The world is changing fast. Rapid urbanisation, large scale population movements, increasing pressure from climate change, natural and man-made disasters create enormous pressures on local and national governments to provide housing, water, sanitation, solid waste (rubbish) management and other critical services. In the UK there is also an ongoing challenge associated with aging infrastructure (many sewers for example are more than 100 years old) and at the same time, calls for new investment in housing, the construction of new towns, and an urgent need to reduce reliance on expensive fossil fuels, reduce pollution and increase the recovery of valuable resources. As economic conditions improve, people naturally demand better services; twenty-four hour water piped direct to the house and convenient safe private toilets have replaced public stand pipes and public toilets as the aspiration of many families in Africa, Asia, the Pacific and Latin America (the "global south"). All of this creates both a challenge and an opportunity. In coming decades there will be a huge demand for new infrastructure investments in the global south; more than 4.4 billion people worldwide do not have a sanitation system that effectively collects and treats all the waste produced by families, while 2.4 billion people urgently need new water supply services. The UK engineering industry is poised to play a significant role in meeting both this global demand and the need for new innovations at home. But therein lies the challenge; the new generation of services and infrastructure must, by very definition, be essentially different in nature from what has been traditionally provided. In an era of increasing uncertainty from, for example, the changing climate, the traditional approach to the design of piped water supplies and sewerage networks would result in such a major over design that the investment costs alone would be prohibitive. Similarly, it is no longer acceptable to just keep adding additional treatment processes on to waste water treatment systems to meet increasingly challenging conditions and higher discharge standards, nor is it acceptable to continue to pump valuable nutrients and carbon into our rivers and streams; new approaches are needed, which recover the nutrient and energy value of human and solid waste streams, in fact turning away from the idea of waste altogether and moving towards the idea of resource management and the so-called circular economy. What is needed to meet this demand is a new generation of research engineers and scientists trained not only in the fundamentals of 'what is known' but in the more challenging area of 'what can be re-imagined'. The EPSRC Centre for Doctoral Training in Water and Waste Infrastructure Services Engineered for Resilience (Water-WISER) will train five cohorts of researchers with the new skills needed to meet these enormous challenges. Students in the Centre will have the opportunity to study at one of three globally-leading Universities working on resilient infrastructure and development. They will take a one year Masters course and then move on to carry out tailored research, in partnership with engineering consultancy firms, universities or development agencies such as the World Bank, UNICEF or WaterAid; studying how to deliver innovative, effective and resilient infrastructure and services in rapidly growing poor cities. Water-WISER graduates will combine a solid training in the fundamental engineering and science of water and sanitation, solid waste management, water resources and drainage, with much broader training and development which will build the skills needed to collaborate with non-engineers and non-scientists, to work with sociologists and political scientists, city planners, digital designers, business development specialists and administrators, health specialists, professionals working in international development and finance.

The majority of countries around the world maintain a disinfectant residual to control planktonic microbial contamination and/or regrowth within Drinking Water Distribution Systems (DWDS). Conversely, some European countries prohibit this practice because the residuals react to create disinfection by-products, which are regulated toxins with carcinogenic effects. Critically, the impact of disinfectant residuals on biofilms is unknown, including their role in creating a preferential environment for pathogens. Biofilms grow on all surfaces; they are a matrix of microbial cells embedded in extracellular polymeric substances. With biofilms massively dominating the organic content of DWDS, there is a need for a definitive investigation of the processes and impacts underlying DWDS disinfection and biofilm interactions such that all the risks and benefits of disinfection residual strategies can be understood and balanced. This balance is essential for the continued supply of safe drinking water, but with minimal use of energy and chemicals. The central provocative proposition is that disinfectant residuals promote a resistant biofilm that serves as a beneficial habitat for pathogens, allowing pathogens to proliferate and be sporadically mobilised into the water column where they then pose a risk to public health. This project will, for the first time, study and model the impact of disinfectant residual strategies on biofilms including pathogen sheltering, proliferation, and mobilisation to fill this important gap in DWDS knowledge. The potential sources of pathogens in our DWDS are increasing due to the ageing nature of this infrastructure, for example, via ingress at leaks during depressurisation events. Volumes of ingress and hence direct exposure risks are small but could seed pathogens into biofilm, with potential for proliferation and subsequent release. An integrated, iterative continuum of physical experiments and modelling is essential to deliver the ambition of the proposed research. We will make use of the latest developments in microbiology, internationally unique pilot scale experimental facilities, population biology and microbial risk assessment modelling to understand the interactions between the disinfection residuals, biofilms, pathogens and hydraulics of drinking water distribution systems. This research will combine globally renowned expertise in mathematical modelling, drinking water engineering, quantitative microbial risk assessment, and molecular microbial ecology to deliver this ambitious and transformative project. If the central proposition is proven, then current practice in the UK and the majority of the developed world could be increasing health risks through the use of disinfectant residuals. The evidence generated from this research will be central to comprehensive risk assessment. A likely outcome is that by testing the hypothesis, we will prove under what conditions the selective pressures on biofilms are unacceptable, and in so doing understand and enable optimisation of disinfection residuals types and concentrations for different treated water characteristics. Although focused on the impacts of disinfectant residuals and pathogens, the research will also generate wider knowledge of biofilm behaviour, interactions and impacts between biofilms and water quality within drinking water distribution systems in general and relevant to other domains. The impact of this research will be to deliver a step change in protecting public health whilst minimising chemical and energy use through well informed trade-offs between acute drinking water pathogen (currently unknown) and chronic disinfectant by-product (known and increasing) exposure. The ultimate beneficiaries will be the public, society and economy due to the intrinsic link between water quality and public health.

Our vision is that of a city where infrastructure is autonomously maintained and dynamically responsive, focused on: securing the health & wellbeing of its citizens; contributing to flourishing and sustainable natural systems in the city; and creating positive economic and societal outlooks. Towards our vision we will tackle the Grand Challenge of: Zero disruption from Streetworks in UK Cities by 2050. Our strongly interdisciplinary team aspires to fulfil our Grand Challenge through pioneering scientific research (and research methods) into: autonomous systems for minimally invasive infrastructure sensing, diagnosis and repair; development of advanced robots for deployment in complex live city environments; and the socio-technical intricacy of the robot - human - natural systems interfaces. We will develop pioneering robot designs, technical implementations and socio-economic impact cases linked to specific application requirements, starting with three case-study systems: o "Perch and Repair" remote maintenance and modernisation of lighting columns to promote their use as multifunctional platforms for city communication nodes; o "Perceive and Patch" Swarms of flying vehicles for autonomous inspection, diagnostics, repair and prevention of highway defects (e.g. potholes); o "Fire and forget" hybrid robots designed to operate indefinitely within live utility pipes performing inspection, repair, metering and reporting tasks.

Water companies manage extensive networks of clean and waste water pipes. Sometimes these pipes fail catastrophically, resulting in; loss of supply to properties, public highway closures and potentially long-term inconvenience to business and the general public. Pipes also frequently suffer leakage resulting in loss of pressure, increased demands on water treatment works (increasing carbon emissions) and water-related ground instability for example. The potential for pipe failure is, to some extent, controlled by ground conditions, in particular soil corrosion and stresses resulting from ground movement. This project is concerned with understanding the relationship between ground conditions and pipe failure so that we can attempt to predict where pipes are more likely to fail. The project will focus on the Yorkshire Water region and will take advantage of their pipe failure database. Locations where pipe failure has occurred will be analysed against data on ground stability, terrain and soil corrosivity sourced from the British Geological Survey. A conceptual model of pipe failure and a map showing predicted failure rate will be developed. The results of this project are anticipated to improve the ability of Yorkshire Water to plan their asset investment strategies for repair and maintenance. This will allow them to target investment to pipes that are most susceptible to fail, and thus use customer's money more efficiently. It will also reduce the frequency of catastrophic pipe failures, long-term leakage and reduce diffuse pollution caused by leaking sewerage pipes and infiltration of groundwater into pipes (causing combined sewers to overflow). Whilst this project is specifically concerned with the Yorkshire Water region, the results and/or methodology tested during this project are anticipated to be transferable to other water companies.

The underground sewer system in the U.K. is approximately 300,000 km long, for which the replacement costs are estimated to be 104 billion. The sewer system is owned by the privatised water companies who have a legal duty to maintain the structural and operational conditions of their sewer systems, and this includes reducing flooding incidents. In approximately 80% of cases, flooding incidents are caused by obstructions arising from the deterioration of a pipe wall, or from large deposits of sediment and/or fat. The detection and removal of obstructions should form part of any maintenance programme, although the ability to do this is currently restricted by the lack of a fast and reliable method. This project will focus on using sound waves to detect and characterise obstructions in sewers. Here, loudspeakers generate a pressure pulse that travels down a sewer pipe; this pulse is normally strongly reflected by any obstruction it encounters and by using microphones to capture the reflected energy information about the obstruction may be captured quickly and easily. Accordingly, this method offers a fast and objective way to monitor large sewer systems.The proposed research aims to deliver a step change improvement to a prototype acoustic device developed in a previous (experimentally based) EPSRC project (EP/D058589/1). The current device relies on cross-correlation between new acoustic intensity measurements and measurements stored for known sewer defects; however, this methodology is limited by the number of experimental studies it's possible to undertake and difficulties when interpreting measured intensity data. Furthermore, the current method can say nothing about the geometry, or surface characteristics, of an obstruction, and there is no proof that a unique link exists between the measured data and the properties of the obstruction. The proposed research seeks to address these issues by using mathematical models to aid in the development of a new measurement methodology that treats the acoustic intensity as a complex quantity rather than using the traditional real valued representation adopted in the current device. Here, complex acoustic intensity has the potential to uncover significantly more information from scattered sound fields when compared to a real valued intensity representation, and it is the measurement of complex intensity in acoustic waveguides that forms the focus of this proposal.Although complex intensity measurements have the potential to deliver significantly more information, they are not well understood, especially for scattering from obstacles in an acoustic waveguides. Accordingly, to gain a better understanding of complex intensity it is desirable to develop mathematical models and here both frequency and time domain models are proposed. The frequency domain model is based on the finite element method in order to accommodate those irregular geometries typically found in sewer systems; the time domain model is based on taking an inverse Fourier transform of the frequency domain calculations and will also utilise an inverse analysis in order to address issues such as the uniqueness of measured data. Theoretical predictions will be compared with time-averaged and instantaneous complex intensity measurements obtained under laboratory conditions. In this way, a more general understanding of complex intensity will be developed before this knowledge is applied to the development of a new measurement methodology for sewer systems. Furthermore, to maintain relevance to real sewer systems problems known to affect the accuracy of field measurements, such as manholes, cracks, joints and pipe surface roughness will also be studied. Accordingly, the understanding developed with the mathematical models and laboratory measurements will be used to develop a new prototype experimental methodology suitable for reconstructing the geometry and surface characteristics of obstructions in real sewer systems.