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James R Bolton - One of the best experts on this subject based on the ideXlab platform.
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pilot scale uv h2o2 Advanced Oxidation Process for municipal reuse water assessing micropollutant degradation and estrogenic impacts on goldfish carassius auratus l
Water Research, 2016Co-Authors: Zengquan Shu, James R Bolton, Miodrag Belosevic, Arvinder Singh, Nikolaus Klamerth, Kerry N Mcphedran, Mohamed Gamal EldinAbstract:Low concentrations (ng/L-μg/L) of emerging micropollutant contaminants in municipal wastewater treatment plant effluents affect the possibility to reuse these waters. Many of those micropollutants elicit endocrine disrupting effects in aquatic organisms resulting in an alteration of the endocrine system. A potential candidate for tertiary municipal wastewater treatment of these micropollutants is ultraviolet (UV)/hydrogen peroxide (H2O2) as an Advanced Oxidation Process (AOP) which was currently applied to treat the secondary effluent of the Gold Bar Wastewater Treatment Plant (GBWWTP) in Edmonton, AB, Canada. A new approach is presented to predict the fluence-based degradation rate constants (kf') of environmentally occurring micropollutants including carbamazepine [(0.87-1.39) × 10(-3) cm(2)/mJ] and 2,4-Dichlorophenoxyacetic acid (2,4-D) [(0.60-0.91) × 10(-3) cm(2)/mJ for 2,4-D] in a medium pressure (MP) UV/H2O2 system based on a previous bench-scale investigation. Rather than using removal rates, this approach can be used to estimate the performance of the MP UV/H2O2 Process for degrading trace contaminants of concern found in municipal wastewater. In addition to the ability to track contaminant removal/degradation, evaluation of the MP UV/H2O2 Process was also accomplished by identifying critical ecotoxicological endpoints (i.e., estrogenicity) of the treated wastewater. Using quantitative PCR, mRNA levels of estrogen-responsive (ER) genes ERα1, ERα2, ERβ1, ERβ2 and NPR as well as two aromatase encoding genes (CYP19a and CYP19b) in goldfish (Carassius auratus L.) were measured during exposure to the GBWWTP effluent before and after MP UV/H2O2 treatment (a fluence of 1000 mJ/cm(2) and 20 mg/L of H2O2) in spring, summer and fall. Elevated expression of estrogen-responsive genes in goldfish exposed to UV/H2O2 treated effluent (a 7-day exposure) suggested that the UV/H2O2 Process may induce acute estrogenic disruption to goldfish principally because of the possible formation of various Oxidation by-products. However, prolonged exposure of goldfish (60 days) in UV/H2O2 treated effluent showed a restoration trend of ER gene expressions, especially in the summer. Collectively, our findings provide valuable indications regarding the long-term in vivo assessment of the MP UV/H2O2 Process for removing/degrading endocrine disrupting compounds detected in the municipal wastewater effluents.
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formation of disinfection by products in the ultraviolet chlorine Advanced Oxidation Process
Science of The Total Environment, 2015Co-Authors: Ding Wang, James R Bolton, Susan A Andrews, Ron HofmannAbstract:Disinfection by-product (DBP) formation may be a concern when applying ultraviolet light and free chlorine (UV/chlorine) as an Advanced Oxidation Process (AOP) for drinking water treatment, due to typically large chlorine doses (e.g. 5-10 mg L(-1) as free chlorine). A potential mitigating factor is the low chlorine contact times for this AOP treatment (e.g. seconds). Full-scale and pilot-scale test results showed minimal trihalomethane (THM) and haloacetic acid (HAA) formation during UV/chlorine treatment, while dichloroacetonitrile (DCAN) and bromochloroacetonitrile (BCAN) were produced rapidly. Adsorbable organic halide (AOX) formation was significant when applying the UV/chlorine Process in water that had not been previously chlorinated, while little additional formation was observed in prechlorinated water. Chlorine photolysis led to chlorate and bromate formation, equivalent to approximately 2-17% and 0.01-0.05% of the photolyzed chlorine, respectively. No perchlorate or chlorite formation was observed. During simulated secondary disinfection of AOP-treated water, DBP formation potential for THMs, HAAs, HANs, and AOX was observed to increase approximately to the same extent as was observed for pretreatment using the more common AOP of UV combined with hydrogen peroxide (UV/H2O2).
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application of a solar uv chlorine Advanced Oxidation Process to oil sands Process affected water remediation
Environmental Science & Technology, 2014Co-Authors: Zengquan Shu, James R Bolton, Miodrag Belosevic, Mohamed Gamal EldinAbstract:The solar UV/chlorine Process has emerged as a novel Advanced Oxidation Process for industrial and municipal wastewaters. Currently, its practical application to oil sands Process-affected water (OSPW) remediation has been studied to treat fresh OSPW retained in large tailings ponds, which can cause significant adverse environmental impacts on ground and surface waters in Northern Alberta, Canada. Degradation of naphthenic acids (NAs) and fluorophore organic compounds in OSPW was investigated. In a laboratory-scale UV/chlorine treatment, the NAs degradation was clearly structure-dependent and hydroxyl radical-based. In terms of the NAs degradation rate, the raw OSPW (pH ∼ 8.3) rates were higher than those at an alkaline condition (pH = 10). Under actual sunlight, direct solar photolysis partially degraded fluorophore organic compounds, as indicated by the qualitative synchronous fluorescence spectra (SFS) of the OSPW, but did not impact NAs degradation. The solar/chlorine Process effectively removed NAs (75-84% removal) and fluorophore organic compounds in OSPW in the presence of 200 or 300 mg L(-1) OCl(-). The acute toxicity of OSPW toward Vibrio fischeri was reduced after the solar/chlorine treatment. However, the OSPW toxicity toward goldfish primary kidney macrophages after solar/chlorine treatment showed no obvious toxicity reduction versus that of untreated OSPW, which warrants further study for Process optimization.
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photodegradation of emerging micropollutants using the medium pressure uv h2o2 Advanced Oxidation Process
Water Research, 2013Co-Authors: Zengquan Shu, James R Bolton, Miodrag Belosevic, Mohamed Gamalel DinAbstract:Abstract A medium-pressure (MP) ultraviolet (UV) Process has been applied to investigate the direct UV photolysis and UV/H2O2 Oxidation of selected model micropollutants (naproxen, carbamazepine, diclofenac, gemfibrozil, ibuprofen, caffeine, 2,4-D, 2,4-DCP, and mecoprop). The quantum yields were found to be between0.0010and 0.13 at pH = 7. In the MP UV/H2O2 Oxidation, the pseudo first-order rate constants for the selected compounds were found to be dependent on their initial concentrations (at mg/L levels) and on the H2O2 concentration. The UV doses required for 50% and 90% removal at various H2O2 levels varied widely among the compounds tested. Second-order rate constants (ranging from 4.1 × 109 to 1.4 × 1010 M−1 s−1) for the reaction between the selected compounds and hydroxyl radicals were determined using a competition-kinetics approach, where para-chlorobenzoic acid (pCBA) was chosen as the reference compound. Further, as an evaluation of electrical energy efficiency, the Figure-of-Merit, Electrical Energy per Order (EEO) was determined for the selected compounds using a batch reactor at 25 and 50 mg/L H2O2 concentrations. The electrical energy (in kWh) required to reduce a pollutant concentration by 90% ranged from 1.3 to 7.1 kWh m−3.
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a solar driven uv chlorine Advanced Oxidation Process
Water Research, 2012Co-Authors: Po Yee Chan, Mohamed Gamal Eldin, James R BoltonAbstract:Abstract An overlap of the absorption spectrum of the hypochlorite ion (OCl − ) and the ultraviolet (UV) end of the solar emission spectrum implies that solar photons can probably initiate the UV/chlorine Advanced Oxidation Process (AOP). The application of this solar Process to water and wastewater treatment has been investigated in this study. At the bench-scale, the OCl − photolysis quantum yield at 303 nm (representative of the lower end of the solar UV region) and at concentrations from 0 to 4.23 mM was 0.87 ± 0.01. Also the hydroxyl radical yield factor (for an OCl − concentration of 1.13 mM) was 0.70 ± 0.02. Application of this Process, at the bench-scale and under actual sunlight, led to methylene blue (MB) photobleaching and cyclohexanoic acid (CHA) photodegradation. For MB photobleaching, the OCl − concentration was the key factor causing an increase in the pseudo first-order rate constants. The MB photobleaching quantum yield was affected by the MB concentration, but not much by the OCl − concentration. For CHA photodegradation, an optimal OCl − concentration of 1.55 mM was obtained for a 0.23 mM CHA concentration, and a scavenger effect was observed when higher OCl − concentrations were applied. Quantum yields of 0.09 ± 0.01 and 0.89 ± 0.06 were found for CHA photodegradation and OCl − photolysis, respectively. In addition, based on the Air Mass 1.5 reference solar spectrum and experimental quantum yields, a theoretical calculation method was developed to estimate the initial rate for photoreactions under sunlight. The theoretical initial rates agreed well with the experimental rates for both MB photobleaching and CHA photodegradation.
Mohamed Gamal Eldin - One of the best experts on this subject based on the ideXlab platform.
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pilot scale uv h2o2 Advanced Oxidation Process for municipal reuse water assessing micropollutant degradation and estrogenic impacts on goldfish carassius auratus l
Water Research, 2016Co-Authors: Zengquan Shu, James R Bolton, Miodrag Belosevic, Arvinder Singh, Nikolaus Klamerth, Kerry N Mcphedran, Mohamed Gamal EldinAbstract:Low concentrations (ng/L-μg/L) of emerging micropollutant contaminants in municipal wastewater treatment plant effluents affect the possibility to reuse these waters. Many of those micropollutants elicit endocrine disrupting effects in aquatic organisms resulting in an alteration of the endocrine system. A potential candidate for tertiary municipal wastewater treatment of these micropollutants is ultraviolet (UV)/hydrogen peroxide (H2O2) as an Advanced Oxidation Process (AOP) which was currently applied to treat the secondary effluent of the Gold Bar Wastewater Treatment Plant (GBWWTP) in Edmonton, AB, Canada. A new approach is presented to predict the fluence-based degradation rate constants (kf') of environmentally occurring micropollutants including carbamazepine [(0.87-1.39) × 10(-3) cm(2)/mJ] and 2,4-Dichlorophenoxyacetic acid (2,4-D) [(0.60-0.91) × 10(-3) cm(2)/mJ for 2,4-D] in a medium pressure (MP) UV/H2O2 system based on a previous bench-scale investigation. Rather than using removal rates, this approach can be used to estimate the performance of the MP UV/H2O2 Process for degrading trace contaminants of concern found in municipal wastewater. In addition to the ability to track contaminant removal/degradation, evaluation of the MP UV/H2O2 Process was also accomplished by identifying critical ecotoxicological endpoints (i.e., estrogenicity) of the treated wastewater. Using quantitative PCR, mRNA levels of estrogen-responsive (ER) genes ERα1, ERα2, ERβ1, ERβ2 and NPR as well as two aromatase encoding genes (CYP19a and CYP19b) in goldfish (Carassius auratus L.) were measured during exposure to the GBWWTP effluent before and after MP UV/H2O2 treatment (a fluence of 1000 mJ/cm(2) and 20 mg/L of H2O2) in spring, summer and fall. Elevated expression of estrogen-responsive genes in goldfish exposed to UV/H2O2 treated effluent (a 7-day exposure) suggested that the UV/H2O2 Process may induce acute estrogenic disruption to goldfish principally because of the possible formation of various Oxidation by-products. However, prolonged exposure of goldfish (60 days) in UV/H2O2 treated effluent showed a restoration trend of ER gene expressions, especially in the summer. Collectively, our findings provide valuable indications regarding the long-term in vivo assessment of the MP UV/H2O2 Process for removing/degrading endocrine disrupting compounds detected in the municipal wastewater effluents.
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application of a solar uv chlorine Advanced Oxidation Process to oil sands Process affected water remediation
Environmental Science & Technology, 2014Co-Authors: Zengquan Shu, James R Bolton, Miodrag Belosevic, Mohamed Gamal EldinAbstract:The solar UV/chlorine Process has emerged as a novel Advanced Oxidation Process for industrial and municipal wastewaters. Currently, its practical application to oil sands Process-affected water (OSPW) remediation has been studied to treat fresh OSPW retained in large tailings ponds, which can cause significant adverse environmental impacts on ground and surface waters in Northern Alberta, Canada. Degradation of naphthenic acids (NAs) and fluorophore organic compounds in OSPW was investigated. In a laboratory-scale UV/chlorine treatment, the NAs degradation was clearly structure-dependent and hydroxyl radical-based. In terms of the NAs degradation rate, the raw OSPW (pH ∼ 8.3) rates were higher than those at an alkaline condition (pH = 10). Under actual sunlight, direct solar photolysis partially degraded fluorophore organic compounds, as indicated by the qualitative synchronous fluorescence spectra (SFS) of the OSPW, but did not impact NAs degradation. The solar/chlorine Process effectively removed NAs (75-84% removal) and fluorophore organic compounds in OSPW in the presence of 200 or 300 mg L(-1) OCl(-). The acute toxicity of OSPW toward Vibrio fischeri was reduced after the solar/chlorine treatment. However, the OSPW toxicity toward goldfish primary kidney macrophages after solar/chlorine treatment showed no obvious toxicity reduction versus that of untreated OSPW, which warrants further study for Process optimization.
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a solar driven uv chlorine Advanced Oxidation Process
Water Research, 2012Co-Authors: Po Yee Chan, Mohamed Gamal Eldin, James R BoltonAbstract:Abstract An overlap of the absorption spectrum of the hypochlorite ion (OCl − ) and the ultraviolet (UV) end of the solar emission spectrum implies that solar photons can probably initiate the UV/chlorine Advanced Oxidation Process (AOP). The application of this solar Process to water and wastewater treatment has been investigated in this study. At the bench-scale, the OCl − photolysis quantum yield at 303 nm (representative of the lower end of the solar UV region) and at concentrations from 0 to 4.23 mM was 0.87 ± 0.01. Also the hydroxyl radical yield factor (for an OCl − concentration of 1.13 mM) was 0.70 ± 0.02. Application of this Process, at the bench-scale and under actual sunlight, led to methylene blue (MB) photobleaching and cyclohexanoic acid (CHA) photodegradation. For MB photobleaching, the OCl − concentration was the key factor causing an increase in the pseudo first-order rate constants. The MB photobleaching quantum yield was affected by the MB concentration, but not much by the OCl − concentration. For CHA photodegradation, an optimal OCl − concentration of 1.55 mM was obtained for a 0.23 mM CHA concentration, and a scavenger effect was observed when higher OCl − concentrations were applied. Quantum yields of 0.09 ± 0.01 and 0.89 ± 0.06 were found for CHA photodegradation and OCl − photolysis, respectively. In addition, based on the Air Mass 1.5 reference solar spectrum and experimental quantum yields, a theoretical calculation method was developed to estimate the initial rate for photoreactions under sunlight. The theoretical initial rates agreed well with the experimental rates for both MB photobleaching and CHA photodegradation.
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assessment of the uv chlorine Process as an Advanced Oxidation Process
Water Research, 2011Co-Authors: Jing Jin, Mohamed Gamal Eldin, James R BoltonAbstract:Abstract Several organic compounds were used as radical scavengers/reagents to investigate the possibility of the UV/chlorine Process being used as an Advanced Oxidation Process (AOP) in the treatment of drinking water and wastewater. The UV/H 2 O 2 Process was selected as a reference, so that the results from the UV/chlorine Process could be compared with those of the UV/H 2 O 2 Process. Methanol was added to active chlorine solutions at both pH 5 and 10 and into hydrogen peroxide samples. The photodegradation quantum yields and the OH radical production yield factors, which are significant in evaluating AOPs, were calculated for both the UV/chlorine and the UV/H 2 O 2 Processes. The yield factor for the UV/chlorine Process at pH 5 was 0.46 ± 0.09, which is much lower than that of the UV/H 2 O 2 Process, which reached 0.85 ± 0.04. In addition to methanol, para -chlorobenzoic acid ( p CBA) and cyclohexanoic acid (CHA) were added to active chlorine solutions and to H 2 O 2 solutions, to evaluate the efficiencies of oxidizing these organic compounds. The specific first-order reaction rate constants for the Oxidation of p CBA and CHA, using the UV/chlorine Process, were lower than those found using the UV/H 2 O 2 Process.
P H Liao - One of the best experts on this subject based on the ideXlab platform.
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disinfection and solubilization of sewage sludge using the microwave enhanced Advanced Oxidation Process
Journal of Hazardous Materials, 2010Co-Authors: Winnie I Chan, P H LiaoAbstract:The microwave enhanced Advanced Oxidation Process (MW/H(2)O(2)-AOP) was used to treat municipal sewage sludge for solids disintegration, nutrient solubilization, with an emphasis on pathogen destruction and regrowth. Pathogen reduction, in terms of fecal coliform concentrations were found below detection limit (1000 CFU/L) immediately after treatment when sludge was treated at 70 degrees C with more than 0.04% of H(2)O(2) (w/w). Significant regrowth of fecal coliforms was observed for the treated samples after 72 h. However, no regrowth was observed for samples treated at 70 degrees C with 0.08% H(2)O(2) or higher, suggesting a complete elimination of fecal coliforms. The range of hydrogen peroxide used did not have a significant effect on orthophosphate release regardless of temperature. Ammonia release at these low temperatures was found to be insignificant. The soluble chemical oxygen demand increased with an increase of hydrogen peroxide dosage at 70 degrees C. However, there was no clear trend of soluble chemical oxygen demand over varying hydrogen peroxide dosage at 55 degrees C. The MW/H(2)O(2)-AOP is a novel Process for the pasteurization and stabilization of sewage sludge to meet and maintain Class A biosolids criteria.
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factors affecting nutrient solubilization from sewage sludge using microwave enhanced Advanced Oxidation Process
Journal of Environmental Science and Health Part A-toxic\ hazardous Substances & Environmental Engineering, 2007Co-Authors: Wayne T Wong, P H LiaoAbstract:A microwave-enhanced Advanced Oxidation Process using hydrogen peroxide (MW-H2O2-AOP) was used for the solubilization of phosphate and ammonia from secondary municipal sludge. Two sets of experiments were performed to determine the factors affecting nutrient solubilization from sewage sludge. Four factors—microwave heating temperature, heating time, hydrogen peroxide treatment, and sulphuric acid treatment—were incorporated into a screening design to determine which factors were significant for maximizing nutrient solubilization. For phosphorus, the three most significant factors, following the order of significance, were (i) microwave heating temperature, (ii) the combined effect of microwave heating temperature and hydrogen peroxide hydrogen peroxide addition, (iii) microwave heating temperature, and (iv) sulphuric acid addition.
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sludge reduction and volatile fatty acid recovery using microwave Advanced Oxidation Process
Journal of Environmental Science and Health Part A-toxic\ hazardous Substances & Environmental Engineering, 2007Co-Authors: P H Liao, Winnie I Chan, Wayne T WongAbstract:Sewage sludge was subjected to the combined microwave-hydrogen peroxide-sulfuric acid enhanced Advanced Oxidation Process (MW-H2O2-H+-AOP) to evaluate the potential of reducing suspended solids in sludge. The soluble chemical oxygen demand (SCOD) and acetic acid produced were dependent on the amounts of H2O2 and acid used in the Process. For sewage sludge, a higher volume of H2O2 addition not only favored the destruction of sludge solids, but also conserved the carbon content in the medium. Volatile fatty acid (VFA) concentrations also increased with the amount of inorganic acid in the solution. For the soluble fraction of solutions derived from microwave-treated sludge, over 96% of the total COD was in the soluble form, and up to 25% of this soluble COD was acetic acid. The presence of an inorganic acid was a stability factor in retaining the SCOD in solution, instead of the formation of carbon dioxide, resulting in reduced total COD in the solutions. By controlling the amounts of H2O2 and acid addition,...
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a hydrogen peroxide microwave Advanced Oxidation Process for sewage sludge treatment
Journal of Environmental Science and Health Part A-toxic\ hazardous Substances & Environmental Engineering, 2006Co-Authors: Wayne T Wong, Winnie I Chan, P H LiaoAbstract:This study focused on the efficacy of the microwave/hydrogen peroxide Advanced Oxidation Process (MW/H2O2–AOP) on the secondary sludge treatment. The results indicated that at temperatures of 80°C and above, essentially all of the chemical oxygen demand (COD) was solubilized by the combined MW/H2O2–AOP. This Process also solubilized nutrients (nitrogen, phosphorus and metals) from sludge which can be extracted for other purposes, such as struvite crystallization. Based on a stoichiometric molar ratio of 1:1:1 for Mg:NH3:PO4, ammonia was found to be the limiting nutrient without any H2O2 addition in the Process at all temperatures. With the addition of H2O2, ortho-phosphate became the limiting nutrient. In all treatments, magnesium was non-limiting, thus magnesium addition is not required for subsequent struvite crystallization. The MW/H2O2–AOP also enhanced the pasteurization or sterilization of sludge. The MW/H2O2–AOP provides novel sludge management options for the wastewater industry, not only in solub...
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Advanced Oxidation Process using hydrogen peroxide microwave system for solubilization of phosphate
Journal of Environmental Science and Health Part A-toxic\ hazardous Substances & Environmental Engineering, 2005Co-Authors: P H Liao, Wayne T WongAbstract:An Advanced Oxidation Process (AOP) combining hydrogen peroxide and microwave heating was used for the solubilization of phosphate from secondary municipal sludge from an enhanced biological phosphorus removal Process. The microwave irradiation is used as a generator agent of oxidizing radicals as well as a heating source in the Process. This AOP Process could facilitate the release of a large amount of the sludge-bound phosphorus from the sewage sludge. More than 84% of the total phosphorous could be released at a microwave heating time of 5 min at 170°C. This innovative Process has the potential of being applied to simple sludge treatment Processes in domestic wastewater treatment and to the recovery of phosphorus from the wastewater.
Naiyun Gao - One of the best experts on this subject based on the ideXlab platform.
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degradation of phenacetin by the uv chlorine Advanced Oxidation Process kinetics pathways and toxicity evaluation
Chemical Engineering Journal, 2018Co-Authors: Yanping Zhu, Naiyun Gao, Wenhai Chu, Shi ChenAbstract:Abstract The degradation of phenacetin (PNT) by the combination of low-pressure mercury lamp and chlorine (UV/chlorine), an Advanced Oxidation Process (AOP) of recent interest, was systematically investigated in terms of degradation kinetics, effects of chlorine dosage and water parameters, Oxidation products as well as toxicity evaluation. The degradation of PNT followed pseudo first-order kinetics. The first-order rate constant ( k obs ) in the UV/chlorine AOP was 4.3, 8.4, and 11.1 times that of dark chlorination, UV/H 2 O 2 , and UV/PS, respectively, with the same molar dosage of oxidant at pH 7.2. Radical quenching tests suggested that chlorination, OH and reactive chlorine species were responsible for the UV/chlorine Oxidation of PNT with contributions of 26.33%, 14.6% and 59.07%, at pH 7.2. As chlorine dosage gradually increased from 100 to 500 μM, the corresponding k obs monotonically increased from 0.0229 to 0.216 min −1 . k obs was not apparently affected by the pH and coexisting chloride, but decreased by 56.5% and 75.4% in the presence of 10 mM HCO 3 − and 10 mg/L NOM. Slight decreases (around 15%) of k obs occurred in the raw water and tap water tests, while little effect was observed in filtered water samples compared with ultrapure water tests. Six typical disinfection byproducts including trichloromethane (TCM), chloral hydrate, dichloropropanone, trichloropropanone, trichloronitromethane, and dichloroacetonitrile were detected. The TCM yields increased to 159.95 μg/L within 20 min reaction of UV/chlorine, comprising 13.3% of the degraded PNT (per mole of carbon). The acute toxicity to luminescent bacterium Q67 by UV/chlorine was lower than chlorination under similar reaction conditions.
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degradation of carbamazepine by uv chlorine Advanced Oxidation Process and formation of disinfection by products
Environmental Science and Pollution Research, 2016Co-Authors: Shiqing Zhou, Ying Xia, Tian Yao, Zhou Shi, Shumin Zhu, Naiyun GaoAbstract:Pharmaceuticals in water are commonly found and are not efficiently removed by current treatment Processes. Degradation of antiepileptic drug carbamazepine (CBZ) by UV/chlorine Advanced Oxidation Process was systematically investigated in this study. The results showed that the UV/chlorine Process was more effective at degrading CBZ than either UV or chlorination alone. The CBZ degradation followed pseudo-first order reaction kinetics, and the degradation rate constants (kobs) were affected by the chlorine dose, solution pH, and natural organic matter concentration to different degrees. Degradation of CBZ greatly increased with increasing chlorine dose and decreasing solution pH during the UV/chlorine Process. Additionally, the presence of natural organic matter in the solution inhibited the degradation of CBZ. UV photolysis, chlorination, and reactive species (hydroxyl radical •OH and chlorine atoms •Cl) were identified as responsible for CBZ degradation in the UV/chlorine Process. Finally, a degradation pathway for CBZ in the UV/chlorine Process was proposed and the formation potentials of carbonaceous and nitrogenous disinfection by-products were evaluated. Enhanced formation of trichloroacetic acid, dichloroacetonitrile, and trichloronitromethane precursors should be considered when applying UV/chlorine Advanced Oxidation Process to drinking water.
Shane A Snyder - One of the best experts on this subject based on the ideXlab platform.
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on line sensor monitoring for chemical contaminant attenuation during uv h2o2 Advanced Oxidation Process
Water Research, 2015Co-Authors: Tarun Anumol, Shane A Snyder, Minkyu Park, Ian L Pepper, Jens ScheidelerAbstract:A combination of surrogate parameters and indicator compounds were measured to predict the removal efficiency of trace organic compounds (TOrCs) using low pressure (LP)-UV/H2O2 Advanced Oxidation Process (AOP), engaged with online sensor-based monitoring system. Thirty-nine TOrCs were evaluated in two distinct secondary wastewater effluents in terms of estimated photochemical reactivity, as a function of the rate constants of UV direct photolysis (kUV) and hydroxyl radical (OH) Oxidation (kOH). The selected eighteen TOrCs were classified into three groups that served as indicator compounds: Group 1 for photo-susceptible TOrCs but with minor degradation by OH Oxidation (diclofenac, fluoxetine, iohexol, iopamidol, iopromide, simazine and sulfamethoxazole); Group 2 for TOrCs susceptible to both direct photolysis and OH Oxidation (benzotriazole, diphenhydramine, ibuprofen, naproxen and sucralose); and Group 3 for photo-resistant TOrCs showing dominant degradation by OH Oxidation (atenolol, carbamazepine, DEET, gemfibrozil, primidone and trimethoprim). The results indicate that TOC (optical-based measurement), UVA254 or UVT254 (UV absorbance or transmittance at 254 nm), and total fluorescence can all be used as suitable on-line organic surrogate parameters to predict the attenuation of TOrCs. Furthermore, the automated real-time monitoring via on-line surrogate sensors and equipped with the developed degradation profiles between sensor response and a group of TOrCs removal can provide a diagnostic tool for Process control during Advanced treatment of reclaimed waters.
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an evaluation of a pilot scale nonthermal plasma Advanced Oxidation Process for trace organic compound degradation
Water Research, 2010Co-Authors: Daniel Gerrity, Benjamin D Stanford, Rebecca A Trenholm, Shane A SnyderAbstract:This study evaluated a pilot-scale nonthermal plasma (NTP) Advanced Oxidation Process (AOP) for the degradation of trace organic compounds such as pharmaceuticals and potential endocrine disrupting compounds (EDCs). The degradation of seven indicator compounds was monitored in tertiary-treated wastewater and spiked surface water to evaluate the effects of differing water qualities on Process efficiency. The tests were also conducted in batch and single-pass modes to examine contaminant degradation rates and the remediation capabilities of the technology, respectively. Values for electrical energy per order (EEO) of magnitude degradation ranged from <0.3 kWh/m(3)-log for easily degraded compounds (e.g., carbamazepine) in surface water to 14 kWh/m(3)-log for more recalcitrant compounds (e.g., meprobamate) in wastewater. Changes in the bulk organic matter based on UV(254) absorbance and excitation-emission matrices (EEM) were also monitored and correlated to contaminant degradation. These results indicate that NTP may be a viable alternative to more common AOPs due to its comparable energy requirements for contaminant degradation and its ability to operate without any additional feed chemicals.
