Use of dye sensitized photooxidation is potentially a low cost means of degrading many of the hazardous compounds found in wastewaters. This study investigated the use of methylene blue as a sensitizer to degrade ortho-, meta-, and para-cresol, carbofuran and acrylonitrile. Significant reductions were found when aqueous solutions of the cresol isomers and carbofuran were illuminated and aerated in the presence of methylene blue. An average of 78% reduction of cresol was observed in seven hours. Carbofuran showed an average percent reduction of 56% in two hours. No loss was observed when the dye was absent. Acrylonitrile was found to be volatile and was stripped from solution by aeration. / M.S.

Call number: LD2668 .T4 1984 K55 / Master of Science

The characteristics of dissolved aquatic organic matter present in four natural water sources, as well as corresponding treated waters derived from eight water treatment plants, is described. An assessment is made of the performance of direct filtration, conventional treatment, and lime softening in removing trihalomethane (THM) precursors from a diverse array of water sources. A comparison is made between conventional treatment and direct filtration in removing THM precursors from a common natural water source, the Colorado River. In addition, the effect of selected initial conditions and operating parameters on the direct filtration process are evaluated by using a synthetic water/bench-scale apparatus. Important characteristics of the organic matter, including molecular weight (MW) distribution, carboxylic acidity and humic substances content, appear to affect the removal of this organic material. As a general rule, THM reactivity or yield (ug THM/mg C) increases with MW. The <10,000 MW range was found to be the most consistent reactive fraction of aquatic organic matter. All of the various treatments preferentially removed the most reactive fraction of precursor present in each MW range. None of the various treatments proved to be very effective in removing precursor material below a MW of <500. Humic molecules, with the highest carboxylic acidity and hence highest charge density, are generally more difficult to remove by alum coagulation. All of the various treatment processes studied preferentially removed hydrophobic over hydrophilic aquatic organic matter. None of the source related conditions (fulvic acid, kaolinite, pH) nor process-related conditions (flocculation velocity gradient, mixing time, prechlorination, preozonation) evaluated under the same experimental conditions exerted a major impact upon the performance of the bench-scale direct filtration process. Larger sized particles may be easier to remove by bench-scale treatment, but removal of the smaller particles may result in better removals of organic matter as quantified by NVTOC and UV Absorbance.

Two surface water sources in the southwestern United States, Colorado River Water (CRW) and California State Project Water (SPW), were studied in bench-scale experiments examining two Trihalomethane (THM) precursor removal processes, activated carbon adsorption and ozone oxidation. Both source water contained bromide (Br-) ion leading to brominated THMs upon chlorination. Activated carbon removed THM precursors, as measured by dissolved organic carbon (DOC), while having little effect on bromide. The net result was an increase in the ratio of Br-/DOC and an increase in the relative abundance of brominated THMs. Ozone oxidized higher molecular weight precursor molecules into lower molecular weight by-products which were less reactive with chlorine. Moreover, ozonation transformed Br- to hypobromous acid (an "in-situ" oxidant), leading to an increase in the percentage of brominated THMs.

by Chan Chui Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 83-94). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / 摘要 --- p.iii / Contents --- p.iv / List of Figures --- p.ix / List of Plates --- p.xi / List of Tables --- p.xii / List of Abbreviations --- p.xiv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Di(2-ethylhexyl)phthalate (DEHP) --- p.1 / Chapter 1.1.1 --- The chemical class of DEHP: Phthalate ester --- p.1 / Chapter 1.1.2 --- Characteristics of DEHP --- p.3 / Chapter 1.1.3 --- Sources of releases and environmental concentration --- p.4 / Chapter 1.1.4 --- Persistence of DEHP --- p.5 / Chapter 1.1.5 --- Routes of exposure --- p.6 / Chapter 1.1.6 --- Toxicity of DEHP --- p.7 / Chapter 1.1.6.1 --- Acute toxicity --- p.7 / Chapter 1.1.6.2 --- Chronic toxicity --- p.8 / Chapter 1.1.6.2.1 --- Adverse effects on reproduction system --- p.8 / Chapter 1.1.6.2.2 --- Carcinogenicity --- p.9 / Chapter 1.1.6.2.3 --- Developmental toxicity --- p.9 / Chapter 1.1.6.2.4 --- Endocrine disruption --- p.10 / Chapter 1.1.6.2.5 --- Hepatotoxicity --- p.10 / Chapter 1.1.7 --- Regulations --- p.10 / Chapter 1.2 --- Treatment of DEHP --- p.11 / Chapter 1.2.1 --- Conventional treatment technologies --- p.11 / Chapter 1.2.1.1 --- Physical method --- p.11 / Chapter 1.2.1.1.1 --- Adsorption --- p.11 / Chapter 1.2.1.1.2 --- Sonolysis --- p.12 / Chapter 1.2.1.2 --- Photochemical method --- p.13 / Chapter 1.2.1.2.1 --- Photocatalytic oxidation (PCO) --- p.13 / Chapter 1.2.1.3 --- Biological method --- p.13 / Chapter 1.2.1.3.1 --- Biodegradation --- p.13 / Chapter 1.2.1.3.2 --- Sewage treatment process --- p.14 / Chapter 1.2.2 --- Integrated treatment method in the present study --- p.15 / Chapter 1.2.2.1 --- Biosorption --- p.15 / Chapter 1.2.2.1.1 --- Definition of biosorption --- p.15 / Chapter 1.2.2.1.2 --- Advantages of biosorption --- p.16 / Chapter 1.2.2.1.3 --- Chitinous materials as biosorbents --- p.16 / Chapter 1.2.2.1.4 --- Advantages of using chitinous materials as biosorbents --- p.17 / Chapter 1.2.2.1.5 --- Modeling of biosorption --- p.19 / Chapter 1.2.2.2 --- PCO --- p.21 / Chapter 1.2.2.2.1 --- Definition of PCO --- p.21 / Chapter 1.2.2.2.2 --- Mechanism of PCO --- p.23 / Chapter 1.2.2.2.3 --- Advantages of PCO --- p.25 / Chapter 2 --- Objectives --- p.27 / Chapter 3 --- Materials and methods --- p.28 / Chapter 3.1 --- Materials --- p.28 / Chapter 3.1.1 --- Adsorbate --- p.28 / Chapter 3.1.2 --- Biosorbents --- p.28 / Chapter 3.1.2.1 --- Pretreatment of biosorbents --- p.29 / Chapter 3.1.3 --- Photocatalytic reactor --- p.29 / Chapter 3.1.4 --- Photocatalyst --- p.30 / Chapter 3.1.5 --- Electron scavenger --- p.31 / Chapter 3.2 --- Methods --- p.31 / Chapter 3.2.1 --- Determination of DEHP concentration --- p.31 / Chapter 3.2.2 --- Batch biosorption experiment --- p.32 / Chapter 3.2.2.1 --- Screening of biosorbents --- p.33 / Chapter 3.2.2.2 --- Optimization of biosorption conditions --- p.33 / Chapter 3.2.2.2.1 --- Effect of biosorbent concentration --- p.33 / Chapter 3.2.2.2.2 --- Effect of initial pH --- p.33 / Chapter 3.2.2.2.3 --- Effect of biosorption time --- p.34 / Chapter 3.2.2.2.4 --- Effect of temperature --- p.34 / Chapter 3.2.2.2.5 --- Effect of agitation rate --- p.34 / Chapter 3.2.2.2.6 --- Effect of initial DEHP concentration --- p.34 / Chapter 3.2.2.2.7 --- "Combinational effect of initial pH, chitin A concentration and initial DEHP concentration" --- p.35 / Chapter 3.2.3 --- Extraction of adsorbed DEHP from chitin A --- p.35 / Chapter 3.2.3.1 --- Screening of extraction agents --- p.36 / Chapter 3.2.3.2 --- Determination of extraction time --- p.36 / Chapter 3.2.4 --- Batch PCO experiment --- p.36 / Chapter 3.2.4.1 --- Optimization of PCO conditions --- p.38 / Chapter 3.2.4.1.1 --- Effect of reaction time --- p.38 / Chapter 3.2.4.1.2 --- Effect of UV-A intensity --- p.38 / Chapter 3.2.4.1.3 --- Effect of TiO2 concentration --- p.38 / Chapter 3.2.4.1.4 --- Effect of H2O2 concentration --- p.38 / Chapter 3.2.4.1.5 --- Effect of initial pH --- p.39 / Chapter 3.2.4.1.6 --- Combinational effect of H2O2 concentration and initial pH --- p.39 / Chapter 3.2.4.1.7 --- Effect of concentration factor --- p.39 / Chapter 3.2.4.2 --- Identification of intermediates/products of DEHP --- p.39 / Chapter 3.2.4.3 --- Evaluation for the toxicity of DEHP and the intermediates/products by the Microtox® test --- p.40 / Chapter 4 --- Results --- p.42 / Chapter 4.1 --- Batch biosorption experiment --- p.42 / Chapter 4.1.1 --- Screening of biosorbents --- p.42 / Chapter 4.1.2 --- Optimization of biosorption conditions --- p.42 / Chapter 4.1.2.1 --- Effect of biosorbent concentration --- p.42 / Chapter 4.1.2.2 --- Effect of initial pH --- p.42 / Chapter 4.1.2.3 --- Effect of biosorption time --- p.46 / Chapter 4.1.2.4 --- Effect of temperature --- p.46 / Chapter 4.1.2.5 --- Effect of agitation rate --- p.46 / Chapter 4.1.2.6 --- Effect of initial DEHP concentration --- p.46 / Chapter 4.1.2.7 --- "Combinational effect of initial pH, chitin A concentration and initial DEHP concentration" --- p.51 / Chapter 4.1.2.8 --- Summary of biosorption conditions before and after optimization --- p.54 / Chapter 4.2 --- Extraction of adsorbed DEHP from chitin A --- p.54 / Chapter 4.2.1 --- Screening of extraction agents --- p.54 / Chapter 4.2.2 --- Determination of extraction time --- p.55 / Chapter 4.3 --- Batch PCO experiment --- p.56 / Chapter 4.3.1 --- Optimization of PCO conditions --- p.56 / Chapter 4.3.1.1 --- Effect of reaction time --- p.56 / Chapter 4.3.1.2 --- Effect of UV-A intensity --- p.57 / Chapter 4.3.1.3 --- Effect of TiO2 concentration --- p.59 / Chapter 4.3.1.4 --- Effect of H2O2 concentration --- p.60 / Chapter 4.3.1.5 --- Effect of initial pH --- p.61 / Chapter 4.3.1.6 --- Combinational effect of H2O2 concentration and initial pH --- p.62 / Chapter 4.3.1.7 --- Effect of CF --- p.63 / Chapter 4.3.1.8 --- Summary of PCO conditions before and after optimization --- p.63 / Chapter 4.3.2 --- Identification of intermediates/products of DEHP --- p.64 / Chapter 4.3.3 --- Evaluation for the toxicity of DEHP and the intermediates/products by the Microtox® test --- p.66 / Chapter 5 --- Discussion --- p.68 / Chapter 5.1 --- Batch biosorption experiment --- p.68 / Chapter 5.1.1 --- Screening of biosorbents --- p.68 / Chapter 5.1.2 --- Optimization of biosorption conditions --- p.69 / Chapter 5.1.2.1 --- Effect of biosorbent concentration --- p.69 / Chapter 5.1.2.2 --- Effect of initial pH --- p.69 / Chapter 5.1.2.3 --- Effect of biosorption time --- p.70 / Chapter 5.1.2.4 --- Effect of temperature --- p.71 / Chapter 5.1.2.5 --- Effect of agitation rate --- p.71 / Chapter 5.1.2.6 --- Effect of initial DEHP concentration --- p.71 / Chapter 5.1.2.7 --- "Combinational effect of initial pH, chitin A concentration and initial DEHP concentration" --- p.73 / Chapter 5.2 --- Extraction of adsorbed DEHP from chitin A --- p.74 / Chapter 5.2.1 --- Screening of extraction agents --- p.74 / Chapter 5.2.2. --- Determination of extraction time --- p.74 / Chapter 5.3 --- Batch PCO experiment --- p.74 / Chapter 5.3.1 --- Optimization of PCO conditions --- p.74 / Chapter 5.3.1.1 --- Effect of reaction time --- p.74 / Chapter 5.3.1.2 --- Effect of UV-A intensity --- p.74 / Chapter 5.3.1.3 --- Effect of TiO2 concentration --- p.75 / Chapter 5.3.1.4 --- Effect of H2O2 concentration --- p.75 / Chapter 5.3.1.5 --- Effect of initial pH --- p.76 / Chapter 5.3.1.6 --- Combinational effect of H2O2 concentration and initial pH --- p.77 / Chapter 5.3.1.7 --- Effect of CF --- p.77 / Chapter 5.3.2 --- Identification of intermediates/products of DEHP --- p.78 / Chapter 5.3.3 --- Evaluation for the toxicity of DEHP and the intermediates/products by the Microtox test --- p.79 / Chapter 6 --- Conclusions --- p.80 / Chapter 7 --- References --- p.83

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

Co-produced water from the oil and gas industry represents a significant waste stream in the United States. Produced water is characterized by high levels of total dissolved solids (TDS), dissolved organics and oil and grease. Among the wide variety of organics present in the water, the concentration of hazardous substances such as benzene, toluene, ethylbenzene, and xylenes (BTEX) can reach 600 mg/L and the concentration of non-hazardous carboxylate can be as high as 10,000 mg/L (API, 2002). Regulations governing the disposal of produced water are tightening and the interest in reusing treated produced water is increasing in the United States particularly in regions with scarce water supplies. In order to reuse produced water, removal of both the inorganic dissolved solids and hazardous organics such as BTEX may be necessary. The main goal of this research was to investigate the feasibility of using a combined physicochemical/biological treatment system to remove the organic constituents present in saline produced water. In order to meet this objective, two separate biological treatment techniques were investigated: a vapor phase biofilter (VPB) to treat the regeneration off-gas from an upstream surfactant-modified zeolite (SMZ) adsorption system and a membrane bioreactor (MBR) to treat the carboxylate and BTEX constituents that penetrate an upstream SMZ system. Each of the biological pretreatment systems was investigated first in the laboratory treating synthetic produced water and then in the field coupled to an SMZ adsorption system treating produced water. Both of the biological treatment systems were capable of removing the BTEX constituents both in the laboratory and in the field over a range of operating conditions. For the VPB, separation of the BTEX constituents from the saline aqueous phase yielded high removal efficiencies. However, carboxylates remained in the aqueous phase and were not removed in the combined VPB/SMZ system. In contrast, the MBR was capable of directly treating the saline produced water and simultaneously removing the BTEX and carboxylate constituents. The major challenge of the MBR system was controlling membrane fouling, particularly when the system was treating produced water under field conditions.

No description available.

M.Sc. / Natural Organic Matter (NOM) is a complex of organic material present in a natural surface water. Odour, taste and acidity are some of the problems associated with NOM in water systems. Futhermore, it causes the yellow or brown colour of water, whic is aesthetically unpleasant to consumers. NOM is also the energy source of bacterial re-growth and aids in the transportation of metal ions in the distribution system.Moreover, NOM in water can react with disinfectants, e.g. chlorine, to form disinfection by products (DBPs) such as trihalomethanes (THMs) and habacetic acids (HAAs). DBPs have recently been found to have adverse effects in humans. This study was undertaken in order to assess the effectiveness of some of the water treatment techniques employed by selected water supplying companies in dealing with NOM. To achive this, the water treatment processes used by these companies to reduce NOM and metal ions were coagulation, sand filtration, the use of granular activated carbon, ozonation and chlorination. In addition, β-cyclodextrin (β-CD) polyurethanes synthesized in our laboratories were used to remove the DBPs present in the water samples.

M.Sc. / With increasing industrial activities in South Africa, many of its waters are contaminated with both organic and inorganic pollutants. This is also a worldwide challenge which has resulted in an escalation in research efforts to combat it. Organic pollutants, for example, can be harmful to human health and the environment. Even when present at low concentrations, they tend to bio-accumulate and interact with endocrine systems. Therefore it is necessary that these pollutants are removed from effluents before they are integrated with water systems such as rivers and lakes. In an effort to utilize economic and efficient removal techniques, low cost and locally available materials have been used as potential adsorbents for the removal of these organic pollutants from synthetic wastewater. These coal-based materials were further fabricated into nanoporous sorbents through activation processes to improve their adsorption properties. The project reported in this dissertation was thus undertaken to explore, specifically, the efficacy of coal and coal-based sorbents (acid treated coal, activated carbon and activated fly ash) in their ability to remove phenolic compounds from wastewater.