By Giulia Pizzagalli, Innovation Project Manager for Triple Carbon Reduction at Anglian Water

This summer will mark the beginning of Anglian Water’s pilot trial for its Triple Carbon Reduction (TCR) project, a novel approach to treating wastewater that will help achieve the objectives set by the Water UK Net Zero 2030 routemap.

Led by Anglian Water, supported by partners from industry and academia, and funded through the Ofwat Innovation Fund, the TCR project has the potential – and main goal – to provide a viable and sustainable solution for carbon emissions reduction in wastewater treatment. To do this, the initiative is seeking to generate green hydrogen from electrolysis in one of Anglian Water’s wastewater treatment facilities and couple an electrolyser with a biological treatment process, called MABR (Membrane Aerated Biofilm Reactor).

Why The Need To Reduce Carbon Emissions In Wastewater Treatment?

The water sector has been actively calculating its greenhouse gas (GHG) emissions for over a decade and has achieved notable reductions, as reported by Water UK’s Net Zero Routemap 2030. Despite these efforts, the sector is still responsible for nearly a third of the UK’s industrial and waste process emissions. Looking ahead to 2050, the industry anticipates an increase in its share of national emissions due to the challenges associated with decarbonisation processes. With this in mind, we intend to prevent this scenario and contribute to reaching new milestones in carbon emissions reduction while building a successful case for an operational solution that reduces emissions through on-site generation of green hydrogen.

Where Is The Innovation?

The coupling of electrolysis and MABR represents a paradigm shift in wastewater treatment, an elegant solution to reduce carbon and recover resources. Electrolysis, utilising renewable energy and water, is employed to generate hydrogen and oxygen gas. The latter, traditionally considered a byproduct, finds a novel purpose within the Triple Carbon Reduction project. In conventional wastewater treatment plants, a significant portion of energy is consumed in aeration processes to provide oxygen necessary for microbial degradation of organic matter. However, by harnessing the oxygen produced through electrolysis, the Triple Carbon Reduction project aims to demonstrate that the energy-intensive aeration step can be significantly optimized, leading to a substantial reduction in energy consumption and process emissions from treatment, in particular nitrous oxide.

A Triple Approach

The project aims to achieve three main carbon benefits, which come together to represent a triple carbon reduction:

Green hydrogen production:

The Triple Carbon Reduction project not only addresses environmental challenges but also unlocks new opportunities in renewable energy generation. Electrolysis, as a means of hydrogen production, holds immense potential for clean energy applications; generating an additional scurce of renewable energy and representing an alternative to fossil fuels in a variety of internal applications, from fuel cells to hydrogen storage systems, this solution will offer a pathway to decarbonisation and energy independence for wastewater treatment facilities and surrounding communities alike.

Through a partnership with a hydrogen off-taker, we plan to explore hydrogen demand first to the automotive market, including buses and hydrogen demonstration vehicles, such as trucks, refuse collection vehicles and vans. We anticipate that the hydrogen produced will have the potential to fuel approximately 30 hydrogen vehicles, with the prospect of exploring markets and demand for hydrogen both internal and external.

Reducing energy consumption:

Treating wastewater is a very energy-intensive process. In countries like the UK, approximately 3 percent o total energy is allocated to this task, with wastewater aeration usually constituting over half of this usage.

In MABR (OxyFILM), developed by our partner OxyMem, the biomass uses oxygen to support its metabolism, degrading carbon and nitrogen-based pollutants. Unlike other biological processes, the oxygen is supplied through a bubble-less technology and directly to the biofilm via diffusion through the membrane. We estimate that this approach to the treatment of wastewater will consume up to 85% less energy than other conventional processes in place, offering a significant jump forward in our journey towards achieving Net Zero.

Eliminate greenhouse gases:

We know nitrous oxide (N2O) has a Global Warming Potential almost 300 times higher than carbon dioxide; this is yet another compelling reason for relying on the innovative approach of Triple Carbon Reduction. Initial results from MABR trials elsewhere suggest that a bubble-less MABR solution could help address harmful N2O emissions in aerobic wastewater treatment. The project aims to exploit the synergy with the electrolyser, using the waste oxygen produced by electrolysis. Essentially, gradually releasing oxygen to the air delivered via the membrane could help stabilise and optimise the treatment process, and could lead to a reduction in nitrous oxide generation, which could be then captured and eliminated at a point source in the membrane off-gas.

The Pathway To Full Scale Adaptability

For this initiative, we partnered with many academic institutions, businesses, and water providers to ensure the successful completion of the project.

For instance, our partners at Cranfield University, alongside OxyMem™ and Jacobs, are helping us analyse data to optimise the balance between reducing nitrous oxide emissions and minimising energy usage while ensuring effective wastewater treatment . Cranfield will also help us understand cost-effective and sustainable pre-treatment options for treated wastewater, to promote its use as electrolyser water feed.

Imperial College London, are conducting a comprehensive life cycle assessment to evaluate resource recovery and hydrogen implementation pathways, to inform future plant designs. The University of East Anglia is engaging with customers and the local community to gauge sentiments regarding the installation of hydrogen production facilities at wastewater treatment plants, shaping future customer engagement approaches to sustainability matters. At the same time, our partners ERM are in charge of evaluating the entire system, identifying potential end users for the hydrogen produced at demonstration plants and assessing the feasibility of large-scale adoption.

We are optimistic that the insights gathered from the Triple Carbon Reduction first demonstration will help us redefine the landscape of wastewater treatment, minimising environmental impact and moving towards more sustainable and effective wastewater management. We are already witnessing firsthand the benefits of investing in innovation. As a business, we are currently on track to generate 45 percent of our energy production from renewable sources by 2025 and achieve our net zero goals by 2030.