The development of sustainable and green technologies powered by renewable energy sources is highly desired to address the growing global energy need and water scarcity problems. Heterogeneous photocatalysis emerged in the past decades as promising solar-powered technology for environmental remediation applications such as wastewater treatment. The photoactivity of the materials is believed to be governed by complex mechanisms, still it was shown that it may be critically dependent on the following material properties (i) ability and effectiveness to absorb incident photons, (ii) charge separation efficiency, (iii) charge utilization efficiency, (iv) morphology including the size and shape of the nanostructure and its distribution and (v) the crystal structure, phase composition and crystallinity ... etc. Hence, most strategies aiming to improve the performance of photocatalytic materials may focus on one or more of the aforementioned aspects. Beside developing new materials or modifying existing systems, the development of sustainable, easy-to-operate systems are highly desired for developing countries such as Africa where almost half of the population are affected by water scarcity of some sort. For this motivation the immobilization of powder catalyst could be one attractive solution. In this thesis three experimental systems are presented. In the first two the effect of material properties on the photoactivity whereas in the third chapter the immobilization of powder catalyst was investigated. The first experimental project aimed to study the effect of synthesis parameters of WO3 nanostructures on its morphology, phase composition, optical properties and ultimately on the photoactivity. Understanding the role of process parameters to gain control over the material properties is still a challenge but is of great interest in photocatalysis. Here, a hydrothermal synthesis method was employed to synthesize WO3 nanostructures with various morphologies, crystal phases and optical properties. The effect of the solution pH, the polymeric surface modulator and the added EtOH was investigated on the material properties and on the photocatalytic activities. It was found that the crystal structure and the morphology of WO3 was influenced by the solution pH in the first place. It was proposed that stabilization effects between the crystal phase and the morphology could also influence the crystallization process beside supersaturation. It was revealed that despite the highest surface area of W-2.01-P20E, reduced oxidation state did not promote high photo-response. Instead the photoactivity of WO3 was seen as the compromise of the material properties including the optical, structural properties and the oxidation state. In the second experimental project the effect of Ag co-catalysis was studied on TiO2- Cu2O heterostructure formation. Coupling a wide band gap (TiO2) and a narrow band gap (Cu2O) semiconductor could benefit from extended light absorption properties and additionally from enhanced charged separation. In this study a facile wet chemical synthesis method was coupled with a UV treatment step to fabricate TiO2-Ag-CuxO ternary hybrid nano-materials. The effect of the Ag loading (1-5%) and the synthesis sequence of the Ag deposition step was evaluated on the material properties as well as on the visible photocatalytic activity. It was revealed that both the amount and the order of the Ag-deposition altered the material properties considerably. Typically TiO2/CuxO/Ag (TCA) catalysts had better visible light absorption properties but reduced affinity to adsorb methyl orange (MO) to their surface. Whereas, TiO2/Ag/CuxO (TAC) catalysts in general had better dye adsorption properties relative to TCA and had more efficient decoloration properties under visible light. TOC and HPLC-MS analysis revealed that MO and possibly its degradation products were mainly mineralized and/or adsorbed to the surface of TAC catalyst with 5% nominal Ag content in the visible process generating limited amount of byproducts in the final solution. The third experimental project focused on the immobilization of the previously prepared powder TiO2-Cu2O nanostructure. In this work a fluorine-doped tin oxide (FTO) glass sheet was used as a substrate and the doctor-blade coating technique has been employed to make TiO2-Cu2O thin films. Although this technique has a widespread use in the fabrication of solar cells to the best of our knowledge this is the first report on supported TiO2-Cu2O photocatalytic systems prepared by this method. To optimize the performance of the TiO2- Cu2O thin film under visible light irradiation, the chemical composition of the doctor-blading paste and the temperature of the final thermal treatment step was studied. It was found that both the paste composition and the heat treatment step played an important role in the material properties. When the film contained ethyl cellulose the minimum temperature to remove organic additives was 350 °C. Whereas for the films containing only alpha terpineol 300 °C was sufficient. It was revealed that the higher temperature treatment resulted in more oxidized films which were also shown in their deeper colour. The most effective film under visible light irradiation was TC-0-300 which contained no cellulose and was treated at the lowest temperature.

Driven by the rising costs, decreasing convenience, and increased demand of fossil fuels, the need for alternative, sustainable energy sources has caused a spark in interest in biomass-based fuels. Oleaginous organisms such as yeast, algae, and bacteria have been considered as microscopic biofactories for oils that can be converted into biodiesel. The process of growing such organisms using current technology requires an alarming amount of freshwater, which is another resource of growing concern. The research detailed within explains how several sources of underutilized wastewater can serve as growth medium in the biodiesel production process. Using only nitrogen and in one case phosphorus as external supplements, algae were shown to grow on produced water from oil and gas industry waste, local municipal wastewater, environmental brackish water from the Great Salt Lake, and wastewater from the potato processing industry. In each case, growth and biodiesel production in wastewaters was as good as or better than laboratory media. The bacterial organism Rhodococcus opacus PD630 and the yeast organism Cryptococcus curvatus were also used to grow on the dairy manufacturing wastewater whey permeate, a large source of underutilized fixed carbon, with successful lipid production. C. curvatus was also used to successfully grow and form large amounts of biodiesel from ice cream factory wastewater and from wheat straw hydrolysate. In each case, the need for freshwater and outside nutrients was nearly entirely replaced, with the exception of some nitrogen supplementation, with a wastewater nutrient source, thus adding to the sustainability of biomass-based fuels.

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This thesis investigates an application of immobilized lipase for pre-treating wastewater containing fats and oils, which is difficult to treat practically. The kinetics of soluble lipase was studied for establishing background of the lipase. The immobilization of lipase was adopted in order to repeatedly use the expensive lipase. The developed immobilization methods were based on the characteristics of carriers, but covalent bonding of lipase was preferred because of strong adsorption nature. Three types of materials, nylon membrane and polystyrene-divinylbenzene and silica gel beads, were used for studying the lipase immobilization characteristics. The lipase from Canada rugosa was chosen because of its relatively high catalytic activity and commercial availability. The oily wastewater sources used were a simulated mixture of olive oil and distilled water as well as actual restaurant oily wastewater. A packed bed reactor packed with immobilized lipase was suitable for the study. Moreover, a comparative study of anaerobic digestion of lipase treated and un-treated oily wastewater was undertaken to evaluate the efficiency of the lipase pre-treatment method due to lack of the relevant literature in the enzymatic wastewater treatment field. The kinetics of lipase catalyzed hydrolysis reactions was investigated in a stirred tank reactor. The experimental results confirmed that the lipase catalyzed reaction obeyed Michaelis-Menten model. The optimal pH and temperature of the lipase catalysed hydrolysis reaction were 7 and 37°C, respectively. The conversion of oil to fatty acid was dependent on the reaction time and mass of the enzyme used. The lipase activities depended on the concentrations of some selected additives. Calcium ion improved lipase activity significantly amongst the additives used. / The immobilization of lipase was carried out using different materials, nylon membranes, polystyrene-divinylbenzene beads, and silica gel. Covalent adsorption was simple and successful for immobilizing the lipase onto nylon membrane which was pre-treated with HC1 solution for releasing amino groups. The adsorption of lipase was completed after only a 2-hour reaction time. It was much more practical for this shorter adsorption time (2 hours) rather than the 24 hours required for physical capillary adsorption of lipase. The properties of the immobilized lipase and the performance of the reactors we compared amongst the soluble and immobilized lipase forms. The immobilization, particularly for covalent bonding, made lipase more resistant to thermal deactivation. It was evident that the optimum temperature was shifted from 37°C for the soluble lipase to 45 and 40°C for immobilized lipase adsorbed onto nylon and polystyrene-divinylbenzene beads, respectively. The immobilized lipase could be used repeatedly with only little activity loss. The repeatedly operational stability made the reuse of the immobilized lipase possible. Comparison was also made between two types of beads, polystyrene-divinylbenzene beads and silica gels. Though polystyrene-divinylbenzene beads showed higher lipase activity and shorter adsorption time when compared to silica gels, the forme beads were not suggested for large scale study because of high cost of the beads. On improvement achieved in this work was that the 24 hours required for silanization of silica gel was reduced to only a few hours using evaporating 3-APTES in acetone instead of refluxing 3-APTES in toluene. / It is worthwhile to point out that much higher enzyme activity was obtained using the packed bed reactor as against the membrane reactor when aqueous oil emulsion was fed into the reactors. The lipase activity was 64.2% of soluble lipase activity for the immobilized lipase in the packed reactor but its activity was hardly detectable in the membrane reactor. Moreover, the operation of the packed bed reactor solved the of separating problem that severely hampered the lipase catalytic activity in the membrane reactor in aqueous phase. This result suggests that the packed bed reacts with the immobilized lipase is applicable in treating oily wastewater. The intrinsic parameters, Vmax and Km, were evaluated to study the internal diffusional effects of the porous spherical silica gel on the immobilized lipase. The changes of Vmax and Km for the immobilized lipase from those of the soluble lipase indicated that some alteration in the lipase intrinsic properties was caused by the immobilization of lipase. However, the magnitude of Thiele modulus suggested the immobilized lipase was most likely reaction controlling. In addition, good agreement for Vmax and Km from experiments and numerical model estimations seemed to suggest that the numerical model could be used for estimating Vmax and Km for the immobilized lipase. / An application was tried for conducting the hydrolysis of oily restaurant wastewater by soluble and the immobilized lipase. Enzyme activity of both forms was severely inhibited by the oily wastewater. The enzymatic activity was only 20% and 15% for soluble and the immobilized lipase, respectively, when compared to the initial activity value for the hydrolysis of olive oil by soluble lipase. Evaluation of the efficiency for the proposed lipase pre-treatment method was carried out by monitoring the performance of two anaerobic digesters. These two digesters were fed with lipase treated and untreated restaurant wastewater that was neutralised with KOH solution prior to feeding. The oil-floating problem was minimised by this saponification of fatty acids with potassium hydroxide. However, there was no clear sign of an improvement for the treatment efficiency of the anaerobic digesters in terms of COD removal and methane production rate resulted in digesting lipase treated oily wastewater when compared to the one without lipase pre-treatment.

Increasing demands for improved water quality in receiving waters, effluent reclamation and reuse have prompted wide interest in the use of wetlands for the treatment of wastewater. Over a four year period, domestic sewage effluent was treated using a range of gravel based, subsurface flow constructed wetland systems. Weekly samples at inlet and outlet points were assayed for suspended solids, biological oxygen demand, organic carbon, total kjeldahl nitrogen, ammonium, nitrate/nitrite, phosphorus, dissolved oxygen, temperature, pH and faecal coliform levels. The wetland system received secondary treated effluent for three years and primary settled effluent for one year. The potential of constructed wetland systems for nitrogen removal and potential pathogen reduction was investigated. Nitrogen removal was characterised by estimation of potential nitrification and denitrification rates within the system. Disinfection performance of the wetland system was assessed by enumeration of faecal indicator bacteria in the system influent and effluent, as well as with distance along the length of the system. The removal rate was estimated, considering influent and effluent faecal coliform concentrations as well as system hydraulic retention time and temperature. / Master of Science (Hons)

The principal aims of this thesis were to examine whether there were hydraulic links between individual on-site wastewater systems in sandy soils at Salt Ash and the Tilgerry Creek estuary near Port Stephens, New South Wales, and whether the chemical and microbiological contaminants from on-site systems could reach surface and groundwaters, and possibly lead to impacts on estuarine oyster growing waters. The research outcomes are contained within the thesis and in four refereed papers presented at conferences, and which have been subsequently published, or are in press. Copies of each of these papers are contained within the thesis Appendices. The presence of faecal contamination from domestic systems in the estuary, and surface drains in particular, has been confirmed by work contained in this thesis. The potential level of risk to human health from the consumption of contaminated oysters is, however, regarded as very low, although an assessment of health risk using established microbial assessment models has not been undertaken / Doctor of Philosophy (PhD)

The concern of water resource scarcity has always been the critical and debating issue for environmental interest groups, business operators, and politicians. The increasing global weather changes and economic development demands continue to attract new technologies and applications in water resource management, equally on clean water resource supply and wastewater treatment. K.Jie Company is a new start up company and a subsidiary of KNH Company, a nonwoven material manufacturing and converting company based in Taiwan and China. As part of the technology development, KNH’s internal business unit adapted nonwoven material in MBR (membrane bioreactors) for wastewater treatment. KNH decides to spin off this water business unit because of business decision after successful results and recognition. K.Jie Company will provider the key MBR modules as well as the total service provider for large industrial wastewater and municipal sewage treatment in Taiwan and in China in the near future.

<p>The aim of this project was to look into ten small sewer systems in the municipality of Laholm, in Sweden, in order to work out common assessment grounds for them. The sizes of the systems for purification of wastewater were within the range of 25 to 2000 population equivalents. Our method was to study literature, the laws and regulations applicable and the files at the municipality. The conclusion is that every sewer system is different and every situation is unique. We concluded that based on laws and assessment grounds sewer systems equal in size and pollution load ought to have similar demands attached to them. Four of the sewer systems are in need of adjustments or renovations. One sewer system in particular, Hishult, needs large-scale adjustments and improvements to live up to the demands attached to it. This sewer system is where we think the focus from the municipality ought to be the strongest, based on the result from this review. It requires most effort, time and money, to get it running with least amount of environmental impact. We also suggested levels for degree of purification for all of the sewer systems. As a common ground we set the demands equal to the ones for private sewer systems. The demand for purification of phosphorus was adjusted to if the system was equipped with chemical precipitation or not. Subsurface filters are left without measures. The focus of demands on systems of that kind is set to new construction or full scale restoration.</p>

Isolation and purification of anthocyanins from black bean canning wastewater by column chromatography with macroporous resins were investigated in this study. Different adsorption materials and adsorption conditions were compared and the most effective material and adsorption conditions were selected to purify anthocyanins. Purified anthocyanins then were identified by high performance liquid chromatography electrospray tandem mass spectrometry. The most effective macroporous resin was selected by comparing the adsorption performance of five different types of macroporous resins (Diaion Hp20, Sepabeads Sp70, Sepabeads Sp207, Sepabeads Sp700, and Sepabeads Sp710). Equilibrium adsorption isotherms of five resins with wastewater were measured and analyzed using Langmuir and Freundlich isotherm models. Both Langmuir and Freundlich models could describe the adsorption process. The adsorption and desorption behaviors of anthocyanins were studied using a dynamic method on the five types of resins, and Sp700 presented the highest adsorption capacity as well as desorption capacity, indicating that Sp700 is a good candidate for purification of anthocyanins from black bean canning wastewater. The most effective adsorption conditions were tested using Sp700. Dynamic adsorption and desorption were performed in glass columns packed with Sepabead Sp700 to optimize the purification process. Temperature during adsorption and desorption (25°C and 35°C) did not significantly affect the adsorption and desorption ratio. Adsorption ratio was significantly reduced when the flow rate increased from 1.5 mL/min to 2.5 mL/min. However, desorption ratio was not affected by flow rate (from 1.5mL/min to 0.3mL/min). Ethanol concentration (from 30% to 60%) did not affect desorption ratio. Four kinds of anthocyanins were identified in black bean canning wastewater. The major anthocyanins were delphinidin 3-glucoside, petunidin 3-glucoside, and maldvidin 3-glucoside, with a small amount of petunidin 3, 5-diglucoside also in the final product.

Nickel contaminated wastewater from plating industries is a major environmental concern. Current treatment methods are often expensive and can also create additional problems. Biosorption is an alternative treatment method that uses inexpensive biomaterials to sequester metals from aqueous solutions. In this study, acid washed barley straw (AWBS) was used for adsorbing nickel ions (Ni2+) from simulated nickel plating wastewater. The adsorption process was rapid and the equilibrium was reached in about an hour. An increase in the initial nickel concentration increased the equilibrium nickel uptake, and the maximum uptake was found to be 8.45 mg/g of AWBS when the initial nickel concentration was1000 mg/L at pH 5. Nickel adsorption was favorable at room temperature than 5oC and 40oC, better adsorption rate and equilibrium uptake was observed at 23oC. Increasing the pH from 3 to 7 increased the equilibrium nickel uptake and the maximum uptake was observed at pH 7, whilst the initial nickel ion concentration was 100 mg/L. The Freundlich isotherm model exhibited better fit with the equilibrium data than the Langmuir equation. Nickel was desorbed using hydrochloric acid solution at pH 2 and the desorption efficiency was 86%. FT-IR studies indicated the participation of hydroxyl, carboxyl and amide groups from cellulose, hemi-cellulose, protein and lignin of barley straw.