scholarly journals Modeling of the Suspended Solid Removal of a Granular Media Layer in an Upflow Stormwater Runoff Filtration System

2021 ◽  
Vol 11 (13) ◽  
pp. 6202
Author(s):  
Yuhoon Hwang ◽  
Younggyo Seo ◽  
Seokoh Ko ◽  
Dogun Kim

Upflow granular media filtration devices are widely used for stormwater runoff treatment. However, the system performance is not well characterized due to the irregular removal of suspended solid (SS) in the pretreatment (sedimentation) chamber and, hence, its irregular input to the media layer. In this regard, the performance of the granular media layer of an upflow filtration system is investigated herein by the use of various models. Due to the significant variation in the SS concentration of the influent and effluent to and from the media layer, the deep bed filtration model, the k-C* model, and the porous media capture model provide limited descriptions of the system performance. By contrast, the performance is well described using the kinetic model, the modified k-C* model using a specific deposit, and the modified porous media capture model using a specific deposit. The parameters of the latter models are shown to be in good correlation with the filtration velocity, SS removal, and specific deposit. The results suggest that modeling using a specific SS deposit can provide an accurate description of the granular media layer performance under a highly variable influent SS concentration.

2018 ◽  
Vol 2 (21) ◽  
pp. 85-101
Author(s):  
Olga Shtyka ◽  
Łukasz Przybysz ◽  
Mariola Błaszczyk ◽  
Jerzy P. Sęk

The research focuses on the issues concerning a process of multiphase liquids transport in granular porous media driven by the capillary pressure. The current publication is meant to introduce the results of experimental research conducted to evaluate the kinetics of the imbibition and emulsions behavior inside the porous structures. Moreover, the influence of the dispersed phase concentration and granular media structure on the mentioned process was considered. The medium imbibition with emulsifier-stabilized emulsions composed of oil as the dispersed phase in concentrations of 10 vol%, 30 vol%, and 50 vol%, was investigated. The porous media consisted of oleophilic/hydrophilic beads with a fraction of 200–300 and 600–800 μm. The experimental results provided that the emulsions imbibition in such media depended stronger on its structure compare to single-phase liquids. The increase of the dispersed phase concentration caused an insignificant mass decreasing of the imbibed emulsions and height of its penetration in a sorptive medium. The concentrations of the imbibed dispersions exceeded their initial values, but reduced with permeants front raise in the granular structures that can be defined as the influential factor for wicking process kinetics.


Author(s):  
Wojciech Sobieski

AbstractThe paper describes the so-called Waterfall Algorithm, which may be used to calculate a set of parameters characterising the spatial structure of granular porous media, such as shift ratio, collision density ratio, consolidation ratio, path length and minimum tortuosity. The study is performed for 1800 different two-dimensional random pore structures. In each geometry, 100 individual paths are calculated. The impact of porosity and the particle size on the above-mentioned parameters is investigated. It was stated in the paper, that the minimum tortuosity calculated by the Waterfall Algorithm cannot be used directly as a representative tortuosity of pore channels in the Kozeny or the Carman meaning. However, it may be used indirect by making the assumption that a unambiguous relationship between the representative tortuosity and the minimum tortuosity exists. It was also stated, that the new parameters defined in the present study are sensitive on the porosity and the particle size and may be therefore applied as indicators of the geometry structure of granular media. The Waterfall Algorithm is compared with other methods of determining the tortuosity: A-Star Algorithm, Path Searching Algorithm, Random Walk technique, Path Tracking Method and the methodology of calculating the hydraulic tortuosity based on the Lattice Boltzmann Method. A very short calculation time is the main advantage of the Waterfall Algorithm, what meant, that it may be applied in a very large granular porous media.


2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Navid Shahangian ◽  
Damon Honnery ◽  
Jamil Ghojel

Interest is growing in the benefits of homogeneous charge compression ignition engines. In this paper, we investigate a novel approach to the development of a homogenous charge-like environment through the use of porous media. The primary purpose of the media is to enhance the spread as well as the evaporation process of the high pressure fuel spray to achieve charge homogenization. In this paper, we show through high speed visualizations of both cold and hot spray events, how porous media interactions can give rise to greater fuel air mixing and what role system pressure and temperature plays in further enhancing this process.


Geophysics ◽  
1956 ◽  
Vol 21 (3) ◽  
pp. 691-714 ◽  
Author(s):  
Norman R. Paterson

Theoretical and experimental studies have been made of the manner in which sound waves are propagated in porous granular aggregates. A cylindrical piezo‐electric source is used and this simulates the explosion of a charge in a seismic shot‐hole. It is found that in general two waves of volume expansion are propagated and that these involve coupled displacements of both constituents of the media. The waves are termed frame‐waves, air‐waves or liquid‐waves depending upon the nature of the pore‐filler and the relative displacements of the constituents. The frame‐wave velocity is dependent upon the strength of the frame, the densities of solid and pore‐filling materials and the texture of the medium. Air‐ and liquid‐wave velocities are related to the texture of the medium and to the density and viscosity of the pore‐filler. Frame‐strength is important to a lesser degree. Waves are dispersive only in the case of media of very low permeability. Attenuation is related to viscosity, texture and frequency. Scattering is probably important only at the highest frequencies and largest particle diameters used in the experiments. It is shown that porosity and permeability of a beach sand can be inferred from velocity measurements. These properties provide information regarding grain‐size, sorting and the nature of the pore‐filler.


Author(s):  
Gennadiy Sandrakov ◽  
Andrii Hulianytskyi ◽  
Vladimir Semenov

Modeling of dynamic processes of diffusion and filtration of liquids in porous media are discussed. The media are formed by a large number of blocks with low permeability, and separated by a connected system of faults with high permeability. The modeling is based on solving initial boundary value problems for parabolic equations of diffusion and filtration in porous media. The structure of the media leads to the dependence of the equations on a small parameter. Assertions on the solvability and regularity of such problems and the corresponding homogenized convolution problems are considered. The statements are actual for the numerical solution of this problem with guaranteed accuracy that is necessary to model the considered processes.


Journalism ◽  
2017 ◽  
Vol 19 (8) ◽  
pp. 1182-1195 ◽  
Author(s):  
Angela Woodall

Much has been written about the potential of large-scale digital disclosures, or ‘megaleaks’, to transform journalistic coverage of high-value news. This analysis takes a second look at the phenomenon by analyzing three of the best-known megaleaks to date: those disclosed by Chelsea Manning, Edward Snowden, and John Doe, the source of the Panama Papers. To what extent did these large-scale disclosures disrupt the media capture that distorts or limits coverage by an autonomous press? A study of circumstances surrounding these three megaleaks suggests that their main effect was encouraging a culture of collaborative work that favors independence from official sources.


Author(s):  
Vincenzo Farina ◽  
Lucrezia Fattobene ◽  
Elvira Anna Graziano

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Sandy von Salisch ◽  
Josephina Haunschild ◽  
Martin Misfeld ◽  
Michael A Borger ◽  
Stefan Dhein ◽  
...  

Background: Bicuspid aortic valve is the most frequent congenital cardiac abnormality and associated with proximal aortic disease (i.e. aneurysm, dissection or rupture). Granular media calcinosis(GMC)--suggested to increase stiffness and play a pathogenetic role in dissecting aneurysm--has not yet been quantified in BAV. Methods: Specimen of the proximal aortic wall from 76 patients--32 with tricuspid (TAV) and 44 with bicuspid aortic valve (BAV)--were obtained during surgery to quantify media thickness and GMC by von Kossa staining (panel C), comparing the convexity (Cvx) and concavity (Ccv) in BAV vs. TAV. Results: Interlamellar GMC affected the most central layers of the media and those adjacent to the outer adventitia with a doubling within both--the Cvx and Ccv--of pts with BAV compared to patients with TAV (13.3±9.6 vs. 6.6±7.4 and 12.8±10.8 vs. 6.4±7.1; p<0.05, panel A) was seen, but neither a difference in calcification between the Ccx and the Ccv side within the BAV nor the TAV group. No association between age and calcification grade , neither in the Cvx nor the Ccv (r=0.132, p=0.218 and 0.103, p=0.341) was seen. There was a significant difference in the total media thickness between BAV and TAV at the Cvx (867±162μm vs . 993±158μm; p<0.05) and the Ccv (1005 ± 236 vs 1223 ± 217μm; p<0.05, panel B). Independent of aortic valve morphology, the Cvx was thinner than the Ccv side (TAV: 993 ± 158 vs.1223 ± 217μm; p<0.001; BAV: 869 ± 162 vs.1005 ± 236μm; p<0.05, panel B). Conclusion: BAVs had significantly thinner media and twice as much GMC than their tricuspid peers possibly associated with the loosening of the bond between the elastic lamellae causing a decrease in elasticity possibly explaining a higher risk for dissection and rupture.


2019 ◽  
Vol 79 (4) ◽  
pp. 771-778 ◽  
Author(s):  
Junho Lee ◽  
Myungjin Lee

Abstract This study has been carried out to evaluate the applicability of the pilot scale hybrid type of stormwater runoff treatment system for treatment of combined sewer overflow. Also, to determine the optimum operation parameter such as coagulation dosage concentration, effectiveness of coagulant usage, surface loading rate and backwashing conditions. The pilot scale stormwater filtration system (SFS) was installed at the municipal wastewater plant serving the city of Cheongju (CWTP), Korea. CWTP has a capacity of 280,000 m3/day. The SFS consists of a hydrocyclone coagulation/flocculation with polyaluminium chloride silicate (PACS) and an upflow filter to treat combined sewer overflows. There are two modes (without PACS use and with PACS use) of operation for the SFS. In case of no coagulant use, the range of suspended solids (SS) and turbidity removal efficiency were 72.0–86.6% (mean 80.0%) and 30.9–71.1% (mean 49.3%), respectively. And, the recovery rate of filter was 79.2–83.6% (mean 81.2%); the rate of remaining solid loading in filter media was 16.4–20.8% (mean 18.8%) after backwashing. The influent turbidity, SS concentrations were 59.0–90.7 NTU (mean 72.0 NTU), 194.0–320.0mg/L (mean 246.7mg/L), respectively. The range of PACS dosage concentration was 6.0–7.1mg/L (mean 6.7mg/L). The range of SS and turbidity removal efficiency was 84.9–98.2 (mean 91.4%) and 70.7–96.3 (mean 84.0%), respectively. It was found that removal efficiency was enhanced with PACS dosage. The recovery rate of filter was 92.0–92.5% (mean 92.3%) the rate of remaining solid loading in filter media was 6.1–8.2% (mean 7.2%) after backwashing. In the case of coagulant use, the particle size of the effluent is bigger than influent particle size. The results showed that SFS with PACS use more effective than without PACS use in SS and turbidity removal efficiency and recovery rate of filter.


Author(s):  
Luh Putri Kriswidatari ◽  
I W Budiarsa Suyasa ◽  
I Made Siaka

BIODEGRADATION REMAZOL BRILLIANT BLUE IN VERTICAL FILTRATION SYSTEM WITH INOKULUM BACTERIA FROM DIED SEDIMEN RIVER IMAM BONJOL DENPASARThe biodegradation research of Remazol Brilliant Blue (RBB) has been done in vertical biofiltration systems with bacterial inoculum that had seed from soil Mati River Imam Bonjol Denpasar. This aims of research are to obtain the best active suspension grown from soil samples of Mati river sediment and to determine the magnitude of the effectiveness and capacity of biosystem . The artificial waste water of RBB has made with a concentration of 200 mg/L. In the first phase, the best active suspension is obtained by determining the value of VSS ( Volatile Suspended Solid ) is the highest as a source of inoculum of bacteria capable of degrading RBB. While the second phase, the effectiveness and capacity of biosystem is obtained by determining the levels of waste of artificial RBB vertical biofiltration system (biosystem). Biofilm has made with attached bacteria consortium in volcanic rock for 7 days. RBB subsequently incoporated into it to determine the concentration of it and to determine the effectiveness and capacity and identified the bacteria contained in biosystem. The results showed the best sludge active from soil sediments of the Mati River Imam Bonjol Gang Keladian with a value of Volatile Suspended Solid (VSS) highest of 17200 mg/L when the sreeding time of 48 hours. The results of processing using biosystem known to decreased when the processing time from 6 hours up to 114 hours, from concentration of 200 mg/L to 19.6211 mg/L. Then the prosses has increased again into 19.8209 mg/L at the time to 120 hours. The highest effectivity of biosystem to degrading remazol brilliant blue of  90.19 % for 114 hours , while the highest capacity is obtained from the biosystem is 1.6525 x mg /g for 114 hours. The bacteria that act to decreased identified as Pseudomonas sp., Aeromonas sp . and Plesiomonas sp, with Pseudomonas sp more dominant in the  degrading of dye RBB. The value of the colonists before degradation of 7.2 x CFU/gr and the value after the degradation of 2.6 x CFU/gr.


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