Dissertations / Theses on the topic 'Disinfection by-products'
To see the other types of publications on this topic, follow the link: Disinfection by-products.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Disinfection by-products.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
梁啟承 and Kai-shing Alex Leung. "Control of disinfection by-products." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41549429.
Full text
2
Leung, Kai-shing Alex. "Control of disinfection by-products." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41549429.
Full text
3
McAuley, Kimberley. "Disinfection by-products and public health concerns." University of Western Australia. School of Population Health, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0070.
Full textAbstract:
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.
4
Broers, Teresa. "Abruptio placentae and chlorination disinfection by-products." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ63274.pdf.
Full text
5
Atılgan, Mehmet Reşat Ünlütürk Sevcan. "Disinfection of Liqued Egg Products By Using Uv Light /." [S.l. : s.n.], 2007. http://library.iyte.edu.tr/tezler/master/biyoteknoloji/T000656.pdf.
Full text
6
Iszatt, Nina. "Exposure to chlorination disinfection by-products and adverse reproductive outcomes." Thesis, Imperial College London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538676.
Full text
7
McAskill, John Blake. "Novel pathways for the formation of iodinated disinfection by-products." Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/547.
Full textAbstract:
The objective of this project was to investigate a novel pathway for the formation of the iodinated disinfection by-products iodoform and iodoacetic acid. The NOM/metal oxide/I- system was verified to form both iodinated disinfection by-products in relevant environmental conditions near neutral pH. Research was conducted further by using authentic pipe deposit as the metal oxide. The two iodo-DBPs were detected in the NOM/pipe deposit/I- system, as well as in the absence of NOM. The hypothesis for this research was that the two iodinated disinfection by-products would form in drinking water distribution systems by a reaction between natural organic matter, authentic pipe deposit, and iodide.
8
Sexton, Diane Lynne. "Analysis of disinfection by products in drinking water by solid phase extraction." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09122009-040321/.
Full text
9
Ates, Nuray. "Disinfection By-products Formation In Low - Bromide And Low - Suva Waters." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609489/index.pdf.
Full textAbstract:
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 Alibeyköy 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%.
10
Martin, Kelly M. "Are disinfection by-products in tapwater associated with intrauterine growth retardation?" Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31269.
Full textAbstract:
Introduction. Chlorination of surface water for human consumption results in a number of potentially toxic by-products. Recent investigation of the effects of these by-products on reproductive outcomes has demonstrated small increases in the risk of both intrauterine growth retardation and low birthweight with increasing exposure.Objective. The primary objective of this study was to examine the relationship between one group of disinfection by-products, trihalomethanes, and intrauterine growth retardation. The secondary objective was to compare the relationship found with the commonly used estimate of exposure, THM concentration, to that found with aggregate exposure measures.
Methods. A case-control study was carried out with 200 cases and 200 matched controls. The risk of THM exposure was estimated using conditional logistic regression, controlling for the confounding effect of maternal smoking, prepregnancy weight and education.
Results. A small, but imprecise, increase in the risk of IUGR was found with increasing levels of the brominated THMs, particularly bromoform. A decrease in the odds ratio was observed with increasing exposure information in the aggregate measures.
Conclusions. The results of this study support previous studies demonstrating a relationship between THMs and intrauterine growth retardation, particularly the brominated THMs. However, the small sample size does not allow any firm conclusions to be drawn about this relationship.
11
Sfynia, Chrysoula. "Minimisation of regulated and unregulated disinfection by-products in drinking water." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/58879.
Full textAbstract:
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.
12
Mohsen, Behbahani. "Investigation on disinfection by products (DBPs) degradation in water distribution systems." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1533308679365808.
Full text
13
Ebbett, Virginia Rose. "The Chlorination of Triclosan: A Kinetic Study." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/43524.
Full textAbstract:
Triclosan, 5-chloro-2-(2,4 dichlorophenoxy)phenol, is an anti-microbial additive in a plethora of Pharmaceutical and Personal Care Products (PPCPs) including, toothpastes, hand creams and soaps, and acne creams. Because many triclosan containing products are topical solutions that are readily washed down the drain, significant quantities of triclosan can be introduced to wastewater treatment systems and eventually, to surface waters. Consequently, triclosan has become a contaminant of concern. The reactions between triclosan and free chlorine have been examined previously; however, no kinetic data for these reactions have been reported for conditions typical of drinking water treatment. This investigation focused specifically on the kinetics of the triclosan and free available chlorine (FAC) reactions under drinking water treatment conditions. Triclosan readily reacted with free chlorine via a second-order reaction (first order with respect to each species). No significant temperature dependency was observed from 8 to 25 °C. The reaction stoichiometry was determined to be 1:1 (triclosan oxidized per free chlorine reduced and did not vary over the pH range examined (pH 4-12). However, the reaction rate coefficients exhibited a significant pH dependency. A model that incorporates the rate coefficients for the reactions between HOCl and both neutral and anionic forms of triclosan was generated to fit the experimental data. The anionic free chlorine species hypochlorite (OCl-) was determined to play an insignificant role in the overall rate of reaction, and therefore, only the reactions involving HOCl were incorporated into the model. Additionally, a hypothesized reaction mechanism was tentatively shown to fit the collected data and its strong pH dependency.Master of Science
14
Ranmuthugala, Geethanjali Piyawadani, and Geetha Ranmuthugala@anu edu au. "Disinfection by-products in drinking water and genotoxic changes in urinary bladder epithelial cells." The Australian National University. National Centre for Epidemiology and Population Health, 2001. http://thesis.anu.edu.au./public/adt-ANU20011207.110344.
Full textAbstract:
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.
15
Mirlohi, Susan. "Chemical Identification and Flavor Profile Analysis of Iodinated Phenols Produced From Disinfection of Spacecraft Drinking Water." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/30997.
Full textAbstract:
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
16
Do, Minh T. "Chlorination disinfection by-products in drinking water and risk of pancreatic cancer." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6258.
Full textAbstract:
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.
17
McDonnell, Bryant E. "Controlling disinfection by-products within a distribution system by implementing bubble aeration within storage tanks." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342728645.
Full text
18
Greyshock, Aimee E. "Evaluation of Triclosan Reactivity in Monochloraminated Waters." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/36295.
Full textAbstract:
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
19
Ranmuthugala, Geethanjali Piyawadani. "Disinfection by-products in drinking water and genotoxic changes in urinary bladder epithelial cells." View thesis entry in Australian Digital Theses Program, 2001. http://thesis.anu.edu.au/public/adt-ANU20011207.110344/index.html.
Full text
20
Grellier, James. "Environmental health impact assessment of exposure to disinfection by-products in drinking water." Thesis, Imperial College London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542936.
Full text
21
Lui, Yuen Shan. "Formation of disinfection by-products and mutagenicity upon chlorination of algal-derived organic materials." HKBU Institutional Repository, 2010. http://repository.hkbu.edu.hk/etd_ra/1181.
Full text
22
Crafton, Elizabeth Ann. "Formation Of Iodinated Disinfection By-Products From Iodinated X-ray Contrast Media, Iopamidol, In The Presence Of Nom And Chlorinated Oxidants." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1418148916.
Full text
23
Xie, Mingyu. "Model predictive control of water quality in drinking water distribution systems considering disinfection by-products." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7207/.
Full textAbstract:
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.
24
Carter, Rhys Aaron Ainsley. "Understanding the Chemistry of Disinfection By-Products in Swimming Pools to Minimise Chemical Health Risks." Thesis, Curtin University, 2019. http://hdl.handle.net/20.500.11937/76068.
Full textAbstract:
Swimming pools contain organic compounds originating from both filling water and bather load. These organic compounds react with added disinfectants to form unwanted disinfection by-products in the pools. This Thesis presents an improved understanding of the occurrence and formation of disinfection by-products in pools and their potential chemical health risks. It provides significant knowledge for pool operators and the leisure industry to drive improvements in the chemical water quality of pools in the future.
25
Liu, Jinlin, and 刘金林. "Wastewater organic as the precursors of disinfection byproducts in drinking water: characterization,biotransformation and treatment." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46289562.
Full text
26
Wang, Zhikang. "Influence of Biofilm on Disinfection Byproducts Formation and Decay in a Simulated Water Distribution System." University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1372343403.
Full text
27
Bougeard, Cynthia. "Haloacetic acids and other disinfection by-products in UK treated waters : occurence, formation and precursor investigation." Thesis, Cranfield University, 2009. http://dspace.lib.cranfield.ac.uk/handle/1826/4431.
Full textAbstract:
Disinfection by-products (DBPs) in drinking water are formed when natural organic matter (NOM) that remains after initial treatment reacts with disinfectants, such as chlorine or chloramines. DBPs, which are of health concern, can take the form of trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs), haloacetaldehydes (HAs), halonitromethanes (HNMs) and a host of other halogenated DBPs. So far, regulations in the United Kingdom (UK) only encompass the group of THMs allowing a maximum level of 100 µg/L. HAAs, the second most prevalent class of DBPs, are currently under consideration by the European Union to be regulated at 80 µg/L. Reliable and reproducible quantification methods are required for DBP detection. To address this need, the presented work includes a comparative study between analytical devices, which concludes that GC/ECD is the only approach with suitable detection limits. This work reports an investigation of the DBP formation potential (FP) of waters from 11 water treatment works (WTWs) at different locations in the UK. Several of these waters have shown to form significant levels of HAAs and THMs. Furthermore, other DBPs, such as iodo-THMs (i-THMs), HANs, HKs, HAs and HNMs were detected. It has also been confirmed that improving the control of these DBPs can be achieved by using monochloramine instead of free chlorine. A statistical analysis revealed that THMs correlated well with the HAAs, and as a result the regulatory limit of 100 µg/L for the THM4 would fail a regulation of 80 µg/L for the nine HAAs. A number of parameters have been identified, which have particular relevance when considering the formation of HAAs and THMs in treated waters. Threshold bromide level was determined beyond which speciation of DBPs shift toward brominated species. The pH, which significantly affected THMs, was less strongly linked to the HAAs. The temperature had a consistent impact with a decreasing DBP formation at lower temperatures. Increasing the contact time with the disinfectant resulted in parallel first order reaction kinetics of the HAAs and THMs. Finally, the precursors involved in the formation of DBPs were found to be specific to water sources.
28
Lutz, Theresa Marie. "A Study of the Precursors for Disinfection By-Products on the CAP Avra Valley Recharge Project." Thesis, The University of Arizona, 2000. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0114_sip1_w.pdf&type=application/pdf.
Full text
29
Sketchell, J. "The removal of dissolved organic carbon and disinfection by-products from prairie surface drinking water supplies." Thesis, Edinburgh Napier University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295376.
Full text
30
Mezgebe, Bineyam. "Innovative Biological Destruction of Hazardous Chlorinated and Brominated Volatile Disinfection By-products using Bio Trickling Filters." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1515505465180454.
Full text
31
Nottle, Caroline E. "Advanced water treatment technologies to minimise the formation of emerging disinfection by-products in potable water." Thesis, Curtin University, 2013. http://hdl.handle.net/20.500.11937/2452.
Full textAbstract:
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.
32
Park, Sang Hyuck. "Effect of amine-based water treatment polymers on the formation of N-nitrosodimethylamine (NDMA) disinfection by-product." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22549.
Full textAbstract:
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.
33
Hargette, Paul Hudson. "Removal of dissolved organic carbon and organic halide precursors by enhanced coagulation." Thesis, This resource online, 1997. http://scholar.lib.vt.edu/theses/available/etd-08252008-162839/.
Full text
34
Hong, Huachang. "Characteristics of natural organic matter in Hong Kong's source drinking water and its association with the formation of disinfection by-products." HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/894.
Full text
35
Dodd, Jennifer Peters. "Chemical Identification and Organoleptic Evaluation of Iodine and Iodinated Disinfection By-Products Associated with Treated Spacecraft Drinking Water." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36642.
Full textAbstract:
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
36
Wang, Yuxin. "Source Water Quality Assessment and Source Water Characterization for Drinking Water Protection." Research Showcase @ CMU, 2014. http://repository.cmu.edu/dissertations/416.
Full textAbstract:
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.
37
Metch, Jacob W. "Effects of Microbial Community Stress Response and Emerging Contaminants on Wastewater Treatment Plants." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/85257.
Full textAbstract:
As the population in water stressed areas increases, it is critical that wastewater treatment plants (WWTPs) continue to replenish depleted water supplies, and serve as an alternative water source. WWTPs depend on microorganisms in activated sludge to remove pollutants from wastewater and therefore an understanding of how these microorganisms are affected by various conditions and pollutants is needed. Also, as consumer products and industrial processes evolve, so do the pollutants they discharge to wastewater. In order to keep pace with these changes, understanding the effects of emerging contaminants to WWTP processes is essential. The research herein assesses microbial community dynamics of the response of nitrifying microorganisms in activated sludge to variation in ammonia concentration and evaluates the impact of engineered nanoparticles on activated sludge microbial communities and other emerging pollutants, such as antibiotic resistance genes and disinfection by-products.
In order to assess microbial community dynamics of the response of nitrifying microorganisms to removal of ammonia in the feed, nitrifying activated sludge reactors were operated at various relevant temperatures and the nitrifying microbial community was characterized using activity assays and bio-molecular techniques. We found that Nitrospira spp. were the dominant nitrifying microorganisms, exhibiting stable relative abundance across multiple trials and over a range of temperatures. These results indicate the possibility of comammox bacteria in the system and highlight the complexity of nitrifying microbial communities in activated sludge relative to past understanding.
Both microbial and chemical impacts of engineered nanoparticles on WWTP processes were also investigated. Metagenomic analysis of DNA extracted from activated sludge sequencing batch reactors dosed with gold nanoparticles with varied surface coating and morphology indicated that nanoparticle morphology impacted the microbial community and antibiotic resistance gene content more than surface coating. However, nanoparticle fate was controlled by surface coating more than morphology. Disinfection by-product formation in the presence of nanoparticles during WWTP disinfection was assessed using silver, titanium dioxide, ceria, and zero valent iron nanoparticles. Silver nanoparticles were found to enhance trihalomethane formation, which was attributed to the citrate coating of the nanoparticles. These studies both raise concern over the relationship between engineered nanoparticles and other emerging concerns in WWTPs, and take a step towards informing nanoparticle design in a manner that limits their associated environmental impact.Ph. D.
38
Li, Chi-Wang. "Characterizing the properties and reactions of natural organic matter by UV spectroscopy : adsorption of NOM and formation of disinfection by-products /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/10150.
Full text
39
Hoffman, Caroline Smith Savitz David A. "Exposure to drinking water disinfection by-products and pregnancy health impacts on fetal growth and duration of gestation /." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1229.
Full textAbstract:
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.
40
Bush, Kelly Lynn. "Assesment of drinking water quality using disinfection by-products in a distribution system following a treatment technology upgrade." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2447.
Full textAbstract:
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.
41
Whitaker, Heather Joy. "Exposure assessment of chlorination disinfection by-products for use in epidemiological studies of water quality and birth outcomes." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399986.
Full text
42
Wang, Fang. "Chlorine Contribution to Quantitative Structure and Activity Relationship Models of Disinfection By-Products' Quantum Chemical Descriptors and Toxicities." FIU Digital Commons, 2009. http://digitalcommons.fiu.edu/etd/174.
Full textAbstract:
Quantitative Structure-Activity Relationship (QSAR) has been applied extensively in predicting toxicity of Disinfection By-Products (DBPs) in drinking water. Among many toxicological properties, acute and chronic toxicities of DBPs have been widely used in health risk assessment of DBPs. These toxicities are correlated with molecular properties, which are usually correlated with molecular descriptors. The primary goals of this thesis are: 1) to investigate the effects of molecular descriptors (e.g., chlorine number) on molecular properties such as energy of the lowest unoccupied molecular orbital (ELUMO) via QSAR modelling and analysis; 2) to validate the models by using internal and external cross-validation techniques; 3) to quantify the model uncertainties through Taylor and Monte Carlo Simulation. One of the very important ways to predict molecular properties such as ELUMO is using QSAR analysis. In this study, number of chlorine (NCl) and number of carbon (NC) as well as energy of the highest occupied molecular orbital (EHOMO) are used as molecular descriptors. There are typically three approaches used in QSAR model development: 1) Linear or Multi-linear Regression (MLR); 2) Partial Least Squares (PLS); and 3) Principle Component Regression (PCR). In QSAR analysis, a very critical step is model validation after QSAR models are established and before applying them to toxicity prediction. The DBPs to be studied include five chemical classes: chlorinated alkanes, alkenes, and aromatics. In addition, validated QSARs are developed to describe the toxicity of selected groups (i.e., chloro-alkane and aromatic compounds with a nitro- or cyano group) of DBP chemicals to three types of organisms (e.g., Fish, T. pyriformis, and P.pyosphoreum) based on experimental toxicity data from the literature. The results show that: 1) QSAR models to predict molecular property built by MLR, PLS or PCR can be used either to select valid data points or to eliminate outliers; 2) The Leave-One-Out Cross-Validation procedure by itself is not enough to give a reliable representation of the predictive ability of the QSAR models, however, Leave-Many-Out/K-fold cross-validation and external validation can be applied together to achieve more reliable results; 3) ELUMO are shown to correlate highly with the NCl for several classes of DBPs; and 4) According to uncertainty analysis using Taylor method, the uncertainty of QSAR models is contributed mostly from NCl for all DBP classes.
43
Afreh, Isaac K. "A Non-Biological Inhibition Based Sensing Technique (NIBS) for the Detection of Halogenated Disinfection By-Products in Water." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1366068222.
Full text
44
Kassouf, Helene. "Formation of Trihalomethanes (THMs) as Disinfection by-Products (DBPs) when Treated Municipal Wastewater is Disinfected with Sodium Hypochlorite." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6522.
Full textAbstract:
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
45
Cheung, Lok Man. "Investigation of virus inactivation and by-products formation under sequential disinfection using UV irradiation and free chlorine/monochloramine /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202004%20CHEUNG.
Full textAbstract:
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.
46
Farren, Elizabeth Anne. "Reducing trihalomethane concentrations by using chloramines as a disinfectant." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0429103-095058.
Full text
47
Chen, Rena Zhanglei. "Development, validation and uncertainty analysis of quantitative structure and activity relationship models for Log P of disinfection by-products." FIU Digital Commons, 2009. http://digitalcommons.fiu.edu/etd/2145.
Full textAbstract:
Hydrophobicity as measured by Log P is an important molecular property related to toxicity and carcinogenicity. With increasing public health concerns for the effects of Disinfection By-Products (DBPs), there are considerable benefits in developing Quantitative Structure and Activity Relationship (QSAR) models capable of accurately predicting Log P. In this research, Log P values of 173 DBP compounds in 6 functional classes were used to develop QSAR models, by applying 3 molecular descriptors, namely, Energy of the Lowest Unoccupied Molecular Orbital ( ELUMO), Number of Chlorine (NCl) and Number of Carbon (NC) by Multiple Linear Regression (MLR) analysis. The QSAR models developed were validated based on the Organization for Economic Co-operation and Development (OECD) principles. The model Applicability Domain (AD) and mechanistic interpretation were explored. Considering the very complex nature of DBPs, the established QSAR models performed very well with respect to goodness-of-fit, robustness and predictability. The predicted values of Log P of DBPs by the QSAR models were found to be significant with a correlation coefficient R2 from 81% to 98%. The Leverage Approach by Williams Plot was applied to detect and remove outliers, consequently increasing R2 by approximately 2% to 13% for different DBP classes.
The developed QSAR models were statistically validated for their predictive power by the Leave-One-Out (LOO) and Leave-Many-Out (LMO) cross validation methods. Finally, Monte Carlo simulation was used to assess the variations and inherent uncertainties in the QSAR models of Log P and determine the most influential parameters in connection with Log P prediction. The developed QSAR models in this dissertation will have a broad applicability domain because the research data set covered six out of eight common DBP classes, including halogenated alkane, halogenated alkene, halogenated aromatic, halogenated aldehyde, halogenated ketone, and halogenated carboxylic acid, which have been brought to the attention of regulatory agencies in recent years. Furthermore, the QSAR models are suitable to be used for prediction of similar DBP compounds within the same applicability domain. The selection and integration of various methodologies developed in this research may also benefit future research in similar fields.
48
Peng, Di [Verfasser], and H. [Akademischer Betreuer] Horn. "Disinfection by-products and the application potential of nanofiltration in swimming pool water treatment / Di Peng ; Betreuer: H. Horn." Karlsruhe : KIT-Bibliothek, 2016. http://d-nb.info/1124068716/34.
Full text
49
Karnik, Bhavana Sushilkumar. "The use of ozonation and catalytic ozonation combined with ultrafiltration for the control of natural organic matter (NOM) and disinfection by-products (DBPS) in drinking water." Diss., Connect to online resource - MSU authorized users, 2006.
Find full textAbstract:
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.
50
Boyalla, Rajya Lakshmi. "Formation and modeling of disinfection by-products in Newfoundland communities /." 2004.
Find full text