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Item Open Access Biodegradability of organic matter associated with sewer sediments during first flush.(Elsevier, 2009-04-01) Sakrabani, Ruben; Vollertsen, Jes; Ashley, Richard M.; Hvitved-Jacobsen, ThorkildThe high pollution load in wastewater at the beginning of a rain event is commonly known to originate from the erosion of sewer sediments due to the increased flow rate under storm weather conditions. It is essential to characterize the biodegradability of organic matter during a storm event in order to quantify the effect it can have further downstream to the receiving water via discharges from Combined Sewer Overflow (CSO). The approach is to characterize the pollutograph during first flush. The pollutograph shows the variation in COD and TSS during a first flush event. These parameters measure the quantity of organic matter present. However these parameters do not indicate detailed information on the biodegradability of the organic matter. Such detailed knowledge can be obtained by dividing the total COD into fractions with different microbial properties. To do so oxygen uptake rate (OUR) measurements on batches of wastewater have shown itself to be a versatile technique. Together with a conceptual understanding of the microbial transformation taking place, OUR measurements lead to the desired fractionation of the COD. OUR results indicated that the highest biodegradability is associated with the initial part of a storm event. The information on physical and biological processes in the sewer can be used to better manage sediment in sewers which can otherwise result in depletion of dissolved oxygen in receiving waters via discharges from CSOs.Item Open Access Biomass effects on oxygen transfer in membrane bioreactors.(Elsevier, 2007-03) Germain, Eve; Nelles, F.; Drews, A.; Pearce, P.; Kraume, M.; Reid, E.; Judd, Simon J.; Stephenson, TomTen biomass samples from both municipal and industrial pilot and full scale submerged membrane bioreactors (MBRs) with mixed liquor suspended solids concentrations (MLSS) ranging from 7.2 to 30.2 g L−1 were studied at six air-flow rates (0.7, 1.3, 2.3, 3, 4.4 and 6 m3 m−3 h−1). Statistical analyses were applied to identify the relative impacts of the various bulk biomass characteristics on oxygen transfer. Of the biomass characteristics studied, only solids concentration (correlated with viscosity), the carbohydrate fraction of the EPS (EPSc) and the chemical oxygen demand (COD) concentration of the SMP (SMPCOD) were found to affect the oxygen transfer parameters kLa20 (the oxygen transfer coefficient) and α-factor. The relative influence on kLa20 was MLSS>aeration>EPSc>SMPCOD and on α-factor was MLSS>SMPCOD>EPSc>aeration. Both kLa20 and α-factor increased with increasing aeration and EPSc and decreased with increasing MLSS and SMPCOD. MLSS was found to be the main parameter controlling the oxygen transfer.Item Open Access Bioremediation of leachate from a green waste composting facility using waste-derived filter media(Elsevier, 2008-11) Tyrrel, Sean F.; Seymour, I.; Harris, Jim A.The evaluation of two waste-derived materials used to treat compost leachate by biofiltration is described in this paper. Nine biofilters were constructed using 240 l, high density polyethylene containers. Three containers were filled without compaction with 200 l of each of three types of filter media. Waste-derived filter media (compost and oversize) were compared to a mineral control (granite chips). The filters were fed with compost leachate from a typical green waste composting facility at hydraulic loading rates ranging from 0.05 m3/m3/day to 0.5 m3/m3/day over a period of twelve months. The oversize medium emerged as the most effective demonstrating characteristics of consistency of effluent quality and resilience to stress. The oversize medium produced an effluent of <10 mg/l ammoniacal nitrogen on >95% of sampling occasions. The organic component of compost leachate was dominated by compounds that proved to be recalcitrant to biodegradation. The solids content of the treated effluent remained too high to be acceptable for direct discharge to a watercourse without further treatment and if discharge to a watercourse is to be considered, a polishing stage (e.g., reed bed) able to remove solids and dampen occasional peaks of ammoniacal nitrogen should be employed.Item Open Access Comparative mesocosm study of biostimulation efficiency in two different oil-amended sub-antarctic soils(Springer, 2008-08) Delille, Daniel; Coulon, FredericBiological treatment has become increasingly popular as a remediation method for soils and groundwater contaminated with petroleum hydrocarbon, chlorinated solvents, and pesticides. Bioremediation has been considered for application in cold regions such as Arctic and sub-Arctic climates and Antarctica. Studies to date suggest that indigenous microbes suitable for bioremediation exist in soils in these regions. This paper reports on two case studies at the sub-Antarctic Kerguelen Island, in which indigenous bacteria were found that were capable of mineralizing petroleum hydrocarbons in soil contaminated with crude oil and diesel fuel. All results demonstrate a serious influence of the soil properties on the biostimulation efficiency. Both temperature elevation and fertilizer addition have a more significant impact on the microbial assemblages in the mineral soil than in the organic one. Analysis of the hydrocarbons remaining at the end of the experiments confirmed the bacterial observations. Optimum temperature seems to be around 10°C in organic soil while it was higher in mineral soil. The benefit of adding nutrient was much stronger in mineral than in the organic soil. Overall, this study suggests on the basis of microbiological and physicochemical parameters, that biostimulation treatments were driven by soil properties and that ex-situ bioremediation for treatment of cold contaminated soils will allow greater control over soil temperature, a limiting factor in cold climates.Item Open Access A decision support tool based on QFD and FMEA for the selection of manufacturing automation technologies(Elsevier, 2008-08) Almannai, B.; Greenough, Richard M.; Kay, John M.With the advent of the new challenge to design a more lean and responsive computer-integrated manufacturing system, firms have been striving to achieve a coherent interaction between technology, organisation, and people to meet this challenge. This paper describes an integrated approach developed for supporting management in addressing technology, organisation, and people at the earliest stages of manufacturing automation decision-making. The approach uses both the quality function deployment (QFD) technique and the failure mode and effects analysis (FMEA) technique. The principal concepts of both applications are merged together to form a decision tool; QFD in its ability to identify the most suitable manufacturing automation alternative and FMEA in its ability to identify the associated risk with that option to be addressed in the manufacturing system design and implementation phases. In addition, this paper presents the results of a practical evaluation conducted in industry.Item Open Access A decision support tool to facilitate the design of cellular manufacturing layouts(Elsevier, 2007-05) Vitanov, Val; Tjahjono, Benny; Marghalany, I.This paper presents a decision support tool that can be used by practitioners and industrialists to solve practical cell formation problems. The tool is based on a cell formation algorithm that employs a set of heuristic rules to obtain a quasi-optimal solution from both component routing information and other significant production data. The algorithm has been tested on a number of data sets obtained from the literature. The test results have demonstrated that in many cases the algorithm has produced an exceptional performance in terms of the grouping efficiency, grouping efficacy and quality index measures. The algorithm, to an extent, overcomes common problems in existing cell formation methods such as in dealing with ill-structured matrices and achieving rational cell sizes.Item Open Access Development of a Process Based Data Driven Engineering Design Knowledge Reuse System.(CAD Solutions (USA), 2006) Baxter, David; Gao, James X.This paper will describe the development of the web enabled version of a process based engineering design knowledge reuse system. The rationale for using the design process as a central element of knowledge management will be discussed. The system structure will be described. Evaluation of the prototype showed the most valuable attributes of system. Mapping the design process helped to create the product data model. Workshops were used to validate the system. A small number of product parameters are required for developing the product concept in the early stages. The research showed the importance of multi view validation and iteration in system development. It also showed the importance of graphics in design support. Key issues include: the importance of process capture, data model validation, the use of graphics in the interface, system design and system assessment.Item Open Access Failure prediction for advanced crashworthiness of transportation vehicles.(Elsevier, 2004-08) Pickett, Anthony K.; Pyttel, Thomas; Payen, Fabrice; Lauro, Franck; Petrinic, Nikica; Werner, Heinz; Christlein, JensDuring the past two decades explicit finite element crashworthiness codes have become an indispensable tool for the design of crash and passenger safety systems. These codes have proven remarkably reliable for the prediction of ductile metal structures that deform plastically; however, they are not reliable for joining systems and materials such as high strength steels, plastics and low ductility lightweight materials all of which are liable to fracture during the crash event. In order to improve crash failure prediction of materials and joining systems the CEC has recently funded a 3 year European research project dedicated to this topic. Specifically the project concerned aluminium, magnesium, high strength steels, plastics and two primary joining techniques; namely spotwelds and weldlines. Numerous new developments were undertaken including improved failure laws, adaptive meshing and element splitting to treat crack propagation. In the case of sheet stamping, investigations have also tried to account for process history effects and the metallurgical changes that occur during manufacture. This project has recently finished and this paper presents some of the key research results of the work concerning materials failure modelling.Item Open Access Impact of Zr/Ti ratio in the PZT on the photoreduction of silver nanoparticles.(Elsevier, 2009-06-03) Tiwari, Divya; Dunn, Steve; Zhang, QiSilver nanoparticle deposition from an aqueous solution of silver nitrate onto the surface of PZT thin films of stoichiometric compositions PbZr0.3Ti0.7O3 and PbZr0.52Ti0.48O3 has been investigated. The impact of Zr/Ti ratio on the photochemical properties of PZT is shown by the preferential growth of silver nanoparticles onto the surface. Photoreduction of silver occurs on both c+ and c− domains on PbZr0.52Ti0.48O3 whereas it occurs only on c+ domains on a PbZr0.3Ti0.7O3 surface. The difference in deposition pattern is attributed to difference in magnitude of spontaneous polarization, effective hole concentration and band gap of the two samples which impacts shape and width of space charge layer in the two samples resulting in a change in band bending at the surface.Item Open Access Influence of ferroelectricity on the photoelectric effect of LiNbO3.(American Institute of Physics, 2008-09) Dunn, Steve; Tiwari, DivyaA comparison between the influence of domain dependent photochemical and photoelectric cation reduction on the surface of LiNbO3 is presented. The reduction of the photoelectric threshold for LiNbO3 due to the polar nature of the crystal allows high energy UV irradiation to produce free electrons that can participate in photochemical reduction of silver nitrate on the surface. This is in addition to the previously understood phenomenon of domain directed photophysics, where influences on space charge layer due to the internal dipole of a ferroelectric determine the carrier at the surface. We show that the interaction of photoelectric and domain dependent influences can be observed in LiNbO3 due to the low electron affinity (ca 2eV) and large band bending (0.8eV).Item Open Access Is it possible to increase the sustainability of arable and ruminant agriculture by reducing inputs?(Elsevier, 2009-02) Glendining, M. J.; Dailey, A. G.; Williams, Adrian G.; van Evert, F. K.; Goulding, K. W. T.; Whitmore, A. P.Until recently, agricultural production was optimised almost exclusively for profit but now farming is under pressure to meet environmental targets. A method is presented and applied for optimising the sustainability of agricultural production systems in terms of both economics and the environment. Components of the agricultural production chain are analysed using environmental life-cycle assessment (LCA) and a financial value attributed to the resources consumed and burden imposed on the environment by agriculture, as well as to the products. The sum of the outputs is weighed against the inputs and the system considered sustainable if the value of the outputs exceeds those of the inputs. If this ratio is plotted against the sum of inputs for all levels of input, a diminishing returns curve should result and the optimum level of sustainability is located at the maximum of the curve. Data were taken from standard economic almanacs and from published LCA reports on the extent of consumption and environmental burdens resulting from farming in the UK. Land-use is valued using the concept of ecosystem services. Our analysis suggests that agricultural systems are sustainable at rates of production close to current levels practiced in the UK. Extensification of farming, which is thought to favour non-food ecosystem services, requires more land to produce the same amount of food. The loss of ecosystem services hitherto provided by natural land brought into production is greater than that which can be provided by land now under extensive farming. This loss of ecosystem service is large in comparison to the benefit of a reduction in emission of nutrients and pesticides. However, food production is essential, so the coupling of subsidies that represent a relatively large component of the economic output in EU farming, with measures to reduce pollution are well-aimed. Measures to ensure that as little extra land is brought into production as possible or that marginal land is allowed to revert to nature would seem to be equally well-aimed, even if this required more intensive use of productive areas. We conclude that current arable farming in the EU is sustainable with either realistic prices for products or some degree of subsidy and that productivity per unit area of land and greenhouse gas emission (subsuming primary energy consumption) are the most important pressures on the sustainability of farming.Item Open Access Measuring Floc Structural Characteristics(Springer, 2005-05) Jarvis, Peter; Jefferson, Bruce; Parsons, Simon A.A review is presented of a range of techniques for the structural characterisation of flocs. Flocs may be considered as highly porous aggregates composed of smaller primary particles. The irregular size and shape of flocs makes them difficult to measure and quantify. A range of different equivalent diameters are often used to define the floc size and allow comparison with other floc systems. The application of a range of floc sizing methods has been described. Microscopy is time consuming, requiring large sample size and considerable preparation but gives good information on floc shape and form. Light scattering and transmitted light techniques have been used to good effect to measure floc size on-line whilst individual particle sensors have limited applicability to measuring floc size. Fractal dimension can be measured using one of three major techniques: light scattering, settling and two dimensional (2D) image analysis. Light scattering is ideally suited for small, open flocs of low refractive index whilst settling may be applied to most floc systems of low porosity. 2D image analysis requires flocs to have good contrast between the solid in the floc and the background.Item Open Access Mechanical sludge disintegration for the production of carbon source for biological nutrient removal.(Elsevier, 2007-04) Kampas, Pantelis; Parsons, Simon A.; Pearce, P.; Ledoux, S.; Vale, P.; Churchley, J.; Cartmell, EliseThe primary driver for a successful biological nutrient removal is the availability of suitable carbon source, mainly in the form of volatile fatty acids (VFA). Several methods have been examined to increase the amount of VFAs in wastewater. This study investigates the mechanism of mechanical disintegration of thickened surplus activated sludge by a deflaker technology for the production of organic matter. This equipment was able to increase the soluble carbon in terms of VFA and soluble chemical oxygen demand (SCOD) with the maximum concentration to be around 850 and 6530 mg l−1, for VFA and SCOD, respectively. The particle size was reduced from 65.5 to 9.3 μm after 15 min of disintegration with the simultaneous release of proteins (1550 mg l−1) and carbohydrates (307 mg l−1) indicating floc disruption and breakage. High performance size exclusion chromatography investigated the disintegrated sludge and confirmed that the deflaker was able to destroy the flocs releasing polymeric substances that are typically found outside of cells. When long disintegration times were applied (10 min or 9000 kJ kg−1 TS of specific energy) smaller molecular size materials were released to the liquid phase, which are considered to be found inside the cells indicating cell lysis.Item Open Access A Mechanism for the Erosion of EB PVD TBCS(Trans Tech Publications, Switzerland., 2000-07-10) Wellman, R. G.; Nicholls, John R.Since the introduction of electron beam (EB) physical vapour deposition (PVD) TBCs and their application to moving components in the hot gas stream, erosion has become a prime concern. This project has been involved in determining the erosion mechanism of EB PVD TBCs, in order to develop a computational erosion model. The unique columnar microstructure of the EB PVD TBCs precludes the use of the classical brittle erosion mechanisms. This meant that a thorough investigation into the erosion mechanism of the coatings was necessary before it would be possible to develop a model to predict material wastage.Item Open Access Mechanisms leading to post-supply water quality deterioration in rural Honduran communities(Elsevier, 2005-05-13) Trevett, Andrew F.; Carter, Richard C.; Tyrrel, Sean F.Drinking water can become contaminated following its collection from communal sources such as wells and tap stands, as well as during its storage in the home. However, the mechanisms leading to contamination between the points of supply and consumption have not been well documented. This study carried out field-based experiments in three rural Honduran communities to investigate the potential for contamination through hand contact, method used to draw water, and dirty collection containers. The possibility of bacterial growth occurring in stored water was also considered. Hand–water contact was observed frequently during the collection and drawing of drinking water. Faecal contamination was present on 44% of women's fingertips tested during normal household activities, and this faecal material was easily transferred to water. An immediate deterioration in water quality was observed on filling collection containers. Faecal material was detected on cups and beakers used for drawing stored drinking water. Evidence was produced indicating that thermotolerant coliforms remain attached to the inner surface of clay storage containers after rinsing. Drinking-water quality deteriorates during collection and storage as a result of multiple factors linked to hygiene practices and circumstances. However, hands have the greatest potential to introduce contamination because of the constant risk of contact during household water management.Item Open Access Morphological and physico-chemical properties of British aquatic habitats potentially exposed to pesticides.(Elsevier, 2006-04) Brown, Colin D.; Turner, Nigel; Hollis, John; Bellamy, Patricia H.; Biggs, Jeremy; Williams, Penny; Arnold, Dave; Pepper, Tim; Maund, SteveApproaches to describe the exposure of non-target aquatic organisms to agricultural pesticides can be limited by insufficient knowledge of the environmental conditions where the compounds are used. This study analysed information from national and regional datasets gathered in the UK describing the morphological and physico-chemical properties of rivers, streams, ponds and ditches. An aggregation approach was adopted, whereby the landscape was divided into 12 hydrogeological classes for agricultural areas and a 13th class that comprised non-agricultural land. The data describe major differences in the abundance, dimensions and chemistry of waterbodies in the different landscapes. There is almost an order of magnitude difference in the total input of pesticide per unit area between the different landscapes. Ditches are shown to be most proximate to arable land, streams and rivers intermediate and ponds the least proximate. Results of the study have implications for the development of standard scenarios for use in protective screening steps within the risk assessment. Data can be used to produce more realistic estimates of the exposure of aquatic systems to pesticides and to examine how that exposure varies across the landscape.Item Open Access Operating strategies for variable-flow sequencing batch reactors.(Blackwell Publishing, 2007-03) Bungay, S.; Humphries, M.; Stephenson, TomSequencing batch reactors (SBRs) are variable-volume, non-steady-state, suspended-growth biological wastewater treatment reactors. The treatment process is characterised by a repeated treatment cycle consisting of a series of sequential process phases: fill, react, settle, decant and idle. The design and operation of an SBR must take into account (1) the biological process requirement for treating influent wastewater and (2) the hydraulic requirement to enable throughput of the water through the reactor without compromising on the quality of biological treatment. During routine operation, the priority between the process and hydraulic consideration can change depending on the influent flow rate and its rate of change. The importance of the interaction between these considerations will vary depending on the fill strategy and the cycle time control strategy. Where flow-proportional cycle times are utilised to optimise the treatment process, the operating strategy must be capable of accurately adjusting the intercycle phase times to prevent loss of biological treatment or volumetric capacity. This paper considers various operating strategies and describes the specific strategy used at the SBR at Avonmouth wastewater treatment works.Item Open Access Optimisation of business process designs: An algorithmic approach with multiple objectives.(Elsevier, 2007-09) Vergidis, K.; Tiwari, Ashutosh; Majeed, Basim; Roy, RajkumarMost of the current attempts for business process optimisation are manual without involving any formal automated methodology. This paper proposes a framework for multi-objective optimisation of business process designs. The framework uses a generic business process model that is formally defined and specifies process cost and duration as objective functions. The business process model is programmed and incorporated into a software platform where a selection of multi-objective optimisation algorithms is applied to a range of test designs including a real example. The test business process designs are of varying complexity and are optimised with three popular optimisation techniques (Non-Dominated Sorting Genetic Algorithm II (NSGA2), Strength Pareto Evolutionary Algorithm II (SPEA2) and Multi-Objective Particle Swarm Optimisation (MOPSO) algorithms). The results indicate that although business process optimisation is a highly constrained problem with fragmented search space; multi-objective optimisation algorithms such as NSGA2 and SPEA2 produce a satisfactory number of alternative optimised business process designs. However, the performance of the optimisation algorithms drops sharply as the complexity of the process designs increases. This paper also discusses the directions for future research in this particular area.Item Open Access Return merchandize authorization stakeholders and customer requirements management—high-technology products.(Taylor and Francis, 2007-04) Chen, Y. C. K.; Sackett, Peter J.Asian based enterprises providing high technology mass market products to the developed countries are competing in a marketplace where customers are demanding the highest standards of service. To develop successful product service capabilities - including technological change, product differentiation, timing, contingency planning, marketing and financial considerations, these companies need to fully identify the market stakeholders and quantitatively prioritise their requirements. This paper describes a methodology to identify the different types of stakeholders in the high technology product market and manage their requirements. The methodology provides a basis for sustainable competition that exploits global market opportunities and enables ultra-fast-to-market products to be supported at a level that meets customer demands. The case study application is in mass market electronic products; the potential application is wide.Item Open Access Spatio-temporal variability of some metal concentrations in the soil of eastern England, and implications for soil monitoring.(Elsevier, 2006-08) Lark, R. Murray; Bellamy, Patricia H.; Rawlins, B. G.Previous workers have proposed the use of multivariate geostatistics for the problem of estimating temporal change in soil properties for soil monitoring, but this has yet to be evaluated. We present a case study of this approach from the Humber–Trent region in North East England. We extracted data from two sources on cobalt, nickel and vanadium concentrations in the topsoil on two dates. Auto-variograms were estimated for each metal on each date, and pseudo cross-variograms for each metal on the two dates. It was shown that robust estimators of the auto and pseudo cross-variograms were needed for the analysis of these data. A linear model of coregionalization was then fitted to describe the spatio-temporal variability of each metal.