Wool scouring is the first stage of wool processing, where unwanted contaminants are removed from freshly shorn wool. In most scouring machines wool is fed as a continuous mat through a series of water-filled scour and rinse bowls which are periodically drained. The purpose of this project is to mathematically model the scour bowl with the aim of improving efficiency. In this thesis four novel models of contaminant concentration within a scour bowl are developed. These are used to investigate the relationships between the operating parameters of the machine and the concentration of contamination within the scour bowl. The models use the advection-diffusion equation to simulate the settling and mixing of contamination. In the first model considered here, the scour bowl is simulated numerically using finite difference methods. Previous models of the scouring process only considered the average steady-state concentration of contamination within the entire scour bowl. This is the first wool scouring model to look at the bowl in two dimensions and to give time dependent results, hence allowing the effect of different drainage patterns to be studied. The second model looks at the important region at the top of the bowl - where the wool and water mix. The governing equations are solved analytically by averaging the concentration vertically assuming the wool layer is thin. Asymptotic analysis on this model reveals some of the fundamental behaviour of the system. The third model considers the same region by solving the governing equations through separation of variables. A fourth, fully two-dimensional, time dependent model was developed and solved using a finite element method. A model of the swelling of grease on the wool fibres is also considered since some grease can only be removed from the fibre once swollen. The swelling is modelled as a Stefan problem, a nonlinear diffusion equation with two moving boundaries, in cylindrical coordinates. Both approximate, analytical and a numerical solutions are found.

The purpose of this investigation was to integrate the knowledge and techniques of marine geotechnical engineering, underwater acoustic and optical observation into studying the engineering problems of artificial reefs off south-western coast of Taiwan (Fang-Liau ,Lin-Yang, Yung-An artificial reefs etc.) and the destruction of mooring system on farming cages caused by the interaction of wave-current system. The ultimate goal of this investigation was to understand the scouring activities of loosely and closely spaced artificial reefs; as well as, to evaluate the feasibility of using artificial reefs as deadweight anchoring devices for farming cages at Fang-Liau reef site. The results of this research were as follows: Fang-Liau artificial reef site: The maximum scouring depth can reach as deep as 2.2m around closely distributed reefs at this site. Only a few loosely deployed reefs were buried there, and the scouring depressions around these buried reefs had been filled up completely. To sum up, the behavior of scouring produced by the action of wave, current and typhoon around this site, merely limited to loosely distributed reefs, and the rim of closely distributed reefs. With the scouring time increasing, there were no obvious evidences for the burial of artificial reefs at this site. Lin-Yang artificial reef site: The scouring depressions around part of loosely deployed reefs expand as typhoons attacking at this site. The horizontal range of the scouring depressions can reach 92.3m in length, and parts of the reefs were buried during the process of scouring. Besides, as time went on, part of closely distributed reefs illustrated periodic variations of being buried by sediments with ripple marks, then shown up with evident height, and then buried again. To sum up, the behavior of scouring produced by the action of wave, current and typhoon around this site could cause the complete burial of the reefs. The possible procedures for the burial of reefs in the scouring depression were the actions of backfill of sandy sediments at this site. Yung-An artificial reef site: During summer time, especially with typhoons passed by, surficial sediments at this site were evident with mega ripple marks. The effects of scouring at this site were prominent than those at Fang-Liau reef site. The textures of surficial sediments were the major factor which induced this difference. Based on the considerations of safety of sliding, bearing capacity and overturning, the usage of artificial reefs as anchoring devices for farming cages could not satisfy the basic engineering requirements under the action of extreme wave and current. This research suggested the usage of cubical concrete block with shear keys for anchoring devices on farming cages. The minimum buoyant weight of this block should reach 28.8 to 38.7ton. The problem regarding construction and deployment techniques of this block need further considerations.

The use of staged scouring aeration to reduce energy for membrane fouling was studied using one pilot-scale submerged membrane bioreactor to treat municipal wastewater. The experiments were conducted by varying each of permeate fluxes, scouring air scouring intensities and sequence during both permeation and relaxation periods while keeping other factors same. The critical and recoverable fluxes were measured by the stepwise flux method. Mixed liquor, permeate and filtrate was characterized by analysing COD, cTOC, SMP contents, etc. The recorded transmembrane pressure data were used to calculate the fouling resistance after relaxation and fouling rate of each cycle. The results showed that when operated at relatively high permeate flux rate, membrane fouling could be effectively controlled by using relatively lower air scouring intensity and/or less infrequent aeration sequence during the permeation combined subsequently with more vigorous and frequent air scouring during the relaxation. At lower permeate flux rate with good permeability sludge, membrane fouling was effectively controlled by relatively low air scouring intensity and/or relatively infrequent aeration sequence during both permeation and relaxation periods. For each sludge condition, an optimal combination of cyclic air scouring intensity and sequence existed which could minimize the aeration energy consumption while maintaining effective fouling control. The frequency of aeration sequence plays a more dominant role than the air scouring intensity during the permeation in aeration optimization. / GE Water & Process Technologies Natural Sciences and Engineering Research Council of Canada

The increasing cost of effluent treatment in the wool scouring industry is rapidly becoming a determining factor in the viability of existing scouring operations and new installations alike. This thesis details the development of an integrated effluent treatment process capable of treating the worst polluted effluent from a wool scour "heavy flow-down", to the point where it can either be economically discharged to local trade waste sewer, or directly discharged to river or ocean outfall with minimal environmental impact. The existing proprietary chemical flocculation process, Sirolan CF™, was improved by the addition of a bio-flocculation stage and turbidity monitoring and control, and the product from this process fed to an aerobic biological treatment system based upon the traditional activated sludge process. The biological treatment process was found to remove up to 98% of the BOD5 loading from the pre-treated liquor with a hydraulic residence time of at least 50 hours being required in the aerobic digestion vessels. A residual biorefractory COD of approximately 3,600mg/L was identified which could not be removed by biological treatment. When operating continuously, the biological process was observed to metabolically neutralise the pH 3.0 - 4.5 feed from the chemical flocculation system to pH &gt 7.0 without the need for supplemental addition of neutralising agents such as sodium hydroxide. This in itself provides a significant economic incentive for implementation of the process. Kinetic analysis of the biological process carried out under controlled laboratory conditions using a Bioflo 3000 continuous fermentor showed that the bio-chemical process followed substrate inhibition kinetics. An appropriate kinetic model was identified to represent the behaviour of the substrate degradation system, and modified by inclusion of a pseudo toxic concentration to account for the effect of pH inhibition upon the biological growth rate. The process was verified both at pilot plant scale and at demonstration plant scale at an operational wool scour. The demonstration plant was of sufficient size to handle the full heavy effluent flow-down from a small wool scour. At the time of publishing three full-scale effluent treatment systems based on this research had been sold to both domestic and international clients of ADM Group Ltd. who funded the research.

No description available.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18560号 / 工博第3921号 / 新制||工||1602(附属図書館) / 31460 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 中川 一, 教授 藤田 正治, 准教授 川池 健司 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Membrane BioReactor (MBR) is a wastewater treatment method which combine both biological and physical cleaning. In the membrane tank there is membrane fibres which physically separate wastewater from containing organic material. This causes the membrane fibres to easily build fouling. A measure that can describe membrane fouling, is the pressure across the fiber membranes (transmembrane pressure). The higher the pressure, the dirtier the fiber membranes. Therefore the fiber membranes need to be cleaned frequently. A current applying cleaning method, membrane air scouring, works by releasing air bubbles from the bottom of the tank to remove organic fouling from the membrane fibres. Membrane air scouring accounts for a big part of the total energy consumption. Therefore research is needed to find development opportunities to counteract membrane fouling and to make membrane air scouring more energy efficient. In this master thesis, two different air scouring strategies are used in the membrane tank to reduce the development of the membrane fouling. The first aeration strategy, with lower air supply, was operated at a constant air supply of 5.04 m3air/m3permeate. The second aeration strategy, with higher air supply, varied instead the air supply linearly with increased incoming flow. The different aeration strategies were then compared with each other, and it was looked at which aeration strategy is the most energy efficient regarding energy consumption per permeate volume produced, to reduce membrane fouling.For three weeks, each aeration strategy was applied in the pilot plant at Himmerfjärdsverket. During the strategies, maintenance cleaning was done with oxalic acid, as the commonly used chemical sodium hypochlorite was not available. The transmembrane pressure in the membrane tank was analysed during the aeration strategies to investigate how the membrane fouling developed. The sludge properties of the water in the pilot plant were also analysed, to see if these had any influence on the membrane fouling. Energy calculations were also done to for quantify the energy consumption from the membrane air scouring.The thing that had the biggest impact on energy consumption was the size of the incoming flow. Then irreversible fouling of inorganic substances that clog the membrane pores. Finally, reversible fouling of organic material that forms cakelayers on the fibres. The investigation showed that the aeration strategy with the lowest air supply was enough to successfully suppress the membrane fouling and maintain a high permeability. In pilot-scale, consumed the air strategy with lower air supply 74 Wh/m3, while the higher air supply aeration strategy consumed 92 Wh/m3for the pilot-scale membrane air cleaning. At full scale, the aeration strategy with lower air supply is expected to consume 46 Wh/m3. In full scale, more frequent maintenance cleaning may need to be done, which means poorer filtration performance during washing periods. The recommendation is to test the aeration strategy with lower air supply and at the same time have more frequent maintenance cleaning, to investigate whether it is the most energy efficient option in the long term. / Membrane BioReactor (MBR) är en vattenreningsteknik som tillämpar både biologisk och fysisk vattenrening. I membrantanken finns det membranfibrer som fysiskt separerar avloppsvattnet från det innehållande organiska materialet. Detta får membranfibrerna att lätt bli nedsmutsade. Ett mått som kan beskriva membrannedsmutsningen är trycket över membranfibrerna (transmembrantrycket). Ju smutsigare membranfibrerna är, desto sämre genomsläpplighet får de och trycket som krävs att suga vattnet igenom dem ökar. Membranfibrerna behöver därmed rengöras ofta. I dagsläget görs det med hjälp av luftbubblor som skaver bort smutsen som finns på fibrerna. Att lufta membrantanken kallas membranluftrengöring och står för en stor del av reningsteknikens totala energiförbrukning. För att göra MBR-processen till en mer energieffektiv vattenreningsteknik, behöver kunskapen öka om hur nedsmutsningen av membranen kan motverkas och membranluftrengöringen bli mer effektiv.I detta examensarbete tillämpas två olika strategier för att lufta membrantanken. Den första luftningsstrategin, med en lägre lufttillförsel, drevs med en konstant lufttillförsel på 5,04 m3luft/m3permeat. Den andra luftningsstrategi, med en högre lufttillförsel, varierade istället lufttillförseln linjärt vid ökat inkommande flöde av avloppsvatten. De olika luftningsstrategierna jämfördes sedan med varandra med avseende på vilken luftningsstrategi som är mest energieffektiv med avseende på energiförbrukning per producerad permeatvolym.I tre veckor tillämpades varsin luftningsstrategi i pilotanläggningen på Himmerfjärdsverket. Under tiden utfördes det underhållsrengöring, dock med oxalsyra, eftersom den vanligtvis använda kemikalien natriumhypoklorit inte var tillgänglig. Transmembrantrycket i membrantanken analyserades under luftningsstrategierna för att utreda hur membrannedsmutsningen utvecklat sig. Slamegenskaperna för vattnet i pilotanläggningen analyserades också, för att se om dessa hade någon påverkan på membrannedsmutsningen. Det gjordes därefter energiberäkningar för att ta reda på membranluftrengöringens energiförbrukning.Det som hade störst påverkan på energiförbrukningen visade sig vara storleken pådet inkommande flödet. Därefter irreversibel nedsmutsning som igensätter membranporerna. Sist kom reversibel nedsmutsning av organiskt material som bildar beläggningar på fibrerna. Utredningen visade att luftningsstrategin med lägst lufttillförsel var tillräcklig för att lyckas dämpa membrannedsmutsningen och bibehålla en hög genomsläpplighet. I pilotanläggningen förbrukade luftningsstrategin med lägre lufttillförsel 74 Wh/m3, medan luftningsstrategin med högre lufttillförsel förbrukade 92 Wh/m3. I fullskala förväntas luftningsstrategin med lägre lufttillförsel förbruka 46 Wh/m3. I fullskala kan mer frekvent underhållsrengöring behöva göras, vilket innebär sämre filtreringsprestanda under tvättperioderna. Rekommendationen är att testa luftningsstrategin med lägre lufttillförsel och samtidigt ha mer frekvent underhållsrengöring, för att utreda om det är det mest energieffektiva alternativet på lång sikt.

yes / River morphological dynamics are complex phenomena in natural and environmental flows. In particular, the sediment transport around braid mid-channel bars has not gained enough understanding from previous research. The effect of submergence ratio on the turbulence behavior in the proximity of the bar has been investigated in this study. The spatial distribution of turbulent flow in the proximity of bar has been studied by plotting the depth-averaged two-dimensional contours of turbulent kinetic energy. The high value of TKE has been observed in regions just downstream from the bar. It is due to the vortex shedding occurring in that region. The interaction of sweep and ejection events have been analyzed using the parameter Dominance Function obtained from the ratio of occurrence probability of ejection events to the occurrence probability of sweep events. This outcome indicates that the depth averaged parameter Dominance Function has successfully predicted the high scouring region which makes it an ideal parameter for analyzing the scour phenomena in real-world water management projects. The high scouring zone lies in the close proximity of the bar. This shows that the scouring effect from the bar is limited to its close region. The magnitude of scouring occurring at the upstream region of the bar also increases with the increment of submergence ratio. The relationship of quadrant event inclination angles with the sediment transport occurring in the proximity of bar has been also studied, where an Angle Ratio parameter has been utilized for linking the bed elevation change with the inclination angle. The results indicate that the AR parameter has been successfully tested in this study to show its competence to represent the turbulent burst-induced bed sedimentation and scouring. / The author has confirmed that no changes were made to the content of this proof on publication, although the paper is watermarked uncorrected proof.

The aim of this research was to study the effect of pre-treatment and modification processes on the properties of hemp cellulose fibre for biopolymer composites application. Hemp fibres have been modified by various extraction, swelling, chemical and enzymatic treatments. The morphology and mechanical properties of the modified fibres have been measured. Biopolymer composites have been prepared using the modified fibres and matrices of cellulose acetate butyrate and cellulose solutions derived from hemp. The first fibre treatment employed was acetone extraction and mercerization. A low pressure acrylonitrile grafting initiated by azo-bis-isobutylonitrile was performed using alkali treated fibre. The AN grafted fibres had no transformation of crystalline structure as observed after mercerization. The mechanical properties performed by a single fibre test method were strongly influenced by the cellulose structure, lateral index of crystallinity, and fraction of grafting. Bioscouring of hemp using pectate lyase (EC 4.2.2.2), Scourzyme L, was performed. Greater enzyme concentration and a longer treatment improved the removal of the low methoxy pectin component. Removal of pectate caused no crystalline transformation in the fibres, except for a slight decline in the X-ray crystalline order index. Smooth surfaces and separated fibres were evidence of successful treatment. The shortening of fibre by grinding and ball-milling was introduced to achieve a desired fibre size. An increase in the milling duration gradual ly destroyed the crystalline structure of the cellulose fibres. An increase in solvent polarity, solvent-fibre ratio, agitation speed and drying rate resulted in the rearrangement of the ball-milled cellulose crystalline structure to a greater order. The thermal degradation behaviour of hemp fibres was investigated by using TGA. The greater activation energy of treated hemp fibre compared with untreated fibre represented an increase in purity and improvement of structural order. The all hemp cellulose composites were prepared by an introduction of fibres into 12% cellulose N-methyl-morpholine N-oxide (NMMO) solution and water-ethanol regeneration. A broadening of the scattering of the main crystalline plane, (002) and a depression of the maximum degradation temperature of the fibres were observed. These revealed a structural change in the fibres arising from the preparation. The mechanical properties of composites depended on size, surface area, crystallinity and the structural swelling of the fibres. Composites of cellulose acetate butyrate (CAB) and modified hemp fibres were prepared. Composites containing pectate lyase enzyme treated fibres showed better mechanical property improvement than untreated and alkali treated fibres respectively.

Artificial reefs are becoming a popular biological and management component in shallow water environments characterized by soft seabed, representing both important marine habitats and tools to manage coastal fisheries and resources. An artificial reef in the marine environment acts as an open system with exchange of material and energy, altering the physical and biological characteristics of the surrounding area. Reef stability will depend on the balance of scour, settlement, and burial resulting from ocean conditions over time. Because of the unstable nature of sediments, they require a detailed and systematic investigation. Acoustic systems like high-frequency multibeam sonar are efficient tools in monitoring the environmental evolution around artificial reefs, whereas water turbidity can limit visual dive and ROV inspections. A high-frequency multibeam echo sounder offers the potential of detecting fine-scale distribution of reef units, providing an unprecedented level of resolution, coverage, and spatial definition. How do artificial reefs change over time in relation to the coastal processes? How accurately does multibeam technology map different typologies of artificial modules of known size and shape? How do artificial reefs affect fish school behavior? What are the limitations of multibeam technology for investigating fish school distribution as well as spatial and temporal changes? This study addresses the above questions and presents results of a new approach for artificial reef seafloor mapping over time, based upon an integrated analysis of multibeam swath bathymetry data and geoscientific information (backscatter data analysis, SCUBA observations, physical oceanographic data, and previous findings on the geology and sedimentation processes, integrated with unpublished data) from Senigallia artificial reef, northwestern Adriatic Sea (Italy) and St. Petersburg Beach Reef, west-central Florida continental shelf. A new approach for observation of fish aggregations associated with Senigallia reef based on the analysis of multibeam backscatter data in the water column is also explored. The settlement of the reefs and any terrain change are investigated over time providing a useful description of the local hydrodynamics and geological processes. All the artificial structures (made up by water-based concrete for Senigallia reef and mainly steel for St. Petersburg Beach reef) are identified and those showing substantial horizontal and/or vertical movements are analyzed in detail. Most artificial modules of Senigallia reef are not intact and scour signatures are well depicted around them, indicating reversals of the local current. This is due to both the wind pattern and to the quite close arrangement of the reef units that tend to deflect the bottom flow. As regards to the St. Petersburg Beach reef, all the man-made steel units are still in their upright position. Only a large barge shows a gradual collapse of its south side, and presents well-developed scouring at its east-northeast side, indicating dominant bottom flow from west-southwest to east-northeast. While an overall seafloor depth shallowing of about 0.30 m from down-current deposits was observed for Senigallia reef, an overall deepening of about 0.08 m due to scour was observed at the St. Petersburg Beach reef. Based on the backscatter data interpretation, surficial sediments are coarser in the vicinities of both artificial reefs than corresponding surrounding sediments. Scouring reveals this coarser layer underneath the prevalent mud sediment at Senigallia reef, and the predominant silt sediment at St. Petersburg Beach reef. In the ten years of Senigalia reef study, large-scale variations between clay and silt appear to be directly linked to large flood events that have occurred just prior to the change. As regards the water column investigation, acoustic backscatter from fish aggregations gives detailed information on their morphology and spatial distribution. In addition, relative fish biomass estimates can be extrapolated. Results suggest that most of the fish aggregations are generally associated with the artificial modules showing a tendency for mid- and bottom-water depth distribution than for the surface waters. This study contributes to understanding the changes in artificial reefs over time in relation to coastal processes. Moreover, the preliminary results concerning the water column backscatter data represents progress in fisheries acoustics research as a result of three-dimensional acoustics. They demonstrate the benefits of multibeam sonar as a tool to investigate and quantify size distribution and geometry of fish aggregations associated with shallow marine habitats.