scholarly journals Flocculation performance of anionic starch in oil sand tailings

2018 ◽  
Vol 78 (6) ◽  
pp. 1268-1275
Author(s):  
Nana Zhao ◽  
Hani Al Bitar ◽  
Yunyin Zhu ◽  
Yuming Xu ◽  
Zhiqing Shi
Keyword(s):  
Specific Resistance ◽  
Kaolin Clay ◽  
Settling Rate ◽  
Oil Sand ◽  
Natural Polymers ◽  
Capillary Suction ◽  
Fine Tailings ◽  
Solids Content ◽  
Clay Suspensions

Abstract A series of carboxymethyl starches (CMSs), with various degrees of substitution from 0.1 to 0.79, were synthesized and selected as a model to study the feasibility of using natural polymers as flocculants for oil sand tailings treatment. The flocculation performance of modified CMS in kaolin clay suspensions and oil sand tailings was evaluated in terms of settling rate, solids content, capillary suction time, and specific resistance to filtration of the sediment phase. It was found that the synthesized CMS effectively accelerates settling of kaolin suspensions and oil sand fine tailings, thus demonstrating the feasibility of this application.

Comparison of lime and alum as oily sludge conditioners

1997 ◽  
Vol 36 (12) ◽  
pp. 117-124 ◽  
Author(s):  
Tay Joo Hwa ◽  
S. Jeyaseelan
Keyword(s):  
Specific Resistance ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Oily Sludge ◽  
Sludge Dewatering ◽  
Capillary Suction ◽  
Sludge Cake ◽  
Solids Content ◽  
Optimum Chemical

Chemical conditioning improves sludge dewatering. Choice of chemical conditioners is very much dependent on the characteristics of the sludges and the type of dewatering devices. Lime, alum, ferric chloride and polyelectrolytes are commonly used chemical conditioners. Anaerobic digested sludge samples collected from a sewage treatment plant with different oil contents varying from 1.8% to 8.0% by weight have been examined in the laboratory to find out their specific resistance, capillary suction time and filter yield. Lime and alum were used separately as conditioners. Different dosages of conditioner varying from 2% to 12% by weight were used to determine the optimum chemical dosage for varying oil contents. Lime dosages of about 6% were found to yield favourable characteristics. Addition of alum decreases the specific resistances and capillary suction times of oily sludges rapidly up to 4% dosages. Alum dosages beyond 4% only increase the solids content in the sludge cake and increase the sludge volume to be handled. A correlation between CST and specific resistance to filtration was established. CST can be measured easily and quickly in the laboratories. Using the CST and the correlation a quick prediction on dewaterability can be established.

Chemical Disequilibrium In Oil Sand Fine Tailings

1991 ◽  
Author(s):  
R. Jonasson ◽  
Z. Zhou ◽  
R. Schutte ◽  
L. Danielson
Keyword(s):  
Oil Sand ◽  
Fine Tailings

Conditioning of oily sludges with municipal solid wastes incinerator fly ash

1997 ◽  
Vol 35 (8) ◽  
pp. 231-238 ◽  
Author(s):  
Tay Joo Hwa ◽  
S. Jeyaseelan
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Specific Resistance ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Solid Wastes ◽  
Municipal Solid Wastes ◽  
Capillary Suction ◽  
Optimum Dosage

Conditioning of sludges improves dewatering characteristics and reduces the quantity of sludge to be handled. Anaerobic digested sludge collected from a sewage treatment plant contained 1.8% to 8% oil. The increase of specific resistance and capillary suction time (CST) with increasing oil content observed in these samples indicates the interference of oil in dewatering. It has been found that addition of municipal solid wastes incinerator fly ash decreases the specific resistances and capillary suction times of oily sludges rapidly up to 3% dosage. Beyond 3% fly ash, the decrease is less significant and the solids content in the sludge cake increases. This optimum dosage remains the same for sludges with varying oil contents from 1.8% to 12%. The total suspended solids of filtrate decreases with fly ash dosage but the toxic concentrations of heavy metals increases considerably. However at the optimum dosage of 3%, concentrations of heavy metals are within the limits for discharging into the sewers. The correlations of CST with the dewatering characteristics such as specific resistance, filter yield and corrected filter yield are established. These correlations can be used to obtain a quick prediction on dewaterability.

scholarly journals Using Specified Risk Materials-Based Peptides for Oil Sands Fluid Fine Tailings Management

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1582
Author(s):  
Yeling Zhu ◽  
Yuki Gong ◽  
Heather Kaminsky ◽  
Michael Chae ◽  
Paolo Mussone ◽  
...  
Keyword(s):  
Oil Sands ◽  
Colloidal Stability ◽  
Free Water ◽  
Value Added ◽  
Settling Rate ◽  
Test Range ◽  
Tailings Management ◽  
Fine Tailings ◽  
Fluid Fine Tailings ◽  
Hydrolyzed Polyacrylamide

Fluid fine tailings are produced in huge quantities by Canada’s mined oil sands industry. Due to the high colloidal stability of the contained fine solids, settling of fluid fine tailings can take hundreds of years, making the entrapped water unavailable and posing challenges to public health and the environment. This study focuses on developing value-added aggregation agents from specified risk materials (SRM), a waste protein stream from slaughterhouse industries, to achieve an improved separation of fluid fine tailings into free water and solids. Settling results using synthetic kaolinite slurries demonstrated that, though not as effective as hydrolyzed polyacrylamide, a commercial flocculant, the use of SRM-derived peptides enabled a 2-3-fold faster initial settling rate than the blank control. The pH of synthetic kaolinite tailings was observed to be slightly reduced with increasing peptides dosage in the test range (10–50 kg/ton). The experiments on diluted fluid fine tailings (as a representation of real oil sands tailings) demonstrated an optimum peptides dosage of 14 kg/ton, which resulted in a 4-fold faster initial settling rate compared to the untreated tailings. Overall, this study demonstrates the novelty and feasibility of using SRM-peptides to address intractable oil sands fluid tailings.

Capillary suction time (CST) as a measure of sludge dewaterability

1996 ◽  
Vol 34 (3-4) ◽  
pp. 443-448 ◽  
Author(s):  
G. W. Chen ◽  
W. W. Lin ◽  
D. J. Lee
Keyword(s):  
Water Content ◽  
Specific Resistance ◽  
Bound Water ◽  
The Other ◽  
Solid Concentration ◽  
Capillary Suction ◽  
Good Index ◽  
Other Hand ◽  
Sludge Dewaterability ◽  
Bound Water Content

The feasibility of employment of capillary suction time (CST) for characterizing the dewaterability of excess activated sludges was examined. The CST was shown as a good index for sludge filterability, if only the product of solid concentration and average specific resistance is of interest. On the other hand, the bound water content cannot be directly evaluated from the CST data.

Addition of Tubifex accelerates dewatering of oil sands tailings

2016 ◽  
Vol 43 (12) ◽  
pp. 1025-1033 ◽  
Author(s):  
Xiaojuan Yang ◽  
Miguel de Lucas Pardo ◽  
Maria Ibanez ◽  
Lijun Deng ◽  
Luca Sittoni ◽  
...  
Keyword(s):  
Oil Sands ◽  
Land Reclamation ◽  
Test Results ◽  
Anionic Polymer ◽  
Fine Tailings ◽  
Fluid Fine Tailings ◽  
Oil Sands Tailings ◽  
Set Up ◽  
Solids Content

Accelerating dewatering of fluid fine tailings (FFT) to facilitate land reclamation is a major challenge to the oil sands industry in Canada. A new method was tested, addition of Tubifex to FFT. Tubifex is an indigenous earthworm in Canada. The survival rate tests showed that Tubifex can survive in oil sands tailings and penetrate to 42 cm depth (maximum depth tested). Columns (5 L of FFT) were set-up with tailings alone, Tubifex treated tailings and polymer-Tubifex treated tailings. Test results showed that (a) the final mud–water interface of tailings alone was 26% higher than that of Tubifex treated tailings; (b) solids content of Tubifex treated tailings was 21% more than that of tailings alone; (c) Tubifex was capable to accelerate the dewatering process of both cationic and anionic polymer treated tailings; (d) anionic polymer was superior in facilitating long-term dewatering and its coupled effects with Tubifex were better than the cationic polymer.

Effect of various treatments on consolidation of oil sands fluid fine tailings

2018 ◽  
Vol 55 (8) ◽  
pp. 1059-1066 ◽  
Author(s):  
G. Ward Wilson ◽  
Louis K. Kabwe ◽  
Nicholas A. Beier ◽  
J. Don Scott
Keyword(s):  
Shear Strength ◽  
Oil Sands ◽  
Large Strain ◽  
Regulatory Requirements ◽  
Freeze Thaw ◽  
Treatment Processes ◽  
Fine Tailings ◽  
Fluid Fine Tailings ◽  
Solids Content ◽  
And Storage

Regulatory policy and regulations in Alberta require oil sands companies to reduce their production and storage of fluid fine tailings by creating deposits that can be reclaimed in a timely manner. To meet the regulatory requirements, some companies are adding flocculants to the fluid fine tailings and then using thickeners, inline flocculation or centrifuges to increase the solids content. Freeze–thaw and drying processes are then used to further dewater the tailings. The effects of flocculating, thickening, and freeze–thaw treatments were investigated by performing large-strain consolidation and shear strength tests on these treated fluid fine tailings. The consolidation and shear strength results were then compared with those of untreated fluid fine tailings. All of the treatments increased the hydraulic conductivity of the fluid fine tailings to some degree, but had little to no effect on the compressibility and shear strength. The effects of the treatment processes are discussed and evaluated.

Improving engineering properties of mature fine tailings using Tubifex

2020 ◽  
Vol 47 (7) ◽  
pp. 812-821
Author(s):  
Xiaojuan Yang ◽  
Miguel de Lucas Pardo ◽  
Maria Ibanez ◽  
Lijun Deng ◽  
Luca Sittoni ◽  
...  
Keyword(s):  
Survival Rate ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Engineering Properties ◽  
Test Results ◽  
Sulfate Content ◽  
Mature Fine Tailings ◽  
Fine Tailings ◽  
The Mean ◽  
Solids Content

The present study investigated the effects of Tubifex (Oligochaeta: Tubificidae) treatment on the dewatering process of mature fine tailings (MFT). Experiments testing the survival rate showed that Tubifex can survive at 20 °C and 4 °C. MFT with initial solids content (Sc) of 30% of total mass were treated in 11 settling columns by three Tubifex densities, 1400, 2000 and 4200 individuals·m−2. Test results showed that the mean survival rate at 20 °C and 4 °C on the 28th day stayed around 85%. Tubifex enhanced MFT dewatering by providing compacted tailings with 11.6% and 66.7% higher Sc and undrained shear strength compared with nontreated tailings. Tubifex accelerated pore water pressure dissipation. Tubifex did not affect the chemical composition of tailings except for a decrease in sulfate content. The Sc of tailings treated by Tubifex increased by 67.4% within nine months, which was 129% greater than the Sc increase of the nontreated tailings after 11 months.

scholarly journals The influence of different sludge concentrations on its dewaterability during bioleaching

2020 ◽  
Vol 81 (12) ◽  
pp. 2585-2598
Author(s):  
Wenfeng Yang ◽  
Liyuan Zeng ◽  
Weihao Zhang ◽  
Qiyong Yang ◽  
Tianfeng Wang ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Reduction Potential ◽  
High Efficiency ◽  
Specific Resistance ◽  
Principal Component ◽  
Buffering Capacity ◽  
Capillary Suction ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Sludge Dewaterability

Abstract Bioleaching, a technologically and economically feasible technology, is considered as the high efficiency method to improve dewaterability in sewage sludge. The objective of this study was to investigate the effect of different sludge concentrations on bioleaching dewaterability and understand the mechanism of the effect of bioleaching on sludge dewaterability. Variation in pH, oxidation-reduction potential (ORP), capillary suction time (CST), specific resistance to filtration (SRF) and different fractions of extracellular polymeric substances (EPS) including slime EPS (S-EPS), loosely bound EPS (LB-EPS), and tightly bound EPS (TB-EPS) were determined. Different sludge concentrations (5, 10, 15, 20 and 30 g·L−1) were selected to investigate during bioleaching. Results indicated that sludge buffering capacity significantly inhibited bioleaching efficiency as sludge concentrations increased. Optimum enhancements in sludge dewaterability were observed during the 10 g·L−1 sludge concentration treatment, and reached a maximum when the pH was 2.11. The variation of different fractions of EPS revealed that the ratio of S-EPS/TB-EPS significantly affected sludge dewaterability. Principal component analysis and Pearson's correlation analysis both provided evidence that the higher TB-EPS followed by a very large reduction was positively correlated with sludge dewaterability. However, the increase of protein and DNA in S-EPS content was negatively correlated with sludge dewaterability.

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