D. Tech. (Department of Civil Engineering and Building, Faculty of Engineering and Technology), Vaal University of Technology / Growing demand for water due to increasing populations, industrialisation and water consuming lifestyles puts stress on existing water supply systems. To cater for the rising demand, water distribution networks are expanded beyond their design capacities and this creates transient “low-pressure-open-channel flow” (LPOCF) conditions. Current water supply models use “demand driven approach” (DDA) methodology which is not able to simulate transient LPOCF conditions, that poses an impediment to management/analysis of pressure-deficient networks. With a case study of the water supply network of Kampala City, LPOCF conditions were studied in this research. A “pressure/head driven approach” (PDA/HDA) was used in order to determine what demand is enabled by particular nodal pressures. Conversion of free surface to pressurised flow was analysed and modelled, with a view to clearly understanding occurrence of this phenomenon. The research demonstrated that if adequate pressures and flows are to be maintained, effectiveness of the water distribution network should be given as much attention as water production capacity. The research also indicated that when network pressures are low, the head-driven approach to water distribution modelling gives more accurate results than the traditional demand-driven methodology. Coexistence of free-surface and pressurised flow in networks prone to LPOCF conditions was confirmed and modelled. Results obtained highlighted the advantages of developing fully dynamic and transient models in the solution of transient LPOCF conditions in water distribution networks. Models developed allow application of PDA/HDA and DDA methodologies in systems that may exhibit LPOCF conditions thus enabling identification, understanding and analysis of the status of all sections of the network. These culminated in the development of a DSS to guide operational decisions that can be made to optimise network performance.

A study conducted by the World Health Organization and United Nations Children's Fund, concluded that approximately 768 million people worldwide are not receiving sanitary drinking water suitable for consumption. While there are many water treatment methods, lime softening proves to be one of the more effective approaches as it removes a wide variety of harmful compounds including arsenic, lead, mercury, and cadmium under the correct conditions. The greatest issues with lime softening on a smaller scale include the complexity of the chemistry and need for monitoring. By designing the system for groundwater sources and with a smaller capacity, this thesis hoped to reduce the level of monitoring, chemical expertise, and cost needed for operation. While promising results occurred in the removal of arsenic and total hardness, this project was unable to obtain consistent results and final water samples with pH values between the recommended standard of 6.5 to 8. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

In Turkey with increasing energy demand by industrialization and urbanization, hydropower seemed to be the most environmental friendly and sustainable solution for the problem. However, hydropower has also environmental effects especially when hydropower projects are numerous on a single river, and they use almost entire water in the river. Environmental flow as a new term became popular in media with increased density of small hydropower projects in Turkey. It is the required flow in the part of diversion for Run-off River type of hydropower plant in order to protect health of the river / in other words, to balance components of the river, including physico-chemical quality standards, surface and groundwater, geomorphological dynamics, social, economic, cultural and landscape values. In this study, an analysis utilizing hydrological (desktop) environmental flow assessment methods is prepared for Turkey, focusing on the Pazarsuyu Basin as a case study, and the results are compared with the applications done by the Governmental Institutions. Moreover, insufficient applications with regard to environmental flow assessment are given and reasons for public concerns are pointed out due to small hydropower development in Turkey.

It is an important task that design engineers in practice predict the local scour around bridge piers as accurately as possible because excessive local scour around bridge piers unbalance and demolish the bridges. Many equations have been proposed previously by various researchers, based on their experimental findings, but no general method has been developed so far due to the complexity of the topic. In the present study two new bridge pier groups were employed to investigate the inclination effect of the most upstream and downstream piers on the local scours around all piers. Total of 72 experiments have been conducted with 3 inclination angles, one of which representing the vertical case, each experiment lasting 6 hours, under uniform flow and clear-water conditions for a range of water depths and flow velocities on the uniform bed material. It is clearly observed and measured that the amount of local scour reduces substantially by the effect of inclination in the group piers, especially the reduction in the scour around the most upstream pier is found notable. Based on the experimental data, regression analyses are made and an empirical scour depth equation is developed for each individual pier in the pier groups studied. Comparisons with the similar studies performed by other researchers have been made and the results discussed.

The need of water and the limited sources, force the researchers to find the most economical and feasible solution in the design of a water distribution network. In this study, reliability and optimization of a water distribution network are taken into account together in the design stage of the network. The relationship between reliability of a water distribution network and its cost is examined during the design of a water distribution network. A methodology for deciding the reliability level of the selected design is proposed by examining the reliability-cost relationship. The design alternatives for the case study area are obtained by the aid of a commercially available software WADISO employing partial enumeration optimization technique. The reliability value for each of the design alternative is calculated according to Misirdali (2003)&rsquo / s adaptation based on the methodology proposed by Bao and Mays (1990) by the aid of a hydraulic network solver program HapMam prepared by Nohut&ccedil / u (2002). For purposes of illustration, the skeletonized form of Ankara Water Distribution Network subpressure zone (N8-1) is taken as the case study area. The methodology in this study, covering the relation between the reliability and the cost of a water distribution network and the proposed reliability level can be used in the design of new systems.

For a bridge engineer, it is very important to estimate the maximum scour depth around the piers as accurately as possible, in order to design the footing safely. Many experimental studies have been performed by several investigators until now, in order to obtain information about scouring mechanism. The aim of this experimental study is to examine the effect of inclination of the dual bridge piers on scour depth. The experiments have been conducted with dual pier models under clear-water conditions, for various uniform flow depths. Scour depths had been measured at four different points around the piers / namely upstream and downstream faces of both piers. Dimensional and non-dimensional scour curves have been developed and presented to show the temporal variation of scour depth. The depths of local scour around inclined piers have been observed to be smaller than the scour depths around vertical piers.

Water distribution networks are being designed by traditional methods based on rules-of-thumb and personal experience of the designer. However, since there is no unique solution to any network design, namely there are various combinations of pipes, pumps, tanks all of which satisfy the same pressure and velocity restrictions, it is most probable that the design performed by traditional techniques is not the optimum one. This study deals how an optimization technique can be a useful tool for a designer during the design to find a solution. The method used within the study is the partial enumeration technique developed by Gessler. The technique is applied by a commercially available software, i.e. WADISO SA. The study is focused on discrepancies between a network designed by traditional techniques and the same network designed by partial enumeration method. Attention is given to steps of enumeration, which are basically grouping of pipes, candidate pipe size and price function assignments, to demonstrate that the designers can control all the phases of optimization process. In this respect, special attention is given to price functions to show the effect of them on the result. The study also revealed that the cost of fitting materials cannot be included in the price function although it may have significant effect in a system composed of closely located junctions. The results obtained from this study are useful to show that although optimization methods do not provide a definite solution / partial enumeration method can assist designers to select the optimum system combination.

Errata sheet pasted onto front end-paper. / Bibliography: leaves 357-377. / xxvi, 514 leaves : ill. (some col.), fold. maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Civil and Environmental Engineering, 1999?

No description available.

Submitted in fulfillment of the requirements of the degree of Master of Applied Science in Biotechnology, Durban University of Technology, 2015. / In light of the world’s declining fossil fuel reserves, the use of microalgal biodiesel has come to the forefront as a potentially viable alternative liquid fuel. The depleting freshwater reserves make the feasibility of this concept questionable. The use of wastewater reduces the requirement for depleting freshwater supplies. This project aimed to determine the viability of municipal domestic wastewater effluent as a substrate for microalgal growth, in order to generate an economical and environmentally friendly source of biofuel. Wastewater effluents from three domestic wastewater treatment plants were characterized in terms of known microalgal nutrients viz., ammonia, phosphate and nitrates. Phosphate concentrations varied throughout the year and were found to be low (< 3 mgL-1) whilst ammonia and nitrate concentrations ranged from 0 to 10 mgL-1 throughout the experimental period. These wastewaters were found to be suitable for cultivating microalgae. The study explored the cultivation of Chlorella sorokiniana on pre- and post-chlorinated domestic wastewater effluent to assess their potential as a medium for high microalgal culture density and lipid production. Post-chlorinated wastewater effluent was found to be superior to pre-chlorinated wastewater effluent, as evident by the higher biomass concentration. This wastewater stream did not contain high concentrations of bacteria when compared to pre-chlorinated wastewater effluent. Nitrogen is an essential nutrient required for regulating the growth and lipid accumulation in microalgae. Cultures growing in post-chlorinated effluent had a lifespan of 18 d. Residual nitrogen in wastewater effluent supported microalgal growth for limited periods. Supplementation using cheap, readily available nitrogen sources was required for optimal biomass and lipid production. Urea, potassium nitrate, sodium nitrate and ammonium nitrate were evaluated in terms of biomass and lipid production of C. sorokiniana. Urea showed the highest biomass yield of 0.216 gL-1 and was selected for further experimentation. Urea concentrations (0–10 gL-1) were assessed for their effect on growth and microalgal physiology using pulse amplitude modulated fluorometry. A concentration of 1.5 gL-1 urea produced 0.218 gL-1 biomass and 61.52 % lipid by relative fluorescence. Physiological stress was evident by the decrease in relative Electron Transport Rate from 10.45 to 6.77 and quantum efficiency of photosystem II charge separation from 0.665 to 0.131. Gas chromatography analysis revealed that C16:0, C18:0, C18:1, C18:2 and C18:3 were the major fatty acids produced by C. sorokiniana. Wastewater effluent has been considered an important resource for economical and sustainable microalgal biomass/lipid production. The study showed that C. sorokiniana was sufficiently robust to be cultivated on wastewater effluent supplemented with urea. The results indicate that supplemented wastewater effluent was an acceptable alternative to conventional media. Using a relatively cheap nitrogen source like urea can certainly improve the techno-economics of large scale biodiesel production.