Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xii, 105 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 71-73).

Thesis (M. Sc.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on July 15, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Geotechnical Engineering, Department of Civil and Environmental Engineering, University of Alberta. Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xi, 110 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 87-92).

Thesis (Masters Diploma (Technology)--Cape Technikon, Cape Town,1993 / Various experimental and established membranes were tested on industrial effluents. Ultrafiltration, reverse osmosis and nanofiltration membranes were used in various applications. Research was done on aspects such as the cleaning of fouled membranes, production quality control and process development. Polyvinyl alcohol ultra-thin-film reverse osmosis membranes were manufactured for the desalination of brackish water to a potable standard. The membranes were manufactured in the tubular configuration. Experimental ultrafiltration, reverse osmosis and nanofiltration membranes were tested on cooling water blowdown on a laboratory-scale. On-site testing was done directly on the effluent at a later stage. A s!udy was also conducted to determine the effect of gel-polarization on membrane performance. The gel-layer model was used to predict the limiting flux of specific membranes. Membrane processes were also applied in the fractionation of wine-lees to provide usable by-products such as yeast cells and potassium bitartrate. Ultrafiltration membranes operated in diafiltration mode were used to "wash" the slurry at different solid concentrations. The bitartrate-rich permeate collected from ultrafiltration was then concentrated using reverse osmosis and nanofiltration to allow subsequent precipitation of the product.

Empirical observation of filter beds at South African water treatment plants showed that the filters were insufficiently cleaned by the backwash system and that media losses were unexpectedly high. Specific deposit tests developed by the RAU Water Research Group indicated that the dirtiness correlated with the organic content of the water being treated. This led to the hypothesis that biofilm is present on the media, somehow causing both the media loss and the difficulty to attain efficient backwashing. Biofilm consists of organisms surrounded by a sticky, gelatinous polysaccharide matrix. This matrix, also known as extra-cellular polymeric substances (EPS), is the bulk (50-90%) of the biofilm. Biofilm plays an important role in the establishment and maintenance of organisms in a hostile environment. From the above it doesn¡¦t make sense trying to measure biofilm from the numeration of the organisms. A more reliable direct but tedious measure is quantifying the EPS. A new alternative method developed by the RAU Water Research Group is to mechanically strip the specific deposit off the filter media and then determine the organic fraction by combusting the sample at 500¢XC. Two aspects of mechanical behaviour are deemed important in this study. First, headloss, because an under prediction in headloss will result in a higher than expected backwash frequency. Second, bed expansion, because an under prediction in bed expansion will lead to media washout. Literature indicates that both headloss and bed expansion increase with increasing biofilm growth. However, all those studies were conducted at waste water treatment plants with high organic and solids loading. With the exception of one reference which only discusses headloss, nothing on this topic is available in the literature for potable water treatment. Mathematical models were used to reduce the data from multiple headloss and bed expansion experiments. For the headloss data the Ergun equation was used and the sphericity (ƒÚ) was retained as the only unmeasured calibration constant. For the bed expansion data the Dharmarajah equation was used and the sphericity was retained as the only unmeasured calibration constant. Calibration of the mathematical models was done with least square fitting. The two values of sphericity as determined by Ergun and Dharmarajah are not necessarily the same for the same media sample. The sphericity was used as a calibration constant without any physical meaning, which accounts for different sets of complex unknowns. Samples for experimental work were drawn from full scale operating water treatment plants. The treatment plants were spread over four provincesof South Africa with different raw water sources, but using approximately the same media. The sampling was done on three occasions, Winter 2003, Summer 2003 and Winter 2004, to cover the extreme temperatures experienced in South Africa. Samples collected at the plants were tested for headloss and bed expansion, then transported back to the laboratory and placed in the oven for 24 hours at 110¢XC. The sample was then sieved and the density determined. The headloss and bed expansion tests were then repeated in the laboratory. Parallel to these tests, EPS and volatile fraction quantification tests were done. Direct methods of measuring biofilm, namely EPS and volatile fraction, yielded measurable results, thereby confirming the presence of biofilm. Plants that had large quantities of EPS also had a high volatile fraction, thereby confirming the expectation that the volatile fraction is an excellent method to rapidly quantify biofilm presence. EPS made up 41% of the volatile fraction, which is roughly comparable with the 50-90% quoted in literature. Where large quantities of EPS were found at a plant, a high TOC reduction also occurred through the filters. The indirect methods of measuring biofilm, namely headloss and bed expansion, also yielded measurable results. The filter media with biofilm as sampled from the treatment plants had a higher headloss and bed expansion than the same sample after drying and sieving, which resembles virgin filter media. The sphericity values for headloss decrease by as much as 26% which translates to a headloss gradient increase of 150mm/m at typical filtration rates. The sphericity values for bed expansion decrease by as much as 18% which translates to a bed expansion increase of 17% at normal backwash rates. The conditions at the treatment plants sampled suggest that biofilm growth is stimulated by eutrophic raw water and the presence of pre-ozonation and inhibited when the high pH lime process is used. The mechanism which causes the increased headloss and bed expansion with increased biofilm is hypothesised to be media grains sticking together causing clumping, and not grains which are individually and uniformly covered with a smooth, uniform layer of biofilm. Designers can compensate for this increase in headloss and bed expansion in two ways. They could either apply a correction factor after application of the models to allow for more headloss or bed expansion during eventual plant operation, or they could adjust parameters within the models to account for the larger headloss or bed expansion. As the surface area sphericity was used as a calibration factor in this study and could account for different sets of complex unknowns, it is suggested that this factor is used for adjustment of the model. Operational practice in South Africa often includes in-situ chlorine or acid treatment to alleviate the problem of dirty filter beds. In this study, however, where high and efficient backwash rates were used during tests, no significant improvements in media cleanliness could be attributed to the use of either chlorine or acid. It seems that a good backwash system doesn¡¦t need such remediation, but plants with a backwash system which underperforms might find such remediation useful. / Prof. J. Haarhoff

The aim of this project was to investigate the usage of manganese dioxide ore as a bio-filter media to remove metabolites in aquaculture closed system, and to determine whether manganese toxicity would at the same time represent a risk to fish. Initial work investigated the physical properties of manganese dioxide and its chemical interaction with ammonia and nitrite in the absence of biological activity. Subsequently, two pilot-scale pressurised filters were installed in a commercial scale hatchery in order to compare the metabolite removal performance of manganese dioxide against silicate sand in the presence of biological activity commonly found in aquaculture conditions. The investigation suggests that Mn medium is more reliable in converting ammonia to nitrate without producing a residual output of nitrite. The superior performance ofMn media compared with sand appears to be mainly related to the physical structure of the manganese ore. Furthermore, the Mn medium did not appear to be soluble in the ambient conditions normally found in aquaculture-closed system. From the design point of view, due to the higher ammonia and nitrite removal rates, a shorter retention time and a lower volume of media are required in the case of manganese dioxide technology compared with sand media. As a result, it is much easier to size a biofilter with Mn media. Manganese systems have a comparable total costs to conventional sand media, but using the Mn technology provides a more reliable control of toxic nitrite, thereby reducing risks offish loss and hence with reduced expected production costs.

This thesis contains the results and discussion of an exploratory investigation into the application of Crossflow Microfiltration (CFMF) for solid/liquid separation in biological wastewater treatment systems. The principal objective of the study was to assess the influence of CFMF on the performance of identified biological wastewater treatment systems. It was not the objective to optimise filtration performance. A literature review indicated that the crossflow mode of filtration has been widely accepted as a unit operation in the fermentation industry. The filtration mode is now being applied not only for solid/liquid separation but also for separations on a molecular and ionic level. Very few applications of crossflow filtration in the context of biological wastewater treatment solid/liquid separation are reported in the literature. The reasons for this limited experience would appear to be the scale involved and the perceived high costs; separations in the fermentation industry are usually conducted at relatively small scale (laboratory or pilot-scale) and involve high-value products, justifying high capital and operating costs. Also, the high level of separation performance attained is perhaps not necessary for many wastewater treatment applications. No doubt these reservations are largely valid. However, these arguments cannot be applied equally to all filtration methods and wastewater treatment schemes. For example, the costs of microfiltration are substantially less than ultrafiltration or reverse osmosis, and in certain cases effluents with extremely low suspended solids contents may be required. In the light of these observations an investigation of CFMF for solid/liquid separation in biological wastewater treatment systems appears justified. Two biological treatment systems were selected for study: the Upflow Anaerobic Sludge Bed (UASB) reactor and the Activated Sludge system. The envisaged benefits accruing from the application of CFMF were different in each case.

No description available.

M. Tech. Engineering Chemical. / Developes and evaluate next generation antimicrobial filtration systems based on oligodynamic nanoparticles for complimentary water disinfection systems (CDWS) in under developed regions

Dissertation (Ph.D.)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The deposition of platinum catalyst on cation-exchange membranes was achieved by a counter diffusion deposition method known as the Takenaka- Torikai method. The morphology of the platinum catalyst on the membranes were controlled by varying the conditions of the platinum deposition process, such as, temperature, type of reducing agent and concentration of the platinic acid solution. The effect of the sonication of platinic acid solution and the pre-treatment of membranes on the morphology of a platinum catalyst was also investigated. Platinum loading on cation-exchange membranes was determined by UV spectrophotometric and gravimetric analyses. Suitable conditions for the quantitative determination of the platinum loading on membranes by UV spectrophotometric analysis was established through the development of a protocol. Membranes were characterised using different techniques such as, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Infrared spectrometry (IR), Dielectric analysis (DEA) and Brunauer Emmett Teller adsorption (BET). The roughness profile of a platinum catalyst embedded on a membrane was explored by various statistical methods. The statistical analysis of various data sets for a surface of a platinum-containing membrane was investigated using the Hurst exponent. The effect of surface modification of membranes on the deposition process, as well as the morphology of the platinum catalyst, was investigated. Membranes were modified with ethylene diamine (EDA) and cetyltrimethylammonium bromide surfactant. Modification of membranes with cetyltrimethylammonium bromide surfactant resulted in a unique textured platinum catalyst. The electrochemical "switching" phenomenon was investigated for EDAmodified membranes and EDA-modified membranes embedded with platinum catalyst. The "switching" phenomenon was observed in i-V cyclic curves, which were obtained by galvanodynamie measurements. The application of electro catalytic membrane systems in the anodic oxidation of water was investigated by electrochemical techniques such as galvanostatic and cyclic voltammetric measurements. / AFRIKAANSE OPSOMMING: Die deponering van 'n platinum katalis op katioon-uitruil membrane is suksesvol gedoen d.m.v. die Takenaka-Torikai metode. Die morfologie van die platinum katalis op die membrane is gekontrolleer deur variasie van die kondisies van die platinum deponeringsproses, bv. temperatuur, tipe reduseermiddel gebruik en konsentrasie van die platiensuuroplossing, asook die ultrasonifikasie van die platiensuuroplossing en voorafbehandeling van die membrane. UV spektrofotometriese asook gravimetriese analitiese metodes is gebruik om die platinumlading op katioon-uitruil membrane te bepaal. Geskikte kondisies vir die kwantitatiewe bepaling van die platinumlading op membrane d.m.v. UV spektrofotometriese analise is ontwikkel deur die skep van 'n protokol. Membrane is gekarakteriseer d.m.v. die volgende tegnieke: Atoomkrag Mikroskopie, Skanderingselektron Mikroskopie, Infrarooi Spektrometrie, di-elektriese analise en Brunauer Emmett Teller adsorpsie. Die skurtheidsprofiel van 'n platinum katalis op 'n membraan is ondersoek deur gebruik te maak van verskeie statistiese metodes. Statistiese analises van verskeie data stelsels van 'n platinum-bevattende membraan is ondersoek deur gebruik te maak van die Hurst eksponent. \ Die effek van oppervlakmodifikasie op membrane sowel as die deponeringsproses en morfologie van die platinum katalis is ondersoek deur die modifikasie van membrane met etileen diamien (EDA) en setieltrimetielammonium bromied as versepingsmiddel Die elektrochemiese omswaai van EDA-gemodifiseerde membrane sowel as gemodifiseerde platinum bevattende membrane is ondersoek d.m.v. galvanodinamiese metings. Die gebruik van elektro-katalitiese membraansisteme in die anodiese oksidasie van water is ondersoek deur gebruik te maak van elektrochemiese tegnieke, bv. galvanostatiese en sikliese voltammetriese metings.