Rheological behavior of sewage sludge with high solid content

2015 ◽  
Vol 71 (11) ◽  
pp. 1686-1693 ◽  
Author(s):  
Yingchao Cheng ◽  
Huan Li
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Exponential Model ◽  
Organic Content ◽  
Complex Model ◽  
Solid Content ◽  
High Solids ◽  
Pseudoplastic Fluid ◽  
Model Combining ◽  
Solids Content

Sludge rheological properties play a fundamental role in determining its performance in pipes, tanks or reactors. However, the relative information on high-solids sludge is very rare. In this study, the rheological properties of high-solids sludge were investigated systematically and a new rheological model was built. The results showed that the low-solids sludge with total solids content (TS) 2–15% was pseudoplastic fluid, and the high-solids sludge with TS 7–15% exhibited thixotropic property. Sludge viscosity increased exponentially with the increasing TS, and decreased in function of power along with the increasing shear rate. The new complex model combining the exponential model and the power model can perfectly describe the relation between TS, shear rate and viscosity of the high-solids sludge. Both sludge organic content and temperature have influence on sludge viscosity, but the influence was not significant for the low-solids sludge. For the high-solids sludge with TS 6%, 8%, 10% and 12%, their viscosities increased by 5.0, 9.1, 25.7 and 24.9 times, respectively, when sludge organic content increased from 28% to 53%, and decreased by 36.5%, 49.5%, 54.0% and 65.4%, respectively, when sludge temperature rose from 9 to 55 °C.

Rheological Properties and Anti-Aging Properties of PP/PP-g-AN Blends

2013 ◽  
Vol 815 ◽  
pp. 579-583 ◽  
Author(s):  
Ya Zhen Wang ◽  
Cheng E Yue ◽  
Di Ma ◽  
Wei Nan Jia ◽  
Yong Li
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Solid Phase ◽  
Testing Time ◽  
Pseudoplastic Fluid ◽  
Aging Properties

The effect of PP-g-AN prepared by solid phase grafting on the blends of PP/PP-g-AN was investigated in this paper. The influence of aging testing time, PP-g-AN additives concentration, shear rate on the rheological properties and anti-aging properties of PP/PP-g-AN were mainly discussed. The results show that PP/PP-g-AN blends are pseudoplastic fluid and the presence of PP-g-AN can restrain the degradation of polypropylene when the content of PP-g-AN is in a certain range.

Rheological Properties of an Electrorheological Fluid in Original Transition Zone

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1893-1900
Author(s):  
Fan Zhikang ◽  
Liang Shuhua ◽  
Xue Xu ◽  
Wang Gang
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Transition Zone ◽  
Electrorheological Fluid ◽  
Concentric Cylinder ◽  
Pseudoplastic Fluid ◽  
Applied Fields ◽  
Er Fluid ◽  
Regressive Analysis ◽  
Cylinder Viscometer

The rheological properties of an electrorheological(ER) fluid have been studied in a modified concentric cylinder viscometer. The results show that the relation of shear rate and shear stress is non-linear at certain shear rate defined as an original transition zone. Regressive analysis reveals that the ER fluid is of yield-pseudoplastic fluid in the transition zone. With increase in applied fields, the rheological properties of the ER fluid deviates from Newtonian fluid and the length of the transition zone becomes longer.

Physical and Rheological Properties of Animal Manure: A Review

2018 ◽  
Vol 61 (3) ◽  
pp. 1113-1120
Author(s):  
Ibrahim Denka Kariyama ◽  
Xiaodong Zhai ◽  
Binxin Wu
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Apparent Viscosity ◽  
Flow Behavior ◽  
Pressure Head ◽  
Animal Manure ◽  
Anaerobic Treatment ◽  
Pseudoplastic Fluid ◽  
Power Law Equation

Abstract. This literature review was conducted on the physical and rheological properties of animal manure slurries and their applications. The review revealed the importance of these properties in the design of anaerobic treatment plants, pipe systems to transport slurries to treatment and storage units, and other applications and management of raw and treated slurries. The selection of pumping and mixing equipment and their power requirements, the flow behavior, mass, and heat transfer, the quality of mixing, pressure head loss, and other applications of manure slurries are affected by the physical and rheological properties. The review shows that manure slurries generally exhibit non-Newtonian pseudoplastic fluid behavior with a decreasing apparent viscosity as the shear rate increases and that the power law equation can successfully be used to describe the relationship between shear stress and shear rate, especially for low total solids concentrations. Keywords: Animal manure slurries, Apparent viscosity, Non-Newtonian pseudoplastic fluids, Power law equation, Rheological properties.

APLIKASI PROSES DIGESTASI ANAEROBIK LUMPUR BIOLOGI INSTALASI PENGOLAHAN AIR LIMBAH INDUSTRI KERTAS

2014 ◽  
Vol 4 (02) ◽  
Author(s):  
Rina S. Soetopo ◽  
Sri Purwati ◽  
Henggar Hardiani ◽  
Mukharomah Nur Aini ◽  
Krisna Adhitya Wardhana
Keyword(s):  
Oxygen Demand ◽  
Total Solid ◽  
Pilot Scale ◽  
Organic Content ◽  
Solid Content ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Organic Loading ◽  
Total Solid Content ◽  
Average Value

A continuous pilot scale study has been conducted to investigate the effectiveness of anaerobic digestion of biological sludge. The sludge has a total solid content of 0.53% - 1.1%, pH of 7.20 to 7.32. Its organic content is about 97 %, The research were conducted in two stages, which are acidification (performed in 3 m3 the Continously Stirred Tank Reactor/CSTR at pH of 5.5 to 6.0) and methanation (performed in 5 m3 the Up Flow Anaerobic Sludge Blanket/UASB reactor at pH 6.5 to 7.0). The retention time (RT) was gradually shortened from 6 days to 1 day for acidification and from 8 days to 2 days for methanation. The results showed that operating the CSTR at the RT of 1 day and the organic loading of 8.23 g Volatile Solid (VS)/m3.day could produce Volatile Fatty Acid (VFA) at an average value of 17.3 g/kg VS.day. Operating the UASB reactor at the RT of 2 days and the organic loading (Chemical Oxygen Demand/COD) of 2.4 kg COD/m3.day could produce biogas at an average value of 66.3 L/day, with an average methane content of 69.9%, methane rate of 0.17 L CH4/g COD reduction or 19.06 L CH4/kg VS. Furthermore, methanation could reduce COD at an average value of 51.2 %, resulting in the effluent average value of COD filtrate and COD total of 210.1 mg/L and 375.2 mg /L, respectively.Keywords: acidification, methanation, CSTR, UASB, biogas ABSTRAKPercobaan digestasi anaerobik lumpur IPAL biologi industri kertas secara kontinyu skala pilot telah dilakukan di industri kertas dengan tujuan mengkaji efektivitas proses digestasi anaerobik dalam mengolah lumpur tersebut. Lumpur yang digunakan memiliki total solids sekitar 0,53% – 1,1%, pH netral (7,20 – 7,32) dengan komponen utama senyawa organik sekitar 97%. Percobaan dilakukan dalam dua tahap yaitu asidifikasi dalam reaktor CSTR berkapasitas 3 m3 pada pH 5,5 – 6,0 dan metanasi dalam reaktor UASB berkapasitas 5 m3 pada pH 6,5 – 7,0. Percobaan dilakukan dengan waktu retensi yang dipersingkat secara bertahap dari 6 hari ke 1 hari untuk proses asidifikasi dan dari 8 hari ke 2 hari untuk proses metanasi. Hasil percobaan menunjukkan bahwa pengoperasian reaktor CSTR dengan waktu retensi 1 hari dan beban organik 8,3 g VS/m3.hari dapat menghasilkan VFA rata-rata 17,3 g/kg VS.hari dengan kisaran 8,36 – 30,59 g/kg VS.hari, sedangkan pengoperasian reaktor UASB pada waktu retensi 2 hari dan beban organik 2,4 kg COD/m3.hari dapat menghasilkan biogas rata-rata 66,3 L/hari dengan kadar metana rata-rata 69,9% atau 0,17 L CH4/g COD reduksi atau 19,06 L CH4/kg VS. Selain itu proses metanasi dapat menurunkan COD terlarut rata-rata 51,2%, dengan konsentrasi efluen COD terlarut  rata-rata 210,1 mg/L dan COD total rata-rata 375,2 mg/L.Kata kunci: asidifikasi, metanasi, CSTR, UASB, biogas

Deep Shaft High Rate Aerobic Digestion: Laboratory and Pilot Plant Performance

1981 ◽  
Vol 16 (1) ◽  
pp. 71-90 ◽  
Author(s):  
F. Tran ◽  
D. Gannon
Keyword(s):  
Retention Time ◽  
Oxygen Transfer ◽  
Pilot Plant ◽  
High Rate ◽  
Plant Performance ◽  
High Solids ◽  
Aerobic Digestion ◽  
Volatile Solids ◽  
Solids Content ◽  
High Solids Content

Abstract The Deep Shaft process, originating from ICI Ltd. in the U.K., has been further developed by C-I-L Inc., Eco-Technology Division into an extremely energy efficient, high rate biological treatment process for industrial and municipal wastewaters. The Deep Shaft is essentially an air-lift reactor, sunk deep in the ground (100 - 160 m): the resulting high hydrostatic pressure together with very efficient mixing in the shaft provide extremely high oxygen transfer efficiencies (O.T.E.) of up to 90% vs 4 to 20% in other aerators. This high O.T.E. suggests real potential for Deep Shaft technology in the aerobic digestion of sludges and animal wastes: with conventional aerobic digesters an O.T.E. over 8% is extremely difficult to achieve. This paper describes laboratory and pilot plant Deep Shaft aerobic digester (DSAD) studies carried out at Eco-Research's Pointe Claire, Quebec laboratories, and at the Paris, Ontario pilot Deep Shaft digester. An economic pre-evaluation indicated that DSAD had the greatest potential for treating high solids content primary or secondary sludge (3-7% total solids) in the high mesophilic and thermophilic temperature range (25-60°C) i.e. in cases where conventional digesters would experience severe limitations of oxygen transfer. Laboratory and pilot plant studies have accordingly concentrated on high solids content sludge digestion as a function of temperature. Laboratory scale daily draw and fill DSAD runs with a 5% solids sludge at 33°C with a 3 day retention time have achieved 34% volatile solids reduction and a stabilized sludge exhibiting a specific oxygen uptake rate (S.O.U.R.) of less than 1 mgO2/gVSS/hour, measured at 20°C. This digestion rate is about four times faster than the best conventional digesters. Using Eco-Research's Paris, Ontario pilot scale DSAD (a 160 m deep 8 cm diameter u-tube), a 40% reduction in total volatile solids, (or 73% reduction of biodegradable VS) and a final SOUR of 1.2 mg02/gVSS/hour have been achieved for a 4.6% solids sludge in 4 days at 33°C, with loading rates of up to 7.9 kg VSS/m3-day. Laboratory runs at thermophilic temperatures (up to 60°C) have demonstrated that a stabilized sludge (24-41% VSS reduction) can be produced in retention time of 2 days or less, with a resulting loading rate exceeding 10 kg VSS/m3-day.

Enhanced sludge conditioning by enzyme pre-treatment: comparison of laboratory and pilot scale dewatering results

2006 ◽  
Vol 54 (5) ◽  
pp. 33-41 ◽  
Author(s):  
D. Dursun ◽  
M. Turkmen ◽  
M. Abu-Orf ◽  
S.K. Dentel
Keyword(s):  
Extracellular Polymeric Substances ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Solid Content ◽  
Filter Press ◽  
Treatment Comparison ◽  
Anaerobically Digested Sludge ◽  
Network Strength ◽  
Pre Treatment ◽  
Solids Content

The effect of enzyme pre-treatment on dewaterability of anaerobically digested sludge was investigated at both laboratory and pilot scale. Our results revealed a significant increase in cake solid content (27% cake solids compared to 18% without enzyme pre-treatment), using an enzyme dose of only 20 mg/L. In order to assess practical application, enzyme pre-treatment was applied at the Wilmington, Delaware (US) wastewater treatment plant, using a pilot-scale centrifuge. However, the efficiency reached in laboratory scale could not be obtained in pilot scale, where the final cake solids content did not exceed 20%. Centrifuge and belt filter press (simulated by Crown Press™) dewatering were compared in terms of the process efficiencies in the absence and presence of enzyme pre-treatment. Possible factors that might cause the differences were tested by experimental and statistical comparisons. Results indicated that the higher shear applied in centrifugation is responsible for the lack of improved cake solids. The network strength of sludge determined by rheological measurements revealed that enzymatic treatment weakens the gel structure of the sludge floc through the hydrolysis of extracellular polymeric substances; this allows improved dewatering by filtration processes, but leads to floc deterioration when subjected to high shear during centrifugation.

Effect of Shear Surface Boundaries on Stress for Shearing Flow of Dry Metal Powders—An Experimental Study

1987 ◽  
Vol 109 (2) ◽  
pp. 232-237 ◽  
Author(s):  
K. Craig ◽  
R. H. Buckholz ◽  
G. Domoto
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Normal Stress ◽  
Particle Diameter ◽  
Surface Boundary ◽  
Metal Powders ◽  
Shear Surface ◽  
Shear Cell ◽  
Shearing Flow ◽  
Solids Content

This paper studies the rapid simple shearing flow of dry cohesionless metal powders contained between parallel rotating plates. In this study, an annular shear cell test apparatus was used; the dry metal powders are rapidly sheared by rotating one of the shear surfaces while the other shear surface remains fixed. Such a flow geometry is of interest to tribologists working in the area of dry or powder lubrication. The shear stress and normal stress on the stationary surface are measured as a function of the following parameters: shear surface boundary material and roughness, the shear-cell gap thickness, the shear-rate and the fractional solids content. Both the fractional solids content and the gap thickness are kept at prescribed values during stress measurements. In this experiment the metal powder tested is different from the shear transmission surface material; the effect on the measured normal and shear stress data are reported. The results show the dependence of the normal stress and the shear stress on the shear-rate, particle density and particle diameter. Likewise, a significant stress dependence on both the fractional solids content and the shear-cell gap thickness was observed.

Sign in / Sign up

Export Citation Format

Share Document