scholarly journals Rheology of Un-Sieved Concentrated Domestic Slurry: A Wide Gap Approach

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1287 ◽  
Author(s):  
Adithya Thota Radhakrishnan ◽  
Jules van Lier ◽  
Francois Clemens
Keyword(s):  
Yield Stress ◽  
Suspended Solids ◽  
Rotational Velocity ◽  
Pipeline Transportation ◽  
Inverse Power Law ◽  
Low Concentrations ◽  
Tikhonov Regularisation ◽  
Wide Gap ◽  
Sanitation Systems ◽  
Regularisation Method

Information on the rheology of domestic slurries is essential in designing pipeline transportation in novel sanitation systems. As concentrated slurries in their original collected state have wide particle size distribution, with particles up to 2 mm, a wide gap rheometer is used to acquire the rheograms. Rheograms obtained from a wide gap rheometer require a method to convert the rotational velocity to the shear rate, and this method must be robust to noisy data and yield stress in the slurry. For this purpose, a Tikhonov regularisation method is chosen as it suits the criteria the best. Using this, the rheograms are obtained for various total suspended solids (TSS) concentrations of slurries. A Herschel-Bulkley rheological model is used to represent the rheology of the slurries. The influence of the change in concentration of the slurries is represented through its influence on the Herschel-Bulkley parameters. The consistency index K exponentially increases with the concentration. The yield stress τ y , is 0 at low concentrations, and above 2.0% TSS (wt./wt.) exponentially increases with the concentration. The behaviour index n , is 1 at low concentrations, and above 2.6% TSS (wt./wt.) it decreases in an inverse power law with the concentration to reach a sort of plateau.

Experiments on high rate effluent filtration in the Netherlands

1998 ◽  
Vol 38 (3) ◽  
pp. 127-134
Author(s):  
Jaap H. J. M. van der Graaf ◽  
Arjen F. van Nieuwenhuijzen
Keyword(s):  
Wastewater Treatment ◽  
The Netherlands ◽  
Suspended Solids ◽  
Practical Experience ◽  
High Rate ◽  
Treated Water ◽  
Low Concentrations ◽  
Wastewater Treatment Effluent

As yet, filtration of wastewater treatment effluent has not been practised in the Netherlands. The main objections were the expected high costs. In order to gain practical experience an investigation programme studied the applicability and optimization of effluent filtration. Especially multi-layer filtration with the addition of ironchloride seemed to be very effective. Very low concentrations of suspended solids and phosphorus were achieved, even at high filtration rates (up to 30 m/h). This leads to an impressive reduction of expected costs, down to Dfl. 0.02/m3 (treated water).

Treatment of tunnel wash water and implications for its disposal

2014 ◽  
Vol 69 (10) ◽  
pp. 2029-2035 ◽  
Author(s):  
M. Hallberg ◽  
G. Renman ◽  
L. Byman ◽  
G. Svenstam ◽  
M. Norling
Keyword(s):  
Traffic Safety ◽  
Urban Areas ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Particulate Material ◽  
Wash Water ◽  
Polluted Water ◽  
Solids Concentration ◽  
Low Concentrations ◽  
Road Tunnels

The use of road tunnels in urban areas creates water pollution problems, since the tunnels must be frequently cleaned for traffic safety reasons. The washing generates extensive volumes of highly polluted water, for example, more than fivefold higher concentrations of suspended solids compared to highway runoff. The pollutants in the wash water have an affinity for particulate material, so sedimentation should be a viable treatment option. In this study, 12 in situ sedimentation trials were carried out on tunnel wash water, with and without addition of chemical flocculent. Initial suspended solids concentration ranged from 804 to 9,690 mg/L. With sedimentation times of less than 24 hours and use of a chemical flocculent, it was possible to reach low concentrations of suspended solids (<15 mg/L), PAH (<0.1 μg/L), As (<1.0 μg/L), Cd (<0.05 μg/L), Hg (<0.02 μg/L), Fe (<200 μg/L), Ni (<8 μg/L), Pb (<0.5 μg/L), Zn (<60 μg/L) and Cr (<8 μg/L). Acute Microtox® toxicity, mainly attributed to detergents used for the tunnel wash, decreased significantly at low suspended solids concentrations after sedimentation using a flocculent. The tunnel wash water did not inhibit nitrification. The treated water should be suitable for discharge into recipient waters or a wastewater treatment plant.

scholarly journals Metallicity and Superconductivity in Doped Strontium Titanate

2019 ◽  
Vol 10 (1) ◽  
pp. 25-44 ◽  
Author(s):  
Clément Collignon ◽  
Xiao Lin ◽  
Carl Willem Rischau ◽  
Benoît Fauqué ◽  
Kamran Behnia
Keyword(s):  
Liquid Helium ◽  
Free Path ◽  
Coulomb Interaction ◽  
Strontium Titanate ◽  
Room Temperature ◽  
Mean Free Path ◽  
Helium Temperature ◽  
Ongoing Research ◽  
Low Concentrations ◽  
Wide Gap

Strontium titanate is a wide-gap semiconductor avoiding a ferroelectric instability thanks to quantum fluctuations. This proximity leads to strong screening of static Coulomb interaction and paves the way for the emergence of a very dilute metal with extremely mobile carriers at liquid-helium temperature. Upon warming, mobility decreases by several orders of magnitude. Yet, metallicity persists above room temperature even when the apparent mean free path falls below the electron wavelength. The superconducting instability survives at exceptionally low concentrations and beyond the boundaries of Migdal–Eliashberg approximation. An intimate connection between dilute superconductivity and aborted ferroelectricity is widely suspected. In this review, we give a brief account of ongoing research on bulk strontium titanate as an insulator, a metal, and a superconductor.

Nitrification in partially aerated flocculation filters - a full-scale approach

1998 ◽  
Vol 38 (3) ◽  
pp. 135-142
Author(s):  
G. Kolisch
Keyword(s):  
Biological Treatment ◽  
Suspended Solids ◽  
Full Scale ◽  
Phosphorus Compounds ◽  
Decay Products ◽  
Low Concentrations ◽  
Aerated Filter ◽  
Anoxic Zones ◽  
Treatment Step

In a full-scale approach, we investigated whether nitrification can be carried out in partially aerated flocculation filters without compromising the removal of suspended solids. The objective is an aerated filter in addition to an advanced nitrification in the main biological treatment step to reduce low NH4-N concentrations in the effluent to very low concentrations. In two separate sets of experiments with an aerated filtering layer of 0.7 m and 1.4 m, nitrification rates up to 14 g N/(m3/h) were achieved. Compared to unaerated chambers, there was approximately the same removal of particulate COD and of precipitated phosphorus compounds. Due to the formation of anoxic zones, nonspecific denitrification occurred in the chambers under both conditions. Decay products are suspected to be the endogenous H-donors.

scholarly journals Effects of Fly Ash and Chemical Admixtures on the Rheological Properties of High-Concentration Full-Tailing Filling Slurry

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Fulin Wang ◽  
Faguang Yang ◽  
Zhengping Yuan ◽  
Shijiao Yang
Keyword(s):  
Fly Ash ◽  
Rheological Properties ◽  
Yield Stress ◽  
Polyethylene Oxide ◽  
Viscosity Coefficient ◽  
Pipeline Transportation ◽  
High Concentration ◽  
Polycarboxylate Superplasticizer ◽  
Chemical Admixtures

Good fluidity is the precondition to ensure the pipeline transportation of the filling slurry. The admixture in the filling slurry will affect the rheological properties of the slurry. In this paper, yield stress (YS), viscosity coefficient (VC), and expansion (ED) of the filling slurry were measured by the MCR52 rheometer and expansion tester, respectively, and the influence regularities of the three kinds of admixtures including fly ash (FA), polycarboxylate superplasticizer (PS), and polyethylene oxide (PEO) on the rheological properties of the filling slurry were obtained. The results show that when other conditions are fixed, the fluidity of the slurry becomes worse with the increase of the amount of fly ash but improves with the increase of the amount of the polycarboxylate superplasticizer; polyethylene oxide is not suitable for the improvement of the fluidity of the high-concentration full-tailing filling slurry, and the fluidity of the slurry becomes worse rapidly with the increase of the amount of polyethylene oxide.

The Measurement and Analysis on the Coal Slime Yield Stress

2012 ◽  
Vol 503-504 ◽  
pp. 1522-1526
Author(s):  
Jie Gao ◽  
Xue Di Hao ◽  
Zhi Nan Wang ◽  
Na Li ◽  
Miao Wu
Keyword(s):  
Yield Stress ◽  
Volume Concentration ◽  
Important Process ◽  
Pipeline Transportation ◽  
Measurement And Analysis ◽  
Specific Device ◽  
Pressure Pipeline ◽  
Industrial Use ◽  
Coal Slime ◽  
High Pressure Pipeline

Pipeline transportation is an important process of mass industrial use of coal slime. The coal slime is transported in the form of dense pastes under high pressure pipeline. The coal slime yield stress is an important factor to design the pipeline transportation system, but the study on paste yield stress is less seen in published at present. The coal slime yield stress is measured with specific device in this article. Both curves of the speed and the volume concentration on the coal slime yield stress are studied. The relation between the coal slime yield stress and the volume concentration are obtained.

Urban snow dump quality and pollutant reduction in snowmelt by sedimentation

1993 ◽  
Vol 20 (1) ◽  
pp. 9-21 ◽  
Author(s):  
R. L. Droste ◽  
J. C. Johnston
Keyword(s):  
Suspended Solids ◽  
Specific Conductance ◽  
Fecal Coliforms ◽  
Snowmelt Runoff ◽  
Dump Site ◽  
Time Period ◽  
Low Concentrations ◽  
Pollutant Reduction ◽  
Very High ◽  
Better Than

Four snow dump sites in the Ottawa-Carleton region were analyzed for BOD, total and fecal coliforms, chlorides, sulfates, specific conductance, suspended solids, metals, and other parameters. Sites were sampled at various depths during the months of February through May. There was no trend in variation of quality in the dump piles with time. The black crust that formed on the top of the pile was heavily laden with solids and metals.Snowmelt samples were also taken over the same time period and analyzed for the above parameters. The process of snowmelt reduced the concentrations of most metals and suspended solids from the dump by 50–70%. Dissolved constituents in snowmelt are discharged at very high levels during the initial stages of snowmelt and rapidly decrease to low concentrations. Suspended solids and associated metals in snowmelt exhibited variability with snowmelt conditions and the state of the dump pile. The concentrations of a number of metals in settled snowmelt exceeded provincial objectives for surface waters.An analysis of settled snow dump and snowmelt samples for suspended solids and metals was conducted for settling periods of 1, 6, 12, and 24 h. A settling time from 2 to 6 h would achieve most of the removal that could be expected from sedimentation. The overall removal of suspended solids and the metals in settled snowmelt would generally be better than 90%. There were no significant trends in removal behavior as the snowmelt season progressed. The removal of metals lagged slightly behind the removal of suspended solids after settling because of the stronger association of metals with smaller sediment particles. The residue at the dump site is highly contaminated. Key words: snowmelt, runoff, stormwater, sedimentation, road deicing, snow dump, pollution.

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