Articles de revues : « Oxidising treatment »

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Schramm, Andreas, Dirk De Beer, Han van den Heuvel, Simon Ottengraf et Rudolf Amann. « In situ structure/function studies in wastewater treatment systems ». Water Science and Technology 37, n^o 4-5 (1 février 1998) : 413–16. http://dx.doi.org/10.2166/wst.1998.0681.

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As an example of the importance and the potential of in situ structure/function studies, nitrifying aggregates from different zones of a lab-scale fluidised bed reactor were analysed by microelectrode measurements of O2, NH4+, NO2−, and NO3− and in situ hybridisation targeting the 16S rRNA of the nitrifying bacteria. A shift from an ammonia oxidising to a nitrite oxidising community is present along the reactor. In the single aggregates an active nitrifying shell of about 100 μm could be related to the maximum abundance of nitrifiers in this zone. Interestingly, the main actors in this system are not representatives of the well-described genera Nitrosomonas and Nitrobacter but some other ammonia oxidisers from the beta subclass of Proteobacteria and a thus far unknown nitrite oxidising population.

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Laloo, Andrew Elohim, et Philip L. Bond. « Engineering biological nitrogen removal in wastewater treatment via the control of nitrite oxidising bacteria using free nitrous acid ». Microbiology Australia 39, n^o 1 (2018) : 47. http://dx.doi.org/10.1071/ma18012.

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Nitrogen compounds need to be removed or captured from wastewater streams before disposal to protect our aquatic environments from eutrophication. Particular bacteria facilitating the biological removal of nitrogen during wastewater treatment include ammonia oxidising bacteria (AOB), nitrite oxidising bacteria (NOB), denitrifiers, as well as anaerobic ammonium oxidising (Anammox) bacteria. Manipulating these microbial communities can improve efficiency in nitrogen removal. Bypassing nitrate production by selectively inhibiting NOB reduces the need for oxygen and the addition of external carbon for the nitrogen removal. Various approaches to selectively inhibit NOB in the nitrification process are available. Here we present an approach using the biocide, free nitrous acid (FNA) to selectively suppress NOB growth thereby improving the efficiency of the nitrogen removal process.

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Burrell, Paul, Jürg Keller et Linda L. Blackall. « Characterisation of the bacterial consortium involved in nitrite oxidation in activated sludge ». Water Science and Technology 39, n^o 6 (1 mars 1999) : 45–52. http://dx.doi.org/10.2166/wst.1999.0257.

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A sequencing batch reactor (SBR) was operated to selectively grow a nitrite oxidising microbial community and was called the nitrite oxidising SBR (NOSBR). The nitrite oxidising characteristics of the reactor biomass were studied as well as the microbial composition. Molecular biological methods of clone libraries were used to evaluate the microorganisms in both the seed sludge and in the NOSBR sludge. We have found that the nitrite oxidation in the NOSBR was due the presence of bacteria from the Nitrospira phylum and not because of the presence of Nitrobacter which were in very low numbers in the NOSBR and not detected in the seed sludge. We hypothesize that the unknown nitrite oxidising bacteria in wastewater treatment plants are a range of species related to Nitrospira moscoviensis. A suite of primers were developed from the clone sequence data and used in a diagnostic polymerase chain reaction to prove the presence of these novel nitrite oxidisers in a range of full scale and laboratory scale activated sludge plants.

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Nguyen, Huu Dong, Thi Viet Nguyen, Thi Thu Hang Dinh, Do Hung Phan Do et Hoa Duan Tran. « Ammonia oxidation capacity of bacillus bacteria in swine wastewater after biogas treatment ». Hue University Journal of Science : Natural Science 131, n^o 1D (31 décembre 2022) : 77–87. http://dx.doi.org/10.26459/hueunijns.v131i1d.7006.

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Nitrogen removal with biological methods plays a crucial role in wastewater treatment technology. The treatment begins with the oxidation of ammonia to nitrite to facilitate the subsequent nitrification and denitrification. Various strains of ammonia-oxidising bacteria have been reported. In this study, we use three Bacillus bacteria isolated from swine wastewater to oxidise ammonia. Different initial densities (103, 104, 105, and 106 CFU·mL–1) of each strain were examined. The results show that the combination of all the bacteria at a ratio of 1:1:1 and a density of 105 CFU·mL–1 exhibits the most effect. The findings contribute to the diversity of ammonia-oxidising bacterial species and pose a great potential for applying these strains in wastewater treatment.

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Deswaef, S., T. Salmon, S. Hiligsmann, X. Taillieu, N. Milande, Ph Thonart et M. Crine. « Treatment of gypsum waste in a two stage anaerobic reactor ». Water Science and Technology 34, n^o 5-6 (1 septembre 1996) : 367–74. http://dx.doi.org/10.2166/wst.1996.0572.

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The reduction of high concentrations of gypsum (up to 110 kg/m3) is investigated in a two stage immobilised cell bioreactor. The first stage is mainly colonised by a consortium of acidogenic bacteria and sulphate reducing bacteria oxidising volatile fatty acids with more than 2 carbons (mainly, butyrate and propionate). The gypsum consumption rate is rather high (11 kg/m3.day). Most of acetate remains unconverted in this first stage. It is partially converted in the second stage (residence time : 12 days) which is predominantly colonised by acetate oxidising bacteria. The gypsum consumption rate is much lower than in the first stage: 3 kg/m3.day. With both stages, it is possible to reach an almost complete conversion of gypsum with an overall capacity of 6.1 kg gypsum/m3.day. We propose also a very simple model to describe the different transformation rates. It allows us to clearly identify the activity levels of the different types of sulphate reducing bacteria in both stages.

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Dinh, Thi Thu Hang, Thi Viet Nguyen, Do Hung Phan, Hoa Duan Tran, Dang Giang Chau Nguyen et Huu Dong Nguyen. « Nitrite metabolism of several bacterial strains isolated from abattoir and swine wastewater after biogas treatment ». Hue University Journal of Science : Natural Science 131, n^o 1D (31 décembre 2022) : 105–14. http://dx.doi.org/10.26459/hueunijns.v131i1d.7007.

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In nitrogen treatment with biological methods, nitrite metabolism is an intermediate process that facilitates other processes involving different bacteria strains. In this study, we isolated two nitrite-oxidising bacteria strains from abattoir wastewater and wastewater from biogas tanks of an industrial pig farm in Ha Tinh province. The bacteria strains grow, develop, and metabolise nitrite at pH 6–8 and 30–37 °C. The samples with the nitrite concentration up to 750 mg·L–1 were oxidised within four days of incubation, and the nitrite metabolism rate was proportional to the concentration of nitrite tested. Under severe conditions (salinity up to 3% NaCl, a low dissolved oxygen level of 0.1 mg·L–1), the two isolated bacterial strains exhibited their effective growth and nitrite metabolism capacity. The results enrich the database of nitrite-oxidising bacteria and are prospective in wastewater treatment.

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Béline, F., H. Boursier, F. Guiziou et E. Paul. « Modelling of biological nitrogen removal during treatment of piggery wastewater ». Water Science and Technology 55, n^o 10 (1 mai 2007) : 11–19. http://dx.doi.org/10.2166/wst.2007.301.

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During this study, a mathematical model simulating piggery wastewater treatment was developed, with the objective of process optimisation. To achieve this, the effect of temperature and free ammonia concentration on the nitrification rate were experimentally studied using respirometry. The maximum growth rates obtained were higher for ammonium-oxidising biomass than for nitrite-oxidising biomass for the temperatures above 20 °C; values at 35 °C were equal to 1.9 and 1.35 day−1, respectively. No inhibition of nitrification was observed for free ammonia concentrations up to 50 mgN/L. Using these data with others experimental data obtained from a pilot-scale reactor to treat piggery wastewater, a model based on a modified version of the ASM1 was developed and calibrated. In order to model the nitrite accumulation observed, the ASM1 model was extended with a two-step nitrification and denitrification including nitrite as intermediate. Finally, the produced model called PiWaT1 demonstrated a good fit with the experimental data. In addition to the temperature, oxygen concentration was identified as an important factor influencing the nitrite accumulation during nitrification. Even if some improvements of the model are still necessary, this model can already be used for process improvement.

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Beolchini, F., S. Ubaldini, B. Passariello, N. Gül, D. Türe, Francesco Vegliò, R. Danovaro et A. Dell'Anno. « Bioremediation of Dredged Sediments Polluted by Heavy Metals ». Advanced Materials Research 20-21 (juillet 2007) : 307–10. http://dx.doi.org/10.4028/www.scientific.net/amr.20-21.307.

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The present work deals with a bioremediation study of a heavy-metal polluted harbour sediment, obtained from the Italian Adriatic Coast. Bioleaching of the sediment sample was performed with a mixed culture of acidophilic, chemi-autotrophic Fe/S oxidising bacteria. The effect of an anaerobic biostimulation pre-treatment on the extent of Cd, Cu, Zn, Ni, Pb, Hg, As, Cr extraction by bioleaching was evaluated. The biostimulation pre-treatment was intended to stimulate autochthonous sulfate reducing strains, to enhance the sulfide fraction in the sediment, to favour subsequent activity of reduced-sulfur-oxidizing bacteria in the subsequent bioaugmentation (bioleaching). The effect of the duration of anaerobic pre-treatment (21 and 30 days) in the presence and absence of 1% glucose was tested. The results obtained showed that the activity of the reducedsulfur- oxidising strains was significantly enhanced after an anaerobic pre-treatment of the sediments and showed real promise for the application of bioleaching for metal polluted sediments.

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CYDZIK-KWIATKOWSKA, AGNIESZKA, MAGDALENA ZIELIŃSKA et IRENA WOJNOWSKA-BARYŁA. « Impact of Operational Parameters on Bacterial Community in a Full-Scale Municipal Wastewater Treatment Plant ». Polish Journal of Microbiology 61, n^o 1 (2012) : 41–49. http://dx.doi.org/10.33073/pjm-2012-005.

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A bacterial community in activated sludge from a full-scale municipal wastewater treatment plant was monitored throughout the year with the use of FISH, RISA and DGGE techniques. In the investigated range of temperatures (11.9-21.6 degrees C), a rise in temperature resulted in a lower total bacteria richness, while organic load rate changes from 0.09 to 0.21 g COD x g TSS(-1) x d(-1) were positively correlated with the number of bands in RISA patterns. The most diverse pattern (29 different bands) was characteristic for the activated sludge sample collected at the end of January at wastewater temperature of 11.9 degrees C. The ammonia-oxidising bacteria community did not change during the study, and comprised of 4 different bacterial populations with one dominant species closely related to Nitrosospira sp. REGAU (GenBank accession number AY635572.1). The percentage of ammonia-oxidising bacteria in the activated sludge varied from 6.2 to 19.5% and depended on temperature (R = 0.61, p = 0:02) and organic load rate (R = -0.55, p = 0.04).

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Kovalev, Rodion. « Study of the heat treatment effect of medium-temperature electrode pitch on carbonisate yield ». From Chemistry Towards Technology Step-By-Step 5, n^o 4 (23 décembre 2024) : 113–20. https://doi.org/10.52957/2782-1900-2024-5-4-113-120.

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Coal tar pitch is a residue of coal tar separation. It is widely used as a binder in the production of electrodes and anode mass. The production of pectic carbonisates and the development of methods to increase the value of its yield is of scientific and applied interest. The author conducted experiments on heat treatment in oxidising medium of medium-temperature electrode pitch of category BsTmelt = 71.5 °C (AO Altai-Koks, Russia). We conducted the process of heat treatment of the pitch in a 5.6 litre reactor heated by using an integrated electric heating system. To enhance the increase of Tmelt during heat treatment, we pumped the gas phase products from the reactor to a collection tank where they condensed. We performed heat treatment at T > 400 °C using both thermal oxidation of pitch and pumping of distillates. We formed the oxidising environment by supplying air by a compressor to the molten pitch. The air supply process started after the holding temperature was reached. The temperature controller provided the holding temperature. The author determined the yield of thermo-oxidation products, melting temperatures Tmelt, and volatile yields X for the resulting products. We obtained pitch with Tmelt = 140 °C and 158 °C. However, this heat treatment significantly reduced the yield of volatile substances in the final products. The temperature of carbonisation of heat-treated pitch was T = 650 °C and T = 850 °C. Therefore, research determines the carbonisate yields. Moreover, carbonisation proceeds with the additional holding times at 450 °C and 650 °C. Hence, heat treatment increased the carbonisate yield by 10%. Holding times at 450 °C and 650 °C also quantitatively increased the yield of carbonisate.

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Haneke, J., V. Siemers et H. F. A. Van den Weghe. « Nitrification processes in scrubbing liquid of an exhaust air treatment system of a large-scale pig housing facility ». Water Science and Technology 64, n^o 10 (1 novembre 2011) : 2009–15. http://dx.doi.org/10.2166/wst.2011.793.

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The use of multi-staged exhaust air treatment systems is an effective method of substantially reducing the emission of ammonia, dust particles and odorous substances. Wet filter walls are able to absorb large amounts of ammonia when scrubbing fluid containing sulphuric acid is used. In addition, due to their large surface areas and the permanent supply of oxygen and nutrients, wet filter walls provide a basis for the development of biofilms containing nitrogen-converting bacteria. Cyclic nitrification processes could be observed in a two-stage exhaust air treatment system, which had been converted to function as a regulated process control system (elutriation at κ = 20 mS cm−1; pH 6.5–6.8). With this system, the sulphuric acid requirement was periodically reduced every 6–8 weeks to less than 1 kg H2SO4 per fattening place and year. There was an increased formation of nitrous oxide gas during nitrification after the wet filter stage. Electron-microscopic images of the biofilm growing on the wet filter wall showed aggregates of possible ammonium-oxidising and nitrite-oxidising bacteria.

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Gagnaire, J., X. Y. Wang, L. Chapon, P. Moulin et B. Marrot. « Kinetic study of compost liquor nitrification ». Water Science and Technology 63, n^o 5 (1 mars 2011) : 868–76. http://dx.doi.org/10.2166/wst.2011.263.

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This study is a first kinetic approach about the compost liquor treatment by activated sludge. This industrial wastewater is highly loaded in organic and nitrogen compounds (COD≈12,000 mg L−1 and NH4+-N≈4,000 mg L−1). The possibility of its treatment in an urban WWTP is studied measuring ammonia oxidation rate with non-acclimated sludge to the industrial effluent. Compost liquor appears as an inhibitor substrate. The ammonia oxidation rate can be modelled by the Haldane model: UMAX=0.180 d−1, KS=12.0 mgN.L−1 and KI=26.0 mgN.L−1. The ammonia oxidation rate also follows for a synthetic substrate which has the same pollutant load as the real substrate. In this case, the ammonia oxidation rate can be modelled by the Monod model: UMAX=0.073 d−1 and KS=4.3 mgN.L−1. This result confirms that the ammonia oxidising bacteria are inhibited by the real wastewater. The following-up of nitrate production shows also the inhibition of nitrite oxidising bacteria. The compost liquor treatment seems not possible in an urban WWTP (<50,000 p.e.). That’s why a specific WWTP is recommended and an acclimation step of activated sludge is essential.

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Brözel, V. S., B. Pietersen et T. E. Cloete. « Resistance of bacterial cultures to non-oxidising water treatment bactericides by adaptation ». Water Science and Technology 31, n^o 5-6 (1 mars 1995) : 169–75. http://dx.doi.org/10.2166/wst.1995.0592.

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Bacterial communities in water cooling systems treated with bactericides often become resistant to these bactericides. This has been ascribed to selection for resistant cells. Certain bacteria, having a high inherent susceptibility to water treatment bactericides become dominant in systems after bactericide treatment. We investigated the idea that bacterial isolates adapt to grow in the presence of bactericides. Pure cultures of Pseudomonas aeruginosa, P stutzeri and Bacillus cereus were cultured repeatedly in the presence of sub-inhibitory concentrations of 2,2′-methylenebis(4-chlorophenol), Na dimethyldithiocarbamate, isothiazolone and alkyl dimethyl ammonium chloride. All isolates adapted to grow in the presence of increasing concentrations of the bactericides. The phenomenon of development of bacterial resistance to water treatment bactericides was ascribed to adaptation and not to selection.

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Yaskiv, O., I. Pohrelyuk, D.-B. Lee, V. Fedirko et S. Guryn. « Carbo-oxidising of titanium by diffusion treatment in carbon–oxygen containing media ». International Heat Treatment and Surface Engineering 6, n^o 2 (juin 2012) : 72–79. http://dx.doi.org/10.1179/1749514812z.00000000023.

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Nam, N. V. T., M. T. Luong, N. Yu Yudina, O. N. Ponamoreva, S. V. Alferov, T. N. L. Chi, N. T. Dung, Ph T. M. Duyen et V. T. Nghia. « Distribution of nitrogen-transforming bacteria in an artificial reservoir populated with aquatic higher plants ». Proceedings of Universities. Applied Chemistry and Biotechnology 12, n^o 4 (2 janvier 2023) : 589–98. http://dx.doi.org/10.21285/2227-2925-2022-12-4-589-598.

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This article examines the distribution of nitrogen-transforming bacteria in an artificial reservoir (pond) populated with aquatic higher plants of common reed (Phragmites australis) and cattail (Typha) for treating swine wastewater. In the pond occupied by Phragmites australis, 7 strains of ammonium oxidising and 14 denitrifying bacteria were identified, while, in the pond occupied by Typha, 6 strains of ammonium oxidising and 19 denitrifying bacteria were distinguished. A comparative analysis of bacterial count at various sampling points revealed their decrease along the artificial pond. Most of the bacteria strains oxidising ammonium were identified in the samples collected from the surface layer of the pond, while denitrifying bacteria dominated the bottom layer. The isolated microorganisms identified by 16S rRNA sequencing belonged to the genus Pantoea, Enterobacter and Bacillus. An artificial pond having aquatic higher plants is characterised by a diverse microbiota, whose composition strongly depends on the wastewater source rather than on the cultivated plant species. The ammonia transformation and denitrification capacity of isolated bacterial strains was determined. The highest conversion efficiency of ammonia (up to 56%) was observed for Enterobacter cloacae bacteria isolated from the surface layer of the pond. Denitrifying bacteria sampled from the bottom layer allowed for the reduction in nitrate content from 20 to 10 mg/L in 72 h. The obtained results confirm the role of bacteria in the treatment of wastewater against nitrogen-containing pollutants, with the average efficiency of removal of inorganic nitrogen compounds being 50%.

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Kreuzinger, N., A. Farnleitner, G. Wandl, R. Hornek et R. Mach. « Molecular biological methods (DGGE) as a tool to investigate nitrification inhibition in wastewater treatment ». Water Science and Technology 47, n^o 11 (1 juin 2003) : 165–72. http://dx.doi.org/10.2166/wst.2003.0601.

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Incomplete nitrification at an activated sludge plant for biological pre-treatment of rendering plant effluents led to a detailed investigation on the origin and solution of this problem. Preliminary studies revealed that an inhibition of ammonia oxidising microorganisms (AOM) by process waters of the rendering plant was responsible for the situation. We were able to show a correlation between the existence of specific AOM and nitrification capacity expressed as oxygen uptake rate for maximal nitrification (OURNmax). Only Nitrosospira sp. was found in the activated sludge of the rendering plant and another industrial wastewater treatment plant with problems in nitrification, while reference plants without nitrification problems showed Nitrosomonas spp. as the predominant ammonia oxidising bacteria. By accompanying engineering investigations and experiments (cross-feeding experiments, operation of a two-stage laboratory plant) with molecular biological methods (DGGE - Denaturing Gradient Gel Electrophoresis) we were able to elaborate an applicable solution for the rendering plant. Laboratory experiments with a two-stage process layout finally provided complete nitrification overcoming the inhibiting nature of process waters from the rendering plant. DGGE analysis of the second stage activated sludge from the laboratory plant showed a shift in population structure from Nitrosospira sp. towards Nitrosomonas spp. simultaneous to the increase of nitrification capacity. Nitrification capacities comparable to full-scale municipal wastewater treatment plants could be maintained for more than two months. As the design of wastewater treatment plants for nitrification is linked to the growth characteristics of Nitrosomonas spp., established criteria can be applied for the redesign of the full-scale plant.

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Hickey, N., P. Fornasiero, R. Di Monte, J. Kašpar, J. R. González-Velasco, M. A. Gutiérrez-Ortiz, M. P. González-Marcos, J. M. Gatica et S. Bernal. « Reactivation of aged model Pd/Ce0.68Zr0.32O2three-way catalyst by high temperature oxidising treatment ». Chem. Commun., n^o 2 (2004) : 196–97. http://dx.doi.org/10.1039/b308321g.

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Karthikeyan, K., et Bhaarathi Dhurai. « NEW METHOD OF DISCHARGE PRINTING ON COTTON FABRICS USING HORSERADISH PEROXIDASE ». AUTEX Research Journal 11, n^o 2 (1 juin 2011) : 61–65. http://dx.doi.org/10.1515/aut-2011-110206.

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Abstract Textile discharge printing is the most versatile and important of the methods used for introducing design to textile fabrics. In discharge styles, the pattern is produced by the chemical destruction of the original dye in the printed areas. The discharging agents used can be oxidising or reducing agents, acids, alkalis and various salts. However, the most important methods of discharging are based formaldehyde sulphoxylates and thiourea dioxide. Recently, environmental and industrial safety concerns have increased the potential for the use of enzymes in textile processing to ensure eco-friendly production. Formaldehyde sulphoxylate (NaHSO2.CH2O.2H2O) is one of the most powerful discharging agents; however, it is quite toxic and produces formaldehyde, a known human carcinogen associated with nasal sinus cancer and nasopharyngeal cancer. In this work, a hazardous chemical has been replaced with eco-friendly horseradish peroxidase enzyme in textile discharge printing. Enzymatic discharge printing was carried out with a phenol oxidising enzyme system such that the reactive dye was selectively discharged from the cotton fabric in selected areas, creating a printed surface. The effects of enzyme concentration, pH of the printing paste, treatment time and the temperature of enzymatic treatment were studied. The optimum conditions for enzymatic discharge printing were found to be pH 8.5 at 70°C with a dye concentration of 80 g/L and 60 min as the treatment time.

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Khtatba, Khalid, Seyed Amir Paknejad, Ali Mansourian et Samjid H. Mannan. « Sintered Silver Die Attach with Extreme Thermal Stability for Extreme and Dynamic Environments ». Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2017, HiTEN (1 juillet 2017) : 000168–76. http://dx.doi.org/10.4071/2380-4491.2017.hiten.168.

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Abstract: The surface oxidation of internal pore surfaces of nano-scale sintered silver has increased stability for high temperature applications. After treatment, high temperature storage at 400 °C has resulted in no changes to microstructure. By contrast, it is known that the microstructure of untreated pressure-less sintered silver continuously evolves at temperatures above 200 °C. Grain and pore growth occur in this temperature range for conventional sintered silver resulting in coarsening of the microstructure and increased susceptibility to fatigue. However, oxidation treatment of the internal pore surfaces has the effect of freezing the microstructure when the contact metallization is also silver or chemically inert. Oxidation prevents mass transfer by shutting down the fastest atomic migration route along the internal pore surfaces. Samples exhibited no change in microstructure either through continuous observation through glass, or after cross sectioning. The tested specimens under high temperature storage resisted grain growth for the whole duration of the tests of more than 600 h at 300 °C. The only detectable changes in microstructure occurred in a sparse number of isolated grains (1 in 7000 grains), presumably due to non-penetration of oxidising treatment into these closed pore spaces. It is hypothesized that even these can be prevented by minor changes to the sintering paste to slightly increase initial porosity. The oxidising treatment can be performed via many different routes, such as exposure to steam, or even by dipping in water for 10 min.

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Stan, Catalina Daniela, Igor Cretescu, Cristina Pastravanu, Ioannis Poulios et Maria Drăgan. « Treatment of Pesticides in Wastewater by Heterogeneous and Homogeneous Photocatalysis ». International Journal of Photoenergy 2012 (2012) : 1–6. http://dx.doi.org/10.1155/2012/194823.

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The effect of different heterogeneous and homogeneous photocatalytic systems on the oxidative degradation of mepiquat chloride in aqueous solutions was investigated. In the case of heterogeneous reactions, the influence of five factors was studied: the type of catalyst, photocatalyst concentration, pH, pesticide concentration, and the presence of H2O2and/or Fe3+. For homogeneous catalysis, other factors were studied: the oxidising agent and the light source. Nearly complete degradation of mepiquat chloride was obtained after about 180 minutes in the presence of an acid medium (pH3) using a UV-A lamp and TiO2P-25 catalyst (0.5 g/L), for an initial pesticide concentration of 10 ppm. Degradation rates corresponding to homogeneous photocatalysis were lower compared to those corresponding to the use of TiO2as the photocatalyst.

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Lee, Wen Si, Hamidi Abdul Aziz et Husnul Azan Tajarudin. « A recent development on iron-oxidising bacteria (IOB) applications in water and wastewater treatment ». Journal of Water Process Engineering 49 (octobre 2022) : 103109. http://dx.doi.org/10.1016/j.jwpe.2022.103109.

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Ayare, Sudesh D., et Parag R. Gogate. « Sonophotocatalytic oxidation based treatment of phthalocyanine pigment containing industrial wastewater intensified using oxidising agents ». Separation and Purification Technology 233 (février 2020) : 115979. http://dx.doi.org/10.1016/j.seppur.2019.115979.

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Lambert, S. D., et K. E. McGrath. « Can stored sludge cake be deodorised by chemical or biological treatment ? » Water Science and Technology 41, n^o 6 (1 mars 2000) : 133–39. http://dx.doi.org/10.2166/wst.2000.0102.

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The storage of sludge cake provides an opportunity for septicity to develop, withattendant odours. Moreover, the odour prevention, containment and minimisation procedures used successfully in the rest of the works may not be adaptable to sludge storage and subsequent transport and disposal. Odourscan be released throughout storage and, in addition, the subsequent movement of the cake can release high concentrations of odours which have accumulated. This paper focuses on the use of five types of chemical and biological treatment product to remediate odour in stored cake sludges: oxidising agents, bacteriological/enzymatic preparations, biological suppressants, nutrients, and odour neutralisers. Their action is described in terms of their effects on the microbial population of the sludge, the types of odours they are designed to eradicate, and how they are used in practice.

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El-Tarabily, Khaled A., Abdou A. Soaud, Maher E. Saleh et Satoshi Matsumoto. « Isolation and characterisation of sulfur-oxidising bacteria, including strains of Rhizobium, from calcareous sandy soils and their effects on nutrient uptake and growth of maize (Zea mays L.) ». Australian Journal of Agricultural Research 57, n^o 1 (2006) : 101. http://dx.doi.org/10.1071/ar04237.

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Four sulfur-oxidising bacteria were selected among 427 bacterial isolates from calcareous sandy soils in the United Arab Emirates (UAE). These isolates were selected based on their strong ability to oxidise elemental sulfur (S°) in vitro and were identified as Paracoccus versutus CBS 114155, Paracoccus pantotrophus CBS 114154, and 2 strains as Rhizobium spp. NCCB 100053 and NCCB 100054. This is the first published report of a Rhizobium species capable of S° oxidation and also the first record of sulfur-oxidising bacteria from UAE soils. These isolates were tested in a greenhouse in the presence and absence of S° to study their effects on maize growth. Best growth was observed in the treatment with P. versutus application combined with S°, which significantly reduced soil pH, increased soil SO4 level and the uptake of N, S, Fe, Mn, and Zn in maize roots and shoots. The P and Cu uptake in the shoots of maize plants was not significant compared with the treatment that received the application of S° alone. There was no response in plant growth to treatments that included the application of S° combined with P. pantotrophus or Rhizobium strain NCCB 100053 compared with the treatment that received the application of S° alone. There was significant growth inhibition of maize plants in the treatment receiving Rhizobium strain NCCB 100054 with or without the application of S° compared with the treatment that included the application of S° alone. This growth inhibition was associated with a significant decrease in the levels of N, P, S, Fe, Mn, Zn, and Cu in roots and shoots in the absence of S°. Rhizobium strain NCCB 100054 applied with S° significantly decreased the levels of N, S, and Fe in the roots and the levels of N, P, S, Fe, Mn, and Cu in the shoots of maize, with no significant differences in the levels of P and Mn in the roots and in the levels of Zn in the shoots, compared with the treatment with S° alone. These results indicate that the treatment P. versutus combined with S° can be effective as a soil conditioner for horticultural production in calcareous sandy soils.

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Kennedy, Nabla, Richard D. Lally, Siobhán W. Walsh, David N. Dowling et David Ryan. « Effect of green waste and lime amendments on biostabilisation, physical-chemical and microbial properties of the composted fine fraction of residual municipal solid waste ». Waste Management & ; Research : The Journal for a Sustainable Circular Economy 39, n^o 8 (5 mars 2021) : 1069–77. http://dx.doi.org/10.1177/0734242x21996823.

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Implementation of guidelines to reduce the amount of biodegradable municipal waste (BMW) sent to landfill has created a need in the waste-management industry to investigate possible methods of accelerating biostabilisation of residual BMW. The effect of commercially feasible manipulations (lime and green waste (GW)) on the rate of biostabilisation of the fine (<20 mm) fraction of residual BMW was investigated. The physical and chemical attributes of the composted wastes were measured, and their bacterial communities profiled using traditional culture-based methods. In addition, ammonia-oxidising microbes were monitored during the biostabilisation process using molecular profiling methods. Addition of GW accelerated biostabilisation, reduced conductivity and increased the levels of ammonia-oxidising bacterial (AOB) and archaeal (AOA) genes. The best stability was noted in the dual (Lime + GW) treatment, which was under the limit of 13 mmol O2 kg DM−1 h−1 recommended by the Irish compost standard. Biostabilised wastes met recommendations for source-segregated compost for pH (6-8) and pathogens ( E. coli and Salmonella), but not heavy metals, indicating their unsuitability for uses other than landfill cover. Levels of AOA genes (log 3–6 g−1 DM) were higher than AOB (log 1–6 g−1 DM, indicating AOA may contribute more to potential ammonia oxidation in residual BMW composting.

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Balzano, S., T. Jamieson et S. Leterme. « Changes in microbial communities during seawater pre-treatment within a desalination plant ». Aquatic Microbial Ecology 86 (11 mars 2021) : 63–68. http://dx.doi.org/10.3354/ame01958.

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We analysed prokaryotic and eukaryotic communities across the seawater pre-treatment system of Penneshaw (Kangaroo Island, South Australia) desalination plant, using 16S and 18S rRNA gene sequencing. The richness of operational taxonomic units increased downstream of the pre-treatment system (reverse osmosis feedwater) compared to raw seawater for Archaea, while it decreased for bacteria and protists. Overall, the reverse osmosis feedwater was found to be enriched in ammonia-oxidising bacteria and Archaea compared to raw seawater, and also contained greater proportions of taxa typically observed in aquatic biofilms and/or within other water treatment systems. Although the microbial load was reduced by the pre-treatment system, the increase in proportion of biofilm-associated microbes suggests the presence of active microbial communities within multimedia filters and other parts of the pre-treatment system that might increase biofouling risks.

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Pietrzak, Robert, Helena Wachowska et Piotr Nowicki. « The effect of flame coal oxidation on the solid and soluble products of its extraction ». Open Chemistry 3, n^o 4 (1 décembre 2005) : 852–65. http://dx.doi.org/10.2478/bf02475208.

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AbstractSolid and soluble products of THF and CH2Cl2 extraction of flame coal oxidised by four different oxidising agents (peroxyacetic acid (PAA), 5% HNO3, O2/Na2CO3, air/125 °C) were studied by elemental analysis and FTIR. The extraction yield with THF was much higher than that with CH2Cl2 for all samples. The greatest changes in elemental composition were in the extracts from coal oxidised by nitric acid. The sulphur content was lowest in extracts from coal oxidised with 5% HNO3 and PAA. FTIR confirmed that coal treatment with nitric acid incorporates nitrogen into the coal structure.

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Jardin, N., et J. Hennerkes. « Full-scale experience with the deammonification process to treat high strength sludge water – a case study ». Water Science and Technology 65, n^o 3 (1 février 2012) : 447–55. http://dx.doi.org/10.2166/wst.2012.867.

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More stringent effluent criteria with regard to nitrogen calls for improved nutrient removal techniques in wastewater treatment plants (WWTPs). Besides optimisation of the liquid treatment train of the plants, attention has increasingly centred on the problem of return flows from sludge treatment. One of the most recent developments aimed at the reduction of this nitrogen load is deammonification which has been used at one of Ruhrverband's plants since 2002 by applying a moving bed system. To gain additional experience in operating this process, another full scale plant was modified in 2007 by integration of deammonification, using a SBR system with suspended biomass based on the DEMON® control scheme. By using seeding sludge from Strass WWTP in Austria, start-up has been achieved within only 1 day. After stable operation for several months, increasing nitrate concentrations were observed in the effluent of the system indicating growing activity of nitrite oxidising bacteria (NOB). Following severe process deterioration, it was decided to re-start the system again but the same behaviour, i.e. increasing levels of nitrate, was observed once again. Several approaches were used to suppress NOB organisms in full-scale without success, e.g. low oxygen levels and high free ammonia concentrations. Finally, the reduction of the aerobic cycle length during intermittent aeration down to 8 min, followed by an anoxic mixing period of only 18 min was successful in inhibiting the activity of NOB organisms, most probably due to their elevated lag-phase compared with ammonium oxidising bacteria. Today, nitrogen elimination that has been stabilised at more than 80% at a daily volumetric loading rate of 0.5 kg N/(m3 d). The total costs amount to €2.3/kg Neli.

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Tietz, A., R. Hornek, G. Langergraber, N. Kreuzinger et R. Haberl. « Diversity of ammonia oxidising bacteria in a vertical flow constructed wetland ». Water Science and Technology 56, n^o 3 (1 août 2007) : 241–47. http://dx.doi.org/10.2166/wst.2007.505.

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Vertical flow constructed wetlands (VFCWs) with intermittent loading are very suitable for nitrification. Ammonia oxidising bacteria (AOB) are the limiting step of nitration. Therefore the AOB community of a full-scale VFCW, receiving municipal wastewater, was investigated within this study. The diversity of the functional gene encoding the α–subunit of the ammonia monooxygenase (amoA), present only in AOB, was assessed by denaturing gradient gel electrophoresis (DGGE). Only very few amoA sequence types dominated the wetland filter substrate; nevertheless a stable nitrification performance could be observed. During the cold season the nitrification was slightly reduced, but it has been shown that the same AOB could be identified. No spatial AOB pattern could be observed within the filter body of the VFCW. The most prominent bands were excised from DGGE gels and sequenced. Sequence analyses revealed two dominant AOB lineages: Nitrosomonas europaea/“Nitrosococcus mobilis” and Nitrosospira. Species of the Nitrosomonas lineage are commonly found in conventional wastewater treatment plants (WWTPs). In contrast, members of the Nitrosospira lineage are rarely present in WWTPs. Our observations indicate that the AOB community in this VFCW is similar to that found in horizontal flow constructed wetlands, but differs from common WWTPs regarding the presence of Nitrosospira.

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Freudenhammer, H., D. Bahnemann, L. Bousselmi, S. U. Geissen, A. Ghrabi, F. Saleh, A. Si-Salah, U. Siemon et A. Vogelpohl. « Detoxification and recycling of wastewater by solar-catalytic treatment ». Water Science and Technology 35, n^o 4 (1 février 1997) : 149–56. http://dx.doi.org/10.2166/wst.1997.0107.

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An introduction to a joint research project is given which deals with the technical application of solar photocatalysis for wastewater detoxification. A non-concentrating thin-film fixed-bed reactor (TFFBR) is used to study applications and areas where a solar-catalytic treatment or recycling of wastewater is possible. This reactor excels by its low cost and an easy-to-build construction using molecular oxygen in air as the oxidising agent. The design parameters of the reactor as well as the process itself have been determined from the reaction kinetics of a model substance, the hydrodynamics and the mass transfer. The treatment of different real wastewaters was successfully carried out, and biologically pre-treated textile wastewater maximum solar degradation rate was about 3 g COD h−1 m−2. A comparison of reaction rates with artifical and solar illumination shows the necessity of outdoor experiments. Due to the reaction rates observed, photocatalysis is suitable as the final stage of purification of biologically or physically pretreated wastewater and will offer a great opportunity for sunrich areas.

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Araujo, J. C., M. M. S. Correa, E. C. Silva, A. P. Campos, V. M. Godinho, M. Von Sperling et C. A. L. Chernicharo. « Investigation of aerobic and anaerobic ammonium-oxidising bacteria presence in a small full-scale wastewater treatment system comprised by UASB reactor and three polishing ponds ». Water Science and Technology 61, n^o 3 (1 février 2010) : 737–43. http://dx.doi.org/10.2166/wst.2010.955.

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This work applied PCR amplification method and Fluorescence in situ hybridisation (FISH) with primers and probes specific for the anammox organisms and aerobic ammonia-oxidising β-Proteobacteria in order to detect these groups in different samples from a wastewater treatment system comprised by UASB reactor and three polishing (maturation) ponds in series. Seven primer pairs were used in order to detect Anammox bacteria. Positive results were obtained with three of them, suggesting that Anammox could be present in polishing pond sediments. However, Anammox bacteria were not detected by FISH, indicating that they were not present in sediment samples, or they could be present but below FISH detection limit. Aerobic ammonia- and nitrite-oxidising bacteria were verified in water column samples through Most Probable Number (MPN) analysis, but they were not detected in sediment samples by FISH. Ammonia removal efficiencies occurred systematically along the ponds (24, 32, and 34% for polishing pond 1, 2, and 3, respectively) but the major reaction responsible for this removal is still unclear. Some nitrification might have occurred in water samples because some nitrifying bacteria were present. Also Anammox reaction might have occurred because Anammox genes were detected in the sediments, but probably this reaction was too low to be noticed. It is important also to consider that some of the ammonia removal observed might be related to NH3 stripping, associated with the pH increase resulting from the intensive photosynthetic activity in the ponds (mechanism under investigation). Therefore, it can be concluded that more than one mechanism (or reaction) might be involved in the ammonia removal in the polishing ponds investigated in this study.

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Liu, Bing, Ian Jarvis, Daisuke Naka, Rajeev Goel et Hidenari Yasui. « A benchmark simulation to verify an inhibition model on decay stage for nitrification ». Water Science and Technology 68, n^o 6 (1 septembre 2013) : 1242–50. http://dx.doi.org/10.2166/wst.2013.327.

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Activated Sludge Models (ASMs) are widely used for biological wastewater treatment plant design, optimisation and operation. In commonly used ASMs, the nitrification process is modelled as a one-step process. However, in some process configurations, it is desirable to model the concentration of nitrite nitrogen through a two-step nitrification process. In this study, the benchmark datasets published by the Water Environment Research Foundation (WERF) were used to develop a two-step nitrification model considering the kinetics of Ammonium Oxidising Bacteria (AOB) and Nitrite Oxidising Bacteria (NOB). The WERF datasets were collected from a chemostat reactor fed about 1,000 mg-NH3-N/L synthetic influent with at different sludge retention times of 20, 10 and 5-d, whereas the pH in the reactor varied in the range of 5.8 and 8.8. Supplemental laboratory batch experiments were conducted to assess the toxicity of nitrite-N on nitrifying bacteria. These tests suggested that 500 mg-N/L of nitrite at pH 7.3 was toxic to NOB and resulted in continuous decrease in bulk oxygen uptake rate. To model this phenomenon, a poisoning model was used instead of the traditional Haldane-type inhibition model. The poisoning model for NOB and AOB with different threshold poisonings for unionised NO2-N and NH3-N concentrations could successfully reproduce the three WERF datasets.

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Potter, Felicity Johnson, Ellen Bennett et Joseph T. Wiskich. « Effects of ageing and salicylate on beetroot mitochondria ». Functional Plant Biology 27, n^o 5 (2000) : 445. http://dx.doi.org/10.1071/pp99109.

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Root tissue slices of Beta vulgaris were aged by aerated mixing for 5 d in 0.1 mM CaSO4 solution with and without 0.5 mM salicylate (pH 7.0). Mitochondria, isolated from treated and fresh beetroot tissue, were investigated, and the activities of the NAD(P)H oxidising pathways of the mitochondrial inner and outer membranes, together with the activity of the alternative pathway, were measured. From these we determined which non-phosphorylating pathways of mitochondrial respiration were induced by the treatments. The presence of salicylate in the ageing treatment was shown to increase the activity of the alternative pathway as well as the level of alternative oxidase protein. This increase was above that seen in the ageing treatment alone. Investigation of the other non-phosphorylating pathways of mitochondrial respiration indicated that while they also increased during ageing, they were not specifically affected by salicylate treatment. The specific induction of the alternative pathway increased activity by almost 4-fold from the fresh tissue and 2-fold from the aged tissue rates.

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Rowan, A. K., G. Moser, N. Gray, J. R. Snape, D. Fearnside, T. P. Curtis, M. R. Barer et I. M. Head. « A comparitive study of ammonia-oxidizing bacteria in lab-scale industrial wastewater treatment reactors ». Water Science and Technology 48, n^o 3 (1 août 2003) : 17–24. http://dx.doi.org/10.2166/wst.2003.0149.

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The diversity and community structure of the b-proteobacterial ammonia oxidising bacteria (AOB) in a range of different lab-scale industrial wastewater treatment reactors were compared. Three of the reactors treat waste from mixed domestic and industrial sources whereas the other reactor treats waste solely of industrial origin. PCR with AOB selective primers was combined with denaturing gradient gel electrophoresis to allow comparative analysis of the dominant AOB populations and the phylogenetic affiliation of the dominant AOB was determined by cloning and sequencing or direct sequencing of bands excised from DGGE gels. Different AOB were found within and between different reactors. All AOB sequences identified were grouped within the genus Nitrosomonas. Within the lab-scale reactors there appeared to be selection for a low diversity of AOB and predominance of a single AOB population. Furthermore, the industrial input in both effluents apparently selected for salt tolerant AOB, most closely related to Nitrosococcus mobilis and Nitrosomonas halophila.

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Walawska, Anetta, Magdalena Olak-Kucharczyk, Anna Kaczmarek et Marcin H. Kudzin. « Environmentally Friendly Bleaching Process of the Cellulose Fibres Materials Using Ozone and Hydrogen Peroxide in the Gas Phase ». Materials 17, n^o 6 (15 mars 2024) : 1355. http://dx.doi.org/10.3390/ma17061355.

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The paper presents the new eco-friendly method of bleaching process of the cellulose fibre materials. Cellulose materials were bleached using hydrogen peroxide (both in aqueous solution, vapours, ozone and by the combined action of gaseous hydrogen peroxide and ozone. The method using hydrogen peroxide in aqueous solution presents the standard procedure and was used as the comparison technique. The bleaching processes using gaseous oxidants were carried out in a prototype device for dry, low-temperature treatment of fibrous materials with the use of oxidising agents in the gas phase. The influence of the innovative gas-phase bleaching method on the cotton samples’ properties was analysed by Scanning Electron Microscopy (SEM), evaluation of the colour and whiteness, assessment of the polymerisation degree (DP), analysis of the mechanical properties and sorption capacity as well as microbiological assessment against colonies of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The comparison of the obtained results led to the conclusion that the bleaching processes using gas-phase agents—vaporised hydrogen peroxide, ozone or their combination—are non-invasive. The applied bleaching processes resulted in a slightly lower whiteness parameters than standard bath bleaching. After the bleaching processes with ozone and vaporised hydrogen peroxide separately, the decrease in the DP and tensile strength was similar to that observed after the bleaching with aqueous H2O2. When both processes were used together, a higher reduction in DP and tensile strength was noticed. Both oxidising agents showed a strong biocidal effect against bacteria. Gas-phase bleaching procedures, due to the lower temperature (35 °C vs. 98 °C) and minimal water consumption, have economic and environmental advantages, which allows their use in semi-industrial applications. It has been shown that the treatment of cotton fabrics using ozone and hydrogen peroxide in the gas phase allows to simultaneously obtain the bleaching and disinfection effect.

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Rowan, A. K., J. R. Snape, D. Fearnside, T. P. Curtis, M. R. Barer et I. M. Head. « A comparison of autotrophic ammonia-oxidizing bacteria in full- and laboratory-scale wastewater treatment reactors ». Water Science and Technology 46, n^o 1-2 (1 juillet 2002) : 319–22. http://dx.doi.org/10.2166/wst.2002.0495.

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Lab-scale reactors are commonly used to simulate full-scale plants as they permit the effects of defined experimental perturbations to be evaluated. Ideally, lab- and full-scale reactors should possess similar microbial populations. To determine this we compared the diversity of the β-proteobacterial autotrophic ammonia-oxidising bacteria (AOB) in a full-scale and lab-scale biological aerated filter (BAF) using PCR with AOB selective primers combined with denaturing gradient gel electrophoresis (DGGE). PCR amplified 16S rRNA gene fragments from the nitrification unit of the lab-and full-scale BAF were subjected to cloning and sequencing to determine the phylogenetic affiliation of the AOB. A high degree of comparability between the lab-and full-scale BAF was observed with respect to AOB populations. However minor differences were apparent. The importance of these minor constituents in the overall performance of the reactor is unknown. Nonetheless the lab-scale reactor in this study did appear to reflect the dominant AOB community within the full-scale equivalent.

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Zhang, Qisen, L. Mischis et JT Wiskich. « Respiratory Responses of Pea and Wheat Seedlings to Chloramphenicol Treatment ». Functional Plant Biology 23, n^o 5 (1996) : 583. http://dx.doi.org/10.1071/pp9960583.

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A common feature in responding to chloramphenicol treatment for pea and wheat seedlings was the substantial increases in the rates of cyanide-resistant respiration. However, they were very different in many other aspects. Whole pea leaves appeared yellowish 3 or more days after chloramphenicol treatment. The chlorophyll content decreased by 30% after 9-10 days. In wheat seedlings, chloramphenicol treatment resulted in a complete loss of chlorophyll and formation of white tissues in the base of their leaves. The top region of leaves was still green. The un-inhibited rates of respiration decreased in pea, but increased in wheat mitochondria oxidising NADH. There was an approximately 5-fold increase in the activity of externally facing NADH dehydrogenase in wheat, but not in pea mitochondria. Western blot analysis showed that there were two additional bands of lower molecular weight alternative oxidases (32-33 kDa) in chloramphenicol-treated wheat leaf mitochondria, but there was no increase in alternative oxidase proteins in chloramphenicol-treated pea leaf and root mitochondria. Wheat seedlings responded to chlorarnphenicol treatment presumably by increasing the rate of glycolysis, while pea seedlings may have a different mechanism.

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Almeida, E., L. Fedrizzi et T. C. Diamantinio. « Oxidising alternative species to chromium VI in zinc-galvanised steel surface treatment. Part 2—An electrochemical study ». Surface and Coatings Technology 105, n^o 1-2 (juin 1998) : 97–101. http://dx.doi.org/10.1016/s0257-8972(98)00476-9.

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Chlup, Zdeněk, Martin Černý, Adam Strachota, Martina Halasova et Ivo Dlouhý. « Fibre-Matrix Interface Development during High Temperature Exposition of Long Fibre Reinforced SiOC Matrix ». Key Engineering Materials 592-593 (novembre 2013) : 401–4. http://dx.doi.org/10.4028/www.scientific.net/kem.592-593.401.

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The fracture behaviour of long fibre reinforced composites is predetermined mainly by properties of fibre-matrix interface. The matrix prepared by pyrolysis of polysiloxane resin possesses ability to resist high temperatures without significant damage under oxidising atmosphere. The application is therefore limited by fibres and possible changes in the fibre matrix interface. The study of development of interface during high temperature exposition is the main aim of this contribution. Application of various techniques as FIB, GIS, TEM, XRD allowed to monitor microstructural changes in the interface of selected places without additional damage caused by preparation. Additionally, it was possible to obtain information about damage, the crack formation, caused by the heat treatment from the fracture mechanics point of view.

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Zhang, Yun, Feng Liu, Yidong Lin, Lei Sun, Xinru Guo, Shuai Yang et Jinlong He. « Enhanced Swine Wastewater Treatment by Constructed Wetland—Microbial Fuel Cell Systems ». Water 14, n^o 23 (2 décembre 2022) : 3930. http://dx.doi.org/10.3390/w14233930.

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This paper studies the effects of planting plants and coupled microbial fuel cells (MFCs) on the decontamination capacity and purification mechanism of constructed wetlands (CWs). Four systems were set, namely CW-without plants (A1), CW-with plants (A2), CW-MFC-without plants (A3) and CW-MFC-with plants (A4). The daily reductions per unit area of chemical oxygen demand (COD) were 48.72 ± 5.42, 51.26 ± 4.10, 53.49 ± 5.44 and 58.54 ± 4.16 g·(d·m2)−1, respectively. The daily reductions per unit area of nitrogen (N) were 11.89 ± 0.73, 12.38 ± 0.76, 12.24 ± 0.79 and 13.61 ± 1.07 g·(d·m2)−1, respectively. After studying the pollutant removal efficiency, it was found that the unit area of A4 removes the highest number of pollutants, improving the area efficiency of the wetland system and fundamentally alleviating the disadvantage of the large land footprint of wetland processes. The average output voltages of A3 and A4 were 568.29 and 717.46 mV, respectively, and the maximum power densities were 4.59 and 15.87 mW/m3, respectively. In addition, after high-throughput analysis of microbial samples, anaerobic ammonia oxidising (anammox) bacteria were found to remove N from the system in the anaerobic anode region.

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Ma, Qingyi. « Application Of Advanced Oxidation Process Based on Ozone in Water Treatment ». Highlights in Science, Engineering and Technology 96 (5 mai 2024) : 139–43. http://dx.doi.org/10.54097/5cnrfy90.

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Wastewater treatment is an effective way to address water scarcity. Advanced oxidation processes (AOPs) are a wastewater treatment technology that is currently attracting a lot of attention, and it is a technology that uses physical or chemical pathways such as ozone, ultraviolet light, and the Fenton reaction to generate free radicals and then treats pathogens and organic pollutants by oxidation of the free radicals.Ozone is very strong oxidising agent and it has a powerful ability to break down wide range of organic and inorganic pollutants. However its usage in the wastewater treatment is still not very popular due to several drawbacks it posses, as it not possible to achieve the goal of wastewater treatment by ozone alone due to its mass transfer limitations, slow reaction rates, non specific for certain under low reaction rates pollutants select,may costs relatively higher thanother treatment processes etc. By combining ozone with H2O2, UV light, and catalysts, the efficiency of the wastewater treatment process will be increased because it will help make more hydroxyl radicals. This review discusses various ozone-based AOPs such as ozone/UV, ozone/hydrogen peroxide, and catalytic ozonation, focusing on their mechanisms and applications in wastewater treatment.

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Park, G., M. Yu, J. Go, E. Kim et H. Kim. « Comparison between ozone and ferrate in oxidising geosmin and 2-MIB in water ». Water Science and Technology 55, n^o 5 (1 mars 2007) : 117–25. http://dx.doi.org/10.2166/wst.2007.170.

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Among the chemicals causing taste and odour (T&O) in drinking water, the most commonly identified and problematic ones are geosmin and 2-MIB (2-methylisoborneol). Since the reported odour thresholds of geosmin and 2-MIB are as low as 4 and 8.5 ng/L, respectively, they are not readily removed by conventional water treatment processes. In this study, ozone (O3) and ferrate (Fe(VI)) were applied to oxidise geosmin and 2-MIB. Their performances were compared in terms of removal efficiency of geosmin and 2-MIB. In the case of O3, removal efficiency of geosmin and 2-MIB ozonation at different initial O3 doses, H2O2/O3 ratios and water temperatures were evaluated. The oxidation rates of geosmin and 2-MIB by Fe(VI) were measured within pH 6–8. The effect of H2O2 addition was also evaluated. In summary, O3, especially with H2O2, could almost completely oxidise geosmin and 2-MIB, while Fe(VI) could not oxidise them more than 25% at any pH that was considered in this study. This was attributed to the structure of the organics and high reaction selectivity of Fe(VI). Further study should be conducted to find the reason of inhibition of oxidation by Fe(VI).

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Tarre, S., E. Shlafman, M. Beliavski et M. Green. « Changes in ammonia oxidiser population during transition to low pH in a biofilm reactor starting with Nitrosomonas europaea ». Water Science and Technology 55, n^o 8-9 (1 avril 2007) : 363–68. http://dx.doi.org/10.2166/wst.2007.278.

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Recent experiments in our laboratory using both biofilm and suspended biomass reactors have demonstrated high rate nitrification at low pH with known autotrophic nitrifying bacteria originating from wastewater treatment plants refuting previous assumptions that nitrification is significantly inhibited at low pH. Since much of the earlier microbiological work regarding ammonia oxidising bacteria (AOB) physiology was carried out using Nitrosomonas europaea, this model bacterium's capability for high rate nitrification at low pH in a continuous biofilm reactor was tested. A biofilm reactor filled with sintered glass particles was inoculated with a pure culture of N. europaea. The reactor was first operated to high nitrification rates under conditions favourable to N. europaea (pH > 7; high ammonium concentrations). To eliminate inhibitory concentrations of nitrite at low pH, an enriched culture of Nitrospira (a nitrite oxidising bacterium) was then added. The transition from neutral to acidic conditions was attempted by sharply lowering the nitrification rate and by using a feeding solution containing insufficient buffer for complete nitrification. As opposed to other successful transitions, the pH in the N. europaea/Nitrospira reactor initially dropped only slightly and maintained pH > 6 for over two weeks. The reactor reached pH 4.5 only after four weeks. FISH results showed that while the percent of AOB and Nitrospira to eubacteria remained relatively constant at 51.1±8.2% and 40.8±6.4%, respectively, the AOB community changed completely in 60 days from 100% N. europaea to 100% Nitrosomonas oligotropha. Even though N. oligotropha was not intentionally introduced into the reactor, it is apparently much better adapted to conditions of low pH.

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Sozarukova, Madina M., Elena V. Proskurnina, Ekaterina M. Kochneva, Andrey K. Barinov, Alexander E. Baranchikov et Vladimir K. Ivanov. « A New Chemiluminescence Assay for Hypochlorite Detection in Water : A Synergistic Combination of WS2 Quantum Dots and Luminol ». Water 16, n^o 21 (24 octobre 2024) : 3044. http://dx.doi.org/10.3390/w16213044.

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The issue of the qualitative and quantitative analysis of the concentration of oxidising species in aquatic environments is crucial for a wide range of biological and environmental tasks. In particular, reactive chlorine species, specifically hypochlorite (ClO−), play a significant biochemical role in the operation of the immune system. There is also the challenge of determining the presence of ClO− in purified drinking water that is supplied by water treatment systems. Traditional chemical analytical methods often lack the required selectivity and sensitivity to detect oxidising compounds, and chemiluminescence-based techniques offer an alternative solution. In this study, we propose a simple and selective approach for the chemiluminescent detection of hypochlorite in aqueous media under neutral conditions. The technique is based on measuring a chemiluminescent signal generated in the presence of hypochlorite by a combined probe comprising commercially available WS2 quantum dots and luminol. The oxidation of WS2 with hypochlorite followed by a reaction with luminol results in an intense luminescent signal that enables the selective determination of hypochlorite under neutral conditions. The greatest sensitivity with this method was achieved when combining WS2 quantum dots with L-012, a highly sensitive analogue of luminol. Additionally, the use of L-012 improved the detection limit for hypochlorite to 2 × 10−6 M. Due to its selectivity in determining hypochlorite in the presence of reactive oxygen species (hydrogen peroxide) under neutral conditions with high sensitivity and with a wide linear range, the proposed approach provides an attractive analytical tool for the analysis of water samples and biological liquids.

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Shetty, Raviraj, Adithya Hegde, Uday Kumar Shetty SV, Rajesh Nayak, Nithesh Naik et Madhukar Nayak. « Processing and Mechanical Characterisation of Titanium Metal Matrix Composites : A Literature Review ». Journal of Composites Science 6, n^o 12 (14 décembre 2022) : 388. http://dx.doi.org/10.3390/jcs6120388.

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Today, Discontinuously Reinforced Particulate Titanium Matrix Composites (DRPTMCs) have been the most popular and challenging in consideration with development and heat treatment due to their significant weight-saving capacity, high specific strength, stiffness and oxidising nature compared with other metals and alloys. Owing to their excellent capabilities, DRPTMCs are widely used in aerospace, automobiles, biomedical and other industries. However, regardless of the reinforcements, such as continuous fibres or discontinuous particulates, the unique properties of DRPTMCs have dealt with these composites for widespread research and progress around the domain. Even though DRPTMCs are one of the most studied materials, expedient information about their properties, processing, characterisation and heat treatment is still scattered in the literature. Hence, this paper focuses on a literature review that covers important research work that has led to advances in DRPTMCs material systems. Further, this paper also deals with broad details about the particulates, manufacturing processes and heat treatment processes.

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Gustavsson, D. J. I., et J. la Cour Jansen. « Dynamics of nitrogen oxides emission from a full-scale sludge liquor treatment plant with nitritation ». Water Science and Technology 63, n^o 12 (1 juin 2011) : 2838–45. http://dx.doi.org/10.2166/wst.2011.487.

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Biological treatment in wastewater treatment plants (WWTPs) is a source of nitrogen oxides (N2O, NO and NO2) emitted to the atmosphere. Aerobic ammonia-oxidising bacteria (AOB) have been suggested to be the main source of these emissions. In a full-scale sludge liquor treatment plant at Sjölunda WWTP, it was shown that significant emissions of N2O, NO and NO2 do occur. The plant is operated with nitritation alone, which gives an environment enriched in aerobic AOB. During normal operation, emissions of N2O, NO and NO2 were found to be 3.8%, 0.06% and 0.01% of the ammonium nitrogen load. The N2O emissions were larger than the recommended estimated figure of the Intergovernmental Panel on Climate Change (IPCC) for a complete wastewater treatment plant. The N2O emissions correlated positively with the length of the previous anoxic period, i.e., settling and decantation, and with the ammonium oxidation rate. The NO and NO2 emission profiles were similar and dependent on ammonium oxidation and DO level, but the NO2 concentrations were always lower.

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Yabalak, Erdal, Özkan Görmez et Belgin Sönmez. « Degradation, dephenolisation and dearomatisation of olive mill wastewater by subcritical water oxidation method using hydrogen peroxide : Application of multi-response central composite design ». Journal of the Serbian Chemical Society 83, n^o 4 (2018) : 489–502. http://dx.doi.org/10.2298/jsc170909113y.

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An environmentally friendly method to decontaminate the olive mill wastewater, which is encountered as a major environmental problem is presented in this study. The removal of both polyphenolic and aromatic content and the degradation of wastewater of olive mill supplied from Mersin/Turkey region were investigated by the subcritical water oxidation method using H2O2. The central composite design of response surface methodology was used to assess the effects of temperature, treatment time, and the concentration of oxidising agent. The reliability of the employed method was proved by ANOVA. The optimum experimental parameters were determined and theoretical equations were proposed in each case. The highest chemical oxygen demand removal, dephenolisation and dearomatisation values were obtained as 85.74, 96.13 and 95.94 %, respectively.

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Ishak, M. A. M., K. Ismail, M. A. M. Nawi et A. F. Ismail. « CHEMICAL DESULPHURISATION OF SUB-BITUMINOUS HIGH SULPHUR INDONESIAN COAL VIA PEROXYACETIC ACID TREATMENT ». ASEAN Journal on Science and Technology for Development 20, n^o 1 (21 décembre 2017) : 27–36. http://dx.doi.org/10.29037/ajstd.366.

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The chemical desulphurisation from an Indonesian high sulphur sub-bituminous Banjarmasin Haji Ali-Aliansar coal was investigated using the peroxyacetic acid (PAA), a mild oxidising agent. A mixture of hydrogen peroxide:acetic acid (i.e. 30:70 by volume ratio with 6% of hydrogen peroxide concentration) at 50°C of reaction temperature is capable of reducing the total sulphur content in the coal from 3.46% to 1.29% by weight, corresponding to the removal of up to ca. 72% of the total sulphur; both the inorganic (mainly pyrite) and organic sulphur forms, and approximately 10 to 44% of ashes in the coal. The simultaneous removal of both inorganic and organic sulphur forms was measured with respect to reagent volume mixed ratio, reaction temperature and hydrogen peroxide concentrations. The success of desulphurisation was measured by the reduction of the total sulphur content of the desulphurised product, its S/ C atomic ratios and ash yields of the treated coal. In general, all inorganic and some of the organic sulphur could be removed from the coal using mild conditions without severely affecting the coal microstructure as observed via the Scanning Electron Microscope with Energy Dispersive X-ray (SEM-EDX) which supplied the coal sample.

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Freidman, Benjamin L., Kathy A. Northcott, Peta Thiel, Sally L. Gras, Ian Snape, Geoff W. Stevens et Kathryn A. Mumford. « From urban municipalities to polar bioremediation : the characterisation and contribution of biogenic minerals for water treatment ». Journal of Water and Health 15, n^o 3 (10 février 2017) : 385–401. http://dx.doi.org/10.2166/wh.2017.019.

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Minerals of biological origin have shown significant potential for the separation of contaminants from water worldwide. This study details the contribution of biologically derived minerals to water treatment operations, with a focus on filtration media from urban municipalities and remote cold regions. The results support biofilm-embedded iron and manganese to be the building blocks of biogenic mineral development on activated carbon and nutrient-amended zeolites. The presence of similar iron and manganese oxidising bacterial species across all filter media supports the analogous morphologies of biogenic minerals between sites and suggests that biological water treatment processes may be feasible across a range of climates. This is the first time the stages of biogenic mineral formation have been aligned with comprehensive imaging of the biofilm community and bacterial identification; especially with respect to cold regions. Where biogenic mineral formation occurs on filter media, the potential exists for enhanced adsorption for a range of organic and inorganic contaminants and improved longevity of filter media beyond the adsorption or exchange capacities of the raw material.

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Rowan, Arlene K., Jason R. Snape, David Fearnside, Michael R. Barer, Thomas P. Curtis et Ian M. Head. « Composition and diversity of ammonia-oxidising bacterial communities in wastewater treatment reactors of different design treating identical wastewater ». FEMS Microbiology Ecology 43, n^o 2 (mars 2003) : 195–206. http://dx.doi.org/10.1111/j.1574-6941.2003.tb01059.x.

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