A microwave enhanced advanced oxidation process using hydrogen peroxide (MW/H₂O₂-AOP) was used for the release of nutrients and the destruction of solids from secondary municipal sewage sludge. The significant factors affecting the MW/H₂O₂-AOP that would yield maximum soluble substrates were studied. Using a computer statistical software package for experimental design and data analysis, four factors including microwave heating temperature, heating time, hydrogen peroxide dosage, and sludge solids content, were selected and examined. The initial sludge TS content and hydrogen peroxide dosage were the most significant factors for the solubilization of COD and nutrients release under the experimental conditions selected in this study. Overall, the maximum solubilization of nutrients was obtained at 2.5 % of total solids content, 2% of hydrogen peroxide by weight, 5 min. of microwave heating and 120 ºC. The effects of combination of microwave treatment and oxidative reagents on solids destruction and nutrients release were also investigated. Microwave enhanced advanced oxidation processes (MW-AOP), such as MW/O₃, MW/H₂O₂ and MW/H₂O₂/O₃, were conducted at 100 °C. In terms of nutrients release and solids reduction, the MW/H₂O₂/O₃-AOP yielded the best result. Subsequently, three factors including microwave heating temperature, hydrogen peroxide dosage, and ozone dosage, were investigated. The best result, in terms of the release of phosphate and ammonia, and solids reduction, was obtained with additions of 2 % hydrogen peroxide by weight and ozone dosage of 5.09 mg/ml, and operating at 120ºC. About 95%, 32% and 78% of TP, TKN and COD were released into the solution, respectively. The microwave enhanced advanced oxidation processes, with and without an addition of ferrous sulfate (MW/H₂O₂-AOP and MW/H₂O₂/Fe+²-AOP), were also studied for reducing solids, and solubilizing nutrients from the secondary sewage sludge. For the MW/H₂O₂/Fe+²-AOP, the best results of solubilization, in terms of orthophosphate, ammonia and soluble chemical oxygen demand, were obtained at treatment temperatures of 40 ºC, the yields decreased as the temperature was increased. The highest yields of solubilization were obtained at 60 ºC for orthophosphate, and at 80 ºC for both ammonia and soluble chemical oxygen demand.

As human population increases, the need for water increases in domestic, agricultural, industrial and urban sectors. Wastewater reuse after treatment is gaining acceptance world wide, as availability of fresh water sources decreases. However, it is also important to point out social and cultural differences that still exist in different pars of the world including those where reuse of wastewater for food production or any domestic use is not yet acceptable. The major concerns with effluent reuse are primarily its impact on human health and environmental risk. As a result, effluent reuse should be undertaken with caution after careful consideration of the potential impacts and risks. This thesis examined the potential to use the hydroponics nutrient film technique to grow commercially important crops using secondary-treated domestic wastewater. The crops chosen were a fruit crop (Lycopersicon esculantum - tomato), a leafy crop (Beta vulgaris ssp. cicla - silver beet) and a flower crop (Dianthus caryophyllus - carnation). Secondary-treated domestic wastewater was chosen because of the reduced risk of pathogen and heavy metal contamination in the crops and due to the guideline requirements for use of treated effluent for food crops. The possibility of using the effluent after the hydroponics treatment for further irrigation was also studied. The ability of secondary-treated effluent to supply adequate nutrients to the crops was assessed relative to a commercially available hydroponics solution (Chapter 3). The amount of time the solution was left in the system (nutrient solution retention time) was dependant on the plant uptake of the solution. The results obtained showed that the nutrients in secondary treated effluent was adequate for the carnations, but not for the food crops. The food crops from both treatments were compared to the produce purchased from a supermarket. The food crops showed signs of nutrient deficiency, particularly nitrogen. Based on the findings of the first experiment, the nutrient solution retention time was amended to 14 days. The carnations were not tested with the shorter nutrient solution retention time (NSRT) because they performed well in the previous trial with the longer nutrient solution retention time. The edible food crops performed better and did not show signs of nutrient deficiency when the nutrient solution retention time was reduced to 14 days. Further statistical analysis was conducted with the data from Chapters 3 and 4. Nutrient and water balances were calculated and the possible reason that the plants grown in the 14-day nutrient solution retention time took up more water, was a result of increased nutrients and better growth. A simple model was constructed to calculate height of the plants using multiple regression. The model was validated against the data collected from this study. The experiment conducted in Chapter 6 determined the nutritional quality of the food crops. The harvests from the wastewater and commercially available hydroponics solution were compared to produce purchased from a supermarket and tested for total caroteniods, total soluble solids and ascorbic acid concentrations. The nutritional quality of the wastewater grown produce was comparable to those grown in the hydroponic solution and those purchased. The risk of pathogen contamination to food crops and the die-off of pathogens in the hydroponic channels were studied in Chapter 7. This was tested by spiking the commercial hydroponic medium with Escherichia coli and Salmonella typhimurium and monitoring bacterial pathogen die-off in the secondary treated domestic wastewater. The pathogen quality of the crop was tested in all treatments as well as on organically grown produce found at a local supermarket. The results of this experiment did not show any contamination on the surface of the food crops or within the food crops. This study demonstrated that growing tomatoes, silver beet and carnations using secondary-treated domestic wastewater was successful when the nutrient solution retention time was adjusted to the optimum level. In arid, developing and remote communities, this system is ideal as it conserves and reuses water for commercially important crops without compromising the health of the environment or of human beings. It can also be implemented in urban areas, as the system can be scaled according to the availability of space. In addition to this, the effluent after going through this system can be used for open irrigation as it meets the World Health Organisation guidelines. However, a number of additional concerns need further investigation. They include the transmission risk of other types of pathogen, which depends on the source of wastewater, and the effects of hormones and antibiotics on food crops and their effect on human health.

This study examines different governance models for urban wastewater reuse in Australia and India. The study analyses the role of different societal sectors-public, private, and the community in provision and use of wastewater for irrigation. It encompasses three case studies representing different models of governance: (1) Virginia pipeline scheme built on the BOOT model, (2) Willunga pipeline scheme built on the divesture model, and (3) Musi irrigation scheme representing the case of unsupported community wastewater reuse.

Made available in DSpace on 2014-06-11T19:32:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-15Bitstream added on 2014-06-13T19:22:43Z : No. of bitstreams: 1 urbinati_e_dr_jabo.pdf: 5886769 bytes, checksum: 63f1caa6dcd838954763a5044d4cbd37 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Avaliou-se o desempenho de doisconjuntosde reatores UASB instalados em série, notratamento de águas residuárias de suinocultura, e o reúso dos efluentes na adubação de milho e sorgo. Os conjuntos I e II foram compostos por dois reatores UASB em série com volumes de 908 e 350 L e de 908 e 188 L, respectivamente. No conjunto II foi realizado o pós-tratamento em um reator aeróbio operado em bateladas seqüenciais (RBS) de 3000 L. Os tempos de detenção hidráulica (TDH) aplicados no reator do primeiro estágio (R1) foram de 72, 54 e 42 horas em ambos os conjuntos. As cargas orgânicas volumétricas (COV) aplicadas no R1 variaram de 6,9 a 12,6 kg DQOtotal (m3 d)-1 e de 7,5 a 9,8 kg DQOtotal (m3 d)-1, dos conjuntos I e II respectivamente. Nos sistemas de tratamento anaeróbios, as eficiências médias de remoção de DQOtotal, nitrogênio Kjeldahl (NK) e fósforo total (P-total) no conjunto I atingiram 96, 68 e 64%, respectivamente, e no conjunto II, 95, 61 e 60%, respectivamente. Para Cu, Fe, Mn e Zn, as eficiências médias de remoção dos sistemas de tratamento anaeróbio, no conjunto I atingiram 94, 88, 78 e 92%, respectivamente, e no conjunto II, 82, 80, 81 e 90%, respectivamente. Com a inclusão do RBS aeróbio no sistema II, as eficiências aumentaram para valores de 98, 73 e 82% para DQOtotal, NK e P-total, respectivamente, e de 88, 91, 86, 99 e 99,3%, para Cu, Fe, Mn, Zn e coliformes termotolerantes, respectivamente. O reúso dos efluentes tratados e do dejeto bruto, não promoveu mudanças na produtividade do milho e do sorgo, porém, a aplicação dos efluentes tratados elevaram as concentrações de N prontamente disponível para as plantas no solo. Mesmo aplicados em doses muito maiores comparativamente ao dejeto bruto, os efluentes tratados promoveram menor contaminação do solo por coliformes totais e termotolerantes / The performance of two sets of UASB reactors installed in series was evaluated, for treatment of swine wastewater, and reuse of effluent as fertilizer for corn and sorghum. The sets I and II were composed of two UASB reactors in series with volumes of 908 and 350 L and 908 L and 188, respectively. In set II was performed after treatment in an aerobic reactor operated in sequencing batch mode (RBS) of 3,000 L. The hydraulic retention time (HRT) used in the first stage reactor (R1) were 72, 54 and 42 hours in both sets. The organic loading rate (OLR) applied on the R1, ranged from 6.9 to 12.6 kg total COD (m3 d)-1 and 7.5 to 9.8 kg total COD (m3 d)-1 in clusters I and II respectively. In anaerobic treatment systems, the average removal efficiencies of total COD, Kjeldahl nitrogen (NK) and total phosphorus (total P) in the set I reached 96, 68 and 64% respectively, and set II, 95, 61 and 60%, respectively. For Cu, Fe, Mn and Zn, the average removal efficiencies of anaerobic treatment systems, on the whole I reached 94, 88, 78 and 92% respectively, and set II, 82, 80, 81 and 90% respectively . With the inclusion of aerobic RBS in the set II, increased efficiencies, reaching values of 98, 73 and 82% for total COD, total-P and NK, respectively, and 88, 91, 86, 99 and 99.3% for Cu , Fe, Mn, Zn and thermotolerant coliforms, respectively. The reuse of treated effluent and raw manure, did not promote changes in the productivity of maize and sorghum, however, the application of treated effluent increased concentrations of N readily available for plants in soil. Even in much larger doses applied compared to the raw waste, the treated effluent, promoted soil contamination by total coliforms and thermotolerant considerably less

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Investigations were initially carried out to characterize the materials present in shape, mineralogical and chemical composition, and particle size distribution. A micro-electrophoresis apparatus was constructed to determine the electrokinetic parameters of the colliery waste-water. The origin of the surface charge which forms on minerals immersed in water is important in flocculation. The nature of the charges on the fines were determined to be both positive and negative. This could be due to the coating of the particles by the addition of the froth flotation reagent used. The electrophoretic mobilities of the particles were measured at the various pH values and at different depths within the electrophoretic cells. These values of the electrophoretic mobilities were used to calculate the values of the zeta potential by the application of Smoluchowski's equation. The iso-electric point (IEP) and the zero point of charge (ZPC) were also investigated and found to coincide at all the different levels of depth within the electrophoretic cell. Finally the colliery waste-water was clarified successfully by flocculating it using the polyacrylamide solution.

>Magister Scientiae - MSc / Over the last decade polysulfone membranes have been demonstrated to be one of the best membrane types in wastewater treatment, especially in ultrafiltration, owing to its mechanical robustness, structural and chemical stability. Regrettably these membranes are mostly hydrophobic by nature and therefore highly vulnerable to fouling due to chemosorptive mechanisms. Fouling may be caused by cake formation on the surface of the membrane or by surface assimilation of the foulants. Many studies have been directed at improving hydrophilic properties of polysulfone membranes by introducing different types of nanoparticle composite such as TiO2, ZnO2, Au and Ag nanoparticles to the polymer matrix, in order to reduce fouling potential and increase membrane performance. In the present investigation a hydrogel material was developed by crosslinking polyvinyl alcohol (PVA) with polysulfone (PSF), using glutaraldehyde as crosslinker. PVA has excellent film formation, emulsifying and adhesive properties, it is highly flexible and has high tensile strength. Introducing PVA into the PSF polymer matrix was expected to impart its advantageous properties onto the resulting membrane and enhance hydrophilic characteristics of the membrane. The cross linking of PVA and PSF was controlled at three different ratios to evaluate the effect of the PSF contribution i.e. 25:75, 50:50 and 75:25. The crosslinked polymer composites produced three unique hydrogel materials, which were evaluated for the separation of selected small organic molecules, under hydrodynamic conditions, using rotating disk electrochemistry. The hydrogel thin film behaved as a chemical sensor for the oxidation of tannic acid in aqueous solution, with negligible shift in peak potential as a function of concentration. The nanomaterials prepared were characterised using spectroscopic, morphological and electrochemical techniques. Hydrogel performance in the presence of analyte molecule was evaluated by hydrodynamic voltammetry and electrochemical impedance spectroscopy. From calibration curves based on cyclic voltammetry, hydrodynamic, macroscopic and spectroscopic techniques, the 75% polysulfone and 25 % polyvinyl alcohol hydrogel (75:25 PSF-PVA) presented the best performance for quantitative detection and best sensitivity toward alginic acid and tannic acid than the corresponding composites (50:50 and 25:75 PSF-PVA). Optical results (contact angle) show an agreement with spectroscopic (EC) and microscopic (AFM) result. A decrease in contact angle gives an increase in roughness and diffusion coefficient. High surface roughness was linked to improved hydrophilicity of the polysulfone.

In many biological reactors' bicarbonate ions are the major species determining pH buffering capacity, or alkalinity. In anaerobic digesters the bicarbonate levels should be within 10 to 50mM to ensure stable operation. Bicarbonate concentration in wastewater treatment processes is routinely measured off-line by titration with standard acid to a set pH value. However along with the bicarbonate/carbonate system, the phosphate, ammonia, sulphides and volatile fatty acids systems are present in anaerobic process. These systems can exert a significant influence on the accuracy of bicarbonate titration's to a set pH. An overload of 4.7 to 13.6 kgCODm-3d-1 1 administered to a 5m3 pilot scale anaerobic filter reactor showed that bicarbonate alkalinity, measured off-line by titration responded rapidly to the organic overload, decreasing by 10% after only 1 hour of the overload initiation. The propionic acid concentration (often regarded as the best indicator of instability in anaerobic digestion) increased from 170ppm to 190 ppm in the same period, which corresponds to an increase of 12%. At present the use of anaerobic digestion as a waste treatment method is partly limited because of the lack of reliable control procedures. This thesis introduces a simple on-line instrument for direct determination of bicarbonate concentration especially for automatic control of anaerobic digesters. The proposed method is based on a continuous flow rate measurement of carbon dioxide evolved from a continuous stream of sampled (<15cm3min-1 ) solution after saturation with gaseous C02 and subsequent acidification with excess acid. Measurement of bicarbonate in this way eliminates the interferences of the phosphate, ammonia, sulphides and volatile fatty acids systems and removes the need for a pH probe which are subject to fouling.