For centuries, human activities have impacted our rivers by shifting the sources and combinations of physical, biological and chemical drivers and pressures. However, our understanding of their impact on ecosystems has been limited by viewing each in isolation and not considering their combined effects. Significant reductions in some regulated pollutants (such as nitrogen and phosphorus) have been achieved in recent decades. However, even with these improvements, we are witnessing declining water quality of our rivers, and the resulting loss of freshwater species and biota. The picture that we see is made evermore complex by the increasing numbers of different types of emerging contaminants of concern (e.g. pharmaceuticals, pesticides, illicit drugs, micro plastics etc.). This means that our freshwater species are being challenged by a bewildering combination of pollutant cocktails (mixtures) whose effects are poorly understood. At the same time, climate-change driven shifts in water quantity (more frequent floods, longer periods of low flow) and warming waters are expected not only to be influencing the function, physiology, abundance and biological timings of freshwater ecological communities directly, but also the delivery and potential toxicity of these cocktails respectively. It is not simply the water pathway that we need to consider, but also the re-mobilisation of contaminants and the changing patterns of exposure that potentially magnify the effects on biota (i.e. organism sensitivity). Our wastewater systems and combined sewer overflows transport these emerging pollutants from our cities and towns into our freshwater environment. Increasing urbanisation and changes in rainfall intensity and its seasonality, different catchment processes all have the potential to increase inputs of these emerging contaminants to the environment and freshwater species that live there. Substantial knowledge gaps remain around the effects of hydro-climatic and land use changes in combination with the different mixtures of chemicals on freshwater species. Our research will address these gaps by embracing the digital revolution through innovative technologies and transformative data analytics to deliver a step change in our knowledge and understanding. Our approach has three strands. The first will turn a spotlight on a typical catchment encompassing rural to urban land uses through rigorous investigations that will deliver high temporal resolution data. This will provide new understanding of acute/event-based impacts on freshwater ecosystems. Secondly, we will use national scale datasets and cutting edge data analytics tools to investigate the impacts of longer-term exposure to pollutant cocktails across the UK on water quality and ecosystem health. This will provide new understanding of chronic/long term impacts on freshwater ecosystems. Thirdly, we will integrate our new evidence base and understanding into a risk-based probabilistic model. The model will allow the exploration of the relationships between environmental change, declining river quality, multiple pollutants and ecosystem impacts. Our research will develop the evidence base to understand changing pollutant sources, delivery pathways and the environmental tolerances and boundaries within which organisms can thrive and flourish (i.e. the ecosystem safe space). Together, MOT4Rivers will inform priorities for policy, regulation and investment to design cost effective programmes of measures to promote and enhance sustainable freshwater ecosystems under a changing climate.

The water industry faces intensifying risks to its water treatment systems from rising dissolved organic matter (DOM) concentrations in upland raw water supplies. This is leading to rising treatment costs, drinking water quality breaches, and threats to existing infrastructure. Scottish Water (SW), the industrial partner in this proposal, working with CEH, aim to address this challenge by developing an entirely new approach to understanding, managing, and planning responses to DOM increases over the next 50 years in response to environmental change. This represents a radical departure from the current water industry focus on 'managing away' rising DOM levels in supply catchments through upland restoration, which has had only limited success. Risks and costs of rising DOM levels are widespread. They affect other water companies, including United Utilities, Welsh Water and Irish Water, who, alongside SW and academic partners (Universities of Glasgow and Leeds), will form the Project Advisory Board and ensure continued relevance and impact of the project. The project will build on a modelling framework developed by CEH and harness new scientific understanding to equip SW with: 1) state-of-the-art knowledge of the consequences of future environmental change for DOM levels; 2) a web-based Decision Support System (DSS) with which to anticipate where and when treatment-related thresholds are most likely to be breached; 3) the ability to more efficiently manage water treatment assets; and, 4) a robust, long-term strategic basis for sustainable catchment planning and optimised infrastructure investment. By developing these capabilities CEH will provide SW with tools to optimise mitigation (e.g. land-use interventions) and adaption (e.g. infrastructure investment) strategies. Proposed activities and (respective Work Packages) include: finalisation of SW needs and collation of SW data in a project database (WP1); development of an existing model framework to enable forecasting of future DOM quality, quantity and Key Performance Indicators (WP2); model implementation, focussed on circa 100 SW supply catchments (WP3), generation of a spatially explicit model of current and future DOM concentrations across the UK uplands according to climate change and air pollution scenarios (WP4); and, development of the DSS incorporating web-based tools, to provide a front-end for model outputs for use by SW, and enable forecasting of future annual average and seasonal extreme raw water DOM concentrations and quality, and Key Performance Indicators (KPIs) (WP5). Additional funding from SW will support collection of new data to assist in model parameterisation and testing. CEH will work with SW to implement the prototype DSS, initially for a subset of 'exemplar' sites to test and subsequently showcase the application of the tool, before scaling up to the full set of catchments from WP2. Consequences for SW's KPIs will then be assessed for a range of environmental scenarios and mitigation strategies. Results will be disseminated by a CEH in a series of briefing notes to SW and through the DSS directly. Exemplar studies will be presented to the wider water industry at the end-of-project dissemination meeting. At this point other water industry partners will be given the opportunity to engage in a future beta-test of the DSS, and work more closely with CEH and each other in developing further iterations and functionality. Ultimately, the project aims to transform approaches to rising DOM across the UK water industry, and potentially internationally. Project duration will be 18 months. During this time, SW will independently fund a parallel project of new data collection that will help to strengthen the empirical basis and parameterisation of the model to support future use. The total cost of the project, at 80%FEC will be £135,595, with £75,000 from SW to support supplementary sampling.

Clean drinking water is vital for human life. Water is also essential to agriculture, energy and manufacture. The United Nations recently reported an expected increase in demand for water of 55% by 2050. The reliable and sustainable provision of clean water for all is urgently needed worldwide, and is the focus of one of the Sustainable Development Goals established by the UN (Goal 6). In a scenario where conventional water resources are becoming increasingly insecure and contaminated, the development of new improved and resilient water treatment technologies is imperative to meet the UN's target. This proposal takes an important step towards a solution involving membrane filtration in water supply. Nanofiltration (NF) and reverse osmosis (RO) membrane processes are increasingly popular as they supply high quality water, including drinking water, from any available water source. A high pressure feed water is filtered through the membrane, producing permeate, i.e. clean water, whilst contaminants are retained on the feed side. Membranes are however known to foul due to an accumulation of contaminants on the membrane surface. Biofouling in particular, is caused by the accumulation, adhesion and growth of microorganisms on the membrane surface leading to dangerously reduced quality and flow of permeated water, increased operational and energy costs and membrane life reduction. Chemical cleaning regimes, such as chlorination, are used to combat membrane biofouling. These processes are inefficient and they require process downtime. They can also modify the properties of the membrane, ultimately reducing its life. This project will demonstrate a simple, novel cleaning technique to prevent biofouling formation on NF and RO membranes. We will explore the regular introduction of a burst of high salinity - a High Salinity Pulse (HSP) - into the input feed flow of the membrane. The HSP causes a high osmotic pressure difference to occur between the feed and permeate sides of the membrane. As a consequence, the direction of water permeation through the membrane temporarily reverses, flowing from the permeate side to the feed side. The membrane is backwashed and adhered microorganisms removed from the surface, avoiding growth and subsequent biofilm formation. This will maintain water production quantity and quality at lower operational and energy costs and extend the usable lifespan of a membrane, having an immediate transformative effect on industries where NF and RO membranes are used, which include the water, wastewater, aquaculture and food & drink industries.

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.

The UK water sector is experiencing a period of profound change with both public and private sector actors seeking evidence-based responses to a host of emerging global, regional and national challenges which are driven by demographic, climatic, and land use changes as well as regulatory pressures for more efficient delivery of services. Although the UK Water Industry is keen to embrace the challenge and well placed to innovate, it lacks the financial resources to support longer term skills and knowledge generation. A new cadre of engineers is required for the water industry to not only make our society more sustainable and profitable but to develop a new suite of goods and services for a rapidly urbanising world. EPSRC Centres for Doctoral Training provide an ideal mechanism with which to remediate the emerging shortfall in advanced engineering skills within the sector. In particular, the training of next-generation engineering leaders for the sector requires a subtle balance between industrial and academic contributions; calling for a funding mechanism which privileges industrial need but provides for significant academic inputs to training and research. The STREAM initiative draws together five of the UK's leading water research and training groups to secure the future supply of advanced engineering professionals in this area of vital importance to the UK. Led by the Centre for Water Science at Cranfield University, the consortium also draws on expertise from the Universities of Sheffield and Bradford, Imperial College London, Newcastle University, and the University of Exeter. STREAM offers Engineering Doctorate and PhD awards through a programme which incorporates; (i) acquisition of advanced technical skills through attendance at masters level training courses, (ii) tuition in the competencies and abilities expected of senior engineers, and (iii) doctoral level research projects. Our EngD students spend at least 75% of their time working in industry or on industry specified research problems. Example research topics to be addressed by the scheme's students include; delivering drinking water quality and protecting public health; reducing carbon footprint; reducing water demand; improving service resilience and reliability; protecting natural water bodies; reducing sewer flooding, developing and implementing strategies for Integrated Water Management, and delivering new approaches to characterising, communicating and mitigating risk and uncertainty. Fifteen studentships per year for five years will be offered with each position being sponsored by an industrial partner from the water sector. A series of common attendance events will underpin programme and group identity. These include, (i) an initial three-month taught programme based at Cranfield University, (ii) an open invitation STREAM symposium and (iii) a Challenge Week to take place each summer including transferrable skills training and guest lectures from leading industrialists and scientists. Outreach activities will extend participation in the programme, pursue collaboration with associated initiatives, promote 'brand awareness' of the EngD qualification, and engage with a wide range of stakeholder groups (including the public) to promote engagement with and understanding of STREAM activities. Strategic direction for the programme will be formulated through an Industry Advisory Board comprising representatives from professional bodies, employers, and regulators. This body will provide strategic guidance informed by sector needs, review the operational aspects of the taught and research components as a quality control, and conduct foresight studies of relevant research areas. A small International Steering Committee will ensure global relevance for the programme. The total cost of the STREAM programme is £9m, £2.8m of which is being invested by industry and £1.8m by the five collaborating universities. Just under £4.4m is being requested from EPSRC