Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The aim of this study was to describe the potential impact of stratification, and therefore destratification, and inflow hydrodynamics on the raw water quality in drinking water reservoirs, from the perspective of NOM. Investigations of the changes in the concentration, character and removal of NOM by conventional treatment processes during inflow hydrodynamics and thermal stratification were performed using observational and manipulative experiments and empirical and process based modelling. Further conceptual models were developed in place NOM within the existing frameworks of reservoir management from the perspective of other water quality hazards. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1321572 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The aim of this study was to describe the potential impact of stratification, and therefore destratification, and inflow hydrodynamics on the raw water quality in drinking water reservoirs, from the perspective of NOM. Investigations of the changes in the concentration, character and removal of NOM by conventional treatment processes during inflow hydrodynamics and thermal stratification were performed using observational and manipulative experiments and empirical and process based modelling. Further conceptual models were developed in place NOM within the existing frameworks of reservoir management from the perspective of other water quality hazards. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1321572 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

"March 2004" / Bibliography: leaves 221-234. / xxiv, 249 leaves : ill. (some col.), maps, photos (col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This research is part of the SA Water and Cooperative Centre for Water Quality and Treatment project entitled Destratification for control of phyloplankton. The major objective of this project was to assess a novel method of destratification and control of cyanobacteria, in particular Anabaena circinalis Rabenh. ex Born. et Flah, with the use of raft-mounted mechanical surface mixers with draft-tubes. / Thesis (Ph.D.)--University of Adelaide, School of Civil and Environmental Engineering, 2004

Hyrum Reservoir , Utah, was studied for one year during an artificial destratification project. Previously Drury et al. (1975) had studied Hyrum Reservoir for one year of stratified and one year of destratified conditions. The redistribution of dissolved oxygen to the hypolimnion significantly changed conditions for chemical and biological activities in the lower depths of the reservoir. The Aphanizomenon bloom increased with each year of destratification. The reservoir was changed by destratification so as to be suitable habitat for trout on a year round basis. Aerobic condi tions prevented iron from being released from the sediment into the aqueous phase . In summary the water quality of Hyrum Reservoir was highly affected by algal blooms, the interaction of bottom sediments with overlying waters especially in conjunction with spring and fall overturn, and the impact of materials and water flow from the Little Bear River.

L’objectif de cette thèse est de présenter des critères simples pour l’évaluation des performances d’une ventilation transversale. On définit l’efficacité et le rendement, calculés à partir du flux de déficit de densité créé par l’incendie. Après une étude préliminaire permettant de caler les modèles numériques, l’influence de différents paramètres sur ces valeurs a été évaluée. Dans un premier temps, l’étude a porté sur une seule trappe et a montré que le courant d’air dans le tunnel est le paramètre le plus important. A l’inverse, la forme de la trappe pour une surface donnée n’a que très peu d’importance, sauf dans des cas limites (fente sur toute la largeur du tunnel). L’étude d’un canton à huit trappes confirme l’importance du contrôle du courant d’air. Lorsqu’on diminue le nombre de trappes en conservant la même surface totale d’aspiration, cette sensibilité tend à disparaître, mais l’efficacité diminue. Enfin, l’étude de l’influence de l’encombrement montre une légère amélioration de l’efficacité, due à l’obstruction d’une partie de la section par des camions, qui bloquent les fumées au droit des trappes. / The aim of this study is to present simple criteria to evaluate the performances of a transverse ventilation system. Efficiency and yield have been defined, based on the flux of density deficit createdby the fire. After a preliminary study of numerical models, the influence of different parameters on those criteria has been investigated. First, the study focused on the simplified case of a single damper. We showed that the air flow speed in the tunnel is the more important parameter. On the contrary, the shape of the damper has little influence on the efficency, except in unusual cases (slit on the whole width of the tunnel). Then, the study of a longer portion of the tunnel confirmed the prominence of the limitation of air flow speed. Comparison with a case with fewer dampers but the same total extraction section showed that this sensibility to air flow speed tends to disappear for larger dampers, but that the efficiency is lowered. Finally the study of the influence of heavy-goods-vehicules obstructing the tunnel reports better results, due to the fact that big objects tend to confine smokes.

Artificial destratification equipment was installed in Lake Samsonvale in October 1995 to reduce the biomass of potentially toxic cyanobacteria in the reservoir. This study was undertaken to investigate the effects of the destratifier on the limnological processes occurring in the lake and to determine if operation of the destratifier has been effective at reducing the summer populations of Cylindrospermopsis raciborskii and Microcystis aeruginosa. The study showed that artificial destratification of Lake Samsonvale has been successful at reducing the surface to bottom thermal gradient and increasing dissolved oxygen concentrations at depth. While the destratifier has not resulted in the lake becoming completely 'mixed' during summer, it has weakened resistance to mixing from meteorological events, which has led to a reduction in mean concentrations of total and dissolved phosphorus during summer. Although not conclusive, it is likely that the influence of the destratifier is restricted to a narrow radial distance around the bubbleplumes during periods of strong stability, so internal loading may continue to provide a substantial source of nutrients for cyanobacterial growth, particularly in regions of the lake less influenced by the destratifier. The results for cyanobacteria are less encouraging. Despite the reduction in concentrations of dissolved phosphorus, the destratifier has not been effective at reducing summer populations of C. raciborskii and M. aeruginosa. On the contrary, there is evidence to suggest that populations have actually increased which could have serious operational consequences for the lake by mixing the previously buoyant cyanobacteria to the level of the water off-take. The growth season for C. raciborskii has been extended by up to 3 months and population onset now occurs during spring. This increase in spring populations could be a result of significantly greater baseline populations during winter, or the earlier germination of akinetes as a result of increased sediment temperatures. The seasonal successional relationship between C. raciborskii and M. aeruginosa appears to have shifted from one of alternating dominance between the two species to one of co-existence under conditions of intermediate disturbance. It was concluded that although the continued operation of the destratifier may prove useful to minimise water treatment costs through reducing internal loading of dissolved constituents, it has not been successful in achieving its original objective of controlling cyanobacterial populations in the lake.

L'objectif de cette thèse est de présenter des critères simples pour l'évaluation des performances d'une ventilation transversale. On définit l'efficacité et le rendement, calculés à partir du flux de déficit de densité créé par l'incendie. Après une étude préliminaire permettant de caler les modèles numériques, l'influence de différents paramètres sur ces valeurs a été évaluée. Dans un premier temps, l'étude a porté sur une seule trappe et a montré que le courant d'air dans le tunnel est le paramètre le plus important. A l'inverse, la forme de la trappe pour une surface donnée n'a que très peu d'importance, sauf dans des cas limites (fente sur toute la largeur du tunnel). L'étude d'un canton à huit trappes confirme l'importance du contrôle du courant d'air. Lorsqu'on diminue le nombre de trappes en conservant la même surface totale d'aspiration, cette sensibilité tend à disparaître, mais l'efficacité diminue. Enfin, l'étude de l'influence de l'encombrement montre une légère amélioration de l'efficacité, due à l'obstruction d'une partie de la section par des camions, qui bloquent les fumées au droit des trappes.

This doctoral thesis is focused on design of new equipment for aeration of water surface with low depth of water column. Aeration is one of ecological preventive methods to prevent growth of cyanobacteria. Increase of dissolved oxygen content in water mass leads to support of the growth of organisms which are disadvantaged by impossibility of movement in water mass and thus also to support biodiversity. Given biodiversity has a positive effect on water quality because it avoids the outbreak of one species of aquatic organism, in particular of cyanobacteria. Designed aeration equipment uses membrane formed by hollow fibre to transport oxygen into the water. When aeration dissolution of oxygen occurs directly on the membrane surface which prevents air leak in the form of bubbles. This type of aeration has low operating costs and high efficiency of input of the oxygen into the water. Distribution in the aquatic environment is ensured by special boat. This boat is moving on the water surface and the technology is installed on the upper deck. The aeration is carried out by an aeration module situated in the water. The movement of the boat is partially ensured by autonomous control.

This thesis deals with the process of destratification at the Brno dam reservoir within the activities of a larger project "Clean Svratka", aimed to improvement of water quality in the catchment area upstream the Brno dam. At the Brno dam the project "Implementation of measures at the Brno Reservoir" has been in progress for the third year. Its aim is the proposal and implementation of measures to suppress the cyanobacteria mass development in the dam lake. One of the key measures is aeration and mixing of dam water through a 20 aeration tower. The theoretical part of this thesis focuses on seasonal conditions in the dam lake, the technology suitable for destratification and aeration and possibilities of their use. In the practical part of the thesis the seasonal destratification and the impact of meteorological conditions are monitored.

Typescript (Photocopy) / Bibliography: leaves 166-189 / 2 v. : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--Dept. of Botany, University of Adelaide, 1991