MSc & MSc Funded Theses

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Open Access
Agricultural challenges today and in the future: the beneficial role of agroecology
(Cranfield University, 2009-09) Keay, Gordon; Villa, Raffaella
Interest in agroecology is growing as evidence mounts that conventional agricultural methods are unsustainable, degrading the resource base (e.g. soil, water, crop diversity, biodiversity etc.) on which they depend. Alternative ways to produce foods that build soil fertility, protect ecosystems, conserve biodiversity and reduce energy inputs, provide the possibility of long-term productivity and ecological sustainability. The International Assessment of Agricultural Science and Technology for Development (IAASTD) have supported agroecology as a key set of solutions for world agriculture, which synergistically tackle development, sustainability and conservation goals. This study presents indicators to measure the sustainability of an agricultural practice which, placed in a hierarchical pyramid, demonstrates their importance and interconnected relationships. A comparative evaluation of agroecological and conventional systems is shown to assess the effects of management practices on the indicators. Agroecological approaches differ from conventional ones as they aim to sustain the soil and ecosystems by reducing synthetic inputs and creating alternative natural processes to maintain soil fertility and manage pests. Soil fertility is the essential indicator of sustainable agriculture, it was shown to improve in agroecological systems, indicated through increased soil microbial biomass (60% higher than in conventional agriculture) and earthworm abundance (up to 88% higher than in conventional agriculture). The loss of biodiversity due to current intensive farming practices is an indicator of unsustainability. In the agroecological systems biodiversity was shown to be comparatively higher. The diversity of bird and beetle species were recorded to be 50% and 38% more abundant respectively, and bat activity was shown to be 60% higher. These are bio-indicators of sustainable agriculture. The reduced chemical inputs led to an average of 50% less energy used on the agroecological systems. The resulting effects on yields showed great variation. One long term trial showed a 20% yield reduction in the agroecological system. Yet in times of drought, when advanced cropping systems were implemented, in developing countries yields were shown to be comparable, often significantly higher. This study provides solid evidence that the world’s future food security lies in the hands of sustainable agricultural practices. Agroecology demonstrates techniques that can be used towards reaching this vital goal.
Open Access
Assessment of an innovative soil aerator on soil physical disturbance and reducing runoff on compacted grassland
(Cranfield University, 2009-09) Shanahan, Peter; Simmons, Robert W.; Hann, Michael J.
Poor grassland management practices increases compaction and reduces infiltration leading to increasing risk of poaching and runoff generation. On-site impacts of grassland compaction include the loss of topsoil structure which also reduces soil ecosystem functioning. In addition, ongoing diffuse water pollution from compacted grassland limits the ability of the UK’s authorities to meet EU water quality guidelines such as the Water Framework Directive and address flood risks in areas of extensive grassland management (e.g. Boscastle, 2004). This study investigates the effects of an innovative ground-driven rotary soil aerator at alleviating soil compaction and reducing overland flow (designed by Mr. Roger Clay, Herefordshire). The magnitude of soil disturbance from slotting was assessed at the Cranfield University Soil Dynamics Test Centre soil-bin. Draught and vertical force requirements and tillage efficiency were also determined for varying depth and horizontal and vertical angle combinations using an Extended Octagonal-Ring Transducer (EORT). The effect of various slotting treatments on runoff was then investigated on a steep compacted permanent pasture in Herefordshire using erosion plots and simulated rainfall. From the soil-bin assessment, soil disturbance was most efficient (lowest specific draught) at 100 mm depth, a vertical angle of 18° and with increasing horizontal angle (0° to 10°). The draught requirement for a single bladed disc at 18° vertical ranged from 0.88 to 1.24 kN (90-126 kg force) and a maximum vertical force or ballast requirement of 257 kg force per bladed disc. Slotting treatments reduced runoff by 75% as compared with the non-slotted control.
Open Access
A benchmark study of the independent quality validation techniques of product design and development
(Cranfield University, 2009-09) Adeniji, Moyosore; Al-Ashaab, Ahmed
As we move ahead in the 21st century, quality validation techniques need to be based on principles of long term safety as consumers are now more aware of safety issues surrounding product design and development and globalisation has brought about competition within the manufacturing industry. Quality is seen as a reality for all manufacturing organisations and if quality standards are ever compromised, the immediate benefits in terms of cost savings, efficiencies and enhanced profitability are often lost. The study aims to capture and analyse the industrial best practices of independent quality techniques to evaluate and validate product design and development. The project introduces various techniques used in testing hardware components of products and what the pros and cons of these testing techniques are. Due to the information that was to be gathered during the research process, an inductive approach was taken. This approach consisted mainly of five major phases; the literature and industrial research, data collection & analysis at the sponsor company, the benchmark study, the final proposal and validation of the project by experts at the sponsor company. Academic literature and various online resources were consulted and reviewed to identify the various hardware testing techniques and for overall insight into the common issues and challenges faced by manufacturing organisations involved in the use of the identified testing techniques. Comparisons were made between academic literature and reality in industry. The results revealed that the sponsor company was operating within the best practices of the manufacturing industry and conclusions were drawn from the entire study stating that although the sponsor company was operating within the best practices, there was room for improvement. The documented benefits of the testing techniques will provide factual information to the senior management team enabling them make strategic decisions on the new techniques that could be implemented into their hardware testing plan.
Open Access
Beyond narrative: modelling metaphor in environmental discourse
(Cranfield University, 2009-09) Naughton, Linda; Cook, Matthew
This project aims to bring together ideas from a wide range of disciplines with the objective of exploring the use of metaphor in environmental discourses. It looks beyond the narrative form of story-lines to construct models of discourses by representing processes as spatial arrangements of content. The subject to be explored is the competing discourses of economic growth and sustainability, an area which continues to generate much debate but little change in economic policy. The current dichotomy of views representing the pursuit of growth as somewhere between essential to social stability and the root of all evil has prevented a move towards consensus in the debate. This study aims to explore the ways in which an analysis of metaphor within the discourse could open up possible conduits towards the goals of sustainability.
Open Access
Characterisation of the transcriptional potential of intergenic CCG-repeats
(Cranfield University, 2011-08) Cozens, Jacob; Jones, Christopher
CCG repeats have been found to have a non random distribution throughout the human genome. Previous analysis of ChIP-seq data from 800 intergenic CCG-repeats shows that they are associated with RNA polymerase II and several histone modifications that characterise transcription initiation including H3K4me3. RNA polymerase II, H3K4me3 and nucleosome distribution profiles have been analysed at these repeat regions using computer programming techniques. These profiles have in part been found to be similar to those observed at transcription start sites and so this raises the potential for CCG repeats to be implicated as alternative sites for transcription initiation.
Open Access
Desalination technologies for developing countries: what solutions?
(Cranfield University, 2009-09) Groult, Lucille; Tyrrel, Sean
Desalination is a water treatment option known by people at large for its large scale use in rich countries such as in the Middle East. Nevertheless, this is not an option for some developing countries such as Kenya, as, due to the water scarcity existing in such places, saline water is the only source for drinking purposes. Numerous technologies exist for desalinating water, from the very simple process of solar desalination already in use in the antiquity, to the most complicated membrane or electronic technologies. Appropriate solutions adapted to development or emergency situations have to be taken depending on the context in place in developing countries. Through discussions with private companies and research laboratories, some of the most up to date systems currently usable have been reviewed in order to assess their suitability for an implementation by the charity Oxfam GB in a near future in several locations in West African and South Asian countries. Criteria have been defined according to the needs observed by the charity in targeted places, better targeting possible appropriate technologies. The study focused on technological details as well as long term management issues for optimising ownership of the local communities. After comparison of the reviewed technologies and confrontation with the defined criteria, it resulted that interesting options available for development are membrane-based or distillation. The use of clean energy sources such as brute strength (mechanical systems using animal or human strength) simplify operation and maintenance, and lower operation cost at the same time for a sustainable implementation in remote villages. Automated electronic-based systems are also an opportunity for emergency situations. However, most of those solutions have not been in use in a developing country yet. Consequently, innovative experimentation is needed for the good of all.
Open Access
Determining the carbon footprint of a National Trust country estate
(Cranfield University, 2009-09) Slater, Dora; Burgess, Paul J.; Williams, Adrian
The UK Government aims to reduce greenhouse gas emissions by 80 % by 2050 against a 1990 baseline. Agriculture makes up around 7 % of UK emissions and the industry is under pressure to meet these targets (and to produce more food). To achieve reductions it is necessary to be able to calculate emissions. This study looks at methods to calculate the carbon footprint of a National Trust estate with livestock, arable farming and a stately home. Methods explored include greenhouse gas inventories, life cycle analysis and carbon calculators. A carbon calculator designed for farms was selected (the CALM Calculator) and applied to Wimpole Hall, Cambridgeshire. Key greenhouse gas sources were identified and estate activity data gathered to calculate the footprint. A comparison was made between current arable practices and proposed organic methods. Emissions from estate energy and water consumption were also included. The arable non-organic farm emitted 1018 tCO2e, 73 % due to N2O emissions from nitrogen fertilizers. The livestock farm emitted 686 tCO2e, 44 % from cattle. Estate emissions from electricity, heating oil and water supply were 303 tCO2e. The total estate footprint was calculated as 2007 tCO2e. A change to organic arable methods was predicted to deliver an estate footprint of 1361 tCO2e but yields will be less (organic wheat is said to yield only 68 % of non-organic). The removal potential of conversion of areas of arable to grassland (41 tCO2e) and particularly of farm woodland (1430 tCO2e) was noticeable. Combined these can offset 73 % of total estate emissions using non-organic arable methods and 103 % of total estate emissions using proposed organic arable methods. Shortcomings of the method are identified along with the high level of uncertainty connected to the results. The issue of reduced yield expected under organic arable cultivation is highlighted and the implications of balancing reduced emissions with maintaining food production are explored.
Open Access
Development of a framework for assessing the economic benefit of remanufacturing
(Cranfield University, 2009-09) Jakpa, Onome, E.; Xu, Yuchun
Product waste is becoming a big problem in our life. In order to reduce waste and efficiently use resources, product can be remanufactured, and its materials can be recycled to achieve better sustainability. In comparison with recycling materials, remanufacturing products can retain all the value added, so potentially it has high profitability and sustainability. Despite its main advantage of retaining the value of the products, remanufacturing is an area that is not widely practiced due to the high costs of remanufacturing and reverse logistics facilities. As a result of this, the cost components had to be researched in order to ascertain the costs involved in the process of remanufacturing. The identification the cost drivers in each of the process provided the basis for a generic framework to be developed which gives remanufacturers a template to determine the economic benefits of remanufacturing from a whole systems point of view including the reverse logistics. Through the use of a specified methodology, this research aims to capture all the costs involved in the whole systems remanufacturing process given that the previous models that exist do not propose a costing model for both reverse logistics and remanufacturing. Ready to Use Additive Manufacturing – RUAM is a technique for creating robust three dimensional metal objects. It is application in the framework allows for the refabrication of EOL products.
Open Access
Drinking water quality and treatment practices in Pabal, India
(Cranfield University, 2009-09) Mukadam, Aisha; Webster, James
The drought prone, rural village of Pabal is an example of improved access to water through a piped water system, however at times the villagers are also recipients of a poor water quality supply. Prevailing illnesses of diarrhoea and gastro-intestinal diseases, especially during the monsoons result in 40-50 % of villager‟s income being spent on medical bills. This research project provided by Engineers Without Borders – UK and EngINdia aims to form an investigative study into the current water quality and treatment methods in Pabal. This was achieved by analysing water samples using the DelAgua Water Testing Kit for microbial pathogens (faecal origins) at different points in their distribution system as well as carrying out a social survey through 22 questionnaires and a few target interviews. Results showed the reservoir water source to be highly contaminated but chlorination at the storage tank removed all traces of thermotolerant faecal coliforms. However all consumer points were also found to be contaminated as well as at the borehole hand-pump. Qualitative data collected through observations, sanitary surveys and the questionnaires provided possible reasons for contamination. The pipeline is in disrepair through lack of maintenance, pollutants and effluence (human and animal) are leached into groundwater and pipe supplies, as there are also no drainage or refuse systems in the village. Most villagers are aware and practice basic health, sanitation and water treatment however some only treat once they fall ill. Water treatment is essential in Pabal at all times and should be implemented at a cost-effective household level. The villager‟s health may be safe guarded by utilising traditional methods such as cloth filtering, copper pot storage (anti-bacterial properties) in addition to chlorination. Further education and future water treatment designs based on biosand and UV filtering can be produced locally via the community involving educational centre Vigyan Ashram.
Open Access
The effects of a thermal conditioning treatment forweed control upon soil biological properties
(Cranfield University, 2009-09) Amis, K. S.; Ritz, Karl.; Pawlett, Mark
Weeds, and their associated control, are often significant in limiting production within organic farming due to restrictions on herbicide use within such systems. Organic farmers rely on alternative weed control methods, including soil thermal treatments. Preliminary research has shown soil steaming to be a potentially effective weed control method, but procedures have yet to be fully explored and implemented. One issue is the effect steam treatment has upon the non-targeted components of the soil system. This study considered the magnitude and persistence of the effects that soil steaming had on biological aspects of soil systems within the organic production of Daucus carota, sativus (L) (carrots). A field-based study was conducted whereby soil treated with steam was sampled at intervals of 1 hour, and 14 and 42 days following treatment. Impacts upon the soil system were then assessed by measuring a range of chemical and biological properties related to carbon and nitrogen cycling. Immediately following steaming, actual nitrification was inhibited with an associated accumulation of ammonium-N, displaying an initial low resistance to the thermal treatment. However, recovery of this process was apparent at approximately 14 days post-treatment with a significant rise in both nitrate-N and potential nitrification, indicating a degree of resilience of the nitrification process. Overall, other measured components of the soil system, including microbial activity and organic carbon, also demonstrated signs of resilience, indicating that the system still had the ability to function and provide its regulatory and provisioning services within the short-term following soil steaming treatment.
Open Access
Enabling the development of a sustainability best practice library
(Cranfield University, 2009-09) Nazir, Amir; Al-Ahsaab, Ahmed
Global environmental problems, rising energy prices, lack of raw material availability, increasingly demanding legislation and costly environmental taxes are some of the reasons that drive company policy towards adopting sustainability concepts and practices. This MSc thesis project aimed to carry on the research of industrial sustainability best practices in order to have a detail documentation that will aid the development of digital library. This is to help companies like CEMEX and their stakeholders to increase their sustainability awareness and enabling them to embed best practices in their operational processes. The research lacked clear and coherent method for mapping best practices from the literature into the adopted sustainable development process without validation. Nevertheless recommendations included proposing a separate study for the implementation of the sustainable development process and a further pilot study into implementing a few key best practices within industry. Overall this study was successful in helping to identify and validate best practices that were most frequently mentioned by academics and to some extent reflected the existing state of affairs concerning sustainable development and the environment.
Open Access
Evaluating the potential of anaerobic waste stabilisation ponds for wastewater treatment in a temperate climate
(Cranfield University, 2009) Ansari, Ilyas A.; Jefferson, Bruce
A pilot scale baffled anaerobic waste stabilisation pond (aWSP) was designed based on an organic loading of 0.17 kg COD m-3 d-1 to evaluate the potential of aWSP as a passive, sustainable technology for domestic wastewater treatment in temperate conditions. After 4 weeks of operation and up to 45 days (end of study), average removals of 37% COD, 30% BOD and 36% suspended solids were observed which compares to the literature surveyed for aWSP treating domestic wastewater. A linear correlation between COD removal and time since start-up was observed and compared favourably to an anaerobic membrane bioreactor (aMBR) that was started up unseeded. Seeding the aWSP apparently augmented start-up and whilst higher COD removal for aWSP have been reported, it is anticipated that continued operation (>45 days) will yield further efficiency improvements. Methane reported in the gas and liquid phase was approximately 4.1% and 5.7 mg l-1 respectively suggesting relatively low production of methane. However, this does demonstrate that methanogenesis occurred soon after start up. Using this data to model a 5000 PE site, total energy output of 62 MWhy-1 (electricity and heat) was generated and only 6 MWh y-1 (electricity) consumed, this compares to an equivalent conventional activated sludge process (ASP) which uses approximately 655 MWh y-1 electricity for aeration. Results to date suggest that aWSP technology represents a viable sustainable alternative for domestic wastewater treatment in a temperate climate versus traditional high energy technologies.
Open Access
An evaluation of the restoration programme for a cut over section of Wedholme Flow raised mire
(Cranfield University, 2008-09) Lewis, Graham; Howden, Nicholas J. K.
Wedholme Flow, Cumbria is the site of the largest lowland raised mire remaining in the UK. It forms part of a group of ombrotrophic mires known as the Solway mosses, situated in the north west of England. As with all remaining raised mires in the UK, Wedholme Flow has suffered some historical degradation largely caused by cutting of peat at the site’s periphery for fuel. More recently large sections of the mire surface have been commercially mined mainly for horticultural use. These include sections which have been cut over by hand leaving baulks or upstanding strips of unmolested peat between cuttings but also sections of the mire surface that have been strip mined or milled using machinery. Because of the complete loss of Sphagnum the sections of the mire surface that have been milled represent a particular challenge in terms of restoration. The reinstatement of the Sphagnum layer or acrotelm typical of raised mire sites is an important restoration objective. In order for Sphagnum to re-colonise a cut over mire site the water table must remain in close proximity to the surface of the peat throughout the year. The absence of an acrotelm however contributes to seasonal water table fluctuation by decreasing surface storage and allowing increased evaporation from the surface .On cutover mire sites primary restoration efforts centre on raising the water table sufficiently to facilitate Sphagnum re-colonisation and growth with a view to restoring a functioning acrotelm. This study provides a critical appraisal of a restoration programme that aims to raise water levels on a cutover section of Wedholme Flow in Cumbria. The restoration programme was undertaken by Natural England who own and manage the site. Since acquiring the cut-over section of the site bunds and peat plugs have been installed to reduce drainage and raise the water table. Boreholes have been installed on site to monitor changes in water level during and after the restoration. The progress of the restoration programme is evaluated through examination of the water balance, available groundwater data and a review of contemporary literature. Recommendations for further restoration and monitoring are made.
Open Access
Finite element analysis of laminated glass
(Cranfield University, 2009-09) Watson, Chris; Walton, A.; Skordos, Alexandros A.
In the road and rail industries, annealed float glass is combined with a thin polymeric layer to form a 3-ply glass/PVB/glass structure known as laminated glass. Amongst other characteristics, the PVB acts to retain fractured glass fragments, thus minimising injury from flying glass shards. Previous attempts at predicting the behaviour of laminated glass during impact have proven difficult due to complex stress fields caused by the large differences in moduli. The following research made an attempt at modelling laminated glass using the Laminated Glass model of LS-DYNA (MAT_32). Experimental results, used for model validation, displayed a large amount of scatter that may have been due to differences in manufacturing conditions. Numerical prediction results showed the model to be highly sensitive to mesh refinement. The resultant data showed poor correlation with experimental results predicting a much softer response.
Open Access
House buyer perceptions on the value of water and grey water recycling systems
(Cranfield University, 2009-08) Horton, David; Jeffery, Paul
The population of the East of England is set to increase and climate change predictions suggest that the region will become drier; water resources will therefore come under increasing pressure. In order to meet future water demand and deliver a reliable supply in the years to come, Cambridge Water is assessing the feasibility of installing grey water recycling systems in future housing developments. Grey water is wastewater from showers, baths, and wash basins. Recycling this water is an innovative way to conserve water. Treated grey water is used principally for toilet flushing- which represents about a third of water use in a typical UK household- but also for watering gardens and washing cars. This study investigated house buyer perceptions on the value of water and grey water recycling systems. For this purpose 2000 customers were surveyed using a questionnaire. The aim was to inform Cambridge Water as a water supplier of how receptive their customers would be to receiving a secondary supply of treated grey water for non-potable use. All those sampled had moved into a newly built home in the past two years. Since investing in grey water recycling systems would have little or no financial benefit for the homeowner, the study focused on other potential benefits. The response rate for the survey was 22 per cent and the quantitative data was analysed using descriptive statistics. The results show that there was widespread support for the domestic use of grey water. The overwhelming majority of respondents would be willing to invest in grey water recycling systems because they are concerned about the environment, and to ensure a reliable supply at times of water scarcity. Many of those that objected stated that they would need further information before giving their consent.
Open Access
Impact of MIEX pre-treatment on floc strength and structure
(Cranfield University, 2009-09) Burton, Vincent; Jarvis, Peter
In drinking water treatment regulation standards for natural organic matter (NOM) are tightening owing the fact that NOM leads to formation of carcinogenic disinfection by-products which can be harmful for human health. To further remove NOM from water, advanced NOM removal processes are developed such as the magnetic ion exchange (MIEX) resin process. MIEX followed by coagulation has been shown to improve the dissolved organic carbon removal in comparison with coagulation alone. However knowledge is lacking about how the magnetic resin influences the floc structure which is of major importance for the efficiency of the downstream processes. The present thesis aimed to evaluate and understand the impacts of MIEX pre-treatment on floc properties. To meet these aims, a literature review was carried out in order to provide sufficient background on floc size, floc strength, re-growth potential and fractal dimension concepts. It showed that almost all of factors influencing these properties act on the floc structural properties via a modification of either the nature of the primary particles, or the conditions of coagulation process, or the hydrodynamic conditions of the surrounding water. De facto, these pre-cited properties are all linked together. It is especially recommended to interpret with care the floc strength concept. The pre-defined objective was to compare properties of flocs generated by coagulation alone and combined treatment (MIEX pre-treatment followed by coagulation). Coagulation steps were operated with three different coagulants - FeCl3, AlCl3, PACl - at optimum pH and dose conditions on jar test bench. A light scattering instrument measured floc size and fractal dimension during growth, breakage and regrowth periods. Additional fractal dimension measurements for ferric flocs were gathered by image analysis using a microscope. MIEX pre-treated flocs were larger but withstood less well increases in shear rate than conventional flocs. This reduced robustness to increases in shear rate was thought to be due to the initial larger size of the pre-treated flocs. Light scattering and image analysis gave different fractal dimension values for the same floc system. It is probably because they are applicable for different size ranges: light scattering for the small primary particles and image analysis for the overall flocs. Of more operational interest, image analysis results showed that MIEX pre-treated flocs were more compact. Combined treatment gave an overall improvement in floc structure quality, producing flocs with better filterability and settleability.
Open Access
Impact of NOM on flocs created in the drinking water process
(Cranfield University, 2008-09) Cairns, Peter Ryland; Jefferson, Bruce
Increased regulatory pressure to meet THM standards with the possible introduction of HAA regulations means that organic matter, the predominant DBP precursor needs to be removed effectively from site whilst coping with increased economic and environmental drivers for change. Organics are typically removed via coagulation / flocculation which can be optimised by operating in the correct zeta potential range (-10mV and +8mV) and the correct DOC:FE coagulant dose ratio (1:1). However, due to spatial and temporal changes in bulk NOM and its fractional character there are no standard operating conditions, consequently sites have to respond to changing conditions. Seasonal trends in DOC and THMFP levels were measured under optimised and current operational conditions. Results indicated that UV254 could be used to predict coagulant dose and zeta potential could be used to indicate optimum coagulation conditions for DBP precursor removal across 16 sites. Under optimised condition improved organics removal and floc properties was observed across all source waters however the degree to which this occurred depended on the source water. Understanding of the fractional make up is thus important to assess the potential for optimisation of the coagulation process. Providing the electrostatic forces are minimised, increasing the NOM content of the floc matrix will lead to an increase in floc strength. One of the implication of optimised coagulation conditions were that flocs could be created at lower retention time then quoted by best practice guidelines. As such a 66% decrease in flocculation energy could be achieved without any detrimental impact to floc quality or removal efficiency. One of the important findings is that due to the inherent difference in source waters, optimisation for a site can vary in terms of cost and clarified water quality, hence each site needs to be evaluated before schemes are carried out.
Open Access
Improve the energy efficiency of a full scale integated fixed film activated sludge (IFAS) process at Thames Water Oxford WWTW
(Cranfield University, 2009-09) Buñol i Tordera, Ramon; Jefferson, Bruce; Healey, Kieran; Barugh, Angela
The primary objective of integrated fixed film activated sludge (IFAS) is to remove dissolved pollutants from wastewater. This process allows an increased treatment capacity in comparison with conventional activated sludge. Thames Water has been operating a full scale IFAS biological process demonstration lane of 870 m 3 at the Oxford wastewater treatment works for over two years. The aim of this study was to evaluate the benefits of using an ammonia feed back control system as an alternative to a conventional set point dissolved oxygen control in order to improve energy efficiency in the aeration system. The main finding was that the adjustment of dissolved oxygen (DO) set points regulated by the feedback control system resulted in periods of excess or deficiency of DO in the wastewater with an total over aeration of 14.7 % and under aeration of 9.8 %. Investigation into the causes of the deviations found that the speed of the control equipment was unable to match the responsiveness of the control set point leading to periods where the air control valve was either too open or too closed. A linear equation was established to relate the influent wastewater flow with the time taken by the ammonia to be detected in the settled sewage stream in the IFAS process lane. Thus a feed forward control philosophy was suggested to control the aeration system, as opposed to the feed-back control system in order, to improve the target DO set point. Alongside this study, a comparison of the energy costs between IFAS with the ammonia feed-back control philosophy and a conventional activated sludge set point DO control system was completed. The analysis found negligible difference between the two processes. In addition when compared to the calculated design aeration requirements for set point DO control for the observed actual oxygen required (AOR) loadings, it was found that operating the IFAS system in NH4-N feed back control requires significantly less air. It can therefore be concluded that, with further research, the IFAS process can still be optimised to reduce aeration energy costs.
Open Access
An investigation into illegal discharge of sewage from boats in the broads
(Cranfield University, 2008-09) Hardwick, Susannah; Holman, Ian P.
In response to concerns expressed by the Environment Agency and Broads Authority, this project aimed to assess the risk of illegal sewage discharge from boats into the waterways of the Broads, East Anglia. The Broads are an internationally important wetland, consisting of marshes, fenland, rivers and shallow lakes. A popular area for boating, sewage discharge from boats could have deleterious impacts on the environment, health and public perception. Water was tested for evidence of faecal pollution at a mooring site at Thorpe Island, River Yare, identified as at risk from illegal sewage disposal from boats. Continuous monitoring of ammonia, ammonium and dissolved oxygen up and downstream of the moorings took place at half hourly intervals over six weeks. Thermotolerant coliforms, ammonia, phosphorous and dissolved oxygen were manually sampled at Thorpe Island and nearby Whitlingham sewage treatment works. Definitive evidence of pollution from boats was not found, either sewage was not illegally discharged during the study period, or methods were inadequate to identify the occurrence of faecal pollution with certainty. The distribution of sewage disposal facilities available for boats was also analysed. The navigable waterways of the Broads were categorised in terms of the risk of illegal sewage disposal due to distance from disposal facilities. The south eastern reaches of the River Bure and western reaches of the River Waveney were identified as being at most risk. Recommendations are made to identify areas of the Broads at risk from pollution due to factors other than distance from sewage disposal facilities. Any further water quality studies should be carried out in these areas and improvements to the methods are suggested. Future management should include raising awareness of boaters about issues surrounding sewage disposal and the consideration of the provision of either mobile or static sewage disposal facilities in areas where current provision is deemed inadequate.
Open Access
Investigation into the manipulation of the properties of Indium Tin Oxide (ITO) coatings
(Cranfield University, 2008) Atterbury, Clair; Nicholls, J. R.; Hatchett, Phil
This thesis investigates the manipulation of the properties of Indium Tin Oxide (ITO) coatings. This is carried out with a combination of Experimental and Theoretical work. The coating of ITO onto a glass substrate was both theoretically modelled and the practical work analysed to observe the effects. Observation of the effects on the output parameters when depositing a single layer of ITO via Electron beam evaporation onto a glass substrate multiple times with varying conditions was carried out. The amount of ITO required to produce optimum % transmission and the deposition conditions required to provide <20 7/▢ and <100 7/▢ were investigated. This study then considered the addition of a single layer of an additional coating both theoretically and practically to maximise the %T for the wavelength ranges under consideration. From this, the ideal refractive index for the additional coating to maximise the %T for the ranges was deduced. Progression was then made to consider multiple layers. Theoretical work carried out on the addition of extra layers and the deduction of the optimal refractive index implied that overall, Cryolite would produce the best average %T across the ranges considered. In addition to this, the results of ITO deposition via Evaporation and sputtering were examined to determine the difference the technique used has upon the coating produced.