Buses, the main form of public transport in many urban areas, are considered as an efficient and environmentally friendly transport mode because of their high passenger capacity. The concept of bus priority was originally proposed to protect buses from urban traffic congestion so that buses can be perceived as a faster mode than private cars. One such measure which is expanding in extent and sophistication is bus priority at traffic signals – or Bus Signal Priority (BSP) Strategies. The previous research on BSP has mostly focused on its effectiveness on improving bus efficiency and bus regularity/punctuality, as well as the impacts on general traffic. However the potential environmental impacts that could be caused by BSP have not been studied, particularly on emissions - despite this being an increasingly important criterion in transport assessments. For bus priority implementations this could be particularly important, if the small disbenefits to a large number of the nonpriority vehicles outweigh the benefits to buses. This lack of knowledge and potential concern has been the main motivation for this research. The thesis sets out a comprehensive review on the state-of-the-art BSP systems and evaluation approaches. It revealed that microscopic traffic simulation models are the most appropriate approach for this study with the ability to model different BSP strategies in various user-defined scenarios. The Aimsun model was selected after review and comparison. From the review on the measurement and modelling approaches for transport related emissions, instantaneous emission models were found to be able to estimate emission behaviour by relating emission rates to vehicle operation during a series of short time intervals (often one second) and for a small scale. This was required by this study as at junction areas emissions could be dominated by vehicle operational modes where the traditionally ‘average speed’ models were unable to accurately capture the emission variations. The dynamic and individual-oriented features of microsimulation models and instantaneous emission models enabled their integration at various spatial and temporal levels and at different levels of vehicle aggregation. After calibration and validation to some critical parameters in Aimsun, a signalised junction under VA control was set up, and two BSP strategies were modelled, - one including green extension and early green recall facilities and the other one including additional compensation and inhibition facilities. These strategies were applied to 18 typical scenarios, involving variables of ‘degree of saturation’, traffic flows and bus flows. The results illustrated the importance of strategy optimising in the more challenging conditions of junctions operating under high degrees of saturation and /or high bus flows. The worst-case scenario was in heavy traffic conditions with high bus flows and BSP on the minor road only, when emissions could increase by about 10%. Under a free flow condition implementing BSP on the main road is an environmentally friendly measure with emissions reductions of up to 6%.The thesis also describes a method to value emissions in monetary terms, so that operational and emissions impacts can be compared in common units. Application of this method indicated that the impact of emissions is much smaller than that for delay/journey time impacts, though some under-estimation in emissions valuation is suspected.

The research reports on the potential for CO2 pressurisation as a means of enhancing biogas production in the anaerobic digestion of co-settled sewage sludge, a technique reported in the commercial literature as showing great benefits. The possibility of using this technique to reduce the number of faecal indicator bacteria is also explored, as an alternative means of complying with the UK water industry's Safe Sludge Matrix. Initial research using pure cultures of both E. coli (a strain isolated from sewage sludge) and Salmonella enterica showed that the results from different methods for isolating, recovering, resuscitating and enumerating E. coli were comparable. Further testing using heat stressed and unstressed E. coli showed the advantages of resuscitation and the MPN technique with 2-stage incubation was therefore used in the experiments to maximise the recovery of damaged but viable cells. The results for pure cultures showed conclusively that under the conditions of time and pressure used CO2 pressurisation and rapid depressurisation could cause irreversible cell damage and loss of viability in both test strains. The effect was reproducible and a time-pressure relationship was established for the apparatus used. It was shown, however, that the sanitising effect was influenced by culture volume, probably as this affected mass transfer of CO2 and hence its penetration into the cells. This finding may limit the practical application of the approach and further work is needed to establish design parameters and develop reactor systems to overcome this issue. Even under the favourable conditions used, exposure times required for 6 log reduction were too long for commercial application. Optimisation of the pressurisation vessel design may improve this and should be a focus of any future investigations. Batch and semi-continuous anaerobic digestion tests with co-settled sewage sludge were carried out to ascertain the effect of pressurised CO2 treatment on biogas production. These showed conclusively that the treatment did not improve either biogas productivity or specific methane yield. Experimental work also showed that even treatment conditions which gave an 8 log reduction in E. coli in pure culture were ineffective in reducing the number of indigenous E. coli in the sludge, or of S. enterica when added to a sewage sludge matrix. These findings led to further investigation of the effects of the size of pressure vessel and sample used. The results showed that this was an important factor, but could not fully explain the lack of performance in comparison with pure culture. It was concluded that the sludge matrix itself must play a role in protecting the microbial consortia from the effects of pressurised CO2. The exact reasons for this were not discovered but may be due to the effect of dissolved compounds present in the sludge and/or the structure and nature of the sludge flocs themselves.

Contamination of aquatic environments via anthropogenic release of metals is an increasing global environmental concern. The greatest concerns exist within estuarine and harbour environments, where point and non-point metal sources are prevalent. Historically, monitoring programs were initially (and largely) based on chemical analyses; however, the identification of a number of shortcomings in this approach resulted in a shift towards the complementary use of biological monitoring (biomonitoring). The aim of this study is to investigate and compare the suitability of selected aquatic invertebrate taxa biomarker responses (by production of metallothionein- MT) for assessment of aquatic environmental conditions in three coastal estuaries in Southern England: Poole Harbour, the Fal estuary and the Solent. This was delivered through a critical review of the current status of metal contamination in biota, water and sediment within these estuaries; by investigation of the suitability of selected species’ metallothioneins to act as biomarkers by assessing their correlation with metal pollution; by assessment of the effectiveness of these organisms as bioindicators in biomonitoring studies; and though investigation of the potential use of MT concentrations in these species as biomarkers of metal exposure in monitoring programmes. Legislation has been established to facilitate the protection, and enhance the quality, of all water bodies, including coastal waters and estuaries to prevent their deterioration and to ensure they achieve ‘good’ ecological health; but examination of water and sediment samples showed that historical metal pollution has not been dispersed and still affects environmental quality. In Poole Harbour, metal contamination was detected in all environmental compartments. The enclosed nature of the harbour and its secondary embayments make it vulnerable to the effects of these metal sources which disperse extremely slowly due to restricted tidal exchange; and a significant part of the pollution load remains in coastal areas close to land based contamination sources. In Poole Harbour, water was polluted with As (ranged from 29.6 to 212.8 μg/l) and Hg (ranged from 0.368 μg/l to 11.06 μg/l) which are above the Environmental Quality Standard (EQS) set by the European Union dangerous substances directive (EUDSD). Sediment metals were mostly within “the possible effect range” at which adverse effects occasionally occur, according to the Canadian Sediment Quality Guidelines (CSQG). Although cockles (Cerastoderma edule) had higher tissue concentrations of Ni, Ag and Hg in areas close to pollution sources, and sponges (Haliclona oculata) had accumulated Cu and Zn with a very high magnitude, the absence of EQS for metals in living organisms’ tissues makes it difficult to specify whether the metal concentrations reached a dangerous level or not in these organisms. The results confirmed the presence of a marked metal pollution gradient in the Fal Estuary between the ‘clean’ sites in the north and east of the estuary and the ‘polluted’ sites in the west of the estuary which were historically polluted by water from mines. Moreover, the concentrations of metals in almost all of the contaminated sites in the Fal and Solent estuaries have not changed significantly over the past few decades. This study investigated the potential of MT as biomarker of metal pollution in the following wild species: two well-studied bioindicators- common cockles (C. edule) from Poole Harbour, and mussels (Mytilus edulis) from the Fal estuary and the Solent; and tested the following novel bioindicators: sponges (H. oculata) from Poole Harbour, ragworms (Hediste diversicolor) From the Fal estuary, and limpets (Patella vulgata) from the Solent. The spectrophotometric method was used to measure MT in these species as it has been reported to be a sensitive, time saving, and low-cost technique able to detect MT content in the tissues of aquatic organisms. The results showed that MT concentration in these estuarine wild invertebrates vary between sites; however, these variations were not exclusively associated with metal concentrations and that other environmental factors may explain some of the MTs variability. The many uncertainties surrounding MT in wild organisms indicate that it may have limited potential as a biomarker in estuarine environments. It is also apparent that the importance of biotic and abiotic factors at polluted sites may limit its application. In this study, transplanted mussels (M. edulis) and Manila clams (Tapes philippinarum) were used as active biomonitoring tools in Poole Harbour. It was found that under extreme conditions of metal pollution, the relationship between metal concentrations and MT deviates from linearity: a threshold appears to be reached beyond which the physiological capacity of organisms introduced to polluted areas is exceeded. In the above transplanted animals, MT induction increased to peak levels with increased metal concentration, and then declined with further increases in the concentration.

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The disposal of biosolids poses a major environmental and economic problem. Agricultural use is generally regarded as the best means of disposal. Although the impact on soil ecosystems remains uncertain. Biosolids can improve soil properties by supplying nutrients and increasing organic matter content but there is also a potentially negative impact arising from the introduction of heavy metal contaminants into soils. It is widely acknowledged that the bioavailable fraction, rather than total metal content, is indicative of plant metal uptake and toxicity. The bioavailable metal fraction in turn is dependent on soil properties. Therefore, the overall aim of this work was to determine the bio-geochemical factors that control the dynamics of trace element bioavailability in soils that have been subject to the disposal of sewage sludge for over 100 years. Three main investigations were undertaken. In order to determine the current metal composition of the site and identifying the geochemical factors that control the dynamics of metals bioavailability, thirty -eight fields, from a dedicated sewage sludge disposal site for over 100 years, were sampled for both soil (bulk and rhizosphere) and plant. Special attention was devoted to determining soil properties that govern metal partitioning between different metal pools (i.e. total, isotopically exchangeable, Ca(NO3)2-extractable and free ion activity). In order to identify the best estimate of plant uptake and toxic response, a pot experiment was carried out to compare the effects of Zn on plant growth in soils recently spiked with Zn and soils historically amended with biosolids to identify soil properties that best predict metal uptake and subsequent phytotoxicity. The effect of biosolids on soil microorganisms was assessed. Terminal restriction fragment length polymorphism, a fingerprint molecular technique, in combination with multivariate data analysis were used to relate soil microbial diversity and community structure to metal accumulation and bioavailability. High levels of contamination, exceeding the current limits for the use of biosolids in agriculture, were observed in the studied soils reflecting extensive long-term biosolid application. Enrichment factors in relation to background levels in the area were greater than 5 and followed the trend Cd>Cu>Zn>Pb>Ni. Copper and Cd exhibited extremely high enrichment levels, up to 106 and 151 respectively. Except for Pb, the isotopically exchangeable pool of the studied metals (E-value) was mainly controlled by the total metal content in soil, accounting for more than 90% of the variation in E-values. Lead lability was primarily controlled by the total P, LOI and Fe oxides. Metal labilities expressed as % of total metal content were < 40% for the five studied elements following decreasing order of Cu > Cd > Zn ≈ Ni > Pb. Apart from Pb, all the bioavailability estimates (total, E-values, Ca(NO3)2-extractable and free ion activity) correlated strongly with metal concentration in plant, accounting for more than 70% of the variation in plant concentrations. Ca(NO3)2-extractable provided the best estimate out of the four measures of bioavailability, accounting for 87, 77, 87 and 83% of the variation in plant concentration of Ni, Cu, Zn and Cd respectively. The results of the pot trial showed that 67-90% of the added Zn remained isotopically exchangeable after 3 months of Zn addition, suggesting that rapid adsorption processes take place, followed by a slow aging process that cannot be detected over the period of the experiment (3 months). The speciation of soil solution showed that Zn was present mainly (80% on average) as free ion indicating the low affinity of this metal to complexation by dissolved organic matter. An antagonistic relationship was observed between Zn and Cd suggesting that greater Zn availability suppressed Cd uptake by plant. Although Zn addition increased Cd concentration in the soil solution, Cd transfer factor was simultaneously inversely correlated with Zn concentration in soil solution. The free ion activity model (FIAM), based on the biotic ligand model (BLM), accounted for 94% of the variation Zn concentration in plant. Cadmium appeared to play an important role in competing with Zn for uptake. A simple regression model utilising soil total Zn, soil organic matter and soil pH accounted for 88% of the variation in plant uptake. This indicates the possibility of using soil properties that are measured routinely as input for prediction of plant uptake. The results of the Zn phytotoxicity test indicated that the intensity of the exposure (i.e. free ion activity) was the key quantity in the context of predicting plant toxic response, describing 80% of the variation in the response of barley growth to Zn toxicity. Only labile Zn from the quantity based extraction was able to describe the toxic response explaining only 46% of the variation. The study of the effect of biosolids on soil microorganisms showed that soil total Zn concentration could be adopted as a good indicator of the overall (historical) biosolids loading. A biosolids loading, equivalent to 700 – 1000 mg kg-1 Zn appeared to be optimal for maximum bacterial and fungal diversity. This markedly exceeds the maximum soil Zn concentration of 300 mg kg-1permitted under the current UK Sludge (use in agriculture) Regulations. Redundancy analysis (RDA) suggested that the soil microbial communities had been altered in response to the accumulation of trace metals, especially Zn, Cd, and Cu. Based on the findings of this thesis, it can be concluded that (i) the estimation of metal speciation, both in the solution and solid phase is a key factor in determining the bioavailability and thus, has greater chemical and biological significance than soil total metal content; (ii) the maximum beneficial effect of biosolids on soil microbial diversity occurred at a metal (Zn) concentration well in excess of current regulations governing application of biosolids to agricultural land. This indicates that soil microbial diversity is unlikely to be determining factor for regulatory limits for biosolids disposal to agricultural lands.

Natural reedbed habitat in the UK has suffered severe declines in the last few centuries. With only 5,000 ha remaining and much of what remains is highly fragmented and degraded. The loss and fragmentation of reedbed habitat in the UK has had a profound effect on the species associated with it. Constructed reedbeds are artificial wetlands dominated by Phragmites australis designed to treat wastewater. They have been widespread in the UK because they are perceived to be a green solution, but their conservation value has never been assessed. This project aims to determine how they contribute to biodiversity. This study surveyed 24 sites, 12 constructed sites paired to 12 natural sites, for small mammals, moths and stem-dwelling invertebrates. Results show that there is no difference between constructed and natural sites. The indication is that constructed reedbeds, despite their small size, young age and contamination, are just as diverse as natural reedbeds. The implications of this for reedbed and wetland conservation are potentially substantial. There are over 1,000 constructed reedbeds in the UK that are just as diverse as their natural equivalents, which could provide connectivity across unsuitable agricultural and urban landscapes.

This thesis describes an investigation into the phenomenon of air entrainment in vertical dropshafts conveying water from a high level to a lower level. The study initially commenced with hydraulic tests on scale models of a vortex-entry dropshaft arrangement. This subsequently expanded into a more detailed analysis of the mechanisms involved in the air entrainment, rejection and transport processes evident in the early stages of the work. An attempt has been made to define the criteria controlling these three modes of operation in air/ water systems. The physical process of initial entrapment by the plunging water film was researched extensively. The inability to accurately reproduce the bubble sizes in scale models conclusively shows that this aspect is fundamental to the understanding of the problem. A dimensional analysis of the parameters controlling the rate of entrainment in the system was undertaken in the investigations. A number of dimensionless groups were obtained to describe the relationships between the parameters involved in the process. This enables the rate of air entrainment to be predicted in any.system of dropshafts under certain flow and geometrical conditions. The downward passage of air bubbles in water (just one mode of operation in two-phase flow systems) was investigated to establish the air transport capabilities of various flows and hence the air rejection process. An empirical relationship was derived which describes the air void ratio at various discharges and hence enables many aspects of the transport of air bubbles to be studied. A series of values defining the limits of operation of the phases invovled in air entrainment were also identified, e.g. onset of air entrapment and air transport.

There is a growing concern that current levels of economic activity have outgrown the physical limits of the planet. In the face of global constraints, humanity continues to deplete nature, through resource harvesting and waste generation, faster than nature can regenerate itself. The UN World Commission on Environment and Development (WCED) introduced the idea of sustainable development in 1987, with the release of Our Common Future. Sustainable development has since become a powerful and controversial theme, creating seemingly impossible goals for policy makers. Sustainable indicators can be a key mechanism for encouraging progress in the right direction by providing a measuring tool that gives a clearer understanding as to whether sustainability is being achieved. The ecological footprint has emerged as an innovative technique to measure the ecological dimension of sustainability. The research tests the ecological footprint as a tool for guiding humanity towards sustainability. The research establishes whether or not the ecological footprint provides an effective accounting framework for the biophysical services that a given society requires from nature. With Guernsey as the case study, the research investigates whether or not the ecological footprint is a comprehensive tool for local policy decision-making. Considering the methodology of the ecological footprint, its use for time series analysis and the development of scenarios does this. The ecological footprint is also tested for its ability to act as a tool to communicate the ideas of sustainability. In conclusion, while containing some limitations, the ecological footprint is a tool that can facilitate the comparison of policy choices society inevitably must face. At the local level, the ecological footprint is a valuable part of the sustainable indicator tool kit. The use of the ecological footprint as a communication tool for sustainable development is invaluable. It is an indicator that can be understood by the general public and one that links individual lifestyle choices to global environmental problems. The ecological footprint is only an empirical tool and in itself cannot change anything. It is a first step in a process of change and the political will and desire to change must be the driving force. Its great advantage over other sustainability indicators is that it is holistic and makes connections between different activities and impacts. However, the ecological footprint is based on assumptions as the ratios/equations calculated by others. In conclusion, the ecological footprint demonstrates that intelligent rationalisation of means and prudent moderation of ends is the only solution. By providing common ground, the ecological footprint builds bridges between different worldviews and amplifies the resonance between all disciplines working on sustainability.

The inherent nature of surfactants to aggregate at surfaces makes measurement of log P (octanoll water partition coefficient) for these substances extremely difficult. It is possible, however, to calculate a log P descriptor based on the method described by Hansch and Leo (1979). Work presented in this thesis describes the study of the acute toxicity of sulphonated esters (FAES) of general formula R-CH(S03"Na +)-C02-R' to Daphnia magna. Due to structural similarities of this class of anionic surfactant to linear alkylbenzene sulphonate (LAS), it was considered that the log P based QSAR originally developed to describe the toxicity of LAS to D. magna (Roberts, 1989) also would be a good predictor of the acute toxicity for FAES substances. Results of the toxicity studies showed that FAES substances were less toxic than predicted. However, when plotted against log P' Calculated using the conventional fragment approach of Hansch and Leo with the addition of a position dependent branching factor (PDBF) to account for water sharing between hydrocarbon chains, the regression slope was para"el to but distinct from that of LAS. This indicated that either FAES substances were not acting as by the same mode of action as LAS or that modification of the log P calculation was required. Further studies of the toxicity of binary mixtures of FAES with known polar and non-polar narcotics, established that FAES exhibited concentration addition with LAS and phenol. This indicated that they behaved with a similar mode of action and it would be expected that LAS and FAES would share the same QSAR. The difference of the regression slopes of FAES and LAS observed? earlier, therefore, suggested the requirement of a modification to the original log P calculation. The modified proximity factor developed in this thesis considers the effects of relative size of proximal polar fragments on log P.? Spherical hydration sheaths surrounding each fragment were assumed and 'overlapping volumes calculated for fragments at different carbon separation. When incorporated into the log P calculation, the new log P values now allow toxicity values for LAS and F AES substances to be incorporated into the same QSAR.

Made available in DSpace on 2014-06-11T19:29:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-06Bitstream added on 2014-06-13T20:59:41Z : No. of bitstreams: 1 avelino_mcgs_me_bauru.pdf: 1310267 bytes, checksum: 3759dbcf2bb00c77b6d84614fa3d81fd (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Esta dissertação de mestrado consistiu em elaborar e construir uma Estação de Tratamento de Esgoto (ETE) que utilizasse o sistema de Alagados Construídos (wetlands) para tratar o esgoto gerado no Departamento de Educação Física e da Moradia Estudantil, ambos ligados a Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP de Bauru. Para isso foi criado um sistema híbrido de fluxo subsuperficial horizontal seguido por outro de fluxo vertical, com recirculação. O projeto foi desenvolvido no campo da universidade para atender 91 habitantes equivalentes. Nesse trabalho, foram explorados as etapas construtivas da ETE e realizado análises físico-químicos e biológicos dos alagados construídos de fluxo vertical na fase de maturação do sistema. A elaboração deste estudo é uma ferramenta importante para o desenvolvimento do sistema de alagados construídos no Brasil, uma vez que, possibilita o conhecimento das técnicas de construção, manutenção e gastos para implantação de um sistema desse tipo / The realization of this research project is to develop and build a sewage treatment plant using the system of Constructed Wetlands to treat sewage generated in the Department of Physical Education and Student Housing, both linked to Universidade Estadual Paulista Julio de Mesquita Filho - UNESP in Bauru. For it was created a hybrid system of horizontal subsurface flow followed by another vertical flow, with recirculation. The project was developed at the university campus to meet 91 equivalent inhabitants. In this work were explored constructive steps ETE and testing of physico-chemical and biological of vertical flow constructed wetlands in the maturation phase of the system. The preparation of this study is an important tool for the development of constructed wetlands system in Brazil, since it enables the knowledge of construction techniques, maintenance and expenses fopr deploying such a system