Ozonation is currently considered as one of the most effective microbial disinfection technologies due to its powerful disinfection capacity and reduction in levels of chlorinated disinfection by-products (DBP). However, ozonation of waters containing bromide can produce bromate ion above regulated levels, leading to tradeoffs between microbial and chemical risks. In efforts to meet increasingly stringent drinking water regulations and to be cost-effective, water suppliers are required to optimize ozone dosage. Therefore, there is a need to develop a robust and flexible tool to accurately describe ozone disinfection processes and contribute to their design and operation. Computational fluid dynamics (CFD) has come into use recently for evaluating disinfection systems. However, the focus of its application has been largely on modelling the hydraulic behaviour of contactors, which is only one component of system design. The significance of this dissertation is that a fully comprehensive three dimensional (3D) multiphase CFD model has been developed to address all the major components of ozone disinfection processes: contactor hydraulics, ozone mass transfer, ozone decay, and microbial inactivation. The model was validated using full-scale experimental data, including tracer test results and ozone profiles from full-scale ozone contactors in two Canadian drinking water treatment plants (WTPs): the DesBaillets WTP in Montréal, Quebec and the Mannheim WTP in Kitchener, Ontario. Good agreement was observed between the numerical simulation and experimental data. The CFD model was applied to investigate ozone contactor performance at the DesBaillets WTP. The CFD-predicted flow fields showed that recirculation zones and short circuiting existed in the DesBaillets contactors. The simulation results suggested that additional baffles could be installed to increase the residence time and improve disinfection efficiency. The CFD model was also used to simulate ozone contactor performance at the Mannheim Water Treatment Plant before and after installing new liquid oxygen (LOX) ozone generators and removing some diffusers from the system. The modelling results indicated that such changes led to an increase in effective residence time, and therefore an adjustment to operational parameters was required after system modification. Another significant contribution is that, for the first time, the Eulerian and Lagrangian (or particle tracking) approaches, two commonly utilized methods for predicting microbial inactivation efficiency have been compared for the study of ozone disinfection processes. The modelling results of two hypothetical ozone reactors and a full scale contactor suggested that the effective CT values predicted by the Lagriangian approach were slightly lower than those obtained from the Eulerian approach but their differences were within 10%. Therefore, both approaches can be used to predict ozone disinfection efficiency. For the full scale contactor investigated, the tracer residence time distribution predicted by the Euerlian approach provided a better fit to the experimental results, which indicated that the Eulerian approach might be more suitable for the simulation of chemical tracer performance. The results of this part of work provided important insight in understanding the complex performance of multiphase ozonation systems and played an important role in further improving CFD modelling approaches for full-scale ozone disinfection systems. The third significant contribution of this work is that a CFD model was applied to illustrate the importance of ozone residual monitoring locations and suggest an improved strategy for ozone residual monitoring. For the DesBaillets ozone contactors, the CFD modelling results showed that ozone residuals in the cross section of the outlets of some contactor chambers differed by an order of magnitude. The “optimal” area of monitoring locations however varied at different operational conditions. Therefore, it was suggested that multiple ozone residual sampling points should be installed based on CFD analysis and experimental studies, to provide more accurate indicators to system operators. The CFD model was also used to study the factors affecting the residence time distribution (RTD). The results suggested that the selection of the tracer injection locations as well as tracer sampling locations might affect the RTD prediction or measurement. The CFD-predicted T10 values at different outlet locations varied by more than 10% variation. It is therefore recommended that CFD modelling be used to determine tracer test strategy before conducting a full-scale tracer test, and multiple sampling points should be employed during tracer tests, if possible. In addition, a research based on full-scale investigation has also been done to compare the three different CT prediction approaches: CT10, integrated disinfection design framework (IDDF), and CFD, to determine the most appropriate method for design and operation of ozone systems. The CFD approach yielded more accurate predictions of inactivation efficacy than the other two approaches. The current results also suggested that the differences in the three approaches in CT predictions became smaller at higher contactor T10/T ratios conditions as the contactors performed more closely to ideal plug flow reactors. This study has demonstrated that the computational fluid dynamics (CFD) approach is an efficient tool for improving ozone disinfection performance of existing water treatment plants and designing new ozonation systems. The model developed in this study can be used for ozone contactor design, evaluation, and troubleshooting. It can also be used as a virtual experimental tool to optimize ozone contactor behaviour under varying water quality and operational conditions.

In the process of traditional water treatment, the humic acid and fulvic acid can be oxidized by chlorination; besides, it also produces small molecular organic compounds at the same time. Coagulation, flocculation, and sedimentation can reduce the concentration of the Assimilable Organic Carbon (AOC) significantly. An example of Ping-Ding water treatment plant was performed with sampling twelve times monthly from December 2008 to November 2009, the strong influence of chlorine, and coagulation, flocculation on the AOC can be observed. Comparing to the removal efficiency of water process in Ping-Ding water treatment plant, the AOC presented much stably in the distribution systems. We observed the data on the mean concentration of monthly sampling related to the operation unit in the water treatment plant. The Total Organic Carbon (TOC), and the Dissolved Organic Carbon (DOC) had the same trend with AOC in the water treatment process; it showed that TOC, and DOC had well relation to AOC in Ping-Ding water treatment plant. However, scrutinizing single monthly sampling, we found that the concentration of AOC did not fix out with the concentration of TOC and DOC at the same time. Therefore, results indicate that the AOC is mainly related to the smaller organic molecules of the TOC. In the series of sampling, we divided the influence of climate factor into the dry season and the pour season. The research discussed the five analysis items in the final results and discussion¡GTOC, DOC, UV254, UV254/DOC, and AOC. Basically, the concentration of the five analysis items on the pour season is higher than the dry season; it indicates that the raw water¡¦s concentration of organic carbon in Ping-Ding water treatment plant is higher during raining days. This can express the high concentration of the UV254, UV254/DOC, and AOC in water treatment plant in our work.

Die Kryptosporidiose des Kalbes stellt eine orale Infektion mit dem obligat pathogenen Erreger Cryptosporidium parvum dar. Sie verursacht hauptsächlich bei Jungtieren unterschiedlich schwere und zuweilen tödlich verlaufende Diarrhoe. Zur Analyse einer integrierten Bekämpfungsmaßnahme unter den Bedingungen einer natürlichen Infektionsexposition wurden 123 Kälber eines landwirtschaftlichen Nutzbetriebes in Thüringen untersucht. Die Tiere wurden in zwei Gruppen randomisiert nach ihrem Geburtstermin aufgeteilt. Der Gruppe H+ waren 62 Tiere zugehörig welche in den ersten sieben Lebenstagen Halofuginon in einer Dosis von 120 µg/kg KGW oral verabreicht bekamen und in Neopredisan® desinfizierten Buchten aufgestallt wurden. Gruppe H- stellte mit 61 Kälbern die unbehandelte Kontrolle dar, deren Buchten ausschließlich mittels Hochdruckreinigung gesäubert wurden. Alle Tiere wurden in den ersten vier Lebenswochen gewogen beginnend am ersten Lebenstag. In der 25. Lebenswoche fand eine zusätzliche Gewichtsbestimmung statt wobei die Tiere der H+ Gruppe im Mittel um 5,8 kg (p>0,05) schwerer waren als H- Tiere. Die Kälber beider Gruppen wurden in den ersten vier Lebenswochen jeden dritten Lebenstag hinsichtlich der Oozystenausscheidung, des Ernährungszustandes, des Trinkverhaltens, des Dehydratationsgrades und der Körpertemperatur untersucht. Zusätzlich wurde die Lunge auskultiert und die Konsistenz der Kotproben beurteilt. Durch die Halofuginonbehandlung und der zusätzlichen Desinfektion fand in der H+ Gruppe eine signifikante Senkung der Oozystenausscheidung bis zum 10. Lebenstag statt, jedoch waren die Tiere nach Absetzen der Behandlung für eine Infektion voll empfänglich. Das Auftreten von Diarrhoe zeigte eine positive Korrelation zur Oozystenanzahl untersuchter Kotproben. Die Anzahl an Tagen mit Durchfall korrelierte positiv und signifikant mit der Oozystenausscheidung. Für den Ernährungszustand, das Trinkverhalten, der Körpertemperatur sowie weitere klinischer Parameter bestand zu keiner Zeit eine signifikante Beziehung zur Kryptosporidiose. Damit erwies sich die integrierte Bekämpfung aus Halofuginonbehandlung und gezielter Desinfektion im für die Kälber kritischen Zeitraum der ersten zwei Lebenswochen als überaus effektiv. Allerdings muß bei derart geschützten Kälbern anschließend aufgrund einer offensichtlich nicht ausreichenden Immunisierung mit einer höheren Empfänglichkeit für C. parvum gerechnet werden.

Thesis--University of Oklahoma. / Includes bibliographical references (leaves 25-26).

Thesis (Ph. D.)--Drexel University, 2004. / Includes abstract and vita. Includes bibliographical references (leaves 210-223).

No description available.

Microbiological monitoring of water is of primary importance for preservation of human health, particularly in an arid zone like the U.S. southwest. In this work, infrared spectroscopic methods were developed to identify and quantify microorganisms present in water and water-related environmental samples. Focus of the work was primarily on evaluating the impact of various sterilization methods on microorganism physiology as gauged by the non-invasive approach of infrared spectroscopy. This work demonstrates that FTIR techniques can be used to identify changes in the physiology of microorganisms and that for heat treatment, a correlation between spectral changes and the viability of microorganisms can be made.

Poultry transport coops are rarely washed and demonstrate to be a major point of broiler carcass contamination. Our laboratory hypothesized that foaming disinfectants and cleaners commonly used within processing plants may be used to clean and disinfect poultry transport coops. The objective of this study was to evaluate treatments consisting of a low-pressure water rinse (LPWR), a foaming additive alone, foaming cleaner or peroxyacetic acid with a foaming additive to reduce bacteria on broiler transport coops. A high-pressure water rinse (HPWR) applied prior to and following treatments was also evaluated. Homogenized feces was evenly applied to the floors of pre-cleaned transport coops and allowed to dry. The first study used fresh layer feces and evaluated the treatments ability to reduce aerobic bacteria from the manure. The second study added a HPWR step to determine whether this technique would reduce bacteria. In the third study, Salmonella Typhimurium was added to the homogenized fecal slurry to evaluate how effectively these methods reduce aerobic bacteria and Salmonella on coop surfaces. The field study utilized laboratory treatments proven to be most effective on freshly soiled broiler integrator coops. All foaming treatments were applied using a compressed air foam system (CAFS) using a 1 inch fire hose. Ten minutes post-treatment, all surfaces were rinsed with a LPWR for 30 seconds to remove residual disinfectant. Samples were collected from the transport coops prior to and following treatments utilizing a flame sterilized 5 x 5 cm stainless steel template and a gauze swab pre-applied with buffered peptone water. All samples were stomached, serially diluted, spread plated onto agar plates, incubated for 24 h at 37° C and enumerated. The foam cleaner and peroxyacetic acid with a foam additive significantly reduced (P < 0.05) aerobic bacteria up to 4.84 to 5.17 logs, respectively when compared to the LPWR. The addition of a HPWR following product application significantly reduced bacteria on integrator coops, in the field study, but didn’t improve efficacy of our treatments in laboratory trials. These data suggest that a CAFS may be used in combination with disinfectants and cleaners to reduce bacteria on poultry transport coops.

Pharmaceutically active compounds (PhACs) have been found in wastewater effluents and receiving waters around the world. As yet there are no jurisdictions that regulate their release, or their impact on receiving water ecosystem health. The issue is complex due to the number of PhACs that exist, the variability in their structure and function, the variability in removal during different wastewater treatment processes, the potential for formation of metabolites and transformation products, and a lack of information on the impacts due to their presence on receiving waters. Gemfibrozil is a lipid regulating drug that is commonly found in wastewater effluents and receiving waters. It has been shown to partially degrade during biological wastewater treatment processes and has also been shown to produce reaction products through reactions with free chlorine. This thesis investigated the removal and transformation of gemfibrozil through several different wastewater treatment processes, namely biological removal and chlorination. Reactions between gemfibrozil and free chlorine led to the identification of four reaction products. The structures of three of the four reaction products were elucidated. The kinetics of formation of these reaction products were then investigated at a range of pH values, and in two wastewater matrices. One reaction product, 4’-ClGem was shown to form under conditions relevant to wastewater treatment. The impacts of gemfibrozil and 4’-ClGem presence on the abundance of suspended and biofilm bacteria in a simulated receiving water experiment were evaluated. It was shown that changes in the water matrix had more of an impact on bacterial abundance than presence of gemfibrozil or 4’-ClGem. A bacterial dose-response experiment showed a negative response at 10 mg/L exposure to 4’-ClGem, which is orders of magnitude higher then what would be found in receiving waters. In order to prevent the formation of chlorinated reaction products, it is necessary to remove gemfibrozil prior to disinfection. Recirculating biofilters (RBS), a biological technology for onsite or small-scale wastewater treatment, were explored as a potential treatment process for gemfibrozil removal. Results indicate that RBFs show promise as a robust technology to remove greater than 50% of influent gemfibrozil.

No description available.