Impact of Sludge Volume and Water Quality on DBPs in a Full-Scale Water Works The goal of this research was to determine the role of settled sludge on the formation of disinfection by-products in a full-scale water treatment plant. The occurrence of disinfection by-products in chlorinated drinking water has become a major concern to treatment facilities in their effort to comply with strict regulations set by the United States Environmental Protection Agency. Water samples were tested for trihalomethanes and haloacetic acids at both ends of the sedimentation process to evaluate formation over the length of the basin. Sludge volume and other important water quality parameters were also measured at the time of sample collection. Statistical analyses were used to analyze contributions from the sludge and to determine influential factors leading to disinfection by-product formation. The treatment plant incorporated chlorine dioxide into the treatment process seasonally, and effects were evaluated. Predictive models were developed from the data to be used under various treatment methods. The models created for trihalomethanes and haloacetic acids require measurements of chlorine dose, reaction time, total organic carbon, pH, water temperature, and sludge volume. The models performed well in predicting actual trihalomethane and haloacetic acid concentrations and could serve as a valuable tool in the control of disinfection by-products. DBP Formation Potential of Settled Sludge in a Full-Scale Water Treatment Facility It is still a common occurrence for water treatment facilities to store sludge in sedimentation basins for extended periods, rather than relying on mechanical collection equipment. The goal of this research was to characterize contributions from settled sludge to the formation of disinfection by-products (DBPs), and determine whether continuous removal is essential in the control of DBPs. Samples were taken from top and bottom sludge layers in the sedimentation basin and water was extracted either by draining or centrifugation. The water was analyzed for trihalomethanes and haloacetic acids and water quality measurements were recorded. Concentrations of both DBPs were very high in top-layer sludge; trihalomethanes ranged from 321.5 μg/L to 568 μg/L and haloacetic acids ranged from 74.6 μg/L to 409.8 μg/L. Evidence of biodegradation was observed in the bottom-layer sludge. The water samples were dosed with 4 mg/L chlorine, the United States Environmental Protection Agency's maximum residual disinfectant level, to determine if further DBP formation was possible. The extracted water from the bottom-layer sludge was shown to form high trihalomethane concentrations when chlorinated, and haloacetic acid concentrations were observed to increase when samples from the top-layer sludge were chlorinated. / Master of Science

In an effort to maintain compliance with current and future United States Environmental Protection Agency regulations governing haloacetic acids (HAAs) and trihalomethanes (THMs), the Blacksburg, Christiansburg, VPI (BCVPI) Water Authority in Radford, Virginia elected to eliminate prechlorination and replace it with preoxidation using chlorine dioxide (ClO2). Prior to full-scale application at the BCVPI Water Treatment Plant, jar testing was done to determine the effects of ClO2 on the formation of HAAs and THMs. Jar testing results showed a significant reduction in THM formation potential when 2.0 mg/L ClO2 was applied to raw water and chlorination was delayed. Chlorine dioxide doses less than 2.0 mg/L were statistically insignificant in the reduction of THM formation potentials below samples that were prechlorinated according to the BCVPI Water Treatment Plant's current practice. Likewise, ClO2 did not alter HAA formation potentials in such a way that statistical differences could be detected between ClO2 pretreatment and prechlorination, even at a dose of 2.0 mg/L ClO2. The two inorganic byproducts of ClO2, chlorite and chlorate, were also measured following jar tests. Chlorite concentrations increased with an increased ClO2 dose, but remained below 1.0 mg/L. Chlorate was formed in all jar-test samples. / Master of Science

Disinfectants, such as chlorine, are widely used in water treatment plants to ensure the safety and quality of drinking water. However, these disinfectants easily react with some natural or man-made organic compounds in raw water and then form disinfection by-products (DBPs). For example, halogenated acetic acid (HAAs) and trihalomethanes (THMs) are two main components of DBPs. The purposes of this study are to analyze the concentration of DBPs including HAAs and THMs in drinking water and investigate the distribution of DBPs in the processes of three advanced water treatment plants in southern Taiwan. The analytical method of HAAs is based on the USEPA Method 552.3 and THMs is analyzed by headspace solid-phase microextraction(HS-SPME). Moreover, some factors which may influence the formation of DBPs such as dissolved organic carbon (DOC) and water temperature are also analyzed to further discuss the relation to the generation of DBPs. Through this study, the results could be the reference for operation control in water treatment plants and regulation setting in Taiwan. The samples of drinking water were collected in three advanced water treatment plants in southern Taiwan from June 2007 to April 2008. The analyzed HAA9 results were 28.71 ¡Ó 14.77£g g / L in Plant A, 24.43 ¡Ó 15.70 £g g / L in Plant B, 28.91 ¡Ó 14.38 £g g / L in Plant C. Comparing the HAA5 results with the maximum contaminant level (MCL) in USEPA, it was clearly found that all the values were under the standard of 60 £g g / L. As to THMs, the results were 9.99 ¡Ó 3.39£g g / L in Plant A, 0.94 ¡Ó 2.12 £g g / L in Plant B, 28.91 ¡Ó 14.38 £g g / L in Plant C and greatly under the EPA standard of 80 £g g / L in Taiwan. Furthermore, the major species of HAA9 in order were BCAA and TCAA while THMs was trichloromethane (CHCl3). In the relation between DOC and DBPs, the results demonstrated that DOC was more relative to DBPs in raw water; meanwhile, the water temperature did not show great relation. In general, despite the poor correlation, it was still could conclude that the concentration of DBPs increases with the increase of DOC and temperature. In conclusion, the research results showed that the removal efficiency of DBPs in Plant A and B (UF/RO system) is greater than Plant C (Biological Activated Carbon system, BAC system ), and all three advanced water treatment plants could show greatly effectiveness in drinking water quality improvement. However, higher concentration of bromine products in HAAs was discovered in this research. It was suggested that the phenomenon should be further discussed and controlled.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23871号 / 工博第4958号 / 新制||工||1775(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 伊藤 禎彦, 教授 藤原 拓, 教授 越後 信哉 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Issues of Disinfection By-Product (DBP) formation in response to chlorination in drinking water treatment systems is a common issue encountered by WTP operators. Efforts to minimize DBP formation are complicated by the presence of zebra mussels, which may inhabit the raw water intake of WTPs. While chlorination at the intake to control zebra mussel populations is effective, the formation of DBPs is exacerbated. Methods for reducing DBPs are explored, including adjusting the location for chlorine additions in the treatment sequence. Multivariate models for Total Trihalomethane (TTHM) and Haloacetic Acid (HAA) subspecies are employed to show that in some instances pre-chlorination can be reduced to lower DBP formation, while post-chlorination can be increased. A Regression model (R2 of 0.75) predicts that DBP levels can be lowered by post-chlorination rather than pre-chlorinating raw water for portions of the year except during the combatable life stage to assist in zebra mussel control. A second multivariate regression model for TTHM (R2 = 0.91) which includes bromide, a variable which, due to lack of data, was previously unused, is described and demonstrates that DBP levels can be reduced by lowering pre-chlorination levels. Finally, a Bayesian network is developed using the Webweavr-IV Toolkit, utilizing causal relationships between raw water quality parameters in the form of conditional probabilities. The results show that the average cancer risk can be decreased by while still maintaining zebra mussel control and simultaneously decreasing the incremental cancer risk, which currently fluctuates between 1 in 50,000 to 100,000 in Ontario. / Canada Research Chair Program, Ontario Research Foundation

This project focuses on two important topics which may pose hazards to human health. Firstly, drinking water disinfection by-products (DBPs), which are generated by the chemical disinfection of water have been investigated. What has not been shown is the effect of DBPs in human germ cells as well as somatic cells and whether oxidative stress is involved in the mechanism of genotoxic action. Three different DBPs (halo acetic acids: HAAs), together with the antioxidants – catalase and butylated hydroxyanisole (BHA), were investigated in peripheral blood cells and sperm from healthy individuals using the Comet assay and lymphocytes only using the micronucleus assay. Secondly, nanoparticles of the non-steroidal anti-inflammatory drugs (NSAIDs), aspirin and ibuprofen, have been investigated in patients with respiratory diseases, in the micronucleus assay and the Comet repair assay. NSAIDs inhibit cyclooxygenase enzyme activity, which plays part in tumour progression. In the Comet assay, BHA and catalase were able to reduce DNA damage in both cell types compared to HAAs alone. Similarly, in the micronucleus assay, micronuclei were reduced with the antioxidants, suggesting oxygen radical involvement in both assays. With the NSAIDs, reductions were seen for DNA damage in the micronucleus assay with aspirin and ibuprofen nanoparticles compared to their bulk forms. Using the Comet repair assay, aspirin and ibuprofen nanoparticles aided repair of DNA to a greater extent than their bulk counterparts, which in turn showed better repair compared to samples repaired without NSAIDs. These observations show the importance of DBPs and NSAIDs in genotoxic public health issues.

This project focuses on two important topics which may pose hazards to human health. Firstly, drinking water disinfection by-products (DBPs), which are generated by the chemical disinfection of water have been investigated. What has not been shown is the effect of DBPs in human germ cells as well as somatic cells and whether oxidative stress is involved in the mechanism of genotoxic action. Three different DBPs (halo acetic acids: HAAs), together with the antioxidants – catalase and butylated hydroxyanisole (BHA), were investigated in peripheral blood cells and sperm from healthy individuals using the Comet assay and lymphocytes only using the micronucleus assay. Secondly, nanoparticles of the non-steroidal anti-inflammatory drugs (NSAIDs), aspirin and ibuprofen, have been investigated in patients with respiratory diseases, in the micronucleus assay and the Comet repair assay. NSAIDs inhibit cyclooxygenase enzyme activity, which plays part in tumour progression. In the Comet assay, BHA and catalase were able to reduce DNA damage in both cell types compared to HAAs alone. Similarly, in the micronucleus assay, micronuclei were reduced with the antioxidants, suggesting oxygen radical involvement in both assays. With the NSAIDs, reductions were seen for DNA damage in the micronucleus assay with aspirin and ibuprofen nanoparticles compared to their bulk forms. Using the Comet repair assay, aspirin and ibuprofen nanoparticles aided repair of DNA to a greater extent than their bulk counterparts, which in turn showed better repair compared to samples repaired without NSAIDs. These observations show the importance of DBPs and NSAIDs in genotoxic public health issues. / United Kingdom India Education and Research Initiative (UKIERI).

Ce travail a été consacré à l'étude des sous-produits de désinfection formés lors de la chloration des eaux de piscine publiques. En effet, parallèlement à son action désinfectante, le chlore réagit sur les composés organiques et minéraux introduits dans l'eau des bassins par les baigneurs (urine, sueur, ...) pour former des sous-produits indésirables (chloramines et composés organohalogénés).Des analyses d'urée, principal composé précurseur de chloramines inorganiques, ont été effectuées dans une cinquantaine d'eaux de piscine. Les concentrations mesurées ont été comprises entre 0,14 et 3,67 mg/L (valeur moyenne : 1,08 mg/L ; écart-type : 0,70 mg/L). L'étude de la réactivité du chlore sur l'urée (cinétique et consommation de chlore) effectuée sous différentes conditions expérimentales a mis en évidence une très grande stabilité de l'urée en présence de chlore libre dans les eaux de piscines.Les analyses de sous-produits de chloration ont démontré que l'hydrate de chloral représente l'un des sous-produits de chloration majoritaire avec les acides dichloroacétique et trichloroacétique. Cette étude a aussi permis de déterminer la constante cinétique d'hydrolyse de l'hydrate de chloral dans l'eau, l'influence du pH et de la température sur la vitesse d'hydrolyse, ainsi que les potentiels de formation d'hydrate de chloral à partir de quelques constituants de l'urine.La dernière partie de ce travail a porté sur l'étude de la réactivité de l'ozone sur le chlore et sur des sous-produits de chloration ainsi que sur l'étude de l'incidence d'une préozonation des eaux de piscines (en absence et en présence de chlore libre) sur la formation des sous-produits organohalogénés lors d'une post-chloration. / The aim of this work was to study of the formation of disinfection by-products during the chlorination of public swimming pools water. In parallel to its disinfecting action, chlorine reacts with organic and inorganic compounds introduced into the swimming pool water by bathers (urine, sweat, ...) to form undesirable by-products (chloramines and organohalogenated matters).A statistical study of the presence of urea, the major component of urine and sweat, and the main precursor compound of inorganic chloramines, in public swimming poolwater has been made. Measured concentrations were between 0.14 and 3.67 mg/L (mean value: 1.08 mg/L, s.d: 0.70 mg/L). The study of the reactivity of chlorine with urea (kinetic and chlorine consumption) made under different experimental conditions, showed a very high stability of urea in the presence of free chlorine in the pools water.Analysis of chlorination by-products showed that chloral hydrate, with the dichloro and the trichloroacetic acids, is one of the major chlorination by-products found. This study also determined the kinetic rate constant of hydrolysis of chloral hydrate in water, the influence of the pH and the temperature on the rate of hydrolysis and the potential of chloral hydrate formation from some constituents of the urine.The last part of this work was focused on the study of the reactivity of ozone on chlorine and some disinfection by-products, as well as the study of the impact of preozonation of swimming pools water (in absence and presence of free chlorine) on the formation of organohalogenated by-products during a post-chlorination.