Water quality matters
Welcome to the final chapter of Water Quality Month. This week, we are turning our focus on a grown concern within the media affecting our waterways: CSO spills.
Did you know that SuDSPlanters play a crucial role in reducing CSO spills and improving water quality? By capturing roof water runoff and slowing the flow into our sewers we are reducing CSO spills and filtering rainwater This helps to create capacity in sewers and a healthier environment for everyone. ??
Our team is passionate about addressing the broader impacts on water quality, including those from agriculture and highways. ?We actively sit on several industry working groups to advise on those subjects and work to finding solutions. Our focus since the start has been to support the reduction in CSO spills, so improving water quality across all our rivers and seas.
The Combined Sewer Overflow and why it exists
The UK has a combined sewage system made up of hundreds of thousands of kilometres of sewers, built by the Victorians to convey waste water from toilets, bathrooms and kitchens and clean rainwater in the same pipe to a sewage treatment works.
Combined sewer overflows (CSOs) were developed as overflow valves to reduce the risk of sewage backing up during heavy rainfall. These are a necessary part of the existing sewerage system to prevent sewage from flooding homes and businesses.
However........ Climate change, human behaviours and maintenance are one of the many reasons why the social media focus on CSO spills is increasing, and why this forms the final chapter of our water quality month campaign.
CSO Spills
o?? This data includes information on the frequency and duration of overflows.
o?? The agency has publicly expressed concern about the high number of overflows.
So what causes a CSO to spill?
Blockages - Recently we published an article on National Toilet Paper Day, discussing the topic of #StopTheBlock . This looked at one of the many reasons CSO spills occur, which includes blockages caused by unwelcome extras being put down our sewers in addition to the 3 P’s.
These blockages cause the sewer to struggle with passing through the flows of wastewater, Pee, Poo and Paper (toilet) on to the treatment works. When this occurs CSO’s are designed to kick in and reduce the risk of sewage backing up into people’s homes and flooding out through our toilets.
In addition to blockages the increasing volume of water entering sewers has created even more pressure on our pipes, here are a few reasons why we have more water entering our wastewater system;
Ageing assets – our sewers can date back as far as back as the 1850’s. In some of our towns and cities the original sewers are still used as a means to transport wastewater to the sewage treatment works used to turn sewage into a clean water supply which can re-enter the environment without causing harm to our rivers and seas. Decay and damage to these assets can cause water to ingress into the sewers, adding to the flows needing to be transported through the system.
Increased hard standing in urban areas – As we expand our living spaces and pave over gardens to create extensions, patios and parking areas these impermeable areas are being tapped into the sewer. When it rains the increased flows put additional pressure onto the sewers, increasing the flows generated by the population density of the area. Did you know the majority of sewer systems in urban areas pre 1970 are ‘Combined’. These take flows from our sinks, showers and toilets, downpipes, paved areas and surrounding highways, as well as some watercourses historically piped underground to make space for people to live. ?
Increased water use - Over a fifth (21%) believed their household uses 19 litres or less, which is only enough to flush the toilet twice.??In reality, each individual person in the UK uses an average of 152 litres of water per day, and the demand for water has been increasing since the pandemic as people spend more time at home.?These flows are entering our sewers regardless of what the weather is doing outside. By reducing flows into the sewers from our homes, we are making space for more challenging water sources to be accommodated when the weather turns bad.
?Climate change - The country is experiencing more frequent and intense extreme weather events, such as floods and droughts, which are placing increased pressure on water resources and infrastructure. Climate change is also affecting water quality and availability, as rising temperatures and changing precipitation patterns alter the water cycle. These pressures affect the environment by depleting habitat value and making water quality more challenging to deliver with potential pollution sources from agriculture, highway runoff and water companies being realised when heavy rain mobilises pollution sources.
SuDSPlanter Ltd’s call to action;
So what can we do to help support the reduction of CSO spills across our sewer network. The environment is changing, and so is the water industries attitude to manage surface water entering our sewer network. Approaches such as; ‘Slow the flow’, SuDS for Schools and Clean Rivers and Seas are a few of the campaigns looking to embrace ‘Sustainable drainage’ as a means to disconnect surface water generated by downpipes, highway runoff and surface water runoff from impermeable areas entering the sewer system. By creating capacity in the sewer during rainfall events we can move wastewater through to its rightful place ‘the wastewater treatment works’ without relying on the CSO’s to ensure homes and gardens don’t flood along the way.
In Sudsplanter we pride ourselves on working towards reducing clean water flows reaching our sewers when they are at capacity, due to the increasing rainfall events we see with today’s climate. SuDS systems, including SuDSPlanters, can significantly reduce stormwater runoff volumes. ?However, the exact percentage reduction depends on factors like the system's design, location, and rainfall intensity. ?
The benefits of using SuDS include;
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By attenuating the water on site SuDS systems are designed to slow the flow into the sewer, so creating space for the sewage without needing CSO’s to spill during rainfall events.
However, taking surface water out of the sewers is not the only way to minimise the risk of a CSO spilling.
In addition to this you could also look to reduce water consumption by taking shorter showers, use water saving devices within white goods and fix leaks on taps and toilets within the home and public / work settings. ( Public perception of how much water is wasted through leaks in the home found that over half (61%) of the public thought that a faulty toilet flush wastes less than 50 litres, when it actually wastes between 215 and 400 litres per day!)
Finally, it’s important to remember only flush the 3’ P’s (Pee, Poo and Paper). Wet wipes make up more than 90 per cent of the material causing sewers to block, ensuring unwanted items don’t enter our sewers can help support the reduction in CSO spills, and support water companies in reaching their target of reducing their storm overflow spill target to less that 20 spills per overflow by 2025.
If you have any good examples of Sustainable Drainage Systems illustrating why collectively we must work together to drive positive change across the board please do feel free to share! ?