| 1. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 2. |
- Betsholtz, Alexander
(författare)
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Adsorption and transformation of organic micropollutants in wastewater : New insights from 14C-labeling
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis focuses on the removal of organic micropollutants and transformation products using ozone and activated carbon treatment processes. A combination of 14C-labeled and non-radiolabeled organic micropollutants was used to study aspects of micropollutant removal from novel perspectives. 14C-labeled ozone transformation products (OTPs) were generated by ozonation of 14C-labeled micropollutants and used to study the combined removal of OTPs via adsorption onto powdered activated carbon. A successive decrease in OTP adsorption was observed with increasing ozone doses, compared with adsorption of the parent compounds, suggesting that adsorption onto activated carbon alone is not viable for removing OTPs.14C-labeled micropollutants were also used to separate biological degradation (biodegradation) from adsorption in granular activated carbon (GAC) filters via the formation of 14CO2 from 14C-labeled moieties. It was shown that previously adsorbed diclofenac could be subsequently degraded, and the GAC biofilm demonstrated diclofenac biodegradation rates high enough for substantial diclofenac removal by GAC filters under typical operating conditions. The retention of micropollutants in GAC filters, by decoupling biological degradation time from hydraulic retention time, was then hypothesized to improve the conditions for biological degradation of certain micropollutants.Lastly, 14C-labeled micropollutants were used to examine the mineralization (14CO2 formation) of 14C-labeled moieties in organic micropollutants during ozonation. Based on 14CO2 formation, several transformation pathways were confirmed during ozonation, including the cleavage of aromatic rings in sulfamethoxazole, sulfadiazine, and bisphenol A and the decarboxylation of carboxylic groups in diclofenac and ibuprofen.
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| 3. |
- Betsholtz, Alexander, et al.
(författare)
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New Perspectives on the Interactions between Adsorption and Degradation of Organic Micropollutants in Granular Activated Carbon Filters
- 2024
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Ingår i: Environmental Science and Technology. - : American Chemical Society. - 0013-936X .- 1520-5851. ; 58:26
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Tidskriftsartikel (refereegranskat)abstract
- The removal of organic micropollutants in granular activated carbon (GAC) filters can be attributed to adsorption and biological degradation. These two processes can interact with each other or proceed independently. To illustrate the differences in their interaction, three 14C-labeled organic micropollutants with varying potentials for adsorption and biodegradation were selected to study their adsorption and biodegradation in columns with adsorbing (GAC) and non-adsorbing (sand) filter media. Using 14CO2 formation as a marker for biodegradation, we demonstrated that the biodegradation of poorly adsorbing N-nitrosodimethylamine (NDMA) was more sensitive to changes in the empty bed contact time (EBCT) compared with that of moderately adsorbing diclofenac. Further, diclofenac that had adsorbed under anoxic conditions could be degraded when molecular oxygen became available, and substantial biodegradation (≥60%) of diclofenac could be achieved with a 15 min EBCT in the GAC filter. These findings suggest that theretention of micropollutants in GAC filters, by prolonging the micropollutant residence time through adsorption, can enable longer time periods for degradations than what the hydraulic retention time would allow for. For the biologically recalcitrant compound carbamazepine, differences in breakthrough between the 14C-labeled and nonradiolabeled compounds revealed a substantial retention via successive adsorption-desorption, which could pose a potential challenge in the interpretation of GAC filter performance.
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| 4. |
- Betsholtz, Alexander, et al.
(författare)
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Ozonation of 14C-labeled micropollutants – mineralization of labeled moieties and adsorption of transformation products to activated carbon
- 2022
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 221
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Tidskriftsartikel (refereegranskat)abstract
- Ozonation transformation products (OTPs) are largely unknown compounds that are formed during the ozonation of micropollutants, and it is uncertain to which extent these compounds can be removed by subsequent adsorption to activated carbon. Thus, 14C-labeled micropollutants were ozonated to generate 14C-labeled OTPs, for which the adsorption of the sum of all 14C-labeled OTPs to activated carbon could be determined, based on the adsorption of the labeled carbon. Further, 14CO2 traps were used to examine the mineralization of 14C-labeled moieties during ozonation. 14CO2-formation revealed a partial mineralization of the 14C-labeled moieties in all compounds except for propyl-labeled bisphenol A and O-methyl-labeled naproxen. A similar degree of mineralization was noted for different compounds labeled at the same moiety, including the carboxylic carbon in diclofenac and ibuprofen (∼40% at 1 g O3/g DOC) and the aniline ring in sulfamethoxazole and sulfadiazine (∼30% at 1 g O3/g DOC). Aromatic ring cleavage was also confirmed for bisphenol A, sulfamethoxazole, and sulfadiazine through the formation of 14CO2. The adsorption experiments demonstrated increased adsorption of micropollutants to powdered activated carbon after ozonation, which was connected to a decreased adsorption of dissolved organic matter (DOM). Conversely, the OTPs showed a substantial and successive decline in adsorption at increased ozone doses for all compounds, likely due to decreased hydrophobicity and aromaticity of the OTPs. These findings indicate that adsorption to activated carbon alone is not a viable removal method for a wide range of ozonation transformation products.
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| 5. |
- Betsholtz, Alexander, et al.
(författare)
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Sewage sludge-based activated carbon – Production and potential in wastewater and stormwater treatment
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- SummarySustainable sewage sludge management has been a heavily debated topic in Europe for more than a decade. Due to its content of pollutants such as heavy metals, pharmaceuticals and other organic micropollutants, the use of sewage sludge for farmland application is currently banned or restricted in most European countries. Therefore, alternative methods for sludge management are discussed. The production of sludge-based activated carbon (SBAC) from digested sewage sludge is an alternative that would make use of problematic waste—sewage sludge—to produce a potentially valuable adsorbent. In this study, SBAC has been reviewed based on its potential use as an adsorbent for pollutants in wastewater and stormwater. The study consists of a literature review targeting (i) different methods for SBAC production, (ii) the influence of the production methods on the physical and chemical properties of the activated carbons and (iii) the importance of physical and chemical carbon properties on the adsorption of various types of pollutants in aquatic solutions. In connection to the literature study, SBAC was produced in the laboratory using a one-step steam activation method in order to study how various production parameters, such as pyrolysis temperature and steam oxidation, affect the porosity development of SBAC. The porosity of the carbon was assessed using N2adsorption and desorption isotherms at 77 K. Several combinations of the decisive parameters at various levels were tested and consequently the steam activated SBAC with highest volume of micropores (and highest specific surface area) was selected and tested for the adsorption of chemical oxygen demand (COD) and inorganic nutrients (NH4+, NO3-and PO43-) in wastewater from Källby WWTP in Lund, Sweden. As a reference, the SBAC was compared with a commercial activated carbon (CAC), Norit Sae Super (from Cabot), with a BET surface area of 975 m2/g. The results from existing literature show that SBAC, due to their high inorganic content, in general exhibit low micropore volumes compared to CAC, and therefore also tend to have a lower adsorption potential for small organic substances. However, the larger pores of the SBAC might be advantageous for adsorption of large organic pollutants such as dyes. In addition, the inorganic content of SBAC may contribute to the adsorption of charged and/or hydrophilic substances that are adsorbed through chemical interactions with surface functional groups of the carbon, rather than by physical adsorption to the core carbon structure. With respect to SBAC production, both feedstock type (e.g. biological sludge vs. chemical sludge) and production method (chemical vs. physical activation) have large influence on the properties of the carbon. In general, chemical activation using strong acids or based tend to generate SBAC with higher micropore volumes and abundance of surface functional groups compared to physical activation methods (such as steam activation), although its applicability can be questioned due to the large required input of chemicals. The result from the laboratory studies show that steam activated SBAC with BET surface areas of up to 162 m2/g could be generated using one-step steam activation at 800 °C for 30 minutes, although activation parameters were not optimized with respect to maximum surface area generation. The adsorption experiments showed that CAC was much better at adsorbing COD in effluent wastewater compared to the steam activated SBAC produced in lab, especially at low carbon concentrations. The experiments further showed that neither CAC nor SBAC was successful in adsorbing large quantities of inorganic nutrients (NH4+, NO3-and PO43-), probably due to lack of charged surface functional groups. Much work remains in order to demonstrate large scale production of SBAC in order to evaluate the economic feasibility of the process. In connection, more work is needed to understand how to maximize the potential of SBAC for the uptake of specific substances such as heavy metals or hydrophilic micropollutants.
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| 6. |
- Betsholtz, Alexander, et al.
(författare)
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Tracking 14C-labeled organic micropollutants to differentiate between adsorption and degradation in GAC and biofilm processes
- 2021
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Ingår i: Environmental Science and Technology. - : The American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:16, s. 11318-11327
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Tidskriftsartikel (refereegranskat)abstract
- Granular activated carbon (GAC) filters can be used to reduce emissions of organic micropollutants via municipal wastewater, but it is still uncertain to which extent biological degradation contributes to their removal in GAC filters. 14C-labeled organic micropollutants were therefore used to distinguish degradation from adsorption in a GAC-filter media with associated biofilm. The rates and extents of biological degradation and adsorption were investigated and compared with other biofilm systems, including a moving bed biofilm reactor (MBBR) and a sand filter, by monitoring 14C activities in the liquid and gas phases. The microbial cleavage of ibuprofen, naproxen, diclofenac, and mecoprop was confirmed for all biofilms, based on the formation of 14CO2, whereas the degradation of 14C-labeled moieties of sulfamethoxazole and carbamazepine was undetected. Higher degradation rates for diclofenac were observed for the GAC-filter media than for the other biofilms. Degradation of previously adsorbed diclofenac onto GAC could be confirmed by the anaerobic adsorption and subsequent aerobic degradation by the GAC-bound biofilm. This study demonstrates the potential use of 14C-labeled micropollutants to study interactions and determine the relative contributions of adsorption and degradation in GAC-based treatment systems.
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| 7. |
- Betsholtz, Alexander, et al.
(författare)
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Tracking 14C-Labeled Organic Micropollutants to Differentiate between Adsorption and Degradation in GAC and Biofilm Processes
- 2021
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:16, s. 11318-11327
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Tidskriftsartikel (refereegranskat)abstract
- Granular activated carbon (GAC) filters can be used to reduce emissions of organic micropollutants via municipal wastewater, but it is still uncertain to which extent biological degradation contributes to their removal in GAC filters. 14C-labeled organic micropollutants were therefore used to distinguish degradation from adsorption in a GAC-filter media with associated biofilm. The rates and extents of biological degradation and adsorption were investigated and compared with other biofilm systems, including a moving bed biofilm reactor (MBBR) and a sand filter, by monitoring 14C activities in the liquid and gas phases. The microbial cleavage of ibuprofen, naproxen, diclofenac, and mecoprop was confirmed for all biofilms, based on the formation of 14CO2, whereas the degradation of 14C-labeled moieties of sulfamethoxazole and carbamazepine was undetected. Higher degradation rates for diclofenac were observed for the GAC-filter media than for the other biofilms. Degradation of previously adsorbed diclofenac onto GAC could be confirmed by the anaerobic adsorption and subsequent aerobic degradation by the GAC-bound biofilm. This study demonstrates the potential use of 14C-labeled micropollutants to study interactions and determine the relative contributions of adsorption and degradation in GAC-based treatment systems.
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| 8. |
- ElBeck, Zaher, et al.
(författare)
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Epigenetic modulators link mitochondrial redox homeostasis to cardiac function in a sex-dependent manner
- 2024
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- While excessive production of reactive oxygen species (ROS) is a characteristic hallmark of numerous diseases, clinical approaches that ameliorate oxidative stress have been unsuccessful. Here, utilizing multi-omics, we demonstrate that in cardiomyocytes, mitochondrial isocitrate dehydrogenase (IDH2) constitutes a major antioxidative defense mechanism. Paradoxically reduced expression of IDH2 associated with ventricular eccentric hypertrophy is counterbalanced by an increase in the enzyme activity. We unveil redox-dependent sex dimorphism, and extensive mutual regulation of the antioxidative activities of IDH2 and NRF2 by a feedforward network that involves 2-oxoglutarate and L-2-hydroxyglutarate and mediated in part through unconventional hydroxy-methylation of cytosine residues present in introns. Consequently, conditional targeting of ROS in a murine model of heart failure improves cardiac function in sex- and phenotype-dependent manners. Together, these insights may explain why previous attempts to treat heart failure with antioxidants have been unsuccessful and open new approaches to personalizing and, thereby, improving such treatment.
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| 9. |
- Gidstedt, Simon, et al.
(författare)
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A comparison of adsorption of organic micropollutants onto activated carbon following chemically enhanced primary treatment with microsieving, direct membrane filtration and tertiary treatment of municipal wastewater
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 811:152225
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption of organic micropollutants onto powdered activated carbon (PAC) was investigated in laboratory scale based on samples from four wastewater process streams (matrices); three from a pilot-scale plant with different degrees of physicochemical treatment of municipal wastewater and one from a full-scale activated sludge plant with post-precipitation. The pilot-scale treatment consisted of chemically enhanced primary treatment with microsieving followed by direct membrane filtration as microfiltration or ultrafiltration. The results showed highest adsorption of micropollutants in the tertiary (biologically and chemically) treated wastewater and lowest adsorption in the microsieve filtrate. Adsorption of micropollutants in the direct membrane microfiltration (200 nm) permeate was generally similar to that in the direct membrane ultrafiltration (3 nm) permeate. The higher adsorption of micropollutants in the tertiary treated wastewater could be related to a lower concentration of dissolved organic carbon (DOC) and lower affinity of DOC for PAC at low dosage (<15 mg PAC/L) in this matrix. At a PAC dose of 10 mg/L, sulfamethoxazole was removed by 33% in the tertiary treated wastewater and 7% in the direct membrane microfiltration permeate. In addition to the PAC experiments, a pilot scale sand filter and a proceeding GAC filter was operated on tertiary treated wastewater from the full-scale treatment plant. Similar removal trends in the PAC and GAC experiments were observed when studying a weighted average micropollutant removal in the GAC filter and a similar dose of activated carbon for both PAC and GAC. Positively charged micropollutants were removed to a higher extent than negatively charged ones by both PAC and GAC.
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| 10. |
- Gidstedt, Simon, et al.
(författare)
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Chemically enhanced primary treatment, microsieving, direct membrane filtration and GAC filtration of municipal wastewater : a pilot-scale study
- 2022
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Ingår i: Environmental Technology (United Kingdom). - : Taylor and Francis Ltd.. - 0959-3330 .- 1479-487X. ; , s. 12
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Tidskriftsartikel (refereegranskat)abstract
- Chemically enhanced primary treatment (CEPT) followed by microsieving and direct membrane filtration (DMF) as ultrafiltration, was evaluated on pilot scale at a municipal wastewater treatment plant. In addition, a granular activated carbon (GAC) filter downstream of DMF was evaluated for the removal of organic micropollutants. Up to 80% of the total organic carbon (TOC) and 96% of the total phosphorus were removed by CEPT with microsieving. The additional contribution of subsequent DMF was minor, and only five days of downstream GAC filtration was possible due to fouling of the membrane. Of the 21 organic micropollutants analysed, all were removed (≥ 98%) by the GAC filter until 440 bed volumes, while CEPT with microsieving and DMF removed only a few compounds. Measurements of the oxygen uptake rate indicated that the required aeration for supplementary biological treatment downstream of CEPT with microsieving, both with and without subsequent DMF, was 20−25% of that in the influent wastewater. This study demonstrated the potential of using compact physicochemical processes to treat municipal wastewater, including the removal of organic micropollutants.
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| 11. |
- Pang, M-F, et al.
(författare)
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TGF-beta 1-induced EMT promotes targeted migration of breast cancer cells through the lymphatic system by the activation of CCR7/CCL21-mediated chemotaxis
- 2016
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Ingår i: Oncogene. - : Nature Publishing Group. - 0950-9232 .- 1476-5594. ; 35:6, s. 748-760
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Tidskriftsartikel (refereegranskat)abstract
- Tumor cells frequently disseminate through the lymphatic system during metastatic spread of breast cancer and many other types of cancer. Yet it is not clear how tumor cells make their way into the lymphatic system and how they choose between lymphatic and blood vessels for migration. Here we report that mammary tumor cells undergoing epithelial-mesenchymal transition (EMT) in response to transforming growth factor-beta (TGF-beta 1) become activated for targeted migration through the lymphatic system, similar to dendritic cells (DCs) during inflammation. EMT cells preferentially migrated toward lymphatic vessels compared with blood vessels, both in vivo and in 3D cultures. A mechanism of this targeted migration was traced to the capacity of TGF-beta 1 to promote CCR7/CCL21-mediated crosstalk between tumor cells and lymphatic endothelial cells. On one hand, TGF-beta 1 promoted CCR7 expression in EMT cells through p38 MAP kinase-mediated activation of the JunB transcription factor. Blockade of CCR7, or treatment with a p38 MAP kinase inhibitor, reduced lymphatic dissemination of EMT cells in syngeneic mice. On the other hand, TGF-beta 1 promoted CCL21 expression in lymphatic endothelial cells. CCL21 acted in a paracrine fashion to mediate chemotactic migration of EMT cells toward lymphatic endothelial cells. The results identify TGF-beta 1-induced EMT as a mechanism, which activates tumor cells for targeted, DC-like migration through the lymphatic system. Furthermore, it suggests that p38 MAP kinase inhibition may be a useful strategy to inhibit EMT and lymphogenic spread of tumor cells.
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| 12. |
- Pietilä, Riikka, et al.
(författare)
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Molecular anatomy of adult mouse leptomeninges
- 2023
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Ingår i: Neuron. - : Elsevier. - 0896-6273 .- 1097-4199. ; 111:23
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Tidskriftsartikel (refereegranskat)abstract
- Leptomeninges, consisting of the pia mater and arachnoid, form a connective tissue investment and barrier enclosure of the brain. The exact nature of leptomeningeal cells has long been debated. In this study, we iden-tify five molecularly distinct fibroblast-like transcriptomes in cerebral leptomeninges; link them to anatomically distinct cell types of the pia, inner arachnoid, outer arachnoid barrier, and dural border layer; and contrast them to a sixth fibroblast-like transcriptome present in the choroid plexus and median eminence. Newly identified transcriptional markers enabled molecular characterization of cell types responsible for adherence of arach-noid layers to one another and for the arachnoid barrier. These markers also proved useful in identifying the molecular features of leptomeningeal development, injury, and repair that were preserved or changed after traumatic brain injury. Together, the findings highlight the value of identifying fibroblast transcriptional subsets and their cellular locations toward advancing the understanding of leptomeningeal physiology and pathology.
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| 13. |
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| 14. |
- Takman, Maria, et al.
(författare)
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Biological degradation of organic micropollutants in GAC filters–temporal development and spatial variations
- 2024
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Ingår i: Journal of Hazardous Materials. - : Elsevier. - 0304-3894. ; 472
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Tidskriftsartikel (refereegranskat)abstract
- The capacity for organic micropollutant removal in granular activated carbon (GAC) filters for wastewater treatment changes over time. These changes are in general attributed to changes in adsorption, but may in some cases also be affected by biological degradation. Knowledge on the degradation of organic micropollutants, however, is scarce. In this work, the degradation of micropollutants in several full-scale GAC and sand filters was investigated through incubation experiments over a period of three years, using 14C-labeled organic micropollutants with different susceptibilities to biological degradation (ibuprofen, diclofenac, and carbamazepine), with parallel 16S rRNA gene sequencing. The results showed that the degradation of diclofenac and ibuprofen in GAC filters increased with increasing numbers of bed volumes when free oxygen was available in the filter, while variations over filter depth were limited. Despite relatively large differences in bacterial composition between filters, a degradation of diclofenac was consistently observed for the GAC filters that had been operated with high influent oxygen concentration (DO >8 mg/L). The results of this comprehensive experimental work provide an increased understanding of the interactions between microbial composition, filter material, and oxygen availability in the biological degradation of organic micropollutants in GAC filters.
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