Learnings

Outcomes

The project has generated new technical and operational evidence on the feasibility of producing green hydrogen directly from contaminated industrial wastewater using a NextGen membraneless electrolyser. Laboratory-scale testing demonstrated that hydrogen production from a range of representative industrial wastewater streams is technically achievable, and that simple pre-treatment steps such as skimming and electrolyte modification can improve operational stability and performance for certain water types. 
Through this work, the technology has progressed from an early proof-of-concept towards an integrated laboratory-validated system (TRL 2-3 to TRL 3-4), providing increased confidence in its applicability to real industrial environments. The project has also developed a flexible testing architecture and experimental framework that can be reused to assess additional wastewater types. 
The project outcomes identify clear opportunities for follow-on work to further develop and de-risk the technology. Future activities could include longer-term testing to assess electrode durability and degradation when operating on wastewater-derived electrolytes, optimisation of pre-treatment and electrolyte modification strategies for specific industrial wastewater profiles, and larger-scale validation to evaluate performance under more representative operating conditions. Further studies could explore how distributed hydrogen production at industrial customer sites could support future network planning and decarbonisation strategies across the WWU network. 
Together, these next steps would build on the learning generated in this project and help inform future investment, innovation and policy decisions related to low-carbon gas networks. 
In addition to the technical learning generated, the project has provided WWU with valuable insight into how alternative water sources could support future distributed hydrogen production across industrial regions connected to the gas network. The findings support wider industry ambitions around industrial decarbonisation, resilient low-carbon gas systems and reducing barriers to hydrogen deployment, particularly where access to purified water or significant water treatment infrastructure may otherwise limit viability. 
The project also contributes to the wider evidence base being developed across the hydrogen sector regarding decentralised hydrogen production and industrial cluster decarbonisation. The learning generated will help inform future innovation activity, network planning considerations and potential follow-on demonstration projects exploring how waste process water-derived hydrogen production could operate alongside future hydrogen injection, industrial energy systems and regional decarbonisation strategies. 
The project has strengthened collaboration between WWU, HydroStar and Cardiff University and established a foundation for potential future development activity, including larger-scale demonstrations, long-duration operational trials and further technoeconomic optimisation. Dissemination of the learning through innovation reporting, academic engagement and wider industry forums will help support broader understanding of the opportunities and challenges associated with wastewater-fed hydrogen production. 

Lessons Learnt

The project has successfully demonstrated that wastewater-fed electrolysis is technically feasible and has generated encouraging results across a range of representative industrial wastewater streams. Several areas have also been identified for further development before progression to higher TRL demonstration activities, although no significant technical barriers were identified during the project. 
One of the key lessons learnt is the significant influence wastewater composition has on electrochemical behaviour and hydrogen production performance. Whilst the project demonstrated that a wide range of wastewater streams can support hydrogen production, different water chemistries responded differently to skimming, electrolyte modification and particle addition. Future projects should therefore focus on developing more tailored treatment and electrolyte optimisation approaches for specific industrial wastewater profiles. 
The project also highlighted the importance of long-duration operational testing. Whilst the short-term electrochemical and hydrogen production results were encouraging, longer-term testing will be required to better understand electrode degradation, fouling behaviour, contaminant build-up and maintenance requirements when operating continuously on wastewater-derived electrolytes. This will be important in understanding operational lifetimes, maintenance intervals and overall commercial viability at scale. 
Initial future testing could continue at a similar laboratory scale, however progression towards larger demonstration systems, potentially at 10kW scale and above, will be important in understanding how the technology performs under more representative commercial operating conditions. 
Another important learning outcome was the value of integrating physical  process water treatment with hydrogen production within a single system architecture. The work demonstrated that contaminant removal and hydrogen generation can be complementary processes, creating opportunities for industrial users to reduce both wastewater management costs and carbon emissions simultaneously. 
From a WWU perspective, the project has improved understanding of how decentralised hydrogen production could potentially be integrated around industrial clusters and high-demand customers in the future. The findings support the view that alternative water sources may help improve the flexibility, resilience and geographic scalability of hydrogen production across the network, particularly in regions where access to purified water could otherwise become a barrier. 
Future work should now focus on:

• Larger-scale validation and longer-duration operational trials
• Further optimisation of waste process water pre-treatment and electrolyte systems
• Assessment of electrode degradation and maintenance requirements
• Technoeconomic optimisation of particle recovery and additive use
• Evaluation of how distributed wastewater-fed hydrogen production could support future network planning and industrial decarbonisation strategies

Overall, the project has provided a strong early-stage evidence base and generated encouraging technical and operational results, supporting further development and follow-on innovation activity, particularly around longer-term testing, scale-up and optimisation for different industrial wastewater streams.