The Water Treatment Process: More than just a drop.

The Water Treatment Process: More than just a drop. 

Nothing is more important to us than providing you, our valued customers, with clean, safe water.

Freshwater is one of the most precious resources on the planet. It is essential for basic human health, hygiene, agriculture, and industry. However, water is not as abundant as it may seem. Only about 2.5% of the world’s water is freshwater, and of that, a significant portion is trapped in glaciers and ice caps, making it inaccessible. This makes the remaining freshwater a finite and incredibly valuable resource. With this in mind, protecting the purity and security of it is of the utmost importance to all of us at SES Water.  

When you turn on a tap, you probably don’t give much thought to where that water comes from or the complex journey it took to reach your home. Water, for most people, seems like an unlimited resource - falling from the sky, flowing through rivers, and always there when you need it. But the truth is that the process of delivering clean, safe drinking water to your tap involves far more than just collecting rainfall. It requires significant effort, technology, and expertise, all of which we are very proud of. 

Let’s take you on a journey from source to tap. We’ll dive deep into our Water Treatment Process, explore the misconceptions surrounding water availability, and highlight why treating water before consumption is absolutely vital for health and safety. Our goal is to share our love for water and just how much value should be placed on every single drop. 

Understanding the misconception: "Water just falls from the sky".

We know it is very easy, especially in the UK, to have the perception  that water simply ‘falls from the sky’. However, the reality is far more complex.

The journey water goes on before a simple raindrop can become part of your evening cup of tea, is incredible. While rainfall is brilliant for your plants or washing your car, it doesn’t arrive in a drinkable state—it collects pollutants from the atmosphere, and as it lands on the ground, it gathers debris, chemicals, and harmful microorganisms. Even though rivers, lakes, and reservoirs may sometimes look clean to the naked eye, they can be contaminated by everything from agricultural runoff to industrial waste. 

Another common misconception is that the UK’s water resources are evenly distributed. Areas in the South and South East experience water shortages more frequently due to higher population density and lower rainfall. We operate in an area that is classified as ‘seriously water stressed’ by the Environment Agency. This means unless we make some changes there may not be enough water to meet the needs of the environment and our customers in the future, emphasising that managing and treating water supplies is more crucial than ever.

The hidden effort behind every drop of water:

Water Collection: 

To understand how we purify our water, its important to know where it comes from. The River Eden that runs through Surrey and Kent is one of our best kept secrets when it comes to supplying your water. 

Feeding our reservoir at Bough Beech, around 15% of the water we supply comes from this local resource before being treated.

The rest of our water (85%) comes from deep beneath your feet. We’re fortunate to be able tap into natural underground aquifers through boreholes. This is where groundwater is pumped to the surface before reaching our nearest Water Treatment Works. 

Having access to this ground water source has helped us avoid hosepipe bans for over 20 years, keeping your water supply steady and reliable, even during dry spells. 

Collecting the water is just the first step - one that depends on careful management to ensure that water is extracted sustainably, without depleting the environment.

Screening:

The screening process is one of the initial and most fundamental steps in the water treatment process. It’s designed to remove large objects and debris from the water before it enters the more intricate stages of treatment. 

Without this step, larger particles could clog and damage the delicate machinery and filtration systems used in later phases. 

Screening involves passing raw water through physical barriers, or "screens," to filter out large solids. These solids can include a wide variety of items, such as natural debris like leaves and twigs or human-made waste such as plastic or paper. 

We, and many other water companies, aim to manage the debris in an environmentally friendly way, minimising waste and maximising recycling wherever possible. 

Chlorination:

Chlorination is the next step in the process, playing a key role in ensuring that the water supplied to your homes is safe for consumption. By using chlorine, we can effectively kill harmful microorganisms like bacteria and viruses, preventing the spread of waterborne diseases. It offers a lasting protective effect, meaning that some chlorine remains in the water as it travels through distribution systems, continuing to disinfect until it reaches your taps.

After chlorine is injected, the water is held in large storage tank for a period to allow for adequate contact time. The longer chlorine remains in the water, the more effective it is.

Clarification:

Now that we have removed all large debris and chlorinated the water, we are ready to clarify. Clarification is designed to improve the clarity and quality of water by settling out solids and other contaminants. It plays vital role in preparing water for the subsequent steps of filtration and disinfection. 

The process relies on gravity and chemical assistance to allow these particles to settle at the bottom of the tank, leaving behind a ‘sludge blanket’. We add alum to bind the tiny clay particles together into clumps heavy enough to sink to the bottom of the tank. 

The clarified water then continues its journey, while we collect the clay from the sludge blanket and return it to the environment.

Sand Filtration:

Sand Filtration is next, and it plays a key role in improving the quality of the water. It passes through large sand filters, removing contaminants like dirt, debris, and microorganisms that remain after Clarification. 

Filtration improves the taste, odour, and appearance of water by capturing these smaller particles that could potentially make your water appear cloudy, for example. 

Activated Carbon:

We use Activated Carbon as a part of our water treatment process due to its ability to adsorb a wide variety of contaminants, making it a valuable tool in ensuring the water is not only safe but pleasant to drink.

As water passes through the activated carbon, contaminants are attracted to the carbon’s surface and become trapped within its pores. This process is known as adsorption, where particles stick to the surface of a material rather than being absorbed into it. The large surface area of the carbon allows for maximum contact between the water and the carbon, making the process highly efficient.

The activated carbon is also particularly good at removing Chlorine from the water, which can leave an unpleasant taste or smell. 

We give the carbon a thorough backwash every six days, and we renew the carbon through a special process once a year! Your water deserves the best, and we make sure that it gets that.

Ultraviolet Light:

By now we’ve removed as much solid matter as we can from the water, and it is looking clear, but it is not quite ready yet. We use a unique method of adding UV light to further disinfect your water and SES Water was the first water company in the UK to use this method. UV disinfection is a non-chemical process that involves exposing water to ultraviolet light at a specific wavelength.

It keeps your water safe and free from harmful bacteria like cryptosporidium. UV light disrupts the DNA of these tiny organisms, stopping them in their tracks. Some of the benefits of using this method is that it is in energy efficient and does not change the taste, colour or pH of your water. 

THM Towers:

The THM Towers process is an important method in water treatment, focusing on removing trihalomethanes (THMs), a by-product formed when chlorine used in disinfection reacts with organic matter in the water.

The water cascades down over hundreds of plastic cylinders, with air blowing upwards, scrubbing the water clean. As the water contacts the air, THMs and other compounds are transferred from the water to the air, effectively removing them from the drinking supply. 

Treated Water Tank:

The treated water tank is an essential final stage in our water treatment process. Once water has gone through various treatment stages—such as screening, filtration, disinfection, and additional purification—treated water is stored in large tanks for at least 30 minutes before it is distributed to your homes. 

The primary purpose of treated water tanks is to provide a buffer between water treatment and distribution. These tanks ensure there is a reserve of clean, treated water available for periods of high demand or during maintenance on the treatment system. It also helps maintain consistent water pressure in the network. Water stored in these tanks can be released when demand increases, preventing drops in water pressure that can lead to service disruptions.

Our water then becomes your water.

Conclusion: A new perspective on water

Our water treatment process is a highly complex and carefully managed operation that involves significant effort, technology, and investment. From screening and filtration to advanced disinfection methods like ultraviolet light and chlorination, we work tirelessly to ensure that every drop of water delivered to your taps meets stringent safety standards. This process is not just about removing contaminants, but also about protecting our customers from waterborne diseases, safeguarding the environment, and ensuring a reliable water supply in the face of challenges like climate change and aging infrastructure.

Water is a precious resource, and the misconception that it simply "falls from the sky" overlooks the extensive treatment journey it undergoes before it becomes safe for consumption. We are continuously investing in innovative solutions, such as smart networks and real-time monitoring, to optimise water use and reduce waste. By understanding the immense effort required to treat and distribute clean water, we all can better appreciate its value and take steps to conserve it, ensuring that future generations continue to enjoy this vital resource.

Water may seem abundant, but every step in the treatment process highlights the true value of every single drop.