951 resultados para waste water sludge
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"Authors: James J. Janssen and S. Alan Keller." -- Bibliographic data sheet.
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"HWRIC TR-012."
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"HWRIC RR-025."
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"HWRIC project HWR 86-010."
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"This report was prepared under a contract with the Illinois Dept. of Nuclear Safety (IDNS) in support of the Illinois Low-Level Radioactive Waste Task Group. Numerous staff members of the Illinois State Geological Survey (ISGS) and the Illinois State Water Survey (ISWS) contributed to this report, which was compiled under the general administrative direction of Bill Shilts and Derek Winstanley, Chiefs of the ISGS and ISWS, respectively."--P. iv.
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"HWRIC Project 88-045."
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"November 17, 1992-Bennington, VT"--Pt. 2.
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"A report on a conference at Zion, Illinois, which was supported by the Research Applications Directorate of the National Science Foundations, grant GI-30971".
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"Federal Water Quality Administration. Department of the Interior. B-166506."
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Rhizopus arrhizus, strain DAR 36017, produced L(+)-lactic acid in a simultaneous saccharification and fermentation process using starch waste effluents. Lactic acid at 19.5 - 44.3 g l(-1) with a yield of 0.85 - 0.96 g g(-1) was produced in 40 h using 20 - 60 g starch l(-1). Supplementation of nitrogen source may be unnecessary if potato or corn starch waste effluent was used as a production medium.
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The aim of this paper is to investigate the effect of shear history on activated sludge flocculation dynamics and to model the observed relationships using population balances. Activated sludge flocs are exposed to dramatic changes in the shear rate within the treatment process, as they pass through localised high and low mixing intensities within the aeration basin and are cycled through the different unit operations of the treatment process. We will show that shear history is a key factor in determining floc size, and that the floc size varies irreversibly with changes in shear rate. A population balance model of the flocculation process is also introduced and evaluated.
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The 23S rRNA-targeted probes GAM42a and BET42a provided equivocal results with the uncultured gammaproteobacterium 'Candidatus Competibacter phosphatis' where some cells bound GAM42a and other cells bound BET42a in fluorescence in situ hybridization (FISH) experiments. Probes GAM42a and BET42a span positions 1027-1043 in the 23S rRNAand differ from each other by one nucleotide at position 1033. Clone libraries were prepared from PCR products spanning the 16S rRNA genes, intergenic spacer region and 23S rRNA genes from two mixed cultures enriched in 'Candidatus C. phosphatis'. With individual clone inserts, the 16S rDNA portion was used to confirm the source organism as 'Candidatus C. phosphatis' and the 23S rDNA portion was used to determine the sequence of the GAM42a/BET42a probe target region. Of the 19 clones sequenced, 8 had the GAM42a probe target (T at position 1033) and 11 had G at position 1033, the only mismatch with GAM42a. However, none of the clones had the BET42a probe target (A at 1033). Non-canonical base-pairing between the 23S rRNA of 'Candidatus C. phosphatis' with G at position 1033 and GAM42a (G-A) or BET42a (G-T) is likely to explain the probing anomalies. A probe (GAM42_C1033) was optimized for use in FISH, targeting cells with G at position 1033, and was found to highlight not only some 'Candidatus C. phosphatis' cells, but also other bacteria. This demonstrates that there are bacteria in addition to 'Candidatus C. phosphatis' with the GAM42_C1033 probe target and not the BET42a or GAM42a probe target.
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The sheathed filamentous bacterium known as strain CT3, isolated by micromanipulation from an activated sludge treatment plant in Italy, is a member of the genus Thiothrix in the gamma-Proteobacteria according to 16S rDNA sequence analysis. The closest phylogenetic neighbours of strain CT3 are strains I and Q(T), which were also isolated from activated sludge and belong to the species Thiothrix fructosivorans. These strains have respectively 99.2 and 99.4 % similarity to CT3 by 16S rDNA sequence comparison. CT3 shows 63-67 % DNA-DNA hybridization with strain I, which is the only currently viable strain of T. fructosivorans. CT3 is the second strain in the genus Thiothrix that has been shown to be capable of growing autotrophically with reduced sulfur compounds as the sole energy source; autotrophy was also confirmed in strain I. The first reported chemolithoautotrophic isolate of this genus was a strain of 'Thiothrix ramosa' that was isolated from a hydrogen sulfide spring and is morphologically distinguishable from all other described strains of Thiothrix, including CT3. CT3 is an aerobic organism that is non-fermentative, not capable of denitrification and able to grow heterotrophically. Autotrophy in the genus Thiothrix should be investigated more fully to better define the taxonomy of this genus.
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A mathematical model that describes the operation of a sequential leach bed process for anaerobic digestion of organic fraction of municipal solid waste (MSW) is developed and validated. This model assumes that ultimate mineralisation of the organic component of the waste occurs in three steps, namely solubilisation of particulate matter, fermentation to volatile organic acids (modelled as acetic acid) along with liberation of carbon dioxide and hydrogen, and methanogenesis from acetate and hydrogen. The model incorporates the ionic equilibrium equations arising due to dissolution of carbon dioxide, generation of alkalinity from breakdown of solids and dissociation of acetic acid. Rather than a charge balance, a mass balance on the hydronium and hydroxide ions is used to calculate pH. The flow of liquid through the bed is modelled as occurring through two zones-a permeable zone with high flushing rates and the other more stagnant. Some of the kinetic parameters for the biological processes were obtained from batch MSW digestion experiments. The parameters for flow model were obtained from residence time distribution studies conducted using tritium as a tracer. The model was validated using data from leach bed digestion experiments in which a leachate volume equal to 10% of the fresh waste bed volume was sequenced. The model was then tested, without altering any kinetic or flow parameters, by varying volume of leachate that is sequenced between the beds. Simulations for sequencing/recirculating 5 and 30% of the bed volume are presented and compared with experimental results. (C) 2002 Elsevier Science B.V. All rights reserved.
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This paper presents a comparative study how reactor configuration, sludge loading and air flowrate affect flow regimes, hydrodynamics, floc size distribution and sludge solids-liquid separation properties. Three reactor configurations were studied in bench scale activated sludge bubble column reactor (BCR), air-lift reactor (ALR) and aerated stirred reactor (ASR). The ASR demonstrated the highest capacity of gas holdup and resistance, and homogeneity in flow regimes and shearing forces, resulting in producing large numbers of small and compact floes. The fluid dynamics in the ALR created regularly directed recirculation forces to enhance the gas holdup and sludge flocculation. The BCR distributed a high turbulent flow regime and non-homogeneity in gas holdup and mixing, and generated large numbers of larger and looser floes. The sludge size distributions, compressibility and settleability were significantly influenced by the reactor configurations associated with the flow regimes and hydrodynamics.