The UK collects over 11 billion litres of wastewater, or sewage, every day. This includes water from sinks, toilets, baths, showers, industrial wastewater, and rainwater run-off. Without the correct treatment, this wastewater would have negative impacts on both the environment and public health.

Have you ever wondered what happens to the water that swirls down your drains every day? Aqua Rod South West Ltd provides the answers you’ve been looking for with this step-by-step explanation of the UK’s sewage treatment process.

Step 1: The sewer network

Firstly, water that drains out of your home is carried to a communal sewer pipe, which runs under our roads. This sewer pipe then joins a network of other sewers and takes the water to a sewage treatment works. It is here that the cleaning and filtering process takes place.

Step 2: Screening

This stage involves removing various objects that could block or damage equipment, or pollute our rivers if they were to make it that far. Large objects are removed first, including items such as nappies, wet wipes, sanitary items, and even bottles. Specialist equipment is then used to remove grit and other smaller contaminants.

Step 3: Primary treatment

At this point, the wastewater still contains what is politely called ‘organic solid matter’ – human waste, in other words. This is separated from the water using large settlement tanks, where solids sink to the bottom to become what’s known as ‘sludge’. Large scrapers push this sludge towards the centre of the tank so it can be taken away for further treatment. Sludge is ultimately used as fertiliser or to generate energy. The remaining water passes over a wall near the top of the tank and makes its way to the next stage of treatment.

Step 4: Secondary treatment

The visible bits of sludge may have been removed, but smaller and sometimes invisible organisms will still be present in the water. To remove these, the wastewater is put into rectangular tanks called ‘aeration lanes’, which pump air into the water. This encourages useful bacteria to break down and eat harmful bacteria. The useful bacteria grow and multiply as they eat until eventually all the harmful ones are eliminated.

Step 5: Final treatment

The treated water is then passed through a final settlement tank, where the useful bacteria sink to the bottom. This forms more sludge, which is recycled back to the secondary treatment stage. The clean water is then passed over the wall near the top of the tank once again. At this point, it is sometimes filtered slowly through a bed of sand to catch any remaining particles.

Step 6: Return to nature

Once the water is clean, it can be safely returned to lakes, rivers and streams, which helps keep water flowing and wildlife thriving. The quality of this water is rigorously monitored and tested to ensure it meets safety requirements.

Pipes and drains are a crucial part of the water cycle, so you need to ensure yours are given the care and maintenance they need to stay in great condition. From routine maintenance and cleaning to repairs and installation, Aqua Rod South West Ltd are on hand to help with all your drainage needs. Contact us today to find out more.

Published by: David Parkes on: March 22nd 2022