Search results for "Gradation"
showing 10 items of 1275 documents
Experimental Investigation for Degradation Analysis of an RC Italian Viaduct and Retrofitting Design
2020
AbstractThe degradation state of RC bridge structures is one of the most important and difficult aspects to be interpreted. For these structures, structural analysis using FEM requires a reliable d...
Performance of a pilot-scale biotrickling filter in controlling the volatile organic compound emissions in a furniture manufacturing facility.
2009
A 0.75-m3 pilot-scale biotrickling filter was run for over 1 yr in a Spanish furniture company to evaluate its performance in the removal of volatile organic compounds (VOCs) contained in the emission of two different paint spray booths. The first one was an open front booth used to manually paint furniture, and the second focus was an automatically operated closed booth operated to paint pieces of furniture. In both cases, the VOC emissions were very irregular, with rapid and extreme fluctuations. The pilot plant was operated at an empty bed residence time (EBRT) ranging from 10 to 40 sec, and good removal efficiencies of VOCs were usually obtained. When a buffering activated carbon prefil…
The interdisciplinary nature of <i>SOIL</i>
2015
Abstract. The holistic study of soils requires an interdisciplinary approach involving biologists, chemists, geologists, and physicists, amongst others, something that has been true from the earliest days of the field. In more recent years this list has grown to include anthropologists, economists, engineers, medical professionals, military professionals, sociologists, and even artists. This approach has been strengthened and reinforced as current research continues to use experts trained in both soil science and related fields and by the wide array of issues impacting the world that require an in-depth understanding of soils. Of fundamental importance amongst these issues are biodiversity,…
Photoelectrocatalyzed degradation of a pesticides mixture solution (chlorfenvinphos and bromacil) by WO3 nanosheets
2019
[EN] A photoelectrocatalyst consisting of WO3 nanosheets or nanorods has been synthesized by electrochemical anodization under hydrodynamic conditions, and has been used for the degradation of two toxic pesticides: chlorfenvinphos and bromacil. Nanostructures have been characterized by FESEM and Raman spectroscopy. Photoelectrochemical degradation tests have been carried out both for individual pesticide solutions and for a mixture solution, and the concentration evolution with time has been followed by UV¿Vis spectrophotometry. For individual pesticides, pseudo-first order kinetic coefficients of 0.402 h¿1 and 0.324 h¿1 have been obtained for chlorfenvinphos and bromacil, respectively, whi…
Multi O- and S-isotopes as tracers of black crusts formation under volcanic and non-volcanic atmospheric conditions in Sicily (Italy)
2020
International audience; The deterioration of monument or building stone materials is mostly due to the growth of black crusts that cause blackening and disaggregation of the exposed surface. This study reports on new oxygen (δ17O, δ18O and Δ17O) and sulphur (δ33S, δ34S, δ36S, Δ33S and Δ36S) isotopic analyses of black crust sulphates formed on building stones in Sicily (Southern Italy). The measurements are used to identify the possible influence of volcanic emissions on black crust formation. Black crusts were mostly sampled on carbonate stone substrate in different locations subject to various sulphur emission sources (marine, anthropogenic and volcanic). Unlike atmospheric sulphate aeroso…
EFFICIENT DEGRADATION OF CLOFIBRIC ACID BY HETEROGENEOUS PHOTOCATALYTIC OXIDATION PROCESS
2019
International audience; Emerging pollutants such as pharmaceutical active compounds were detected worldwide in different environmental compartments. Nowadays, multiple studies are focused on the investigation of their environmental fate, as well as to find new, efficient and sustainable removal technologies. Several studies demonstrated that heterogeneous photocatalysis is one of the most promising techniques used for water purification. Thus, the aim of our work was to evaluate the photodegradation efficiency of a refractory emergent compound, named clofibric acid, under UV light in aqueous solution. We report that photodegradation and mineralization efficiency are strongly dependent of th…
Unveiling the distinctive role of titanium dioxide nanoparticles in aerobic sludge digestion.
2022
Abstract Aerobic digestion is considered to be a common process for the stabilization of waste activated sludge (WAS) in the small-sized wastewater treatment systems, while the broad application of titanium dioxide nanoparticles (TiO2 NPs) results in their unavoidable existence in WAS aerobic digestion, with its role in aerobic sludge digestion being never documented. This study set up a series of aerobic sludge digesters to evaluate the previously unknown role of TiO2 NPs on the performance of the digesters. The volatile solids (VS) degradation percentage increased from 21.9 ± 0.6% to 26.9 ± 0.1% − 30.0 ± 0.3% with the different contents of TiO2 NPs (0, 1, 20 and 50 mg/L). Similarly, the t…
Fate of endocrine disruptor compounds in an anaerobic membrane bioreactor (AnMBR) coupled to an activated sludge reactor
2018
[EN] The occurrence and fate of three groups of micropollutants - alkylphenols, pentachlorophenol and hormones - were studied in a pilot plant consisting of an anaerobic membrane bioreactor (AnMBR) coupled to an activated sludge reactor (University of Cape Town configuration - UCT). Under anaerobic conditions, the octylphenol and technical-nonylphenol soluble concentrations increased producing negative degradation ratios (i.e., -175 and -118%, respectively). However, high 4-n-nonylphenol and bisphenol-A degradation ratios (92 and 59% for 4-n-nonylphenol and bisphenol-A, respectively) as well as complete pentachlorophenol, estrone, 17 beta-estradiol and 17 alpha-ethinylestradiol removal were…
Removal and fate of endocrine disruptors chemicals under lab-scalepostreatment stage. Removal assessment using light, oxygen and microalgae
2013
[EN] The aim of this study was to assess the effect of light, oxygen and microalgae on micropollutants removal. The studied micropollutants were 4-(1,1,3,3-tetramethylbutyl)phenol (OP), technical-nonylphenol (t-NP), 4-n-nonylphenol (4-NP), Bisphenol-A (BPA). In order to study the effect of the three variables on the micropollutants removal, a factorial design was developed. The experiments were carried out in four batch reactors which treated the effluent of an anaerobic membrane bioreactor. The gas chromatography mass spectrometry was used for the measurement of the micropollutants. The results showed that light, oxygen and microalgae affected differently to the degradation ratios of each …
Aerobic moving bed biofilm reactor treating thermomechanical pulping whitewater under thermophilic conditions.
2002
The continuously operated laboratory scale Kaldnes moving bed biofilm reactor (MBBR) was used for thermophilic (55 degrees C) aerobic treatment of TMP whitewater. In the MBBR, the biomass is grown on carrier elements that move along with the water in the reactor. Inoculation with mesophilic activated sludge gave 60-65% SCOD removal from the first day onwards. During the 107 days of experiment, the 60-65% SCOD removals were achieved at organic loading rates of 2.5-3.5 kg SCODm(-3) d(-1), the highest loading rates applied during the run and HRT of 13-22h. Carbohydrates, which contributed to 50-60% of the influent SCOD. were removed by 90-95%, while less than 15% of the lignin-like material (3…