Nutrients and cations have significant effect on activated sludge characteristics and therefore effect the efficiency of whole processes. To determine the properties in phosphorus deficient medium and the effect of calcium ions two reactor sets with two different phosphorus concentration (C/N/P=100/5/0.05 and C/N/P=100/5/1), three different concentrations of calcium (0.5, 5, 15 meq/L) were operated with 8 days of sludge residence time and an effective volume of 2 L. Results showed amount and composition of EPS was dependent on calcium and phosphorus concentrations. Except for the highest calcium concentration, increase in phosphorus concentration resulted in increase in total EPS production. Under phosphorus deficient conditions, calcium ions stimulated the production of carbohydrate type polymers and viscous bulking was observed. However, the increase in phosphorus concentration led to increase in protein type polymer production and bulking condition was cured. Addition of calcium ions increased conductivity in both cases, but increase in phosphorus concentration caused decrease in conductivity. Increase in phosphorus concentration had improved settleability, dewaterability and rheology of sludge. Moreover, effluent turbidity was decreased and COD removal efficiency was recorded as greater than 95 % for all calcium concentrations under phosphorus sufficient conditions. Microscopic analyses showed that under phosphorus deficient conditions flocs were weak, dispersed and nonresistant. Increase in phosphorus concentration resulted in improvement of floc structure. Same Enterobacter and Citrobacter species were identified at all calcium concentrations under phosphorus deficient conditions. Yet, under phosphorus sufficient conditions different species were identified in control reactor as compared to 5 meq/L and 15 meq/L concentrations.

ABSTRACT SULPHATE REMOVAL BY NANOFILTRATION FROM WATER Karabacak, Asli M.Sc., Department of Environmental Engineering Supervisor: Prof. Dr. &Uuml / lk&uuml / Yetis Co-advisor: Prof. Dr. Mehmet Kitis December 2010, 152 pages Excess sulphate in drinking water poses a problem due to adverse effects on human health and also due to aesthetic reasons. This study examines the nanofiltration (NF) of sulphate in surface water using a laboratory cross-flow device in total recycle mode. In the study, three NF membranes, namely DK-NF, DL-NF and NF-270, are used. The influence of the main operating conditions (transmembrane pressure, tangential velocity and membrane type) on the steady-state permeates fluxes and the retention of sulphate are evaluated. Kizilirmak River water is used as the raw water sample. During the experimental studies, the performance of NF is assessed in terms of the parameters of UVA254, sulphate, TOC and conductivity of the feed and permeates waters. Results indicated that NF could reduce sulphate levels in the surface water to a level below the guideline values, with a removal efficiency of around 98% with all three membranes. DK-NF and NF-270 membranes showed fouling when the surface water was fed directly to the system without any pre-treatment. MF was found to be an effective pretreatment option for the prevention of the membrane fouling, but no further removal of sulphate was achieved. Parametric study was also conducted. No change in flux values and in the removal of sulphate was observed when the crossflow velocity was lowered. The flux values were decreased as the transmembrane pressure was lowered / however there were not any decrease in the sulphate removal efficiency.

Alginates are copolymers of &beta / -D-mannuronic (M) and &alpha / -L-guluronic acids (G). In this study, Azotobacter vinelandii ATCC&reg / 9046 was used to produce alginate in a fermentor. The effect of parameters such as dissolved oxygen tension (DOT), agitation speed, initial concentrations of sucrose and calcium on the properties of alginate were examined. Changes of DOT in the range of 1 and 10 % affected alginate production. The optimum DOT giving high alginate yield (4.51 g/L) and maximum viscosity was observed as 5 % yielding moderate GG-blocks of 55 %. Both high and low agitation levels reduced alginate production, but these conditions increased GG-block alginates as 76 and 87 % at 200 and 700 rpm, respectively. Moderate sucrose and calcium concentrations, 20 g/L and 50 mg/L, respectively were found better since further increase in their concentrations did not lead to a considerable improvement in alginate production and quality. Sodium alginates produced in this work were investigated for maximum heavy metal uptake with a special focus on copper ion and the highest copper uptake was around 1.9 mM Cu2+/g alginate. Findings showed that the block distribution of alginate was not as important as expected for copper removal. Alginate together with calcium ions was used for the removal of turbidity. The amount of GG-block was found to be important in turbidity removal. Alginate having 55 % GG block and 8.9 cP viscosity resulted in a final turbidity lower than 1 NTU at 2 mg/L of alginate with 60 mg/L of calcium ion.

Endocrine disrupters and trace organic contaminants are recently recognized contaminants in wastewaters. Current concept is the multibarier approach where the contaminants are removed from the water cycle both by water and wastewater treatment facilities, as well as natural die-away. In this thesis work LC/MS/MS determination of selected EDC compounds, namely, diltiazem, progesterone, estrone, carbamazepine, benzyl butyl phthalate and acetaminophen, at ultra trace levels, have been carried out by optimizing analytical parameters. In addition, new methods were developed for their analysis in sludge samples at sub ppb levels. Following optimization and method development, occurrence of these contaminants in wastewaters and their removal in two full-scale and two pilot-scale membrane biological reactors (MBRs) was studied. Progesterone, estrone and acetaminophen were completely removed from wastewater by biodegradation. CBZ and diltiazem were not removed at all during the study. There was little effect of flux and sludge retention times on the removal of selected EDCs in these membrane plants. In SBR combined with membrane filtration, 13 different micropollutants, including Fluoxetine (FLX), Ibuprofen (IBP), Naproxen (NPX), Diclofenac (DCF), Carbamazepine (CBZ), Trimethoprim (TMP), Roxithromycin (ROX), Erythromycin (ERY), Sulfamethoxazole (SMX), Diazepam (DZP), Galaxolide (GLX), Tonalide (TON), Celestolide (CEL). CEL, GLX, TON and FLX were removed by adsorption onto the sludge while ROX, ERY, SMX, IBP and NPX were removed by biological degradation. The CBZ, DZP, TMP and DCF were not removed by biodegradation or adsorption. Whereas, following the addition of powdered activated carbon, all these compounds were removed entirely from the wastewater stream by accumulating in sludge.

<p>The fully integrated 3-D, time dependant, hydrodynamic and sediment transport numerical model ECOMSED was used to simulate flow and sediment transport in rivers. ECOMSED was originally developed for large water bodies such as lakes and oceans and solves the primitive equations of RANS along with a second order turbulence model in an orthogonal curvilinear σ- coordinate system. The availability of the model as an open FORTRAN source code made modifications and addition of new models possible. A new bed load transport model was implemented in the code as well as improvements in treatment of river roughness parameterization, bed form effects, and automatic update of flow depth due to bed evolution. The model was applied to 1- km long reach of the River Klarälven, Sweden, where it bifurcates into two west and east channels. The water surface and the flow division in the channels were made in agreement with field data by spatially varying the roughness. However, the spatial distribution of the bed shear stress was not realistic. Improvements were made in the bottom boundary condition to represent the variable effects of bed forms on roughness depending on the flow regime and the flow depth. The improved model realistically reproduced the flow field as well as the sediment transport processes in the river Klarälven.</p>

The aim of this thesis is to analyze the role that environmental technology plays in the solution of environmental problems in cities, and discuss models and conditions that can facilitate the processes of selection, implementation and use of environmental technologies in and by cities. The technological component is perhaps one of the most important characteristics of modern cities. The dependence of humans on technology is in most cases a given, something that is not ignored in the sustainability debate. The development and implementation of new, “better” technologies is however hindered by the inertia that modern societies have and the influence of the dominant systems (e.g. economic systems based on growth, extraction of natural resources and environmental disturbance). So-called environmental technologies are not always able to efficiently compete against other technologies that are embedded in societies by lock-in mechanisms, e.g. learning by doing and using, scale economies, subsidies, and network externalities. Even with the “right” technologies, an exclusively techno-centered approach to sustainability can result in other problems, and it might reduce the sustainability debate and the cities’ role in it to discussions of an administrative nature. The actual role of local actors and their agency must be also considered in the models and frameworks directed at understanding sustainability transition processes. It is thus important to analyze the dynamics of technology selection, implementation, use and diffusion in cities from a stakeholders’ perspective as well. Not only is the availability of technology of interest for understanding the impact it has on the environment, but also the intensity of its use. This has resulted in increased attention from politicians and scholars on the so-called global cities (e.g. London, New York, Tokyo), which are characterized by their intense use of e.g. transport, security and surveillance, and information and communication. Paradigmatic models of sustainability can however be contested when the role of local actors, power and agency are considered in detail and not isolated from the context. Some authors recognize the need to address what they call “ordinary cities”, since focusing on the cities’ comparative level of development (be it political, economic or technological) hinders the possibility of bidirectional learning. In the end, sustainability is a “collective good,” which means that it is in everyone’s interest to coordinate efforts and learn from the best practices, regardless of where they come from. This thesis focuses on “ordinary cities,” and promises to offer conclusions that can contribute to a better understanding of how societies can learn from each other and how environmental technologies can have deeper and better results when implemented in different contexts than the ones where they were developed. Two questions related to the process of environmental-technology adaptation are addressed in this thesis: How do technology adaptation processes for the solution of urban environmental problems take place in cities? And how do cities benefit from environmental technologies? It is found that environmental technology is not only seen as a solution to environmental problems in cities, but every day more as a component of strategies to attract attention and compete for resources in national and international markets. Cities have different adaptation and learning strategies. This means that technological solutions have to be flexible and adaptive to local conditions, and allow for vernacular knowledge and past experiences to enrich their performance by facilitating their connection to existing systems. Learning between cities is important and necessary for global sustainability transitions. When it comes to environmental technology, this process is facilitated by strong proof-of-concept projects. Such projects are not only expected to be able to show their technical ability to solve a problem, but must also offer contextual connections to the problems faced by interested cities or potential implementers.

Lightweight engineering plastics have been increasingly used in automotive applications(3), this tends toward more fuel efficient vehicles(1). Glass reinforced plastics commonly include thermosetting polymers. These cannot be re-moulded, unlike thermoplastics, thus thermoset scrap is currently disposed of in landfill. This is increasingly targeted by legislation(14) and is becoming more expensive. This thesis describes work to maximise resource recovery from scrap thermoset composites. A review of relevant literature identified thermal processes for treating scrap thermoset composites. Combustion is particularly suitable for the mixed and contaminated materials arising from end of life vehicles. The literature showed that heating glass fibres reduced their properties, which is a concern for any thermal recycling process. The methodology of this work is to recover energy from the composite polymer and reuse the incombustible residues. Two experimental processes are reported: Fluidised Bed Co-combustion of Thermoset Composites with Coal. The common composite filler of calcium carbonate captures the sulphur emissions from the coal combustion. Results show that scrap composites can successfully be burned in a commercial scale fluidised bed. Retention of the sulphur from the coal by the composite filler was up to 75 % of the input. Although a technical success, economic analysis shows this disposal to be unviable compared with similar desulphurisation via crushed limestone. Fluidised Bed Thermal Processing Rig for Recovering Glass Fibres. The incombustible constituents of a crushed Sheet Moulding Compound were released from processing above 400 ° C in the fluidised bed test rig. The reinforcing glass fibres were elutriated as monofilaments, suitable for use in a veil product, and recovered from the flue gases. Scanning Electron Microscopy showed that the fibres were intact. The tensile strength of fibres from 450°C processing was reduced by approximately 50% and by 90% from 650°C(73). Strength was also found to reduce with increasing time at a temperature(76) . Flue gas analysis showed that carbon monoxide and hydrocarbons were present. This indicated that full combustion did not take place and the associated heat energy lost. Measured nitrogen oxides and sulphur dioxide concentrations were low. After initial testing, the test rig was refined by the incorporation of a Rotating Screen Collector to separate the fillers and fibres. The fibre contamination was reduced by 50% via this novel equipment. Fibre recovery rates of up to 57% were achieved. Resin Decomposition Model. Results indicate that the resin endothermic energy of decomposition maintained the temperature of the Sheet Moulding Compound significantly below the bed temperature.

Cementitious building components, although widely used in low-income countries, are too expensive for many applications related to low-income housing. This thesis explores three options for reducing component cost: 1. Use of local fine aggregates, often with clay contamination, instead of low-fines sands transported from a distance. 2. Improved designs, to achieve better material economy. 3. Change of production environment, from on-site to component prefabrication followed by transport to site. Water storage tanks for rainwater harvesting were used as the example for component design, and as a case-study for considering the effect of changing the production environment. The work showed that: In some cases, use of local aggregates will give a cost saving of around 10%. Improved design can give significant reduction in materials usage, of up to 40%. Off-site prefabrication of components, followed by on-site assembly to produce the desired product, does not seem preferable to the prevelant practice of entirely on-site production from raw materials. However, factory-based manufacture of complete products, followed by transport to site, has a number of attractions over entirely on-site production. Out of the three options examined, improved component design offers the greatest benefits for the case study considered.

The rise velocity of injected air phase from the injection point toward the vadose zone is a critical factor in in-situ air sparging operations. It has been reported in the literature that air injected into saturated gravel rises as discrete air bubbles in bubbly flow of air phase. The objective of this study is to develop a quantitative technique to estimate the rise velocity of an air bubble in coarse porous media. The model is based on the macroscopic balance equation for forces acting on a bubble rising in a porous medium. The governing equation incorporates inertial force, added mass force, buoyant force, surface tension and drag force that results from the momentum transfer between the phases. The momentum transfer terms take into account the viscous as well as the kinetic energy losses at high velocities. Analytical solutions are obtained for steady, quasi-steady, and accelerated bubble rise velocities. Results show that air bubbles moving up through a porous medium equilibrate after a short travel time and very iv short distances of rise. It is determined that the terminal rise velocity of a single air bubble in an otherwise water saturated porous medium cannot exceed 18.5 cm/sec. The theoretical model results compared favorably with the experimental data reported in the literature. A dimensional analysis conducted to study the effect of individual forces indicates that the buoyant force is largely balanced by the drag force for bubbles with an equivalent radius of 0.2-0.5 cm. With increasing bubble radius, the dimensionless number representing the effect of the surface tension force decreases rapidly. Since the total inertial force is quite small, the accelerated bubble rise velocity can be approximated by the terminal velocity.

Current activated sludge models are deterministic in character and are constructed by basing on the fundamental biokinetics. However, calibrating these models are extremely time consuming and laborious. An easy-to-calibrate and user friendly computer model, one of the artificial intelligence techniques, Artificial Neural Networks (ANNs) were used in this study. These models can be used not only directly as a substitute for deterministic models but also can be plugged into the system as error predictors. Three systems were modeled by using ANN models. Initially, a hypothetical wastewater treatment plant constructed in Simulation of Single-Sludge Processes for Carbon Oxidation, Nitrification &amp / Denitrification (SSSP) program, which is an implementation of Activated Sludge Model No 1 (ASM1), was used as the source of input and output data. The other systems were actual treatment plants, Ankara Central Wastewater Treatment Plant, ACWTP and iskenderun Wastewater Treatment Plant (IskWTP). A sensitivity analysis was applied for the hypothetical plant for both of the model simulation results obtained by the SSSP program and the developed ANN model. Sensitivity tests carried out by comparing the responses of the two models indicated parallel sensitivities. In hypothetical WWTP modeling, the highest correlation coefficient obtained with ANN model versus SSSP was about 0.980. By using actual data from IskWTP the best fit obtained by the ANN model yielded R value of 0.795 can be considered very high with such a noisy data. Similarly, ACWTP the R value obtained was 0.688, where accuracy of fit is debatable.