METzero - Bringing the water sector towards Net-Zero using Microbial Electrochemical Technologies (METs)

Lead Research Organisation: Newcastle University
Department Name: Sch of Engineering


When water is wasted at the tap, we consider the water waste, but rarely the waste of energy gone into making this water potable, and almost never the wasted energy to treat the resulting 'waste' water. Yeti the UK the water industry accounts for around 3% of energy expenditure, and is estimated to be the fourth largest energy user. In the wastewater sector this is particularly incongruous: wastewater actually contains around 10 times more energy than is currently used to treat it.

Wastewater treatment technologies have changes little in the last 100 years. Much of the infrastructure was built for much lower population levels, and 'treatment' was focused on the simply removing organic content down to a level acceptable to discharge into waterways. There has been a slight shift in recent years toward recovery of resource specifically with the implementation of anaerobic digestion of sewage sludge to recover energy, however this is a small bolt on solution which can only recover around 10% of the energy spent. No technologies exist at scale capable of intelligently, controllably and flexibly recovering a variety of resources, closing the loop on the circular economy of human water cycle. If discharge standards are to be guaranteed in the future where energy costs are likely to be higher and weather effects more problematic then new smarter biotechnologies will be needed. Furthermore there will be a need to remove and ideally recover a wide range of other pollutants from ammonia through to microplastics or trace metals. New technologies are needed for the water industry to become the responsible, responsive service needed to meet the Netzero pledges for 2030, and the environmental needs of the coming decades.

Microbial electrochemical technologies are one such technology, which could help enable some of these changes, and lead to greater understanding of the biological processes involved in order to help develop further technologies. They are an anaerobic technology that works, like a battery, using waste organics as a fuel liberating electrons and protons. These electrons and protons can be the driving force for recovery processes either of energy directly through electrical current or indirectly through hydrogen gas, or useful chemicals such as caustic soda or ammonia. This research aims to robustly test and develop these technologies using large scale replicated reactors under realistic conditions. Within the lifetime of the grant we aim to develop a reactor capable of meeting the treatment needs of industry, thus having short term impact. We then aim to increase the value of this technology optimising and trialling the recovery of different resources. Furthermore, by conducting rigorous experiments, at large scale, and fully analysing the biological behaviour in these open systems and in particular during the start-up phase, we aim to establish a deep understanding of microbial community formation processes which will be applicable to other biotechnologies.


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