No description available.

Revised; Originally Published: 2006 / 3 pp.

Revised; Originally Published: 2004, 2006 / 106 pp.

No description available.

<p>This study has shown that OH˙ radicals can be generated in an Fe/O2 cell from the electrode products via Fenton&rsquo / s reaction and used for water disinfection. The cell system in which the experiments were carried out was open and undivided and contained two electrodes with iron (Fe) as the anode and oxygen (O2) gas diffusion electrode. Typically, 100 ml of Na2SO4.10H2O (0.5M) solution was used as a background electrolyte. OH˙ radicals were produced in-situ in an acidic solution aqueous by oxidation of iron (II), formed by dissolving of the anode, with hydrogen peroxide (H2O2). The H2O2 was electrogenerated by reduction of oxygen using porous reticulated vitreous carbon (RVC) as a catalyst.</p>

Dissolution of arsenic bearing minerals in groundwater (used as drinking water) can lead to concentrations of &gt;0.05 mg/L of arsenite in many countries, causing serious health effects. Several existing technologies rely on coagulation and adsorption to remove the less toxic form of arsenate (As (V)) (easier to remove from solution than As (III) due to its anionic charge) and the use of harsh oxidants (e.g. ozone). In this work nanocrystalline titanium dioxide (TiO₂) has been used as a photocatalytic oxidant (PCO) to oxidise As (III) which also functions as an adsorbent with a high surface area to remove the As (V) from solution. Most previous research has monitored only As (III) removal from solution and the mechanism of PCO is a controversial topic.  The main aim of this work was to use X-ray Photoelectron Spectroscopy (XPS) to study the adsorption and speciation of arsenic adsorbed on TiO₂ following PCO.  Aims also included finding a suitable commercial TiO₂, characterisation of adsorption of As (V), PCO reactions under different conditions, speciation of arsenic adsorbed by XPS and preliminary studies of the mechanism of PCO and the binding of arsenic species to the surface.

Master of Science / Department of Animal Science and Industry / Micheal J. Brouk / Data obtained from 50 individual published studies recording water intake by dairy cattle were utilized in a meta-analysis to develop a prediction equation for free water intake (FWI). Studies were selected based on quantitative measurements of DMI, diet DM%, water intake (WI), and milk yield. Many of the studies determined FWI on multiple treatments resulting in 116 mean data points from the 50 studies. With the addition of Na in the meta-analysis, 40 data points were available from the studies to examine the effects of Na on FWI. The effects of DMI, ration water intake (RWI), and milk yield (MY) were used to develop a FWI prediction equation from the 116 data points. The effects of DMI, RWI, MY, and sodium intake were used to develop a second prediction equation from the 40 data points. These equations were then compared with five published FWI prediction equations from Castle and Thomas (1975), Dahlborn et al. (1998), Little and Shaw (1978), Murphy et al. (1983) and Stockdale and King (1983). This data set showed that the five published equations either over or under predicted (P < 0.05) FWI when compared the actual FWI calculated from the meta-analysis data points. It also showed that the equation developed from the meta-analysis data points is the more accurate in determining FWI from the data points selected from the studies. A second project was conducted with the fresh water data collected from 13 freestall (FS) and 11 dry lot (DL) Kansas dairies over a 10-year period (2000-2009). Fresh water was recorded from water pumping records. Data were first summarized annually by operation and then converted to a per cow per day basis prior to analysis. Data were then analyzed by using the mixed procedures of SAS. Fixed effects included in the model were dairy type (FS or DL) and year was considered a random effect. The DL dairies averaged 186 L/cow per day and were lower than the FS dairies which averaged 237 L/cow per day. Differences between DL and FS style dairies may have been due to differences in parlor fresh water usage or cow cooling systems.

M.Sc. / The removal of organic pollutants from industrial and municipal water is a great challenge to water providers worldwide. Some of these pollutants are very toxic and pose serious health risks to both humans and animals. Additionally, the presence of organic pollutants in the water often leads to the corrosion of turbines used for power generation at power stations. This obviously makes the power generation process less efficient and thus has cost implications, especially for the end user. Besides the corrosion of turbines, organic water pollutants impact on the cost of generating clean water. To this end, municipalities and industries sourcing water from Rand Water’s treatment plants and Eskom’s power stations (coal-fired power station) may be plagued by high water costs. Geosmin and 2-MIB are detectable by the human nose at concentration levels as low as 10 ng/L. These common water pollutants and are renowned for causing bad taste and odour in drinking water. Although geosmin and 2-MIB do not pose any serious health risks to humans, they impact on the aesthetic and consumer acceptability of drinking water. Currently available technologies such as activated carbon are unable to remove these pollutants to low levels (i.e. ppb levels). In our laboratories, we have found cyclodextrin-based polyurethanes to be effective in the removal of a range of organic pollutants from water to the desired ppb levels. However, these investigations were confined to water samples deliberately spiked with specific pollutants and have not been proven with "real" water samples. We sought to integrate data accumulated in the laboratory by testing and applying these polymers on a larger scale and on real systems. Cyclodextrin (CD) polymers were employed in the removal of 2-MIB, geosmin and other organic pollutants from water. The water was sampled from a coal-fired power station and Zuikerbosch Water Treatment Plant (Rand Water). After using Solid Phase Microextraction (SPME) for the extraction of organic pollutants from the water samples the organic pollutants were identified and quantified using Gas chromatography-mass spectrometry (GC-MS). The new cyclodextrin polymer technology was compared with treatment methods currently applied at both the power station and treatment plant. To determine the environmental friendliness of this technology, polymer degradation studies were also carried out. These entailed performing soil burial tests prior to the characterization of the polymers. Thermogravimetric analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and Braunner Emmet Tellet (BET) analysis were used for the characterization of the polymers. The techniques were also used to determine if any degradation modifications occurred on the polymeric material. The findings of the study are summarized below: • SPME extraction and GC-MS analyses of geosmin, 2-MIB and other pollutants were successfully accomplished. • The cyclodextrin polymers were effective in the removal of geosmin and 2-MIB (up to 90%) from water sampled at Zuikerbosch water treatment plant. The polymers remained effective (90%) in the absorption of geosmin and 2-MIB even when the water samples were spiked with a competing pollutant (i.e. humic acid). Activated carbon has been noted to have reduced adsorption capacity when humic acid is present in water. • The polymers demonstrated the ability to remove as much as 90% of organic pollutants from raw water compared to the 50% removed by the polyelectrolyte and optimum minimal polyaluminium chloride employed at the coal-fired power station. Analyses of the samples using TOC before and after treatment were accomplished. Reduction in the TOC was noted at the different sampling points after Eskom’s water treatment regime. • Results from the study indicated that the β-CD TDI polymers underwent a greater weight-loss during soil burial when first digested in sulphuric acid (ca. 50% maximum mass loss). On the other hand, β-CD HMDI polymers appeared to be unaffected by predigestion and experienced the same amount mass loss for the digested and undigested polymers (ca. 30% maximum mass loss). SEM studies revealed changes in the surface morphology of the polymers. Moreover, thermogravimetric analysis (TGA) gave an indication of polymer degradation under all soil burial conditions the polymer was subjected to.

This paper identifies factors that are associated with higher levels of public acceptance for recycled and desalinated water. For the first time, a wide range of hypothesized factors, both of socio-demographic and psychographic nature, are included simultaneously. The key results, based on a survey study of about 3000 respondents are that: (1) drivers of the stated likelihood of using desalinated water differ somewhat from drivers of the stated likelihood of using recycled water; (2) positive perceptions of, and knowledge about, the respective water source are key drivers for the stated likelihood of usage; and (3) awareness of water scarcity, as well as prior experience with using water from alternative sources, increases the stated likelihood of use. Practical recommendations for public policy makers, such as key messages to be communicated to the public, are derived. (authors' abstract)

The South African Constitution, brought about democratic and developmental reforms that gave local government certain responsibilities, the supply of water services, amongst others. According to Naidoo (2011), the provision of water services was a vital developmental process that worked towards quality service realization that local government was grappling with. In this research report, a qualitative research method of in-depth interviews was conducted on a small target group and a few municipality documents were analyzed. Mixed perceptions and a range of problems, amongst which capacity problems, were some of the findings identified by the research. The effects of non-provision of water services and the benefits of water provision were also dealt with in the report. Eighteen (18) years into democracy, the majority of rural municipalities were still experiencing problems in the provision of water services to poor communities. Other than the usual experiences of municipalities in the provision of water services, Nkomazi Local Municipality encountered capacity problems which were complicated by its predominantly rural nature.