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.

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

An exploratory analysis of the trihalomethane (THM) and haloacetic acid (HAA) formation potential (FP) of Cedar Lake in order to produce formation potential curves for both THM and HAA; determine the THMFP and rate constant and compare to previous studies on Cedar Lake; and develop modeling for the formation potential loss of HAA from laboratory analysis of the raw lake water. While extensive modeling approaches have been explored for THM formation on different water sources, not many have been applied to the reservoir that supplies water to the Carbondale Water Treatment Plant and even fewer have explored the formation and modeling of HAA. Data for this study was obtained through laboratory experiment by applying bleach as a substitute for free chlorine to raw water samples obtained from Cedar Lake and quenching the samples at specific time steps to stop the reaction. Samples were then analyzed for THM content using standard method EPA 524.2R4.1 and HAA content using standard method EPA 552.2. The observed peak formation was 641.2701 µg/L for THM and 426.8 µg/L for HAA, but modeling fitted to the laboratory results indicated that a lower FP provided a better fitting of the data. A detailed analysis of the formed THM and HAA compounds indicated that a model produced for each compound resulted in more appropriate fitting by being able to account for the differing reaction rates and limiting factors of each reaction.

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

This research examined the impacts of water quality, phosphate-based corrosion inhibitors and pipe wall exposure on free chlorine (HOCl)/chloramine (NH2Cl) degradation and haloacetic acid (HAA)/N-nitrosodimethylamine (NDMA) formation in simulated distribution system water mains and household plumbing at bench-scale and pilot scale. In bench-scale bottle tests, the reactivity of fresh/pre-corroded pipe materials with HOCl/NH2Cl in decreasing order was: ductile iron, copper, lead. The addition of phosphate-based corrosion inhibitors generally increased HOCl/NH2Cl degradation for fresh iron coupons, but decreased HOCl/NH2Cl decay only for fresh copper coupons. Generally, these corrosion inhibitors did not impact HAA formation. Copper corrosion products, including Cu(II), Cu2O, CuO and Cu2(OH)2CO3, catalyzed HAA and NDMA formation. For HAAs, copper catalysis increased with increasing pH from 6.6 to 8.6 and/or increasing concentrations of these copper corrosion products. Interactions of copper with natural organic matter (NOM), likely by complexation, and the subsequent increase in the reactivity of NOM were proposed to be the primary reason for the increased HAA formation.NDMA formation increased with increasing Cu(II) concentrations, DMA concentrations, alkalinity and hardness but was inhibited by the presence of NOM. The transformation of NH2Cl to dichloramine (NHCl2) and complexation of copper with DMA were proposed to be involved in elevating the formation of NDMA at pH 7.0. Finally, in pilot-scale modified pipe loop tests, copper catalysis of NDMA formation was confirmed, especially under laminar flow conditions, and iron was shown to possibly catalyze NDMA formation under turbulent conditions. Orthophosphate increased the catalytic effects of iron but decreased copper catalysis on NDMA formation by either modifying the properties of the iron-associated suspended particles or reducing the dissolved metal concentrations. Orthophosphate increased chloramine decay when in contact with iron, likely by promoting nitrite formation, but orthophosphate decreased chloramine decay for copper and lead by reducing the availability of metal corrosion products.

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 research examined the impacts of water quality, phosphate-based corrosion inhibitors and pipe wall exposure on free chlorine (HOCl)/chloramine (NH2Cl) degradation and haloacetic acid (HAA)/N-nitrosodimethylamine (NDMA) formation in simulated distribution system water mains and household plumbing at bench-scale and pilot scale. In bench-scale bottle tests, the reactivity of fresh/pre-corroded pipe materials with HOCl/NH2Cl in decreasing order was: ductile iron, copper, lead. The addition of phosphate-based corrosion inhibitors generally increased HOCl/NH2Cl degradation for fresh iron coupons, but decreased HOCl/NH2Cl decay only for fresh copper coupons. Generally, these corrosion inhibitors did not impact HAA formation. Copper corrosion products, including Cu(II), Cu2O, CuO and Cu2(OH)2CO3, catalyzed HAA and NDMA formation. For HAAs, copper catalysis increased with increasing pH from 6.6 to 8.6 and/or increasing concentrations of these copper corrosion products. Interactions of copper with natural organic matter (NOM), likely by complexation, and the subsequent increase in the reactivity of NOM were proposed to be the primary reason for the increased HAA formation.NDMA formation increased with increasing Cu(II) concentrations, DMA concentrations, alkalinity and hardness but was inhibited by the presence of NOM. The transformation of NH2Cl to dichloramine (NHCl2) and complexation of copper with DMA were proposed to be involved in elevating the formation of NDMA at pH 7.0. Finally, in pilot-scale modified pipe loop tests, copper catalysis of NDMA formation was confirmed, especially under laminar flow conditions, and iron was shown to possibly catalyze NDMA formation under turbulent conditions. Orthophosphate increased the catalytic effects of iron but decreased copper catalysis on NDMA formation by either modifying the properties of the iron-associated suspended particles or reducing the dissolved metal concentrations. Orthophosphate increased chloramine decay when in contact with iron, likely by promoting nitrite formation, but orthophosphate decreased chloramine decay for copper and lead by reducing the availability of metal corrosion products.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Disinfection is an essential step in water treatment. This step, in most cases, is made by the use of chlorine and its derivatives, which have been quite effective. However, the use of chlorination to disinfect water produces various organic substances, among them, haloacetic acids (HAAs), a total of nine species: monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), monobromoacetic acid (MBAA), acid dibromoacetic (DBAA) tribromoacetic acid (TBAA) bromochloroacetic acid (BCAA), bromodichloroacetic acid (BDCA) and dibromochloroacetic acid (DBCA), which are haloreplaced carboxylic acids, which are toxic to humans, animals and plants. Recent studies have demonstrated an association between the development of some types of cancer with the haloacetic acids. Because of this, the Environmental Protection Agency (EPA) has established for the disinfection by-products a maximum contamination level (MCL) in treated water from 60 μg/L for the sum of five HAAS (MCAA, DCAA, TCAA, MBAA, DBAA ). The World Health Organization (WHO) also established MCL for DCAA (50 μg/L) and TCAA (100 μg/L). However, Brazil and the European Community do not set limits for these species. Therefore, this study aimed to develop an analytical method for the determination of Haas in water, using chromatographic techniques. Tests chromatographic separations were performed by ion chromatography (IC), high performance liquid chromatography (HPLC) and gas chromatography (GC) method development for the analysis of haloacetic acids in water. From the tests there were drawbacks in the analysis when it used IC or HPLC. By carrying out analysis by GC, that was with favorable conditions for the analysis, and a prerequisite for bypass was necessary. When the band worked with 0,5 to 50,0 μg/L were obtained correlation coefficients (r) ranging from 0,98 to 0,99, recoveries in the range 67 to 179%, detection limit of 0,08 to 7,2 μg/L and limit of quantification between 0,2 to 21,6 μg/L for the determination of Haas in water. / A desinfecção é uma etapa indispensável no tratamento de água. Esta etapa, na grande maioria das vezes, é feita pelo uso do cloro e seus derivados, os quais têm se mostrado bastante eficientes. Entretanto, o uso da cloração para desinfecção de água produz diferentes substâncias organocloradas, dentre elas, os ácidos haloacéticos (HAAs), em um total de nove espécies: ácido monocloroacético (MCAA), ácido dicloroacético (DCAA), ácido tricloroacético (TCAA), ácido monobromacético (MBAA), ácido dibromoacético (DBAA), ácido tribromoacético (TBAA), ácido bromocloroacético (BCAA), ácido bromodicloroacético (BDCAA) e ácido dibromocloroacético (DBCAA), que são ácidos carboxílicos halosubstituídos, os quais são tóxicos a seres humanos, animais e plantas. Estudos recentes têm demonstrado a associação entre o desenvolvimento de alguns tipos de câncer com os ácidos haloacéticos. Devido a isto, a Agência de Proteção Ambiental (EPA) tem estabelecido para esses subprodutos de desinfecção um nível de contaminação máximo (MCL) em água tratada de 60μg/L para a soma de cinco HAAs (MCAA, DCAA, TCAA, MBAA, DBAA). A Organização Mundial de Saúde (WHO) também estabeleceu MCL para DCAA (50μg/L) e TCAA (100μg/L). No entanto, o Brasil e a Comunidade Européia não estabelecem limites para estas espécies. Portanto, o presente trabalho teve como objetivo desenvolver um método analítico para a determinação de HAAs em água, utilizando técnicas cromatográficas. Testes de separações cromatográficas foram realizados por cromatografia iônica (IC), cromatografia líquida de alta eficiência (HPLC) e cromatografia a gás (GC) para desenvolvimento de método para a determinação dos ácidos haloacéticos em água. A partir dos testes verificaram-se inconvenientes nas análises quando se usou IC ou HPLC. Ao se proceder a análise por GC, esta se mostrou com condições favoráveis para a análise, sendo que uma etapa prévia de derivação foi necessária. Quando se trabalhou na faixa de concentração 0,5 a 50 μg/L, obtiveram-se coeficientes de correlação (r) variando de 0,98 0,99, recuperações no intervalo de 67 179%, limite de detecção entre 0,08 7,2 μg/L e limite de quantificação entre 0,2 21,6 μg/L para as determinações dos HAAs em água.

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.