Ng, Tsz Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 86-98). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.vii / List of Figures --- p.xiii / List of Plates --- p.XV / List of Tables --- p.xxi / Abbreviations --- p.xxii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- "Pollution, toxicity and environmental impact of azo dye" --- p.1 / Chapter 1.2 --- Common treatment methods for dyeing effluent --- p.2 / Chapter 1.2.1 --- Physicochemical methods --- p.2 / Chapter 1.2.1.1 --- Coagulation/ flocculation --- p.2 / Chapter 1.2.1.2 --- Adsorption --- p.3 / Chapter 1.2.1.3 --- Membrane filtration --- p.4 / Chapter 1.2.1.4 --- Fenton reaction --- p.4 / Chapter 1.2.1.5 --- Ozonation --- p.5 / Chapter 1.2.1.6 --- Photocatalytic oxidation --- p.6 / Chapter 1.2.2 --- Biological treatments --- p.7 / Chapter 1.2.2.1 --- Degradation of azo dyes by bacteria --- p.8 / Chapter 1.2.2.1.1 --- Anaerobic conditions --- p.8 / Chapter 1.2.2.1.2 --- Aerobic conditions --- p.9 / Chapter 1.2.2.1.3 --- Combined anaerobic and aerobic conditions --- p.10 / Chapter 1.2.2.2 --- Decolourization of azo dyes by fungi --- p.11 / Chapter 1.2.2.3 --- Mechanisms of azo dye reduction by microorganisms --- p.12 / Chapter 1.3 --- "Chromium species, toxicity and their impacts on environment" --- p.14 / Chapter 1.4 --- Common treatment methods for chromium --- p.16 / Chapter 1.4.1 --- Chemical and physical methods --- p.16 / Chapter 1.4.2 --- Biological methods --- p.17 / Chapter 1.4.2.1 --- Chromium reduction by aerobic bacteria --- p.17 / Chapter 1.4.2.2 --- Chromium reduction by anaerobic bacteria --- p.18 / Chapter 1.5 --- Studies concerning azo dye and Cr(VI) co-treatment --- p.19 / Chapter 1.6 --- Response surface methodology --- p.21 / Chapter 1.6.1 --- Response surface methodology against one-factor-at-a-time design --- p.22 / Chapter 1.6.2 --- Phases of response surface methodology --- p.25 / Chapter 1.6.3 --- 2 - level factorial design --- p.26 / Chapter 1.6.4 --- Path of steepest ascent --- p.27 / Chapter 1.6.5 --- Central composite design --- p.28 / Chapter 2. --- Objectives --- p.30 / Chapter 3. --- Materials and Methods --- p.31 / Chapter 3.1 --- Isolation of bacterial strains --- p.31 / Chapter 3.1.2 --- Azo dye decolourization --- p.33 / Chapter 3.1.3 --- Chromate reduction --- p.34 / Chapter 3.2 --- Identification of selected bacterial strains --- p.35 / Chapter 3.2.1 --- Gram stain --- p.35 / Chapter 3.2.2 --- Sherlock® Microbial Identification System --- p.35 / Chapter 3.2.3 --- 16S ribosomal RNA sequencing --- p.37 / Chapter 3.3 --- Optimization of dye decolourization and chromate reduction efficiency with response surface methodology --- p.38 / Chapter 3.3.1 --- Minimal-run resolution V design --- p.38 / Chapter 3.3.2 --- Path of steepest ascent --- p.40 / Chapter 3.3.3 --- Central composite design --- p.41 / Chapter 3.3.4 --- Statistical analysis --- p.43 / Chapter 3.3.5 --- Experimental validation of the optimized conditions --- p.43 / Chapter 3.4 --- Determination of the performance of the selected bacterium in different conditions --- p.43 / Chapter 3.5 --- Determination of azoreductase and chromate reductase activities --- p.44 / Chapter 3.5.1 --- Preparation of cell free extract --- p.44 / Chapter 3.5.2 --- Azoreductase and chromate reductase assay --- p.45 / Chapter 3.6 --- Determination and characterization of degradation intermediates --- p.45 / Chapter 3.6.1 --- Isolation and concentration of the purple colour degradation intermediate --- p.45 / Chapter 3.6.2 --- Mass spectrometry analysis --- p.47 / Chapter 3.6.3 --- Atomic absorption spectrometry analysis --- p.48 / Chapter 4. --- Results --- p.49 / Chapter 4.1 --- Azo dye decolourizing and chromate reducing ability of the isolated bacterial strain --- p.49 / Chapter 4.2 --- Identification of selected bacterium --- p.50 / Chapter 4.3 --- Optimization of dye decolourization and chromate reduction efficiency with response surface methodology --- p.50 / Chapter 4.3.1 --- Minimal-run resolution V design --- p.50 / Chapter 4.3.2 --- Path of the steepest ascend --- p.54 / Chapter 4.3.3 --- Central composite design --- p.55 / Chapter 4.3.4 --- Validation of the predicted model --- p.62 / Chapter 4.4 --- Performance of the selected bacterium in different conditions --- p.62 / Chapter 4.4.1 --- Chromate and dichromate --- p.62 / Chapter 4.4.2 --- Initial pH --- p.63 / Chapter 4.4.3 --- Low and high salt concentration --- p.63 / Chapter 4.4.4 --- Initial K2CrO4 concentration --- p.63 / Chapter 4.4.5 --- Initial Acid Orange 7 concentration --- p.63 / Chapter 4.4.6 --- Nutrients limitation --- p.64 / Chapter 4.5 --- Chromate reductase and azoreductase activities --- p.67 / Chapter 4.6 --- Determination of degradation intermediates --- p.67 / Chapter 4.6.1 --- Mass spectrum of the degradation intermediate --- p.68 / Chapter 4.6.2 --- Chromium content of the degradation intermediate --- p.70 / Chapter 5. --- Discussion --- p.71 / Chapter 5.1 --- Characteristic of Brevibacterium linens --- p.71 / Chapter 5.2 --- Optimization of dye decolourization and chromate reduction with response surface methodology --- p.72 / Chapter 5.3 --- Performance of Brevibacterium linens under different culture conditions --- p.75 / Chapter 5.4 --- Postulation of mechanisms --- p.76 / Chapter 5.4.1 --- Possible reasons of unexpected results of the effect of initial Acid Orange 7 and K2CrO4 concentration --- p.76 / Chapter 5.4.2 --- Properties of the purple colour degradation intermediate --- p.78 / Chapter 5.4.3 --- Mechanisms likely responsible for the chromate reduction --- p.80 / Chapter 5.4.4 --- Explanation of the unexpected results --- p.80 / Chapter 6. --- Conclusions --- p.83 / Chapter 7. --- References --- p.86 / Chapter 8. --- Appendices --- p.99 / Chapter 8.1 --- Definition and calculation of different terms in 2-level factorial design --- p.99 / Chapter 8.2 --- Definition and calculation of different terms in ANOVA table --- p.100 / Chapter 8.3 --- Aliases of terms and resolution --- p.103 / Chapter 8.4 --- Moving of factors in path of steepest ascent --- p.105 / Chapter 8.5 --- Estimation of the parameters in linear regression models --- p.106 / Chapter 8.6 --- Definition and calculation of different terms in test of fitness --- p.109

Cai, Qinhong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 142-166). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / Table of contents --- p.viii / List of figures --- p.xv / List of plates --- p.xix / List of tables --- p.xxi / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Pollution generated from dyeing industry --- p.1 / Chapter 1.2 --- Occurrence and pollution of chromium azo dyes --- p.2 / Chapter 1.3 --- Common treatment methods for dyeing effluents --- p.7 / Chapter 1.3.1 --- Physicochemical methods --- p.7 / Chapter 1.3.2 --- Chemical methods --- p.9 / Chapter 1.3.2.1 --- Ozonation --- p.10 / Chapter 1.3.2.2 --- Fenton reaction --- p.11 / Chapter 1.3.2.3 --- Sodium hypochlorite (NaOCl) --- p.12 / Chapter 1.3.2.4 --- Photocatalytic oxidation (PCO) --- p.13 / Chapter 1.3.3 --- Physical methods --- p.14 / Chapter 1.3.3.1 --- Adsorption --- p.14 / Chapter 1.3.3.2 --- Membrane filtration --- p.15 / Chapter 1.3.4 --- Biological treatments --- p.16 / Chapter 1.3.4.1 --- Decolorization of azo dyes by bacteria --- p.16 / Chapter 1.3.4.1.1 --- Under anaerobic conditions --- p.18 / Chapter 1.3.4.1.2 --- Under anoxic conditions --- p.19 / Chapter 1.3.4.1.3 --- Under aerobic conditions --- p.21 / Chapter 1.3.4.2 --- Mechanisms of azo dye reduction by bacteria --- p.23 / Chapter 1.3.4.3 --- Decolorization of azo dyes by fungi and algae --- p.27 / Chapter 1.4 --- Chromium species and their impacts on environment --- p.27 / Chapter 1.4.1 --- Chromium toxicology and speciation --- p.28 / Chapter 1.4.2 --- Common treatment methods for chromium --- p.31 / Chapter 1.5 --- Studies concerning treatment of chromium azo dyes --- p.32 / Chapter 1.6 --- Response surface methodology (RSM) --- p.33 / Chapter 1.6.1 --- RSM vs. one factor-at-a-time (OFAT) design --- p.36 / Chapter 1.6.2 --- Phases of RSM --- p.39 / Chapter 1.6.3 --- Two level factorial design --- p.40 / Chapter 1.6.4 --- Path of steepest ascent (PSA) --- p.43 / Chapter 1.6.5 --- Central composite design (CCD) --- p.44 / Chapter 1.6.6 --- Estimation of the parameters in linear regression models --- p.45 / Chapter 1.6.7 --- Test of fitness --- p.47 / Chapter 2. --- Objectives and significance of the project --- p.49 / Chapter 3. --- Materials and methods --- p.50 / Chapter 3.1 --- Chemicals --- p.50 / Chapter 3.1.1 --- Chemicals for preparation of bacterial culture media --- p.50 / Chapter 3.1.2 --- Chemicals for identification of bacteria --- p.50 / Chapter 3.1.3 --- Chemicals for chromium speciation --- p.51 / Chapter 3.1.4 --- Chemicals for immobilization of bacterial cells --- p.52 / Chapter 3.2 --- Sludge samples --- p.53 / Chapter 3.3 --- Characterization of Acid Yellow 99 --- p.54 / Chapter 3.4 --- Monitor of azo dye decolorization --- p.55 / Chapter 3.5 --- "Isolation of bacterial strains, which can degrade Acid Yellow 99" --- p.55 / Chapter 3.6 --- Identification of selected bacterial strains --- p.58 / Chapter 3.6.1 --- Gram stain --- p.58 / Chapter 3.6.2 --- Sherlock® microbial identification system --- p.58 / Chapter 3.6.3 --- Biolog® microstation system --- p.59 / Chapter 3.6.4 --- Selection of the most effective bacterial strains --- p.59 / Chapter 3.6.5 --- 16S ribosomal RNA sequencing --- p.60 / Chapter 3.7 --- Chromium speciation with interferences of chromium organic complexes --- p.60 / Chapter 3.7.1 --- Instrumentation --- p.60 / Chapter 3.7.2 --- Column preparation --- p.61 / Chapter 3.7.3 --- Determination of percentage retained and recovery --- p.62 / Chapter 3.7.4 --- "Speciation of Cr(VI), ionic Cr(III) and chromium azo dye" --- p.63 / Chapter 3.7.4 --- Preparation of Cr(III)-organic complexes --- p.65 / Chapter 3.7.5 --- Preparation of a microbial degraded chromium azo dye sample --- p.65 / Chapter 3.8 --- Chromium distribution in a treated solution --- p.66 / Chapter 3.9 --- Distribution of AY99 in a treated solution --- p.68 / Chapter 3.10 --- Optimization of decolorization process with response surface methodology (RSM) --- p.70 / Chapter 3.10.1 --- Correlation of cell mass and cell density of selected bacteria --- p.70 / Chapter 3.10.2 --- Preliminary investigation of the optimum conditions --- p.70 / Chapter 3.10.3 --- Minimal run resolution V (MR5) design --- p.71 / Chapter 3.10.4 --- Path of steepest ascent (PSA) --- p.74 / Chapter 3.10.5 --- Central composite design (CCD) and RSM --- p.75 / Chapter 3.10.6 --- Statistical analysis --- p.76 / Chapter 3.10.7 --- Experimental validation of the optimized conditions --- p.77 / Chapter 3.11 --- Immobilization of bacterial cells --- p.77 / Chapter 3.11.1 --- Immobilization by polyvinyl alcohol (PVA) gels --- p.77 / Chapter 3.11.2 --- Immobilization by polyacrylamide gels --- p.78 / Chapter 3.11.3 --- Performance of immobilized cells and free cells --- p.79 / Chapter 3.11.5 --- Storage stabilities of immobilized cells and free cells --- p.80 / Chapter 3.12 --- Performance of a laboratory scale bioreactor --- p.80 / Chapter 3.12.1 --- Chromium distribution in the bioreactor --- p.82 / Chapter 3.12.2 --- Distribution of AY99 in the bioreactor --- p.82 / Chapter 3.12.3 --- Fourier transform infrared spectroscopy (FT-IR) analysis of suspended particles in the treated solution --- p.84 / Chapter 4. --- Results --- p.85 / Chapter 4.1 --- Characterization of AY99 --- p.85 / Chapter 4.2 --- Identification of isolated bacterial strains --- p.86 / Chapter 4.3 --- Selection of the most effective bacterial strains --- p.89 / Chapter 4.4 --- Chromium speciation with interferences of chromium organic complexes --- p.91 / Chapter 4.4.1 --- Effect of pH --- p.91 / Chapter 4.4.2 --- Speciation of Cr(VI)，ionic Cr(III) and chromium azo dye --- p.92 / Chapter 4.4.3 --- Effect of other Cr(III)-organic complexes --- p.93 / Chapter 4.4.4 --- Limit of detection --- p.94 / Chapter 4.4.5 --- Capacity of Amberlite XAD-4 resin --- p.94 / Chapter 4.4.6 --- Determination of Cr(VI) in a microbial degraded chromium azo dye solution --- p.95 / Chapter 4.5 --- Chromium distribution in a free cells treated solution --- p.95 / Chapter 4.6 --- Distribution of AY99 in free cells treated solution --- p.96 / Chapter 4.7 --- Optimization of decolorization process with RSM --- p.98 / Chapter 4.7.1 --- Correlation of cell mass and cell density of selected bacteria --- p.98 / Chapter 4.7.2 --- MR5 design --- p.100 / Chapter 4.7.3 --- Path of steepest ascent (PSA) --- p.102 / Chapter 4.7.4 --- Central composite design (CCD) and RSM --- p.103 / Chapter 4.8 --- Immobilization of bacterial cells --- p.106 / Chapter 4.8.1 --- Performance of immobilized cells and free cells --- p.106 / Chapter 4.8.2 --- Storage stabilities of immobilized cells and free cells --- p.108 / Chapter 4.9 --- Performance of the laboratory scale bioreactor --- p.108 / Chapter 4.9.1 --- Treatment efficiencies of the bioreactor --- p.108 / Chapter 4.9.2 --- Performance stability of the bioreactor in 5 consecutive runs --- p.111 / Chapter 4.9.3 --- Chromium distribution in the bioreactor --- p.114 / Chapter 4.9.4 --- Distribution of AY99 in the bioreactor --- p.115 / Chapter 4.9.5 --- FT-IR analysis of suspended particles in the treated solution --- p.115 / Chapter 5. --- Discussion --- p.117 / Chapter 5.1 --- Chromium speciation with interferences of chromium organic complexes --- p.117 / Chapter 5.2 --- Chromium distribution --- p.117 / Chapter 5.3 --- Distribution of AY99 --- p.122 / Chapter 5.4 --- Optimization of decolorization process with RSM --- p.124 / Chapter 5.4.1 --- MR5 design --- p.124 / Chapter 5.4.2 --- Path of steepest ascent (PSA) --- p.125 / Chapter 5.4.3 --- Central composite design (CCD) and RSM --- p.126 / Chapter 5.5 --- Immobilization of bacterial cells --- p.126 / Chapter 5.5.1 --- Performance of immobilized cells and free cells --- p.126 / Chapter 5.5.2 --- Storage stability of immobilized cells and free cells --- p.128 / Chapter 5.6 --- Performance of the laboratory scale bioreactor --- p.130 / Chapter 5.6.1 --- Treatment efficiencies of the bioreactor --- p.130 / Chapter 5.6.2 --- Performance stability of the bioreactor in 5 consecutive runs --- p.131 / Chapter 5.6.3 --- FT-IR analysis of suspended particles in the treated solution --- p.132 / Chapter 5.6.4 --- Post treatments of bioreactor treated effluents / Chapter 6. --- Conclusions --- p.136 / Chapter 7. --- References --- p.142

So, Wai Man. / Thesis submitted in: October 2007. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 112-124). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.vi / List of Figures --- p.x / List of Plates --- p.viii / List of Tables X --- p.v / Abbreviations --- p.xvii / Equations --- p.xix / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Importance of water disinfection --- p.1 / Chapter 1.2 --- Conventional disinfection methods --- p.2 / Chapter 1.2.1 --- Chlorination --- p.2 / Chapter 1.2.2 --- Ozonation --- p.3 / Chapter 1.2.3 --- Ultraviolet-C (UV-C) irradiation --- p.4 / Chapter 1.2.4 --- Sunlight irradiation --- p.5 / Chapter 1.2.5 --- Others --- p.6 / Chapter 1.3 --- Photocatalytic oxidation --- p.7 / Chapter 1.3.1 --- Reactions in PCO --- p.8 / Chapter 1.3.2 --- Disinfection mechanism of PCO --- p.11 / Chapter 1.3.3 --- Photocatalysts --- p.14 / Chapter 1.3.3.1 --- Titanium dioxide (TiO2) --- p.14 / Chapter 1.3.3.2 --- Modification of TiO2 --- p.15 / Chapter 1.3.3.2.1 --- Sulphur cation-doped TiO2 (S-TiO2) --- p.17 / Chapter 1.3.3.2.2 --- Copper(I) oxide-sensitized P-25 (Cu20/P-25) --- p.18 / Chapter 1.3.3.2.3 --- Silicon dioxide-doped TiO2 (SiO2-TiO2) --- p.18 / Chapter 1.3.3.2.4 --- Nitrogen-doped TiO2 (N-TiO2) --- p.19 / Chapter 1.4 --- Bacterial defense systems against oxidative stress --- p.20 / Chapter 1.5 --- Bacterial species --- p.22 / Chapter 1.5.1 --- Salmonella typhimurium --- p.23 / Chapter 1.5.2 --- Klebsiella pneumoniae --- p.24 / Chapter 1.5.3 --- Bacillus thuringiensis --- p.25 / Chapter 1.5.3 --- Bacillus pasteurii --- p.26 / Chapter 2. --- Objectives --- p.27 / Chapter 3. --- Material and Methods --- p.28 / Chapter 3.1 --- Culture media and diluents --- p.28 / Chapter 3.2 --- Screening of target bacteria --- p.28 / Chapter 3.3 --- PCO disinfection reaction --- p.29 / Chapter 3.3.1 --- Photocatalysts --- p.29 / Chapter 3.3.2 --- Bacterial cultures --- p.31 / Chapter 3.3.3 --- PCO reactor --- p.32 / Chapter 3.3.4 --- PCO efficacy test --- p.34 / Chapter 3.3.5 --- Comparison of different photocatalysts --- p.35 / Chapter 3.4 --- Optimization of PCO disinfection conditions --- p.35 / Chapter 3.5 --- Transmission electron microscopy (TEM) --- p.39 / Chapter 3.6 --- Superoxide dismutase (SOD) activity assay --- p.42 / Chapter 3.7 --- Catalase (CAT) activity assay --- p.44 / Chapter 3.8 --- Spore staining --- p.45 / Chapter 3.9 --- Atomic absorption spectrophotometry (AAS) --- p.45 / Chapter 3.10 --- X-ray photoelectron spectrometry (XPS) --- p.46 / Chapter 4. --- Results --- p.47 / Chapter 4.1 --- Screening of wastewater bacteria --- p.47 / Chapter 4.2 --- PCO efficacy test --- p.49 / Chapter 4.3 --- PCO under visible light irradiation --- p.53 / Chapter 4.3.1 --- Fluorescence lamps with UV filter --- p.53 / Chapter 4.3.2 --- Solar lamp with UV filter --- p.61 / Chapter 4.3.3 --- Sunlight with UV filter --- p.67 / Chapter 4.4 --- Optimization of PCO disinfection conditions --- p.75 / Chapter 4.4.1 --- Effect of visible light intensities --- p.75 / Chapter 4.4.2 --- Effect of photocatalyst concentrations --- p.77 / Chapter 4.4.3 --- Optimized conditions --- p.79 / Chapter 4.5 --- Transmission electron microscopy (TEM) --- p.79 / Chapter 4.6 --- Superoxide dismutase (SOD) activity assay --- p.83 / Chapter 4.7 --- Catalase (CAT) activity assay --- p.84 / Chapter 4.8 --- Spore staining --- p.85 / Chapter 4.9 --- Studies on Cu20/P-25 --- p.88 / Chapter 4.9.1 --- Atomic absorption spectrophotometry (AAS) --- p.88 / Chapter 4.9.2 --- X-ray photoelectron spectrometry (XPS) --- p.88 / Chapter 5. --- Discussion --- p.90 / Chapter 5.1 --- Screening of wastewater bacteria --- p.90 / Chapter 5.2 --- PCO efficacy test --- p.90 / Chapter 5.3 --- Comparison between different light sources --- p.90 / Chapter 5.4 --- Comparison between different photocatalysts --- p.93 / Chapter 5.5 --- Optimization of PCO disinfection conditions --- p.95 / Chapter 5.5.1 --- Effect of visible light intensities --- p.95 / Chapter 5.5.2 --- Effect of photocatalyst concentrations --- p.96 / Chapter 5.6 --- Transmission electron microscopy (TEM) --- p.97 / Chapter 5.7 --- Comparison between different bacterial species --- p.99 / Chapter 5.8 --- Possible factors affecting susceptibility of bacteria towards PCO --- p.99 / Chapter 5.8.1 --- Formation of endospores --- p.99 / Chapter 5.8.2 --- Differences in cell wall structure --- p.100 / Chapter 5.8.3 --- SOD and CAT activities --- p.101 / Chapter 5.9 --- Dark control of Cu20/P-25 --- p.103 / Chapter 5.10 --- Studies on Cu20/P-25 --- p.104 / Chapter 6. --- Conclusion --- p.107 / Chapter 7. --- References --- p.112 / Chapter 8. --- Appendix --- p.125 / Chapter 8.1 --- Production of S-Ti02 --- p.125 / Chapter 8.2 --- Production of Si02-Ti02 --- p.125 / Chapter 8.3 --- Production of N-Ti02 --- p.125

Deviations from ideal flow and settling occur in circular wastewater treatment tanks because of tank geometry, flow conditions, and density currents caused by variations in suspended solids concentration and temperature distributions. Thermally induced density currents were investigated in this study. Under winter, low flow conditions, measurements were made of vertical and radial temperature distributions in the circular chlorination tank at Lake Oswego, Or., and in the circular primary and secondary clarifiers at Bend, Or. Thermistor arrays were used to collect the data which exhibited both vertically well-mixed and a two-layer flow regime. Inlet geometry and suspended solids in the secondary clarifiers caused a warm bottom inflow and apparent thermal instability. Meteorological measurements were also made. The calculated winter heat loss values indicated that convective mixing may have inhibited particle sedimentation in the clarifiers.

This thesis is concerned with the use of natural waste materials, specifically used tea leaves and coffee grounds, as adsorbents for the removal of trace metals from water, e.g. in waste water treatment. Trace metals such as lead, mercury, zinc, copper, nickel and cadmium are released to the environment in waste water as a result of human activities, and generate concern because of their potential toxicity, persistence and tendency to become concentrated in food chains. While there are many conventional methods for removing these metals from waste water, such as chemical precipitation, ion exchange, membrane technologies and electrochemical treatment, these processes can be expensive. Thus in recent years there has been increasing interest in low cost adsorbent materials as alternative adsorbents, particularly waste natural products such as rice hulls and spent coffee grounds. Most of the research reported in this thesis has been conducted with spent coffee grounds, both grounds produced by leaching of commercial ground coffee and spent grounds obtained from the manufacture of instant coffee. However, some preliminary work was also conducted using spent tea leaves. In the initial work, the adsorption of the metal ions Cu�⁺, Zn�⁺, Cd�⁺ and Pb�⁺ by these adsorbents was investigated using batch adsorption methods to determine the effects of pH, metal ion concentration, adsorbent concentration and other factors such as temperature and metal ion competition. The competitive effects of soluble material leached from the adsorbents that also bind metal ions were studied. The adsorption of the metal ions was found to follow the Langmuir adsorption isotherm. However, the maximum adsorption density was found to depend on the concentration of coffee adsorbent present. Further investigation indicated that this was a result of flocculation of the coffee solids, which acted to reduce the available surface area and thus the maximum density of adsorption sites. This was confirmed using a dispersant to break up the flocculated solids. Column adsorption studies showed that metal ions adsorbed by coffee grounds could be quantitatively leached in dilute acid solution without any loss of subsequent adsorption properties, thus promoting efficient re-use of the column for many adsorption cycles. The adsorbent was also found to be largely unaffected by biological degradation. A prototype waste water treatment column was used to treat tap water samples, with and without known additions of metal ions. The results showed that the grounds efficiently adsorbed trace metal contaminants at levels as low as [mu]g L⁻�. The acid base chemistry of both tea leaves and coffee grounds, and the soluble materials leached from the fresh tea and coffee, were studied using potentiometric titration. In addition the stoichiometry of H⁺ released during metal ion adsorption was also investigated. The latter results indicated that the stoichiometry of metal ion adsorption is not simple, i.e. it probably involves more than one type of adsorption site. The results of this thesis suggest that the use of waste coffee grounds shows considerable promise for the treatment of waste water containing trace metals, and provides an alternative commercial use for such exhausted coffee materials.

Fluorinated alkyl substances, which can be persistent, toxic, and bioaccumulative, have been quantitated in many densely populated and remote regions, including in air, surface waters, groundwater, and biota; however, little is known about their transport or behavior in the environment. Wastewater effluent is one of the principal routes for introducing environmental contaminants into aquatic environments. The partitioning behavior of fluorinated alkyl substances between aqueous and particulate phases is not well characterized; thus, sorption onto sludge can be a removal mechanism of fluorinated alkyl substances from the wastewater stream. This is another route into the environment if the biosolids are land-applied. In an attempt to analyze for the fluorinated alkyl substances in wastewater, known aqueous-film-forming-foam (AFFF)-laden groundwater sampled from 3 military bases was used to develop an assay using liquid chromatography (LC), electrospray ionization (ESI) tandem mass spectrometry (MS/MS). While working on the method development, fluorotelomer sulfonates were detected at Wurtsmith AFB, MI, and Tyndall AFB, FL, where total fluoroatkyl sulfonates ranged respectively from below quantitation (���0.60 ��g/L) to 182 ��g/L and from 1100 ��g/L to 14,600 ��g/L. The LC ESI-MS/MS method was modified to quantitate fluorinated alkyl sulfonates in wastewater by incorporating a htgh volume sample loop (500 ��L), which lowered detection and quantitation limits by at least a factor of 50. This method was applied to 24 h composites of influents and effluents collected from treatment plants distributed nationwide. Fluorinated alkyl substances were observed at all 10 plants sampled, and each wastewater treatment plant was found to have a unique distribution of fluorinated alkyl substances, despite similar treatment processes. In 9 out of the 10 plants sampled, at least one class of fluorinated alkyl substance exhibited significant increases in the effluent as compared to the influent levels. The high-volume-injection LC ESI-MS/MS method was also used to monitor the mass flows of perfluoroalkyl sulfonates and carboxylates through a municipal wastewater treatment plant for 10 d. The perfluoroalkyl carboxylates were overall removed by the wastewater treatment process (25-40% removal). Perfluoroalkyl sulfonates were found to increase significantly (~200%) in the final effluent, and the fluoroalkyl sulfonamide acetic acids were found to increase by approximately 500% throughout the sludge process. From this plant, significant quantities of fluorochemicals are discharged with treated wastewater and biosolids, indicating that wastewater treatment plants are point sources of fluorinated alkyl substances and must be considered when determining origins and behavior of fluorinated alkyl substances in the environment. / Graduation date: 2005

Linear alkylbenzenesulfonate (LAS) is the most widely used anionic surfactant in commercial detergent formulations. The environmental fate of LAS is of interest because of its disposal to wastewater treatment facilities and subsequent occurrence as a micropollutant in surface waters and groundwater. While LAS fate in wastewater treatment systems and surface waters is well-documented, few studies describe LAS fate in groundwater. This work investigates the transport and biodegradation of LAS in sewage-contaminated groundwater using natural-gradient pulsed and continuous field tracer tests and laboratory column experiments. An "in-vial" disk elution technique that couples solid phase extraction disk elution of LAS as tetrabutylammonium ion pairs with injection-port derivatization was developed for the determination of LAS in groundwater. Pulsed tracer tests then were conducted in an aerobic (~9 mg/L dissolved oxygen) uncontaminated zone, and a moderately aerobic (~1 mg/L dissolved oxygen), sewage-contaminated zone. A continuous injection test also was conducted in the sewage-contaminated zone. Chromatographic separation of the surfactant mixture was observed and attributed to the greater retardation of the longer alkyl chain homologs during transport. In the sewage-contaminated groundwater, biodegradation preferentially removed the longer alkyl chain homologs and external isomers resulting in LAS mixtures that were enriched in the more mobile and biologically-resistant components. LAS mass removal coincided with a decrease in dissolved oxygen concentrations, the appearance of LAS metabolites, and an increase in the number of free-living bacteria. The composition of the LAS mixture changed in the continuous field and column experiments and biodegradation rates increased as dissolved oxygen concentration increased. Mass removal rates were generally 2-3 times greater in the column experiments than in the field for similar dissolved oxygen concentrations. Rate constants for the continuous and pulsed tests conducted in the field were comparable indicating that increased exposure time of the aquifer sediments to the LAS did not increase biodegradation rates. / Graduation date: 1998

This project explored the feasibility of using fungi in a constructed wetland for the treatment of pulp mill effluent. The effluent is high in dissolved lignins (some of which are chlorinated), which have proven very difficult to degrade biologically. Mindful of work done with the (terrestrial) white rot fungi, especially Phanerochaete chtysosporium, the question is asked, Is there a fungus which can tolerate submerged conditions while degrading a significant amount of dissolved lignins? Two fungal species with lignin-degrading capability were isolated from submerged films in a log pond. These fungi have been evaluated for decolorization potential under different environmental conditions. Results of laboratory experiments show that one of these fungi, identified as Acremonium sp., was capable of 44% decolorization of pulp mill effluent under sterile, submerged, room temperature conditions. The fungal decolorization was evaluated both in floating cultures and as a film inoculated on wood chips. In addition, bench-scale examination of the potential of this fungus to decolorize pulp mill effluent in non-sterile conditions was completed. / Graduation date: 1994

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy