molecules.

The treated water is then re-mineralised so that it has similar properties to other local supplies.

Following this, we purify the water to ensure it is safe to drink, before putting it into our supply network.

Watch a short film about how we designed and built the new works

How often is the plant used?

We anticipate only using the works at full capacity during periods of prolonged low rainfall - typically during a drought.

This is likely to be the only time when some households receive all their water from the Thames Gateway works.

When working at full capacity, the works is capable of supplying 150 million litres of water per day - enough to supply about one million people or 400,000 households.

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Why does London need more water? Frequently asked questions