The UK’s wastewater network is vast – long enough to wrap around the world 14 times. Every day, sewers and drains collect over 11 billion litres of wastewater. This is treated at 9,000 sewage treatment works before clean water is discharged to inland waterways, estuaries, and the sea. By removing solids and other pollutants, wastewater management prevents harm to human, animal and plant health. At least that’s what should be happening…
The reality is that sewage overflow discharges more than doubled between 2022 and 2023, with 3.6 million hours of spills in 2023 compared to 1.75 million the year before. Solving sewage discharges is one of the most urgent challenges facing the water sector.
Marc Hannis Photo credit: University of Sheffield.
The problem is intensified by several factors. Average rainfall in the UK has increased in the last 60 years as a result of climate change and will continue to do so, leading to more intense storms, which frequently overwhelm the network. The UK population is predicted to reach 74 million in 2036, up from 68 million today. With the Government pledging to build 1.5 million new homes by 2029, outdated wastewater infrastructure – much of it built in the 19th century when there were far fewer people – will find itself under additional pressure, increasing the risk of sewage discharges further.
Business as usual approaches will not be enough to solve these challenges. Sewage discharges are the product of multiple failures across the whole wastewater management network. It’s not a case of only targeting the point of discharge, we must deploy solutions across the entire system, so that mechanisms to prevent the wastewater network becoming overwhelmed are in place at all upstream points.
The water sector must develop and implement innovative wastewater management solutions to tackle sewage discharges head on.
To propel innovation in the water sector, the Ofwat Innovation Fund has awarded more than £150m to more than 90 collaborative innovation projects since 2020, each developing solutions to the biggest challenges facing the sector, including how it transforms the management of wastewater.
To ensure the whole sector benefits from and builds upon the lessons of these projects, a key mission of the fund is to share knowledge openly and widely, including in learning reports. The latest of these focusses primarily on innovation for water conveyance systems, which transport wastewater from collection points to treatment facilities and then on to disposal or distribution.
One innovative wastewater management initiative is The Artificial Intelligence of Things Enabling Autonomous Waste Catchments project, which looks to pilot the use of artificial intelligence (AI) to monitor a waste catchment area in real time, minimising the risk of flooding and sewage pollution. By rapidly identifying anomalies and predicting potential issues across the catchment area, the technology can identify where there are parts of the system that are becoming overwhelmed. Upstream flows can then be held back and released later, so that the system can use all the capacity that is available. One of the aims of this initiative is to develop a scalable and shared blueprint that can be widely adopted across the water sector. Once completed, a full report from this project will contain its results and conclusions, so that learnings can be embraced by others to optimise their sewage catchment management.
Pipebots for Rising Mains, from the University of Sheffield in partnership with Thames Water, is developing robots that operate inside pressurised wastewater pipes that transport sewage uphill. While not directly addressing overflow discharge, another technology being developed aims to prevent other harmful pollution events. These robots can identify, predict and address failing pipes, preventing bursts and harmful pollutants from spilling out. The project aims to transform the water sector’s approach to maintaining pressurised sewer infrastructure and enhance its monitoring and maintenance in difficult environments. The project has shown that there is great potential for new sensor and robotics technologies, despite some technical challenges that the team is working to overcome in the design and operation of the robots.
The way the network manages wastewater must change – especially as customer bills are rising to fund significant investment in the wastewater network. Innovative approaches to preventing sewage pollution such as these need to be nurtured, as a business-as-usual approach will not achieve the lasting impact that customers demand.
In its first five years, the Ofwat Innovation Fund has endeavoured to support the adoption and testing of new initiatives for the sector, and with those projects completed or well underway, it’s critical that knowledge and insights that they have gathered are shared openly.
The fifth Water Breakthrough Challenge is in motion and will name winners in the Spring, taking the total of disbursed funding to £200m. Beyond this, we have announced that for 2025-2030, the fund will double in size to invest a further £400m in water sector innovation. We hope to see more water companies come together to implement some of these innovations, tested through the Fund ensuring that these nascent technologies and approaches are implemented at scale in the future.
Read the new learning report, ‘Rethinking Wastewater Systems: new approaches for wastewater networks’, at waterinnovation.challenges.org/insights
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