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Fens T, Moermond CTA, van der Maas P, Dantuma-Wering C, Lestestuiver GH, Szperl A, Schuiling LCM, Hak E, Taxis K. Reducing Pharmaceuticals in Water, a New Module Integrated in the Pharmacy Game: Evaluating the Module's Effects on Students' Knowledge and Attitudes. Pharmacy (Basel) 2024; 12:28. [PMID: 38392935 PMCID: PMC10892046 DOI: 10.3390/pharmacy12010028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/30/2024] [Accepted: 02/04/2024] [Indexed: 02/25/2024] Open
Abstract
Pharmaceutical residues end up in surface waters, impacting drinking water sources and contaminating the aquatic ecosystem. Pharmacists can play a role in reducing pharmaceutical residues, yet this is often not addressed in pharmacy undergraduate education. Therefore, we developed the educational module "Reducing Pharmaceuticals in Water" for pharmacy students; this was integrated in our pharmacy simulation game for third year Master of Pharmacy students at the University of Groningen. In this study, we aim to evaluate the effects of the module on students' knowledge of pharmaceutical residues in water, to describe students' experiences in taking the module, and to explore their attitudes towards green pharmacy education in general. This mixed-methods study included quantitative measurements, before and after students took the module (intervention group) and in a control group which did not receive the module. Data were collected between February 2023 and June 2023. Overall, 29 students took the module and 36 students were in the control group. The knowledge score of students in the intervention group (N = 29) increased significantly from 9.3 to 12.9 out of 22 (p < 0.001). The knowledge score of the students in the control group was (8.9 out of 22). Students found the e-learning and the patient cases the most exciting part of this module. Students also recognized the need to including environmental issues in pharmacy education. In conclusion, the module contributes towards improved knowledge and increased awareness of the impact of pharmaceuticals found in water. It represents a promising strategy to strengthen pharmacist's role in mitigating the amount and the effect of pharmaceuticals on water and the environment in the future.
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Affiliation(s)
- Tanja Fens
- Unit of PharmacoTherapy, -Epidemiology and -Economics, Groningen Research Institute of Pharmacy and School of Science and Engineering, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands (E.H.); (K.T.)
| | - Caroline T. A. Moermond
- Center for Safety of Substances and Products, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands;
| | - Peter van der Maas
- Research Group Sustainable Water Systems, Van Hall Larenstein, University of Applied Sciences, Agora 1, 8901 BV Leeuwarden, The Netherlands
| | - Claudia Dantuma-Wering
- Unit of PharmacoTherapy, -Epidemiology and -Economics, Groningen Research Institute of Pharmacy and School of Science and Engineering, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands (E.H.); (K.T.)
| | - Geke H. Lestestuiver
- Unit of Safety and Environment, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Agata Szperl
- Centre for Learning and Teaching (CLT), School of Science and Engineering, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands;
| | - Lisette C. M. Schuiling
- Behavioural and Social Sciences, University of Groningen, Grote Kruisstraat 2/1, 9712 TS Groningen, The Netherlands
| | - Eelko Hak
- Unit of PharmacoTherapy, -Epidemiology and -Economics, Groningen Research Institute of Pharmacy and School of Science and Engineering, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands (E.H.); (K.T.)
| | - Katja Taxis
- Unit of PharmacoTherapy, -Epidemiology and -Economics, Groningen Research Institute of Pharmacy and School of Science and Engineering, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands (E.H.); (K.T.)
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Pallares-Vega R, Macedo G, Brouwer MSM, Hernandez Leal L, van der Maas P, van Loosdrecht MCM, Weissbrodt DG, Heederik D, Mevius D, Schmitt H. Temperature and Nutrient Limitations Decrease Transfer of Conjugative IncP-1 Plasmid pKJK5 to Wild Escherichia coli Strains. Front Microbiol 2021; 12:656250. [PMID: 34349732 PMCID: PMC8326584 DOI: 10.3389/fmicb.2021.656250] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 06/23/2021] [Indexed: 11/13/2022] Open
Abstract
Plasmid-mediated dissemination of antibiotic resistance among fecal Enterobacteriaceae in natural ecosystems may contribute to the persistence of antibiotic resistance genes in anthropogenically impacted environments. Plasmid transfer frequencies measured under laboratory conditions might lead to overestimation of plasmid transfer potential in natural ecosystems. This study assessed differences in the conjugative transfer of an IncP-1 (pKJK5) plasmid to three natural Escherichia coli strains carrying extended-spectrum beta-lactamases, by filter mating. Matings were performed under optimal laboratory conditions (rich LB medium and 37°C) and environmentally relevant temperatures (25, 15 and 9°C) or nutrient regimes mimicking environmental conditions and limitations (synthetic wastewater and soil extract). Under optimal nutrient conditions and temperature, two recipients yielded high transfer frequencies (5 × 10-1) while the conjugation frequency of the third strain was 1000-fold lower. Decreasing mating temperatures to psychrophilic ranges led to lower transfer frequencies, albeit all three strains conjugated under all the tested temperatures. Low nutritive media caused significant decreases in transconjugants (-3 logs for synthetic wastewater; -6 logs for soil extract), where only one of the strains was able to produce detectable transconjugants. Collectively, this study highlights that despite less-than-optimal conditions, fecal organisms may transfer plasmids in the environment, but the transfer of pKJK5 between microorganisms is limited mainly by low nutrient conditions.
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Affiliation(s)
- Rebeca Pallares-Vega
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, Netherlands
- Department Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Gonçalo Macedo
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, Netherlands
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Michael S. M. Brouwer
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, Netherlands
| | - Lucia Hernandez Leal
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, Netherlands
| | - Peter van der Maas
- Van Hall Larenstein, University of Applied Sciences, Leeuwarden, Netherlands
| | | | - David G. Weissbrodt
- Department Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Dick Heederik
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, Netherlands
| | - Dik Mevius
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, Netherlands
| | - Heike Schmitt
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, Netherlands
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, Netherlands
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Macedo G, van Veelen HPJ, Hernandez-Leal L, van der Maas P, Heederik D, Mevius D, Bossers A, Schmitt H. Targeted metagenomics reveals inferior resilience of farm soil resistome compared to soil microbiome after manure application. Sci Total Environ 2021; 770:145399. [PMID: 33736375 DOI: 10.1016/j.scitotenv.2021.145399] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 05/26/2023]
Abstract
Application of animal manure to soils results in the introduction of manure-derived bacteria and their antimicrobial resistance genes (ARGs) into soils. ResCap is a novel targeted-metagenomic approach that allows the detection of minority components of the resistome gene pool without the cost-prohibitive coverage depths and can provide a valuable tool to study the spread of antimicrobial resistance (AMR) in the environment. We used high-throughput sequencing and qPCR for 16S rRNA gene fragments as well as ResCap to explore the dynamics of bacteria, and ARGs introduced to soils and adjacent water ditches, both at community and individual scale, over a period of three weeks. The soil bacteriome and resistome showed strong resilience to the input of manure, as manuring did not impact the overall structure of the bacteriome, and its effects on the resistome were transient. Initially, manure application resulted in a substantial increase of ARGs in soils and adjacent waters, while not affecting the overall bacterial community composition. Still, specific families increased after manure application, either through the input of manure (e.g., Dysgonomonadaceae) or through enrichment after manuring (e.g., Pseudomonadaceae). Depending on the type of ARG, manure application resulted mostly in an increase (e.g., aph(6)-Id), but occasionally also in a decrease (e.g., dfrB3) of the absolute abundance of ARG clusters (FPKM/kg or L). This study shows that the structures of the bacteriome and resistome are shaped by different factors, where the bacterial community composition could not explain the changes in ARG diversity or abundances. Also, it highlights the potential of applying targeted metagenomic techniques, such as ResCap, to study the fate of AMR in the environment.
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Affiliation(s)
- Gonçalo Macedo
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, the Netherlands.
| | - H Pieter J van Veelen
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, the Netherlands
| | - Lucia Hernandez-Leal
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, the Netherlands
| | - Peter van der Maas
- Van Hall Larenstein, University of Applied Sciences, Agora 1, 8901 BV Leeuwarden, the Netherlands
| | - Dick Heederik
- Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3584, CM, Utrecht, the Netherlands
| | - Dik Mevius
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands; Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Houtribweg 39, 8221 RA Lelystad, the Netherlands
| | - Alex Bossers
- Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3584, CM, Utrecht, the Netherlands; Department of Infection Biology, Wageningen Bioveterinary Research, Houtribweg 39, 8221 RA Lelystad, the Netherlands
| | - Heike Schmitt
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, the Netherlands
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Macedo G, Hernandez-Leal L, van der Maas P, Heederik D, Mevius D, Schmitt H. The impact of manure and soil texture on antimicrobial resistance gene levels in farmlands and adjacent ditches. Sci Total Environ 2020; 737:139563. [PMID: 32512295 DOI: 10.1016/j.scitotenv.2020.139563] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 05/26/2023]
Abstract
Manure application can spread antimicrobial resistance (AMR) from manure to soil and surface water. This study evaluated the role of the soil texture on the dynamics of antimicrobial resistance genes (ARGs) in soils and surrounding surface waters. Six dairy farms with distinct soil textures (clay, sand, and peat) were sampled at different time points after the application of manure, and three representative ARGs sul1, erm(B), and tet(W) were quantified with qPCR. Manuring initially increased levels of erm(B) by 1.5 ± 0.5 log copies/kg of soil and tet(W) by 0.8 ± 0.4 log copies/kg across soil textures, after which levels gradually declined. In surface waters from clay environments, regardless of the ARG, the gene levels initially increased by 2.6 ± 1.6 log copies/L, after which levels gradually declined. The gene decay in soils was strongly dependent on the type of ARG (erm(B) < tet(W) < sul1; half-lives of 7, 11, and 75 days, respectively), while in water, the decay was primarily dependent on the soil texture adjacent to the sampled surface water (clay < peat < sand; half-lives of 2, 6, and 10 days, respectively). Finally, recovery of ARG levels was predicted after 29-42 days. The results thus showed that there was not a complete restoration of ARGs in soils between rounds of manure application. In conclusion, this study demonstrates that rather than showing similar dynamics of decay, factors such as the type of ARG and soil texture drive the ARG persistence in the environment.
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Affiliation(s)
- Gonçalo Macedo
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, the Netherlands; Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands.
| | - Lucia Hernandez-Leal
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, the Netherlands
| | - Peter van der Maas
- Van Hall Larenstein, University of Applied Sciences, Agora 1, 8901 BV Leeuwarden, the Netherlands
| | - Dick Heederik
- Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3584 CM Utrecht, the Netherlands
| | - Dik Mevius
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands; Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Houtribweg 39, 8221 RA Lelystad, the Netherlands
| | - Heike Schmitt
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, the Netherlands; Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands; Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3584 CM Utrecht, the Netherlands
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Maas PVD, Brink PVD, Klapwijk B, Lens P. Acceleration of the Fe(III)EDTA(-) reduction rate in BioDeNO(x) reactors by dosing electron mediating compounds. Chemosphere 2009; 75:243-249. [PMID: 18561978 DOI: 10.1016/j.chemosphere.2008.04.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 04/14/2008] [Accepted: 04/15/2008] [Indexed: 05/26/2023]
Abstract
BioDeNO(x), a novel technique to remove NO(x) from industrial flue gases, is based on absorption of gaseous nitric oxide into an aqueous Fe(II)EDTA(2-) solution, followed by the biological reduction of Fe(II)EDTA(2-) complexed NO to N(2). Besides NO reduction, high rate biological Fe(III)EDTA(-) reduction is a crucial factor for a succesful application of the BioDeNO(x) technology, as it determines the Fe(II)EDTA(2-) concentration in the scrubber liquor and thus the efficiency of NO removal from the gas phase. This paper investigates the mechanism and kinetics of biological Fe(III)EDTA(-) reduction by unadapted anaerobic methanogenic sludge and BioDeNO(x) reactor mixed liquor. The influence of different electron donors, electron mediating compounds and CaSO(3) on the Fe(III)EDTA(-) reduction rate was determined in batch experiments (21mM Fe(III)EDTA(-), 55 degrees C, pH 7.2+/-0.2). The Fe(III)EDTA(-) reduction rate depended on the type of electron donor, the highest rate (13.9mMh(-1)) was observed with glucose, followed by ethanol, acetate and hydrogen. Fe(III)EDTA(-) reduction occurred at a relatively slow (4.1mMh(-1)) rate with methanol as the electron donor. Small amounts (0.5mM) of sulfide, cysteine or elemental sulfur accelerated the Fe(III)EDTA(-) reduction. The amount of iron reduced significantly exceeded the amount that can be formed by the chemical reaction of sulfide with Fe(III)EDTA(-), suggesting that the Fe(III)EDTA(-) reduction was accelerated via an auto-catalytic process with an unidentified electron mediating compound, presumably polysulfides, formed out of the sulfur additives. Using ethanol as electron donor, the specific Fe(III)EDTA(-) reduction rate was linearly related to the amount of sulfide supplied. CaSO(3) (0.5-100mM) inhibited Fe(III)EDTA(-) reduction, probably because SO(3)(2-) scavenged the electron mediating compound.
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Affiliation(s)
- Peter van der Maas
- Sub-department of Environmental Technology, Wageningen University, The Netherlands
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van der Maas P, Manconi I, Klapwijk B, Lens P. Nitric oxide reduction in BioDeNOx reactors: Kinetics and mechanism. Biotechnol Bioeng 2008; 100:1099-107. [DOI: 10.1002/bit.21841] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Manconi I, van der Maas P, Lens P. Effect of copper dosing on sulfide inhibited reduction of nitric and nitrous oxide. Nitric Oxide 2006; 15:400-7. [PMID: 16765618 DOI: 10.1016/j.niox.2006.04.262] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2005] [Revised: 03/27/2006] [Accepted: 04/22/2006] [Indexed: 11/21/2022]
Abstract
The stimulating effect of copper addition on the reduction rate of nitrous oxide (N(2)O) to dinitrogen (N(2)) in the presence of sulfide was investigated in batch experiments (pH 7.0; 55 degrees C). N(2)O was dosed either directly as a gas to the headspace of the bottles or formed as intermediate during the denitrification of nitrite in Fe(II)EDTA(2-)-containing medium and nitrate in Fe(II)EDTA(2-)-free medium. Sulfide was either dosed externally or generated from endogenous sulfur sources during anaerobic incubation of the sludge. In the presence of sulfide (from 15 microM to 1mM), heterotrophic denitrification using ethanol as electron donor was incomplete, i.e., N(2)O accumulated instead of N(2) or was transiently formed. Copper addition (60 microM) rapidly stimulated the reduction of N(2)O to N(2). Zinc addition (60 microM) did not have a similar strong stimulating effect as observed for copper and the N(2)O reduction rate was not stimulated at all upon supply of FeCl(3) (2 mM). Thus, a copper deficiency for N(2)O reduction is most likely developed in the presence of sulfide. It is suggested that sulfide induces this deficiency as it readily precipitates as copper sulfide and thus scavenges copper in the medium or that sulfide inactivates the N(2)OR reductase as it sequesters the copper of this metalloenzyme.
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Affiliation(s)
- Isabella Manconi
- Sub-Department of Environmental Technology, Wageningen University, Bomenweg 2, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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Manconi I, van der Maas P, Lens PNL. Effect of sulfur compounds on biological reduction of nitric oxide in aqueous Fe(II)EDTA2− solutions. Nitric Oxide 2006; 15:40-9. [PMID: 16517188 DOI: 10.1016/j.niox.2005.11.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 10/17/2005] [Accepted: 11/19/2005] [Indexed: 11/20/2022]
Abstract
Biological reduction of nitric oxide (NO) in aqueous solutions of EDTA chelated Fe(II) is one of the main steps in the BioDeNOx process, a novel bioprocess for the removal of nitrogen oxides (NOx) from polluted gas streams. Since NOx contaminated gases usually also contain sulfurous pollutants, the possible interferences of these sulfur compounds with the BioDeNOx process need to be identified. Therefore, the effect of the sulfur compounds Na2SO4, Na2SO3, and H2S on the biological NO reduction in aqueous solutions of Fe(II)EDTA2- (25 mM, pH 7.2, 55 degrees C) was studied in batch experiments. Sulfate and sulfite were found to not affect the reduction rate of Fe(II)EDTA2- complexed NO under the conditions tested. Sulfide, either dosed externally or formed during the batch incubation out of endogenous sulfur sources or the supplied sulfate or sulfite, influences the production and consumption of the intermediate nitrous oxide (N2O) during Fe(II)EDTA2- bound NO reduction. At low concentrations (0.2 g VSS/l) of denitrifying sludge, 0.2 mM free sulfide completely inhibited the nitrosyl-complex reduction. At higher biomass concentrations (1.3-2.3 g VSS/l), sulfide (from 15 microM to 0.8 mM) induced an incomplete NO denitrification with N2O accumulation. The reduction rates of NO to N2O were enhanced by anaerobic sludge, presumably because it kept FeEDTA in the reduced state.
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Affiliation(s)
- Isabella Manconi
- Sub-Department of Environmental Technology, Wageningen University, Bomenweg 2, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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van der Maas P, van den Brink P, Utomo S, Klapwijk B, Lens P. NO removal in continuous BioDeNOx reactors: Fe(II)EDTA2- regeneration, biomass growth, and EDTA degradation. Biotechnol Bioeng 2006; 94:575-84. [PMID: 16596664 DOI: 10.1002/bit.20859] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BioDeNOx is a novel technique for NOx removal from industrial flue gases. In principle, BioDeNOx is based on NO absorption into an aqueous Fe(II)EDTA2- solution combined with biological regeneration of that scrubber liquor in a bioreactor. The technical and economical feasibility of the BioDeNOx concept is strongly determined by high rate biological regeneration of the aqueous Fe(II)EDTA2- scrubber liquor and by EDTA degradation. This investigation deals with the Fe(II)EDTA2- regeneration capacity and EDTA degradation in a lab-scale BioDeNOx reactor (10-20 mM Fe(II)EDTA2-, pH 7.2 +/- 0.2, 55 degrees C), treating an artificial flue gas (1.5 m3/h) containing 60-155 ppm NO and 3.5-3.9% O2. The results obtained show a contradiction between the optimal redox state of the aqueous FeEDTA solution for NO absorption and the biological regeneration. A low redox potential (below -150 mV vs. Ag/AgCl) is needed to obtain a maximal NO removal efficiency from the gas phase via Fe(II)EDTA2- absorption. Fe(III)EDTA- reduction was found to be too slow to keep all FeEDTA in the reduced state. Stimulation of Fe(III)EDTA- reduction via periodical sulfide additions (2 mM spikes twice a week for the conditions applied in this study) was found to be necessary to regenerate the Fe(II)EDTA2- scrubber liquor and to achieve stable operation at redox potentials below -150 mV (pH 7.2 +/- 0.2). However, redox potentials of below -200 mV should be avoided since sulfide accumulation is unwanted because it is toxic for NO reduction. Very low values for biomass growth rate and yield, respectively, 0.043/d and 0.009 mg protein per mg ethanol, were observed. This might be due to substrate limitations, that is the electron acceptors NO and presumably polysulfide, or to physiological stress conditions induced by the EDTA rich medium or by radicals formed in the scrubber upon the oxidation of Fe(II)EDTA2- by oxygen present in the flue gas. Radicals possibly also induce EDTA degradation, which occurs at a substantial rate: 2.1 (+/-0.1) mM/d under the conditions investigated.
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Affiliation(s)
- Peter van der Maas
- Sub-Department of Environmental Technology, Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands
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van der Maas P, van den Bosch P, Klapwijk B, Lens P. NOx removal from flue gas by an integrated physicochemical absorption and biological denitrification process. Biotechnol Bioeng 2005; 90:433-41. [PMID: 15812803 DOI: 10.1002/bit.20420] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An integrated physicochemical and biological technique for NO(x) removal from flue gas, the so-called BioDeNO(x) process, combines the principles of wet absorption of NO in an aqueous Fe(II)EDTA(2-) solution with biological reduction of the sorbed NO in a bioreactor. The biological reduction of NO to di-nitrogen gas (N(2)) takes place under thermophilic conditions (55 degrees C). This study demonstrates the technical feasibility of this BioDeNO(x) concept in a bench-scale installation with a continuous flue gas flow of 650 l.h(-1) (70-500 ppm NO; 0.8-3.3% O(2)). Stable NO removal with an efficiency of at least 70% was obtained in case the artificial flue gas contained 300 ppm NO and 1% O(2) when the bioreactor was inoculated with a denitrifying sludge. An increase of the O(2) concentration of only 0.3% resulted in a rapid elevation of the redox potential (ORP) in the bioreactor, accompanied by a drastic decline of the NO removal efficiency. This was not due to a limitation or inhibition of the NO reduction, but to a limited biological iron reduction capacity. The latter leads to a depletion of the NO absorption capacity of the scrubber liquor, and thus to a poor NO removal efficiency. Bio-augmentation of the reactor mixed liquor with an anaerobic granular sludge with a high Fe(III) reduction capacity successfully improved the bioreactor efficiency and enabled to treat a flue gas containing at least 3.3% O(2) and 500 ppm NO with an NO removal efficiency of over 80%. The ORP in the bioreactor was found to be a proper parameter for the control of the ethanol supply, needed as electron donor for the biological regeneration process. The NO removal efficiency as well as the Fe(III)EDTA(-) reduction rate were found to decline at ORP values higher than -140 mV (pH 7.0). For stable BioDeNO(x) operation, the supply of electron donor (ethanol) can be used to control the ORP below that critical value.
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Affiliation(s)
- Peter van der Maas
- Sub-Department of Environmental Technology, Wageningen University, Bomenweg 2, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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Abstract
The reduction of nitric oxide (NO) in aqueous solutions of Fe(II)EDTA is one of the core processes in BioDeNOx, an integrated physicochemical and biological technique for NO(x)() removal from industrial flue gases. NO reduction in aqueous solutions of Fe(II)EDTA (20-25 mM, pH 7.2 +/- 0.2) was investigated in batch experiments at 55 degrees C. Reduction of NO to N(2) was found to be biologically catalyzed with nitrous oxide (N(2)O) as an intermediate. Various sludges from full-scale denitrifying and anaerobic reactors were capable to catalyze NO reduction under thermophilic conditions. The NO reduction rate was not affected by the presence of ethanol or acetate. EDTA-chelated Fe(II) was found to be a suitable electron donor for the biological reduction of nitric oxide to N(2), with the concomitant formation of Fe(III)EDTA. In the presence of ethanol, EDTA-chelated Fe(III) was reduced to Fe(II)EDTA. This study strongly indicates that redox cycling of FeEDTA plays an important role in the biological denitrification process within the BioDeNOx concept.
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Affiliation(s)
- Peter van der Maas
- Sub-Department of Environmental Technology, Wageningen University, "Biotechnion"-Bomenweg 2, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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