Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2012. / Recently much research and development has been done into the creation of desalination systems in South Africa, with particular emphasis on the commercialisation of desalination plants that serve local communities. This has been successful - there are currently plants running at Bitlerfontien, Bushmans River Mouth and Robben Island - although membrane fouling and scaling remains a problem associated with membrane desalination, as it does worldwide The aim of this study was to Investigate the performance of different type of antiscalants on artificially scaled membranes which we prepared inside the lab as well as on scaled membranes which were used in pilot plant. We used two type of anti-sealants in our research: Vitec 3000 and Zinc ions. The effects of these anti-sealants on the membrane were determind and the RO performances of the treated and untreated membrane compared. A suitable autopsy procedure was established and was then used to autopsy the XLE 4040 membranes. The autopsied membranes were characterized by scanning electron microscopy (SEM) and optical microscopy (OM). The SEM and OM results clearly showed that scaling had taken place: deposits were observed for both the shell and core samples, which were not present in the images of the untreated membrane, especially when looking at high SEM images magnification. Results also showed that the anti-sealants reduced the fouling and scaling on the membrane surface. As a result, the membrane rejection improved. Rejection and flux results indicated that commercial anti-sealant was more effective in preventing scaling than the Zinc ions. For Vitec anti-sealant case, the flux was in steady state at 36.8 Imh (5% less) after 5 hours compared to around 35 Imh (8% less) for zinc ions case. In addition; SEM images showed that less deposited particles are formed when the membrane was treated with commercial anti-sealant.

L’objectif de cette étude est de recycler du slurry, suspension silicatée, utilisé dans le domaine de l’électronique lors du polissage. Deux applications de polissage sont étudiées : le polissage silicium et le polissage tungstène. Pour ces deux applications, une caractérisation physico-chimique des slurries en amont et en aval du procédé de polissage a mis en exergue une importante dilution du slurry par de l’eau déionisée destinée au rinçage des wafers : une collecte ségrégée a ainsi été mise en place. Le procédé d’ultrafiltration permet une reconcentration de la silice. Toutefois ce procédé ne permet pas la récupération des composés dissous du slurry, qui restent pourtant essentiels au polissage et d’autant plus pour l’application tungstène : un ajustement chimique est donc développée avant réutilisation du slurry ainsi retraité. Pour le slurry tungstène, la matrice chimique étant plus complexe, deux types d’ajustement ont été testés dont les proportions ont été optimisées par une méthode de plans d’expériences.Concernant le slurry silicium, un prototype industriel a été installé et les résultats de polissage sont similaires au slurry POU sur un nombre significatif de plaques. La qualification industrielle a été réalisée. Ce prototype permet d’atteindre les objectifs de diminution de 30% de la consommation de slurry et de 40% des volumes d’effluents rejetés vers station d’épuration. / The chemical and mechanical polishing is a costly step in the process of microelectronic chips manufacturing. This study aims for recycle the silicate suspension named slurry by membrane processes. Both polishing applications are studied: the silicium and the tungsten polishing. A physical and chemical characterization before and after polishing process shows an important dilution of slurry by deionized water used for wafers rinsing. From CMP machine, a collect segregation of a concentrated effluent is realised by a diverter valve. Ultrafiltration has been chosen to reconcentrate silica but does not permit to recover the chemical compounds of the slurry which are essential to the polishing mainly to the tungsten application. Thus, retreatment process includes a collect segregation at the CMP outlet to decrease the dilution factor of slurry, an ultrafiltration step to concentrate silica and a chemical adjustment step. About tungsten application, the chemical media is more complex and two types of adjustment have been led. Firstly, a mix of POU and retreated slurry has been tested and secondly, an experiment of design with three important compounds of the slurry has been tested. Most CMP parameters are obtained in industrial specifications with the mix of POU and retreated slurry.Concerning the silicium slurry, an industrial prototype is installed and polishing results are similar to the original slurry for a significant wafers number. The industrial agreement is obtained. This prototype allows reaching a 30% decrease of slurry consumption and a 40% decrease of waste waters.

This diploma thesis deals with the efficiency of removal of pharmaceuticals from drinking water by selected adsorption materials. The first part describes sources of pharmaceuticals in drinking water and possible ways of contaminating water by pharmaceuticals. Subsequently, the pharmaceuticals most commonly found in the environment - nonsteroidal anti-inflammatory drugs, antibiotics, psychiatric drugs and sex hormones - are described in more detail. Next, the thesis describes the processes used for removal of pharmaceuticals. These are activated carbon adsorption, membrane processes and advanced oxidation processes. The last chapter of the theoretical part of the thesis deals with water treatment plants, where the technologies for removing drugs are already in operation. In the practical part of this thesis an experiment was performed and evaluated, for a purpose of comparing the efficiency of selected sorption materials in the removal of diclofenac from water. Filtrasorb F100, Bayoxide E33 and GEH were used.

The Master’s Thesis deals with the application of membrane technologies in the production of drinking water from the effluent of a municipal wastewater treatment plant (WWTP). There were two types of pressure-driven membrane processes selected – ultrafiltration and reverse osmosis, to achieve water production of the required quality. For the needs of the diploma thesis, an already existing pilot-scale membrane unit of the ASIO TECH Company l.t.d. was used. There were 44 physical, chemical and microbiological parameters observed to assess the quality of the produced water and also the input water (effluent from the WWTP). None of the afore mentioned parameters exceeded the limit values, more specifically the highest limit values issued by the Decree 70/2018 Coll. However, the produced water cannot be considered as drinking water because of its low mineralisation. Before its potential application in practise, it is therefore necessary to choose an appropriate method of remineralisation as well as to follow all the other legislative requirements for the drinking water, which have already been out of the scope within the Master’s Thesis.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / The process of salt replacement desalination proposed is believed to be able to produce vast quantities of fresh water be desalination. This method, which is a novel approach to minimizing the costs of saline water conversion, consists of the substitution of solutes in a solution to be desalted by a replacer chemical, and the low energy removal of that replacer chemical. The ultrafiltration of larger molecular sized replacer chemicals with high flux membranes increases the produce yield rate and reduces the corresponding energy requirement, with respect to reverse osmosis. In addition, the initial captial investment is less since no pressure constraining devices are required. The alteration of the osmotic pressure of the replacer solution within the process can also take advantage of energy savings through the utilization of an easily reversible reaction which synthesizes and breaks down a constituent that has a significant osmotic pressure difference between phases. Finally, the unusual process of fixed gel syneresis shows potential as a low energy salt replacement type process, but still requires extensive investigation.