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.

Modern waste management is geared towards recycling and re-use. Inevitably, however, there will be some wastes that, having come to the end of their useful life, will require disposal to landfill. Many landfilled wastes are now treated prior to disposal, but the treatment does not necessarily remove all contaminants. In fact some pollutants can be concentrated into the final waste stream.Landfill sites are designed and operated to prevent contaminants contained in the wastes from polluting the surrounding environment (for example, water and air). However, the consequence of keeping the contaminants in the site is that the polluting potential of the site does not reduce and will last for a period measured in centuries rather than decades. This also means that the site will require looking after for a very long period (possibly hundreds of years), and it far from clear that the means to pay for this aftercare will last for that long into the future.The purpose of this research is to help develop techniques (simulations tools) that could be used to shorten the length of time that landfill sites pose a pollution risk. The research will be applicable to cleaning up the backlog of old landfill sites that exist across the UK. The research will also be of use in predicting the potential impact that new types of waste may have in landfills, in advance of any wholesale adoption of the technologies that produce them. This will make a positive and essential contribution to waste management policy and strategic decision making in the UK.The main way in which the pollution load of a landfill reduces is by the passage of water through the waste, accelerating breakdown mechanisms and flushing out contaminants. The introduction of air into landfills to encourage in situ 'composting' is also beneficial. It is important to understand the factors that control the movement of both water and air through landfills, and consequently there is a need to understand the relevant bulk properties of the wastes in landfills. We will develop a classification system that describes the essential characteristics of wastes, and undertake experimental work to quantify the bulk properties of wastes and link them to the description. From this it should be possible to improve predictions about how different waste types will behave in landfills. We will undertake tracer tests in both the laboratory and the field to develop an understanding of the bulk flow properties of wastes. However, very few tracers have previously been used successfully in wastes. Thus an early task will be to identify a range of tracers suitable for use in wastes, primarily by means of carefully controlled laboratory tests. Suitable tracers that we identify will be used in subsequent laboratory and field scale experiments. These experiments will be designed to investigate the process of contaminant flushing at a variety of scales. The results will be used to help develop a theoretical basis (modelling) that describes how efficiently contaminants will be removed from landfills in different situations. These models will be used to develop landfill management strategies by which the timescale of pollution can be reduced from centuries to decades or shorter.It is generally accepted that landfill gas generated within landfills as a result of ongoing degradation affects water movement and that water blocks gas flow. We will undertake laboratory experiments to provide visual evidence of the nature of the interference that gas and water have on each other. We will also develop models to explain and describe what we observe to help improve our understanding of the process.

Waste management is changing rapidly as the need to manage the earth's resources responsibly becomes increasingly accepted and enshrined in new legislation. Ideally, changes to the law, regulation and practice would be science-led; but in such a dynamic environment, scientific understanding and engineering know-how sometimes struggle to provide support with the result that the potential consequences of legislative and financial drivers for change may not be fully thought-through. For example, the EU Landfill Directive was enacted mainly to reduce fugitive greenhouse gas emissions from landfills, but its implementation with current treatment options could have the opposite effect. The aim of the Platform Grant is to provide the University of Southampton Waste Management Research Group with the stability and flexibility needed to explore new directions for its research that will provide the waste industry with the science and engineering needed for sustainable response to financial, regulatory and social drivers, and will address the legacy of unsolved problems arising from previous waste management practices. Key areas for development are:1) Field scale implementation of current research - enabling a rapid response when suitable study sites arise: We have developed the science needed by industry to reduce the long term pollution liability of landfills by a variety of remediation techniques, including flushing and in situ aerobic treatment. While excellent progress has been made, major uncertainties remain in upscaling from the laboratory to the field. This will be addressed in future research, in which we plan to investigate flushing and aeration at the field scale by running trials within discrete, bounded areas of MSW landfill(s) with the aim of significantly reducing the long term polluting potential of the wastes. 2) Resource recovery - second generation bio-based products and energy carriers from organic wastes and post-landfill processing: Government policy and strategic waste planning has highlighted a vital role for energy and commodity grade resource recovery in UK waste management practice. The infrastructure to facilitate this is already taking shape, through source segregated collection systems, growing markets for recovered products and pricing structures (e.g. ROC and feed-in tariffs) to encourage renewable energy production. The technology, however, is still in its infancy and underpinning research is urgently needed to support process engineering design, adapt existing technologies and exploit the potential for using waste as a raw material for biorefineries and solid recovered fuels. This will be done within an overall energy, materials and product recovery framework to include MSW processing operations where source segregation is not practised and also post-land filled wastes to reduce their long-term pollution potential and to create additional void space. 3) Application of recent and ongoing research to new forms of wastes - identifying key synergies: There is immense potential for translating the results of our current research into new areas, in particular in characterisation and near field contaminant transport modelling of low and very low level radioactive wastes.4) Development/promotion of a Sustainable Waste/Resource Management Forum including decision support systems (DSS - establishing expertise and stakeholder engagement, and maximising impact: DSS will make the results of the Group's research more readily available to users, encouraging knowledge transfer and maximising impact. Little work has been done to develop DSS for the waste industry, although the potential benefits have been recognised by some. DSS will also facilitate policy and operational decisions on the complex technology and process options available

This project seeks to investigate the potential for using waste materials within combustion systems within the UK in the future, and how the combustion of such wastes might affect the ability of a power station to respond to changes in electricity demand. The purpose is not to look at today's electricity system and systems of governance with respect to combustion of wastes, but to consider how a rational system would be designed that utilised all potential fuel streams (and takes into account that different wastes will contain different levels of trace elements, some of which may be quite minor). An important point is that many wastes are currently landfilled - meaning that both the energy content of the waste is lost and a bulky material ends up in landfill. Here, we will conduct experiments looking at emissions of trace elements during combustion and co-firing (with coal) of different types of "waste" materials (for example, wood from demolition sites), together with analysis of ashes produced. The results will then be used to generate models of power plants burning wastes, and used to determine whether, for the wastes examined, the most rational use of the waste is combustion in dedicated facilities or co-combustion. It is clear that some of the wastes we will examine currently fall within the remit of the waste incineration directive (though all will be non-halogenated). We will examine whether this is scientifically valid.

Complex microbial communities underlie natural processes such as global chemical cycles and digestion in higher animals, and are routinely exploited for industrial scale synthesis, waste treatment and fermentation. Our basic understanding of the structures, stabilities and functions of such communities is limited, leading to the declaration of their study as the next frontier in microbial ecology, microbiology, and synthetic biology. Focusing on biomethane producing microbial communities (BMCs), we will undertake a two-tiered approach of optimising natural communities and designing synthetic communities with a focus on achieving robust, high-yield biomethane production. Within this biotechnological framework, our proposal will address several fundamental scientific questions on the link between the structure and function of microbial communities. To ensure success in this challenging project, we assembled the strongest possible interdisciplinary research team that combines significant practical and scientific expertise in microbial ecology and evolution, systems modelling, molecular microbiology, bioengineering, genomics, and synthetic biology. We are confident that this team will deliver and that this project will result in significant impact in the scientific and industrial domains. Through our work, described in detail below, we will; significantly improve the current understanding of the structure-function relation in microbial communities, provide the scientific community with a systematic, temporal genomics and transcriptomics dataset on complex microbial communities, develop novel computational tools for microbial community (re)design, and experimentally build synthetic BMCs that will act as model ecosystems in different research fields. These scientific developments, in turn, will accumulate in the development of more sustainable bioenergy solutions for the UK economy by optimising the communities underlying biomethane production. This will help to drive the efficiency of biomethane as an alternative fuel source.