Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Screening for electrical conductivity in anaerobic granular sludge from full-scale wastewater treatment reactors
    Caizán-Juanarena, Leire ; Heijne, Annemiek ter; Weijma, Jan ; Yntema, Doekle ; Suárez-Zuluaga, Diego A. ; Buisman, Cees J.N. - \ 2020
    Biochemical Engineering Journal 159 (2020). - ISSN 1369-703X
    Anaerobic digestion - Anaerobic granules - Direct interspecies electron transfer - Electric current - Elemental composition - Microbial community analysis

    Granulation in bioreactors for the treatment of industrial wastewater is a common phenomenon. Anaerobic granular sludge grown on brewery wastewater is known to manifest electrical conductivity, a characteristic that previously has been related to direct interspecies electron transfer. To assess if this characteristic is more widespread, we determined the electrical conductivity of 28 anaerobic granular sludges grown on a wide variety of industrial wastewaters in full-scale reactors. This revealed that it is a highly variable characteristic: one sludge had a conductivity of 171 μS cm-1 which is 4 times higher than the maximum reported for industrial anaerobic granules, 5 sludges had moderate conductivity ranging from 9.6 to 39 μS cm-1, while the conductivity of the remaining 22 sludges was below 4.5 μS cm-1. Additionally, we studied the possible relation between electrical conductivity and biological, chemical and physical properties of the granules. No clear relationship was found between electrical conductivity and microbial composition, while a positive correlation was found with both the iron and sulfur content. Other correlations were not found. Results suggest that electrical conductivity is a fairly rare characteristic of anaerobic granular sludge. The factors triggering its occurrence, as well as its significance, are not well understood yet.

    Ultrasonic inline inspection of a cement-based drinking water pipeline
    Hernandez Delgadillo, Hector ; Geelen, Caspar ; Kakes, Rutger ; Loendersloot, Richard ; Yntema, Doekle ; Tinga, Tiedo ; Akkerman, Remko - \ 2020
    Engineering Structures 210 (2020). - ISSN 0141-0296
    Cement-based pipeline - Data processing - Degradation - Inline inspection

    The integrity of the drinking water infrastructure deteriorates with time. Monitoring the condition of the drinking water mains can enhance the remaining operational lifetime assessment of the network. In this research a method to translate ultrasonic signals to degradation levels from an inline inspection in a cement-based drinking water pipeline is proposed. The data was obtained from an inspection performed in a Dutch drinking main section. The data is processed in two major steps. Firstly, the parameters that provide the condition of the cement are extracted. Secondly, images of the degradation within the pipes of the inspected trajectory were generated. The main contributions in this paper are (i) the estimation of relative degradation levels of a cement-based pipeline based on the ultrasonic pulse-echo technique and (ii) the upscaling of the processing method in an automated manner for visualization of the degraded condition. Lastly, a sensitivity study of the parameters relevant to the determination of the degraded depth has been performed. The speed of sound in cement is the most relevant parameter to consider. Estimating absolute degradation levels needs further study.

    Combination of bioelectrochemical systems and electrochemical capacitors: Principles, analysis and opportunities
    Caizán-Juanarena, Leire ; Borsje, Casper ; Sleutels, Tom ; Yntema, Doekle ; Santoro, Carlo ; Ieropoulos, Ioannis ; Soavi, Francesca ; Heijne, Annemiek ter - \ 2020
    Biotechnology Advances 39 (2020). - ISSN 0734-9750
    Capacitance - Electrical double-layer - Microbial fuel cell - Power output - Scaling up - Supercapacitor

    Bioelectrochemical systems combine electrodes and reactions driven by microorganisms for many different applications. The conversion of organic material in wastewater into electricity occurs in microbial fuel cells (MFCs). The power densities produced by MFCs are still too low for application. One way of increasing their performance is to combine them with electrochemical capacitors, widely used for charge storage purposes. Capacitive MFCs, i.e. the combination of capacitors and MFCs, allow for energy harvesting and storage and have shown to result in improved power densities, which facilitates the up scaling and application of the technology. This manuscript summarizes the state-of-the-art of combining capacitors with MFCs, starting with the theory and working principle of electrochemical capacitors. We address how different electrochemical measurements can be used to determine (bio)electrochemical capacitance and show how the measurement data can be interpreted. In addition, we present examples of the combination of electrochemical capacitors, both internal and external, that have been used to enhance MFC performance. Finally, we discuss the most promising applications and the main existing challenges for capacitive MFCs.

    Monitoring Support for Water Distribution Systems based on Pressure Sensor Data
    Geelen, Caspar V.C. ; Yntema, Doekle R. ; Molenaar, Jaap ; Keesman, Karel J. - \ 2019
    Water Resources Management 33 (2019)10. - ISSN 0920-4741 - p. 3339 - 3353.
    Early warning system - Proactive leakage control - Real-time learning - Unsupervised learning - Water distribution network (WDS)

    The increasing age and deterioration of drinking water mains is causing an increasing frequency of pipe bursts. Not only are pipe repairs costly, bursts might also lead to contamination of the Dutch non-chlorinated drinking water, as well as damage to other above- and underground infrastructure. Detection and localization of pipe bursts have long been priorities for water distribution companies. Here we present a method for proactive leakage control, referred to as Monitoring Support. Contrary to most leak prevention methods, our method is based on real-time pressure sensor measurements and focuses on detection of recurring pressure anomalies, which are assumed to be indicative of misuse or malfunctioning of the water distribution network. The method visualizes and warns for both recurring and one-time anomalous events and offers monitoring experts an unsupervised decision support tool that requires no training data or manual labeling. Additionally, our method supports any time series data source and can be applied to other types of distribution networks, such as those for gas, electricity and oil. The performance of our method, including both instance-based and feature-based clustering, was validated on two pressure sensor data sets. Results indicate that feature-based clustering is the best method for detection of recurring pressure anomalies, with accuracy F1-scores of 92% and 94% for a 2013 and 2017 data set, respectively.

    Selective Particle Filtering in a Large Acoustophoretic Serpentine Channel
    Kandemir, M.H. ; Wagterveld, R.M. ; Yntema, D.R. ; Keesman, K.J. - \ 2019
    Scientific Reports 9 (2019)1. - ISSN 2045-2322 - 1 p.

    The objective of this study is to investigate the performance of a serpentine channel for acoustically driven selective particle filtering. The channel consists of sharp corners and straight sections, and the acoustic field is affecting the particles throughout the channel. A prototype of the separator channel is manufactured using 3D printing. Acoustic waves are generated by a piezoelectric transducer operating near 2 MHz. Computer simulations are carried out to explore and visualize the flow field and acoustic field in the separator. Selective particle trapping is aimed to be achieved in the hairpin sections, which is confirmed by experiments. Spherical polyethylene particles of 34 µm, 70 µm and 100 µm diameter are used to demonstrate selective trapping by adjusting the flow rate in the channel or voltage input to the transducer. In addition, wheat beer containing yeast up to 20 µm size is selectively filtered by adjusting the flow rate to the channel. Experiments demonstrate that selective particle filtering is possible in the serpentine channel as both methods yield clear separation thresholds.

    Effect of dissolved natural organic matter on the photocatalytic micropollutant removal performance of TiO2 nanotube array
    Ye, Yin ; Bruning, Harry ; Liu, Wanrong ; Rijnaarts, Huub ; Yntema, Doekle - \ 2019
    Journal of Photochemistry and Photobiology. A, Chemistry 371 (2019). - ISSN 1010-6030 - p. 216 - 222.
    MCPA - Micropollutant - Natural organic matter - Photocatalysis - TiO nanotube array

    The TiO2 nanotube array (TNA) is a promising photocatalyst for removal of micropollutants from water, but better understanding on its applicability in complex water matrices is still desired. Therefore this study investigates the effect of dissolved natural organic matter (NOMs) on 4-chloro-2-methylphenoxyacetic acid (MCPA, a typical micropollutant found in many water bodies) removal performance of TNA. The present study shows that although in bulk liquid phase NOMs would undergo photosensitization that can contribute to MCPA removal, the overall effect of NOMs on MCPA removal is detrimental due to the interaction between NOMs and the TNA surface: the total removal of MCPA decreased from 94.3% to 62.0% and 61.8%, in the presence of only 5 mg/L SWR-NOM and UMR-NOM respectively. Acidic pH was found to be able to mitigate the detrimental effect of NOMs (the total removal of MCPA was only decreased from 94.5% to 83.3% and 88.8% under acidic pH, in the presence of 15 mg/L SWR-NOM and UMR-NOM respectively), and the photosensitization effect of NOMs was strengthened; while under alkaline pH conditions the detrimental effect of NOMs completely vanished (the total removal of MCPA increased from 45.7% to 55.7% and 60.5% in the presence of 15 mg/L SWR-NOM and UMR-NOM respectively). Two commonly present co-existing anions, i.e. phosphate and bicarbonate, also mitigate the detrimental effect of NOMs. With 15 mg/L SWR-NOM: the presence of 100 mg/L bicarbonate increased the total removal of MCPA from 49.1% to 65.1%; the presence of 100 mg/L phosphate increased the total removal of MCPA from 49.1% to 62.5%. With 15 mg/L SWR-NOM, the presence of 100 mg/L bicarbonate increased the total removal of MCPA from 45.2% to 56.1%; the presence of 100 mg/L phosphate increased the total removal of MCPA from 45.2% to 62.9%. The photocurrent measurement support that the presence of such anions greatly suppresses the h + scavenging effect of NOMs; while other anions, i.e. chloride, nitrate, sulfate, showed no notable effect.

    SMART detection and real-time learning in water distribution: Pressure Sensor based Monitoring Support
    Geelen, Caspar ; Yntema, D. ; Molenaar, J. ; Keesman, K.J. - \ 2018
    Micropollutant degradation in water by photochemical processes
    Ye, Yin - \ 2018
    Wageningen University. Promotor(en): H.H.M. Rijnaarts, co-promotor(en): H. Bruning; D. Yntema. - Wageningen : Wageningen University - ISBN 9789463433174 - 238

    The increasing legislation pressure, risks associated with micropollutants, and the insufficient efficacy of conventional WWTPs on their removal have formed a joint driving force that is boosting studies on more efficient treatment technology. The general objective of this thesis is to contribute to a better understanding and further development of photochemical treatment processes for micropollutant removal from aqueous streams. Emphasis of this thesis is given to two topics: (1) Further development of UV/TiO2 technique by application of TNA as immobilized catalyst; (2) Development of alternative photochemical water treatment technique for micropollutant removal from wastewater. This thesis demonstrates that: (1) TiO2 nanotube array is a promising immobilized photocatalyst for the removal of micropollutants; (2) Red light induced methylene blue photosensitization provides an efficient process for micropollutants removal.

    Significant enhancement of micropollutant photocatalytic degradation using a TiO2 nanotube array photoanode based photocatalytic fuel cell
    Ye, Yin ; Bruning, Harry ; Li, Xiaolu ; Yntema, Doekle ; Rijnaarts, Huub H.M. - \ 2018
    Chemical Engineering Journal 354 (2018). - ISSN 1385-8947 - p. 553 - 562.
    MCPA - Photocatalysis - Photocatalytic fuel cell - Scavengers - TiO nanotube arrays

    This study evaluated the application of a membrane-free photocatalytic fuel cell composed of a TiO2 nanotube array photoanode and a Cu cathode, i.e. TNA-Cu PFC system, for micropollutant removal from water. Significantly enhanced removal of a commonly present aqueous micropollutant 4-chloro-2-methylphenoxyacetic acid (MCPA) was obtained in this TNA-Cu PFC system: the TNA-Cu PFC system achieved better MCPA degradation compared to the conventional photocatalytic method using the same catalyst. In the TNA-Cu PFC system, the MCPA degradation was largely promoted under acidic conditions, indicating this as an important operational condition. The enhancement of MCPA degradation in the TNA-Cu PFC system involved better e/h+ separation and generation of other oxidants: in conventional photocatalytic process, hydroxyl radicals in liquid phase contributed to 93.7% MCPA degradation while only 2.4% MCPA degradation was mediated by other oxidants like [rad]O2 , H2O2, [rad]HO2; for MCPA degradation in the TNA-Cu PFC system, the contribution of hydroxyl radicals in the liquid phase decreased to 83.6%, while contribution of other oxidants like [rad]O2 , H2O2, [rad]HO2 increased to 15.3%. This change in MCPA degradation mechanisms was confirmed via degradation intermediates analysis by LC-MS/MS. The study on the effect of electrolyte concentration suggests that when operated under acidic conditions, addition of electrolyte is not required. The TNA-Cu PFC system was shown to work well in the presence of up to 15 mg/L natural organic matter (originating from two large rivers), high amounts of common inorganic ions, and even in WWTP effluent. The TNA-Cu PFC system also exhibited relatively good stability after several cycles of repeated use. The obtained results demonstrated that this is an adequate system for micropollutant removal from water at various places in the water cycle, i.e. as polisher of WWTP effluents before discharge or for cleaning intake water before producing drinking water.

    Photocatalytic degradation of metoprolol by TiO2 nanotube arrays and UV-LED : Effects of catalyst properties, operational parameters, commonly present water constituents, and photo-induced reactive species
    Ye, Y. ; Feng, Y. ; Bruning, H. ; Yntema, D. ; Rijnaarts, H.H.M. - \ 2018
    Applied Catalysis B-Environmental 220 (2018). - ISSN 0926-3373 - p. 171 - 181.
    Metoprolol - Photocatalysis - Scavengers - TiO nanotubes - UV-LED
    The aim of this study was to evaluate the use of self-organized TiO2 nanotube arrays (TNAs) as immobilized catalyst and UV-LED as light source (UV-LED/TNAs) for photocatalytic degradation of the β-blocker metoprolol (MTP) from aqueous solution. Firstly we employed electrochemical anodization to synthesize self-organized TNAs, and the effect of anodization potential and annealing temperature was examined. Characterization by SEM demonstrated a linear relation between the diameter of TiO2 nanotubes produced and the anodization potential, while Raman measurement revealed the vital role of annealing on crystallographic composition of the anodic produced TiO2 nanotubes. Regarding their performance in photocatalytic MTP degradation, surface morphology and crystallographic composition of the TNAs were found to impose crucial influence: only TNAs with diameter not smaller than 53 nm enabled rapid MTP degradation, and highest MTP degradation was obtained when a mixture of anatase and rutile were present in the TNAs. Secondly, the effect of operational parameters, i.e initial MTP concentration, pH, was investigated. Initial MTP concentration at low level had no detrimental effect on the process performance. Rapid MTP degradation and high total removal were achieved in a wide pH range (3–11). To evaluate the applicability of TNAs for water treatment, experiments were first carried out in the presence of three different commonly present water constituents, i.e bicarbonate ions, phosphate ions, and natural organic matters (NOMs). The results show that bicarbonate and phosphate ions have no inhibitory effect at concentration levels up to 200 mg/L, and NOMs exhibit detrimental effect when their concentration exceeds 5 mg/L. The total removal MTP degradation reduced from 87.09 ± 0.09% to 62.05 ± 0.08% when tap water samples were applied, demonstrating reasonable efficacy for practical applications. Regarding the degradation mechanism, formic acid and tert-butanol were added as scavenger for photo-generated holes (h+) and hydroxyl radicals (·OH), respectively. The obtained results demonstrate that primary degradation process occurred in liquid phase with participation of hydroxyl radicals in the liquid phase (·OH liquid), while smaller portion of MTP were degraded on the catalysis surface via reaction with h+ and hydroxyl radicals adsorbed on the catalyst surface (·OH surface). Other reactive species, e.g photo generated electrons and superoxide radical anions, did also play a minor role in MTP degradation. The mechanistic aspect was further confirmed by identification of degradation products by LC–MS/MS. The TNAs exhibited good stability after repeated use under varied operation conditions.
    Innovative water system implementation, New ICT and Data Solutions (remote sending). Asset management and big data
    Yntema, D. ; Geelen, Caspar - \ 2017
    Operational parameters affecting MB/Red-light photosensitized degradation of pharmaceuticals
    Ye, Y. ; Luo, Y. ; Bruning, H. ; Yntema, D. ; Rijnaarts, H.H.M. - \ 2017
    Journal of Photochemistry and Photobiology. A, Chemistry 348 (2017). - ISSN 1010-6030 - p. 96 - 101.
    Diclofenac - Methylene blue - Photosensitization - Propranolol - Red light LED - Sulfamethoxazole

    The methylene blue photosensitization under red light irradiation (MB/Red-light) is a promising and powerful tool for removal of pharmaceuticals from wastewater. To further develop this new technology, the present work aimed at studying the effect of operational parameters on the performance of MB/Red-light pharmaceuticals removal processes. Three pharmaceuticals, i.e. diclofenac (DFN), propranolol (PRP), and sulfamethoxazole (SFZ), were used as model compounds, and degradation rate constants and total compound removal were examined. The three operational parameters studied were initial MB concentration (0–5.0 mg/L), initial pharmaceutical concentration (0.1–2.0 mg/L), aeration rate (0–5.0 L/min), and for DFN also the pH. The results show that degradation of pharmaceuticals was promoted with increasing initial MB concentration at values of [MB] below 0.5 mg/L, and leveled off to constant values at [MB] values higher than 2.0 mg/L. Initial pharmaceutical concentration and aeration rate were found to have no significant impact. Moreover, rapid degradation of pharmaceuticals can take place even at low initial dissolved oxygen concentrations (2.0 mg/L, i.e. situations without aeration). In order to better understand the effect of pH on the MB/Red-light pharmaceutical degradation processes, DFN was chosen for more detailed investigation, with identification of the degradation products formed under neutral and alkaline conditions identified by LC–MS/MS. The pH was found to play an important role on the transformation pathways and formation of degradation products.

    Homogeneous photosensitized degradation of pharmaceuticals by using red light LED as light source and methylene blue as photosensitizer
    Ye, Y. ; Bruning, H. ; Yntema, D. ; Mayer, M. ; Rijnaarts, H. - \ 2017
    Chemical Engineering Journal 316 (2017). - ISSN 1385-8947 - p. 872 - 881.
    Methylene blue - Pharmaceuticals - Photosensitization - Red light LED - Singlet oxygen
    Research on employing advanced oxidation processes (AOPs) for pharmaceuticals removal is gaining interests. However, detrimental effects of background water constituents in complex water matrices are limiting their implementation. In this study, we report red light induced methylene blue photosensitization (MB/Red-light) as a promising alternative for pharmaceuticals removal from wastewater, because of its potential to overcome detrimental effects of background water constituents as experienced in other AOP technologies. In this study, the efficacy of MB/Red-light on degradation of four pharmaceutical compounds, i.e. diclofenac (DFN), metoprolol (MTP), propranolol (PRP) and sulfamethoxazole (SFZ), was investigated. The MB/Red-light photosensitization enabled degradation of three model compounds, i.e. DFN, PRP and SFZ. Degradation rates followed the order of DFN > PRP > SFZ. Singlet oxygen was found to be crucial in pharmaceuticals degradation, and another additional mechanism, i.e. a direct reaction with triplet MB, also contributed to DFN degradation. The presence of two DFN degradation mechanisms were confirmed by UV–vis light absorbance spectra measurement as well as the identification of degradation products by LC–MS/MS. Effects of three common back ground water constituents were examined to assess the applicability of MB/red-light system in complex water matrices, which suggests that the MB/red-light system has great potential to be used in real wastewater. Higher pH was found to impose positive impact on the efficacy of the proposed system. Last but not least, red light LED is an optimum light source for the proposed MB/Red-light system, because the light emission spectrum of the LED used in this study fits well with the light absorption spectrum of the photosensitizer-methylene blue.
    Wirelessly powered ultraviolet light emitting diodes for photocatalytic oxidation
    Kuipers, J. ; Bruning, H. ; Yntema, D.R. ; Rijnaarts, H.H.M. - \ 2015
    Journal of Photochemistry and Photobiology. A, Chemistry 299 (2015). - ISSN 1010-6030 - p. 25 - 30.
    heterogeneous photocatalysis - water-treatment - reactor - design - pollutants - systems
    A method is presented to distribute small scale light sources in a photocatalytic slurry reactor. The goal of distributing the light sources is to increase photon transfer efficiency, and thereby increasing the reaction rate, compared to using one single light source. The light sources used in this study were ultraviolet light emitting diodes with a wavelength of 375 nm. An up-flow of air into the photocatalytic reactor distributes the UV-LEDs throughout the reactor, mixes the reaction solution and saturates the solution with molecular oxygen. To make distribution of the UV-LEDs possible, the UV-LEDs were powered wirelessly by resonant inductive coupling. This article shows that UV-LEDs distributed throughout the reactor show a 30% higher removal rate of methylene blue compared to the UV-LEDs concentrated on one plane in the reactor. The removal rate increased linearly with increasing numbers of UV-LEDs. The size of the UV-LEDs determined that up to 32 UV-LEDs could be wirelessly powered in a reactor volume of 500 ml. To increase the reactivity, a higher amount of UV-LEDs per reaction liquid volume and higher radiant power of the UV-LED can be used, bringing use of photocatalytic reactors closer to industrial applications.
    Alternating electric field fluidized bed disinfection performance with different types of granular activated carbon
    Racyte, J. ; Yntema, D.R. ; Kazlauskaite, L. ; DuBois, A. ; Bruning, H. ; Rijnaarts, H.H.M. - \ 2014
    Separation and Purification Technology 132 (2014). - ISSN 1383-5866 - p. 70 - 76.
    waste-water - 3-dimensional electrodes - bacteria - particles - adhesion - viability - removal - system - point - reuse
    The removal of pathogens from effluents is important to promote the reuse of these water resources and safeguarding human health, especially in water scarce areas worldwide. Previously a proof-of-principle of a method for water disinfection consisting of fluidized bed electrodes (FBE) with RX3 EXTRA granular activated carbon (GAC) and a low strength alternating electric field (AC field) in radio frequency range (80–200 kHz) was published. In the study presented here we investigated the mechanistic role of 10 different types of GAC in radio frequency FBE disinfection with Escherichiacoli YMc10 as the model microorganism. The disinfection performances with only GAC, and GAC combined with an AC field were quantified. Seven GACs showed poor to intermediate and three GACs (Norit RB3 (2.7 Log CFU E. coli decrease), Sorbonorit 3 (2.8 Log CFU E. coli decrease) and RX3 EXTRA (3.4 Log CFU E. coli decrease)) showed substantial disinfection in FBE. The results suggest a relation between the pHpzc of the GAC and the disinfection performance. Disinfection performance increased with bigger particle size and decreasing conductivity of tested GACs. We conclude that these physico-chemical and physical properties of GAC are important factors controlling the disinfection performance of these type FBE systems.
    Distributed light sources for photocatalytic water treatment
    Kuipers, J. - \ 2014
    Wageningen University. Promotor(en): Huub Rijnaarts, co-promotor(en): Harry Bruning; D.R. Yntema. - Wageningen : Wageningen University - ISBN 9789462571099 - 198
    waterzuivering - geneesmiddelen - degradatie - lichtdoorlating - katalyse - led lampen - energie - water treatment - drugs - degradation - light transmission - catalysis - led lamps - energy
    In dit proefschrift wordt een nieuwe fotokatalytische reactor met gedistribueerde lichtbronnen gepresenteerd. De nieuwe fotokatalytische reactor maakt gebruik van draadloze energie overdracht om ultraviolet-licht-emitterende diodes (UV-LEDs) van energie te voorzien. De draadloze UV-LEDs worden gedistribueerd door de reactor en verdelen hun licht over het oppervlakte van de fotokatalyst.
    Self-Capacitance and Resistive Losses of Saline-Water-Filled Inductors
    Kuipers, J. ; Bruning, H. ; Yntema, D. ; Bakker, S. ; Rijnaarts, H.H.M. - \ 2014
    IEEE transactions on industrial electronics 61 (2014)5. - ISSN 0278-0046 - p. 2356 - 2361.
    wireless power transfer - core inductors - design - resistance - sensors - systems
    Properties of water-filled inductors are relevant for underwater wireless energy transfer. The influence of the relative permittivity and resistivity of the core material on the impedance of an inductor can be modeled with a lumped parameter circuit. The relative permittivity of the core material has influence on the turn-to-core capacitance of the inductor. The resistivity of the core material has a linear relation with the resistance of the turn-to-turn capacitance. With this model, the influence of the conductivity on the quality factor of an inductor can be predicted. This is a helpful tool to find the optimal frequency at which the quality factor is maximum.
    Alternating electric fields combined with activated carbon for disinfection of Gram negative and Gram positive bacteria in fluidized bed electrode system
    Racyte, J. ; Bernard, S. ; Paulitsch-Fuchs, A.H. ; Yntema, D.R. ; Bruning, H. ; Rijnaarts, H.H.M. - \ 2013
    Water Research 47 (2013)16. - ISSN 0043-1354 - p. 6395 - 6405.
    water treatment plants - urban waste-water - antibiotic-resistance - antimicrobial activity - escherichia-coli - inactivation - particles - cells - flow - viability
    Strong electric fields for disinfection of wastewaters have been employed already for several decades. An innovative approach combining low strength (7 V/cm) alternating electric fields with a granular activated carbon fluidized bed electrode (FBE) for disinfection was presented recently. For disinfection performance of FBE several pure microbial cultures were tested: Bacillus subtilis, Bacillus subtilis subsp. subtilis, Enterococcus faecalis as representatives from Gram positive bacteria and Erwinia carotovora, Pseudomonas luteola, Pseudomonas fluorescens and Escherichia coli YMc10 as representatives from Gram negative bacteria. The alternating electric field amplitude and shape were kept constant. Only the effect of alternating electric field frequency on disinfection performance was investigated. From the bacteria tested, the Gram negative strains were more susceptible and the Gram positive microorganisms were more resistant to FBE disinfection. The collected data indicate that the efficiency of disinfection is frequency and strain dependent. During 6 h of disinfection, the decrease above 2 Log units was achieved with P. luteola and E. coli at 10 kHz and at dual frequency shift keying (FSK) modulated signal with frequencies of 10 kHz and 140 kHz. FBE technology appears to offer a new way for selective bacterial disinfection, however further optimizations are needed on treatment duration, and energy input, to improve effectiveness.
    Alternating field activated carbon fluidized bed electrode for water disinfection
    Racyte, J. - \ 2013
    Wageningen University. Promotor(en): Huub Rijnaarts, co-promotor(en): Harry Bruning; D.R. Yntema. - S.l. : s.n. - ISBN 9789461736260 - 230
    desinfectie - hergebruik van water - afvalwaterbehandeling - verontreinigd water - elektrisch veld - wervelbedden - elektrodes - actieve kool - milieutechnologie - disinfection - water reuse - waste water treatment - polluted water - electric field - fluidized beds - electrodes - activated carbon - environmental technology
    Zoetwaterschaarste is een groot probleem voor de volksgezondheid. Ongeveer 10 % van de wereldbevolking heeft geen toegang tot veilig drinkwater en 36 % van de bevolking heeft geen basis sanitaire voorzieningen. Het grootste deel van deze mensen leeft in waterschaarse gebieden en hergebruik van water is relevant om te voorzien in de benodigde hoeveelheid zoet water. Om meer water te hergebruiken zou behandeld afvalwater gebruikt kunnen worden voor bijvoorbeeld irrigatie. Disinfectie van hergebruikt afvalwater is dan belangrijk om de veiligheid van mens en dier te waarborgen. Een mogelijke alternatieve manier van desinfectie is gebaseerd op het gebruik van elektrische velden. Sterke elektrische velden (bijvoorbeeld als gepulseerde elektrische velden) voor desinfectie van water worden al enige decennia toegepast. Echter, deze technologie maakt gebruik van een sterk elektrisch veld, wat problematisch is voor troebel water die veel organische stof bevatten. Dit kan worden vermeden door gebruik te maken van een zwak, wisselend elektrisch veld gecombineerd met een gefluïdiseerd bed elektrode (FBE) van granulaire actieve kool (GAC). Het doel van dit proefschrift is om het principe aan te tonen van deze FBE desinfectietechnologie en om de belangrijkste componenten van het onderliggende mechanisme te beschrijven.
    Hydrophone pump, container and method therefor
    Kuipers, J. ; Yntema, D.R. ; bakker, S.M. - \ 2012
    Octrooinummer: WO2012047106, gepubliceerd: 2012-04-14.
    The present invention relates to a hydrophone pump, and container and method therefor. The hydrophone pump comprises: - a housing provided with a reactor chamber; - an inlet for admitting and discharging fluid into and out of the reactor chamber; and - a piezo-element provided drivably on at least one side of the reactor chamber.
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