A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in Partial Fulfilment of the requirements for the degree of Masters of Science in Engineering, 2017 / Access to good quality drinking water is essential for the maintenance of public health. To guarantee a steady supply of good quality water, water treatments plants are designed to provide potable water that meets national and, where necessary, local water quality standards. While the protection of natural water resources against pollution, and proper treatment of water at treatment plants are both crucial to the provision of safe drinking water, the reality is that the quality of treated water can degrade during distribution. Microbial proliferation within distribution systems can cause problems such as unpleasant tastes and odours as well as the proliferation of pathogenic microorganisms. For most utilities, it is biofilm that grows on pipe surfaces that act as permanent inocula continuously inoculating the bulk water as it flows through the distribution system. Distribution system biofilm growth and the resulting impact on water quality can be minimized by various treatment processes, designed to remove biodegradable organic matter (BOM) from the water. The removal of BOM is of great importance to water utilities because it eliminates bacterial regrowth and the many associated water quality issues. Hence, the spatial and temporal mapping of biodegradable organic carbon (BDOC) offers water utilities an effective strategy in managing the BOM in the distribution system. This research is aimed at evaluating the applicability of BOM measurement protocols to monitoring biostability and biofilm formation potential within a drinking water distribution system (DWDS). This study specifically investigated the efficacy of a simplified version of the high-density BDOC test as a protocol for monitoring BDOC in finished water. The high-density BDOC protocol was found to be a more streamlined approach in contrast to the assimilable organic carbon (AOC), and provides a suitable monitoring mechanism for lowering biofilm formation potential in DWDSs. / CK2018

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016. / Poultry slaughterhouse wastewater (PSW) contains organic matter that can be degraded by microorganisms. Such matter can further be used by the microbial community as a nutrient source for growth. Moreover, this type of wastewater also contains a high quantity of particulate matter, lipids and proteins, including antimicrobial compounds such as triclosan (TCS) and trichlorocarbanilide (TCC) used during cleaning and sanitising of processing facilities. Lipids and particulate matter lead to clogging of pipes and fouling of diffusers in the wastewater treatment plants (WWTPs). To overcome this problem, a pre-treatment system such as a dissolved air flotation system (DAFs) in which synthetic flocculants are used, is commonly used prior to the biological treatment of the wastewater. Synthetic flocculants add to the environmental burden associated with the use of synthetic compounds, particularly when these compounds are used in WWTPs. This study focused on the reduction of suspended solids, lipids and proteinaceous matter using a bioflocculant- supported DAF for the treatment of PSW.

M.Sc. / The contamination of water by toxic compounds is one of the most serious environmental problems today. These toxic compounds mostly originate from industrial effluents, agriculture runoff, natural sources (e.g. heavy metals in water from rocks and soil erosion) and human waste. The contamination, which is both “organic” and “inorganic” has an impact on the environment and human health. The demand for water and the pressure to re-use this valuable resource has increased the need for improved techniques and materials to remove pollutants from water. The Nanomaterials Science research group at the University of Johannesburg has focused on developing synthetic polymers that can be employed in water treatment and pollutant monitoring. Recently, cyclodextrins (CD) and carbon nanotubes (CNTs) have been included in polymers for this application. For example, CD-co-hexamethylene-/toluene-diisocyanate polyurethanes and CNT-modified equivalents have been developed and have been successfully applied in removing organic contaminants from water to very low levels.1 Calixarenes are synthetic analogues of cyclodextrins that can be exploited via chemical modification to express a range of properties. In the present study, calixarenes, thiacalixarenes and carbon nanotube-based polymeric materials incorporating these molecules have been synthesised, characterised and tested for removing both organic pollutants (such as p-nitrophenol) and inorganic pollutants (Cd2+, Pb2+) from water. Lead(II) and Cadmium(II) are a threat in South Africa because of their toxicity, and while p-nitrophenol is much less of a problem it represents a useful model organic pollutant. The absorption capacity of the polymers towards heavy metals and organic contaminants was tested by mixing the polymer with synthetic water containing known concentration of the contaminants at about 10 mg/L. Atomic absorption spectrometry (AAS) and ultraviolet-visible spectrometry (UV-vis) were used to determine the levels of heavy metals and organic contaminants, respectively. The target pollutants (Cd2+, 1 see KL Salipira MTech dissertation, University of Johannesburg 2008 Pb2+ and p-nitrophenol) were all successfully removed from water by the various polymers, however the degree of removal and loading capacities of the polymers differed. This information gives some insight into what functional components are needed for making successful adsorbents. It was observed, for example, that ptert- butylcalix[8]arene/hexamethylene diisocyanate (C8A/HMDI) had a higher adsorption capacity towards p-nitrophenol and Pb2+ than towards Cd2+, and also a higher capacity than the corresponding calix[4]arene polymers with smaller calixarene cavities.

Manganese is a problem at the Ni River Water Treatment Plant in Spotsylvania County, Virginia. The Ni River Reservoir (the water source) is a eutrophic reservoir. In the summer, the dissolved oxygen decreases to near or zero at depths greater than two meters. As a result, soluble manganese increases to levels of nearly 6.0 mg/L at the bottom. It is released from the sediments under anaerobic conditions. Total organic carbon levels ranging from 4.0 to 7.25 mg/L were noted with increasing depth. Plant profiles were developed to indicate the performance of the sedimentation and filtration units in reducing manganese concentration. Essentially, all the particulate manganese was removed by sedimentation, and some removal of soluble manganese was evident. The filters removed additional soluble manganese. Soluble manganese removal probably was due to the adsorption of manganese on solid manganese dioxide in the sludge blanket and on the filter media with subsequent further oxidation. Ozone was effective at a dose of approximately 5 mg/L. Chlorine and chlorine dioxide were marginally effective as pretreatments at dosages of 5 and 2 rng/L, respectively. Potassium permanganate proved effective at dosages of 0.5 to 0.625 mg/L (1.5 to 1.9 times the theoretical requirement). Aeration proved effective in reducing levels of approximately 0.1 mg/L to below the secondary maximum contaminant level (0.05 mg/L) and, in addition, somewhat effective in reducing a concentration of nearly 2 mg/L by 31 percent. Aeration appears to be a viable means of reducing the anaerobic conditions in the reservoir that lead to the high soluble manganese concentrations. / M.S.

The possibility of the existence of an iron-organic interaction in Harwood's Mill Reservoir contributing to a problem with floe formation after chlorinating filter-applied water was investigated. Shortened filtration-cycle times resulted when the filter-applied water contained the floc. The effects of varying pH, temperature, alum dosage, and oxidant addition on organic and meta.ls removals were examined with jar tests. Ultrafiltration analyses were performed to determine with which molecular size range of organic matter the iron may have been associated. Particle-size analysis was used to further examine the chlorination phenomenon. The low iron concentrations in the raw water were removed easily under any experimental condition. Organic removal, however, was optimized by alum coagulation ( 50 mg/L) at pH 5. 5 and a preoxidant dose of 2 mg/L. Improvements in organics removal over that of the WTP suggested that poor organic removal contributed to the floe-formation problem. / M.S.

Submitted in fulfillment of the requirements of the Degree of Master of Technology: Chemistry, Durban University of Technology, 2014. / This project arose out the need for a simple method to analyse NOM on a routine basis. Water samples were obtained from the Vaal dam, which is one of the dams used by a hydroelectric power station. Analysis was preceded by separation of NOM into the humic and non-humic portions. The humic portion was separated into two fractions by employing a non-ionic resin (DAX-8) to separate humic acid from fulvic acid. High performance size exclusion chromatography (HPSEC), equipped with an Ultraviolet( UV) detector and an Evaporative Light Scattering (ELS) detector connected in series, was used to obtain molecular weight distribution information and the concentration levels of the two acids. Mixed standards of polyethylene oxide/glycol were employed to calibrate the selected column. Suwanee River humic acid standard was used as a certified reference material. The molecular weight distributions (MWDs) of the isolated fractions of humic and fulvic acids were determined with ELSD detection as weight-average (Mw), number-average (Mn) and polydispersity (ρ) of individual NOM fractions. The Mw/Mn ratio was found to be less than 1.5 in all the fractions, indicating that they have a low and narrow size fraction. An increase in Mn and Mw values, with increasing wavelength for all three humic substances (HS) examined was observed. The HS, isolated from the dam water, was found to be about the same molecular weight as the International Humic Acid Standard (IIHSS). For the fulvic acid standard, the molecular weight was estimated to be around 7500 Da. Characterization of NOM was done to assist in the identification of the species present in the water. FTIR-ATR was used to as a characterization tool to identify the functional groups in the structure of the humic and fulvic acid respectively present in the Vaal Dam. Analysis of the infrared (IR) spectra indicated that the humic acids of the Vaal dam have phenolic hydroxyl groups, hydroxyl groups, conjugated double bond of aromatic family (C=C), and free carboxyl groups. The isolation method has proved to be applicable and reliable for dam water samples and showed to successfully separate the humic substances from water and further separate the humic substances into its hydrophobic acids, namely, humic and fulvic acids. It can be concluded that the Eskom Vaal dam composes of humic substance which shows that the technique alone gives a very good indication of the characteristics of water. The HPSEC method used, equipped with UV and ELSD was able to identify the molecular weight range of NOM present in source water as it confirmed that the Eskom Vaal dam contains humic substances as humic acid and fulvic acid and these pose a health concern as they can form disinfectant byproducts in the course of water treatment with chemicals. FTIR characterization was successful as important functional groups were clearly assigned. Lastly, the use of the TOC and DOC values to calculate SUVA was also a good tool to indicate the organic content in water. It is recommended to use larger amounts of water must be processed to obtain useful quantities of the humic and fulvic acid fractions.

by Chan Hiu-wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 123-133). / Text in English; abstracts in English and Chinese. / by Chan Hiu-wai. / Acknowledgements --- p.i / Abstract --- p.ii / List of Figures --- p.x / List of Tables --- p.xiii / List of Abbreviations --- p.xv / Page / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- The chemical class: Phthalate esters --- p.1 / Chapter 1.2 --- Di(2-ethylhexyl)phthalate --- p.2 / Chapter 1.2.1 --- Characteristics of DEHP --- p.5 / Chapter 1.2.2 --- Production and applications --- p.5 / Chapter 1.2.3 --- Environmental releases and environmental fate --- p.8 / Chapter 1.2.4 --- Toxicity of DEHP --- p.8 / Chapter 1.2.4.1 --- Mammalian toxicity --- p.9 / Chapter 1.2.4.2 --- Toxicity to aquatic organisms --- p.10 / Chapter 1.2.5 --- Regulations --- p.10 / Chapter 1.3 --- Conventional technologies for DEHP removal --- p.11 / Chapter 1.3.1 --- Biodegradation --- p.11 / Chapter 1.3.2 --- Coagulation --- p.11 / Chapter 1.3.3 --- Adsorption --- p.11 / Chapter 1.4 --- Innovative technologies for DEHP removal --- p.12 / Chapter 1.4.1 --- Biosorption --- p.13 / Chapter 1.4.1.1 --- Definition of biosorption --- p.13 / Chapter 1.4.1.2 --- Mechanisms --- p.13 / Chapter 1.4.1.3 --- Selection of biosorbents --- p.17 / Chapter 1.4.1.4 --- Assessment of biosorption performance --- p.21 / Chapter a. --- Batch adsorption experiments --- p.21 / Chapter b. --- Modeling of biosorption --- p.21 / Chapter 1.4.1.5 --- Recovery of biosorbents --- p.23 / Chapter 1.4.1.6 --- Development of biosorption process --- p.23 / Chapter 1.4.1.7 --- Seaweeds as biosorbents --- p.24 / Chapter 1.4.2 --- Advanced oxidation processes --- p.27 / Chapter 1.4.3 --- Heterogeneous photocatalytic oxidation --- p.30 / Chapter 1.4.3.1 --- Photocatalyst --- p.30 / Chapter 1.4.3.2 --- General mechanisms --- p.31 / Chapter 1.4.3.3 --- Influencing parameters in PCO --- p.33 / Chapter 1.4.3.4 --- Enhanced performance by addition of hydrogen peroxide --- p.33 / Chapter 2 --- Objectives --- p.36 / Chapter 3 --- Materials and Methods --- p.38 / Chapter 3.1 --- Chemical reagents --- p.38 / Chapter 3.2 --- Biosorption of DEHP by seaweed biomass --- p.39 / Chapter 3.2.1 --- Biosorbents --- p.39 / Chapter 3.2.2 --- Determination method of DEHP --- p.39 / Chapter 3.2.3 --- Batch adsorption experiments --- p.44 / Chapter 3.2.3.1 --- Screening of potential biomass --- p.44 / Chapter 3.2.3.2 --- Characterization of beached seaweed and S. siliquastrum --- p.44 / Chapter a. --- Total organic carbon (TOC) content --- p.44 / Chapter b. --- Leaching of biomass components --- p.45 / Chapter 3.2.3.3 --- Combined effect of pH and biomass concentration --- p.45 / Chapter 3.2.3.4 --- Effect of retention time --- p.45 / Chapter 3.2.3.5 --- Effect of agitation rate --- p.45 / Chapter 3.2.3.6 --- Effect of temperature --- p.46 / Chapter 3.2.3.7 --- Effect of particle size --- p.46 / Chapter 3.2.3.8 --- Effect of DEHP concentration --- p.46 / Chapter 3.2.4 --- Recovery of adsorbed DEHP from seaweed biomass --- p.47 / Chapter 3.2.4.1 --- Screening for suitable desorbing agents --- p.47 / Chapter 3.2.4.2 --- Multiple adsorption-desorption cycles --- p.47 / Chapter 3.2.5 --- Statistical analysis --- p.43 / Chapter 3.3 --- Photocatalytic oxidation --- p.48 / Chapter 3.3.1 --- Photocatalytic reactor --- p.48 / Chapter 3.3.2 --- Optimization of reaction conditions --- p.48 / Chapter 3.3.2.1 --- Effect of reaction time --- p.48 / Chapter 3.3.2.2 --- Effect of initial pH --- p.51 / Chapter 3.3.2.3 --- Effect of Ti02 concentration --- p.51 / Chapter 3.3.2.4 --- Effect of UV intensity --- p.52 / Chapter 3.3.2.5 --- Effect of H202 concentration --- p.52 / Chapter 3.3.2.6 --- Effect of initial DEHP concentration and irradiation time --- p.52 / Chapter 3.3.2.7 --- Statistical analysis --- p.52 / Chapter 3.3.4 --- Determination of mineralization of DEHP by analyzing total Organic carbon (TOC) content --- p.53 / Chapter 3.3.5 --- Identification of intermediate products of DEHP --- p.53 / Chapter 3.3.6 --- Evaluation for the toxicity of DEHP and intermediate products --- p.53 / Chapter 3.3.6.1 --- Microtox® test --- p.53 / Chapter 3.3.6.2 --- Amphipod survival test --- p.55 / Chapter 3.4 --- Feasibility of combining biosorption and photocatalyic oxidation as an Integrated treatment for DEHP --- p.57 / Chapter 3.4.1 --- Effect of algal extract on photocatalytic oxidation of DEHP --- p.57 / Chapter 3.4.2 --- Determination of mineralization of algal extract by analyzing total organic carbon (TOC) --- p.57 / Chapter 4 --- Results --- p.58 / Chapter 4.1 --- Determination method of DEHP --- p.58 / Chapter 4.2 --- Biosorption --- p.58 / Chapter 4.2.1 --- Batch adsorption experiments --- p.58 / Chapter 4.2.1.1 --- Screening of potential biomass --- p.58 / Chapter 4.2.1.2 --- Characterization of beached seaweed and S. siliquastrum --- p.61 / Chapter a. --- Total organic carbon (TOC) content --- p.61 / Chapter b. --- Leaching properties --- p.61 / Chapter 4.2.1.3 --- Combined effect of pH and biomass concentration --- p.61 / Chapter 4.2.1.4 --- Effect of retention time --- p.74 / Chapter 4.2.1.5 --- Effect of agitation rate --- p.74 / Chapter 4.2.1.6 --- Effect of temperature --- p.74 / Chapter 4.2.1.7 --- Effect of particle size --- p.74 / Chapter 4.2.1.8 --- Effect of initial DEHP concentration: Modeling by Langmuir and Freundlich adsorptin isotherm --- p.79 / Chapter 4.2.2 --- Recovery of adsorbed DEHP by seaweed biomass --- p.84 / Chapter 4.2.2.1 --- Screening for suitable desorbing agents --- p.84 / Chapter 4.2.2.2 --- Multiple adsorption-desorption cycles --- p.84 / Chapter 4.3 --- Photocatalytic oxidation --- p.90 / Chapter 4.3.1 --- Optimization of reaction conditions --- p.90 / Chapter 4.3.1.1 --- Effect of reaction time --- p.90 / Chapter 4.3.1.2 --- Effect of initial pH --- p.90 / Chapter 4.3.1.3 --- Effect of TiO2 concentration --- p.90 / Chapter 4.3.1.4 --- Effect of UV intensity --- p.90 / Chapter 4.3.1.5 --- Effect of H2O2 concentration --- p.95 / Chapter 4.3.1.6 --- Effect of initial DEHP and irradiation time --- p.95 / Chapter 4.3.2 --- Determination of mineralization of DEHP by analyzing total organic carbon (TOC) --- p.95 / Chapter 4.3.3 --- Identification of intermediate products of DEHP --- p.95 / Chapter 4.3.4 --- Evaluation for the toxicity of DEHP and the intermediate products --- p.102 / Chapter 4.3.4.1 --- Microtox® test --- p.102 / Chapter 4.3.4.2 --- Amphipod survival test --- p.102 / Chapter 4.4 --- Feasibility of combining biosorption and photocatalytic oxidation as an integrated treatment for DEHP --- p.102 / Chapter 4.4.1 --- Effect of algal extract on photocatalytic oxidation of DEHP --- p.102 / Chapter 4.4.2 --- Determination of mineralization of algal extract by analyzing total organic carbon (TOC) --- p.103 / Chapter 5 --- Discussion --- p.108 / Chapter 5.1 --- Determination method of DEHP --- p.108 / Chapter 5.2 --- Biosorption --- p.108 / Chapter 5.2.1 --- Batch adsorption experiments --- p.108 / Chapter 5.2.1.1 --- Screening of potential biomass --- p.108 / Chapter 5.2.1.2 --- Characteristic of S. siliquastrum and beached seaweed --- p.109 / Chapter 5.2.1.3 --- Combined effect of pH and biomass concentration --- p.109 / Chapter 5.2.1.4 --- Effect of retention time --- p.111 / Chapter 5.2.1.5 --- Effect of agitation rate --- p.111 / Chapter 5.2.1.6 --- Effect of temperature --- p.111 / Chapter 5.2.1.7 --- Effect of particle size --- p.112 / Chapter 5.2.1.8 --- Effect of initial DEHP concentration: Modeling of Langmuir and Freundlich adsorption isotherms --- p.112 / Chapter 5.2.2 --- Recovery of adsorbed DEHP by seaweed biomass --- p.114 / Chapter 5.2.2.1 --- Screening for suitable desorbing agents --- p.114 / Chapter 5.2.2.2 --- Multiple adsorption-desorption cycles --- p.115 / Chapter 5.3 --- Photocatalytic oxidation --- p.115 / Chapter 5.3.1 --- Optimization of reaction conditions --- p.115 / Chapter 5.3.1.1 --- Effect of reaction time --- p.115 / Chapter 5.3.1.2 --- Effect of pH --- p.116 / Chapter 5.3.1.3 --- Effect of TiO2 concentration --- p.116 / Chapter 5.3.1.4 --- Effect of UV intensity --- p.116 / Chapter 5.3.1.5 --- Effect of H2O2 concentration --- p.117 / Chapter 5.3.1.6 --- Effect of DEHP concentration and irradiation time --- p.117 / Chapter 5.3.2 --- Determination of mineralization of DEHP by analyzing total organic carbon (TOC) --- p.117 / Chapter 5.3.3 --- Identification of intermediate products of DEHP --- p.118 / Chapter 5.3.4 --- Evaluation for the toxicity of DEHP and the intermediate products --- p.119 / Chapter 5.4 --- Feasibility of combining biosorption and photocatalytic oxidation as an integrated treatment for DEHP --- p.119 / Chapter 6 --- Conclusions --- p.121 / Chapter 7 --- References --- p.123

Current use of alcohols as neat automotive fuels or as inexpensive octane enhancers in gasoline-alcohol blends, in addition to their uses as solvents and starting materials in manufacturing, have created a concern due to the increased potential for groundwater contamination. Adsorption and water solubility are primarily responsible for separating gasoline-alcohol blend components in soils and would allow alcohols to move ahead of the remaining gasoline components (e.g., benzene). The presence of alcohols would be difficult to detect, and levels hazardous to humans or animals could be reached readily. The primary objective of this study was to investigate the use of a ¹⁴C-tracer technique for evaluation of subsurface biodegradation of groundwater contaminants. A modification of the heterotrophic activity assay, the radiorespirometric method, was employed as the ¹⁴C-tracer technique. The microorganisms used were those present in soil sampled aseptically at locations in Pennsylvania and Virginia. Both saturated and unsaturated zone soils were used. The alcohols used were methanol and tertiary-butanol. Methanol was easily degraded under both aerobic and anoxic conditions up to approximately 3000 mg/L. Tertiary-butanol was degraded very slowly under both aerobic and anoxic/anaerobic conditions, and an inhibitory concentration was not readily apparent. Tertiary-butanol was degraded at rates approximately 10² slower than methano1. The data generated in this study compare favorably with data obtained by oxygen-uptake and static-microcosm methodologies. / Master of Science / incomplete_metadata

Natural organic matter (NOM) is a diverse blend of decomposed animal and plant material found in different natural water sources. Due to its large and complex structure, NOM is difficult to both remove and characterize in water. Therefore, there is a need to separate NOM into its components before it can be characterized. The aim of this project was to fractionate NOM through a novel size exclusion chromatography (SEC) composite (poly (styrene-divinyl benzene) (PS-DVB) and Polysilsesquioxane (PSQ)) packed column. Raw and final water samples from Mid-Vaal (MV), Olifantspoort (LO), Mtwalume (MT) and Preekstoel (P) were investigated. Poly (styrene-divinyl benzene) (PS-DVB) and polysilsesquioxane were both synthesized and optimized at various temperatures, compositions and time periods. An end-capping material such as hexamethyldisilizane (HMDS) was added on the PSQ to prevent active silanol groups on the polysilsesquioxane (PSQ) from reacting with active sites of NOM (our analyte). The E-PSQ (end-capped PSQ) and PS-DVB materials were packed in eight different SPE cartridges first, before the materials could be packed in the SEC column. This packing was done to check for the best mass composition of the E-PSQ and PS-DVB. From the obtained SPE results, both the EPSQ and PS-DVB were packed in one SEC/GPC column at a ratio of 1:1 in order to form the composite hybrid material. The packed SEC column was connected to an HPLC instrument and various column efficiency tests were evaluated. The results for the test of interactions with acidic compounds implied that the column can be used for the acidic analytes such as those forming NOM composition (humic acids, fulvic acids) and the column had minimum silanol groups. For hydrophobic interactions the stationary phase strength was different to that of the commercial columns and it could selectively elute molecules based on their different masses. The steric selectivity test showed that the stationary phase could separate and distinguish between molecules with similar hydrophobicity and structure but different shapes (o-terphenyl and triphenylene). The Hydrogen bonding capacity (HBC) test showed that the column had minimum silanol groups and the end-capping was successful on the E-PSQ. After fractionation of all the water samples, the MT raw showed NOM peaks around 1.8 mins, 3.4 mins and 5.3, and the final showed NOM peaks around 1.8 mins and 5.5 mins. The Mid-Vaal (MV) raw and final samples shows NOM peaks at around 1.8 mins and 6 mins. The Preekstoel (P) final water had one NOM peak at around 1.8 mins and raw samples had two NOM peaks around 1.8 mins and 6 mins. / Chemistry / M. Sc. (Chemistry)