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Sustainability assessment of wastewater and sludge treatment techniques for removal of compounds from Pharmaceuticals and Personal Care Products (PPCPs)Tarpani, Raphael January 2017 (has links)
Environmental releases of chemical compounds from Pharmaceuticals and Personal Care Products (PPCPs) are receiving growing attention in the scientific community. Most research suggests that the main pathway for these substances to reach the environment is via Wastewater Treatment Plants (WWTPs) due to the effluents from households, industry and hospitals, which can contain substantial amounts of these compounds. Many of these contaminants are poorly treated in conventional WWTPs and are often discharged into the environment with the effluent and sludge, posing ecotoxicological risks to the wildlife and humans. Therefore, it is necessary to limit their release into the environment by controlling their discharge from WWTPs. This can be achieved by adopting advanced wastewater treatment techniques, currently not used as there are no legislative limits on PPCP compounds. However, as the scientific evidence is growing on their adverse impacts, it is only a matter of time before their advanced treatment becomes compulsory. To help guide future developments and inform policy in this area, this work considered a range of advanced treatment techniques with the aim of identifying the most sustainable options. Adopting a life cycle approach and considering all three dimensions of sustainability (economic, environmental and social), nine technologies were assessed on sustainability: four for WWTP effluent and five for sludge treatment. The advanced wastewater treatment methods considered are: (i) granular activated carbon, (ii) nanofiltration, (iii) solar photo-Fenton, and (iv) ozonation. The sludge treatment techniques comprise: (i) anaerobic digestion of sludge for agricultural application; (ii) sludge composting, also for agricultural application; (iii) incineration; (iv) pyrolysis; and (v) wet air oxidation. They were assessed on sustainability using over 28 indicators, some of which were also used to evaluate the implication of different treatment techniques for the energy-water-food (EWF) nexus. Multi-Criteria Decision Analysis (MCDA) was applied to aggregate the sustainability indicators into an overall sustainability index for each alternative and identify the most sustainable option(s). The results suggest that, among the four techniques considered for advanced effluent treatment, nanofiltration and granular activated carbon have the lowest life cycle environmental impacts. Although not preferable at all operating ranges, they have the lowest burdens and are, overall, most sustainable. The latter also has the lowest impact on the EWF nexus at mean operating parameter, and is the preferred option as the treated effluent can be used for potable water due lower concerns over the presence of PPCPs. However, the results also suggest that, from the ecotoxicological point of view, there is little benefit in using any of the advanced wastewater treatment techniques assessed. This is due to the life cycle ecotoxicological impacts from the treatment itself being similar or even higher than for the effluent released into the environment untreated. For sludge treatments, anaerobic digestion and pyrolysis are environmentally and economically preferable techniques. The former is the best with respect to the EWF nexus due to the recovery of energy and agricultural fertilizers. In relation to social aspects, wet air oxidation is amongst the most desirable for high resource recovery, together with the two former techniques. The heavy metals content in the sludge applied on agricultural soils is a major concern for freshwater ecotoxicity potential, posing risks orders of magnitude higher than PPCP compounds.
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Atmospheric modeling and experimental characterization of gas and aerosol phase cyclic volatile methyl siloxanesJanechek, Nathan Joseph 01 August 2018 (has links)
Cyclic volatile methyl siloxanes (cVMS) are anthropogenic chemicals present in a range of consumer personal care products such as antiperspirants and lotions. They are highly volatile, and readily released to the atmosphere by personal care product use. Generally unreactive, they are found in high concentrations in indoor environments, and transported long distances in the atmosphere. A major removal pathway for these silicon-containing gases is reaction with the OH radical, which has been recently shown to yield secondary Si-containing aerosol compounds in addition to the gas phase products. Despite the significance of the atmospheric fate of these compounds, much of the previous work has focused on the aquatic fate, and almost exclusively on the parent compounds. The oxidation products and potential aerosol species have received much less attention, with almost no ambient measurements or experimental physical property data. This work investigates cVMS with a focus on providing much needed information on potential loadings of the oxidation products, their distribution, and particle phase properties using an atmospheric model and laboratory experiments. Specifically, cVMS was added to the Community Multiscale Air Quality (CMAQ) model; expected concentrations, spatial distribution, and seasonal trends were quantified; cVMS secondary aerosols generated and physical properties characterized; and secondary aerosol parameters for atmospheric modeling developed.
The CMAQ model code was modified to update the chemical mechanism with cVMS, develop emissions, boundary, and deposition parameters to simulate four separate seasons at a spatial resolution of 36 km over North America. Typical model concentrations showed parent compounds were highly dependent on population density as cities had monthly averaged peak decamethylcyclopentasiloxane (D5) concentrations up to 432 ng m−3. Peak oxidized D5 concentrations were significantly less, up to 9 ng m−3, and were located downwind of major urban areas. Model results were compared to available measurements and previous simulation results. Parent compound concentrations in urban locations were sensitive to transport factors, while parent compounds in rural areas and oxidized product concentrations were influenced by large-scale seasonal variability in OH.
Secondary aerosols were formed by reacting cVMS gas in an oxidation flow reactor. The particles were characterized for concentration, size, aerosol yield, morphology, energy-dispersive spectroscopy (EDS) individual particle chemical composition, hygroscopicity (cloud condensation nuclei formation potential), and volatility. Aerosol concentrations were 68 – 220 µg m-3 with aerosol mass fractions (i.e. yields) of 0.22-0.50. Aerosol yield was sensitive to chamber OH, indicating an interplay between oxidation conditions and the concentration of lower volatility species. The D5 oxidation products were non-volatile, with only the smallest particles (10 nm) exhibiting more than 4% of diameter decrease upon heating to 190°C temperature. The D5 oxidation aerosols were relatively non-hygroscopic, with average hygroscopicity kappa of ~0.01.
Experimental data was analyzed to develop secondary aerosol parameters for the CMAQ model. Chamber yield data was fit to a two-product Odum volatility model with yield values of 0.14 and 0.82, corresponding to saturation concentrations of 0.95 and 484 µg m-3, respectively. The recommended enthalpy of vaporization is 18 kJ mol-1 based on other modeled secondary organic aerosol. Recommended molecular weights for the D5 low volatility Odum, high volatility Odum, and non-volatile oligomerization species are 588, 373, and 733 g mol-1 corresponding to OH substituted ring-opened, monomer, and dimer species, respectively.
This work provides simulations of expected concentrations, spatial patterns, and seasonal influence of the parent and oxidized cVMS species to extend beyond the few parent cVMS measurements and nonexistent oxidation product measurements. The modeling work serves as an important tool to guide future field measurements especially important for the confirmation of particle phase oxidation products. Extensive aerosol characterization measurements provide much needed physical property data important for future modeling, risk, and exposure studies.
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The Fate of Pharmaceuticals and Personal Care Products in Conventional and Engineered On-Site Wastewater Drain FieldsBeardall, James 01 May 2015 (has links)
Utah State University Division of Environmental Engineering student, under the direction of Ms. Judith L. Sims, has investigated the fate of six pharmaceuticals and personal care products (PPCPs) in conventional and engineered on-site wastewater drain fields. The presence of PPCPs in the environment, especially in aquatic environments, has raised awareness to the effects of PPCPs on aquatic life and the fate of these PPCPs, and has caused regulators to become more involved in setting requirements for the removal of PPCPs from wastewater.
This research investigated the fate of caffeine, acetaminophen, carbamazepine, sulfamethoxazole, progesterone, and fluoxetine in laboratory scaled columns that simulate conventional pipe and gravel on-site wastewater drain fields as well as engineered columns similar to the pipe and gravel simulated columns, but with the addition of media below the gravel layer to enhance PPCP removal via sorption and biodegradation. Results from the month long experiment showed that sulfamethoxazole removal in the columns representing conventional systems peaked at 74%. The other PPCPs were non-detectable. Sulfamethoxazole removal increased to 81% in columns engineered with a layer of sphagnum peat moss beneath the gravel layer and below the method detection limit (5.5 ng/mL) in columns engineered with a layer of charred straw beneath the gravel layer. No other PPCPs analyzed from the engineered columns were detected. Batch experiments indicated that sorption is the main mechanism for PPCP removal with the exception of progesterone, where biodegradation is a major mechanism.
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Evaluating the Effectiveness of Three Utah Wastewater Treatment Facilities in Removing Pharmaceuticals and Personal Care ProductsRoth, Oksana 01 May 2012 (has links)
The occurrence of Pharmaceuticals and Personal Care Products (PPCPs) in surface waters has become a growing concern within the last decade although the first mention of human PPCPs in the environment goes back to late 1970s. Pharmaceuticals include prescription drugs, over-the-counter medications, and veterinary drugs. Personal care products include products such as lotions, fragrances, and soaps. In addition to traditional personal care products, the term PPCPs has been adopted to represent a wide variety of chemicals used in consumer products including plasticizers and fire retardants. Wastewater effluents are thought to be the main source of PPCPs in surface waters since most pharmaceuticals and personal care products eventually are disposed of, directly or indirectly, into domestic sewage systems that are not specifically designed to treat them.
This thesis research examined the occurrence and removal of ten PPCPs in three Utah wastewater treatment plants (WWTPs) in the State of Utah. The ten PPCPs (caffeine, acetaminophen, sulfamethoxazole, tris(2-chloroethyl) phosphate, carbamazepine, estrone, progesterone, gemfibrozil, 4-n-nonylphenol, and bis(2- ethylhexyl) phthalate) were selected for this study based on their chemical properties, environmental concern due to their widespread use, frequent detection in natural water, wastewater, and biosolids, and potential risk to the environmental and human health. The selected treatment technologies, represented by Brigham, Hyrum, and Spanish Fork WWTPs, were oxidation ditches, membrane bioreactors, and trickling filters. Influent, effluent and biosolids samples were collected in May, July, and August of 2011. The highest influent concentrations were measured for caffeine (3.9 – 15.4 μg/L) and acetaminophen (7.4 – 71.5 μg/L). Sulfamethoxazole, tris(2-chloroethyl) phosphate, and carbamazepine were measured in the effluent of all three WWTPs. Removal efficiencies calculated from differences between influent and effluent concentrations were caffeine (>80%), acetaminophen (>99%), and sulfamethoxazole (>60%). Tris(2-chloroethyl) phosphate, carbamazepine, and bis(2-ethylhexyl) phthalate were not consistently found above the method limits of quantitation (LOQs). The effluent concentrations of the measured PPCPs were below the levels of concern suggested by available toxicity data.
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A Bench-scale Evaluation of the Removal of Selected Pharmaceuticals and Personal Care Products by UV and UV/H₂O₂ in Drinking Water TreatmentCrosina, Quinn Kathleen 12 1900 (has links)
A bench-scale study of the degradation of four selected pharmaceuticals and personal care products (PPCPs) was carried out using UV and UV/H₂O₂ treatment employing low pressure (LP) and medium pressure (MP) lamps. The target substances included the pharmaceutical compounds ibuprofen, naproxen, and gemfibrozil, along with the bactericide triclosan. There were four main objectives of the study, as follows: to evaluate the removal of the target compounds using UV irradiation alone and UV/H₂O₂, to determine the reaction kinetics for direct and indirect photolysis of each selected compound, to determine the influence of major water quality parameters on the efficacy of treatment, and to compare the applied UV and UV/H₂O₂ doses to those that have been found to be effective for disinfection and removal of taste and odour compounds, respectively.
For initial ultra-pure water experiments the target compounds were spiked at concentrations of approximately 250 µg/L (~1 µM). In latter ultra-pure water experiments and in the partially-treated water experiments, the selected PPCPs were spiked at a lower range (c~500-1000 ng/L), which is more representative of reported environmental concentrations. In an ultra-pure water matrix, a high LP fluence of 1000 mJ/cm² caused only triclosan to substantially degrade. Furthermore, with LP-UV/H₂O₂ only triclosan and naproxen had average percent removals above 60% at a typical disinfection fluence of 40 mJ/cm² with 100 mg/L H₂O₂. Complete degradation of all four compounds in ultra-pure water was achieved with very high fluences (compared to those used for UV disinfection) with MP-UV alone (at or above 1000 mJ/cm²) or with relatively high fluences for MP-UV/H₂O₂ (200-300 mJ/cm²) with 10 mg/L H₂O₂. Overall, when compared at similar applied fluences, the MP lamp was much more effective than the LP lamp. Furthermore, the addition of H₂O₂ typically increased removal rates, in some cases substantially, through formation and subsequent reaction of the PPCP with the •OH radical.
When target substances were treated all together in an ultra-pure water solution, removals were lower than when they were treated independently at the same individual concentrations (~250 µg/L) this may simply have been the result of a higher total contaminant concentration in solution, which lessened the availability of the •OH radical and incident UV irradiation for degradation of all compounds. On the other hand, removals were improved when the combined target compounds were present at a lower individual concentration range (~750 ng/L), which suggests that removals may be concentration driven, with reduced matrix effects seen at lower overall contaminant concentrations. Furthermore, during the partially-treated water experiments, variability in treatment performance was observed with differing water quality; however, it was not evident which specific quality parameters influenced treatment effectiveness. On the other hand, substantial and sometimes complete, degradation of the target compounds was still seen in the partially-treated water with high MP-UV/H₂O₂ doses (e.g. 300 mJ/cm² + 10 mg/L H₂O₂ and 500 + 10 mg/L H₂O₂).
For the kinetic experiments, compounds were spiked individually in ultra-pure water (c~250 µg/L = ~1µM). The photolysis of the target compounds during treatment was assumed to be a pseudo-first-order reaction. Kinetic parameters were determined for both direct and indirect photolysis for both lamps. The calculated rate constants confirmed the importance of •OH radicals for degradation of these compounds, especially for ibuprofen and gemfibrozil. For ibuprofen and gemfibrozil, direct photolysis rate constants could not be determined for LP-UV because very little degradation was seen at the fluences tested. LP-UV direct phototlysis rate constants for naproxen and triclosan were 0.0002 and 0.0033 cm²/mJ, respectively. Overall rate constants describing degradation of the four compounds due to LP-UV/H₂O₂ ranged from 0.0049 to 0.0124 cm²/mJ. All four compounds had fluence-based reaction rate constants for MP-UV indirect photolysis of approximately 0.01 cm²/mJ, while MP-UV direct photolysis rate constants ranged between 0.0007-0.007 cm²/mJ, with ibuprofen having the lowest and triclosan the highest.
The overall trends were similar to those seen by other researchers for the removal of taste and odour compounds. For example, fluences required for substantial removal were much higher than typical disinfection doses, the MP lamp was more effective than the LP lamp (when compared solely on a fluence-basis), and the addition of H₂O₂ improved removals.
On the whole, UV/H₂O₂ appears to be a very promising technology for the removal of these selected PPCPs during drinking water treatment, and is likely to be equally effective for other, similar contaminants.
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A Bench-scale Evaluation of the Removal of Selected Pharmaceuticals and Personal Care Products by UV and UV/H₂O₂ in Drinking Water TreatmentCrosina, Quinn Kathleen 12 1900 (has links)
A bench-scale study of the degradation of four selected pharmaceuticals and personal care products (PPCPs) was carried out using UV and UV/H₂O₂ treatment employing low pressure (LP) and medium pressure (MP) lamps. The target substances included the pharmaceutical compounds ibuprofen, naproxen, and gemfibrozil, along with the bactericide triclosan. There were four main objectives of the study, as follows: to evaluate the removal of the target compounds using UV irradiation alone and UV/H₂O₂, to determine the reaction kinetics for direct and indirect photolysis of each selected compound, to determine the influence of major water quality parameters on the efficacy of treatment, and to compare the applied UV and UV/H₂O₂ doses to those that have been found to be effective for disinfection and removal of taste and odour compounds, respectively.
For initial ultra-pure water experiments the target compounds were spiked at concentrations of approximately 250 µg/L (~1 µM). In latter ultra-pure water experiments and in the partially-treated water experiments, the selected PPCPs were spiked at a lower range (c~500-1000 ng/L), which is more representative of reported environmental concentrations. In an ultra-pure water matrix, a high LP fluence of 1000 mJ/cm² caused only triclosan to substantially degrade. Furthermore, with LP-UV/H₂O₂ only triclosan and naproxen had average percent removals above 60% at a typical disinfection fluence of 40 mJ/cm² with 100 mg/L H₂O₂. Complete degradation of all four compounds in ultra-pure water was achieved with very high fluences (compared to those used for UV disinfection) with MP-UV alone (at or above 1000 mJ/cm²) or with relatively high fluences for MP-UV/H₂O₂ (200-300 mJ/cm²) with 10 mg/L H₂O₂. Overall, when compared at similar applied fluences, the MP lamp was much more effective than the LP lamp. Furthermore, the addition of H₂O₂ typically increased removal rates, in some cases substantially, through formation and subsequent reaction of the PPCP with the •OH radical.
When target substances were treated all together in an ultra-pure water solution, removals were lower than when they were treated independently at the same individual concentrations (~250 µg/L) this may simply have been the result of a higher total contaminant concentration in solution, which lessened the availability of the •OH radical and incident UV irradiation for degradation of all compounds. On the other hand, removals were improved when the combined target compounds were present at a lower individual concentration range (~750 ng/L), which suggests that removals may be concentration driven, with reduced matrix effects seen at lower overall contaminant concentrations. Furthermore, during the partially-treated water experiments, variability in treatment performance was observed with differing water quality; however, it was not evident which specific quality parameters influenced treatment effectiveness. On the other hand, substantial and sometimes complete, degradation of the target compounds was still seen in the partially-treated water with high MP-UV/H₂O₂ doses (e.g. 300 mJ/cm² + 10 mg/L H₂O₂ and 500 + 10 mg/L H₂O₂).
For the kinetic experiments, compounds were spiked individually in ultra-pure water (c~250 µg/L = ~1µM). The photolysis of the target compounds during treatment was assumed to be a pseudo-first-order reaction. Kinetic parameters were determined for both direct and indirect photolysis for both lamps. The calculated rate constants confirmed the importance of •OH radicals for degradation of these compounds, especially for ibuprofen and gemfibrozil. For ibuprofen and gemfibrozil, direct photolysis rate constants could not be determined for LP-UV because very little degradation was seen at the fluences tested. LP-UV direct phototlysis rate constants for naproxen and triclosan were 0.0002 and 0.0033 cm²/mJ, respectively. Overall rate constants describing degradation of the four compounds due to LP-UV/H₂O₂ ranged from 0.0049 to 0.0124 cm²/mJ. All four compounds had fluence-based reaction rate constants for MP-UV indirect photolysis of approximately 0.01 cm²/mJ, while MP-UV direct photolysis rate constants ranged between 0.0007-0.007 cm²/mJ, with ibuprofen having the lowest and triclosan the highest.
The overall trends were similar to those seen by other researchers for the removal of taste and odour compounds. For example, fluences required for substantial removal were much higher than typical disinfection doses, the MP lamp was more effective than the LP lamp (when compared solely on a fluence-basis), and the addition of H₂O₂ improved removals.
On the whole, UV/H₂O₂ appears to be a very promising technology for the removal of these selected PPCPs during drinking water treatment, and is likely to be equally effective for other, similar contaminants.
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A Bench-scale Evaluation of the Removal of Selected Pharmaceuticals and Personal Care Products by UV and UV/H₂O₂ in Drinking Water TreatmentCrosina, Quinn Kathleen 12 1900 (has links)
A bench-scale study of the degradation of four selected pharmaceuticals and personal care products (PPCPs) was carried out using UV and UV/H₂O₂ treatment employing low pressure (LP) and medium pressure (MP) lamps. The target substances included the pharmaceutical compounds ibuprofen, naproxen, and gemfibrozil, along with the bactericide triclosan. There were four main objectives of the study, as follows: to evaluate the removal of the target compounds using UV irradiation alone and UV/H₂O₂, to determine the reaction kinetics for direct and indirect photolysis of each selected compound, to determine the influence of major water quality parameters on the efficacy of treatment, and to compare the applied UV and UV/H₂O₂ doses to those that have been found to be effective for disinfection and removal of taste and odour compounds, respectively.
For initial ultra-pure water experiments the target compounds were spiked at concentrations of approximately 250 µg/L (~1 µM). In latter ultra-pure water experiments and in the partially-treated water experiments, the selected PPCPs were spiked at a lower range (c~500-1000 ng/L), which is more representative of reported environmental concentrations. In an ultra-pure water matrix, a high LP fluence of 1000 mJ/cm² caused only triclosan to substantially degrade. Furthermore, with LP-UV/H₂O₂ only triclosan and naproxen had average percent removals above 60% at a typical disinfection fluence of 40 mJ/cm² with 100 mg/L H₂O₂. Complete degradation of all four compounds in ultra-pure water was achieved with very high fluences (compared to those used for UV disinfection) with MP-UV alone (at or above 1000 mJ/cm²) or with relatively high fluences for MP-UV/H₂O₂ (200-300 mJ/cm²) with 10 mg/L H₂O₂. Overall, when compared at similar applied fluences, the MP lamp was much more effective than the LP lamp. Furthermore, the addition of H₂O₂ typically increased removal rates, in some cases substantially, through formation and subsequent reaction of the PPCP with the •OH radical.
When target substances were treated all together in an ultra-pure water solution, removals were lower than when they were treated independently at the same individual concentrations (~250 µg/L) this may simply have been the result of a higher total contaminant concentration in solution, which lessened the availability of the •OH radical and incident UV irradiation for degradation of all compounds. On the other hand, removals were improved when the combined target compounds were present at a lower individual concentration range (~750 ng/L), which suggests that removals may be concentration driven, with reduced matrix effects seen at lower overall contaminant concentrations. Furthermore, during the partially-treated water experiments, variability in treatment performance was observed with differing water quality; however, it was not evident which specific quality parameters influenced treatment effectiveness. On the other hand, substantial and sometimes complete, degradation of the target compounds was still seen in the partially-treated water with high MP-UV/H₂O₂ doses (e.g. 300 mJ/cm² + 10 mg/L H₂O₂ and 500 + 10 mg/L H₂O₂).
For the kinetic experiments, compounds were spiked individually in ultra-pure water (c~250 µg/L = ~1µM). The photolysis of the target compounds during treatment was assumed to be a pseudo-first-order reaction. Kinetic parameters were determined for both direct and indirect photolysis for both lamps. The calculated rate constants confirmed the importance of •OH radicals for degradation of these compounds, especially for ibuprofen and gemfibrozil. For ibuprofen and gemfibrozil, direct photolysis rate constants could not be determined for LP-UV because very little degradation was seen at the fluences tested. LP-UV direct phototlysis rate constants for naproxen and triclosan were 0.0002 and 0.0033 cm²/mJ, respectively. Overall rate constants describing degradation of the four compounds due to LP-UV/H₂O₂ ranged from 0.0049 to 0.0124 cm²/mJ. All four compounds had fluence-based reaction rate constants for MP-UV indirect photolysis of approximately 0.01 cm²/mJ, while MP-UV direct photolysis rate constants ranged between 0.0007-0.007 cm²/mJ, with ibuprofen having the lowest and triclosan the highest.
The overall trends were similar to those seen by other researchers for the removal of taste and odour compounds. For example, fluences required for substantial removal were much higher than typical disinfection doses, the MP lamp was more effective than the LP lamp (when compared solely on a fluence-basis), and the addition of H₂O₂ improved removals.
On the whole, UV/H₂O₂ appears to be a very promising technology for the removal of these selected PPCPs during drinking water treatment, and is likely to be equally effective for other, similar contaminants.
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A Bench-scale Evaluation of the Removal of Selected Pharmaceuticals and Personal Care Products by UV and UV/H₂O₂ in Drinking Water TreatmentCrosina, Quinn Kathleen 12 1900 (has links)
A bench-scale study of the degradation of four selected pharmaceuticals and personal care products (PPCPs) was carried out using UV and UV/H₂O₂ treatment employing low pressure (LP) and medium pressure (MP) lamps. The target substances included the pharmaceutical compounds ibuprofen, naproxen, and gemfibrozil, along with the bactericide triclosan. There were four main objectives of the study, as follows: to evaluate the removal of the target compounds using UV irradiation alone and UV/H₂O₂, to determine the reaction kinetics for direct and indirect photolysis of each selected compound, to determine the influence of major water quality parameters on the efficacy of treatment, and to compare the applied UV and UV/H₂O₂ doses to those that have been found to be effective for disinfection and removal of taste and odour compounds, respectively.
For initial ultra-pure water experiments the target compounds were spiked at concentrations of approximately 250 µg/L (~1 µM). In latter ultra-pure water experiments and in the partially-treated water experiments, the selected PPCPs were spiked at a lower range (c~500-1000 ng/L), which is more representative of reported environmental concentrations. In an ultra-pure water matrix, a high LP fluence of 1000 mJ/cm² caused only triclosan to substantially degrade. Furthermore, with LP-UV/H₂O₂ only triclosan and naproxen had average percent removals above 60% at a typical disinfection fluence of 40 mJ/cm² with 100 mg/L H₂O₂. Complete degradation of all four compounds in ultra-pure water was achieved with very high fluences (compared to those used for UV disinfection) with MP-UV alone (at or above 1000 mJ/cm²) or with relatively high fluences for MP-UV/H₂O₂ (200-300 mJ/cm²) with 10 mg/L H₂O₂. Overall, when compared at similar applied fluences, the MP lamp was much more effective than the LP lamp. Furthermore, the addition of H₂O₂ typically increased removal rates, in some cases substantially, through formation and subsequent reaction of the PPCP with the •OH radical.
When target substances were treated all together in an ultra-pure water solution, removals were lower than when they were treated independently at the same individual concentrations (~250 µg/L) this may simply have been the result of a higher total contaminant concentration in solution, which lessened the availability of the •OH radical and incident UV irradiation for degradation of all compounds. On the other hand, removals were improved when the combined target compounds were present at a lower individual concentration range (~750 ng/L), which suggests that removals may be concentration driven, with reduced matrix effects seen at lower overall contaminant concentrations. Furthermore, during the partially-treated water experiments, variability in treatment performance was observed with differing water quality; however, it was not evident which specific quality parameters influenced treatment effectiveness. On the other hand, substantial and sometimes complete, degradation of the target compounds was still seen in the partially-treated water with high MP-UV/H₂O₂ doses (e.g. 300 mJ/cm² + 10 mg/L H₂O₂ and 500 + 10 mg/L H₂O₂).
For the kinetic experiments, compounds were spiked individually in ultra-pure water (c~250 µg/L = ~1µM). The photolysis of the target compounds during treatment was assumed to be a pseudo-first-order reaction. Kinetic parameters were determined for both direct and indirect photolysis for both lamps. The calculated rate constants confirmed the importance of •OH radicals for degradation of these compounds, especially for ibuprofen and gemfibrozil. For ibuprofen and gemfibrozil, direct photolysis rate constants could not be determined for LP-UV because very little degradation was seen at the fluences tested. LP-UV direct phototlysis rate constants for naproxen and triclosan were 0.0002 and 0.0033 cm²/mJ, respectively. Overall rate constants describing degradation of the four compounds due to LP-UV/H₂O₂ ranged from 0.0049 to 0.0124 cm²/mJ. All four compounds had fluence-based reaction rate constants for MP-UV indirect photolysis of approximately 0.01 cm²/mJ, while MP-UV direct photolysis rate constants ranged between 0.0007-0.007 cm²/mJ, with ibuprofen having the lowest and triclosan the highest.
The overall trends were similar to those seen by other researchers for the removal of taste and odour compounds. For example, fluences required for substantial removal were much higher than typical disinfection doses, the MP lamp was more effective than the LP lamp (when compared solely on a fluence-basis), and the addition of H₂O₂ improved removals.
On the whole, UV/H₂O₂ appears to be a very promising technology for the removal of these selected PPCPs during drinking water treatment, and is likely to be equally effective for other, similar contaminants.
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The occurrence of the pharmaceuticals and personal care products (PPCPs) and illicit drugs in western Hengchun Peninsula and Kenting tourist area of TaiwanTu, Bo-Wen 26 September 2012 (has links)
This study investigated the spatial distribution and seasonal variation of pharmaceuticals and personal care products (PPCPs) and illicit drugs in western Hengchun peninsula and Kenting coastal tourist area in Taiwan. We used solid phase extraction (SPE) followed by liquid-chromatography tandem mass spectrometry (HPLC-MS/MS) to determine 22 PPCPs and 10 illicit drugs in water samples. The detected concentrations of PPCPs and illicit drugs ranged from below detection limit to 9350 ng/L, and the most frequently five detected compounds in this area were ampicillin (79%), codeine (63%), caffeine (62%), carbamazepine (61%) and pseudoephedrine (57%). The impact of the special event- Kenting music festival, such as ¡§spring scream¡¨ was also discussed in this study, and the results from PCA and HCA both showed that the concentrations and distributions of PPCPs and illicit drugs were affected by the tourists. In addition, two wastewater treatments plants (WWTPs) were also investigated for seven days during Kenting music festival period. The results indicated that WWTPs did not show enough removal efficiencies in Kenting tourist area during the special event. The impact of the PPCPs and illicit drugs to the aquatic environment and ecology still needs to be further monitored.
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Membrane bioreactor treatment of household light greywater : measurement and effects of phosphorus limitationVan Epps, Amanda Jane 15 July 2013 (has links)
As water stresses increase across the U.S., interest in household water reuse is growing. Such reuse typically focuses on light greywater, that is all wastewater generated in the house excluding toilet waste and kitchen wastewater. As this practice becomes more widespread, higher level reuse is expected to require greater greywater treatment prior to reuse. Membrane bioreactors (MBRs) are an attractive technology for this application because they offer a robust combination of treatment processes and are already used in some households in countries such as Japan. This research sought to understand the role of phosphorus availability in determining the quality of effluent from MBR treatment of light greywater because phosphorus concentrations are expected to be low with phosphorus phased out of many consumer products. Less than 30 [mu]g/L of dissolved orthophosphate was present in synthetic greywater made from three common household products, and no measurable amount of dissolved orthophosphate was found in real greywater, but low concentrations of particulate phosphate were detected. These concentrations were well below levels believed necessary to achieve full BOD₅ removal in biological treatment. Nevertheless, MBR performance was not adversely affected until no supplemental phosphorus was provided. Measurement of extracellular enzyme activity showed an increase in the ratio of phosphatase activity to total glycosidase activity with declining phosphorus concentration, providing an early indication of nutrient stress before changes in effluent water quality were detected. Removal of three xenobiotic organic compounds (XOCs) in treatment of synthetic greywater was also evaluated under conditions of phosphorous limitation and balance. Abiotic removal mechanisms were not deemed to be important, but removal of methylparaben and sodium lauryl sulfate via biodegradation responded to nutrient limitation similarly to overall COD removal while removal of diethyl phthalate was affected to a greater extent. Measurement of plasmid DNA concentrations was evaluated as a potential indicator of the effect of nutrient limitation on plasmid-mediated biodegradation of XOCs. An overall reduction in the plasmid content was observed in all cases under conditions of phosphorus limitation; however, the extent of reduction was reactor dependent. / text
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