Search results for "Retention time"
showing 10 items of 71 documents
Combination of the OSA process with thermal treatment at moderate temperature for excess sludge minimization
2019
Abstract This study investigated the chance to couple the conventional Oxic Settling Anaerobic (OSA) process with a thermic treatment at moderate temperature (35 °C). The maximum excess sludge reduction rate (80%) was achieved when the plant was operated under 3 h of hydraulic retention time (HRT). Compared with the conventional OSA system, the thermic treatment enabled a further improvement in excess sludge minimization of 35%. The observed yield coefficient decreased from 0.25 gTSS gCOD−1 to 0.10 gTSS gCOD−1 when the temperature in the anaerobic reactor was increased to 35 °C, despite the lower HRT (3 h vs 6 h). Moreover, the thermic treatment enabled the decrease of filamentous bacteria,…
Performance of a membrane-coupled high-rate algal pond for urban wastewater treatment at demonstration scale
2020
[EN] The objective of this study was to evaluate the performance of an outdoor membrane-coupled high-rate algal pond equipped with industrial-scale membranes for treating urban wastewater. Decoupling biomass retention time (BRT) and hydraulic retention time (HRT) by membrane filtration resulted in improved process efficiencies, with higher biomass productivities and nutrient removal rates when operating at low HRTs. At 6 days of BRT, biomass productivity increased from 30 to 66 and to 95 g.m(-3).d(-1) when operating at HRTs of 6, 4 and 2.5 days, respectively. The corresponding nitrogen removal rates were 4, 8 and 11 g N.m(-3).d(-1) and the phosphorous removal rates were 0.5, 1.3 and 1.6 g P…
Understanding the performance of an AnMBR treating urban wastewater and food waste via model simulation and characterization of the microbial populat…
2018
[EN] An anaerobic membrane bioreactor (AnMBR) pilot plant treating kitchen food waste (FW) jointly with urban wastewater was run for 536 days. Different operational conditions were tested varying the sludge retention time (SRT), the hydraulic retention time (HRT) and the penetration factor (PF) of food waste disposers. COD removal efficiency exceeded 90% in all tested conditions. The joint treatment resulted in an almost 3-fold increase in methane production (at 70 days of SRT, 24 h HRT and 80% PF) in comparison with the treatment of urban wastewater only. Mathematical model simulations and Illumina technology were used to obtain in-depth information of this outstanding process performance.…
A multicentric study to evaluate the use of relative retention times in targeted proteomics.
2016
Despite the maturity reached by targeted proteomic strategies, reliable and standardized protocols are urgently needed to enhance reproducibility among different laboratories and analytical platforms, facilitating a more widespread use in biomedical research. To achieve this goal, the use of dimensionless relative retention times (iRT), defined on the basis of peptide standard retention times (RT), has lately emerged as a powerful tool. The robustness, reproducibility and utility of this strategy were examined for the first time in a multicentric setting, involving 28 laboratories that included 24 of the Spanish network of proteomics laboratories (ProteoRed-ISCIII). According to the results…
Optimisation of gradient elution with serially-coupled columns. Part I: single linear gradients.
2014
A mixture of compounds often cannot be resolved with a single chromatographic column, but the analysis can be successful using columns of different nature, serially combined through zero-dead volume junctions. In previous work (JCA 1281 (2013) 94), we developed an isocratic approach that optimised simultaneously the mobile phase composition, stationary phase nature and column length. In this work, we take the challenge of implementing optimal linear gradients for serial columns to decrease the analysis time for compounds covering a wide polarity range. For this purpose, five ACE columns of different selectivity (three C18 columns of different characteristics, a cyano and a phenyl column) we…
Wide-range screening of banned veterinary drugs in urine by ultra high liquid chromatography coupled to high-resolution mass spectrometry
2012
In this work, an ultra high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) methodology is proposed for the multi-class multi-residue screening of banned and unauthorized veterinary drugs in bovine urine, using an Orbitrap Exactive™ analyzer working at a resolving power of 50,000 FWHM in full scan, both in positive and negative mode. The method currently covers 87 analytes belonging to different families such as steroid hormones, β-agonists, resorcylic acid lactones (RAL), stilbens, tranquillizers, nitroimidazoles, corticosteroids, NSAIDs, amphenicoles, thyreostatics and other substances such as dapsone. A database including the elemental composition, the po…
Gas-liquid chromatographic analyses
1983
Abstract The gas chromatography of mixtures of n -alkyl acetates (CH 3 COOR, R = C 1 —C 8 ) and methyl esters of aliphatic n -carboxylic acids (R′COOCH 3 , R′ = C 1 —C 8 ) and certain of their monochlorinated derivatives has been studied on Carbowax 20M and SE-30 glass capillary columns under the same operating conditions. The separation of the isomeric monochlorinated esters was complete on Carbowax 20M, whereas on SE-30 the peaks of 6- and 7-chlorooctyl acetates and methyl (ω − 1)- and (ω − 2)-chlorooctanoates and -nonanoates partly overlapped. The complete separation of the mixtures could not be achieved, however, on Carbowax 20M, in spite of the use of various operating conditions. The …
Biological nitrogen removal from landfill leachate: a pilot-scale study
1999
A pilot-scale two-stage process including an anaerobic pretreatment (up-flow anaerobic sludge blanket, UASB) unit and a pre-denitrification activated sludge process was studied for treating leachates from a municipal landfill (waste aged 4 to 5 years, area 2.5 ha) and from a windrow composting area (1ha). A single-stage pilot process was used for nitrification studies. The leachate characteristics were as follows: COD 740 to 2400 mg 1-1 (chemical oxygen demand), BOD7 (biochemical oxygen demand) approximately 1000 mg 1 -1, Ntot 40 to 120 mg 1-1 and the temperature was between 2 and 21°C. The results show that 45 to 50% COD removal could be achieved in the UASB reactor even at temperatures b…
Design methodology for submerged anaerobic membrane bioreactors (AnMBR): A case study
2015
[EN] The main objective of this study is to propose guidelines for designing submerged anaerobic MBR (AnMBR) technology for municipal wastewater treatment. The design methodology was devised on the basis of simulation and experimental results from an AnMBR plant featuring industrial-scale hollow-fibre membranes. The proposed methodology aims to minimise both capital expenditure and operating expenses, and the key parameters considered were: hydraulic retention time, solids retention time, mixed liquor suspended solids concentration in the membrane tank, 20 C-standardised critical flux, specificgas demand per square metre of membrane area, and flow of sludge being recycled from the membrane …
New insights in the metabolic behaviour of PAO under negligible poly-P reserves
2017
[EN] In a previous study the authors confirmed the ability of PAOs to perform GAO metabolism in short-term experiments. However, what happens when PAOs are exposed to poly-P shortage for an extended period of time? The answer to this question was the aim of this work from a macroscopic and microscopic point of view. Therefore, the poly-P was removed from a PAO enriched SBR and maintained without poly-P during five solid retention time. The PAOs were found to quickly change their metabolism to a clear GAO performance and remained without GAO colonization for the entire experimental period, even though GAO was present (around 5%) at the beginning of the experiment. Unlike the results obtained…