Search results for " Paper"
showing 10 items of 1695 documents
Exploring the limits of anaerobic biodegradability of urban wastewater by AnMBR technology
2018
[EN] Anaerobic membrane bioreactors (AnMBRs) can achieve maximum energy recovery from urban wastewater (UWW) by converting influent COD into methane. The aim of this study was to assess the anaerobic biodegradability limits of urban wastewater with AnMBR technology by studying the possible degradation of the organic matter considered as non-biodegradable as observed in aerobic membrane bioreactors operated at very high sludge retention times. For this, the results obtained in an AnMBR pilot plant operated at very high SRT (140 days) treating sulfate-rich urban wastewater were compared with those previously obtained with the system operating at lower SRT (29 to 70 days). At 140 days SRT the …
Extreme thermophilic (70°C), VFA-fed UASB reactor: performance, temperature response, load potential and comparison with 35 and 55°C UASB reactors
1999
Abstract The paper evaluates the reactor performance, load potential and temperature response of a 70°C, VFAs-fed UASB reactor, seeded with mesophilic granular sludge. Batch experiments were, in addition, conducted to assess the effect of temperature on the achievable residual VFAs in the 70°C effluent. The performance of similarly-fed and seeded 35 and 55°C UASB reactors was also tested. At a short HRT (2–3 h) and a moderate VLR of 12–20 g COD l−1 d−1, the 70°C UASB achieved 66–74% VFAs removal (acetate and butyrate 84–90%, propionate
Design of nutrient removal activated sludge systems
2003
A mechanistic mathematical model for nutrient and organic matter removal was used to describe the behavior of a nitrification denitrification enhanced biological phosphorus removal (NDEBPR) system. This model was implemented in a user-friendly software DESASS (design and simulation of activated sludge systems). A 484-L pilot plant was operated to verify the model results. The pilot plant was operated for three years over three different sludge ages. The validity of the model was confirmed with data from the pilot plant. Also, the utility of DESASS as a valuable tool for designing NDEBPR systems was confirmed.
Biofiltration of ethylbenzene vapours: influence of the packing material.
2006
In order to investigate suitable packing materials, a soil amendment composed of granular high mineralized peat (35% organic content) locally available has been evaluated as carrier material for biofiltration of volatile organic compounds in air by comparison with a fibrous peat (95% organic content). Both supports were tested to eliminate ethylbenzene from air streams in laboratory-scale reactors inoculated with a two-month conditioned culture. In pseudo-steady state operation, experiments at various ethylbenzene inlet loads (ILs) were carried out. Maximum elimination capacity of about 120 g m(-3) h(-1) for an IL of 135 g m(-3) h(-1) was obtained for the fibrous peat. The soil amendment re…
Tribenzylammonium chloride
2014
Single crystals of the title salt, C21H21NH+·Cl−, were isolated as a side product from the reaction involving [(C6H5CH2)3NH]2[HPO4] and Sn(CH3)3Cl in ethanol. Both the cation and the anion are situated on a threefold rotation axis. The central N atom in the cation has a slightly distorted tetrahedral environment, with angles ranging from 107.7 to 111.16 (10)°. In the crystal, the tribenzylammonium cations and chloride anions are linked through N—H...Cl and C—H...Cl hydrogen bonds, leading to the formation of infinite chains along [001]. The crystal studied was a merohedral twin.
Metal‐Free Electrochemical Synthesis of Sulfonamides Directly from (Hetero)arenes, SO2, and Amines
2021
Abstract Sulfonamides are among the most important chemical motifs in pharmaceuticals and agrochemicals. However, there is no methodology to directly introduce the sulfonamide group to a non‐prefunctionalized aromatic compound. Herein, we present the first dehydrogenative electrochemical sulfonamide synthesis protocol by exploiting the inherent reactivity of (hetero)arenes in a highly convergent reaction with SO2 and amines via amidosulfinate intermediate. The amidosulfinate serves a dual role as reactant and supporting electrolyte. Direct anodic oxidation of the aromatic compound triggers the reaction, followed by nucleophilic attack of the amidosulfinate. Boron‐doped diamond (BDD) electro…
Properties and interactions – melting point of tribromobenzene isomers
2021
The melting points of tribromobenzene isomers are correlated with the number, nature and distribution of intermolecular interactions in their structures.
2-(Mesitylmethylsulfanyl)pyridineN-oxide–18-crown-6 (2/1)
2008
In the title compound, 2C(15)H(17)NOS·C(12)H(24)O(6), the asymmetric unit consists of one N-oxide derivative and one-half of the 18-crown-6 ether, which lies on an inversion centre. In the crown ether, the O-C-C-O torsion angles indicate a gauche conformation of the ethyl-eneoxy units, while the C-O-C-C torsion angles indicate planarity of these segments. In the N-oxide unit, the dihedral angle between the pyridine and benzene rings is 85.88 (12)°. The crystal packing is stabilized by weak C-H⋯O hydrogen bonds and C-H⋯π inter-actions.
(S,S,S,S)-Nebivolol hydro-chloride hemihydrate.
2012
The asymmetric unit of the title hydrated salt, C22H26F2NO4+·Cl−·0.5H2O, consists of an (S,S,S,S)-nebivolol {nebivol = bis[2-(6-fluoro-3,4-dihydro-2H-1-benzopyran-2-yl)-2-hydroxyethyl]ammonium} cation, a chloride anion and a half-occupancy water molecule. The dihedral angle between the mean planes of the benzene rings is 50.34 (12)°. The pyran rings adopt half-chair conformations. The crystal packing features O—H...O hydrogen bonds and weak N—H...Cl, O—H...Cl, and O—H...Cl interactions, producing layers along (010).
5-Amino-1-phenyl-3-trifluoromethyl-1H-pyrazole-4-carboxylic acid
2009
In the title compound, C11H8F3N3O2, there are two molecules in the asymmetric unit wherein the phenyl rings make dihedral angles of 65.3 (2) and 85.6 (2)° with the pyrazole rings. In the crystal, pairs of molecules are held together by O—H...O hydrogen bonds between the carboxyl groups, forming a centrosymmetric dimer with an R22(8) motif. Intramolecular N—H...O interactions are also present.