Dual-conditioning of sludge using chitosan and metal cations

2015 ◽  
Vol 10 (2) ◽  
pp. 381-389 ◽  
Author(s):  
S. W. Lau ◽  
S. D. Tang ◽  
H. M. Ang ◽  
T. K. Sen ◽  
H. B. Chua
Keyword(s):  
Metal Cations ◽  
Surface Charges ◽  
Sludge Dewatering ◽  
Salting Out ◽  
Simultaneous Application ◽  
Capillary Suction ◽  
Sludge Cake ◽  
Negative Surface ◽  
Sludge Conditioning ◽  
Time Specific

Sludge dewatering is important in sludge management and disposal. In practice, chemical conditioners are often introduced to aid sludge dewatering. This study investigated the simultaneous application of chitosan and metal cations as dual-conditioners to improve sludge dewaterability. The dewatering performance of sludge was evaluated using three common measurements, i.e. capillary suction time, specific resistance to filtration, and moisture content of the filtered sludge cake. The effectiveness of metal cations in sludge conditioning and dewatering was found, in ascending order, to be Na+ < K+ ≈ Mg2+ < Ca2+ < Al3+ < Fe3+. Dual-conditioning using chitosan and metal cations further enhanced dewaterability. Cations may have significant effects on sludge conditioning by neutralization of negative surface charges, bridging of floc components, and the salting out effect, leading to improved dewaterability when used in conjunction with chitosan.

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.

A New Sensing Technique for Optimum Sludge Conditioning for Waste Sludge Dewatering

1993 ◽  
Vol 28 (11-12) ◽  
pp. 481-488 ◽  
Author(s):  
Y. Yasukawa ◽  
T. Totoki ◽  
H. Shigemi
Keyword(s):  
Moisture Content ◽  
Laboratory Test ◽  
Sludge Dewatering ◽  
Film Sensor ◽  
Waste Sludge ◽  
Sludge Cake ◽  
Sludge Dewaterability ◽  
Sludge Conditioning ◽  
Hot Film ◽  
Hot Film Sensor

A new sensing technique using a Hot-Film sensor for determining the optimum polymer dosage for sludge dewatering has been developed. Correlations between the behavior of the Hot-Film sensor and dewaterability of sewage and night soil sludge were investigated. The results of the study revealed the following: the Hot-Film sensor values depended on the filtrate characteristics related to the sludge dewaterability which is measured by the filterability of the conditioned sludge and by the moisture content of the dewatered sludge cake; the optimum polymer dosage for sludge dewatering corresponded with the minimum output value on the characteristics curve of the Hot-Film sensor. This paper describes the observations of the measurement test by the Hot-Film sensor as well as the results of the laboratory test of sludge dewatering for optimum sludge conditioning.

scholarly journals Effects of Moringa Peregrina and Ferric Chloride (FeClƒ ) On Water Treatment Sludge Dewatering

2018 ◽  
Vol 15 (4) ◽  
pp. 975-980 ◽  
Author(s):  
Ramtin Mazaheri ◽  
Mostafa Tizghadam Ghazani ◽  
Abolghasem Alighardashi
Keyword(s):  
Water Treatment ◽  
Moisture Content ◽  
Ferric Chloride ◽  
Optimum Dose ◽  
Water Treatment Sludge ◽  
Sludge Dewatering ◽  
Capillary Suction ◽  
Cake Moisture ◽  
Sludge Cake ◽  
Conditioning Effect

In the present study, an active component of Moringa peregrine (MP) was used in comparison with ferric chloride (FeCl₃) for the conditioning of water treatment sludge. The comparison was based on dewatering characteristics of the conditioned sludge determined by capillary suction time (CST), specific resistance to filtration (SRF), tests of time of filtration (TTF) and sludge cake moisture content. The results indicated that MP showed relatively comparable conditioning effect as ferric chloride. Sludge conditioned with ferric chloride, showed better results than MP. According to CST, SRF and tests of time of filtration (TTF) and sludge cake moisture content results, optimum dose for MP, and ferric chloride was 100 ml/l. From the results of the study it could be concluded that MP alone could be effectively used and replace ferric chloride for dewatering of water treatment sludge.

scholarly journals Perception on aggregation induced multicolor emission and emission centers in carbon nanodots using successive dilution, anion exchange chromatography, and multi-way statistics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohsen Kompany-Zareh ◽  
Saeed Bagheri
Keyword(s):  
Anion Exchange ◽  
Quantum Confinement Effect ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Carbon Nanodots ◽  
Surface Charges ◽  
Negative Surface ◽  
Amine Groups ◽  
Optical Behavior ◽  
Optical Structure

AbstractExploration in the way of understanding the optical behavior and structure of carbon nanodots has been increased due to their vast application. Their emission dependency on excitation wavelengths is the more prevalent and controversial subject. In this report we considered the optical structure of hydrothermally synthesized carbon nanodots using citric acid and 2,3-diaminopyridine as precursors. The presence of different emission centers experimented through anion exchange chromatography which resulted in fractions with more unique optical structures. The quantum confinement effect and energy exchange between different types of carbon nanodots, due to aggregation in higher concentration levels, was studied applying a stepwise dilution experiment. Analysis of the experimental data was done through the parallel factor analysis and the trajectory pattern recognition which resolved more about optical interactions and the presence of different emission centers in different particles. Results from infrared spectroscopy confirmed the dominating density of carboxyl functional groups on the nanodots with negative surface charges and higher influence of amine groups on dots with positive surface charges.

Effects of potassium ion on sludge settling, dewatering and effluent properties

1998 ◽  
Vol 37 (4-5) ◽  
pp. 317-324 ◽  
Author(s):  
Sudhir N. Murthy ◽  
John T. Novak
Keyword(s):  
Activated Sludge ◽  
Field Studies ◽  
Potassium Ion ◽  
Potassium Ions ◽  
Nutrient Requirements ◽  
Sludge Dewatering ◽  
Capillary Suction ◽  
Sludge Flocs ◽  
Sludge Properties ◽  
Sludge Settling

Potassium ions appear to play an important role in determining the nature of activated sludge flocs. Relative to sodium, the concentration of potassium ions in most industrial activated sludge is typically low. Laboratory and field studies were conducted to examine the influence of potassium on activated sludge properties. The concentration of potassium affected the concentration of readily extractable (slime) proteins in the floc and the proteins in the surrounding solution. In laboratory tests, an increase in this cation's concentration beyond nutrient requirements impeded sludge dewatering properties as measured by capillary suction time (CST) and specific resistance to filtration (SRF) and associated with an increase in soluble protein. An increase in effluent total organic carbon and effluent turbidity was observed at higher concentrations of this ion. Conversely, an increase in concentration of potassium ion improved the settling properties of sludge with low equivalent monovalent to divalent cation ratio.

Extraction of chloride acido complexes of triply charged metal cations in water–oxyethylated nonylphenol–salting-out agent systems

2018 ◽  
Vol 67 (9) ◽  
pp. 1608-1611 ◽  
Author(s):  
A. V. Stankova ◽  
A. M. Elokhov ◽  
S. A. Denisova ◽  
A. E. Lesnov
Keyword(s):  
Metal Cations ◽  
Salting Out ◽  
Agent Systems

scholarly journals Brief communication: The influence of mica-rich rocks on the shear strength of ice-filled discontinuities

2020 ◽  
Vol 14 (6) ◽  
pp. 1849-1855
Author(s):  
Philipp Mamot ◽  
Samuel Weber ◽  
Maximilian Lanz ◽  
Michael Krautblatter
Keyword(s):  
Shear Strength ◽  
Failure Criterion ◽  
Rock Slopes ◽  
Surface Charges ◽  
Permafrost Rock ◽  
Rock Types ◽  
Negative Surface ◽  
The Stability ◽  
Stress Dependent ◽  
Dependent Failure

Abstract. A temperature- and stress-dependent failure criterion for ice-filled rock (limestone) joints was proposed in 2018 as an essential tool to assess and model the stability of degrading permafrost rock slopes. To test the applicability to other rock types, we conducted laboratory tests with mica schist and gneiss, which provide the maximum expected deviation of lithological effects on the shear strength due to strong negative surface charges affecting the rock–ice interface. Retesting 120 samples at temperatures from −10 to −0.5 ∘C and normal stress of 100 to 400 kPa, we show that even for controversial rocks the failure criterion stays unaltered, suggesting that the failure criterion is transferable to mostly all rock types.

Pre-selection of flocculants by the LUMiFuge separation analyser 114

2002 ◽  
Vol 46 (4-5) ◽  
pp. 441-446 ◽  
Author(s):  
T. Sobisch ◽  
D. Lerche
Keyword(s):  
Dynamic Behaviour ◽  
Test Procedure ◽  
Centrifugal Acceleration ◽  
Sludge Dewatering ◽  
Total Solids ◽  
Shear Sensitivity ◽  
Compression Behaviour ◽  
Sludge Cake ◽  
Kinetics Of ◽  
Selection Of

This paper reports on lab-scale investigations in relation to pre-selection of flocculants for sludge dewatering with decanter centrifuges. Results obtained were compared with CST-measurements and discussed in relation to findings under field conditions. Experiments were carried out with sewage sludges of different origin and characteristics and a number of commercial flocculants. Kinetics of sedimentation and clarification were measured as well as the compression behaviour and shear sensitivity of sludge sediments. To measure flocculant performance stability against intensive shearing, total solids in the sludge cake obtained and dewaterability of the sludge cake during the first 20-50 s of centrifugation were compared. A screening test procedure was developed. Efficient flocculants should produce high residual total solids and good initial compressibility. Lab-scale investigations deliver more reliable results if the dynamic behaviour of the sludge under centrifugal acceleration is also investigated. The separation analyser LUMiFuge 114 can provide results about the compression behaviour of sludges in the range between 10 and 100 s. So far no other method or device is known which can deliver such results.

Study on the effect of chitosan conditioning on sludge dewatering

2019 ◽  
Vol 79 (3) ◽  
pp. 501-509 ◽  
Author(s):  
Jin Zhang ◽  
Qing Hu ◽  
Jie Lu ◽  
Shuang Lin
Keyword(s):  
Moisture Content ◽  
Extracellular Polymeric Substances ◽  
Waste Water Treatment ◽  
Sewage Treatment ◽  
Organic Polymer ◽  
Sludge Dewatering ◽  
Sludge Treatment ◽  
Residual Sludge ◽  
Sludge Cake ◽  
Polymer Flocculant

Abstract The difficulty of residual sludge dehydration is the major problem in sewage treatment. The reduction of moisture content in sludge can reduce the sludge volume significantly and is conducive to the subsequent disposal of sludge. As an organic polymer flocculant, chitosan (CTS) is widely used in water and waste water treatment. In this study, CTS was used in sludge treatment to improve the sedimentation and dehydration properties of sludge. When treated with CTS, the moisture content of sludge cake decreased from 85.9% to 83.0%, the SV30 decreased to about 1/2, and the sludge volume reduced to 82.9%. Further analysis showed that the zeta potential (ζ-potential) of the sludge changed from negative value to positive value, and the D50 of the sludge was larger than that of the raw sludge. In addition, when the moisture content of the sludge cake was reduced to the lowest, the concentration of extracellular polymeric substances (EPS) and SCOD was the largest and the |ζ| decreased to the lowest. CTS improved the dehydration and sedimentation performance of sludge mainly by factors of electrical neutralization, adsorption bridging and dissolution of EPS.

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