For the existing water treatment processes, difficulties in removing humic substances (HS) to improve drinking water quality, and safety, have created the demand for exploring novel options to enhance HS removal. Here a combination of solar irradiation and granular activated carbon (GAC) adsorption is proposed. It aims to make use of the most freely available and abundant energy source, sunlight, to improve the performance of GAC adsorption process. An investigation into how characteristics of HS vary under natural sunlight and how this influences the subsequent removal of HS by GAC adsorption was carried out. Bulk water parameters, and more specifically, UV absorbance at 254 nm (UV254), as well as dissolved organic carbon (DOC) were used in conjunction with molecular weight (MW) to evaluate the performance of the solar-GAC method. The observation was made that solar irradiation led to a decrease in DOC, UV254 and MW of HS. The high MW components were photodegraded into smaller molecules, even with very low solar intensity in winter. Significant photodegradation of small molecules was also achievable by exposure to natural sunlight alone. Pre-treatment using solar irradiation was shown to successfully improve the GAC adsorption performance on HS removal, increasing the DOC removal from 69 % to 95 %. An up to three-fold increase in the adsorption capacity of GAC for the irradiated HS was observed. Solar collectors were found to effectively enhance the photodegradation of HS, and consequently enhance the removal of HS by GAC adsorption. The application of solar collectors could be a viable option for humic water treatment. The proposed solar irradiation-GAC adsorption method provides a new approach for the treatment of humic rich waters. The utilization of solar irradiation in water treatment processes is considered a sustainable and promising field.

This thesis explores how water infrastructures can be reconfigured in the urban environment to the advantage of human society in the future. It found actor-network theory co-evolutionary pathways between current material configurations and social practices for these reconfigurations. Material configurations include infrastructures, urban form, fixtures, fittings, and water types. Social practices, include existing behaviours, imagined behaviours, desires, and aspirations. This is an important question to answer because there are many places around the world, both in developed and developing countries that currently face inadequate water supplies to serve the needs of their ever growing populations, or conversely flooding due to extreme precipitation or sea level rise. The lower Lea river basin in London is one such area. The large scale engineering solutions of pipes and pumps to control water that have been the typical solution are reaching their limits therefore it is imperative to find other means to manage water in urban environments. This research used an actor-network theory co-evolution framework to understand the existing urban water-cycle, and to find areas of transformation in order to develop actor-network coevolutionary pathways for change. Interviews, group discussions and water diaries were used to investigate the existing conditions and anticipated future changes of both private citizens and water professionals. An iterative process of design synthesis and discussions were repeated twice to test and define the actor-network theory co-evolutionary pathways. This research stretches actor-network theory from its ethnographic beginnings into the realm of the future through design propositions. It found that there were two strongly favoured actor-network theory co-evolutionary pathways for reconfiguring the urban water-cycle in the lower Lea river basin. These were increasing freshwater productivity and transforming waste to resource. These create new water-cycle assemblages that offer advantages to people who face many, yet uncertain, types of water stress in the future.

The increasing number and scale of river impoundments throughout the 19th and 20th centuries means that the management of these impoundments is crucial to the future of global riverine biota. Impoundments such as reservoirs can affect rivers in a variety of ways, not least through the reduction in amplitude of the natural hydrograph, depriving rivers of ecologically important spate flows. Many reservoir operators conduct regular safety tests, known as scour releases, during which large quantities of impounded water are released directly into rivers. This project assesses the impact of these releases on the hydrology and physio-chemistry of the receiving water bodies as well as upon fish movements and benthic macroinvertebrate abundance and diversity downstream of the reservoirs. The potential of such releases to mimic natural spate flows for ecological gain is also examined. The work took place in the Yorkshire Water catchment area in northern England between 2007 and 2010. Passive Integrated Transponder (PIT) telemetry was used to assess the responses of brown trout Salmo trutta to these short-duration releases. Tagged fish were able to maintain position during the releases and showed no evidence of wash-out or upstream migratory movements associated with the releases. Changes to macroinvertebrate abundance, diversity and community structure associated with the release were also examined. Some sites showed significant wash-out and community change following the releases while other sites were unchanged. Communities at impacted sites returned to pre-release structures within weeks of the releases. Analysis of habitat use and characteristics suggest the responses of fish and macroinvertebrates to these reservoir releases were linked to habitat heterogeneity and the use of flow refugia. The negative impacts associated with the scour releases were minimal, while mimicked spate releases may improve salmonid spawning habitat and could re-introduce valuable flow variability to impounded catchments.

No description available.

Mineral scaling poses a far greater problem to any industry that uses or produces water. The quality of water used by industry varies widely and gives rise to numerous scaling problems. Mineral scale formation and deposition on equipment surface causes major flow assurance concerns particularly apparent in the offshore oil and gas industry. An improper of scale management programmes could lead to a rapid mineral scale build up and subsequently significant reductions in productivity and compromises the operational safety of process equipment (i.e. safety valves) as a result of blockage. The result is costly workovers increasing project operating costs (OPEX) due to the need for scale dissolver treatments and significant production losses. As part of scale management programme, it is desirable to be able to quantify the extent of the mineral scale that has deposited on component surface and also to be able to monitor the changes of likelihood that a production fluid will precipitate out mineral scale. The nature of this research is focus on exploring a simple approach or a methodology to detect the mineral scale formed specifically for calcium carbonate on the electrode surface. The application of a submerged impinging jet (SIJ) in conjunction with an electrochemical technique was developed. The development of this technique has been taken into the consideration of advantages and disadvantages of the current available scale detection techniques. Not only has the complexity of equipment and facilities been considered during the development stage, but the data interpretation of the existing technologies has been considered. In general, efforts have concentrated upon strategies to develop and to validate this methodology for the scale coverage on the electrode surface as well as monitoring the scaling tendency through the electrochemical technique measurement. Various verifications and experiments were undertaken to ensure the reliability of the use of electrochemical measurement and SIJ geometry configurations. The influence of surface condition on the sensitivity of this technique were also assessed This technique clearly demonstrated that various levels of mineral deposition on the surface could be quantified. This included the calcium carbonate deposition in the presence and absence of magnesium ions. In this study, a similar SIJ set up configuration was used for scaling tendency measurement to quantify and predict whether scaling will occur in water or brine solution. The scaling tendency results illustrated that there was a good correlation between the saturation ratio and the scaling tendency slope measurement by an electrochemical analysis. The contribution main of this research contributes to a better understanding of the used of SIJ for scale detection, monitoring and quantification of calcium carbonate scale formation.

Biofouling is both a human health hazard and detrimental to process efficiency. Biofilm growth is inevitable on exposed surfaces, so an informed approach to cleaning and timely management are essential. Chemicals can readily kill cells, but the biofilm structure must be removed to prevent re-growth and maintain sterility. Chemical agents also pose health and environmental risks, but the typical alternative is to pump unsustainable volumes of cleaning solution through pipelines for mechanical cleaning. The aim of this research was to apply green cleaning principles to biofouling removal in industry, reducing the amount of chemicals, water and energy used in cleaning. Biofilms of Escherichia coli and Burkholderia cepacia were grown on polyethylene, glass and stainless steel 304, in single and mixed species cultures. Fluid dynamic gauging (FDG) utilises hydrodynamics to measure both the thickness and attached strength of the biofilms and therefore the optimum water usage for removal can be estimated, and is both relatively simple and inexpensive to operate. As well as using a static culture method, a drip flow reactor was built to develop biofilms under flow conditions. The use of FDG offers an original way of monitoring both the attachment strength and thickness of mixed species biofilms, and drip flow is an alternative to traditional biofilm growth methods for analysis of removal behaviours, with particular relevance to food production environments. The adhesive and cohesive strengths of both single and mixed species biofilms increased up to 14 days’ growth, and as previous studies suggest that this will be sustained over longer periods under flow conditions, cleaning prior to peak strength would be prudent – at later stages the risk of pathogens developing and contaminating the process would likely become too great, particularly if the biofilm is experiencing significant detachment which increasingly occurs with age. The development of greater, sustained thickness over time can also pose problems with heat transfer and enhanced pressure drop. Protein, a key component of the extracellular matrix, showed a strong correlation with the adhesive strength of mixed species biofilms. Biofilms grown on polyethylene attached more strongly in the early stages of growth than those on glass or steel, which may be due to the greater hydrophobicity of the surface. Chemicals can be used most effectively to weaken the outer layers, and sodium hypochlorite was also shown to be useful for weakening surface adhesion – the required shear stress for 95% removal was reduced by approximately 60% for 5 and 10-day old biofilms. There are more risks associated with chlorine-based disinfectants than the alternative, peracetic acid, although finding a suitable low concentration would be simple using this method. There is no simple solution, complicated further by the unpredictability of the species present in industrial biofouling. The best way of minimising the risk of spoiling and contamination would be to clean surfaces with regularity, in the region of every 5 days rather than after a more prolonged period, which would also serve to minimise the resources used by preventing biofilms from becoming too strongly attached or too thick. A chemical input would need to be determined by testing for the optimum concentration necessary for a suitable effect, thus eliminating excess use, and thereby reducing water and energy use in the process. Taking a multispecies sample from a process flow could offer a more realistic approximation of industrial biofilms. Surface coatings to prevent adhesion are the focus of much research, and could be an alternative to reactive methods.

The detection of emerging environmental contaminants at trace levels is a huge challenge for analytical research, and when expensive laboratory equipment is required, it is essential to provide a cheaper method that can ultimately undertake real-time sampling, whilst maintaining the sensitivity and reliability of current monitoring procedures. Electrochemical methods are a suitable candidate and studies into the development of submicron-gap generator-collector electrodes are provided alongside a variety of electrochemical methods. The aim of this project is to fabricate novel, low-cost, electrochemical devices with the potential for development into sensors for water quality monitoring. Nitrobenzene, Phosphate and Hydroquinone are the analytes used as they have well-known redox pathways and are known environmental pollutants and/or markers for other emerging contaminants. Initial studies examine the use of square wave voltammetry experiments in generator-collector mode, to provide information on either the fully reduced species or the intermediate species, depending on the buffered conditions used, with a view to detecting short-lived intermediates. Drawbacks with electrode geometry see the development of junction electrodes with larger active areas for greater sensitivity and changes in electrode materials for more robust device with a wider potential window. Generator-collector electrodes are also demonstrated as devices in electrochemical flow injection and for anion transfer at a triple phase boundary.

This thesis argues that socio-technical systems (STS) mediate between governance and the vulnerability of households. A STS approach enhances the analytical categories of the sustainable livelihoods framework: by conceptualising STS as the groups through which risk is shared, household task, infrastructure and governance to be brought into a single conceptual space. The thesis develops a methodology, based on the sustainable livelihoods framework and the World Health Organisation's water system indicators, that captures the features of STS which help households to buffer vulnerability. These methods are applied to an empirical study of Cusco, Pern and three urban case studies: San Bias, near to the city's main plaza and served by the provincial water company Angostura, a pen-urban settlement with its own water system and Manco Capac, with a dilapidated, independent supply. Livelihoods were vulnerable to seasonal, local and global cycles with San Bias linked to tourism Angostura exposed to annual flooding and Manco Capac constrained by low, seasonal incomes. Diversity and complexity in livelihoods---exposure to different risks at different times---enhanced the ability of people in San Bias and Angostura to mitigate risks, while, in more homogeneous Manco Capac, existing vulnerability was interacting with poor water, sanitation and other services to compound the tasks faced by those with weak household assets. The physical hardware and institutional software of water systems contributed to differences in household vulnerability. Their modes of organisation, categorised as privileging, bypassing, resisting and networking, were dhven both by governance, through policy frameworks and local institutions, and livelihoods, where socio-technical systems react to the perceived hsks and returns of livelihoods and groups of livelihoods. Sustainable livelihoods, which enhance rather than damage livelihoods of others, are undermined by bypass but bolstered where assets are complex and diverse and modes of organisation serve to network users and providers, citizens and government and contaminators and contaminated.

Within recent years, technological advances and stricter regulatory requirements have seen the increased use of automation and instrumentation within the wastewater treatment industry. As a result, advanced control strategies are required, to fully exploit the potential of these complex systems in addressing water quality concerns. Model based control strategies can be appropriate within the multivariable constrained wastewater system. In particular, the inherent model based nature of this approach can be valuable in the prediction of the treatment plant effluent quality required over a considered time period, to meet water quality standards. Multivariable linear predictive control is implemented for a benchmark treatment plant model, demonstrating the constraint handling ability of the predictive control structure. The limitations of an effluent-based control strategy in the maintenance of river quality is discussed. A more global approach to wastewater control must be considered in order to compensate against disturbances within the system. Tackling this concern, the incorporation of receiving water quality objectives within the control strategy is proposed. To this end, the application of linear MPC to the control of dissolved oxygen concentrations in the receiving waters under storm conditions is demonstrated. The drawbacks involved in a linear model based approach within a nonlinear urban wastewater system are considered. Several nonlinearities are present: the bioprocesses involved are by definition nonlinear, and are affected by varying wastewater load and characteristics. These can be the result of varying stormwater effects upon the treatment plant or emergency overflows to receiving waters. This therefore motivates the development of nonlinear strategies in the control of the wastewater processes. The control of SISO nonlinear processes within the urban wastewater system, such as dissolved oxygen, is demonstrated via the use of fuzzy gain-scheduled and Wiener model based predictive control. Additionally, the use of existing nonlinear process models in the control of wastewater processes is shown in the application of state dependent model predictive control.

Uncertain and complex environmental legislation governing the management of water resources has presented significant challenges to those responsible for identifying investment options to manage potable water supplies. This study aimed to develop a decision support process to enable a UK water company to understand and characterise the complex and uncertain implications of the Water Framework Directive (WFD) on the management of potable water supply. A flexible, exploratory and participatory approach was adopted, and included a central reference group comprised of managers representing different departments within the water company. Semi-structured interviews, informal discussions, focus groups, field visits, water company data, academic and legislative documentation, as well as UK water sector literature and observations by the researcher provided data which informed the criteria for and the population of a new Bayesian Network (BN) based Hybrid-Decision Support Process (Hybrid-DSP). Using BNs as a basis for decision support allowed the integration of diverse variables, as well as identifying and representing the relationships between them. The visual representation that BNs provided of the interrelationships between the variables, facilitated organisational learning in relation to the implications of the WFD for potable water management, which led to clearer identification of potential organisational responses. This study demonstrates the practical implications for the use of BNs within a water company in the UK. Furthermore a new BN based Hybrid-DSP has been developed through this study, which offers a systematic and holistic template to identify and analyse water company responses to the implementation of environmental legislation.