Les mousses liquides sont des dispersions des bulles dans l'eau et elles sont largement utilisées dans un grand nombre de procédés technologiques et d’applications commerciales. Dans ma thèse, je me concentre sur les différents problèmes concernant les propriétés des mousses aqueuses et en particulier les écoulements gravitationnels dans les mousses.Les mousses contiennent une grande quantité d'interfaces couvertes par des molécules amphiphiles, et l'échange des tensioactifs entre l'interface et la phase volumique joue un rôle important pour la génération et la stabilité des mousses. Donc, mon premier projet a été d'étudier la dynamique d'adsorption de systèmes modèles aux interfaces air/eau. Les résultats obtenus nous ont aidés à comprendre comment l'adsorption lente des tensioactifs lors de la génération de la mousse peut influencer la mobilité des interfaces et changer le drainage de la mousse. Pour étudier les différents aspects de la physique de la mousse à l'échelle des bulles, des mousses pseudo-bidimensionnelles (des monocouches des bulles serrées entre deux plaques) sont largement utilisées. Dans ma thèse un modèle pour décrire la géométrie d'une mousse pseudo-bidimensionnelle a été introduit, cette description a été utilisée pour modéliser les conductivités électriques et hydrauliques de ces mousses. Dans certaines applications (par exemple, dans les industries du papier et de la peinture) la formation de la mousse peut causer de graves problèmes et des agents antimoussants appropriés sont utilisés. Dans ma thèse l'influence de la gravité sur l'efficacité antimoussante des gouttes d'huile de silicone a été étudiée expérimentalement en utilisant des vols paraboliques. Les résultats montrent que les particules antimoussantes ont besoin de la gravité pour être transportées d'une manière efficace, et la microgravité rend les antimousses très efficaces pratiquement inutiles. Etant initialement motivé par le transport des particules dans les mousses, j'ai également examiné la sédimentation des particules solides dans les capillaires de verre verticaux et inclinés. / Liquid foams are dispersions of bubbles in water and they are widely used in a large number of technical processes and commercial applications. In the present thesis I focus on different problems concerning properties of aqueous foams and especially gravity-driven flows in foams. Foams contain a large quantity of interfaces covered by surfactant molecules and the surfactant exchange between bulk and interface plays a crucial role for foam generation and stability. So my first project was to study the adsorption dynamics of model surfactant systems at air/water interfaces. The obtained results helped us to understand how the slow surfactant adsorption during foam generation can influence the mobility of interfaces and change foam drainage. To study different aspects of foam physics at the bubble scale simplified quasi-2D foams (monolayers of bubbles squeezed between two plates) are widely used. In this thesis a model to describe the geometry of a quasi-2D foam was introduced, this description was used to model the electrical and flow conductivities of such foams. In some applications (for example, in the paper and paint industries) foam formation can cause serious problems and suitable antifoaming agents need to be used. In my thesis the influence of gravity on the antifoaming efficiency of silicone oil droplets has been experimentally studied using parabolic flights. The results show that antifoam particles need gravity to be efficiently transported, and microgravity can render highly efficient antifoam practically useless. Being initially motivated by particle transport in foams, I have also looked at the sedimentation of solid particles in vertical and inclined glass capillaries.

No description available.

No description available.

Ploughed upland drains are straight prismatic channels of low aspect ratio. The drains are either uniformly or compositely roughened. In compositely roughened drains the bed and side-walls are differentially roughened although each roughness type is homogeneous. Upland catchments, containing extensive ploughed drainage networks, are particularly prone to flash flooding and increased sediment yield. However, the basic hydraulic data necessary to route flow through the drainage network and improve the engineering design of stable drainage channels are currently unavailable. A logarithmic flow resistance equation is developed for low aspect ratio channels, where the effective Nikuradse equivalent grain size is known. Testing against field data indicates that the relationship successfully predicts the resistance to uniform flow through upland drains. The performance of eight composite roughness formulae to predict the mean velocity in differentially roughened channels is compared. The composite roughness equations involve dividing the cross-sectional flow area into a number of sub-areas. The different methods of cross-sectional area division are considered and their effect on mean velocity prediction examined. Preferences are indicated concerning composite roughness equations which predict the mean velocity in channels of simple cross-sectional shape. Empirical equations are derived to determine the mean bed and side-wall shear stresses in straight symmetrical trapezoidal and rectangular open channels, with uniform or composite roughness. The model proposed is appropriate for stable sub-critical and super-critical flows. The equations are based on data collected from laboratory channels and should be cautiously applied to larger scale channels. Using the mean shear stress model, a design procedure is proposed to improve drainage channel stability.

Urbanisation, a process associated with industrialisation and development has been characterised by unsustainable impacts such as increased impervious surfaces, increased air pollution, increased use of natural resources, increased volume of surface run-off, decreased quality of surface run-off, and depletion of biodiversity and habitats. The effects of these impacts on the environment include climate change, flooding, erosion, pollution of water bodies, and destruction of aquatic life and biodiversity. Studies have shown that sustainable designs such as Sustainable Drainage Systems (SuDS) would help mitigate some of these effects sustainably. SuDS are natural drainage systems that simulate the natural drainage of a site/catchment and work in harmony to achieve increase in ground infiltration and treatment of runoff; and reduction in flow rates and volume of surface runoff, thereby improving storm water quality, reducing erosion, recharging groundwater, improving biodiversity and ultimately improving sustainability. However, sustainability of SuDS devices are questionable because their component parts involve the use of natural resources i.e. topsoil and gravel. The overall aim of this research was to evaluate the efficacy of the application of recycled/waste materials in performing at least as well as topsoil and gravel in vegetative SuDS, thereby improving water quality and overall sustainability. The materials applied were compost and recycled aggregates. In assessing their efficacy in vegetative SuDS, the risk these materials could pose to water quality was not overlooked but was considered in establishing an ideal model for the treatment of pollutants in vegetative SuDS. Results of this research showed that overall compost and recycled aggregates were able to perform at least as well as gravel and topsoil in vegetative SuDS in terms of characterisation, biofilm and vegetative development, and remediation of runoff pollutants thereby improving the sustainability of vegetative SuDS. Compared to gravel and topsoil, characterisation of compost and recycled aggregates was shown to be less expensive, less time consuming (except for recycled aggregates) and more sustainable, in terms of conserving natural resources. It was deduced that compost would be able to biodegrade organic pollutants in vegetative SuDS in varying conditions, compared to topsoil, thereby improving water quality. Vegetative growth in profiles containing compost were more prolific than those with topsoil alone, indicating that vegetative SuDS containing compost would attenuate stormwater and remediate pollutants by phytoremediation, better than topsoil. Results showed that compost and recycled aggregates performed as well as gravel and topsoil in remediating pollutants, with >98% of pollutants being retained mostly within the growth media, confirming that most pollutants are treated within the growth media of vegetative SuDS devices. This research was able to establish that SuDS components can be as unsustainable as components of conventional drainage systems in terms of their social, economic and environmental impacts; and that recycled materials could perform just as well as conventional materials, whilst improving their sustainability. This research further established that compost and recycled aggregates can be used in vegetative SuDS, such as swales, as literature has shown that the use of compost and recycled aggregates in vegetative SuDS has been limited to compost blankets and socks and substrates for green roofs. Suggestions for other waste materials that can be used instead topsoil and gravel in vegetative SuDS were also made. Results from this research were applied in the development of a swale model for the treatment of pollutants in vegetative SuDS.

Acid mine drainage (AMD) at Stockton Coal Mine, located near Westport, New Zealand, is generated from the oxidation of pyrite within sedimentary overburden exposed during surface mining. The pyrite oxidation releases significant acidity, Fe, and sulphate together with trace metals to the receiving environment. Aluminium is also elevated in drainage waters due to acid leaching from overburden materials. Thirteen AMD seeps emanating from waste rock dumps, and associated sediment ponds were monitored at Stockton Coal Mine to characterise water chemistry, delineate their spatial and temporal variability, and quantify metal loads. Dissolved metal concentrations ranged from 0.05-1430 mg/L Fe, 0.200-627 mg/L Al, 0.0024-0.594 mg/L Cu, 0.0052-4.21 mg/L Ni, 0.019- 18.8 mg/L Zn, <0.00005-0.0232 mg/L Cd, 0.0007-0.0028 mg/L Pb, <0.001-0.154 mg/L As and 0.103- 29.3 mg/L Mn and the pH ranged from 2.04-4.31. Currently this AMD is treated further downstream by a number of water treatment plants employing a combination of ultra fine limestone and calcium hydroxide; however, in the interest of assessing more cost-effective technologies, passive treatment systems were investigated for their treatment and hydraulic efficacy and as potential cost-effective options. Biogeochemical reactors (BGCRs) were selected as the most appropriate passive treatment system for ameliorating AMD at Stockton Coal Mine. Results of mesocosm-scale treatability tests showed that BGCRs incorporating mussel shells, Pinus radiata bark, wood fragments (post peel), and compost increased pH to ≥6.7 and sequestered ≥98.2% of the metal load from the Manchester Seep located within the Mangatini Stream catchment. The following design criteria were recommended for BGCRs incorporating 20-30 vol. % mussel shells as an alkalinity amendment: 1) 0.3 mol sulphate /m3 substrate/day for sulphate removal (mean of 94.1% removal (range of 87.6-98.0%)); 2) 0.4 mol metals/m3/day for metal (mean of 99.0% removal (range of 98.5-99.9%)) and partial sulphate (mean of 46.0% removal (range of 39.6-57.8%)) removal; and 3) 0.8 mol metals/m3/day for metal (mean of 98.4% removal (range of 98.2-98.6%) and minimal sulphate (mean of 16.6% removal (range of 11.9- 19.2%)) removal. At the maximum recommended loading rate of 0.8 mol total metals/m3/day an average of 20.0 kg/day (7.30 tonnes/year) of metals and 85.2 kg acidity as CaCO3/day could be removed from the Manchester Seep AMD by employing BGCRs. The design hydraulic residence time (HRT) would be 3.64 days. On an acidity areal loading basis, a design criterion of 65 g/m2/day was recommended. Tracer studies conducted on the BGCRs indicated ideal flow characteristics for cylindrical drumshaped reactors and non-ideal flow conditions for trapezoidal-shaped reactors indicative of shortcircuiting, channelised flow paths and internal recirculation. Consequently, this resulted in compromised treatment performance in the trapezoidal-shaped reactors. The relaxed tanks in series (TIS) model could be successfully applied to model the treatment performance of drum-shaped reactors; however, the model was unsuccessful for trapezoidal-shaped reactors. Because most pilot and full-scaled vertical flow wetlands (VFWs) have consisted of trapezoidal-prism basins excavated into the ground, the rate-removal methods previously recommended (e.g. mol metals/m3/day) should be applied to BGCR design, evaluation and operation rather than results of hydraulic and reactor modelling. Overall, a staged passive treatment approach is recommended. The first stage should consist of a sedimentation basin to remove sediment, the second stage a BGCR to remove acidity and metals and the third an aerobic wetland to provide oxygenation and tertiary treatment of metals (primarily Fe) from BGCR effluent. Preliminary analysis indicates that BGCRs are potentially a more cost-effective means of treating AMD at Stockton Coal Mine compared with the current active lime-dosing plant by over $125/tonne of acidity ($197/tonne for BGCRs versus $324/tonne for lime dosing (60% efficient)); however, their successful implementation would need to recognise current treatment goals, required areal footprint and inherent maintenance requirements.

No description available.

40 pp. / Managing stormwater is important to reduce flooding, keep people safe, maintain clean water, and to reduce soil erosion. Cities have built systems of streets, washes, channels, and stormdrains to manage stormwater and direct it to major washes. Because stormwater drains from small washes to these larger watercourses, keeping stormwater clean is also important. The next time it rains, consider how the rain affects you. Do you want to go outside and play in the raindrops and puddles? What happens to the streets in your neighborhood? Do you live near any washes that flow when it rains? Where does your stormwater go?

No description available.

No description available.