Tesi sul tema "Water Purification Disinfection By-products"

Disinfection by-products (DBPs) are a major group of water contaminants and their role in causing adverse health outcomes, including adverse pregnancy outcomes, endocrine disruption, respiratory related adverse health outcomes and cancer has been subject to extensive epidemiological and toxicological research and review. Determination of safe exposure to DBPs, particularly within drinking water supplies, has been a topic of extensive debate, with a wide range of acceptable levels set across the industrialized world. The focus of the research in this thesis was on two of the main health outcomes associated with DBP exposure, namely adverse pregnancy outcomes and asthma related symptoms. To assess adverse pregnancy outcomes in Perth, an extensive classification quantification of the major DBPs in Perth drinking water was conducted. A registrybased prevalence study was carried out to assess birth defects in relation to high, medium and low DBP areas (defined by the water sampling and analysis). It was found that women living in high THM areas are 22% (odds ratio (OR) 1.22, 95% confidence interval (95% CI) 1.01-1.48) more likely of having a baby with any birth defect. High exposure was also strongly associated with an increased risk of having a baby with a cardiovascular defect (62% increased risk). Low birth weight and prematurity were also assessed; however these outcomes were not associated with an increased risk through an increase in exposure. Following on from this analysis, a population risk assessment model was developed for DBPs in high exposure environments. This involved a three step process: (i) Firstly a questionnaire-based validation and reliability study was used to assess water consumption patterns of a population of pregnant women in Perth. (ii) Secondly a prediction model for teratogenic burden of DBPs in Perth was developed, related to the exposure patterns of the population of pregnant women involved in the validation and reliability study. (iii) Finally, combining the information collected in (i) and (ii), along with the regression slope estimates for birth weight from the prevalence study (defined in Section 2.2.1), a dose-response model for THMs and birth weight was developed. Predictive simulations for birth weights at given THM levels were then conducted. It was estimated that pregnant women in Perth are exposed to between 0.3 – 4.10 µg/day ingested TTHM, and of this, the more toxic brominated forms accounted for between 0.27 – 3.69 µg/day. Based on a dose-response model used, birthweights calculated for the ‘hypothetical’ exposures ranged from 3403.2g for the highest exposure to 3503.5g in the lowest exposure, which is a difference of over 100g. Although the resulting reduction in birth weight is not extreme, there is still a significant reduction in birth weight present as exposure to TTHMs increases. This is the first doseresponse model to be developed to assess an adverse pregnancy outcome based on pregnant women exposure data, and will be a useful tool for assessing varying exposures throughout not only Australia but also throughout the industrialised world, where DBP exposure is highly prevalent.

In recent years, a compound N-nitrosodimethylamine (NDMA), a probable human carcinogen, has been identified as an emerging disinfection by-product (DBP) since its formation and detection were linked to chlorine-based disinfection processes in several water utilities in the U.S. and Canada. Numerous organic nitrogen compounds present in water may impact the formation of NDMA during disinfection. Amine-based water treatment polymers used as coagulants and flocculants have been suggested as potential NDMA precursors due to the presence of amine functional groups in their structures, as well as the possible presence of dimethylamine (DMA) residues in polymer products. To minimize the potential risk of NDMA associated with water treatment polymers, the mechanisms of how the polymers behave as NDMA precursors and their contribution to the overall NDMA formation under actual water treatment conditions need to be elucidated. This research involved a systematic investigation to determine whether amine-based water treatment polymers contribute to NDMA formation under drinking water and wastewater treatment conditions, to probe the involved reaction mechanisms, and to develop strategies to minimize the polymers NDMA formation potential. The investigation included five research tasks: (1) General screening of NDMA formation potential of commonly used amine-based water treatment polymers, (2) NDMA formation from amine-based water treatment polymers under relevant water treatment conditions, (3) Probing the mechanisms of NDMA formation from polyamine and PolyDADMAC, (4) Effect of water treatment processes on NDMA formation from amine-based water treatment polymers, and (5) Developing strategies to reduce polymers NDMA formation potential. Direct chloramination or chlorination of high doses of polymers in deionized water at longer than typical contact time was used in the general screening of the NDMA formation potential of water treatment polymers and in the studies to identify reaction mechanisms. On the other hand, realistic dosages of chloramines and polymers and contact time were used in simulating representative water treatment conditions to evaluate the contribution of polymers to the overall NDMA formation in real systems. On the basis of the study results, strategies were developed to reduce the NDMA formation potential of amine-based water treatment polymers, which include modification of polymer structures and treatment parameters.

Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2016.
Trihalomethanes are disinfection byproducts of chlorinated waters, and there is a growing interest to understand plant responses to organohalogens. This study investigates the effects of increasing trihalomethane dose on the physiology of tomato (Solanum lycopersicum) and determines whether the extent of physiological impacts of trihalomethane exposure on seedling radicle length, biomass accumulation, concentration levels of 12 key nutrients, oxidative stress, fatty acids and α-tocopherol content in membrane lipids of tomato correlated with either the number of bromine or chlorine atoms in the trihalomethane molecules. The 2 x 4 x 5 factorial experiment was laid out in CRD with four replications. Two cultivars of tomato were exposed to 4 levels of trihalomethanes (bromodichloromethane, bromoform, chloroform and dibromochloromethane) and 5 levels of concentration (0.0, 2.5, 5.0, 7.5, and 10.0 mg.L-1) in a green house. The decrease in seedling biomass and the inhibition of radicle growth increased with increasing trihalomethane concentrations in a dose dependent manner. Also, both these parameters decreased in response to an increase in the number of bromine atoms in the trihalomethane molecule. However, in growing plants the decrease in concentration levels of seven essential nutrients namely nitrogen (N), phosphorus (P), potassium (K), sulphur (S), copper (Cu), zinc (Zn) & boron (B) correlated to an increase in the number of chlorine atoms. Increase in trihalomethane dose also induced a decrease in all the above mentioned nutrients with the addition of manganese (Mn), although the decrease in P and S were not significant at P ≤ 0.05. The increase in trihalomethane dose induced an increase in oxidative stress parameters such as the total phenolic content, ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and lipid peroxidation. The increase in the above parameters correlated to an increase in the number of chlorine atoms, however, no such correlations were observed in superoxide dismutase (SOD) activity, general lipid peroxidation, α-tocopherol content and totalsoluble proteins. In plant membrane lipids, increase in the saturated fat hexadecanoic acid was observed in both tomato cultivars that correlated to the degree of chlorination in the trihalomethane molecule. The increase in α-linolenic acid stress signaling correlated with an increase in the degree of chlorination in only one tomato cultivar suggesting variable tolerance between cultivars to chemical action. Membrane lipids adjustments in tomato plants exposed to increasing trihalomethane dose were based on two factors; first the adjustments of membrane fluidity with the increase in plant sterols and fatty acids content and secondly, the increase in lipophyllic antioxidants such as phenols, quinones and α-tocopherol content. The phenolic lipophyllic antioxidant was tentatively identified to be 2,2’-methylenebis [6-(1,1-dimethylethyl)-4-methyl] phenol. In conclusion, the magnitude of plant responses to trihalomethanes is more dependent on the halogenation number of the molecule and less on its concentration.

The validation of UV reactors is currently accomplished by biodosimetry, in which the reactor is treated as a "black-box" and hence cannot account for the dependence of the dose delivery on the complex hydrodynamics and the spatial variation in UV intensity. Alternative methods, such as fluorescent microspheres as non-biological surrogates and computational fluid dynamics (CFD) simulations, have been developed; however, each method has its shortcomings. In this study, a novel technique for the spatial and temporal assessment of the hydrodynamics and the UV dose delivered and the link between these two factors in a lab-scale UV reactor using three dimensional laser induced fluorescence (3DLIF) is developed. This tool can also be utilized for the optimization of UV reactors and to provide data for validation of CFD-based simulation techniques. Regions of optimization include areas around the UV lamp where short-circuiting occurred, a longer inlet approach section that enhances the performance of the reactor by reducing short circuiting paths and a longer outlet region to provide greater mixing. 3DLIF allows real time characterization of mixing and dose delivery in a single lamp UV reactor placed perpendicular to flow by capturing fluorescence images emitted from a laser dye, Rhodamine 6G, using a high speed CCD camera. In addition to three-dimensional mixing, the technique successfully visualized the two-dimensional, transient mixing behaviors such as the recirculation zone and the von Karman vortices and the fluence delivery within the reactor, which has not been possible with traditional tracer test techniques. Finally, a decomposition technique was applied to the flow and fluence delivery based concentration data to reveal similar structures that affect these phenomena. Based on this analysis, changing the flow in the reactor, i.e. the Reynolds number, will directly affect the fluence delivery.

This research, involving a collaboration between Imperial College London and Anglian Water, and had the overall aim to understand the occurrence and fate of a wide range of disinfection by-products (DBPs) during drinking water distribution and to establish operational strategies to simultaneously control them in water supply systems. Therefore, the research is essentially centred on two main issues: i) improving our understanding of the impact of water quality and operational parameters on regulated and unregulated DBPs in water distribution networks, and ii) the validation of a prediction tool to proactively design and adapt operational practices to minimise DBPs. The research explored these issues through a series of experiments focused on the analysis of 29 DBPs upon chlorination and chloramination, under various water ages and water quality conditions, by sampling from four locations in four full-scale distribution systems in four sampling rounds and simultaneously running Simulated Distribution System (SDS) tests. This resulted in one of the most comprehensive databases of the occurrence and behaviour in distribution systems of regulated trihalomethanes (THMs), the likely-to-be-soon-regulated-in-the-UK haloacetic acids (HAAs), as well as unregulated haloacetonitriles (HANs) and haloacetamides (HAcAms) of potential health significance, and their individual species. For the first time, SDS tests were shown to be able to successfully predict the levels and speciation of HANs and HAcAms in chlorinated and chloraminated systems, by direct comparison with actual distribution water samples. The configuration of SDS tests addressed the spatial and temporal variation of the selected DBPs, indicating that even though THM concentrations significantly increase with water age (on average by ~54% between water ages of6-106 h) and present high seasonal dependence. together with HAAs. The latter, HANs, and HAcAms concentrations had fluctuations that resulted in less pronounced overall increases, with the two N-DBPs relatively unaffected by water temperature. To explore the impact of disinfectant alteration in distribution, free chlorine and chloramination were applied in the same real water samples in SDS tests. This showed that the implementation of chloramination minimises the formation not only of THMs and HAAs, but also HANs and HAcAms, though it shifts speciation towards more brominated HAAs, HANs and HAcAms species. Through this research, SDS tests can be recommended to water utilities to both estimate the concentrations of DBPs (those included in this study) in their supply systems and assess the effect of potential DBP minimisation strategies. The interesting behavioural patterns of HAcAms in distribution systems raised questions concerning their formation mechanisms and determining factors. Therefore, a laboratory study was conducted whereby chlorination and chloramination were applied to six model amide compounds to investigate their relative contributions as N-DBPs precursors, under a range of water quality conditions (pH, bromide dose, water age). The findings of this study suggest that the N-oxidation of amide structures, more evident in aromatic moieties, is a potential mechanism for HAcAms formation, which occurs completely separately from HAN hydrolysis. This suggests that if precursor removal is to be used as a treatment strategy for minimising HAcAms and HANs, the success in minimising these groups of N-DBPs may differ based on the relative success in removing their independent precursors.

This thesis studied the effect of chlorination disinfection by-products (CDBPs) in drinking water on the risk of developing pancreatic cancer. The study was based on the case-control component of the National Enhanced Cancer Surveillance System. Incident cases and frequency-matched population controls recruited between 1994 and 1997 from six Canadian provinces were used to estimate pancreatic cancer risks associated with exposure to CDBPs. Residence history collected from subjects was linked to two sources of water quality data to estimate historical exposure. The first source provided a lifetime average estimate of known exposure to trihalomethane (THM), bromodichloromethane (BDCM), and chloroform (TCM), while the second provided residence-specific estimates of THM exposure. Adjusted risk estimates were based on the most recent 30 years of exposure with missing data imputed using Observed Control Mean Imputation. Overall, no consistent significant increase (or decrease) in pancreatic cancer risks was observed with 30-year exposure to THM, BDCM, and TCM after adjusting for potential confounders.

The shortage in water resources have been observed all over the world. However, the safety of drinking water has been given much attention by scientists because the disinfection will react with organic matters in drinking water to generate disinfection by-products (DBPs) which are considered as the cancerigenic matters. Although much research has been carried out on the water quality control problem in DWDS, the water quality model considered is linear with only chlorine dynamics. Compared to the linear water quality model, the nonlinear water quality model considers the interaction between chlorine and DBPs dynamics. The thesis proposes a nonlinear model predictive controller which utilises the newly derived nonlinear water quality model as a control alternative for controlling water quality. EPANET and EPANET-MSN are simulators utilised for modelling in the developed nonlinear MPC controller. Uncertainty is not considered in these simulators. This thesis proposes the bounded PPM in a form of multi-input multi-output to robustly bound parameters of chlorine and DBPs jointly and to robustly predict water quality control outputs for quality control purpose. The methodologies and algorithms developed in this thesis are verified by applying extended case studies to the example DWDS. The simulation results are presented and critically analysed.

As the international standards for drinking water become more stringent and the health guideline values for currently regulated disinfection by-products (DBPs) decrease, the challenge increases for water utilities to produce water which conforms to the guidelines. In Australia, expanding populations, and drought in some areas, particularly Western Australia, have already resulted in scarcity of water in many urban and regional centres. As a result, water of more marginal quality must be utilised for potable purposes, and the variable and more concentrated natural organic matter (NOM) in these water sources makes the treatment, distribution, and disinfection processes increasingly difficult.While NOM itself does not appear to be harmful, when it reacts with disinfectants, some of the resulting DBPs have been found to be potentially harmful to human health. Due to concerns about these potential health effects, other disinfection methods aimed at reducing the major DBPs from chlorination, such as the trihalomethanes (THMs), have been investigated. Chloramination is increasingly being used as an alternative disinfection method to chlorination, because it has the advantage of producing only trace amounts of THMs and haloacetic acids (HAAs). However, chloramination can result in the formation of other DBPs, some of them newly identified and termed ‘emerging DBPs’, such as the N-nitrosamines, with many of the emerging DBPs being reported to be carcinogenic, mutagenic, and/or teratogenic. For the purpose of this Thesis, ‘emerging DBPs’ refers to DBPs which have little or no regulations or guideline values assigned to them.An effective approach to reducing the formation of potentially harmful DBPs is to remove the DBP precursors prior to the disinfection stage. For removal of dissolved organic carbon (DOC) as a DBP precursor, it is becoming increasingly common for ozone to be used as a pre-oxidant or intermediate oxidant during drinking water treatment. Ozone followed by biological activated carbon (BAC) filtration has been shown to improve water quality by removing a portion of the DOC, depending on the content of ozone-reactive DOC within the water source. However, in bromide-containing waters, ozonation can result in the formation of bromate, a potent carcinogen. Advanced oxidation processes (AOPs), which usually involve the addition of a combination of chemical oxidants and/or a source of UV light, are also attracting increasing interest as DOC removal techniques.

The main objective of this study was to conduct a systematic investigation of the disinfection by-products (DBPs) formation in low-bromide and low- specific ultraviolet absorbance (SUVA) waters and the control of DBP precursors by nanofiltration (NF) and ultrafiltration (UF) processes in such waters. To this end, firstly, the effect of bromide ion on the formation and speciation of DBPs was investigated. In fractionated Alibeykö
y source water, increasing bromide concentrations in NOM fractions increased concentrations of trihalomethanes (THMs), haloacetic acids (HAAs) and adsorbable organic halides (AOX) and resulted in a shift toward the formation of brominated species. Secondly, the impacts of SUVA and differential UV spectroscopy (&
#916
UV), which has been shown to correlate well with DBP formation has been elucidated in terms of DBP formation and speciation. Alibeykö
y and Karacaö
ren waters were fractionated employing various separation methods and it has been shown that SUVA did not correlate well with the formation and speciation of THMs and HAAs in tested low-SUVA waters. Similarly, no correlations were found among THMs/HAAs formations and &
#916
UV. Finally, the NOM rejection performances of NF and UF membranes were investigated. NF and UF membranes (<
2000 dalton) was found to be suitable for the removal NOM from surface waters having low SUVA and low bromide contents. While higher molecular weight (HMW) fraction was successfully rejected (>
90%) by all membrane types, lower molecular weight (LMW) fraction could be removed with ranging efficiencies from 1.5 to 30%. NF membranes provided DOC, UV254 absorbance, THM, and HAA reductions up to 90%.

There is much debate on the carcinogenic potential of disinfection by-products (DBP) in chlorinated water supplies. Until recently, epidemiological studies have been limited in their ability to examine accurately the risk of cancer with exposure to environmental carcinogens. This has largely been due to the long latency periods associated with cancer development, and the difficulties in accurately estimating chronic exposure. Although there is evidence, from predominantly case-control studies, of increased bladder cancer with exposure to chlorinated water supplies, the evidence is inconclusive. ¶ In an attempt to determine the carcinogenic potential of trihalomethanes (THMs) in chlorinated water, this study utilises DNA damage to bladder cells, evident as micronuclei, as a pre-clinical outcome measure. Using a pre-clinical marker helps overcome some of the limitations associated with long latency periods. The study improves on previous studies by estimating exposure to DBP at an individual level, and takes into consideration ingestion, inhalation and dermal exposure. ¶ A cohort study was undertaken in three Australian communities. The Bungendore (NSW) water supply was not chlorinated thereby providing a community unexposed to DBPs from chlorinated water. Canberra (ACT) and Adelaide (SA) had intermediate and relatively higher (but still within NHMRC guideline levels) of DBPs in the reticulation system. Trihalomethane levels in reticulated water (external dose) and in urine (internal dose) were used as exposure indices. As well, intake dose was computed by adjusting external dose for individual variations in ingestion and bathing. The primary outcome measure was the prevalence of micronuclei in bladder epithelial cells. A DNA index derived from flow cytometry was also used to estimate DNA damage in bladder cells. Associations between exposure and outcome were estimated using Poisson regression models, having identified and adjusted for interaction effects and confounders. ¶ A total of 529 participants were eligible to participate, of which 348 (65.8%) completed all aspects of the study. Analysis was limited to the 228 participants (65.53% of those who completed the study) who had slides suitable for micronuclei scoring. One hundred and forty three (63%) of the 228 participants were from the exposed communities, while 85 (37%) were from the unexposed community. This sample exceeded the estimated 50 per group required to detect a relative risk of 1.4, with a significance level of 0.05 and 80% power. ¶ External dose for total THM for the two chlorinated (exposed) communities ranged from 37.75 to 157.25 mg/l. Intake dose estimated by fluid intake diary ranged from 2.9 to 469.5 mg/l, while a retrospective questionnaire estimated intake dose to range from 0 to 409.4 mg/l. Internal dose (urine levels) of total THM for the same two communities ranged from 0 to 6.82 mg/l. Adjusted risk estimate for DNA damage to bladder cells (using the micronuclei assay) when total THM was assessed by available dose was 1.0002 (0.997 to 1.003), by intake dose estimated by fluid intake diary was 1.0001 (0.998 to 1.002), by intake dose estimated by questionnaire was 1.001 (0.999 to 1.003), and by internal dose was 1.05 (0.89 to 1.24). Using DNA index from flow cytometry as the outcome measure also did not identify significant associations, except when exposure was assessed as available dose of total THM (RR=1.0042; 1.0003 to 1.0081). ¶ The results suggest that THM levels are not significantly associated with DNA damage to bladder cell. This supports suggestions of THMs being non-genotoxic. Further work is required to assess the relationship between THM and the more mutagenic compounds, and to assess the carcinogenicity of the more mutagenic compounds at concentrations occurring in drinking water.

Source water quality plays a critical role in maintaining the quality and supply of drinking water, yet it can be negatively affected by human activities. In Pennsylvania, coal mining and treatment of conventional oil and gas drilling produced wastewaters have affected source water quality for over 100 years. The recent unconventional natural gas development in the Marcellus Shale formation produces significant volumes of wastewater containing bromide and has the potential to affect source water quality and downstream drinking water quality. Wastewater from coal-fired power plants also contains bromide that may be released into source water. Increasing source water bromide presents a challenge as even small amounts of bromide in source water can lead to carcinogenic disinfection by-products (DBPs) in chlorinated finished drinking water. However, bromide is not regulated in source water and is not removed by conventional drinking water treatment processes. The objective of this work is to evaluate the safe bromide concentration in source water to minimize the cancer risk of trihalomethanes - a group of DBPs - in treated drinking water. By evaluating three years of water sampling data from the Monongahela River in Southwestern Pennsylvania, the present analysis reached three conclusions. First, bromide monitoring for source water quality should be taken at drinking water intake points. Water sample types (river water samples vs drinking water intake samples) can lead to different water quality conclusions and thus affect regulatory compliance decision-making. Second, bromide monitoring at drinking water intake points can serve as a predictor for changes in heavily brominated trihalomethanes concentrations in finished water. Increasing bromide in source water can serve as an early warning sign of increasing formation of heavily brominated trihalomethanes and their associated cancer risks in drinking water. Finally, this work developed a statistical simulation model to evaluate the effect of source water bromide on trihalomethane formation and speciation and to analyze the changing cancer risks in water associated with these changing bromide concentrations in the Monongahela River. The statistical simulation method proposed in this work leads to the conclusion that the bromide concentration in source water must be very low to prevent the adverse health effects associated with brominated trihalomethanes in chlorinated drinking water. This method can be used by water utilities to determine the bromide concentration in their source water that might indicate a need for process changes or by regulatory agencies to evaluate source water bromide issues.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004.
Includes bibliographical references (leaves 106-124). Also available in electronic version. Access restricted to campus users.

The National Aeronautics and Space Administration (NASA) is considering the use of iodine for disinfection of recycled wastewater and potable water in the International Space Station (ISS). Like Chlorine and other halogen compounds, iodine can form disinfection by-products (DBPs) in the presence of organic compounds. Recycled wastewater sources proposed for reuse in the space station include laundry, urine, and humidity condensate. These contain large concentrations of iodine-demanding compounds, including phenol (Barkely et al., 1992). Therefore, the potential for the formation of iodine disinfection by-products (IDBPs) is of concern. Based on the characteristics of the ISS recycled wastewater sources and potable water treatment system, a series of experiments was designed to evaluate the formation of IDBPs under different experimental conditions. Studies were conducted by reacting various concentrations of iodine with phenol at pH 5.5 and 8.0.Iodine concentrations of 10 and 50 mg/L and phenol concentrations of 5 and 50 mg/L were used. Reactions were monitored for up to 32 days for the formation of IDBPs. All reactions were maintained at 20 C in dark. High Performance Liquid Chromatography (HPLC) and Gas Chromatography/Mass Spectrometry (GC/MS) were used for identification and quantitative analysis of phenolic compounds. Spectrophotometry was used to monitor the iodine concentrations. Falvor Profile analysis (FPA) method was used to evaluate the odor characteristics of the phenolic compounds. Reactions of iodine with phenol resulted in the formation of the following by-products: 2-iodophenol, 4-iodophenol, diiodophenols, and 2,4,6-triiodophenol. Most reaction conditions studied resulted in the formation of all or some of the specified iodophenols. The initial mass ratio of iodine to phenol was the major determining factor in the concentrations and types of by-products formed. The IDBPs were formed within one hour after initiation of the reactions. Extended reaction times did not lead to significant increases in the concentration of IDBPs. Under most reaction conditions, mono-subsituted phenols were detected at significantly higher concentrations than di-substituted phenolic compounds; triiodophenol was the major by-product when iodine:phenol mass ratio was 10:1. The greatest number of IDBPs were formed when reaction solutions consisted of 1:1 mass ratio of iodine to phenol. FPA panel indicated the odor threshold concentrations for phenol, 2-iodophenol, and 4-iodophenol were 5 mg/L, less than 1 ug/L, and 1 mg/L respectively. The most common odor descriptions for all these compounds were "chemical", "phenolic", and "medicinal".
Master of Science

Thesis (Ph. D.)--Michigan State University. Dept. of Civil and Environmental Engineering, 2006.
Title from PDF t.p. (viewed on June 19, 2009) Includes bibliographical references. Also issued in print.

The antibacterial agent, triclosan, is widely used in many household personal care products, and it has recently been detected in wastewater treatment plant effluents and in source waters used for drinking water supply. Accordingly, the reactivity of triclosan with the disinfectants used in wastewater treatment and in the production of potable water is of interest. Monochloramine is used as an alternative disinfectant in drinking water treatment to minimize production of regulated disinfection by-products. This study examined the reactions between triclosan and monochloramine and involved analysis of monochloramine and triclosan decay and product formation under drinking water treatment conditions over a pH range of 6.5 to 10.5. Monochloramine decay in the presence of triclosan was measured relative to monochloramine auto-decomposition in the absence of triclosan using UV-VIS spectrophotometry. Experimental results showed that the monochloramine auto-decomposition intermediates, free chlorine and dichloramine, are responsible for a majority of the observed triclosan decay and product formation. A kinetic model for monochloramine auto-decomposition was modified to include terms and rate coefficients for the reactions of triclosan with monochloramine (k = 90.4 M^-1h^-1), free chlorine (k = 1.94×10⁷ M^-1h^-1), and dichloramine (k = 2×10⁵ M^-1h^-1), and was able to predict triclosan and monochloramine decay. It was determined that the reactions of dichloramine and free chlorine with triclosan were 10³ and 10⁵ times faster, respectively, than the reaction of monochloramine with triclosan. The products of these reactions, detected using GC-MS, included three chlorinated triclosan intermediates, 2,4-dichlorophenol, and 2,4,6-trichlorophenol. Low levels of chloroform were detected at pH values of 6.5 and 7.5.
Master of Science

Aboard the International Space Station, potable water will likely be produced from recycled wastewater. The National Aeronautic and Space Administration (NASA) plans to use iodine as a disinfectant, and, consequently, the formation of iodinated disinfection by-products (IDBPs) requires investigation. Objectives of this research were to determine possible precursors of IDBPs, identify IDBPs formed, and apply flavor profile analysis (FPA) as a tool to evaluate water qaulity. Experiments were performed by separately reacting iodine with each of the following organic compounds: methanol, ethanol, 1-propanol, 2-propanol, 1-methoxy-2-propanol, acetone, and formaldehyde. NASA previously identified all of these compounds in wastewater sources under consideration for recycling into potable water. Experiments were performed at pH 5.5 and 8, iodine concentrations of 10 and 50 mg/L, and organic concentrations of 5 and 50 mg/L. Gas chromatography/mass spectrometry was used to identify and monitor the concentrations of organic species. Spectrophotometry was used to monitor the iodine concentration. Acetone was the only compound identified as an IDBP precursor and it reacted to produce iodoacetone and iodoform. Concentrations of iodoform from 0.34 mg/L to 8.637 mg/L were produced at conditions that included each pH level, iodine concentration, and acetone concentration. The greatest iodoform concentration was produced at pH 8 from 50 mg/L of iodine and acetone. FPA indicated that the odor threshold concentration (OTC) of iodoform was 1.5 ug/L, and the OTC of iodine was 500 ug/L. Both iodine and iodoform have medicinal odors, making it difficult to distinguish each compound when present in a mixture.
Master of Science

Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.
Title from electronic title page (viewed Mar. 26, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Epidemiology." Discipline: Epidemiology; Department/School: Public Health.

Chlorine is the most widely used disinfectant for drinking water treatment. Chlorine canreact with natural organic matter (NOM) in water sources resulting in the formation of potentially carcinogenic disinfection by-products (DBPs). The most common DBPs measured in chlorinated drinking water distribution systems are trihalomethanes (THMs) and haloacetic acids (HAAs). In 2005, the City of Kamloops, British Columbia upgraded the drinking water treatment system to ultrafiltration membrane treatment. The objective of this study was to determine the extent to which upgrades to a drinking water treatment system, specifically, implementation of an ultrafiltration treatment process, impacted DBP formation within a distribution system. This study used a two-phase research approach. Phase I of the study was a distribution system monitoring program that collected water samples and physical and chemical information using data loggers at five sampling sites within the distribution system. Phase II of the study used bench-scale simulations that modeled DBP formation using a flow-through reactor system, the material-specific simulated distribution system (MS-SDS), constructed of pipe material resurrected from the City of Kamloops distribution system. Phase I results suggested that implementation of the ultrafiltration treatment process and accompanying treatment system upgrade was not effective at reducing the concentration of DBPs delivered to consumers. Concentrations of THMs remained relatively constant at sampling sites, while concentrations of HAAs increased following implementation of the ultrafiltration treatment process. The increase in HAA formation was likely due to an increase in retention time of the water within the distribution system following implementation of the ultrafiltration treatment process, rather than due to the treatment process itself. The results of this study are consistent with previous work on South Thompson River water DBP precursors, which suggested that THM and HAA precursors of this source water are small and hydrophilic, and therefore cannot be removed by ultrafiltration processes. Phase II results showed that the MS-SDS was more representative of distribution system c onditions than traditional glass bottles to estimate DBP formation. It is recommended that the MS-SDS be used in parallel with a simultaneous distribution system monitoring program to estimate distribution system retention times from THM and HAA concentrations.

Els subproductes de desinfecció de l’aigua són tots aquells productes resultants de reaccions químiques entre la matèria orgànica i inorgànica de l’aigua i els agents químics utilitzats en la seva desinfecció. Fins aquest moment, s’han identificat més de 600 classes de DBP en aigües tractades arreu del món. Estudis epidemiològics mostren una forta relació entre la presència d’aquests productes i la incidència de càncer, però fins ara no s’han pogut identificar les espècies responsables d’aquests efectes. La majoria de protocols in vitro utilitzats per establir la genotoxicitat i carcinogenicitat de cada classe de DBP s’han basat en exposicions agudes a concentracions relativament altes d’aquestes espècies químiques, seguits d’una extrapolació a concentracions més baixes. La manca d’una metodologia més sistemàtica per analitzar el potencial carcinogènic dels DBP ha generat buits a la literatura que s’han de resoldre. A més, els mètodes utilitzats fins ara han dut a resultats que no reflecteixen un escenari real d’exposició. En aquesta tesi proposem l'aplicació d'una metodologia in vitro d'avaluació de riscos carcinogènics basada en l'avaluació d'una àmplia gamma de marcadors de transformació cel·lular, mitjançant la qual s'analitza el potencial carcinogènic i els efectes a llarg termini de dos grups de DBP, HNM i HAA. El principal avantatge d'aquesta metodologia és la possibilitat d'analitzar exposicions prolongades a concentracions més realistes dels DBP, establint així un model d'exposició més realista. Els resultats del nostre primer estudi indiquen que els HNM no són capaços d'induir una transformació tumoral en cèl·lules pulmonars humanes després d'una exposició de 8 setmanes, ni d’induir o augmentar el creixement tumoral. L'avaluació de fibroblasts en contacte amb el CM de cèl·lules exposades, emulant l'estroma tumoral, mostra que en el període d'exposició les cèl·lules estromals no adquireixen la capacitat d'induir el creixement tumoral. L'avaluació de la secreció de MMP determina que ni les cèl·lules exposades ni les cèl·lules estromals podrien secretar aquestes proteïnases que facilitarien la migració tumoral i la metàstasi. El nostre segon estudi mostra que encara que els tres mono-HAA són capaços d'induir dany oxidatiu després d'exposicions agudes, les concentracions no citotòxiques no serien genotòxiques després de 8 setmanes d'exposició. Per contra, les cèl·lules exposades a llarg termini a concentracions no citotòxiques dels HAA desenvolupen resistència als agents oxidants de l'ADN. D’altra banda, l'avaluació in vitro a llarg termini de la carcinogenicitat dels HAA demostra que no poden iniciar una transformació tumorigènica en cèl·lules urotelials. En conjunt, podem concloure que l'ús d'assajos de transformació cel·lular, basat en exposicions prolongades a baixes concentracions, emulant un escenari d'exposició més realista, és una manera més consistent d'avaluar la carcinogenicitat dels DBP. A més, les anàlisis realitzades en aquesta Tesi suggereixen que l'augment de la incidència de càncer vinculat a l'exposició als DBP no pot atribuir-se als HNM ni als HAA.
Disinfection by-products are all those chemical species that are formed during the disinfection of water. To date, more than 600 species of DBPs have been identified in chemically-disinfected waters all over the world. Although epidemiological studies show a clear link between cancer, especially bladder cancer, and DBPs exposure, none of the individual species alone has shown sufficient carcinogenic potency to account for the increased cancer risk. To date, several different models and protocols have been used, attempting to establish the specific genotoxic and carcinogenic properties of individual DBP species. Still, most in vitro hazard evaluations have focused on acute exposures to relatively high concentrations of these chemicals, followed by an extrapolation to low concentrations. The lack of a more systematic methodology to assess the carcinogenic potential of DBPs, generated gaps in the literature that must be resolved. Additionally, current assessment methods led to results that do not reflect real exposure scenarios. In this Thesis we propose the application of an in vitro carcinogenic risk assessment methodology based on the evaluation of a wide range of cell transformation markers, whereby we analyse the carcinogenic potential and long-term effects of two DBPs groups, HNMs and HAAs. The principal advantage of such methodology is the possibility to analyse prolonged exposures to more realistic concentrations of DBPs, thus, setting a more realistic exposure model. Results from our first study indicate that HNMs are not capable of inducing a tumoural transformation in human pulmonary cells after an 8 weeks’ exposure, neither to prompt exposed cells to induce or enhance tumoural growth. The evaluation of fibroblasts grown in contact with the CM of exposed cells, emulating the tumoural stroma, showed that in the exposure period stromal cells did not acquire the capacity to induce tumoural growth. Evaluation of MMPs secretion determined that neither exposed cells nor stromal cells could secrete these proteinases that would facilitate tumoural migration and metastasis. Our second study showed that although all three mono-HAAs appeared capable of inducing oxidative DNA damage after acute exposures, non-cytotoxic concentrations do not appear to be genotoxic after 8 weeks of exposure. On the contrary, cells long-term exposed to non-cytotoxic concentrations of the HAAs developed resistance to DNA-oxidising agents. In vitro long-term carcinogenicity assessment of HAAs proved them unable to initiate a tumorigenic transformation in urothelial cells neither in cells emulating the tumoural stroma. In addition, in any case cells were capable of inducing nor enhancing tumoural growth. Altogether, we conclude that the use of cell transformation assays, based on prolonged exposures to low concentrations, emulating a more realistic exposure scenario, is a more consistent manner to assess the carcinogenicity of DBPs. Additionally, analyses performed in this Thesis suggest that the increased cancer incidence linked to DBPs exposure cannot be attributed to HNMs nor HAAs.

Disinfection is an essential process in the treatment of municipal wastewater before the treated wastewater can be discharged to the environment. Hillsborough County's Northwest Regional Water Reclamation Facility (NWRWRF) in Tampa, Florida, currently uses ultraviolet (UV) light for disinfection. However, this method has proven expensive to implement and maintain, and may not be effective if the light transmission is poor. For these reasons, Hillsborough County is considering switching from UV light to sodium hypochlorite for disinfection. However, hypochlorite (chlorine) disinfection has disadvantages as well, such as the production of disinfection by-products (DBPs) such as trihalomethanes (THM) and haloacetic acids (HAAs), which may have adverse impacts on the quality of surface waters that receive the treated wastewater. Therefore, the objectives of this research are (1) to compare NWRWRF typical operating conditions and water quality to those of two nearby facilities (River Oaks and Dale Mabry Advanced Wastewater Treatment Plants) that currently employ chlorine disinfection, (2) to determine the chlorine demand of treated effluent from NWRWRF, (3) to quantify the DBP formation potential of treated effluent from NWRWRF, and (4) to determine the effects of temperature, reaction time, and chlorine dose on chlorine demand and THM formation. To inform laboratory experiments, the quality of final effluent was monitored at NWRWRF and at two nearby wastewater treatment plants that currently use hypochlorite for disinfection. At these two facilities, pH of 7.0-8.0, chemical oxygen demand (COD) of 12-26 mg/L, alkalinity of 200-250 mg/L as CaCO3, chlorine residual of 1.5-6.0 mg/L, and total trihalomethanes of 100-190 ix μg/L (mostly chloroform) were observed. Conditions at NWRWRF were similar to those at Dale Mabry and River Oaks AWWTP, suggesting that chlorine demand and THM formation at NWRWRF would be similar to those at the two AWWTP, if chlorination is to be used. THM experimental results agreed with this suggestion. Chlorine dose and temperature effects on the free chlorine residual and THMs production in NWRWRF filtered wastewater effluent were determined. Filtered effluent was collected and transported to USF laboratory where it was tested for 3 different chlorine doses (6 mg/L, 9 mg/L and 12 mg/L as Cl2) and 3 different temperatures (16°C, 23°C, and 30°C) at 7 different contact times (15, 30, 45, 60, 75, 90, and 120 min) in duplicate. The total number of batches prepared was: 3 different chlorine doses × 3 different temperatures × 7 different reaction times = 126 reactors. According to Florida Administrative code 62-600.440, total chlorine residual should be at least 1 mg/L after a contact time of at least 15 min at peak hourly flow. Also, according to Florida Administrative code 62-600.440, if effluent wastewater has a concentration of fecal coliforms greater than 10,000 per 100 mL before disinfection, FDEP requires that the product of the chlorine concentration C (in mg/L as Cl2) and the contact time t (in minutes) be at least 120. Results showed that free chlorine residual was always above 1 mg/L in 15 min contact time for all chlorine doses and temperatures tested in this thesis. However, to be conservative, thesis conclusions and recommendations were based on the more stringent regulation: C*t ≥ 120 mg.min/L, assuming that the number of fecal coliform in NWRWRF wastewater effluent exceeds 10,000 per 100 mL prior to disinfection. The analysis showed that free chlorine residual for 6 mg/L was below the FDEP standard at all temperatures. At 16 °C and 23 °C, chlorine doses of 9 and 12 mg/L resulted in an appropriate free chlorine residual above the FDEP standard. However, a chlorine dose of 12 mg/L was resulting in high residual, which means high THM would be expected. Therefore, at 16 x and 23°C, 9 mg/L would be preferable. At 30 °C, only the chlorine dose of 12 mg/L met the standard at all contact times. As expected, free chlorine residual decreased with an increase in temperature from 23°C to 30°C. Surprisingly, the residual at 16°C was lower than residual at 23°C. The production of THMs increased with higher contact time in all the experiments completed. Chlorine dose didn't have an effect on THM formation at 23°C, but it did at 30°C and 16°C, where THM concentrations were generally higher with the increase of chlorine dose. Temperature effect was noticed in most of the experiments, where THM production was usually higher at higher temperatures, except some cases where formation was similar for different temperatures. Chloroform, dichlorobromomethane, dibromochloromethane production ranges were respectively: 20-127 μg/L, 18-59 μg/L, and 3-7 μg/L. Bromoform concentrations were not observed in this experiment at any temperature or chlorine dose. According to Florida Administrative code 62-302.530, Criteria for Surface Water Quality Classifications, the Florida Department for Environmental Protection (FDEP) set the following limits for THM concentrations in wastewater effluent to be as the following; 470 μg/L for chloroform, 22 μg/L for dichlorobromomethane, 34 μg/L for dibromochloromethane, and 360 μg/L for bromoform. Experimental results on NWRWRF filtered effluent showed that only dichlorobromomethane exceeded the limits set by FDEP at about 30 min contact time for all temperatures and chlorine doses tested. However, according to Florida Administrative code 62- 302-400, proposed changes to the code have set higher DCBM limit of 57 μg/L. Chlorination would be recommended at NWRWRF if the DCBM regulated limit increases to 57 μg/L. The recommended chlorine dose would be 9 mg/L for water temperatures around 16-23 °C and 12 mg/L for water temperatures around 30 °C

To mitigate microbial activity in swimming pools and to assure hygienic safety for bathers, pool systems have a re-circulating water system ensuring continuous water treatment and disinfection by chlorination. A major drawback associated with the use of chlorine as disinfectant is its potential to react with organic matter (OM) present in pool water to form potentially harmful disinfection by-products (DBP). In this thesis, the treatment performance of different combinations of conventional and novel treatment processes was compared using a pilot scale swimming pool model that was operated under reproducible and fully controlled conditions. The quality of the pool water was determined in means of volatile DBPs and the concentration and composition of dissolved organic carbon (DOC). Further, overall apparent reaction rates for the removal of monochloramine (MCA), a DBP found in pool water, in granular activated carbon (GAC) beds were determined using a fixed-bed reactor system operated under conditions typical for swimming pool water treatment. The reaction rates as well as the type of reaction products formed were correlated with physico-chemical properties of the tested GACs.

Dibromoacetic acid (DBA) and bromochloroacetic acid (BCA) are prevalent disinfection by-products of drinking water known to produce defects in spermatogenesis and fertility in adult rats. Previous work in our laboratory demonstrated that BCA compromises both the fertility of cauda epididymal sperm and SP22, a sperm membrane protein highly correlated with the fertility of these sperm. Herein, we administered DBA and BCA, individually and in combination, to determine whether levels of SP22 on sperm and fertility were diminished in an additive fashion. Moreover, we wished to validate an immunoassay for quantitation of SP22 to replace the tedious two-dimensional (2D) gels quantitation. The initial study consisted of 8 treatment groups and a water vehicle control group, on which animals were exposed by oral gavage daily for 14 days. BCA was administered alone at 1.6, 4, and 8 mg/kg, and DBA was given in equimolar fashion at 2, 5, and 10 mg/kg. BCA and DBA were also given as two binary mixtures: 1.6 mg/kg BCA + 2 mg/kg DBA and 4 mg/kg BCA + 5 mg/kg DBA. Proximal cauda epididymal sperm membrane proteins (30 ìg) were resolved following concentration/desalting in 2D gels under denaturing conditions (2D SDS-PAGE) and the SP22 protein was quantified. In addition, SP22 was quantified by enzyme-linked immunosorbant assay (ELISA). Full length rat recombinant SP22 (rSP22) was used to generate a standard curve and affinity purified sheep anti-rSP22 was used as primary antibody. The ED50 for the decrease in SP22 quantified by 2D SDS-PAGE for DBA and BCA was 7.15 and 4.61 mg/kg. The ED50 for the decrease in SP22 quantified by ELISA for DBA and BCA was 8.10 and 5.93 mg/kg. The second study consisted of 2 and 4 mg/kg DBA, 1.6 and 3.2 mg/kg BCA, and a 2 mg/kg DBA + 1.6 mg/kg BCA mixture. In this study proximal cauda sperm were also used for in utero insemination to assess fertility. The ED50 for the decrease in fertility for DBA and BCA was 3.5 and 2.7 mg/kg. Immunostaining for SP22 in the testis revealed staining of both round and elongating spermatids and decreased staining in testes exposed to the DBA + BCA mixture. An evaluation of SP22 in testicular parenchyma was also performed by ELISA and Western blotting. Both evaluations revealed a treatment-related decrease in SP22. For either the 2D SDS-PAGE or ELISA quantitation of SP22 on sperm or the fertility of sperm, additivity or synergy is indicated. Finally, the correlation between SP22 levels measured by ELISA versus fertility was r2=0.74, compared to 0.82 for SP22 levels measured by 2D SDS-PAGE versus fertility, suggesting the ELISA could be used to supplant the time-intensive SDS-PAGE.

Chlorine is broadly used for water disinfection at the final stage of water treatment because of its high performance to inactivate pathogenic microorganisms, its lower cost compared to other well-known disinfectants and its simple operational needs. However, reaction of chlorine with a wide range of organic and inorganic substances in water causes its decay and formation of chlorinated by-products, which are in some cases carcinogenic and harmful to human health. The major challenge is balancing the risk from these with the cost of operation needed to mitigate the impact. These challenges highlights the importance of having a robust modelling approach for chlorine decay in bulk water as a pre-required step to model the chlorine decay and formation of its by-products in the whole distribution system.In this study, initially, a comprehensive literature review was conducted to investigate and evaluate all existing modelling approaches for chlorine decay prediction especially in bulk water. Among all existing modelling schemes, three models were paid more attention due to their popularity and/or fundamentally valid background. They are first order model, second order model and parallel second order model.During the literature review, comparing the effectiveness of the second order model (SOM) proposed by Clark (1998) with the parallel second order model (PSOM) offered by Kastl et al., (1999), the author found that these two models are both fundamentally sound, although the PSOM had better capability in terms of data fitting, and representing the chlorine decay behaviour is much better than SOM. However, non-existence of analytical solution for PSOM was found to be the major negative point for wide adaptation of PSOM compared to SOM.Trying to understand the basic principles of both models, it was understood that the formulation of SOM was genuine and the researchers who claimed that Clark (1998) made a mistake in deriving the analytical solution were proved wrong. This resulted in having the first publication as a comment in Water Research (Fisher et al., 2010b; Appendix A3).Further study was performed on how SOM was formulated and attempts were made to apply the same methodology to PSOM in order to arrive at an analytical solution. Consequently, making a reasonable assumption, an analytical solution for the parallel second order model was formulated and evaluated against the existing numerical method.As the case study of this research, initially, the previous chlorine decay data from Pilbara Water Treatment Plant was fitted to a first order reaction scheme and it was proved that the data did not comply with it. This was an expected result and the need for other model was validated. For further analysis, fresh water samples were collected from Pilbara Water Treatment Plant to perform chlorine decay tests.Temperature effect on the behaviour of chlorine decay in the bulk water was investigated by integrating Arrhenius equation with PSOM. Three methods of temperature analysis were compared and the best one was recommended for practical application. It was shown that the model was capable enough to properly display the chlorine decay profile when temperature varies.The thesis consists of eight chapters. In chapter 1, a brief description of the research background and the overall objectives of the research are given. Chapter 2 focuses on providing a comprehensive literature review about all involved aspects as well as chlorine decay modelling background. Chapter 3 discusses the methodology and analytical methods for conducting laboratory experiments. Chapter 4 gives a prove that the first order decay model does not show accurate results for chlorine decay prediction and the parallel second order model is much more accurate in predicting chlorine concentration. In Chapter 5, the main part of this research, an analytical solution for the parallel second order model is developed. Chapter 6 evaluates the effectiveness of the parallel second order model against the first and second order model. Within chapter 7, temperature effect on the chlorine decay behaviour and the selected modelling approach is evaluated and chapter 8 gives a brief conclusion and recommendation.

Orientador: Ruben Bresaola Júnior
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: A presente pesquisa teve por objetivo avaliar, em escala de laboratório, a formação de subprodutos da desinfecção (SPD), aldeídos (ALD) e trialometanos (THM), originados a partir da oxidação em soluções contendo ácidos húmicos na presença ou não de íons brometo, sob a ação do cloro livre, sob diferentes concentrações e tempos de contato. A técnica analítica utilizada foi a extração líquido-líquido e cromatografia gasosa com detector de captura de elétrons, a qual proporcionou a separação dos SPD originados em espécies: formaldeído, acetaldeído, glioxal, metilglioxal, clorofórmio, bromodiclorometano, dibromoclorometano e bromofórmio. A presença de íons brometo proporcionou maiores concentrações de ALD totais (TALD) e THM totais (TTHM), sob o tempo de contato de 12 h e 24 h, respectivamente. A variação de concentração de íons brometo de 0,50 para 2,00 mg L?1, promoveu uma depreciação na concentração de TALD em 12 h e uma inversão nas concentrações das espécies predominantes que existiam na ausência dos íons. A inversão nas concentrações das espécies predominantes de THM que existiam na ausência dos íons também foi presenciada, sendo que prevaleceram as espécies bromadas em detrimento das cloradas. Os resultados com íons brometo indicaram a possibilidade da existência de reações de oxidação competitivas para cada grupo de SPD e discutidas no trabalho. A remoção dos SPD foi realizada por adsorção mediante a utilização de carvão ativado em pó (CAP) em diferentes dosagens e com tempos de detenção do CAP de 60 e 120 min, seguido de simulação, em laboratório, do tratamento convencional de água, utilizando-se o sulfato de alumínio como coagulante. Os resultados destes ensaios realizados demonstraram remoções da ordem de 77% para os aldeídos totais, empregando-se dosagem de 30 mg L?1 de CAP e de 86% para os THM totais, empregando-se dosagem de 100 mg L?1 do mesmo, ambas as remoções sob tempo de detenção de 60 min. Os resultados de remoções de THM totais proporcionaram a adequação da água nos limites estabelecidos pela legislação brasileira e permitiram realizar simulações de custo do CAP a ser utilizado nas estações de tratamento de água
Abstract: The present research was to evaluate, in laboratory scale, the formation of disinfection byproducts (DPB), aldehydes (ALD) and trihalomethanes (THM), originated from the oxidation in solutions containing humic acids in the presence or not of ions bromide, under the action of free chlorine, under different concentrations and timing contact. The analytical technique used was the extraction liquid-liquid and gás chromatography with electrons detector capture, which provided the separation of DPB originated in species: formaldehyde, acetaldehyde, glyoxal, methyl-glyoxal, chloroform, bromodichloromethane, dibromochloromethane and bromoform. The presence of íons bromide gave higher concentrations of total ALD (TALD) and total THM (TTHM), under the time contact of 12 h and 24 h, respectively. The variation in the concentration of íons bromide from 0,50 to 2,00 mg L?1, caused depreciation in the concentration of TALD and a reversal in concentrations of predominant species that existed in the absence of ions. The reversal in concentrations of the THM predominant species that existed in the íons absence was also seen, and the brominated species prevailed at the detriment of chlorinated ones. The results with ions bromide indicated the possibility of the existence of competitive oxidation reactions for each group of DPB and it was discussed on the work. The removal of DPB was performed by adsorption using powdered activated carbon (PAC) in different dosages and with times of detention of PAC of 60 and 120 min, followed by simulation of the conventional water treatment, in the laboratory, using aluminum sulphate as coagulant. The adsorption test results, followed by coagulation, flocculation, sedimentation and filtration, showed removals of the order of 77% for TALD, using dosage of 30 mg L?1 PAC, and 86% for TTHM, using dosage of 100 mg L?1 of the same, both removals under detention time of 60 min. The total THM removal results gave the adequacy of water within the limits established by Brazilian legislation and allowed the realizations of simulations of cost of PAC to be used in water treatment
Mestrado
Saneamento e Ambiente
Mestre em Engenharia Civil

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016.
Poultry slaughterhouse wastewater (PSW) contains organic matter that can be degraded by microorganisms. Such matter can further be used by the microbial community as a nutrient source for growth. Moreover, this type of wastewater also contains a high quantity of particulate matter, lipids and proteins, including antimicrobial compounds such as triclosan (TCS) and trichlorocarbanilide (TCC) used during cleaning and sanitising of processing facilities. Lipids and particulate matter lead to clogging of pipes and fouling of diffusers in the wastewater treatment plants (WWTPs). To overcome this problem, a pre-treatment system such as a dissolved air flotation system (DAFs) in which synthetic flocculants are used, is commonly used prior to the biological treatment of the wastewater. Synthetic flocculants add to the environmental burden associated with the use of synthetic compounds, particularly when these compounds are used in WWTPs. This study focused on the reduction of suspended solids, lipids and proteinaceous matter using a bioflocculant- supported DAF for the treatment of PSW.

Cilj ovog rada bio je da se u laboratorijskim uslovima ispitaju efekti odabranihunapredenih procesa oksidacije (Fenton proces, ozonizacija, TiO2-katalizovana ozonizacija,perokson proces i TiO2-katalizovan perokson proces) i koagulacije na sadržaj i strukturuprirodnih organskih materija u vodi, kao prekursora dezinfekcionih nusprodukata hlora.Karaterizacija POM frakcionisanjem pre i nakon navedenih oksidacionih tretmana ikoagulacije izvršena je u cilju ispitivanja mehanizama oksidacije i uklanjanja POM, kao iutvrdivanja promene reaktivnosti prekursorskog materijla DBP (trihalometana i halosircetnihkiselina, kao najviše zastupljenih DBP, i haloacetonitrila, hlorpikrina i haloketona, kaonedovoljno istraženih, visoko prioritetnih „DBP u razvoju“).Analizom hemijskih karakteristika prirodnog matriksa utvrdeno je da voda sadrživisoke koncentracije prirodnih organskih materija (DOC sirove iznosi 9,92±0,87 mg/L) uzdominaciju materija hidrofobnog karaktera (14% huminskih i 65% fulvinskih kiselina). Uslucaju sintetickog matriksa (sadržaj DOC 11,2±0,37 mg/L) zastupljena je samo frakcijahuminske kiseline, te je iz tog razloga sinteticki matriks znatno hidrofobniji u odnosu naprirodni. Veci stepen hidrofobnosti sintetickog matriksa u poredenju sa prirodnim matriksom,rezultovao je i vecim sadržajem prekursora najzastupljenijih dezinfekcionih nusprodukatahlora, THM i HAA. Vrednosti za PFTHM iznose 438±88,2 μg/L za prirodni matriks,odnosno 3646±41,3 μg/L za sinteticki matriks, dok PFHAA prirodnog matriksa iznosi339±68,9 μg/L, odnosno 559±20,5 μg/L za sinteticki matriks. Sadržaj HAN, CP i HK jeznatno niži u poredenju sa prekursorima THM i HAA. PFHAN iznosi 3,65 μg/L za prirodni,odn. 7,98 μg/L za sinteticki matriks, dok prekursori CP nisu detektovani. Prekursori HK suzastupljeni samo u strukturi POM prirodnog matriksa i PFHK iznosi 46,9±5,08 μg/L.Hidrofoban materijal, kao dominantan u strukturi POM ispitivanih matriksa, je ujedno iosnovni prekursorski materijal THM i HAA, dok su prekursori haloacetonitrila i haloketona unavecoj meri zastupljeni u hidrofilnoj frakciji.Ispitivanjem uticaja Fenton procesa na sadržaj POM, pri optimalnim reakcionimuslovima (pH 5, reakciono vreme od 15 min. i brzina mešanja 30 o/min), postignuto je uzavisnosti od primenjene doze Fe2+, molarnog odnosa Fe2+ i H2O2 i matriksa 80-95%smanjenja saržaja DOC, 70-99% PFTHM, 37-92% PFHAA. Kao posledica uklanjanja POMoksidaciojom i koagulacijom, zabeležene su blage fluktuacije u sadržaju prekursora HAN, CPi HK.Ispitivanjem uticaja ozonizacije u vodi pri razlicitim pH na sadržaj i strukturu POMutvrdeno je da je ozonizacija u baznoj sredini efikasnija za uklanjanje POM u odnosu naozonizaciju u kiseloj sredini. Katalizovanje procesa ozonizacije primenom TiO2 u vodirazlicitim pH unapreduje smanjenje sadržaja kako ukupnih organskih materija, tako ispecificnih prekursora DBP u poredenju sa ozonizacijom. Najefikasnije smanjenje sadržajaPOM postignuto je TiO2-O3 procesa u baznoj sredini primenom 3,0 mg O3/mg DOC i 1,0 mgTiO2/L (30% DOC, 92-100% PFTHM, PFHAA, PFHAN i PFHK). TiO2-O3 proces pri svimpH vrednostima produkuje manji sadržaj CP u odnosu na ozonizaciju. Veca efikasnostprimenjenih procesa u smanjenju sadržaja POM sintetickog matriksa u odnosu na prirodniukazuju da je frakcija huminske kiseline podložnija oksidacionom tretmanu u odnosu nafulvinsku, kao dominantnu frakciju POM prirodnog matriksa. Kada je u pitanju mehanizamoksidacije POM ispitivanih matriksa, primenom ozonizacije i TiO2-O3 procesa, pri svim pHpostignuta je potpuna oksidacija frakcije huminske kiseline do fulvinske kiseline i hidrofilnihjedinjenja. U slucaju ozonizacije, sa povecanjem pH vrednosti sredine, usled povecaneprodukcije hidroksil radikala iz ozona, povecao se i udeo odnosno sadržaj DOC u hidrofilnojfrakciji ozonirane vode (86%-90%). Raspodela DOC nakon TiO2-O3 procesa pri svim pHvrednostima je oko 70% i 50% u hidrofilnoj frakciji prirodnog i sintetickog matriksa, redom.Frakcija koja se dominantno formira nakon navedenih oksidacionih tretmana je hidrofilna nekiselafrakcija. Frakcionisanjem POM nakon oksidacionih tretmana je utvrdeno da suprekursori THM i HAA kako hidrofobne aromaticne strukture, tako i hidrofilna polarnajedinjenja, dok je najreaktivniji prekursorski materijal HAN, CP i HK sadržan u hidrofilnojfrakciji POM.Uvodenjem H2O2 u proces ozonizacije (O3/H2O2 i iO2-O3/H2O2) u slabo baznojsredini (pH 7-7,5) postignut je još veci stepen oksidacije POM i povecanje udela hidrofilnihstruktura (oko 88%) ispitivanih matriksa u odnosu na ozonizaciju i iO2-O3 (oko 70%),primenom 3,0 mg O3/mg DOC; O3:H2O2=1:1 i 1,0 mg iO2/L. Povecanje sadržaja prekursoraTHM i HAA samo u slucaju prirodnog amtriksa posledica je povecanja reaktivnosti frakcijefulvinske kiseline nakon O3/H2O2 i iO2-O3/H2O2 procesa, u kojoj su ujedno i prekursori HKnajzastupljeniji. Najveci sadržaj azotnih DBP (HAN i CP) sadrži hidrofilna frakcija POM.Ispitivanjem kombinovanih procesa ozonizacije i TiO2-O3 i koagulacije utvrdeno je daoksidacioni tretmani imaju pozitivne efekte u uklanjaju POM koagulacijom. Maksimalnaefikasnost smanjenja sadržaja DOC od 32% postignuto je primenom 3,0 mg O3/mg DOC i200 mg FeCl3/L, dok su nešto niže doze ozona pogodne za uklanjanje prekursora DBP (80-89% PFTHM, PFHAA, PFHAN i PFHK, primenom 0,7-1,0 mg O3/mg DOC i 200 mgFeCl3/L). Prekursori CP koji se formiraju ozonizacijom zaostaju u vodi nakon koagulacije.Rezultati dobijeni tokom istraživanja ukazuju da se primenom razlicitih oksidacionih iunapredenih oksidacionih procesa može smanjiti sadržaj POM i prekursora DBP doodredenog stepena. Kao najefikasniji u uklanjaju kako ukupnih organskih materija, tako ispecificih prekursora DBP se pokazao Fenton proces. Kada su u pitanju unapredeni procesioksidacije zasnovani na primeni ozona, uvodenje katalizatora ili H2O2 kao oksidanta u procesozonizacije, kao i odabir optimalne pH vrednosti procesa može unaprediti oksidabilnostorganskih molekula. Pri tom, poznavanje mehanizama oksidacije POM iz razlicitih izvoraprimenom ozona i/ili hidroksil radikala, kao i mehanizma uklanjanja POM koagulacijommože se primeniti za odabir i optimizovanje odgovarajuceg procesa u tretmanu vode za pice,a u zavisnosti od kvaliteta sirove vode.
The aim of this work was to examine under laboratory conditions the effects ofcertain advanced oxidation processes (Fenton process, ozonation, TiO2-catalyzed ozonation, peroxone process and TiO2-catalyzed peroxone process) and coagulation on the content, structure and role of natural organic matter in water as the precursors of chlorine disinfection byproducts. The NOM was characterized by fractionation before and after these oxidation treatments and coagulation, in order to investigate NOM oxidation mechanisms and identify the changes in the reactivity of DBP precursor material (trihalomethanes and haloacetic acids, as the most abundant DBP, and haloacetonitriles, chloropicrin and haloketones, as underresearched, high priority “emerging DBP”). Through analysis of the chemical characteristics of the natural matrix, it was found that the water contains high concentrations of natural organic matter (raw water DOC was 9.92 ± 0.87 mg/L) dominated by substances with a hydrophobic character (14% humic and 65% fulvic acids). The synthetic matrix studied (DOC content of 11.2 ± 0.37 mg/L) contained only the humic acid fraction, and was therefore significantly more hydrophobic compared to the natural one. The greater degree of hydrophobicity in the synthetic matrix relative to the natural matrix resulted in a higher content of precursors of the most frequent chlorine disinfection byproducts, THM and HAA. The THMFP of the natural matrix was 438±88.2 mg/L, compared to 3646±41.3 mg/L for the synthetic matrix, while the HAAFP of the natural matrix was 339±68.9 mg/L, compared to 559±20.5 mg/L for the synthetic matrix. The contents of HAN, CP, and HK precursors were much lower than the THM and HAA precursors. HANFP were 3.65 mg/L for natural, and 7.98 mg/L for the synthetic matrix, whilst CP precursors were not detected. HK precursors were present only in the structure of the natural NOM matrix, with a HKFP of 46.9±5.08 mg/L. Hydrophobic material, as the dominant structure in the investigated NOM matrix, is the basic precursor material of THM and HAA, while the precursors of haloacetonitriles and haloketones are represented mostly in the hydrophilic fraction.Whilst examining the influence of the Fenton process on the NOM content, under optimal reaction conditions (pH 5, reaction time of 15 min and stirring speed of 30 rpm), depending upon the applied dose of Fe2+, the molar ratio of Fe2+ and H2O2, and the matrix, reductions in the DOC content of 80-95%, in the THMFP of 70-99%, and in the HAAFP of 37-92%, were achieved. As a result of removing NOM by oxidation and coagulation, mild fluctuations in the contents of HAN, CP and HK precursors were recorded. The investigation into the effects of ozonation at different pH levels on the content and structure of NOM has shown that ozonation under alkaline conditions is more effective at removing NOM than ozonation under acidic conditions. Catalyzing the ozonation process using TiO2 in water with different pH promotes the reduction of both total organic matter and specific DBP precursors in comparison with ozonation alone. The most effective NOM reduction was achieved using the TiO2-O3 process in alkaline conditions using 3.0 mg O3/mg DOC and 1.0 mg TiO2/L (30% DOC, 92-100% THMFP, HAAFP, HANFP and HKFP). The TiO2-O3 process produces lower amounts of CP at all pH values, relative to ozonation. The applied processes showed increased efficacy in reducing the NOM content of the synthetic matrix compared with the natural matrix, which shows that the humic acids fraction is more susceptible to oxidation treatments than the fulvic acids which are the dominant faction of the natural NOM matrix. Regarding the NOM oxidation mechanism in the investigated matrices, using ozonation and the TiO2-O3 process, complete oxidation of the humic acid fraction to fulvic acids and hydrophilic compounds was achieved at all pH levels. In the case of ozonation, increasing the pH in the matrix lead to an increase in hydroxyl radicals production from ozone, and the proportion or content of DOC in the hydrophilic fraction of ozonated water (86%-90%) increased. The distribution of DOC after the TiO2-O3 process at all pH values was about 70% and 50% in the hydrophilic fraction of the natural and synthetic matrices, respectively. The dominant fraction formed after the oxidation treatments was the hydrophilic non-acid fraction. By NOM fractionation after the oxidation treatments, it was shown that the THM and HAA precursors are hydrophobic aromatic structures and hydrophilic polar compounds, whilst the most reactive precursor materials for HAN, CP and HC are contained in the hydrophilic NOM fraction. Introducing H2O2 into the ozonation process (O3/H2O2 and iO2-O3/H2O2) in weak basic conditions (pH 7 to 7.5) enhances further the degree of NOM oxidation and increases the proportion of hydrophilic structures (88%) in the examined matrices in comparison to ozonation and iO2-O3 (about 70%), using 3.0 mg O3/mg DOC; O3:H2O2=1:1 and 1.0 mg iO2/L. An increase in the THM and HAA precursor contents occurred in the case of the natural matrix as a result of the increased reactivity of the fulvic acid fraction after the O3/H2O2 and iO2-O3/H2O2 processes, and HK precursors were also present. The highest content of nitrogen DBP (HAN and CP) was found in the hydrophilic NOM fraction. By examination of the combined processes of ozonation, TiO2-O3 and coagulation, it was shown that oxidative treatments have a positive effect on NOM removal by coagulation. A maximum efficacy in reducing DOC by 32% was achieved with 3.0 mg O3/mg DOC and 200 mg FeCl3/L, whereas slightly lower ozone doses are suitable for the removal of DBP precursors (80-89% THMFP, HAAFP, HANFP and HKFP, using 0.7-1.0 mg O3/mg DOC and 200 mg FeCl3/L). CP precursors which are formed during ozonation remain in the water after coagulation. The results obtained during this investigation show that the application of different oxidation and enhanced oxidation processes can reduce the contents of NOM and DBP precursors to some degree. The most effective process at removing both total organic matter and specific DBP precursors proved to be the Fenton process. With respect to enhanced oxidation processes based upon the use of ozone, by introducing catalysts or H2O2 as an oxidant in the ozonation process and by selecting the optimum pH for the process, the oxidizability of organic molecules can be improved. In addition, knowledge of the NOM oxidation mechanisms from different sources using ozone and / or hydroxyl radicals, as well as the mechanism of NOM removal by coagulation, can be used to select and optimize the most appropriate process in drinking water treatment, depending upon the quality of the raw water.

La désinfection de l’eau par le chlore est largement répandue dans le monde afin de limiter les risques d’infections. Cependant, le chlore peut réagir avec des composés organiques et inorganiques présents dans les eaux en formant des sous-produits de désinfection potentiellement toxiques pour la santé humaine. Parmi ceux-ci, les chloramines inorganiques et les trihalométhanes sont les composés majeurs formés dans les eaux, et leur quantification pose un défi majeur.Dans cette étude, deux systèmes d’analyse en flux ont été développés afin de faciliter la portabilité de ces systèmes et de minimiser le coût du développement. Le premier système vise à analyser les chloramines inorganiques dans les eaux, et repose sur l’utilisation d’un module de chromatographie multi-seringue (MSC), permettant la séparation des chloramines inorganiques, suivie d’une réaction de dérivation post colonne qui améliore la sensibilité de la quantification des chloramines inorganiques. Le deuxième système permet d’analyser les trihalométhanes, le protocole d’analyse automatisée repose sur une version améliorée et optimisée de la réaction de Fujiwara et une étape de préconcentration sur phase solide.Ces deux systèmes permettent ainsi de quantifier ces deux familles de sous-produits de désinfection d’une manière sensible, fiable, sélective et peu coûteuse en utilisant l’analyse en flux
Chlorination of water is widely used to reduce the risk of waterborne infections. However, chlorine can react with organic and inorganic species present in water leading to the formation of disinfection-by-products known to pose human health problems because of their toxicities, especially inorganic chloramines and trihalomethanes. Furthermore, the quantification of these compounds poses a major analytical challenge because, as far as we know, there is no sensitive method that can differentiate between inorganic chloramines, and there is no portable and inexpensive method for the analysis of trihalomethanes.Two flow analytical-based systems have been developed in this study to facilitate their portability and to minimize the cost of development. The first system aims to analyze inorganic chloramines in water, it is based on the use of a Multi-syringe chromatography (MSC) module, allowing inorganic chloramines separation, followed by a post-column derivatization step with a chromophoric reagent that enhances the sensitivity and the selectivity of detection. The second system has been developed for the analysis of trihalomethanes in water, it is based on the optimized Fujiwara’s reaction and on a solid phase preconcentration step.These two systems developed allows quantification of these two families of disinfection by-products in a sensitive, reliable, selective and cheap way by using flow analysis