Abstract Studies of phase speciation of trace metals were conducted in Kaohsiung harbor and coastal areas in April and May 2002. Water samples were collected from three different sampling stations to study the spatial distribution of metal species. Colloidal and truly dissolved subsamples were observed by cross-flow filtration treatment. The results show that TOC of seawater samples ranged from 4.17 mg/L to 7.17 mg/L. For trace metals, zinc had the highest concentration(7.21 £gg/L ¡ã14.14 £gg/L), followed by manganese(3.31 £gg/L ¡ã 11.73 £gg/L), copper(0.28 £gg/L ¡ã 7.57 £gg/L), lead(2.41 £gg/L ¡ã 4.41 £gg/L), nickel(1.78 £gg/L ¡ã 2.97 £gg/L). Highest concentrations of TOC and metals were observed in Kaohsiung harbor(S1), and the values decreased in the order of S1 ¡Ö S2 ¡Ö S3. Distribution of phase speciation of trace metals varied with location. Nickel existed in truly dissolved phase predominately(66 ¢Mat S1, 79.7 ¢Mat S2 and 84.6 ¢Mat S3). For the other metals, either particle or truly dissolved phase was the major species at each sampling station. For zinc, 56.1 ¢Mat S1 was in truly dissolved phase, 68.1 ¢Mat S2 and 59.6 ¢M at S3 were in particulate phase. For copper, 67.5 ¢Mat S1 was in particulate phase, 56.7 ¢Mat S2 and 89.9 ¢Mat S3 were in truly dissolved phase. For manganese, 56.3 ¢Mat S1 was in truly dissolved phase, 79.8 ¢Mat S2 and 72.1 ¢Mat S3 were in particulate phase. For lead, 51.7 ¢Mat S1 and 66.0 ¢Mat S3 were in truly dissolved phase, 63.5 ¢Mat S2 was in particulate phase. The percentages of TOC and metals in colloidal phase of the filter-passing pool were low at all sampling stations and decreased in the order of S1 ¡Ö S2 ¡Ö S3. They were found predominately in truly dissolved fraction. The results also show that Kaohsiung harbor (S1) had the highest percentage of colloidal fraction, followed by coastal water (S2), open sea (S3). Values of partition coefficient between colloids and true solution(Kc ) in the Kaohsiung harbor and nearby coastal areas were lower than the Kc values observed in Galveston Bay during July 1995.

<div>Bacteria which enter a viable but non-culturable state cannot be concentrated by enrichment. This means they may not reach a detectable concentration for PCR methods - especially in the presence of sample compounds which may act as PCR reaction inhibitors. An alternative strategy for concentration of bacteria from aqueous samples is explored in this work using tangential flow filtration. The effectiveness of this technology to concentrate pathogens from food-derived samples was previously demonstrated; however, losses of bacteria to the filtration system can still be high (i.e. recovery of bacteria is low). </div><div>The goal of this research was to maximize recovery of pathogenic microorganisms from hollow fiber filtration processes while also maximizing flux. In this way, high recovery filtration conditions could be selected while keeping filtration time low. It was hypothesized that flux would have relatively lower impact on final recovery of bacteria at high shear rates (27,000 1/s) which are sufficient to remove attached bacteria on surfaces. It was hypothesized that these high shear rates would not cause loss of bacterial viability, and the main cause of bacterial losses during filtration would be accumulation on the membrane surface.</div><div>To test these hypotheses, single fiber filter modules (both microfilters and ultrafilters with 0.5 mm inner diameter), were constructed and used to concentrate GFP-producing Escherichia coli at a wide range of flux conditions. Post-concentration, fluorescence micrographs of bisected hollow fibers illustrated patterns of bacterial accumulation along the length of the fiber. A simple recovery model was constructed to predict recovery as a function of flux and shear rate, and predictions were compared against the experimental data. </div><div>Both in the experiments and in the simple recovery model developed in this dissertation, recoveries near 90% were achievable at high shear rates when flux was ≤0.5 mL min-1 cm-2. This amounted to a 3-hour filtration time for a 225 mL sample. Compared to a filtration with only 30% recovery, detectable bacteria concentrations could be achieved with lower starting concentrations – ~5 CFU/mL starting concentration versus at least 15 CFU/mL. Given these high recoveries (determined with plating methods on agar) occurred at high pressure and shear conditions, it was determined the filtration did not affect bacterial viability. </div><div>In addition to using the model to predict recovery at various shear and flux conditions, it would be helpful to predict module designs or concentration strategies which could improve bacterial recoveries from the filter. One strategy, explored with preliminary data, was to pre-develop a layer of bacteria on the filter surface prior to concentrating samples. </div><div>Understanding and reducing the losses of bacteria during tangential flow filtration could enable detection of dilute levels of viable but non-culturable microorganisms; in addition, sensitivity of detection could be improved for quickly concentration culturable microorganisms in food and water samples.</div><div><br></div>

"Excessive discharge of heavy metals has been one of the major causes of water pollution worldwide. Various traditional methods of heavy metal removal have been devised but certain drawbacks like high cost, high energy requirement, and the production of toxic sludge have limited their use. Hence, biosorption is one of the alternative methodologies. This study combined biosorption and diafiltration in an attempt to optimize Polymer Enhanced Diafiltration to study copper removal from aqueous solutions by the use of a biopolymer, lambda-carrageenan. Lambda-carrageenan was studied as a biosorbent owing to properties such as low cost, good water solubility, non-gelling nature and the presence of sulfate groups which can sequester cations. Conditions for binding such as pH, temperature and concentration of copper and lambda-carrageenan were studied. Equilibrium dialysis experiments were performed to study the metal ion membrane transport kinetics and to determine the metal ion binding capacity and strength of the copper-biopolymer association. Rheological measurements were performed to determine how the viscosity of lambda-carrageenan changes with increase in shear stress and with increase in metal concentration. The solution was found to be shear thinning. However, with increase in metal concentration, viscosity was found to increase when high concentrations of polymer (8 g/L and 12 g/L) were used. Solution viscosity was found to decrease with increase in metal concentration when 4 g/L of polymer was used. Polymer Enhanced Diafiltration studies showed no leakage of the polymer through the membrane and no significant binding elsewhere in the PEDF system. It also showed an impressive retention of copper inspite of a rather high metal ion-polymer dissociation constant suggesting a yet not understood series of events occurring on the membrane of the PEDF system. Lambda-carrageenan is a linear polysaccharide, which might be stacking up on the membrane after forming layers, and not allowing any free metal ion to escape. Other reasons could be the sieving effect, degradation of the polymer due to shear and compaction of molecule on metal binding such that the polymer is not itself escaping through the membrane, but also not allowing the free metal ion to escape. Hence, this study suggests the need for more information on the metal-polymer interactions on the surface of the membrane by designing a direct observation experiment with a mini-tangential flow filtration system."

The tap-water treated by water treatment plants in southern Taiwan is coming from surface water of the rivers, subsurface stream and underground water of deep wells. The original raw water possesses were high level of hardness and ammonia- nitrogen solute due to affection by terrain, geology and human activities within water origin area. And considering the water quality from Kao-ping river origin is hard to control during in rain fall and dry season, we were to construction efficiency procedure of water treatment to obtain a high quality of drink water. There were high hardness and TDS from strata limestone of groundwater to increase treatment difficulty in southern Taiwan water treatment plant. Therefore, recommended that the influent water standards were limited hardness and silicate (SiO2) less than 300 mg/L and 15 mg/L, respectively. On the other hand, the metal substances Ca, Mg, Si and Al in influent water were 74.3 mg/L, 18.7 mg/L, 12.9 mg/L and 0.1 mg/L, respectively. Results show high inorganic substances that could increase the treatment loading. This project of the study, were make sure the problem of membrane clogging and fouling happened to the finest water treatment plants who use LPRO membrane system to remove the impurity in the influent water. Moreover, by accumulation of processes operation experience on site were according to water quality statistics data and membrane autopsy of single LPRO membrane by processes. In the same time, we prepared three single tube of RO membrane to experiment on site and collected data from before and after antifouling additive, that could find the membrane fouling and clogging results of the influent raw water. Obviously, the influent raw water quality into LPRO membrane is closely connected to the efficiency of treatment plant. The results show when the temperature decreased of influent raw water that could decrease the effluent volume from LPRO, because the water temperature affected by increase viscosity of raw water. The first part clogging substances of membrane were aluminum (Al), that could be use aluminate coagulant to make increase more aluminum. And the TOC value of the effluent were from 0.2 to 1.4 mg/L, that shows the effluent water was kept stably but UV254 value were have more than 75% efficiency. Results of organic analysis on LPRO effluent indicates the pretreatment process could leave annular structure organic. In other hand, when using EEFM to analysis the spectra sampling of organic of LPRO, there finding a lot low emission wavelength fluoresces of influent on EX/EM 230/340 and decrease the wavelength fluoresces value on EX/EM 280/330 and 240/340 by RO membrane system of LPRO. To be worth mentioning, when organism of sampling fluoresces value during high emission wavelength on EX/EM 240/400 nm was disappeared, that indicates RO membrane has good performance to separation organism of water. And results of elements analysis on RO membrane surface were using SEM and EDX have a lot aluminum and silicate on segment RO membrane module. Therefore, results show pretreatment process of coagulation and sedimentation could not treatment metal substances and organic efficiency, that was to effect directly cause to make the problems of membrane fouling and clogging.

No description available.

This research is a follow up to preliminary studies reported by Beier and Sego (2008) and the objective is to investigate laboratory scale dewatering of oil sands total tailings using cross flow filtration technology. A laboratory experiment was setup in Oil Sands Tailings Research Facility and tests were carried out under different operational conditions using different tailings. The experiments showed clean filtrate water generated under all test conditions. Coarser tailings and higher filter pipe porosity resulted in greater filtrate flux rate. The effect of slurry velocity, residual bitumen, and transmembrane pressure on cross flow filtration performance was also evaluated. A dimensional analysis was developed using the laboratory tests to establish the relationships between measured parameters and to assist and guide future experimental programs. / Geotechnical Engineering

Studies of phase speciation of trace metals were conducted in Kao-ping river estuary in September 2001 and May 2002. Influence of seasonal variation, salinity and organic carbon content on the trace metal¡¦s phase speciation were of special interest. Water samples collected from four different sampling stations were analyzed for their contents which include salinity, pH value, dissolved oxygen, turbidity, total organic carbon and trace metals. Subsamples observed by cross-flow filtration treatment were further analyzed for the contents of total organic carbon and trace metals. The results showed that manganese has the highest concentration( 8.23 ~ 291.24 £gg/L ), followed by zinc( 2.83 ~ 5.89 £gg/L), nickel( 1.69 ~ 5.82 £gg/L ), copper( 1.75 ~ 4.71 £gg/L ), lead( 0.27 ~ 0.89 £gg/L ) and cadmium( 0.01 ~ 0.27 £gg/L ). Cadmium existed in particulate phase predominately. Copper existed in truly dissolved phase predominately. Particle and truly dissolved phase were the major species of zinc, nickel, manganese and lead. Percentage of all metals in colloidal fraction of the filter-passing pool were low( 9 ~ 16 % for Cu, 5 ~ 21 % for Zn, 4 ~ 30 % for Ni, 2 ~ 38 % for Mn, 5 ~ 30 % for Pb and 8 ~ 34 % for Cd ), they were found predominately in truly dissolved fraction. Effect of seasonal variation was not significant on the distribution of trace metals. Percentage of all truly dissolved metals increased with increasing salinity, however, percentage of particulate metals decreased with increasing salinity ( except for Zn ). Values of partition coefficients between colloids and true solution( Kc ) were considerably higher than those between particles and true solution( Kp ) for all trace metals indicate a high complexation capacity and binding intensity of colloidal organic matter.

No description available.

This thesis focuses on the incorporation of carbon nanoparticles within continuous fibre reinforcements by liquid composite moulding processes, in order to provide enhanced electrical and delamination properties to the multiscale composites. The mechanisms controlling the flow and filtration of these nanoparticles during liquid composite moulding are studied, in order to develop a predictive 1-D model which allows design of the processing of these composite materials. Five different carbon nanoparticles at 0.25 wt% loading, three unmodified and one surface modified carbon nanotube systems and one carbon nanofibre system, were utilised to modify a commercial two-component epoxy resin utilised to impregnate carbon and glass reinforcements at high fibre volume fraction by resin transfer moulding. The dispersion of the nanofillers in the prepolymer was carried out by ultrasonication, high shear mixing or triple roll milling or a combination of the three. Electrical conductivity measurements of the carbon nanoparticle liquid suspensions during dispersion, alongside optical microscopy imaging and rheological analysis of these allowed the selection of the concentration of nanofiller and the appropriate dispersion technique for each nanoparticle system. The resin transfer moulding process required adaptation to incorporate the dispersion and modify degassing steps, especially when utilising unmodified carbon nanoparticles suspensions, due to their higher viscosity and tendency to be filtered. Nanoparticle filtration was identified by electrical conductivity measurements and microscopy of specimens cut at increasing distances from the inlet. Cake filtration was observed for some of the unmodified systems, whereas deep bed filtration occurred for the surface modified CNT material. Property graded composites were obtained due to filtration, where the average electrical conductivity of the carbon and glass composites produced increased by a factor of two or one order of magnitude respectively. The effect of filler on the delamination properties of the carbon fibre composites was tested under mode I. The results do not show a statistically significant improvement of delamination resistance with the presence of nanoparticles, although localised toughening mechanisms such as nanoparticle pull-out and crack bridging as well as inelastic deformation have been observed on fracture surfaces. Particle filtration and gradients in concentration resulted in non-linear flow behaviour. An 1-D analytical and a finite difference model, based on Darcy’s law accompanied by particle mass conservation and filtration kinetics were developed to describe the flow and filtration of carbon nanoparticle filled thermosets. The numerical model describes the non-linear problem by incorporating material property update laws, i.e. permeability, porosity and viscosity variations on concentration of retained and suspended particles with location and time. The finite difference model is consistent and converges to the analytical solution. The range of applicability of the analytical model is limited to lower filtration coefficients and shorter filling lengths, providing an approximate solution for through thickness infusion; whereas the numerical model presents a solution outside this range, i.e. in-plane filling processes. These models allow process design, with specified carbon nanoparticle concentration distributions achieved via modifying the nanofiller loading at the inlet as a function of time.

The nematode Caenorhabditis elegans is a model organism for understanding sensory molecules of multicellular organisms. Ovulating hermaphrodites produce putative pheromone(s) that cause male attraction. Because pheromones are produced in such small quantities, adult conditioned-media from large-scale synchronous culture is necessary to analyze these pheromones. Current protocols for culture synchronization have volume constraints that limit large-scale synchronous cultures and current methodology for adult conditioned-media production is impractical. Modification of Tangential Flow Filtration (TFF) systems was investigated for use as a method to increase the volume limits of bleach egg harvest for C. elegans culture synchronization. Also, an adult retention device built within the culture vessel was investigated to optimize the environment for aseptic conditioned-media production from dense large-scale C. elegans cultures. During this investigation, we have shown that synchronous C. elegans cultures for adult conditioned-media production can be grown at scales larger than reported before, with potential for further scale up. Our growth methodologies have also yielded denser cultures than previously achieved at large scales. Since rapid bleach harvesting appears to be the bottleneck for large-scale production of synchronous C. elegans cultures, our approach of using modified TFF systems with mesh to retain C. elegans eggs increased the amount of eggs that could be bleach harvested at one time. Using this method we have been able to achieve up to 5x103 synchronous C. elegans per mL at a 50L scale. Since scale-up of TFF is straightforward, our results suggest that the technique reported here can easily be applied to larger scale systems for production of adult conditioned-media for C. elegans. Further, the adult retention device within the culture vessel can ensure that the whole process remains aseptic.