Waste Water Treatment

As well as making water clean for you to drink, we’ve also a duty to make the water you use clean and safe to give back to the environment.

That means that the water you bath or shower in, and the water you flush away in the loo, all has to go through a treatment process in one of our 833 waste water treatment sites.

Once it’s there, we remove soapsuds, grit, heavy particles and whatever else we find that may harm the environment. We do this via a range of processes including aeration and sludge treatment.

Did you know?

  • The sewer network in Wales that takes away your wastewater is over 30,000kms long!
  • The overall amount of water on our planet has remained the same for two billion years.
  • Water is the only substance that is found naturally on earth in three forms: liquid, gas, solid.
  • Frozen water is 9% lighter than water, which is why ice floats on water.
  • Over 90% of the world's supply of fresh water is located in Antarctica.

Let's Stop The Block

Welsh Water needs your help! Flushing items like nappies, wet wipes and cotton wool balls down the toilet and pouring thing like fat, oil and grease down the sink, can cause BIG problems. It can lead to blockages in your house, flooding in your street and pollution in your neighbourhood.


Poo Power

It’s hard to believe that wastewater and sewage could be used to light our homes, we call this Poo Power!

Poo Power uses a biogas rich in methane which is removed from the treatment of wastewater and sewage to drive the turbines. The biogas, predominantly comprising of methane, is produced when bacteria feed on human and animal waste. This process is known as anaerobic digestion and it is a great way to produce green energy, as well as getting rid of waste and the micro-organisms that lurk in it. One of the simplest ways of describing anaerobic digestion is the ‘farting’ of millions of tiny bugs within the waste, which produces the biogas.

Positively, when the biogas is burnt for generating electricity far less carbon dioxide is released than when fossil fuels are burnt.

Did you know?

  • It takes the poo of 100,000 people to generate 51kW of electricity, enough for 500 light bulbs.

Downloads and information:

If you’re keen to learn more about waste water treatment, why not visit us at one of our discovery centres.

Waste water maze

Waste Maze

Mia has to fill the gaps in the pipes. Can you work out how many of
each type of pipe she needs to complete the job?
Get the maze
Waste Water Process Thumbnail

Wastewater Process

PDF, 227.7kB

Download the Wastewater process and discover how your wastewater is cleaned.