Submitted in complete fulfillment for the Degree of Master of Technology: Biotechnology, Durban University of Technology, Durban, South Africa, 2014. / Among persistent organic pollutants, chlorobenzenes are some of the most frequently encountered compounds in aqueous systems. These compounds can enter the environment via natural and anthropogenic sources, and are ubiquitous due to their extensive use over the past several decades. Several chlorobenzene compounds, once in the environment, can biologically accumulate, and are reputed to be carcinogens and extremely hazardous to health. Several chlorobenzenes are listed as priority pollutants by the United States Environmental Protection Agency. Excessive exposure to these compounds affects the central nervous system, irritates skin and upper respiratory tract, hardens skin and leads to haematological disorders including anaemia. In spite of these harmful effects, chlorobenzenes are still used widely as process solvents and raw materials in the manufacture of pesticides, chlorinated phenols, lubricants, disinfectants, pigments and dyes. In the light of the above, it is imperative to monitor the levels of chlorinated benzenes in all types of surface waters, using low-cost but sensitive methods of preconcentration and detection. In this study, a simple and relatively cheap preconcentration method using direct immersion solid phase microextraction (DI-SPME) followed by gas chromatography equipped with a flame ionisation detector (GC-FID) was developed for the analysis of 7 chlorinated benzenes in dam water. Experimental parameters affecting the extraction efficiency of the selected chlorobenzenes, such as fibre type, sample size, rate of agitation, salting-out effect and extraction time, were optimised and applied to the Grootdraai Dam water samples. The optimised method comprises the use of a 100 µm polydimethylsiloxane (PDMS) fibre coating; 5 ml sample size; 700 revolutions per minute rate of agitation and an extraction time of 30 minutes. The calibration curves were linear with correlation coefficients ranging from 0.9957–0.9995 for a concentration range of 1–100 ng/ml. The respective limits of detection and quantification for each analyte was as follows: 1,3-dichlorobenzene, 0.02 and 0.2 ng/ml; 1,4-dichlorobenzene, 0.04 and 0.4 ng/ml; 1,2-dichlorobenzene, 0.02 and 0.2 ng/ml; 1,2,4-trichlorobenzene, 0.3 and 2.7 ng/ml; 1,2,4,5-tetrachlorobenzene, 0.09 and 0.9 ng/ml; 1,2,3,4-tetrachlorobenzene, 0.07 and 0.7 ng/ml; pentachlorobenzene, 0.07 and 0.7 ng/ml. Recoveries ranged from 83.6–107.2% with relative standard deviation of less than 9%, indicating that the method has good precision, is reliable and free of matrix interferences. Water samples collected from the Grootdraai Dam were analysed using the optimised conditions to assess the potential of the method for trace level screening and quantification of chlorobenzenes. The method proved to be efficient, as 1,3 dichlorobenzene, 1,4-dichlorobenzene and pentachlorobenzene were detected at concentrations of 0.4 ng/ml, 1.7 ng/ml and 1.4 ng/ml, respectively.

Ultrapure water is becoming increasingly important to the semiconductor, pharmaceutical and power industries. Stricter industrial requirements concerning water purity can be realized from pilot scale research. Such a system was designed and operated to determine improved methods to characterize and remove organic contaminants in industrial scale ultrapure water systems. Theoretical modelling of the polishing loop was performed for variable order kinetics; intrinsic reaction parameters were developed, and are potentially scaleable to larger systems. Application of the population balance to the actions of process components on organic particle distributions generated novel oxidation and fragmentation parameters that are scaleable to larger systems. Optimization of bacterial growth media resulted in the increased detection of viable bacterial concentrations. A significant fraction of TOC in the polishing loop was found to exist as assimilable organic carbon; the action of process components, thought to remove contaminants, can generate bacteria nutrients from more complex organics. The situating of a polymeric filter before a UV unit resulted in increased removal of organic contaminants; reversing the sequence enhanced the removal of low molecular weight and low charge to mass ratio compounds. The combination of UV-185 and dissolved ozone resulted in synergistic removal of organic contaminants from ultrapure water. The invention of a novel catalytic filter designed to physically separate and then oxidize contaminants resulted in enhanced removal of organics from ultrapure water. A study of viruses in ultrapure water showed that UV-185 and ozone effectively removed viruses, yet ion exchange gave only two orders of magnitude removal in viable counts. This research may be used to augment present systems and/or design new systems. Continued research along the lines specified in this document will generate further understanding of ultrapure water and ultrapure water systems.

A variety of hazardous organic compounds are present in leachate from landfill sites that accept medical and industrial chemical waste. Most of these compounds find their way into nearby streams, rivers and dams, posing a threat to the ecosystem. In the present work two hazardous organic compounds, namely, m-xylene and 2-chloroethanol were chosen to react with ozone gas at different experimental conditions. The ozone initiated oxidation of m-xylene and 2-chloroethanol in solvent free conditions were investigated as a function of time. Gas chromatographic analysis of ozonated m-xylene, showed an increase in the conversion of substrate from about 1 % after 3 hours to about 14 % after 24 hours. Some of the ozonation products identified were formic acid, acetic acid, 3-methylbenzylalcohol, 3-methylbenzaldehyde and 3-methylbenzoic acid. The presence of acetic acid, ethyl acetate or acetone during ozonation significantly improved the percent conversion of m-xylene relative to similar products obtained under solvent free conditions. The presence of activated charcoal during ozonation of m-xylene showed marginal improvement in percent conversion compared to solvent free ozonation. The oxidation of 2-chloroethanol was followed by monitoring the consumption of the halogenated organic substrate which showed an increase in conversion from about 2 % after 3 hours to about 46 % after 12 hours. Ozonated products contained a mixture of acetaldehyde and acetic acid. It was also found that the ozonation of 2-chloroethanol yielded quantitative amounts of chloride ions. The percent conversion of 2-chloroethanol in the presence of acetic acid and ethyl acetate were higher than those under solvent free conditions. The use of activated charcoal during ozonolysis of 2-chloroethanol showed a significant increase in percent conversion of the substrate. Since 2-chloroethanol has a higher solubility in water than m-xylene the effects of solution pH, activated charcoal and hydrogen peroxide on ozone initiated reactions were studied. Solutions of 2-chloroethanol maintained at pH level 4 and 7 showed marginal changes in percent conversion compared to ozonation alone, however percent conversion improved significantly when the pH of the solution was increased to 10. The ozonation of 2-chloroethanol in the presence of 5 % hydrogen peroxide in water at pH levels 4 and 7 showed marginal changes in percent conversion compared to ozonation alone, however, percent conversion and product yields improved significantly, when the pH of the solution was increased to 10. Increasing the strength of the hydrogen peroxide in the reaction mixture from 5 % to 10 % had very little effect in the percent conversion of 2-chloroethanol and product formation. Based on the experimental findings the overall reaction mechanism for the reaction of both m-xylene and 2-chloroethanol with ozone is described. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.

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.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 154-159). Also available on the Internet.

The influence of dissolved natural organic matter (NOM) on the transport of Cu(II) in saturated media was investigated in controlled batch and column experiments. Six sources of natural organic matter (two in their ambient solution matrices and four isolated humic substances) were chosen to represent different environments and different humic fractions. 5i02 and a-Al203 comprised the mineral surfaces with which the NOM and Cu(II) interacted. The experiments were conducted at a constant ionic strength and buffer concentration and at pH 6.2 (all sources) and pH 7.5 (two sources). Equilibrium Cu(II) concentrations were monitored with an ion specific electrode and atomic absorption spectrophotometer and NOM was measured as UV absorbance at 254 rim. Adsorbate effect on particle surface charge was evaluated using microelectrophoresis and the effect of molecular weight on NOM breakthrough was determined with ultrafiltration of column influent and effluent. Column studies showed significant variation in NOM breakthrough as a function of source on a mixed bed of SiO₂ and a-Al203. Humic acid from the Suwannee River showed greater adsorption than the fulvic acid from the same source. The presence of Cu(II) resulted in greater retardation of all the NOM sources than in the Cu(II) free systems. Cu(II) transport was slightly facilitated at pH 6.2 by the Orange County NOM and Biscayne aquifer NOM, while the other NOM sources inhibited Cu(II) movement. At pH 7.5 the Orange County and Biscayne Aquifer sources greatly facilitated the transport of Cu(II) in a mixed bed column. The results of this research suggest that the following mechanisms can influence trace metal transport in saturated media: 1) competition of the NOM with the mineral surface for metal complexation; 2) formation of mixed ligand complexes (metal-NOM-mineral surface); 3) complexation of Cu(II) by adsorbed NOM; and 4) metal bridging of NOM to a mineral surface. The results also show that cations commonly found in natural waters ,especially Ca(II) and Mg(II), can influence the interaction of trace metals and NOM with mineral surfaces.

Research Project Technical Completion Report, Project No. G828-24, Prepared for the U.S. Department of the Interior, September 1984. / / With the growing problem of ground water contamination by volatile organic substances, drinking water sampling programs are being initiated throughout the United States. A need was recognized for a manual on well water sampling that would bridge the gap between highly technical documents and over -simplified reviews. A primer was therefore developed on establishing and implementing a sampling program. Current information was collected by means of both library research and extensive contact with public agency employees and practicing hydrologists. Portions of a sampling program that required explanation included selection of priority wells, proper sampling at the well head, sample preservation and shipment, chain of custody procedures, laboratory selection, quality assurance and data evaluation. Explanation of these steps is intended to help ensure the legal defensibility of any collected data.

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