| 1. |
- Antoniou, Maria G., et al.
(author)
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Required ozone doses for removing pharmaceuticals from wastewater effluents
- 2013
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In: Science of the Total Environment. - Amsterdam : Elsevier BV. - 1879-1026 .- 0048-9697. ; 456, s. 42-49
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Journal article (peer-reviewed)abstract
- The aim of the this study was to investigate the ozone dosage required to remove active pharmaceutical ingredients (APIs) from biologically treated wastewater of varying quality, originated from different raw wastewater and wastewater treatment processes. Secondary effluents from six Swedish wastewater treatment plants (WWTP) were spiked with 42 APIs (nominal concentration 1 mu g/L) and treated with different O-3 doses (0.5-12.0 mg/L ozone) in bench-scale experiments. In order to compare the sensitivity of APIs in each matrix, the specific dose of ozone required to achieve reduction by one decade of each investigated API (DDO3) was determined for each effluent by fitting a first order equation to the remaining concentration of API at each applied ozone dose. Ozone dose requirements were found to vary significantly between effluents depending on their matrix characteristics. The specific ozone dose was then normalized to the dissolved organic carbon (DOC) of each effluent. The DDO3/DOC ratios were comparable for each API between the effluents. 15 of the 42 investigated APIs could be classified as easily degradable (DDO3/DOC <= 0.7), while 19 were moderately degradable (0.7 < DDO3/DOC <= 1.4), and 8 were recalcitrant towards O-3-treatment (DDO3/DOC > 1.4). Furthermore, we predict that a reasonable estimate of the ozone dose required to remove any of the investigated APIs may be attained by multiplying the experimental average DDO3/DOC obtained with the actual DOC of any effluent. (C) 2013 Elsevier B.V. All rights reserved.
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| 2. |
- Antoniou, Maria G., et al.
(author)
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Variability in required ozone doses for removing pharmaceuticals from wastewater effluents
- 2013
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In: Proceedings of the 13th International Conference on Environmental Science and Technology. - : Global Nest, Secretariat. - 9789607475510
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Conference paper (peer-reviewed)abstract
- Aim of study. The aim of the present study was to investigate the ozone dosage required to remove active pharmaceutical ingredients (APIs) from biologically treated wastewater of varying quality originating from different wastewater treatment processes. Methods. Secondary effluents from six Swedish wastewater treatment plants (VWVTP) were spiked with 42 APIs (nominal concentration 1pg/L) and treated with different 03 doses (0.5-12.0 mg/L ozone) in bench-scale experiments (Antoniou et al, 2012). Concentrations of APIs were measured by SPE extraction using OASIS HLB cartridges followed by quantification using LC-MS-MS (Grabic et al, 2012).. Results. For each wastewater effluent a profile of sensitivity of each API to a range of ozone doses were generated as shown in Figure 1.
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| 3. |
- Haghighatafshar, Salar, et al.
(author)
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Microsieving coupled with O3 or ClO2 for treatment and disinfection of combined sewer overflows
- 2018
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In: Vatten: tidskrift för vattenvård /Journal of Water Management and research. - 0042-2886. ; 74:3, s. 123-134
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Journal article (peer-reviewed)abstract
- A compact combined sewer overflow (CSO) treatment unit is set up and evaluated in pilot-scale. The pilotplant consisted of flocculation, coagulation and a microsieving system followed by a disinfection unit with either O3 or ClO2. Efficiency of the pilot-plant was evaluated with respect to reduction of Escherichia coli, coliform bacteria and intestinal enterococci as well as removal of biocides. Results showed that 10 mg L-1 of ClO2 as disinfectant was sufficient to meet the European Union (EU) requirements as per Bathing Water Directive (2006/7 EC) while the same results were only achieved when higher O3 dose (20 mg O3 L-1) was applied. This study revealed that chlorine dioxide was the most effective disinfectant agent in reducing the number of bacteria to below the limits set by the EU Bathing Water Directive and that the pre-treatment used was highly efficient. Regarding biocides, the efficiency of the removal was highly dependent on the type of substance. However, ozone was found to be able to remove a broader range of the investigated biocides.
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| 4. |
- Hey, Gerly
(author)
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Application of chemical oxidation processes for the removal of pharmaceuticals in biologically treated wastewater
- 2013
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Doctoral thesis (other academic/artistic)abstract
- The discharge of effluents from wastewater treatment plants (WWTPs) is considered to be the major source of residual pharmaceuticals frequently found in aquatic environments. The complex nature of such compounds tends to make conventional biological treatments aimed at their removal ineffective. The present thesis concerns the removal of 62 different active pharmaceutical ingredients commonly detected in Swedish wastewater effluents by means of chemical oxidation techniques. Techniques with potential to be effective are in particular peracetic acid (PAA), chlorine dioxide (ClO2), ozone (O3) and a combination of ozone and hydrogen peroxide (O3/H2O2), which all were included in this study. The performance of a given treatment was evaluated in terms of the degree of pharmaceutical removal achieved and the oxidant demand of the wastewater. The effects of the characteristics of the wastewater have on the degree of removal efficiency of different pharmaceuticals were also evaluated. Ozone is considered to be the most efficient chemical oxidant for reducing the concentrations of a large number of different pharmaceuticals, the ozone dose required for this being fairly low (5-10 mg/L), depending upon the characteristics of the effluent. Over 90% of the pharmaceuticals investigated in most of the effluents could be eliminated to 90-100% by use of ozone, while several of the pharmaceuticals being observed to be recalcitrant to chlorine dioxide treatment. The addition of small amounts of hydrogen peroxide during wastewater ozonation, although not enhancing the removal of pharmaceuticals, was found to increase ozone decomposition, presumably resulting in the formation of hydroxyl (OH) radicals as secondary oxidants. The addition of small amounts of H2O2 in this way is seen as being advantageous in terms of its reducing both the treatment time and the reaction tank volume which is needed. Of the various water quality parameters investigated, the organic carbon content was found to have a particularly strong effect on the removal of pharmaceuticals, due to its competitive behavior towards the oxidant. PAA appears to have the lowest degree of pharmaceutical removal, making it not a suitable treatment option for removing pharmaceuticals in the effluents. Although chlorine dioxide and ozone appeared quite similar in their manner of removing pharmaceuticals, both of them reacting with electron-rich functional groups such as those of the phenolic and amino type, some of the pharmaceuticals reacted more slowly with chlorine dioxide than with ozone, given the same reactive substituent and structural similarities. Thus, a decision regarding the possible use of chlorine dioxide for tertiary treatment should take account of how strongly the pollutant or pollutants in question are affected by it. The use of chlorine dioxide appeared to be particularly beneficial when a small-scale WWTP is involved or when treatment is required for only a limited period of time. Although ClO2 is slightly more expensive to produce than ozone, the preparation system and the reaction chamber for treatment that are required are far simpler and less expensive to build than those needed for ozone treatment. It was noted that energy costs connected with ozonation are a function both of the ozone demand of the wastewater and the contaminant or contaminants to be removed. It appeared that, in view of the high degree of reactivity of ozone to a broad range of the pharmaceuticals that were investigated, ozonation of secondary effluent is the most suitable alternative for most WWTPs.
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| 5. |
- Hey, Gerly, et al.
(author)
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Biodegradability and toxicity assessment of trans-chlordane photochemical treatment.
- 2008
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In: Chemosphere. - : Elsevier BV. - 1879-1298 .- 0045-6535. ; 73:9, s. 1512-1517
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Journal article (peer-reviewed)abstract
- The removal of trans-chlordane (C(10)H(6)Cl(8)) from aqueous solutions was studied using UV, UV/H(2)O(2), UV/H(2)O(2)/Fe(2+), UV/TiO(2), or UV/TiO(2)/H(2)O(2) treatment using either UV/Vis blue lamps or UVC lamps (254nm). H(2)O(2), FeSO(4) and TiO(2) were added at 1700, 456, and 2500mgL(-1), respectively. trans-Chlordane was not significantly removed in non-irradiated controls and in samples irradiated with UV/Vis. It was also not removed in the absence of surfactant Triton X-114 added at 250mgL(-1). In the presence of the surfactant, trans-chlordane concentration was reduced by 95-100% after 48h of UVC and UVC/H(2)O(2) treatments and 70-80% after UVC/H(2)O(2)/Fe(2+), UVC/TiO(2) and UVC/H(2)O(2)/TiO(2) treatments. Based on these results, UVC, UVC/H(2)O(2) and UVC/TiO(2) treatments were further investigated. UVC treatment supported the highest pollutant removal (100% in 48h), dechlorination efficiency (81% in 48h), and detoxification to Lepidium sativum seed germination and activated sludge respiration although irradiated samples remained toxic to Chlorella vulgaris. Biodegradation of the UVC irradiated samples removed the source of algae toxicity but this could not be clearly attributed to the removal of trans-chlordane photoproducts because the surfactant interfered with the chemical and biological assays. Evidence was found that trans-chlordane was photodegraded through photolysis causing its successive dechlorination. trans-Chlordane removal was well described by a first order kinetic model at a rate of 0.21+/-0.01h(-1) at the 95% confidence interval.
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| 6. |
- Hey, Gerly, et al.
(author)
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Oxidation of pharmaceuticals by chlorine dioxide in biologically treated wastewater
- 2012
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In: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 185, s. 236-242
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Journal article (peer-reviewed)abstract
- Biologically treated wastewater spiked with a mixture of 56 active pharmaceutical ingredients (APIs) was treated with 0-20 mg/L chlorine dioxide (ClO2) solution in laboratory-scale experiments. Wastewater effluents were collected from two wastewater treatment plants in Sweden, one with extended nitrogen removal (low COD) and one without (high COD). About one third of the tested APIs resisted degradation even at the highest ClO2 dose (20 mg/L), while others were reduced by more than 90% at the lowest ClO2 level (0.5 mg/L). In the low COD effluent, more than half of the APIs were oxidized at 5 mg/L ClO2, while in high COD effluent a significant increase in API oxidation was observed after treatment with 8 mg/L ClO2. This study illustrates the successful degradation of several APIs during treatment of wastewater effluents with chlorine dioxide.
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| 7. |
- Hey, Gerly, et al.
(author)
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Removal of pharmaceuticals in biologically treated wastewater by chlorine dioxide or peracetic acid
- 2012
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In: Environmental Technology. - : Informa UK Limited. - 1479-487X .- 0959-3330. ; 33:9, s. 1041-1047
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Journal article (peer-reviewed)abstract
- Removal of six active pharmaceutical ingredients in wastewater was investigated using chlorine dioxide (ClO2) or peracetic acid (PAA) as chemical oxidants. Four non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, diclofenac and mefenamic acid) and two lipid-regulating agents (gemfibrozil and clofibric acid, a metabolite of clofibrate) were used as target substances at 40 mu g/L initial concentration. Three different wastewaters types originating from two wastewater treatment plants (WWTPs) were used. One wastewater was collected after extended nitrogen removal in activated sludge, one after treatment with high-loaded activated sludge without nitrification, and one from the final effluent from the same plant where nitrogen removal was made in trickling filters for nitrification and moving-bed biofilm reactors for denitrification following the high-loaded plant. Of the six investigated compounds, only clofibric acid and ibuprofen were not removed when treated with ClO2 up to 20 mg/L. With increasing PAA dose up to 50 mg/L, significant removal of most of the pharmaceuticals was observed except for the wastewater with the highest chemical oxygen demand (COD). This indicates that chemical oxidation with ClO2 could be used for tertiary treatment at WWTPs for active pharmaceutical ingredients, whereas PAA was not sufficiently efficient.
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| 8. |
- Hey, Gerly, et al.
(author)
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Removal of pharmaceuticals in WWTP effluents by ozone and hydrogen peroxide
- 2014
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In: Water S.A.. - : Academy of Science of South Africa. - 1816-7950 .- 0378-4738. ; 40:1, s. 165-173
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Journal article (peer-reviewed)abstract
- Ozonation to achieve removal of pharmaceuticals from wastewater effluents, with pH values in the upper and lower regions of the typical range for Swedish wastewater, was investigated. The main aim was to study the effects of varying pH values (6.0 and 8.0), and if small additions of H2O2 prior to ozone treatment could improve the removal and lower the reaction time. The effluents studied differed in their chemical characteristics, particularly in terms of alkalinity (65.3-427 mg center dot l(-1) HCO3-), COD (18.2-41.8 mg center dot l(-1)), DOC (6.9-12.5 mg center dot l(-1)), ammonium content (0.02-3.6 mg center dot l(-1)) and specific UV absorbance (1.78-2.76 l center dot mg(-1)center dot m(-1)). As expected, lower ozone decomposition rates were observed in the effluents at pH 6.0 compared to pH 8.0. When pH 8.0 effluents were ozonated, a higher degree of pharmaceutical removal occurred in the effluent with low specific UV absorbance. For pH 6.0 effluents, the removal of pharmaceuticals was most efficient in the effluent with the lowest organic content. The addition of H2O2 had no significant effect on the quantitative removal of pharmaceuticals but enhanced the ozone decomposition rate. Thus, H2O2 addition increased the reaction rate. In practice, this will mean that the reactor volume needed for the ozonation of wastewater effluents can be reduced.
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