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“Sulfur-based denitrification treating regeneration water from ion exchange at high performance and low cost”. Vandekerckhove TGL, Kobayashi K, Janda J, Van Nevel S, Vlaeminck SE, Bioresource technology 257, 266 (2018). http://doi.org/10.1016/J.BIORTECH.2018.02.047
Abstract: Autotrophic denitrification with sulfur is an underexplored alternative to heterotrophic denitrification to remove nitrate from wastewater poor in organics. The application on ion exchange regeneration water (19.432.1 mS cm−1) is novel. Three fixed bed reactors were tested at 15 °C for >4 months, inoculated with activated sludge from sewage treatment. All were fast in start-up (<10 days) with high performance (94 ± 2% removal efficiency). pH control with NaOH rendered higher nitrate removal rates than limestone addition to the bed (211 ± 13 vs. 102 ± 13 mg N L−1 d−1), related to higher pH (6.64 vs. 6.24) and sulfur surface area. Bacterial communities were strongly enriched in Sulfurimonas (6367%) and Thiobacillus (2426%). In an economic comparison, sulfur-based denitrification (5.3 kg−1 N) was 15% cheaper than methanol-based denitrification (6.22 kg−1 N) and both treatments were opex dominated (85.9 vs. 86.5%). Overall, the technological and economic feasibility should boost further implementation of sulfurotrophic denitrification.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIORTECH.2018.02.047
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“Image analysis and in situ FTIR as complementary detection tools for photocatalytic soot oxidation”. Van Hal M, Verbruggen SW, Yang X-Y, Lenaerts S, Tytgat T, Chemical engineering journal 367, 269 (2019). http://doi.org/10.1016/J.CEJ.2019.02.154
Abstract: Air pollution, especially particulate matter (PM), is an increasingly urgent problem in urban environments, causing both short and long-term health problems, climate interference and aesthetical problems due to building fouling. Photocatalysis has been shown to be a possible solution to that end. In this work two complementary detection methods for photocatalytic soot oxidation are studied and their advantages and disadvantages are discussed. First, a colour-based digital image analysis method is drastically improved towards an accurate, detailed and straightforward detection tool, that enables simultaneous measurement of the degradation of different grades of soot fouling (for instance a shallow soot haze versus condensed soot deposits). In the next part, a second soot oxidation detection method is presented based on in situ FTIR spectroscopy. This method has the additional advantage of providing more insight into the photocatalytic soot degradation process by monitoring both gaseous and adsorbed intermediates as well as reaction products while the reactions are ongoing. As an illustration, the proposed detection strategies were applied on four different commercially available and synthesized photocatalytic materials. The digital image analysis showed that P25 (Evonik) is the fastest photocatalytic soot degrader of all studied materials for both a uniform soot haze as well as concentrated soot spots. Application of the in situ method showed that for all studied materials adsorbed formate-related surface species were formed and that commercially available ZnO nanopowder has the highest specificity towards complete mineralization into CO2. With this we aim to provide a set of complementary experimental tools for the convenient, reliable, realistic and standardised detection of photocatalytic soot degradation.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.216
Times cited: 1
DOI: 10.1016/J.CEJ.2019.02.154
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“Supernatant organics from anaerobic digestion after thermal hydrolysis cause direct and/or diffusional activity loss for nitritation and anammox”. Zhang Q, Vlaeminck SE, DeBarbadillo C, Su C, Al-Omari A, Wett B, Pümpel T, Shaw A, Chandran K, Murthy S, De Clippeleir H, Water research 143, 270 (2018). http://doi.org/10.1016/J.WATRES.2018.06.037
Abstract: Treatment of sewage sludge with a thermal hydrolysis process (THP) followed by anaerobic digestion (AD) enables to boost biogas production and minimize residual sludge volumes. However, the reject water can cause inhibition to aerobic and anoxic ammonium-oxidizing bacteria (AerAOB & AnAOB), the two key microbial groups involved in the deammonification process. Firstly, a detailed investigation elucidated the impact of different organic fractions present in THP-AD return liquor on AerAOB and AnAOB activity. For AnAOB, soluble compounds linked to THP conditions and AD performance caused the main inhibition. Direct inhibition by dissolved organics was also observed for AerAOB, but could be overcome by treating the filtrate with extended aerobic or anaerobic incubation or with activated carbon. AerAOB additionally suffered from particulate and colloidal organics limiting the diffusion of substrates. This was resolved by improving the dewatering process through an optimized flocculant polymer dose and/or addition of coagulant polymer to better capture the large colloidal fraction, especially in case of unstable AD performance. Secondly, a new inhibition model for AerAOB included diffusion-limiting compounds based on the porter-equation, and achieved the best fit with the experimental data, highlighting that AerAOB were highly sensitive to large colloids. Overall, this paper for the first time provides separate identification of organic fractions within THP-AD filtrate causing differential types of inhibition. Moreover, it highlights the combined effect of the performance of THP, AD and dewatering on the downstream autotrophic nitrogen removal kinetics. (C) 2018 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.WATRES.2018.06.037
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“Centralised, decentralised or hybrid sanitation systems? Economic evaluation under urban development uncertainty and phased expansion”. Roefs I, Meulman B, Vreeburg JHG, Spiller M, Water research 109, 274 (2017). http://doi.org/10.1016/J.WATRES.2016.11.051
Abstract: Sanitation systems are built to be robust, that is, they are dimensioned to cope with population growth and other variability that occurs throughout their lifetime. It was recently shown that building sanitation systems in phases is more cost effective than one robust design. This phasing can take place by building small autonomous decentralised units that operate closer to the actual demand. Research has shown that variability and uncertainty in urban development does affect the cost effectiveness of this approach. Previous studies do not, however, consider the entire sanitation system from collection to treatment. The aim of this study is to assess the economic performance of three sanitation systems with different scales and systems characteristics under a variety of urban development pathways. Three systems are studied: (I) a centralised conventional activated sludge treatment, (II) a community on site source separation grey water and black water treatment and (III) a hybrid with grey water treatment at neighbourhood scale and black water treatment off site. A modelling approach is taken that combines a simulation of greenfield urban growth, a model of the wastewater collection and treatment infrastructure design properties and a model that translates design parameters into discounted asset lifetime costs. Monte Carlo simulations are used to evaluate the economic performance under uncertain development trends. Results show that the conventional system outperforms both of the other systems when total discounted lifetime costs are assessed, because it benefits from economies of scale. However, when population growth is lower than expected, the source-separated system is more cost effective, because of reduced idle capacity. The hybrid system is not competitive under any circumstance due to the costly double piping and treatment. (C) 2016 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.WATRES.2016.11.051
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Reniers G, Sö,rensen K, Vrancken K (2013) Management principles of sustainable industrial chemistry : theories, concepts and industrial examples for achieving sustainable chemical products and processes from a non-technological viewpoint. 274 p
Keywords: ME1 Book as editor or co-editor; Economics; Engineering Management (ENM); Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1002/9783527649488
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“Ultrafast screening of commercial sorbent materials for VOC adsorption using real-time FTIR spectroscopy”. Blommaerts N, Dingenen F, Middelkoop V, Savelkouls J, Goemans M, Tytgat T, Verbruggen SW, Lenaerts S, Separation and purification technology 207, 284 (2018). http://doi.org/10.1016/J.SEPPUR.2018.06.062
Abstract: Recovery of valuable volatile organic compounds (VOCs) from waste streams is of great industrial importance. Adsorption on zeolites offers an economically and environmentally friendly alternative to conventional activated carbon. When evaluating the suitability of a given zeolite for a particular adsorption application, its adsorption capacity has to be determined. This is traditionally achieved using gas chromatography as an analysis tool, yielding only a few discrete sampling points that constitute the adsorption profile. Meanwhile, only low flow rates and low concentrations of volatile organics can be used, rendering the procedure troublesome and time consuming. Herein, we propose a tool for the fast screening of a large amount of zeolites using on-line and quasi real-time Fourier Transform Infrared Spectroscopy (FTIR). The technique was used to determine the adsorption capacity of three different commercial zeolites and two silica gels, for five industrially relevant VOCs: acetone; methanol; isohexane; isopentane; and toluene. A series of rapid measurements of the individual adsorption capacities were carried out to obtain a detailed overview of the versatility of the proposed method for the characterization of multi-component and multi-sorption bed systems.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.359
Times cited: 5
DOI: 10.1016/J.SEPPUR.2018.06.062
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“CFD- and radiation field modeling of a gas phase photocatalytic multi-tube reactor”. Roegiers J, van Walsem J, Denys S, Chemical engineering journal 338, 287 (2018). http://doi.org/10.1016/J.CEJ.2018.01.047
Abstract: This paper focusses on the development of a Multiphysics model as a tool for assessing the performance of a multi-tube photoreactor. The model predicts the transient behavior of acetaldehyde concentration, as a model compound for the organic fraction of the indoor air pollutants, under varying sets of conditions. A 3D-model couples radiation field modeling with reaction kinetics and fluid dynamics in order to simulate the transport of the pollutant as it progresses through the reactor. A model-based approach is proposed to determine the layer thickness and refractive index of different P25-powder modified solgel coatings, using an optimization procedure to estimate these parameters based on UV-irradiance measurements. The radiation field model was able to accurately predict the irradiance on the catalytic surface within the reactor. Consequently, the radiation field model was used to define an irradiance dependent reaction rate constant in a coupled Multiphysics model. An optimization routine was deployed to estimate the adsorption, desorption- and photocatalytic reaction rate constants on the TiO2-surface, using experimentally determined, transient outlet concentrations of acetaldehyde. Additionally, a validation test was performed in an air-tight climate chamber at much higher flow rates, higher irradiance and realistic indoor pollutant concentrations to emphasize the reliability and accuracy of the parameters for adsorption, desorption and photocatalytic reaction. The developed model makes it possible to optimize the reactor design and scale-up for commercial applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.CEJ.2018.01.047
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“Recycling of a secondary lead smelting matte by selective citrate leaching of valuable metals and simultaneous recovery of hematite as a secondary resource”. Kim E, Horckmans L, Spooren J, Broos K, Vrancken KCM, Quaghebeur M, Hydrometallurgy 169, 290 (2017). http://doi.org/10.1016/J.HYDROMET.2017.02.007
Abstract: Anew recycling process, according to the zero-waste concept, was investigated for an iron rich waste stream, more specifically a secondary lead smelting matte. The process consists of a selective citrate leaching of Pb, Cu, Ni and Zn in combination with a roasting step, leading to a simultaneous recovery of hematite as a secondary iron resource. The parameters, such as leaching time, leaching temperature, H2O2 concentration and roasting temperature, were experimentally optimized. The maximum Pb leaching efficiency was 93% and the leachability of Cu (33%) and Zn (11%) increased slightly in the presence of 0.5 M H2O2 in 1 M citrate at 25 degrees C and pH 5.5. Importantly, almost no Fe was leached (< 0.6%) from the iron rich matrix material at this condition allowing for a maximal recovery of hematite as a secondary resource after further treatment (i.e. roasting or sulfur removal). The leachability of Pb, Cu, Ni and Zn was strongly affected by the roasting temperature. Maximum leaching efficiency in 1 M citrate (25 degrees C, L/S ratio 10, pH 6.5) was 93% for Pb, 80% for Cu and 60% for Zn at a roasting temperature of 600 degrees C, while for Ni the maximum leaching efficiency of 53% was reached after roasting at 650 degrees C. Furthermore, when oxidative roasting was applied, the leaching residue consists dominantly of hematite (Fe2O3) with minor quantities of PbSO4, which can be used as pig iron ore (Fe > 60 wt%). (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.HYDROMET.2017.02.007
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Goorden L, Van Tendeloo G, Lenaerts S, Deblonde M, et al. (2009) Nanotechnologie: gewikt en gewogen. NanoSoc
Keywords: Minutes and reports; Engineering sciences. Technology; Engineering Management (ENM); Sustainable Energy, Air and Water Technology (DuEL); Electron microscopy for materials research (EMAT)
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Goorden L, Van Tendeloo G, Lenaerts S, Deblonde M, van Oudheusden M, et al. (2009) Nanotechnologie op de agenda. NanoSoc
Keywords: Minutes and reports; Engineering sciences. Technology; Engineering Management (ENM); Society and Environment; Sustainable Energy, Air and Water Technology (DuEL); Electron microscopy for materials research (EMAT)
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“Photoelectrochemistry for measuring the photocatalytic activity of soluble photosensitizers”. Khan SU, Trashin SA, Korostei YS, Dubinina TV, Tomilova LG, Verbruggen SW, De Wael K, ChemPhotoChem 4, 300 (2020). http://doi.org/10.1002/CPTC.201900275
Abstract: We introduce a rapid method to test the photocatalytic activity of singlet‐oxygen‐producing photosensitizers using a batch cell, a LED laser and a conventional potentiostat. The strategy is based on coupling of photo‐oxidation of hydroquinone and simultaneous electrochemical reduction of its oxidized form at a carbon electrode in an organic solvent (methanol). This scheme gives an immediate response and avoids complications related to long‐term experiments such as oxidative photo‐degradation of photosensitizers and singlet oxygen traps by reactive oxygen species (ROS). Among the tested compounds, a fluoro‐substituted subphthalocyanine showed the highest photocurrent and singlet oxygen quantum yield (ΦΔ) in comparison to phenoxy‐ and tert‐butyl‐substituted analogues, whereas the lowest photocurrents and yields were observed for aggregated and dimeric phthalocyanine complexes. The method is useful for fast screening of the photosensitizing activity and represents the first example of one‐pot coupling of electrochemical and photocatalytic reactions in organic media.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.7
Times cited: 1
DOI: 10.1002/CPTC.201900275
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“Titania-functionalized diatom frustules as photocatalyst for indoor air purification”. Ouwehand J, Van Eynde E, De Canck E, Lenaerts S, Verberckmoes A, Van der Voort P, Applied catalysis : B : environmental 226, 303 (2018). http://doi.org/10.1016/J.APCATB.2017.12.063
Abstract: Diatom frustules were extracted from the species Thalassiosira pseudonana and functionalized with titania to be used as photocatalysts in the abatement of acetaldehyde. The synthetic procedure is water-based and environmentally friendly. The synthesis parameters were optimized to give the highest possible photocatalytic activity. The optimized material, visualized with TEM and STEM-EDX, shows the TiO2 nanoparticles grafted inside the frustule pores, as well as on the silica surface. The titania particles, stabilized by the frustules, are 2.5 times more active than the P25 benchmark material. The photocatalyst is then tested in conditions of elevated relative humidity, to simulate indoor air. The catalytic activity only shows a minor decrease at 50% relative humidity, which is a better result than for the P25 benchmark. When tested over an extended period of time, the photocatalyst only shows a minor decrease in activity.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.446
Times cited: 4
DOI: 10.1016/J.APCATB.2017.12.063
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“Correlations between molecular and operational parameters in continuous lab-scale anaerobic reactors”. Carballa M, Smits M, Etchebehere C, Boon N, Verstraete W, Applied microbiology and biotechnology 89, 303 (2011). http://doi.org/10.1007/S00253-010-2858-Y
Abstract: In this study, the microbial community characteristics in continuous lab-scale anaerobic reactors were correlated to reactor functionality using the microbial resource management (MRM) approach. Two molecular techniques, denaturing gradient gel electrophoresis (DGGE) and terminal-restriction fragment length polymorphism (T-RFLP), were applied to analyze the bacterial and archaeal communities, and the results obtained have been compared. Clustering analyses showed a similar discrimination of samples with DGGE and T-RFLP data, with a clear separation between the meso- and thermophilic communities. Both techniques indicate that bacterial and mesophilic communities were richer and more even than archaeal and thermophilic communities, respectively. Remarkably, the community composition was highly dynamic for both Bacteria and Archaea, with a rate of change between 30% and 75% per 18 days, also in stable performing periods. A hypothesis to explain the latter in the context of the converging metabolism in anaerobic processes is proposed. Finally, a more even and diverse bacterial community was found to be statistically representative for a well-functioning reactor as evidenced by a low Ripley index and high biogas production.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1007/S00253-010-2858-Y
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Voordeckers D (2023) Design to breathe : understanding and altering wind patterns in street canyons to reduce human exposure to air pollution. xxii, 303 p
Abstract: Air pollution is proclaimed by the World Health Organiaation (WHO) as the biggest environmental threat to human health. Street canyons, or urban roads flanked by a continuous row of high buildings on both sides, are perceived as typical bottleneck areas for air quality due to their lack of natural ventilation. This doctoral thesis aims to integrate expert knowledge on in-canyon flow fields and pollution dispersion in street canyons from the specialized field of (bio)engineering into the field of urban planning and vice versa. In Chapter 1, a Geospatial Information System (GIS) method was developed to detect exposure zones and hotspot street canyons. A critical combination between aspect ratio (AR > 0.65) and traffic volume (TVmax > 300) was detected and subsequently used to detect hotspot street canyons in three major European cities (Antwerp, London and Paris). Chapter 2 focusses on acquiring in-depth knowledge on flow and concentration fields in street canyons by conducting an extensive literature review on over 200 studies and translates this knowledge into nineteen guidelines and eleven spatial tools, comprised in a toolbox for urban planning. Subsequently, computational fluid dynamics (CFD) was used into a research trough design process (Chapter 4) to illustrate how the design tools can be applied to a specific case study (Belgiëlei, Antwerp). Alternations to traffic lanes (traffic lane reduction and lateral displacement) combined with low boundary walls (LBWs), were found to reduce NO2 levels in the entire pedestrian area up to – 3.6 % and peak pollutions were reduced by -8 %. A maximum NO2 reduction was reached by combining a traffic lane displacement with hedges, adjustments to the tree planting pattern and an increased ground-level permeability, leading to reductions up to – 4.5 % in the pedestrian areas. In conclusion, urban design was found to be a valuable tool to enhance the effect of emission reduction strategies and draw in-canyon concentrations closer to the value of the background concentration. However, the background concentration seemed to dominate the efficiency of the urban design interventions and therefore, additional measures should be taken to reduce background pollution levels. This dissertation aims to contribute to the awareness of air pollution in street canyons, as well as support local governments in taking action by delivering spatial tools and guidelines applicable for urban planning and represents a framework for the dissemination of expert information on air quality in street canyons to the field of urban planning.
Keywords: Doctoral thesis; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Research Group for Urban Development; Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)
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“A multidimensional indicator set to assess the benefits of WEEE material recycling”. Nelen D, Manshoven S, Peeters JR, Vanegas P, D'Haese N, Vrancken K, Journal of cleaner production 83, 305 (2014). http://doi.org/10.1016/J.JCLEPRO.2014.06.094
Abstract: EU strategies for waste management have long recognized the key role of recycling to move towards sustainable consumption and production. This resulted in a range of regulatory measures, among which the Waste Electrical and Electronic Equipment (WEEE) directive, which sets weight-based targets for recovery, preparation for re-use and recycling. The increasing strategic relevance of the supply of raw materials has, however, spurred a more integrated approach towards resource efficiency. In addition to the prevention of disposal, recycling practices are now also meant to contribute to sustainable materials management by pursuing (i) a higher degree of material cycle closure, (ii) an improved recovery of strategically relevant materials, and (iii) the avoidance of environmental burdens associated with the extraction and refining of primary raw materials. In response to this evolution, this paper reports about the development of an indicator set that allows to quantitatively demonstrate these recycling benefits, hence going further than the weight-based objectives employed in the WEEE directive. The indicators can be calculated for WEEE recycling processes for which information is available on both input and output fractions. It offers a comprehensive framework that aims to support decision making processes on product design, to identify opportunities for the optimization of WEEE End-of-Life scenarios, and to assess the achieved (or expected) results of implemented (or planned) recycling optimization strategies. The paper is illustrated by a case study on the recycling of LCD televisions. (C) 2014 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.JCLEPRO.2014.06.094
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“Wintertime spatio-temporal variation of ultrafine particles in a Belgian city”. Mishra VK, Kumar P, Van Poppel M, Bleux N, Frijns E, Reggente M, Berghmans P, Int Panis L, Samson R, The science of the total environment 431, 307 (2012). http://doi.org/10.1016/J.SCITOTENV.2012.05.054
Abstract: Simultaneous measurements of ultrafine particles (UFPs) were carried out at four sampling locations situated within a 1 km(2) grid area in a Belgian city, Borgerhout (Antwerp). All sampling sites had different orientation and height of buildings and dissimilar levels of anthropogenic activities (mainly traffic volume). The aims were to investigate: (i) the spatio-temporal variation of UFP within the area, (ii) the effect of wind direction with respect to the volume of traffic on UFP levels, and (iii) the spatial representativeness of the official monitoring station situated in the study area. All sampling sites followed similar diurnal patterns of UFP variation, but effects of local traffic emissions were evident. Wind direction also had a profound influence on UFP concentrations at certain sites. The results indicated a clear influence of local weather conditions and the more dominant effect of traffic volumes. Our analysis indicated that the regional air quality monitoring station represented the other sampling sites in the study area reasonably well; temporal patterns were found to be comparable though the absolute average concentrations showed differences of up to 35%. (C) 2012 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.SCITOTENV.2012.05.054
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“Resolving the unresolved complex mixture in motor oils using high-performance liquid chromatography followed by comprehensive two-dimensional gas chromatography”. Mao D, van de Weghe H, Lookman R, Vanermen G, de Brucker N, Diels L, Fuel 88, 312 (2009). http://doi.org/10.1016/J.FUEL.2008.08.021
Abstract: High-performance liquid chromatography (HPLC) followed by comprehensive two-dimensional gas chromatography (GC×GC) was used for detailed group-type characterization of hydrocarbons present in motor oils. With conventional GC, motor oil is not well separated due to its complexity, resulting in a hump in the chromatogram: the unresolved complex mixture (UCM). With HPLC-GC×GC, motor oil hydrocarbons can be quantitatively separated into four major groups: alkanes, cycloalkanes, alkenes and aromatics. Each group can be further separated and divided by ring number or carbon number. Three selected motor oil samples were characterized by HPLC-GC×GC including two conventional motor oils and a synthetic motor oil. Using a proprietary silver-modified HPLC column, the aromatic components in motor oils were baseline separated from the aliphatic UCM and were then further separated by GC×GC based on their aromatic ring numbers. Accordingly, the aliphatic components were separated by GC×GC based on their saturated ring numbers. This paper illustrates the capabilities of HPLC-GC×GC for reliable and detailed quantitative group-type characterization of hydrocarbons present in motor oils.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.FUEL.2008.08.021
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“The benefit of glass bead supports for efficient gas phase photocatalysis : case study of a commercial and a synthesised photocatalyst”. Verbruggen SW, Ribbens S, Tytgat T, Hauchecorne B, Smits M, Meynen V, Cool P, Martens JA, Lenaerts S, Chemical engineering journal 174, 318 (2011). http://doi.org/10.1016/J.CEJ.2011.09.038
Abstract: In the field of photocatalytic air purification, the immobilisation of catalyst particles on support surfaces without loss of photon efficiency is an important challenge. Therefore, an immobilisation method involving a one-step suspension coating of pre-synthesised photocatalysts on glass beads was applied. The various benefits are exemplified in the gas phase photodegradation of ethylene. Coating of glass beads is easy, fast, cheap and offers a more efficient alternative to bulk catalyst pellets. Furthermore, this coating procedure allows to use porous, pre-synthesised catalysts to their full potential, as the surface area and morphology of the initial powder is barely altered after coating, in strong contrast to pelletising. With this technique it became possible to study the gas phase photocatalytic activity of commercial titanium dioxide, trititanate nanotubes and mixed phase anatase/trititanate nanotubes in a packed bed reactor towards the degradation of ethylene without changing the catalyst properties. Coating of glass beads with the photocatalyst revealed the superior activity of the as-prepared nanotubes, compared to TiO2 Aerolyst® 7710 in gaseous phase.
Keywords: A1 Journal article; Engineering sciences. Technology; Laboratory of adsorption and catalysis (LADCA); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.216
Times cited: 39
DOI: 10.1016/J.CEJ.2011.09.038
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“Nonlinear dispersive model of electroporation for irregular nucleated cells”. Chiapperino MA, Bia P, Caratelli D, Gielis J, Mescia L, Dermol-Cerne J, Miklavcic D, Bioelectromagnetics 40, 331 (2019). http://doi.org/10.1002/BEM.22197
Abstract: In this work, the electroporation phenomenon induced by pulsed electric field on different nucleated biological cells is studied. A nonlinear, non-local, dispersive, and space-time multiphysics model based on Maxwell's and asymptotic Smoluchowski's equations has been developed to calculate the transmembrane voltage and pore density on both plasma and nuclear membrane perimeters. The irregular cell shape has been modeled by incorporating in the numerical algorithm the analytical functions pertaining to Gielis curves. The dielectric dispersion of the cell media has been modeled considering the multi-relaxation Debye-based relationship. Two different irregular nucleated cells have been investigated and their response has been studied applying both the dispersive and non-dispersive models. By a comparison of the obtained results, differences can be highlighted confirming the need to make use of the dispersive model to effectively investigate the cell response in terms of transmembrane voltages, pore densities, and electroporation opening angle, especially when irregular cell shapes and short electric pulses are considered. Bioelectromagnetics. 2019;40:331-342. (c) 2019 Wiley Periodicals, Inc.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1002/BEM.22197
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“Dispersion modelling of traffic induced ultrafine particles in a street canyon in Antwerp, Belgium and comparison with observations”. Nikolova I, Janssen S, Vos P, Vrancken K, Mishra V, Berghmans P, The science of the total environment 412, 336 (2011). http://doi.org/10.1016/J.SCITOTENV.2011.09.081
Abstract: The aim of this study is to investigate the dispersion of ultrafine particles and its spatial distribution in a street canyon and its neighbourhood with the 3D CFD model ENVI-met®. The performance of the model at street scale is evaluated and the importance of the boundary conditions like wind field and traffic emissions on the UFP concentration is demonstrated. To support and validate the modelled results, a short-term measurement campaign was conducted in a street canyon in Antwerp, Belgium. The UFP concentration was measured simultaneously with P-TRACK (TSI Model 8525) at four different locations in the canyon. The modelled UFP concentrations compare well with the measured data (correlation coefficient R from 0.44 to 0.93) within the standard deviation of the measurements. Despite the moderate traffic flow in the street canyon, UFP concentrations in the canyon are in general double of the background concentrations, indicating the high local contribution for this particle number concentration. Some of the observed concentration profiles are not resembled by the model simulations. For these specific anomalies, further analysis is performed and plausible explanations are put forward. The role of wind direction and traffic emissions is investigated. The performance evaluation of ENVI-met® shows that in general the model qualitatively and quantitatively describes the dispersion of UFP in the street canyon study.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.SCITOTENV.2011.09.081
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“Overcoming floc formation limitations in high-rate activated sludge systems”. Van Winckel T, Liu X, Vlaeminck SE, Takács I, Al-Omari A, Sturm B, Kjellerup BV, Murthy SN, De Clippeleir H, Chemosphere 215, 342 (2019). http://doi.org/10.1016/J.CHEMOSPHERE.2018.09.169
Abstract: High-rate activated sludge (HRAS) is an essential cornerstone of the pursuit towards energy positive sewage treatment through maximizing capture of organics. The capture efficiency heavily relies on the degree of solid separation achieved in the clarifiers. Limitations in the floc formation process commonly emerge in HRAS systems, with detrimental consequences for the capture of organics. This study pinpointed and overcame floc formation limitations present in full-scale HRAS reactors. Orthokinetic flocculation tests were performed with varying shear, sludge concentration, and coagulant or flocculant addition. These were analyzed with traditional and novel settling parameters and extracellular polymeric substances (EPS) measurements. HRAS was limited by insufficient collision efficiency and occurred because the solids retention time (SRT) was short and colloid loading was high. The limitation was predominantly caused by impaired flocculation rather than coagulation. In addition, the collision efficiency limitation was driven by EPS composition (low protein over polysaccharide ratio) instead of total EPS amount. Collision efficiency limitation was successfully overcome by bio-augmenting sludge from a biological nutrient removal reactor operating at long SRT which did not show any floc formation limitations. However, this action brought up a floc strength limitation. The latter was not correlated with EPS composition, but rather EPS amount and hindered settling parameters, which determined floc morphology. With this, an analysis toolkit was proposed that will enable design engineers and operators to tackle activated solid separation challenges found in HRAS systems and maximize the recovery potential of the process. (C) 2018 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.CHEMOSPHERE.2018.09.169
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“Influence of pH on urine nitrification : community shifts of ammonia-oxidizing bacteria and inhibition of nitrite-oxidizing bacteria”. Faust V, Vlaeminck SE, Ganigué, R, Udert KM, ACS ES&T engineering 4, 342 (2024). http://doi.org/10.1021/ACSESTENGG.3C00320
Abstract: Urine nitrification is pH-sensitive due to limited alkalinity and high residual ammonium concentrations. This study aimed to investigate how the pH affects nitrogen conversion and the microbial community of urine nitrification with a pH-based feeding strategy. First, kinetic parameters for NH3, HNO2, and NO2– limitation and inhibition were determined for nitrifiers from a urine nitrification reactor. The turning point for ammonia-oxidizing bacteria (AOB), i.e., the substrate concentration at which a further increase would lead to a decrease in activity due to inhibitory effects, was at an NH3 concentration of 12 mg-N L–1, which was reached only at pH values above 7. The total nitrite turning point for nitrite-oxidizing bacteria (NOB) was pH-dependent, e.g., 18 mg-N L–1 at pH 6.3. Second, four years of data from two 120 L reactors were analyzed, showing that stable nitrification with low nitrite was most likely between pH 5.8 and 6.7. And third, six 12 L urine nitrification reactors were operated at total nitrogen concentrations of 1300 and 3600 mg-N L–1 and pH values between 2.5 and 8.5. At pH 6, the AOB Nitrosomonas europaea was found, and the NOB belonged to the genus Nitrobacter. At pH 7, nitrite accumulated, and Nitrosomonas halophila was the dominant AOB. NOB were inhibited by HNO2 accumulation. At pH 8.5, the AOB Nitrosomonas stercoris became dominant, and NH3 inhibited NOB. Without influent, the pH dropped to 2.5 due to the growth of the acid-tolerant AOB “Candidatus Nitrosacidococcus urinae”. In conclusion, pH is a decisive process control parameter for urine nitrification by influencing the selection and kinetics of nitrifiers.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1021/ACSESTENGG.3C00320
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“Approach of describing dynamic production of volatile fatty acids from sludge alkaline fermentation”. Wang D, Liu Y, Ngo HH, Zhang C, Yang Q, Peng L, He D, Zeng G, Li X, Ni B-J, Bioresource technology 238, 343 (2017). http://doi.org/10.1016/J.BIORTECH.2017.04.054
Abstract: In this work, a mathematical model was developed to describe the dynamics of fermentation products in sludge alkaline fermentation systems for the first time. In this model, the impacts of alkaline fermentation on sludge disintegration, hydrolysis, acidogenesis, acetogenesis, and methanogenesis processes are specifically considered for describing the high-level formation of fermentation products. The model proposed successfully reproduced the experimental data obtained from five independent sludge alkaline fermentation studies. The modeling results showed that alkaline fermentation largely facilitated the disintegration, acidogenesis, and acetogenesis processes and severely inhibited methanogenesis process. With the pH increase from 7.0 to 10.0, the disintegration, acidogenesis, and acetogenesis processes respectively increased by 53%, 1030%, and 30% while methane production decreased by 3800%.However, no substantial effect on hydrolysis process was found. The model also indicated that the pathway of acetoclastic methanogenesis was more severely inhibited by alkaline condition than that of hydrogentrophic methanogenesis. (C) 2017 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIORTECH.2017.04.054
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“About some methods of analytic representation and classification of a wide set of geometric figures with “complex” configuration”. Tavkhelidze I, Gielis J, Pinelas S page 347 (2020).
Keywords: H1 Book chapter; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1007/978-3-030-56323-3_27
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Gielis J (2023) Fred Van Oystaeyen : Time hybrids: a new generic theory of reality. 347–351
Keywords: Review; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.26830/SYMMETRY_2023_3_357
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“Elaborating the membrane life concept in a full scale hollow-fibers MBR”. Fenu A, De Wilde W, Gaertner M, Weemaes M, de Gueldre G, van de Steene B, Journal of membrane science 421, 349 (2012). http://doi.org/10.1016/J.MEMSCI.2012.08.001
Abstract: The membrane life-time has a strong impact on competitivity and viability of MBRs. This study critically analyzes the membrane life-time concept, approaching it through different assessment methods. A full scale MBR's membrane life-time was assessed on the following: (i) maintaining the permeate flow throughput to the MBR; (ii) the permeability decline; (iii) oxidative aging; (iv) the increase in energy costs; and (v) mechanical aging. The method based on permeability decline provides a membrane life-time estimate up to a theoretical end. It was further elaborated inherently to operations with no long-term flux decline. The increase in operating pressure remains the main end-of-life trigger for deciding when to replace membrane modules. On the contrary, mechanical and permeate flow throughput analysis of the data are not able to provide a clear estimate of the membrane life-time. As for the membrane life-time estimation based on chlorine contact, it was found to be too optimistic. Complete irreversible fouling occurs before maximum contact time with chlorine is reached. At end-of-life operating conditions, the energy consumption raised of 170% due to the reduced flow rate. The cost raise appears high but still affordable. Earlier membrane replacement thus can never be counterbalanced by energy costs saving. (C) 2012 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.MEMSCI.2012.08.001
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“Kinetics of growth and lipids accumulation in Chlorella vulgaris during batch heterotrophic cultivation : effect of different nutrient limitation strategies”. Sakarika M, Kornaros M, Bioresource technology 243, 356 (2017). http://doi.org/10.1016/J.BIORTECH.2017.06.110
Abstract: The present study aimed at: (1) determining the effect of sulfur addition on biomass growth and (2) assessing the effect of sulfur, phosphorus and nitrogen limitation on lipid accumulation by C. vulgaris SAG 211-11b. The sulfur cellular content was more than two-fold higher under nitrogen and phosphorus limitation (0.52% and 0.54% w w(-1), respectively) compared to sulfur requirements (0.20% w w(-1)) under sulfur limiting conditions. The nitrogen needs are significantly lower (2.81-3.35% w w(-1)) when compared to other microalgae and become 23% lower under nitrogen or phosphorus limitation. The microalga exhibited substrate inhibition above 30 g L-1 initial glucose concentration. Sulfur limitation had the most significant effect on lipid accumulation, resulting in maximum total lipid content of 53.43 +/- 3.93% g g(DW)(1). In addition to enhancing lipid productivity, adopting the optimal nutrient limitation strategy can result in cost savings by avoiding unnecessary nutrient additions and eliminate the environmental burden due to wasted resources. (C) 2017 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIORTECH.2017.06.110
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“In-situ chromium and vanadium recovery of landfilled ferrochromium and stainless steel slags”. Spooren J, Kim E, Horckmans L, Broos K, Nielsen P, Quaghebeur M, Chemical engineering journal 303, 359 (2016). http://doi.org/10.1016/J.CEJ.2016.05.128
Abstract: A novel heap leaching method was investigated for selective removal of chromium (Cr) and-vanadium (V) from ferrochromium (FeCr) and stainless steel (SS) slags. In particular, alkaline oxidative heap leaching was simulated on lab-scale by batch and column leaching tests. The results show a selective leaching of Cr (11-19%) and V (7.0-7.5%) after 64 days of column leaching, with a very low dissolution (<2.2% (FeCr slag) and <0.15% (SS slag)) of matrix elements (e.g. Al, Fe, Si, Mg, Ca), when NaOCl is applied as oxidation agent and NaOH as alkaline agent. Furthermore, the used leaching liquor is reactive for a longer period of time, indicating that circulation of leaching liquor could be possible. Finally, the experimental results were fed into a first-order model which predicts that Cr will continue to leach from the tested slags for 4-5 years at a chosen infiltration rate of 73,000 l/(y m(2)). (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.CEJ.2016.05.128
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“The circular economy potential of reversible bonding in smartphones”. Parchomenko A, De Smet S, Pals E, Vanderreydt I, Van Opstal W, Sustainable Production and Consumption 41, 362 (2023). http://doi.org/10.1016/J.SPC.2023.08.017
Abstract: The increased use of adhesive bonding in manufacturing is an important barrier to implement circular economy strategies, including repair, refurbishment, and high-quality recycling. The circular economy potential of reversible adhesives that are debondable on demand, however, remains largely unexplored. In this paper we apply an integrated technology-agnostic framework to smartphones to identify and quantify the circular econ-omy potential of reversible bonding. In this framework we combine insights from Life Cycle Assessment, Life Cycle Costing, and Statistical Entropy Analysis. We find that reversible bonding of smartphones can be an enabler for circular strategies and have a considerable positive impact on preserving higher functionality on a product, component, and material level. The major added value of reversible bonding is its potential to replace and update parts, retaining the main environmental hotspot of a smartphone. Firms, however, will not likely switch to this technology, even though bonding and debonding make up only a small fraction of total lifecycle costs. Therefore, policy recommendations include mandatory policies on repairability and public procurement favouring the use of reversible bonding techniques. This would alter incentives in contexts where consumer preferences for lease markets cannot be taken for granted. The evaluation of different debonding scenarios from three distinct per-spectives provides a comprehensive, more reliable, and robust understanding of the trade-offs related to debonding and its potential contribution to the circular economy.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 12.1
DOI: 10.1016/J.SPC.2023.08.017
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“Towards a more direct policy feedback in circular economy monitoring via a societal needs perspective”. Alaerts L, Van Acker K, Rousseau S, De Jaeger S, Moraga G, Dewulf J, De Meester S, Van Passel S, Compernolle T, Bachus K, Vrancken K, Eyckmans J, Resources, conservation and recycling 149, 363 (2019). http://doi.org/10.1016/J.RESCONREC.2019.06.004
Abstract: The increasing focus on circular economy at the level of governments and policy requires the development of appropriate indicators to effectively monitor the progress towards the circular economy. Currently two very different types of indicator areas are under development: (i) monitoring frameworks based on macro indicators that summarize the progress at (supra)national level, and (ii) micro indicators tailored towards assessing circularity at the level of products. It is not possible to obtain sufficiently direct feedback about the impact of policy interventions by either macro or micro indicators alone. In this paper, a conceptual approach is developed that aims to bridge the gap between the micro and macro level with meso level indicators, and thus ultimately deliver more direct feedback for policymakers, via the insertion of an extra level of meso indicators in between the macro and the micro level. These indicators have been extracted from a dedicated workshop that involved policy, sector and societal stakeholders. The aim of these indicators is to report on progress towards circular economy objectives based on the fulfillment of societal needs. In this way the consumption perspective is given a central position, and the role of circular business models is acknowledged. Following the development of the concept, the next steps towards tailored, flexible and agile monitoring frameworks for circular economy at (supra)national and regional level are outlined. The paper concludes with an illustrative example of the framework applied to the mobility system.
Keywords: A1 Journal article; Economics; Engineering Management (ENM); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.313
Times cited: 1
DOI: 10.1016/J.RESCONREC.2019.06.004
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