We are faced with meeting the agricultural demands of a growing population estimated to reach 9.8 billion people by 2050 on soils depleted of essential nutrients, with declining yields and a projected reduction in future rainfall in key agricultural regions. A circular economy between agriculture and organic waste streams can recycle essential resources for farming through the recovery of water, biomass, and nutrients from sanitation waste solids, effluents, and livestock manure at scale. This offers benefits to agroecological practices in farming by reducing the reliance on chemical fertiliser inputs with multiple benefits that improve soil health, reduce greenhouse gas emissions from farming, and reduce water pollution in drainage from fields. However, there are potential risks and challenges associated with this solution and these need to be fully understood to enable resource recovery to operate in a safe and sustainable manner in the long term. Firstly, the gastrointestinal tracts of humans and animals are a source of pathogens to the environment and agriculture food chain. So, reusing these wastes could potentially spread these pathogens to the food crops we consume. Secondly, manure and sewage are sources of veterinary and medical chemicals to the environment; these compounds can enhance a microbe's ability to resist treatment drugs, such as antibiotics. This ability to resist treatment drugs can spread to other microbes important for plant, animal, and human diseases. Antimicrobial resistance (AMR) is a global public health crisis that is predicted to cause 10 million deaths per year by 2050. Currently, livestock and the environment are recognised as reservoirs of antimicrobial resistant microbes and implicated in the dissemination of these AMR microbes. Science-based methods to assess the environmental, livestock and human health risks of combined exposure to antimicrobial selective compounds and AMR microbes are therefore central to fully realising the potential benefits of a sanitation-agriculture circular economy. Models, analytical tools, and quantitative assessment methods to understand, measure and assess the impacts of agricultural exposure routes urgently warrant scientific attention. Through understanding the safety risks recycling waste streams pose, new interventions can be devised to minimise these risks, making resource recycling a viable mechanism to increase soil and farm productivity. Working with water utility companies and the National Pig Centre, we will investigate how water and farm waste can be recycled to be used in agriculture. Using laboratory models, we will identify where pathogens and chemicals aggregate along the different waste streams, thus identify where interventions need to be made. Using this information, we will define a risk assessment analysis to tackle pathogen and chemical buildup. We propose to build on the 'one-health, one environment' approach to AMR by acknowledging the connectivity between humans, animals and the environment. This project will support the development of a UK sanitation-circular economy and build a UK-led innovation network with global reach. The overall aim of the project is to build a community of educational, industry, farming, and government colleagues to increase the capacity of the UK to address global pollution challenges associated with adopting a circular economy to support agricultural production. A circular economy approach is essential in meeting global agricultural needs, especially enhancing the role that farming can play in climate control and our need to move towards Net Zero greenhouse gas emissions. This proposal will pave the way in achieving this goal whilst minimising the impact of utilising waste materials on the environment and animal and human health.

The current fuel production and related industries are still heavily reliant on fossil fuels. BP's "Statistical Review of World Energy" published in 2014 states that the world has in reserves 892 billion tonnes of coal, 186 trillion cubic meters of natural gas, and 1688 billion barrels of crude oil. Although these represent huge reserves, taking into account today's level of extraction, would mean that coal would be exhausted in 113 years and natural gas and crude oil would be extracted by 2069 and 2067, respectively. In the meanwhile, the CO2 atmospheric concentration has increased from 270 ppm before the industrial revolution to 400 ppm today and its annual release is predicted to exceed 40GT/year by 2030. As the world population increases, breakthrough technologies tackling both fuel supply and carbon emission challenges are needed. The use of CO2 from, or captured in industrial processes, as a direct feedstock for chemical fuel production, are crucial for reducing green house gas emission and for sustainable fuel production with the existing resources. The aim of this project is to develop a breakthrough technology with integrated low cost bio-electrochemical processes to convert CO2 into liquid fuels for transportations, energy storage, heating and other applications. CO2 is firstly electrochemically reduced to formate with the electric energy from biomass and various wastes and other renewable sources by Bioelectrochemical systems (BES). The product then goes through a biotransformation SimCell reactor with microorganisms (Ralstonia) specialised in converting formate to medium chain alkanes using a Synthetic biology approach. The proposed technology will develop around the existing wastewater treatment facilities from for example, petroleum refineries and water industries, utilising the carbon source in wastewater, thus minimising the requirement to transport materials and use additional land. To tackle the grand challenges, a multidisciplinary team of five universities will work together to develop this groundbreaking technology. Our research targets two specific aspects on renewable low carbon fuel generation: 1) Use of biomass and wastewater as a source of energy and reducing power to synthesise chemicals from CO2. 2) Interface electrochemical and biological processes to achieve chemical energy-to-fuels transformation. To achieve the goal of this project, there are three major research challenges we need to tackle: 1. How to maximise the power output and energy from wastewater with Bioelectrochemical systems? 2. How to achieve CO2 conversion to medium chain alkanes through reduction to formate in Microbial electrolysis cells, and then SimCells? 3. Can we develop a viable, integrated, efficient and economic system combining bio-electrochemical and biological processes for sustainable liquid fuel production? To tackle these challenges, we need to maximise energy output from wastewater by using novel 3-D materials, to apply highly active electrochemical catalysts for CO2 reduction, to improve efficiency of SimCell reactor, and to integrate both processes and design a new system to convert CO2 to medium chain alkanes with high efficiency. In this study, rigorous LCA will be carried out to identify the optimum pathways for liquid biofuel production. We will also look at the policies on low carbon fuel production and explore the ways to influence low carbon fuel policies. Through the development of this innovative technology, we will bring positive impact on the UK's target for reducing CO2 emissions and increasing the use of renewable energy.

Ageing infrastructure is an increasing economic and environmental problem. Economic because, while the production cost of one cubic metre of concrete varies between £45 - £55, it is estimated that currently the direct cost for repairing/maintaining one cubic metre of the same material is around £100. Environmental because production of cement generates 5 to 8% of the world's carbon dioxide emissions. Counteracting the degradation of concrete would lower the requirement for new materials and thus reduce the consumption of resources and the emission of greenhouse gases. Engineers have proposed a revolutionary solution, which was inspired by nature: self-healing materials able to self-repair as a result of the metabolic activity of bacteria. The main mechanism of concrete healing is the microbial-induced precipitation of calcium carbonate (MICP), which fills the cracks of the damaged material. However, the current approach in microbial self-healing concrete technology is to identify a few species of bacteria that work for limited sets of concretes and environments, and to optimise their MICP performance incrementally by experiments. This leads to solutions that are poorly transferable to new applications, unless new costly experimental campaigns are undertaken. In this proposal we aim to provide a new theoretical basis to predict the most promising combinations of bacteria and concrete, once the application-specific chemical compositions of the concrete of the surrounding environment are identified. This will establish a new paradigm for the digital design of concrete-bacteria systems and will enable technology transfer across the constructions sector. The approach we propose entails two main steps: 1) developing and validating the world-first simulator of bacterial self-healing in concrete, starting from the length-scale of a single crack (1-100 micrometres) and then transferring information on the kinetics of self-healing to macroscale simulations of concrete mechanics; 2) using the new simulator to inform an experimental campaign aimed at optimising the formulation of self-healing concrete for application in the aggressive chemical environment of an industrial wastewater treatment. The new simulator will be obtained by building on three existing state-of-the-art simulators that have been very recently developed at Newcastle and Cardiff universities and that model, to date separately, the three main steps involved in self-healing: i) bacterial growth; ii) kinetic evolution of an aggregate of mineral particles immersed in a solution; and iii) macro-mechanics of concrete elements with evolving strength and stiffness. The experiments will first provide inputs to the simulations and data for their validation. These experiments will be carried out in university laboratories and will address all the relevant length scales, from the nanoscale of the morphology of the mineral phases in concrete, to the microscale of the self-healing process inside single cracks, to the macroscale of self-healing concrete samples. The validated simulations will be run predictively to simulate the environmental conditions inside a wastewater treatment plant. The simulations will identify the best combinations of bacteria and concrete chemistry to ensure self-healing in such conditions, and the final experiments will produce the simulation-guided self-healing concrete and test their performance in the facilities of our industrial partner Northumbrian Water. If successful, this project will provide a completely new way to approach the design of self-healing materials via simulations. This would drastically reduce the cost, time, and uncertainty related to developing these materials, enhancing the rate of progress in the field by orders of magnitude and putting the UK at the forefront worldwide in this new technology.

The world's population stands at 7.5 billion and the UN predicts this could rise to 11 billion by 2100 with increasing urbanisation [13]. The production of human wastes and wastewaters in an unavoidable consequence of life. Treating this so it can be safely released to the environment is of paramount importance to both human health and the ecosystems we depend on. Effective technologies exist which are able to treat the large volumes of wastewater produced in urban areas, but these have changed little in the last 100 years. Activated sludge is the most prevalent method used (by volume treated) but it is energy intensive, accounting for as much as 3% of electricity consumption in developed economies [15]. Furthermore 80% of the world's wastewater goes into receiving waters untreated [16]. This technology is expensive and unsustainable for some, but for large parts of the world is simple unaffordable. A large proportion (roughly 50%) of the energetic costs in the activated sludge process comes from the need to bubble oxygen through the large tanks of sewage, such that the aerobic bacteria within these wastes can use the oxygen to digest the organic matter to carbon dioxide within the waste, making it safe to release to the environment. However there is energy contained within these organics in the wastewater. In activated sludge all this energy goes to the microorganisms, and we as engineers are unable to access it. Thus although effective, the activated sludge process uses substantial amounts of energy to get rid of the energy within the wastewater. If we are to move to a more sustainable form of wastewater treatment, the aerobic activated sludge process need to be replaced by an anaerobic technology. Anaerobic technologies also use naturally occurring bacteria to digest waste, but here as oxygen is not present the bacteria must produce a different waste, methane in the case of classical anaerobic digestion, or electrons in the case of Bioelectrochemical digestion. In this scenario the bacteria take only some of the energy contained in the wastewater, and we as engineers can take the rest. Anaerobic digestion has also been around for 100 years and is used on many farm and industrial waste streams as well as on the sludge produced by wastewater treatment sites. However it is not effective at treating wastewaters which are dilute, and is not effective at the lower temperatures which are typical of the UK and other countries. Bioelectrochemical systems (BES) are a newly developing technology that use specialised bacteria to grow on an electrode and produce currents as they digest the wastes, essentially acting like a biological battery. BES technologies have been shown to work with dilute wastewaters and at low temperatures, however they are not energetically efficient, with up to 90% of the total input energy going missing. Some of this energy will go to the bacteria as they metabolise, but some will be lost as heat. I hypothesise that when these bacteria live together attached to a surface in a biofilm, such as on an electrode, the heat generated is creating a localised warm environment allowing bacteria to survive and metabolise at low wastewater temperatures. Currently we do not know how much energy is going to heat, and nor do we have the ability to accurately quantify it. The aim of this grant is to develop a platform to make these critical measurements in order that we will then be able to engineer and husband the heat energy to transform wastewater treatment.

Climate change is causing, and will continue to cause, more intense precipitation events and greater amplitude of warm and cold temperatures leading to severe flooding, extreme drying, freezing and thawing. This will affect many parts of the urban geo-infrastructure such as shallow foundations, retaining structures, buried utilities, road subbase and railway formations. The costs of damage due to shrink/swell movements on clay soils have resulted in economic losses of over £1.6 billion in the UK during drought years. The novelty of the proposed research is the development of "climate adaptation composite barrier systems" (comprising water holding layers and a capillary barrier) capable of limiting the impact of a changing environment on the geo-infrastructure and hence increasing their engineering sustainability and resilience. Environmental cyclic actions imposed on our infrastructure are governed by soil-plant-atmosphere interaction, which is a coupled thermo-hydro-mechanical problem driven by the atmosphere and influenced by soil type, stress history, stress level, mineralogy, soil-water chemistry and vegetation. Understanding this complex problem requires systematic research and a coherent approach. This proposal describes systematic experimental and numerical modelling studies to understand the response of composite barrier systems, when subjected to extreme weather events and long-term climate changes, and to develop appropriate sustainable adaptation technologies to mitigate potential impacts on urban geo-infrastructure.