Pharmaceutical compounds comprise a wide range of substances that are consumed in large quantities by modern societies and are generally released into local sewer networks through excretion. This research aimed to identify the factors affecting the removal efficiencies of these compounds in biological wastewater treatment plants (WWTPs) under different environmental conditions. Of the pharmaceutical compounds selected for this study, the highest influent concentrations measured in municipal wastewater treatment plants (MWWTPs) were for paracetamol, naproxen and bezafibrate (> 1 μg/L), followed by carbamazepine, atenolol, lidocaine, sulfamethoxazole and NACS (<1 μg/L). In hospital wastewater treatment plants (HWWTPs), the highest concentrations measured were for paracetamol and caffeine (> 10 μg/L), followed by ciprofloxacin and NACS (1–6 μg/L), and finally bezafibrate, carbamazepine, atenolol, lidocaine, clarithromycin and sulfamethoxazole (< 1μg/L). Antibiotic drugs were detected in HWWTPs, but rarely detected in MWWTPs. In general, the hospital wastewaters contained relatively higher levels of pharmaceuticals than municipal wastewaters. The removal efficiencies of the pharmaceutical compounds ranged widely. This was found to be related to characteristics and operational parameters of the individual WWTPs. The MWWTPs that utilized long aeration and biomass retention times (HRT,SRT), as evidenced by the occurrence of complete nitrification, were more efficient at removing paracetamol, naproxen, bezafibrate and atenolol, than the non-nitrifying plants with relatively shorter HRT and SRT. HWWTPs that operated under elevated ambient temperatures (> 26°C) achieved higher removal efficiencies (90%) for several compounds, including paracetamol, caffeine, sulfamethoxazole, ciprofloxacin, clarithromycin, NACS, atenolol, carbamazepine and lidocaine. In addition to the elevated ambient temperatures, elevated HRT and SRT and less dilution can lead to increased active biomass and can result in higher removal rates for the pharmaceutical compounds. Overall, the removal efficiencies of pharmaceuticals in WWTPs have been correlated to the type of treatment plant, the plants’ operational parameters (HRT, SRT), the climatic conditions (temperature and dilution effect of rainfall) and characteristics of the micropollutants (type and concentration). Aerobic and anaerobic batch biodegradation experiments were conducted to observe the removal of paracetamol, naproxen, ibuprofen and sulfamethoxazole at various SRTs. The biodegradation rates varied widely ranging from poor, to moderate, to high, depending on the SRT. Paracetamol was highly biodegradable under both aerobic and anaerobic conditions. Sulfamethoxazole was poorly biodegradable under aerobic conditions but highly biodegradable under anaerobic conditions. Relatively slow biodegradation rates were observed for ibuprofen and naproxen under both conditions; longer microbial adaptation periods for these two compounds were probably required. The most important factor affecting the removal of the compounds was the SRT. Therefore, the conclusion was drawn that combining anaerobic and aerobic systems with longer SRT and HRT could bring about significant reductions in the emissions of these contaminants into the environment via WWTPs; this is also a cost-effective option.

Abstract The objective of this work was to study the effect of adjustable process parameters on wood loss and bark removal in tumble drum debarking. The effect of capacity on the size distribution of the chips was studied in order to determine the optimal capacity for both the debarking and chipping sub-processes. The final aim was to propose a control strategy to optimise the processes by adapting their parameters according to the quality of the raw material. When the research started, earlier automation systems had focused on keeping the process alive, and economic values such as wood loss were not considered important. The process is usually controlled manually and shifts have different ways to manage it, which are based on trial and error. Bark removal in chemical pulp mills is usually higher than the values recommended in the literature, which in turn causes log breaking in the drum and increases wood loss. Even a small reduction in wood loss could have a substantial financial outcome. The lack of raw materials some time ago and the recession nowadays have highlighted the importance of more efficient log use. Data survey techniques were employed to reveal the interactions between drum variables from noisy measurements. Wood room data were analysed by modelling and deriving conclusions from the resulting parameters. In addition, log breaking and the size distribution of the chips were analysed under different process conditions. A pilot-scale drum was used to study residence time and the mechanical abrasion of logs. The results of this work indicated that the ratio of the volume of logs in the drum to capacity determines the residence time of the logs in the drum. Other variables influence the volume of logs in the drum, which together with capacity determine the residence time of logs in the drum, which affects wood loss and bark removal. The effect of capacity on the size distribution of the chips was not unambiguous, however, and it was therefore recommended to operate wood room at high capacity, because this reduces wood loss and increases annual production. The proposed control strategy adapts the residence time of logs in the drum to the quality of the debarked raw material by controlling the position of the closing gate. In addition, the control strategy adjusts the rotating speed of the drum using an open loop control. The results can be used to optimise the wood room process parameters. If the problem in wood room is excessive debarking, the residence time of the logs can be reduced and the rotating speed of the drum lowered. In this way the logs will be damaged less and wood loss will be reduced. Bark removal requirements in mechanical pulp mills are high, and the process parameters can be adapted to avoid problems in the subsequent processes due to excessive bark.

Master of Science / Department of Mechanical and Nuclear Engineering / Bruce R. Babin / A Surface Tension Element (STE), device was successfully constructed and tested as the primary moisture removal device in a condensing dryer. The STE was tested via the SAE ARP901 bubble-point test method and resulted in an average micron rating of 46.8 microns. The operation of the STE was compared to that of the typical air-to-air heat exchanger/condenser used in condensing dryers. The total power consumption and IEC efficiency of each case were averaged and compared. The results indicated that the STE used an average of 0.616 kilowatt-hours per kilogram dry laundry while the air-to-air heat exchanger/condenser used an average of 0.643 kWh/kg. This resulted in an improvement of the European efficiency label from class C to Class B. An analytical model was also constructed that well predicted the operation of the STE under steady state conditions.

M.Sc. / Millions of inhabitants worldwide are exposed to arsenic contaminated drinking water as a result of natural and man-made processes. Arsenic especially its inorganic forms, arsenic (III) and arsenic (V) have negative effects on human health especially in developing countries. Therefore fabricating low cost and efficient adsorbents for arsenic (III) removal is of great importance. The aim of this study is to use magnetite (Fe3O4) as filler, incorporated into a polymer blend forming composites as adsorbents for arsenic (III) removal. This work presents the fabrication, characterization and application of Fe3O4-EVA/PCL composites for arsenic (III) removal from water. Fe3O4/Ethylene-vinyl acetate copolymer (EVA)/polyaniline (PANI) and Fe3O4/Ethylene-vinyl acetate copolymer (EVA)/polycaprolactone (PCL) nanocomposites have been successfully synthesized by melt blending technique using a laboratory mixer (Thermo Scientific Haake Rheomex OS). The composites were characterized using scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques. Thermal analysis was done by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and mechanical properties using INSTRON 4443 mechanical Tester. Ability of [EVA (70%) PCL (15%) Fe3O4 (15%)] composites to adsorbed As(III) from water has been investigated through batch experiments. The maximum adsorption was 2.83 mg/g of As(III) ions at 26 ±1°C and pH 8.6. Adsorption data were fitted to Langmuir, Freundlich and Dubinin-Radushkevich isotherms. The process fits well with the Langmuir isotherm. As(III) obeyed pseudo-second order kinetics. The nanocomposites investigated in this study showed good potential for As(III) removal from contaminated water may be due to the dispersion of the magnetite nanoparticles into the polymer blend composites which increases the surface area for the adsorption.

M.Sc. (Chemistry) / The quality of fresh water is deteriorating due to pollution by a wide range of substances as a result of industrial, agricultural, domestic, mining and other anthropogenic activities. Even at trace levels in water, some pollutants are toxic to organisms through acute or chronic effects or through bioaccumulation. Conventional water treatment is often ineffective at removing pollutants to the ultra-low levels required by water quality standards and other technologies employed to remove toxic compounds from water have high capital and operating costs and other disadvantages. There is therefore an ongoing need to develop low-cost technologies that are effective for the removal of toxic pollutants from water. In our laboratories, iron and nickel (Fe/Ni) decorated carbon nanotube (CNT)/cyclodextrin polymers (β-CDs) showed promising results in previous studies carried out for the degradation and removal of toxic organic pollutants in water. However, the powder form of the polymer makes its direct application in water treatment difficult. The leaching of metal nanoparticles and carbon nanotubes from the polymer into the water being treated is also of concern due to their potential toxicity. In this study, alginate beads were investigated as supports for two kinds of nanocomposites, Fe/Ni decorated carbon nanotubes and Fe/Ni decorated carbon nanotube/cyclodextrin polymers. Alginate beads were selected as supports to render the nanocomposites more conducive towards water treatment applications since they are easy to handle and recover from water and are also stable supports that can prevent the leaching of nanomaterials into treated water.

D.Phil. (Chemistry) / Please refer to full text to view abstract

The selective recovery of rhodium from wastewaters, in which the metal would be otherwise lost, would be highly profitable if the process were suitably low-cost. Current recovery processes are generally high maintenance and high-cost, whereas biological processes can be engineered to run with little external input in terms of cost and maintenance. Three emerging technologies were chosen based on their reported efficiency when removing base metals from wastewaters. The first technology screened, the sulphide-extraction membrane bioreactor (SEMB), consists of a sulphate-reducing prokaryote (SRP) anaerobic digester, in which a silicone membrane is submerged. Wastewater is passed through the membrane and metal ions are precipitated as metal sulphides by the hydrogen sulphide gas, which is capable of permeating the membrane. The second technology screened was a fluidized sand bed reactor in which metal ions are removed from solution via induction of nucleated precipitation by sodium carbonate onto the sand grains. The third, and most well established removal technology screened was a biosorption system using immobilized Saccharomyces cerevisiae biomass as the biosorbent. Experimental trials with each technology highlighted drawbacks with each; the SEMB system proved to be largely ineffective when challenged with the removal of rhodium from the wastewater as the rhodium precipitate fouled the membrane within hours, the fluidized bed system seemed unable to overcome the acidity of the wastewater and thus could not precipitate out the rhodium metal, and the efficiency of the biosorption process was hampered by the diversity of rhodium species present in the wastewater, which reduced the amount recovered. The outcomes of the trials with each technology indicated that further optimization of the technology or pretreatment of the wastewater is necessary before any of these options can be implemented. It could be concluded, however, that despite further optimization, both the SEMB and the fluidized bed system were not applicable in this case as precipitation would be non-specific, resulting in the necessity for further steps in order to purify the rhodium ions. Hence, the biosorption system was shown to be most applicable, and further optimization of the system could yield a highly efficient rhodium recovery process.

This research was conducted to study the use of radiation in water treatment as an alternative to chlorination which has caused health concerns due to the formation of harmful disinfection by-products. Groundwater solutions from the Biscayne aquifer were radiated with Cobalt-60 gamma radiation and studied for changes in dissolved organic carbon (DOC), UV absorbance at 254 nm (UV254), fluorescence and trihalomethane formation potential (THMFP). Molecular fractionations were conducted by ultrafiltration. Effect of the combination of radiation/peroxide was studied for DOC and UV254. Radiation showed significant removal in DOC and THMFP. Similar results were seen in the fluorescence and UV absorbance experiments. Radiation/peroxide did not improve the DOC removal. Radiation of the groundwater samples broke the larger molecular weight fractions in to smaller fractions.

The objective of this research is to evaluate the influence of the factors identified by the Johnson, Kendall and Robert’s theory that affect the strength of the detachment force necessary to remove a particle of contaminant from a surface, and the roughness of the surface in which the contaminant is present, on predicting the efficiency of removal of loose contamination. Two methods were used to reach this objective: the first method consisted of quantifying the contamination by weight and the second method of quantifying the contamination by counting alpha and gamma particles. As a result, it was determined that for particles of 5 μm, the interaction between contaminant-wipe and contaminant-surface were significant. However, for particles between 37-149 μm, the contaminant-surface interaction was the only significant interaction affecting the amount of contamination removed. The results obtained were already used at a contaminated site, confirming the prediction of contamination removed

New federal regulations with regards to ammonia in wastewater effluent discharge will require over 1000 existing wastewater treatment facilities to be upgraded. Although biological treatment is the most common and economical means of wastewater ammonia removal, nitrification rates can be completely impeded at cold temperatures. Moving bed biofilm reactors (MBBR) have shown promise as an upgrade nitrifying unit at pilot-scale and full-scale applications with respect to low temperature nitrification. MBBR technologies offfer the advantages of less space requirement, utilizing the whole tank volume, no sludge recycling, and no backwashing, over other attached growth systems. Two laboratory MBBRs were used in this study to investigate MBBR nitrification rates at 20deg.C, after long-term exposure to 1deg.C, and at the kinetic threshold temperature of 5deg.C. Furthermore, the biologically produced solids from the MBBR system 20deg.C and after long-term exposure to 1deg.C, and the Arrhenius temperature correction models used to predict nitrification rates after long-term exposure to 1deg.C. The nitrification rates at 1deg.C over a four month exposure period as compared to the rate at 20deg.C were 18.7 + 5.5% and 15.7 + 4.7% for the two reactors. The nitrification rate at 5deg.C was 66.2 + 3.9% and 64.4 + 3.7% compared to the rate measured at 20deg.C for reactors 1 and 2, respectively, and as such was identified as the kinetic temperature threshold. The quantity of solids detached from the nitrifying MBBR biocarriers was low and did not vary significantly at 20deg.C and after long-term exposure to 1deg.C. Lastly, a temperature correction model based on exposure time to cold temperatures, developed by Delatolla et al. (2009) showed a strong correlation to the calculated ammonia removal rates relative to 20deg.C following a gradual acclimatization period to cold temperatures. Biofilm morphology along with biomass viability at various depths in the biofilm were investigated using variable pressure electron scanning microscope imaging (VPSEM) and confocal laser scanning microscope (CLSM) imaging in combination with viability live/dead staining. The biofilm thickness along with the number of viable cells showed significant increases after long-term exposure to 1deg.C while the dead cell coverage did not show significant increases after long-term exposure to 1deg.C while the dead cell coverage did not show significant changes. Hence, this study observed higher cell activities at warm temperatures and a slightly greater quantity of biomass with lower activities at cold temperatures in nitrifying MBBR biofilms. Using DNA sequencing analysis, 'Nitrosomonas' and 'Nitrosospira' (ammonia oxidizers)as well as 'Ntrospira' (nitrite oxidizer) were identified in which no population shift was observed during 20deg.C and after long-term exposure to 1deg.C. Furthermore, a number of non-nitrifiers were identified int he biofilm during warm and cold temperatures presenting the possibility that their presence may have provided some form of protection to the nitrifiers during long-term temperature exposure.