Newcastle University held its bi-annual symposium recently. Researchers from the university, who are part of the STREAM and WIRe CDTs, provided updates on their project along with outcomes to their peers and academic supervisors. The symposium offered students an opportunity to form new collaborations and network with their peers as well as the academic supervisors.
WIRe CDT runs from 2019 to 2027 with 60 students recruited across 5 cohorts.
Academic and Industrial affiliations: Cranfield University, Anglian Water, Thames Water
Title of research project: Securing drinking water supplies: the role of organic matter on water treatability
Globally, one in four cities is water-stressed, and the projected demand for water in 2050 is set to increase by 55%. The National Infrastructure Commission in the UK has estimated that an additional 1000 million litres of water per day (MLD) may be needed to secure the country’s water supply, which will be achieved through regional and national water resource planning. The Anglian Water (AW) region faces an acute water supply and demand gap due to low rainfall and rapid population growth, leading to expected water deficits of 35 and 145 MLD by 2025 and 2045, respectively. A strategic water supply network is being developed to transfer water from water-surplus to water-deficit regions, an increasingly used mechanism to improve drinking water resilience. However, the impact on water quality and treatability is unknown.
All source waters contain natural organic matter (NOM) that changes in quantity and character over time and space, so water transfers will invariably result in blends with different NOM characteristics and removal potentials by conventional coagulation and sorption processes. The hydrophobicity, molecular weight and charge control these processes and NOM characteristics also influence the downstream formation of potentially carcinogenic disinfection by-products. Thus, understanding NOM characteristics is crucial for effectively treating new water resources and blends.
Water utilities are relying on new sources of lower water quality due to revisions of abstraction licenses, increasing their reliance on surface waters. All surface waters in the AW region are from lowland catchments where NOM characteristics are not well understood. NOM has been well characterised in upland water sources, which has helped link it to treatability. For instance, UK upland sources have higher proportions of hydrophobic organic matter, which coagulation processes can effectively treat. In contrast, inputs of recycled wastewater and algal organic matter are more prominent in lowland areas, making NOM more hydrophilic and less amenable to coagulation. Currently, there is limited understanding of the characteristics of NOM in lowland surface waters that control their removal in drinking water treatment processes. This project will identify and match these characteristics with appropriate treatment methods to enhance their removal, allowing for the proactive development of strategies to treat these waters effectively for existing water treatment works and new ones that will be required.
Academic and Industrial affiliations: The University of Sheffield, Scottish Water
Title of research project: Unlocking the potential of hydraulic transients as a source of information about water distribution networks
A significant amount of water is lost in UK distribution systems as a result of leakage. With an increasing population and the added environmental pressures of climate change, managing our water resources is becoming more important. One aspect of water management is the reduction of leakage, a necessary element of which is leakage detection and localisation. Acoustic methods are currently the most popular for this purpose, however they have a reduced applicability in plastic pipelines due to low levels of acoustic transmission. An alternative method of leak detection more suited for plastic pipelines is the use of pressure transients. Pressure transients are generated in water distribution systems as a result of rapid changes in the velocity of water (e.g. pump failures and sudden valve operations).
Currently transient based methods aren’t commonly used in industry, largely as a result of system noise and unknown system configurations. This project aims to investigate new methods of analysing transient data which are capable of correctly mapping pipelines and reducing system noise. Once developed, this method will be validated in real distribution systems to detect and locate the presence of leakage.
Academic and Industrial affiliations: Cranfield University, Affinity Water
Title of research project: Soil as a core infrastructure to achieve catchment resilience
Climate change and increasing population in the drier south and east of the United Kingdom are critical challenges that the environment and the water industry face. In a water supply network that will be further strained, it is expected the south-east of England will require an estimated additional capacity of over 2000 Ml/d in a drought scenario, as the population is expected to rise by 51% by 2080. As 32% of the UK’s land is arable, optimising and improving water regulation within the soils of this arable land is paramount to securing future water supply and environmental protection. This is in tandem with the development of the Agricultural Transition Plan by the Department of Food and Rural Affairs, incentivising reduced tillage practices and supporting ground coverage of bare soil in non-growing periods of the year.
This project will assess if non-inversion tillage practices improve water transport in the soil during and near saturation, where percolation to groundwater leads to recharge. To do this, a range of field sites will be selected on the same soil type with similar climatology in the south-east of England. To estimate and compare the influence of tillage, multiple sites will be modelled using HYDRUS-2D/3D throughout the seasons, including the growth period using daily reported soil moisture data. Time periods of capillary percolation will be assessed noting the influence of in-situ preferential flow pathways developed from biological activity of undisturbed soil. When plot-scale estimations of the impact of tillage in the soil profile are complete, the next stage will be up-scaling plot-based conclusions to a broader groundwater catchment context, to estimate conclusions on implementation of reduced tillage practices on a wider scale across the south-east of England on arable land.
Academic and Industrial affiliations: Cranfield University, Thames Water, Anglian Water
Title of research project: Are ozone and granular activated carbon fit for purpose to meet current and future water quality challenges?
Ozone and granular activated carbon (GAC) drinking water treatment processes were implemented across parts of the UK water industry in the 1990s. Today, the equipment used to deliver the processes is reaching the end of its life and future challenges need to be carefully considered (emergence of micropollutants due to climate change and anthropogenic activities, regulatory changes). Hence the need to determine whether ozone/GAC remains the most appropriate solution. And if need be, would an enhancement of it, or an alternative process be able to address these forthcoming water quality challenges?
Furthermore, past studies have shown that the reaction of ozone with organic and inorganic components can lead to the formation of undesired by-products. With the exception of bromate, it is generally accepted that most oxidation by-products are adsorbed onto GAC. However, there is not a lot of evidence of that today. Therefore, this research project aims at determining how ozone and hydroxyl radicals change the adsorbability of micropollutants and natural organic matter (NOM) by-products onto GAC. In the next phase of the research, opportunities will be explored in order to build a model based on molecular structure that predicts the degradation of micropollutants using ozone or an hydroxyl radical-based process. The model could then be used as a tool to indicate for a certain chemical should it react with ozone? with •OH? should its by-products adsorb onto GAC?
Academic and Industrial affiliations: The University of Sheffield, UKWIR
Title of research project: Achieving biologically stable / low AOC water in the UK
Uncontrolled regrowth of microorganisms in drinking water may alter colour, taste, and odour, have health consequences for consumers and generate significant cost for water utilities. In this context, achieving biological stability is critical for water utilities to supply consumers with water that is both safe and aesthetically pleasing. The project aims to better understand and assess biological stability from treatment to tap, including the role of both water treatment and distribution on this process.
The project consists of three parts: historic data analysis, field, and laboratory work. First, analysis of large historic datasets from UK water utilities will draw out correlations between multiple parameters, identifying potential drivers and consequences of biological stability. Second, field work will compare the influences of different water sources, treatment processes and distribution practices on regrowth from treatment to tap in real world conditions. Finally, using a full-scale flow and temperature controlled experimental drinking water distribution facility, the role of biofilm on biological stability will be studied in three different nutrient conditions.
Academic and Industrial affiliations: Cranfield University, Thames Water
Title of research project: Resource and energy recovery from sewage sludge by optimised advanced thermal conversion process control
Rising uncertainties around the sludge-to-land route can result in disruptions to the current landscape of sludge disposal in the UK, and this is due to the concerns on harmful substances contained by sewage sludge. Pyrolysis is a promising sludge treatment method that provides new solutions to this complex situation, as harmful substances are eliminated at high temperature and the by-products from pyrolysis can be utilised for energy and resource recovery.
This project aims to assist the water industry’s decision-making of the adoption pyrolysis systems through pyrolysis testing, pyrolysis modelling, and techno-economics.
Five work packages are proposed. The first work package consists of reviewing and comparing the resource recovery options from sewage sludge pyrolysis. The second work package includes characterisation of varied sludges, pyrolysis testing, and the development of a predictive model for a generic pyrolysis process. The third work package involves the technoeconomics of the sewage sludge pyrolysis resource recovery plants, and the fourth work package involves comparing the different recovery routes using uncertainty and scenario simulation. The fifth work package consists of pyrolysis testing of sewage screenings as an alternative feedstock.
To date, the first work package presented that the potential recovery options from sewage sludge pyrolysis outputs are the upgrading of the evolved non-condensable gas, the condensed liquids, the char, or the whole vapour phase. The different potential products were compared in terms of specific yield, specific revenue, and other selection criteria including product potential, market assessment, and synergy within WWTP. The comparison revealed that the products with the least upgrading duty are the most desirable if to maximise gross profit.
Academic and Industrial affiliations: Cranfield University, Northumbrian Water, Anglian Water, Severn Trent Water
Title of research project: Ammonia to energy: A key decarbonisation strategy for the water sector
Treating the ammonia (NH3) present in wastewater prevents the eutrophication of aquatic ecosystems and lowers harmful emissions. Wastewater treatment plants convert NH3 to nitrogen in the presence of oxygen and microorganisms. However, the aeration required solely for NH3 treatment demands 1/5th of the treatment plant energy whilst collectively these plants consume nearly 3% of the UK’s total energy. Moreover, the nitrous oxide (N2O) generated as a by-product of treatment makes up over 15% of plant greenhouse gas emissions and has a global warming potential 300 times that of carbon dioxide. With the UK water sector committed to delivering a net-zero water supply by 2030, alternative treatment technologies with smaller greenhouse gas footprints are recognised as potential solutions. One such technology is the thermal vacuum stripping of NH3 from concentrated return liquor wastewater where NH3 is transferred from the liquid to vapour phase at low pressures. In this way, as much as 35% of NH3 in the plant is recovered as a valuable product rather than being abated using the conventional approach.
To develop thermal vacuum stripping for application in the water sector, this project will explore the poorly characterised vapour-liquid phase equilibrium compositions under vacuum pressure at low NH3-H2O concentrations. This knowledge better informs the design and operation of stripping units which are to be demonstrated from batch up to a larger scale continuous configuration. The project will also assess the unit techno-economic performance in relation to the quality of recovered NH3 product for green fuel application. Therefore, in addition to thermal vacuum stripping primary function of treating wastewater, using the recovered green fuel can reduce reliance on greenhouse gas emitting fossil energy powering the plant. Reliance is further diminished by decreasing energy-intensive aeration required during treatment which also consequently lowers N2O emissions.
Academic and Industrial affiliations: Newcastle University, Northumbrian Water
Title of research project: Minimising whole life carbon emissions in a multi-site utility
The overarching aim of the project is to develop a methodology for measuring and reporting all GHG emissions from operations, capital projects and the supply chain which is (or can be) embedded within Northumbrian Water (NWL)’s corporate systems/processes. The project considers and maps out the complexity of water infrastructure, including investment cycles and resilient infrastructure systems, using whole systems thinking and therefore covers a breadth of academic topics, including civil engineering, process engineering and environmental economics.
For operational emissions, the project aims to challenge the current reporting process to ensure that emissions factors/calculations represent best practice and satisfy or indeed advance the relevant national and international reporting protocols. Notably, the current methodology for calculating and reporting process emissions is relatively simple and only applicable to the UK water sector. Additionally, some Scope 3 operational emissions, such as those from chemical usage do not allow optimisation of the supply chain and therefore a few performance improvements are under delivered.
For embodied emissions, the company perceives a risk to its capital programme and its resilient infrastructures and a transparent and robust GHG emissions reporting needs to be delivered. It is anticipated that during Amp8 (2025-2030), NWL will be required to demonstrate GHG emissions within its project selection criteria for major schemes. The company will also need to be able to demonstrate estimated emissions at design stage vs delivered projects and account for the variance. NWL wishes to be able to demonstrate that its embodied emissions are calculated from data collected directly from our supply chain rather than national systems or using cost ratios.
In its current business plan, NWL has made the commitment that 60% of its expenditure will be with local suppliers. These suppliers are often small and therefore not equipped to report on emissions relating to their NWL contracts. Hence this project is also looking to develop a methodology to overcome this challenge.
Academic and Industrial affiliations: Newcastle University, Anglian Water, Northumbrian Water
Title of research project: Resilience of Groundwater Resource under Severe Drought
One of the dominating interests of water managers globally is the ability to predict the next major drought. However, drought is poorly defined with no universally accepted definition. This is due to several reasons. Firstly, drought is often the result of many complex processes acting on and within the environment. Secondly, drought is not a distinct event unlike a flood, and does not have a clear beginning and end as it is often interrupted with temporary periods of wetness. Therefore, drought is usually only recognisable after a period of time, and therefore can be difficult to predict before it is already happening. The impact of drought on groundwater is of particular importance as groundwater resources provide almost 50% of the global drinking water supply. Groundwater resources not only play an important role in meeting drinking water demand, it also is an important source of water for agricultural irrigation and to baseflow-fed rivers, lakes, and dependent ecosystems, maintaining flow during surface-water droughts. Consequently, due to the significance and reliance on groundwater resources, the impact of drought affecting them is a major concern and threat to water security, which needs to be addressed imminently.
Whilst modelling is an important process to understand the dynamics of groundwater under drought and the impacts it might create, model development has been focussed within specific fields and the integration of these separate models has been limited. Therefore, this project aims to address gaps in research and fully understand the response of groundwater resources to changing climate, the impact of pre-cursor conditions on drought magnitude and duration, and also aims to address a current issue which is the lack of an adequate model that can be used to consider and assess these issues. SHETRAN, a fully integrated, physically based, spatially distributed model, will be used throughout this project, focussing on areas of interest in the Chalk aquifer (Anglian Water) and the Fell Sandstone aquifer (Northumbrian Water).