There is no silver bullet to wastewater sustainability – bold thinking is essential

Marc Hannis, Principal of Ofwat’s Innovation Fund, outlines the challenges surrounding wastewater management and explains how we can ensure sustainable solutions moving forward.

The wastewater network in England and Wales could wrap around the equator 13 times. It is vast and complex, in constant and heavy use, and the subject of several challenges when it comes to sustainability.

Part of the complexity is that wastewater is not one thing. It is a general term that captures everything from sewage effluent generated by homes and businesses to run-off from fields and farms, and rainwater captured by drains (along with anything it might wash away with it).

The wastewater management network in England and Wales serves more than 50 million people and collects 11 billion litres of wastewater a day. It must be adapted to serve a growing population. It needs to be able to handle increasingly extreme weather events, where it is subject to more severe droughts and more intense storms. It needs to change how it operates to reduce its own energy emissions as the economy transitions to net zero.

When we talk about sustainable solutions to the different challenges in wastewater, we not only need to think of it in terms of environmental sustainability, but also how we sustain a level of service that the entire country is reliant on for the long term.

Out of sight, out of mind

In our lives, very few of us ever need to give much thought to wastewater. A toilet is flushed, a bath is emptied, rainwater runs along the gutter and into the sewer – and that is it, out of sight and out of mind.

The public are rightly concerned when problems in drains and sewers bring ‘out of sight – out of mind’ wastewater to the surface. This could be effluent spills caused by increasingly intense storms. Intense rainfall can overwhelm the capacity of the wastewater network and, to prevent wastewater backing up into people’s homes or their streets, sewage is diverted into streams, rivers, and the sea. Such spills could, however, be because the companies have targeted their cleaning and maintenance on the wrong sewers.

It could be the consequences of those spills – such as the ‘wet wipe island’ on the banks of the River Thames, or mass deaths of fish and other wildlife in precious ecosystems.

It could be the consequences of flooding caused by a system unable to transport storm water fast enough – whether that be traffic chaos in city centres and damage to private property, or landslips next to key infrastructure, like railways.

Or it could be agricultural run-off into streams, causing algal blooms that sap the life from aquatic ecosystems, or the result of coagulated fats, oils and greases forming ‘fatbergs’ and completely blocking sewers.

When the wastewater management system works well, we barely notice. When it does not work well, the consequences for people and the environment are hugely damaging.

Last year, Ofwat penalised water companies £150m,  including for pollution incidents and internal sewer flooding. Ofwat is currently investigating how every wastewater company manages its sewage treatment works. Thames Water launched its new app showing real-time data of the scale of the problem of wastewater discharge into rivers across the Thames Valley. This has brought particular media and public scrutiny on the company in recent months.

But it is not only these more well-known problems that pose a threat to the long-term sustainability of the sector. Wastewater transport and treatment is energy intensive – and the production of this energy can contribute to climate-damaging emissions. The water sector is estimated to use nearly 3% of energy produced in the UK (across mains water and wastewater), while removing chemicals such as ammonia from wastewater currently produces greenhouse gasses like nitrous oxide – a gas 300 times more potent than CO2.

No silver bullet for wastewater challenges

There is no silver bullet for tackling all of the challenges the owners of each wastewater management system face. They are as complex and challenging as the network itself. Multiple, innovative solutions will need to be developed and adopted to deliver a sustainable future.

We will need new infrastructure, but that is only part of the solution. The Thames Tideway Tunnel is a 25km super sewer being built through the heart of London to capture the millions of tonnes of sewage that currently enter the River Thames each year, and instead divert it to a wastewater treatment centre in Beckton. It will cost Thames Water £4.9bn by the time it comes on stream, and will have taken eight years to construct.

Understanding, collaboration, and co-creation

This is where greater understanding about the water sector has a role. In many aspects of our lives, we are becoming more conscious about our consumption, our place in complex value chains and the influence we can exert on them. Rather than being out of sight and out of mind, the water sector should be driving awareness of the wastewater management system so that every person understands the part they play in maintaining it.

There are two parts to that need for understanding. The first is for customers to understand their role in what goes down the drain, or more precisely, what should not go down the drain. Fats, oils, greases, wet wipes, plastic-based sanitary items and nappies add unnecessary burden to our wastewater assets and harm to our waterways. There is a growing degree of awareness about this, but as a society, we have not yet seen behaviour change on a large enough scale for it to stop being an issue.

The public are rightly concerned when problems in drains and sewers bring ‘out of sight – out of mind’ wastewater to the surface © shutterstock/pingphuket

The second is to develop greater understanding of the challenges facing the water sector. We must understand why climate change is impacting our relationship with water – not only the increased risk of drought in summer, but also the increased prevalence of severe storms and their consequences.

This way, people should have a more complete understanding of their influence on the wastewater management system, the motivation for new infrastructure, and the need to do things differently in order to adapt to the challenges.

Adaptation, iteration, and forward-thinking

Doing things differently is key – the water sector cannot rest on its laurels. Many of the problems the sector is seeking to overcome are challenges in need of new and innovative solutions. If we are to change the status quo we need to bring in new ideas, new technologies, and new thinking to ensure the sector is continuously improving. That is the motivation behind Ofwat’s £200m Innovation Fund.

Previous winners have included a project to improve how companies can benefit from long-term weather forecasting to help predict and mitigate against the impact of high rainfall. It has awarded a project to ensure new housing developments add no extra burden to water supplies and wastewater capacity in communities, and projects to help communities become ‘water smart’ through urban designs that can handle increased rainfall.

But innovation must address more than existing challenges. We need to anticipate future challenges and technologies too. Consider the impending adoption of electric cars. Few, I imagine, would argue against the transition from combustion engines to electric vehicles (EVs), but because of their batteries, EVs are significantly heavier. That means more wear and tear on tyres and increased particles of tyre rubber on the road – which will inevitably be washed down the drains.

The wastewater innovation opportunity

There is huge opportunity in solving these challenges. There are environmental benefits, of course, but the biggest benefit is for customers. They want to know that their utility providers are environmentally responsible, and they benefit directly from cleaner air and pollution-free waterways. If we are innovating to tackle problems before they arise rather than cleaning up failures, this will help to drive down costs too.

In all of the areas outlined, innovation can play a role. Innovation in education and public awareness can influence consumption habits and behaviour change. Innovation that protects existing infrastructure and leads to advances in future infrastructure will help the industry drive up environmental standards.

For the benefit of everyone, the water sector needs greater innovation in the way we use and share data, and in how we detect where things have gone wrong. We need innovative approaches to the way we design our urban environments and manage our agricultural assets. We need to change the way we consume energy – and adopt innovations that help the sector achieve net zero, and even turn our wastewater resources into energy sources.

But it cannot – and should not – all come from within the water sector. Water is not the only sector facing issues around changing capacity, climate, technology, consumption, and public attitudes. We are not the only industry driving forward innovative solutions for consumers and the environment. The water sector needs to be inviting fresh thinking from other sectors with the boldest ideas that can deliver positive disruption – and support them to translate their solutions for the complexity of our water system. The Water Discovery Challenge is part of this drive to welcome new innovators and problem solvers into the water sector.

We are calling on innovators from outside of the water sector to apply their ingenuity to the big challenges we face. The challenge is a £4m open competition from Ofwat’s Innovation Fund. It is incentivising ideas from, and led by, those outside of the water sector. The goal is to open the sector to new groundbreaking insights and thinking that benefit consumers and the environment.


We are, quite rightly, challenged by campaigners, community groups and the media about sewage spills into waterways – an issue easy to understand but one with no obvious solution. The idea of replacing all sewers with bigger ones would require almost every road in the UK to be dug up.

Even if as a society we could accept the huge cost, massive disruption and carbon impact of this, there simply aren’t enough contractors in the UK to deliver this in a reasonable timescale. The water industry needs to tackle the harm that these spills cause – but this is only one of the challenges that the water sector faces. It must address challenges on all fronts for it to call itself truly sustainable.

Everyone in the UK has a role and influence on the sustainable future of wastewater management. It matters what consumers flush away, it matters what gets washed down the drain, it matters what we do as a regulator to incentivise (whether by carrot or by stick) industry change, and it matters what water companies do to implement innovative solutions. Where Ofwat, as a regulator, can help drive that wholesale change, we will.

Ensuring a sustainable future for wastewater is too important an issue to do alone. It requires a concerted effort to encourage and reward new ideas, new thinking and new expertise, whether from within the water sector or from bold innovators who have never worked with us before.

We need to be persistent and dogged in meeting the challenge the wastewater management watersector faces, so that we can continue to benefit from a reliable service without compromising the natural environment.

The Water Discovery Challenge is open to entries until 5 April 2023. Ofwat is looking for bold and innovative entrants from outside the water sector. It has identified five sectors where it believes there is particularly high potential for innovative crossovers: energy, cities and transport, construction, agriculture and farming, and digital, data and Internet of Things. To find out more about the competition and enter, visit

Marc Hannis
Ofwat Innovation Fund

Please note, this article will also appear in the thirteenth edition of our quarterly publication.

Subscribe to our newsletter


Please enter your comment!
Please enter your name here

Featured Topics

Partner News


Latest eBooks

Latest Partners

Similar Articles

More from Innovation News Network