Used water innovations to tackle the climate crisis

In the leadup to announcing the winners of the Catalyst stream of our second Water Breakthrough

Challenge (‘Breakthrough 2’), we’re shining a spotlight on the winners of our first Water Breakthrough Challenge with a series of interviews and case studies – this week, meet three teams working to cut climate change-causing gases and meet the sector’s ambitious climate commitments. Missed last week’s? Catch up on the game-changing, data-driven initiatives here. 

Last week, the Intergovernmental Panel on Climate Change (IPCC) published their latest report, outlining the ways climate change is already impacting people around the world, and establishing and reestablishing an urgent need for governments and industry to take action.

The UK’s water sector is tackling this challenge head on, with a world-first, sector-wide commitment to reach net-zero climate change-causing gases by 2030 and, as acknowledged in Ofwat’s Net zero principles position paper, have already reduced gross operational emissions by almost 45% between 2011 and 2019.

Through the Fund, we aim to turbocharge these efforts to cut climate change-causing gases by supporting water companies to work together in new and different ways to address the shared challenges they face. Our first competition, the Innovation in Water Challenge, has already funded a number of highly collaborative initiatives to help address climate change, and this momentum has continued into our Water Breakthrough Challenge 1 competition.

Read on for interviews with three winners helping the sector reduce climate change-causing gases, and combat the climate crisis.

At the recent COP26 United Nations climate conference in Glasgow, reducing climate change-causing gases from water and used water treatment processes was identified as a key priority for the water sector. This project, led Anglian Water in partnership with multiple water companies, universities and industrial partners, aims to deliver three significant reductions by using an innovative membrane technology known as a ‘Membrane Aerated Biofilm Reactor’ to clean used water.

It’s called ‘Triple carbon reduction’ as it cuts climate change-causing gases in three ways: (1) This technology uses less power than traditional systems; (2) it reducing the amount of nitrous oxide (a greenhouse gas more than 300 times more powerful than carbon dioxide) released into the atmosphere; and (3) produces a new, low-carbon source of hydrogen which can be used to generate, store and transport renewable energy at scale.

Phosphorus, if unchecked, can be very damaging to water environments, promoting excessive algal growth and depriving fish and other aquatic animals of oxygen. Typically, water companies rely on metal-based coagulants (chemicals which cause particles in water to ‘clump’ together) to remove this phosphorous from the wastewater they treat, but the production and transport of these chemicals generate a large amount of climate change-causing gases. With the consumption of these chemicals predicted to increase significantly by 2025, an alternative approach has the potential to yield considerable benefits for the climate.

Through this project, United Utilities and its partners will explore chemical free options for phosphorous removal which can reduce the carbon footprint of used water treatment, without negatively impacting water quality. These options range from electrocoagulation (using electrical reactions to clump together particles), to natural or plant-based coagulants, and will be trialled at rural wastewater which face unique challenges for chemical-free treatment. If these options work, they could be used at any used water treatment plant in the UK, or around the world.

Often, 30-40% of a water company’s climate change-causing gases are generated from treating and managing used water. That is why eight water companies, led by Thames Water, are collaborating with academia to generate ‘anaerobic’ treatment processes (a process without oxygen) which do not release nitrous oxide, a powerful climate change-causing gas. These processes have the potential to drastically reduce energy use (by more than 80%), and almost eliminate climate change-causing gases. In addition to the extensive reductions in climate change-causing gases, this innovative process will also deliver big cost savings which can be passed on to customers. The anaerobic process will generate biogas (gas from biological processes) which can be used to generate energy to help power the  treatment works reducing the demand on the national grid. The process will also reduce the amount of sludge (the solids left over from treating used water) by 96%, significantly reducing costs of transporting and managing this waste.

Through this project, Thames Water and their partnerswill be testing the new anaerobic process with a mobile pilot plant. This will allow them to check how the approach can be used in a variety of situations, laying the groundwork for this solution to be adopted nationally.