Download or read book Investigation of Influence of the UV H2O2 Advanced Oxidation Process on Dissolved Organic Matter s Characteristics and Disinfection Byproduct Formation Potential Using UHRMS Methods written by Yingying Xiang and published by . This book was released on 2020 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of UV H2O2 Advanced Oxidation on Physical and Chemical Characteristics of Natural Organic Matter in Raw Drinking Water Sources written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focused on the physical and chemical transformations undergone by natural organic matter (NOM) in two natural waters (from British Columbia, Canada) during ultraviolet plus hydrogen peroxide (UV/H2O2) advanced oxidation treatment as a function of UV fluence (up to 2000 mJ cm−ƯƯƯƯƯ2Ư) and initial H2O2 concentration (up to 20 mg L−ƯƯƯƯƯƯ1Ư). Under these conditions NOM was not mineralized but the hydroxyl radical (" H) partially oxidized NOM leading to reductions in the chromophoric natural organic matter (CNOM) (i.e., NOM absorbing at 254 nm). NOM was degraded into more readily biodegradable compounds, such as aldehydes. An appreciable reduction in the very hydrophobic acid (VHA) fraction of NOM was observed. Considerable reductions in the formation potentials of trihalomethanes (THMs) or haloacetic acids (HAAs) were not observed. An increase in alkalinity slowed down the rate of degradation of CNOM during UV/H2O2. A dynamic kinetic model was developed to predict the degradation of CNOM. Model parameters were developed using isolated aquatic NOM from Suwannee River. For the two natural waters, the model adequately predicted the degradation of CNOM as a function of initial H2O2 concentration, irradiation time (i.e., UV fluence). Including the reduction in CNOM improved the modeling of H2O2 degradation, but H2O2 degradation was still slightly under predicted. For water that had undergone ultrafiltration (UF), NOM was readily mineralized during UV/H2O2 treatment due to the absence of high molecular size NOM. For water from which the VHA fraction of NOM was removed, UV/H2O2 treatment led to mineralisation of NOM suggesting that, when coupled with a pre-treatment capable of removing a large portion of the VHA fraction, UV/H2O2 can achieve reductions in TOC. Combining UV/H2O2 with downstream biological activated carbon (BAC) filtration led to reductions in NOM and formation potentials of THMs and HAAs. Formaldehyde and H2O2 were effectively removed by BAC. Devel.

Download or read book Disinfection By product Formation in Drinking Water Treated with Chlorine Following UV Photolysis UV H2O2 written by Remilekun Yetunde Adedapo and published by . This book was released on 2005 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: As far back as the early 1900's when it was discovered that water could be a mode of transmitting diseases, chlorine was used to disinfect water. In the 1970's, the formation of disinfection by-products (DBPs) from the reaction of chlorine with natural organic matter was discovered. Since then there have been various studies on alternative disinfectants that could inactivate microorganisms and at the same time form less or no disinfection by-products. More recently the ultraviolet (UV) irradiation has been used to both disinfect and remove organic contaminants in drinking water. Though the use of UV irradiation has been found to be very effective in the inactivation of microorganisms, it does not provide a residual effect to maintain the water's microbial quality in the distribution system. Due to this, a secondary disinfectant such as chlorine has to be used to achieve microbial stability, suggesting that the formation of chlorination disinfection by-products would still occur but perhaps in different quantities and with different chemical species. In this research, the use of factorial experiments and single factor experiments were used to determine the effects of pH, alkalinity and UV-fluence (dose) on the formation of three classes of disinfection by-products; haloacetic acids (HAAs), haloacetonitriles (HANs) and trihalomethanes (THMs). These disinfection by-products were measured in water samples following post-UV chlorination and the UV treatment was either UV photolysis or UV/H2O2. From the factorial experiment results, treatment of synthetic water with UV/H2O2, an advanced oxidation process (AOP), produced fewer post-UV chlorination disinfection by-products (PCDBPs) than UV photolysis. For chlorinated PCDBPs, the percentage difference between UV photolysis and UV/H2O2 was 55, 65 and 38% for total HAAs (HAA9), total HANs (THANs) and total THMs (TTHMs) respectively. The percentage difference between UV photolysis and UV/H2O2 for brominated PCDBPs was 41 and 42% for HAA9 and TTHMs respectively. Both the use of pH and alkalinity proved to be factors that were significant in affecting the yields of the PCDBPs studied. Increases in alkalinity were found to increase the formation of PCDBPs in the treatment of synthetic water with UV/H2O2. Alkalinity had the opposite effect for PCDBP formed under UV photolysis conditions. Increases in pH always decreased the formation of PCDBPs. In the single factor experiments, haloacetic acid concentrations were unaffected as alkalinity was increased but dichloroacetonitrile and chloroform increased in concentration under treatment conditions of UV photolysis followed by chlorination. The UV/H2O2 treatment resulted in a decrease in concentration of the PCDBPs. In the pH studies, water samples were subjected only to the UV/H2O2 treatments and a reduction in concentration of PCDBPs occurred between pH 7 and 9.

Download or read book CHARACTERIZATION AND TRANSFORMATION OF DISSOLVED ORGANIC MATTER DOM IN ENGINEERED ULTRAVIOLET UV PHOTOLYSIS AND UV BASED ADVANCED OXIDATION PROCESSES written by and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : Dissolved organic matter (DOM) is a complex mixture of heterogeneous surrogate organic compounds and includes natural organic matter (NOM), dissolved organic nitrogen (DON), dissolved organic phosphorous (DOP) and soluble microbial products (SMP). DOM plays a key role in moderating the aquatic biogeochemical cycle in freshwater ecosystems. Shedding light into the composition of freshwater DOM will aid in understanding the biogeochemical dynamics of freshwater ecosystems and consequently the role of DOM as a local climate regulator. An increase in de facto wastewater reuse has made the removal of DOM present in wastewater imperative, as DOM can be potentially toxic to human health. Additionally, wastewater DOM can reduce the efficiency of the treatment performances of advanced treatment techniques such as UV-advanced oxidation processes (UV-AOPs), as DOM can screen UV light and scavenge reactive radical species, thereby reducing the concentrations of reactive radical species that are available to destroy the target trace organic contaminants. Therefore, understanding the molecular composition of DOM present in wastewater as well as in the effluent to surface water is crucial, as this knowledge will aid in upgrading treatment performances and subsequently contribute towards the effective removal of target contaminants. In this regard, ultrahigh resolution mass spectrometry was used to evaluate the molecular composition of DOM present in wastewater as well as in the effluent to surface water. DOM composition is characterized in terms of H/C and O/C elemental ratios and double bond equivalents (DBEs). Effluent DOM was found to comprise of a higher number of unsaturated aromatic species relative to wastewater DOM. Species with nitrogen and sulfur heteroatoms are less common among effluent DOM relative to wastewater DOM. In order to better understand the interference of DOM in the treatment performances of individual UV-AOPs, the transformation of a standard DOM isolate, i.e. Suwannee River Fulvic Acid (SRFA) as well as municipal effluent wastewater DOM (EfOM) were investigated in UV/H2O2, UV/free chlorine and UV/persulfate AOPs using ultrahigh resolution mass spectrometry. The changes in the H/C and O/C elemental ratios, DBEs, and the low-molecular-weight transformation product concentrations reveal that different DOM and EfOM transformation patterns are induced by each UV-AOP. DOM and EfOM transformation routes induced by hydroxyl, chlorine and sulfate radicals were mechanistically elucidated by comparing the known reactivities of each active radical species with specific organic compounds. In the UV/H2O2 system, distinct transformation of aliphatic components of DOM and transformation of olefinic as well as aliphatic components of EfOM was observed. In the UV/free chlorine system, transformation of aliphatic as well as olefinic species of DOM and transformation of aromatic species of EfOM was observed. Transformation of aromatic and olefinic moieties of both DOM as well as EfOM was observed in the UV/persulfate system. Transformation products of DOM such as chlorinated compounds are of concern due to their adverse health impacts. However, only a small portion of these compounds have been well-characterized, thus necessitating the characterization of the unknown compounds. Plausible structural information about chlorinated compounds produced from UV/free chlorine triggered transformation of DOM is provided through the means of tandem mass spectrometry (MS/MS) with ultrahigh resolution mass analysis. The two compounds of interest were hypothesized to be composed of alcohol, carboxylic acid and aldehyde/ketone groups.

Download or read book Impact of UV and UV H2O2 AOP on EDC Activity in Water written by K. Linden and published by International Water Assn. This book was released on 2009-08 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this research was to assess, through u

Download or read book The Role of Advanced Oxidation Processes in Drinking Water Treatment written by Karine K. Philippe and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Removal of natural organic matter (NOM) is an ever growing challenge for water utilities as many surface waters used for drinking water in the UK exhibit increasing organics levels and it is well known that these organics can lead to problems such as water colouration, unpleasant odour and taste, bacterial growth and disinfection by-products (DBPs) formation. NOM is traditionally removed by coagulation, however in the case of hydrophilic organic matter rich waters the performances of these processes are not able to remove sufficient organic matter leading to potential failures of DBP regulations. Here two advanced oxidation processes (AOPs) UV/H2O2 and TiO2 photocatalytic oxidation were studied to investigate how they could be integrated in a drinking water flowsheet to meet this challenge. Substantial structural changes in the organic matter were observed: loss of aromaticity and double bonded character, shift towards lower molecular weight (MW) more hydrophilic compounds and formation of oxygenated by-products. Although hydrophobic rich waters seem more suitable to AOP treatment as preferential attack of high MW hydrophobic compounds was demonstrated, no correlation was found between physical properties of nine NOM surrogates and removal by UV/TiO2. Dark adsorption onto TiO2 was shown to remove preferentially high molecular weight hydrophobic anionic compound such as tannic acid. UV/H2O2 combined with coagulation did not show any significant benefits in NOM removal as UV/H2O2 appeared to target similar components as coagulation (high MW, hydrophobic and charged) and to form by-products recalcitrant to coagulation. The combination of both AOPs with fresh GAC showed moderate benefits inAbstractiitrihalomethane formation potential (THMFP) and non purgeable organic carbon (NPOC) removal highlighting the role of size and surface chemistry on adsorption onto GAC. Biodegradability of the water did not exhibit any significant change after both AOP treatments within the studied conditions possibly due to insufficient UV irradiation and presence of organics recalcitrant to biodegradation.

Download or read book A Comprehensive Assessment of the Effects of Ozone and UV Radiation on the Molecular Weight and Optical Properties of Natural Water and Wastewater Effluent Dissolved Organic Matter written by Allison Lee Paul and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The work presented concentrations on better understanding the physical and chemical properties of dissolved organic matter (DOM) in two distinctly different aquatic environments. More specifically, examining the degradation of DOM before and after oxidation treatments with ozone, ultra violet radiation (UVR), and combination of the two. DOM consists of low and high molecular weight species such as humic substances, hydrophilic acids, carboxylic acids, amino acids, carbohydrates, and hydrocarbons [1]. DOM is a component of the carbon cycle, serves as a nutrient source, impacts treatment processes, and plays an important role in the transportation of aquatic contaminates. However, the exact structure of DOM is still not fully understood because of its complex nature and origin. Chapter 1 is a brief introduction to DOM, including its role in natural and wastewater systems. This chapter also discusses the different types of oxidation processes and the interactions of oxidation with DOM. Chapter 2 is a brief introduction to the four analytical techniques that will be used in the analysis of natural water DOM (NDOM) and wastewater effluent DOM (efDOM). The four analytical techniques include: size exclusion chromatography (SEC), time-of-flight mass spectrometry (TOF MS), ultra-violet visible (UV-Vis) absorption spectroscopy, and excitation-emission matrix fluorescence spectroscopy (EEMS). Chapter 3 is understanding DOM in a natural water system. DOM is a key component in freshwater ecosystems, and strongly influences the optical, chemical, and biological environment. Therefore, it becomes important to understand the nature of DOM within this system. Many natural water systems are treated for drinking water purposes at water treatment facilities with the use of chlorine. The formation of hazardous disinfection by-products (DBPs) from the interaction of chlorine with DOM has lead to finding alternative methods for disinfection. The use of ozone, UVR, and the combination of these two will be examined on the degradation and removed of DOM in a natural water system. Chapter 4 is understanding the degradation DOM in a wastewater system after oxidation treatment. Natural water systems are known to be more of terrestrial origin, whereas wastewater is of microbally-derived origin. Therefore, it is important to understand the effects of oxidants in terrestrially-derived and microbally-derived systems. Chapter 5 aims at comparing NDOM and efDOM before and after advanced oxidation treatment (AOP). AOP is the combination of ozone and UVR. More specifically, this research examines two types of AOP treatments: (1) ozone and UVR from an artificial radiation source and (2) ozone and UVR from a natural radiation source. The will be determined which type of AOP is best suited for the degradation and removal of DOM in both systems and to determine if AOP has the same or different effect of DOM of two distinctly different systems. Four analytical techniques will be used in combination in order to better understand DOM characteristics for the studies performed in chapters 3, 4, and 5. Multimethod analysis will be used to develop a broad view of the DOM characteristics and will aid in revealing similarities and differences in NDOM and efDOM before and after advanced oxidation treatments. These four techniques include: (1) size exclusion chromatography (SEC) to qualitatively and quantitatively understand the molecular weight distribution of DOM, (2) time-of-flight mass spectrometry (TOF MS) to separate DOM based on the mass-to-charge ratio, (3) ultraviolet-visable (UV-Vis) absorption spectroscopy to understand the chromophoric character of DOM, and (4) exitation-emission matrix fluorescence spectroscopy to understand the fluorophoric origin of DOM. Chapter 6 is understanding the effects of microalgae bioremediation on wastewater DOM. Microalgae serve a dual role: they are environmentally-friendly alternatives to disinfection/oxidation of wastewater and produce biomass that can be used as biofuels and feeds. The most suitable conditions for maximum microalgae growth, and therefore maximum biomass and feed production is still largely unknown because microalgae growth depends on factors such as pH and temperature, concentration of essential nutrients, including nitrogen, phosphorus, and organic carbon, availability of light, oxygen, and carbon dioxide. Therefore, it is important to determine where in the treatment process would be suitable for maximum algae growth and greatest degradation of DOM. Two analytical techniques will be used collectively to better understand the interactions of microalgae and DOM-size exclusion chromatography and excitation emission matrix fluorescence spectroscopy.

Download or read book New Insights Into Disinfection Byproduct Formation and Control written by Ashley Dale Pifer and published by . This book was released on 2012 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods were developed for application of asymmetric flow field-flow fractionation (AF4) and fluorescence parallel factor (PARAFAC) analysis to raw and treated samples from drinking water sources to improve characterizations of dissolved organic matter (DOM) and discover DOM properties correlated to disinfection byproduct (DBP) formation potential (FP). Raw water samples were collected from a reservoir, adjusted to pH 6, 7, and 8 and subjected to (1) jar tests using aluminum sulfate (alum) and (2) treatment with magnetic ion exchange (MIEX®) resin. Both treatments were followed by DBPFP tests at pH 7. AF4 was used to size DOM in raw and alum treated samples at pH 6 and 8. AF4 fractograms showed that DOM removal was more effective at pH 6 than at pH 8, and preferential removal of larger-sized DOM occurred at pH 6 but not at pH 8. A fluorescence-PARAFAC model was constructed using excitation-emission matrices (EEMs) from all samples. A strong linear correlation (r 2 = 0.87) between chloroform FP and a humic-like PARAFAC component (C1) was developed. This correlation was a significant improvement over the correlation (r 2 = 0.03) between chloroform FP and specific ultraviolet absorbance at 254 nm (SUVA254), a DBPFP surrogate commonly used in drinking water treatment plants to optimize DOM removal processes. This indicated that chloroform FP-C1 correlations were not treatment-specific. Alum coagulation at pH 6, 7, and 8 and DBPFP tests at pH 7 were performed on a set of raw waters from eleven drinking water treatment plants from across the United States. AF4 was used to size DOM before and after alum coagulation, and showed similar results to the earlier study, i.e., increased removal at pH 6 compared to pH 8. A fluorescence-PARAFAC model was constructed and total trihalomethane (TTHM) FP was strongly correlated (r 2 = 0.91) to C1 for eight water sources. TTHMFP-SUVA254 correlations for ten locations were weak (r 2 = 0.15), which indicated that C1 was an improved DBPFP surrogate relative to SUVA254 and could be used as a surrogate to select and optimize DBP precursor removal processes.

Download or read book Effects of UV H2O2 Process on Characteristics of Disinfection By products DBPs Formation from Nitrogenous Organic Precursors written by 梁幃杰 and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamics in the Reactivity and Photochemical Production of Hydroxyl Radical in Treated Wastewater Effluent and Aquatic Dissolved Organic Matter written by Molly C. Semones and published by . This book was released on 2017 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: The hydroxyl radical (HO•) is a photochemically generated species that is important in the attenuation of organic contaminants in sunlit natural surface waters and in advanced oxidation processes (AOPs) used to treat drinking and wastewater. The steady state concentration of HO•, ([HO•]ss), in photochemical systems is typically measured indirectly using probe compounds. In this work, we investigate the use of caffeine as a photochemical probe for the detection of HO• in the presence of dissolved organic matter (DOM) solutions derived from allochthonous and autochthonous precursors using both the first order and initial rates approach to kinetic analysis to determine [HO•]ss in aqueous solution. Values for [HO•]ss are found to agree within a factor of two of values measured using terepthalic acid (TPA), a well-established probe for the detection of HO•, in the identical DOM solutions. Additionally, we find that caffeine is more selective for HO• than previously believed since it does not appear to undergo reaction with long-lived reactive transients as was formerly presumed. The presence of nitrate in wastewater effluent could play an important role in the formation of HO•, and therefore also in the fate of contaminants in sunlit receiving waters. We investigate the interplay between HO• formation derived from both effluent dissolved organic matter (EfOM) and nitrate (NO3-). The assumption of little to no interaction between NO3- and EfOM during HO• production (RHO•), needed to determine the contribution of DOM to hydroxyl radical formation in waters containing NO3- without extracting EfOM from the wastewater, is invalid. We based our findings on measurements of RHO• and [HO•]ss using benzene and caffeine as HO• probes in both whole wastewater effluent and solutions of EfOM isolated by solid phase extraction from the same effluent sample. The RHO• value measured for the isolate in the absence of NO3- (0.074 ± 0.009 (SE) nM s-1) is 1.5 fold higher than that found for bulk, non-isolated EfOM (0.049 ± 0.026 (SE) nM s-1), which was calculated by subtracting the estimated contribution of NO3- to overall HO• production from the RHO• obtained for the Southerly whole wastewater. This difference calculated this way is not significantly different (a=0.05, p=0.39). We find that we are able to reproduce the RHO• found with benzene for Southerly wastewater effluent (0.199 ± 0.022 nM s-1) using a NO3-ROH• curve generated in a Southerly isolate solution (0.178 ± 0.011 nM s-1). Similarly, [HO•]ss values measured in Southerly whole wastewater effluent using caffeine as a probe compound (1.32 ± 0.096 fM) were comparable to measurements made in Southerly EfOM (1.50 ± 0.091 fM). We revise the ratio at which NO3- and DOM contribute equally in solution from the value reported by Vione et al. (2006) of 3.3 x 10-5 [(mol NO3-) (mg-C)-1]) upwards to 8.1 ± 1.5 x 10-5 [(mol NO3-) (mg-C)-1] based on the average of the ratios determined for the three DOM isolates used in this study. Values for [HO•]ss in IHSS isolate solutions and whole wastewater effluent determined by benzene and caffeine are in good agreement, which supports the use of caffeine as a credible HO• probe compound, subject to caveats detailed within this work, in both isolate solutions and whole water containing NO3-. Organic UV-filters are key ingredients found in sunscreens, cosmetics and plastic goods. Concerns have been raised about potential ecological and human health effects of certain organic UV filters that are currently FDA approved for use in the United States. Here, we investigate the photochemical fate of two of these compounds, oxybenzone and sulisobenzone. Both oxybenzone and sulisobenzone have previously been detected in surface waters, seawater, and treated wastewater effluent. Enhanced photodegradation of oxybenzone and sulisobenzone was observed under simulated solar irradiation in solutions of International Humic Substance Society standards (Pony Lake fulvic acid and Suwannee River Natural Organic Matter), filtered wastewater effluent (Southerly Wastewater Treatment Plant in Lockbourne, OH), and Scioto River water (Columbus, OH). Quenching experiments with isopropanol revealed that the main pathway for degradation appears to be reaction with the hydroxyl radical (HO•). Observed degradation rates were 2-3 times slower than estimates calculated using literature reported second-order rate constants and measured hydroxyl radical steady-state concentrations for SRNOM, PLFA and Scioto waters. The Southerly sample, however, exhibited nearly identical expected and observed rate constants, which we take to indicate the presence of unidentified reactive species that can react with oxybenzone and sulisobenzone. Values obtained in this work were used to calculate second-order rate constants for oxybenzone and sulisobenzone with the hydroxyl radical, as well as to estimate environmental half-lives for these compounds. Near surface 24-hour averaged half-lives of 3.0 and 4.0 days were calculated for oxybenzone and sulisobenzone,respectively. When extrapolated to an environmentally representative water column, these same 24-hour averaged half-lives increased to 2.4 and 3.5 years, respectively.

Download or read book Effects of Uv h2o2 Oxidation Process on Disinfection By products Formation for Algae and Activated Sludge written by 歐泰佑 and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effects of Dissolved Organic Matter on Pollutant Removal and Formation in Aquatic Environment written by Meng-Horng Hsu and published by . This book was released on 2012 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrophobic organic pollutants (HOPs), such as polyaromatic hydrocarbons primarily from automobile exhausts and dissolved organic matter (DOM) are ubiquitous in the aquatic environment. The association between DOM and HOPs as a bound interaction of DOM-HOPs minimizes the bioavailability of free HOPs and their potential health effects. In addition, DOM is also the precursor of disinfection by-products involving the disinfection treatment processes. It is very important to understand the relationship between free and bound HOPs, disinfection by-products, and DOM in drinking water treatment, stormwater runoff and dry weather flow of aquatic environment. This thesis will explore the binding phenomenon between HOPs and DOM in raw and treated water from water treatment plants, after powdered activated carbon treatment, and in stormwater runoff and dry weather flow. This thesis also introduced the analytical methodologies for characterizing DOM and the hazardous potential of HOPs and thus understanding their relationship. DOM characteristics were measured for: 1) total concentration of organic carbon by dissolved organic carbon (DOC), 2) aromaticity by UV absorbance and specific UV absorbance (SUVA), and 3) size distribution by ultrafiltration (UF), 4) polarity by polarity rapid assessment method (PRAM), 5) UV and fluorescent chemical components by UV spectrometer and fluorescence excitation-emission matrix (EEM) and fluorescence regional integration (FRI). Hazardous potential of HOPs was measured by fluorescence quenching determined partition coefficient KDOM. Studies have been completed and showed that monitoring both the free and bound forms of HOPs as well as disinfection by-products (such as, trihalomethanes) and their relationship to DOM during drinking water treatment processes is necessary to better understand drinking water quality and give more effective suggestions to optimize treatment processes. In addition, this work showed the relationship between DOM and HOPs in equilibrium with DOM-HOPs needs definition on a seasonal basis to understand the bioavailability of HOPs in dry weather flow and stormwater runoff events. The determination of free and total HOPs has not been considered in the California "State Implementation Plan" for water quality-based effluent limits of HOPs. A method using a standard probe- perylene has been developed to be able to evaluate these situations on a site specific basis since DOM is site specific. Key findings of this study were: 1) DOM characteristics are different from site to site and affect pollutants removal and formation. 2) Bulk SUVA shows a positive correlation with Log KDOM (R2=74%). Thus, DOM with more aromatic structure can result in higher binding between HOPs and DOM. 3) DOM with higher concentration, aromaticity, and molecular weight can have more ability to form THMs. 4) Under the conditions studied, PAC (20 mg/L) is an effective method to control both THMs and the hazard potential of HOPs. 5) DOM in urban runoff with higher molecular weight and aromaticity can associate with more HOPs. As a result, the distribution of HOPs affected by DOM in urban runoff needs definition on a seasonal basis and runoff types.

Download or read book The UV H2O2 Advanced Oxidation Process in UV Disinfection Units written by Alexandros Machairas and published by . This book was released on 2004 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, the issue of how to remove phosphate esters from drinking water is examined. From the various treatment processes available, the oxidation of phosphate esters through hydroxyl radical generated by the UV/H202 process applied at a UV disinfection unit was selected for evaluation. The second-order rate constants of the reactions of two phosphate esters, Tri(2-butoxyethyl) phosphate (TBEP) and Tri-2-chloroethyl phosphate (TCEP), with hydroxyl radical were estimated from our experimental data to be 2.1000 M-1s-1 and 2 109 M-is-1 respectively A comprehensive kinetic model of the oxidation process was derived. Finally computer simulations were used to exhibit the potential of this treatment process and to examine the effects of pH, total carbonate species concentration, initial hydrogen peroxide dose, and light intensity on its efficiency. The results are not very encouraging when a UV unit designed for disinfection is used. For typical values of pH and total carbonate species (pH=8 and CT=5' 10-4 M) the 1 s order rate coefficients for removal of the phosphate esters are 6.3 10-4 (s-1) for TBEP and 6.3 10-5 (s-1) for TCEP. If higher light intensity is applied in the reactor (50 times higher), and initial hydrogen peroxide dose of 10-3 M and CT remains 5 10-4 M, the 1st order reaction rate coefficients become 2.9 10-2 (s-1) and 2.9-10-3 (s-1) for TBEP and TCEP respectively.

Download or read book Effects of UV HO Advanced Oxidation on Physical and Chemical Characteristics of Natural Organic Matter in Raw Drinking Water Sources written by Siva Rajan Sarathy and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fluorescence and UV Methods for Predicting Dissolved Organic Carbon and Disinfection By product Formation in Drinking Water written by Andrew Theodoros Skeriotis and published by . This book was released on 2011 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolved organic carbon (DOC) poses many challenges for drinking water treatment plants (WTP) as its reaction with chlorine produces disinfection by-products (DBP) which are undesirable because if their harmful effect on humans and is also regulated by the United States Environmental Protection Agency (U.S. EPA). Parallel factor (PARAFAC) analysis, fluorescence regional integration (FRI), excitation-emission matrices (EEM) maximum peaks and ultra-violet absorbance (UVA) are all optical analysis methods used to characterize DOC and its contribution to disinfection byproduct (DBP) formation. Multifactor linear regression models were developed from these optical analysis methods to predict DOC concentrations and DBP formation from raw water and coagulated water collected from a WTP. This comprehensive study utilized 492 total samples collected from January 2010 to July 2011 that were used in the DOC analysis while 88 total samples (September 2010 to July 2011) were used for the DBP analysis. The models were evaluated statistically to determine which of the optical analysis techniques performed the best in predicting DOC concentration and DBP formation. PARAFAC analysis had the highest linear correlations of all the models tested and had statistically significant components characterizing the nature of DOC and the precursors to DBP formation. The speed, sensitivity and low cost of PARAFAC analysis shows great promise for incorporation of PARAFAC components into a WTP operation helping them make more informed and science-based decisions to treatment train processes.

Download or read book Use of UV and Fluorescence Spectra As Surrogate Measures for Contaminant Oxidation and Disinfection in the Ozone H2O2 Advanced Oxidation Process written by Shane A. Snyder and published by . This book was released on 2013-10 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Oxidation Processes written by Rupa Lamsal and published by . This book was released on 2012 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT Cont'd. : Bench-scale experiments conducted to evaluate the performance of ozone (O3), ultraviolet (UV), hydrogen peroxide plus ozone (H2O2/O3), H2O2 plus UV (H2O2/UV) and O3 plus UV (O3/UV) for reducing NOM and DBP precursors suggested that the O3/UV AOP offers the optimum reduction of NOM. Integrating AOP pretreatments with NF membrane resulted in an improved permeate flux but not permeate quality of the NF membrane.