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“Electrochemical in situ pH control enables chemical-free full urine nitrification with concomitant nitrate extraction”. De Paepe J, Clauwaert P, Gritti MC, Ganigue R, Sas B, Vlaeminck SE, Rabaey K, Environmental Science &, Technology 55, 8287 (2021). http://doi.org/10.1021/ACS.EST.1C00041
Abstract: Urine is a valuable resource for nutrient recovery. Stabilization is, however, recommended to prevent urea hydrolysis and the associated risk for ammonia volatilization, uncontrolled precipitation, and malodor. This can be achieved by alkalinization and subsequent biological conversion of urea and ammonia into nitrate (nitrification) and organics into CO2. Yet, without pH control, the extent of nitrification is limited as a result of insufficient alkalinity. This study explored the feasibility of an integrated electrochemical cell to obtain on-demand hydroxide production through water reduction at the cathode, compensating for the acidification caused by nitritation, thereby enabling full nitrification. To deal with the inherent variability of the urine influent composition and bioprocess, the electrochemical cell was steered via a controller, modulating the current based on the pH in the bioreactor. This provided a reliable and innovative alternative to base addition, enabling full nitrification while avoiding the use of chemicals, the logistics associated with base storage and dosing, and the associated increase in salinity. Moreover, the electrochemical cell could be used as an in situ extraction and concentration technology, yielding an acidic concentrated nitrate-rich stream. The make-up of the end product could be tailored by tweaking the process configuration, offering versatility for applications on Earth and in space.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.198
DOI: 10.1021/ACS.EST.1C00041
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“Operational strategies to selectively produce purple bacteria for microbial protein in raceway reactors”. Alloul A, Cerruti M, Adamczyk D, Weissbrodt DG, Vlaeminck SE, Environmental Science &, Technology 55, 8278 (2021). http://doi.org/10.1021/ACS.EST.0C08204
Abstract: Purple non-sulfur bacteria (PNSB) show potential for microbial protein production on wastewater as animal feed. They offer good selectivity (i.e., low microbial diversity and high abundance of one species) when grown anaerobically in the light. However, the cost of closed anaerobic photobioreactors is prohibitive for protein production. Although open raceway reactors are cheaper, their feasibility to selectively grow PNSB is thus far unexplored. This study developed operational strategies to boost PNSB abundance in the biomass of a raceway reactor fed with volatile fatty acids. For a flask reactor run at a 2 day sludge retention time (SRT), matching the chemical oxygen demand (COD) loading rate to the removal rate in the light period prevented substrate availability during the dark period and increased the PNSB abundance from 50-67 to 88-94%. A raceway reactor run at a 2 day SRT showed an increased PNSB abundance from 14 to 56% when oxygen supply was reduced (no stirring at night). The best performance was achieved at the highest surface-to-volume ratio (10 m(2) m(-3) increased light availability) showing productivities up to 0.2 g protein L-1 day(-1) and a PNSB abundance of 78%. This study pioneered in PNSB-based microbial protein production in raceway reactors, yielding high selectivity while avoiding the combined availability of oxygen, COD, and darkness.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.198
DOI: 10.1021/ACS.EST.0C08204
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“Return-sludge treatment with endogenous free nitrous acid limits nitrate production and N₂O emission for mainstream partial nitritation/anammox”. Peng L, Xie Y, Van Beeck W, Zhu W, Van Tendeloo M, Tytgat T, Lebeer S, Vlaeminck SE, Environmental Science &, Technology 54, 5822 (2020). http://doi.org/10.1021/ACS.EST.9B06404
Abstract: Nitrite oxidizing bacteria (NOB) and nitrous oxide (N2O) hinder the development of mainstream partial nitritation/anammox. To overcome these, endogenous free ammonia (FA) and free nitrous acid (FNA), which can be produced in the sidestream, were used for return-sludge treatment for two integrated-film activated sludge reactors containing biomass in flocs and on carriers. The repeated exposure of biomass from one reactor to FA shocks had a limited impact on NOB suppression but inhibited anammox bacteria (AnAOB). In the other reactor, repeated FNA shocks to the separated flocs failed to limit the system’s nitrate production since NOB activity was still high on the biofilms attached to the unexposed carriers. In contrast, the repeated FNA treatment of flocs and carriers favored aerobic ammonium-oxidizing bacteria (AerAOB) over NOB activity with AnAOB negligibly affected. It was further revealed that return-sludge treatment with higher FNA levels led to lower N2O emissions under similar effluent nitrite concentrations. On this basis, weekly 4 h FNA shocks of 2.0 mg of HNO2-N/L were identified as an optimal and realistic treatment, which not only enabled nitrogen removal efficiencies of ∼65% at nitrogen removal rates of ∼130 mg of N/L/d (20 °C) but also yielded the lowest cost and carbon footprint.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 11.4
Times cited: 1
DOI: 10.1021/ACS.EST.9B06404
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“Microstructure characterization of oceanic polyethylene debris”. Rowenczyk L, Dazzi A, Deniset-Besseau A, Beltran V, Goudounèche D, Wong-Wah-Chung P, Boyron O, George M, Fabre P, Roux C, Mingotaud AF, ter Halle A, Environmental Science &, Technology 54, 4102 (2020). http://doi.org/10.1021/ACS.EST.9B07061
Abstract: Plastic pollution has become a worldwide concern. It was demonstrated that plastic breaks down to nanoscale particles in the environment, forming so-called nanoplastics. It is important to understand their ecological impact, but their structure is not elucidated. In this original work, we characterize the microstructure of oceanic polyethylene debris and compare it to the nonweathered objects. Cross sections are analyzed by several emergent mapping techniques. We highlight deep modifications of the debris within a layer a few hundred micrometers thick. The most intense modifications are macromolecule oxidation and a considerable decrease in the molecular weight. The adsorption of organic pollutants and trace metals is also confined to this outer layer. Fragmentation of the oxidized layer of the plastic debris is the most likely source of nanoplastics. Consequently the nanoplastic chemical nature differs greatly from plastics.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 11.4
Times cited: 3
DOI: 10.1021/ACS.EST.9B07061
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“Assessing the origin and fate of CR, Ni, Cu, Zn, Ph, and V in industrial polluted soil by combined microspectroscopic techniques and bulk extraction methods”. Terzano R, Spagnuolo M, Vekemans B, de Nolf W, Janssens K, Falkenberg G, Ruggiero P, Environmental science &, technology 41, 6762 (2007). http://doi.org/10.1021/ES070260H
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 61
DOI: 10.1021/ES070260H
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“Platinum particle size and support effects in NOx mediated carbon oxidation over platinum catalysts”. Villani K, Vermandel W, Smets K, Liang D, Van Tendeloo G, Martens JA, Environmental science &, technology 40, 2727 (2006). http://doi.org/10.1021/es051871h
Abstract: Platinum metal was dispersed on microporous, mesoporous, and nonporous support materials including the zeolites Na-Y, Ba-Y, Ferrierite, ZSM-22, ETS-10, and AlPO-11, alumina, and titania. The oxidation of carbon black loosely mixed with catalyst powder was monitored gravimetrically in a gas stream containing nitric oxide, oxygen, and water. The carbon oxidation activity of the catalysts was found to be uniquely related to the Pt dispersion and little influenced by support type. The optimum dispersion is around 3-4% corresponding to relatively large Pt particle sizes of 2040 nm. The carbon oxidation activity reflects the NO oxidation activity of the platinum catalyst, which reaches an optimum in the 20-40 nm Pt particle size range. The lowest carbon oxidation temperatures were achieved with platinum loaded ZSM-22 and AlPO-11 zeolite crystallites bearing platinum of optimum dispersion on their external surfaces.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.198
Times cited: 29
DOI: 10.1021/es051871h
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