Dewatering Characteristics of Oily Sludge

1993 ◽  
Vol 28 (1) ◽  
pp. 249-256 ◽  
Author(s):  
Joo-Hwa Tay ◽  
S. Jeyaseelan
Keyword(s):  
Oil Content ◽  
Specific Resistance ◽  
Solid Content ◽  
Oily Sludge ◽  
Capillary Suction ◽  
Optimum Dosage ◽  
Sludge Conditioning

Proper sludge conditioning facilitates better dewatering of sludges. Sludge conditioning techniques required for different sludges bigbly depend on the properties of the sludges. Dewatering characteristics of oily sludges were studied for different degrees of oil content in sludge with lime as sludge conditioner. The optimum dosage of lime was found to range from 6% to 10% to yield favourable characteristics of the sludge for better filterability. Also the established correlations between the combinations of dewatering characteristics, such as specific resistance, capillary suction time, cake solid content and filter yield provide means of quick indication for the nature of the sludges.

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.

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.

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.

scholarly journals Enhanced Separation of Oil and Solids in Oily Sludge by Froth Flotation at Normal Temperature

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2163
Author(s):  
Wenying Li ◽  
Hongyang Lin ◽  
Yang Yang ◽  
Zhenxiao Shang ◽  
Qiuhong Li ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Oil Content ◽  
Froth Flotation ◽  
Hazardous Materials ◽  
Impeller Speed ◽  
Oily Sludge ◽  
Shear Effect ◽  
Flotation Reagent ◽  
Shengli Oilfield ◽  
Pulp Viscosity

Oily sludge (OS) contains a large number of hazardous materials, and froth flotation can achieve oil recovery and non-hazardous disposal of OS simultaneously. The influence of flotation parameters on OS treatment and the flotation mechanism were studied. OS samples were taken from Shengli Oilfield in May 2017 (OSS) and May 2020 (OST), respectively. Results showed that Na2SiO3 was the suitable flotation reagent treating OSS and OST, which could reduce the viscosity between oil and solids. Increasing flotation time, impeller speed and the ratio of liquid to OS could enhance the pulp shear effect, facilitate the formation of bubble and reduce pulp viscosity, respectively. Under the optimized parameters, the oil content of OST residue could be reduced to 1.2%, and that of OSS could be reduced to 0.6% because of OSS with low heavy oil components and wide solid particle size distribution. Orthogonal experimental results showed that the impeller speed was the most significant factor of all parameters for OSS and OST, and it could produce shear force to decrease the intensity of C-H bonds and destabilize the OS. The oil content of residue could be reduced effectively in the temperature range of 24–45 °C under the action of high impeller speed.

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.

Ultrasound-UV Method Detect Oil Content of Oily Sludge from Daqing Oilfield

2010 ◽  
Vol 113-116 ◽  
pp. 2292-2295
Author(s):  
Jie Zhang ◽  
Zhao Yang Wang ◽  
Jing Xin Sun ◽  
Li Wei ◽  
Bin Song Wang ◽  
...  
Keyword(s):  
Petroleum Hydrocarbons ◽  
Traditional Method ◽  
Oil Content ◽  
Total Petroleum Hydrocarbons ◽  
Oily Sludge ◽  
Production Plant ◽  
Liquid Ratio ◽  
Plant Oil ◽  
Standard Curve ◽  
Solid Liquid

Drained sludge of Daqing oilfield No.4 oil production plant was collected from bottoms of tanks, and the oil content was usually lower than 2%. In this paper, the contents of petroleum substances, total petroleum hydrocarbons (TPH) and animal and plant oil were investigated. Ultrasound-UV method was used to detect the oil content of oily sludge. Results showed that the best ultrasound time was 8 min and the best solid-liquid ratio for the extraction was about 1:20. The standard curve was constructed. The comparison between the ultrasound-UV method and the traditional method shows that the ultrasound-UV method is more suitable for the detection of oil content of oily sludge with lesser oil. Moreover, the methods of detecting sludge with lower oil content have been established.

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.

Improved dewatering of CEPT sludge by biogenic flocculant from Acidithiobacillus ferrooxidans

2015 ◽  
Vol 73 (4) ◽  
pp. 843-848 ◽  
Author(s):  
Jonathan W. C. Wong ◽  
Kumarasamy Murugesan ◽  
Shuk Man Yu ◽  
Mayur B. Kurade ◽  
Ammaiyappan Selvam
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Culture Medium ◽  
Specific Resistance ◽  
Primary Treatment ◽  
The Other ◽  
Organic Polymer ◽  
Drastic Reduction ◽  
Capillary Suction ◽  
Free Cells ◽  
Chemically Enhanced Primary Treatment

Bioleaching using an iron-oxidizing bacterium, Acidithiobacillus ferrooxidans, and its biogenic flocculants was evaluated to improve the dewaterability of chemically enhanced primary treatment (CEPT) sewage sludge. CEPT sludge in flasks was inoculated with A. ferrooxidans culture, medium-free cells and the cell-free culture filtrate with and without the energy substance Fe2+, and periodically the sludge samples were analysed for the dewaterability. This investigation proves that bioleaching effectively improved the sludge dewaterability as evidenced from drastic reduction in capillary suction time (≤20 seconds) and specific resistance to filtration (≥90%); however, it requires an adaptability period of 1–2 days. On the other hand, the biogenic flocculant produced by A. ferrooxidans greatly decreased the time-to-filtration and facilitated the dewaterability within 4 h. Results indicate that rapid dewatering of CEPT sludge by biogenic flocculants provides an opportunity to replace the synthetic organic polymer for dewatering.

Extracellular polymers of ozonized waste activated sludge

2001 ◽  
Vol 44 (10) ◽  
pp. 137-142 ◽  
Author(s):  
J.C. Liu ◽  
C.H. Lee ◽  
J.Y. Lai ◽  
K.C. Wang ◽  
Y.C. Hsu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Activated Sludge ◽  
Weight Distribution ◽  
Specific Resistance ◽  
Optimal Dose ◽  
Cationic Polyelectrolyte ◽  
Waste Activated Sludge ◽  
Extracellular Polymers ◽  
Capillary Suction ◽  
Ozone Dose

Effect of ozonation on characteristics of waste activated sludge was investigated in the current study. Concentrations of cell-bound extracellular polymers (washed ECPs) did not change much upon ozonation, whereas the sum of cell-bound and soluble extracellular polymers (unwashed ECPs) increased with increasing ozone dose. Washed ECPs in original sludge as divided by molecular weight distribution was 39% < 1,000 Da (low MW), 30% from 1,000 to 10,000 Da (medium MW), and 31% > 10,000 Da (high MW). It was observed that the low-MW fraction decreased, and the high-MW fraction increased in ozonized sludge. The unwashed ECPs were characterized as 44% in low MW, 30% in medium MW, and 26% in high MW. Both low-MW and medium-MW fractions of unwashed ECPs decreased while high-MW fraction increased in ozonized sludge. The dewaterability of ozonized sludge, assessed by capillary suction time (CST) and specific resistance to filtration (SRF), deteriorated with ozone dose. The optimal dose of cationic polyelectrolyte increased with increasing ozone dose. The production rate and the accumulated amount of methane gas of ozonized sludge were also higher.

Effects of calcium ion on sludge conditioning

1997 ◽  
Vol 35 (8) ◽  
pp. 217-222 ◽  
Author(s):  
Min-chao Chang ◽  
Shun-hsing Chuang ◽  
Hui-ling Lin
Keyword(s):  
Activated Sludge ◽  
Calcium Ion ◽  
Experimental Results ◽  
Capillary Suction ◽  
Polyelectrolyte Solution ◽  
Biological Sludge ◽  
Sludge Conditioning ◽  
Activated Sludge Systems

Investigating the sludge conditioning behavior and improving sludge conditionability were the primary objectives of this study. The effects of calcium ion with and without polyelectrolyte conditioning behavior on two industrially activated sludge systems were studied via Capillary Suction Time (CST) tests. Experimental results indicated that the calcium ion can strongly enhance the conditionability of the industrial biological sludge system. The good conditionability of calcium ion added system could have possibly resulted from the interaction of polysaccaride from activated sludge with calcium ion. Additionally, adding polyelectrolyte solution first would produce more suitable conditioning in a situation in which calcium ion is involved with polyelectrolyte system.

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