Enhancing paper sludge dewatering by waste polyester fiber and FeCl3 for preparation of Fe-rich biochar

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2326-2345
Author(s):  
Xin Zhang ◽  
Guolin Tong ◽  
Yiheng Zhou ◽  
Guoyi Li ◽  
Hui Zhang
Keyword(s):  
Extracellular Polymeric Substances ◽  
Catalytic Effect ◽  
Paper Sludge ◽  
Sludge Dewatering ◽  
Filtration Resistance ◽  
Sludge Recycling ◽  
Sludge Cake ◽  
Polyester Textile ◽  
Floc Strength ◽  
Sludge Dewaterability

The paper sludge conditioning effects of waste polyester textile fibers as skeleton builders combined with ferric chloride (FeCl3) were evaluated and the sludge dewatering mechanism was explored. The catalytic effect of Fe-rich sludge biochar (Fe-SB) on enhancing sludge dewaterability was evaluated. Results showed the combined fiber-FeCl3 conditioning significantly promoted the sludge dewaterability compared with conditioner alone, leading to a 77.5% decrease in specific filtration resistance and a 68.9% increase in net yield. The decrease of extracellular polymeric substances (EPS) contents showed that the EPS were difficult to extract and sludge floc strength was enhanced as a result of chemical reactions such as complexation processes and charge neutralization. Hence, the enhancement of sludge dewaterability was primarily due to the sludge cake with a porous and incompressible structure formed by fiber and FeCl3, and the rigidity structure of fiber. Moreover, the Fe-SB prepared by fiber-FeCl3 conditioning sludge could effectively activate persulfate to enhance the sludge dewaterability, with water content of dewatered sludge decreasing by 14.6%. The Fe-SB had dual functions of the heterogeneous catalyst of persulfate and skeleton builder. This study presents a sludge recycling method that combined physicochemical conditioning and sludge biochar materials prepared by pyrolysis.

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.

scholarly journals Synergetic Effect of Combined CaO2 and Microwave Treatment on Waste Active Sludge Dewaterability and Organic Contaminants’ Removal

2021 ◽  
Vol 9 ◽  
Author(s):  
Jie Wang ◽  
Kankan Shang ◽  
Liangjun Da ◽  
Xingguo Liu ◽  
Yongjing Zhao ◽  
...  
Keyword(s):  
Organic Contaminants ◽  
Superoxide Anion ◽  
Extracellular Polymeric Substances ◽  
Synergetic Effect ◽  
Microwave Treatment ◽  
Sludge Dewatering ◽  
Active Sludge ◽  
Capillary Suction ◽  
Contaminants Removal ◽  
Sludge Dewaterability

This study investigated the synergetic effect of the combined calcium peroxide (CaO2) and microwave (MW) treatment on waste active sludge dewatering properties and organic contaminants’ removal. The optimal sludge dewaterability was obtained at CaO2 (20 mg/gVSS)/MW (70°C), and the capillary suction time decreased by 52% compared with raw sludge. Further investigation indicated that total extracellular polymeric substances (EPS), tightly bound EPS, total protein, and protein present in tightly bound EPS were closely correlated with sludge dewaterability. Tryptophan, aromatic protein–like substances and humic acid–like substances were the key compounds that affect sludge dewaterability. The charge neutralization and bridge effect of cation ions were strengthened when combined with MW irradiation. In addition, it was revealed that MW facilitated CaO2 to produce more hydroxyl and superoxide anion radicals. This study confirmed CaO2/MW to be an effective way to improve sludge dewatering and remove organic pollutants from sludge.

Enhancement of sewage sludge dewaterability by fungal conditioning with Penicillium simplicissimum NJ12: From bench- to pilot-scale consecutive multi-batch investigations

2021 ◽  
Author(s):  
Neng Tao ◽  
Xiu Wu ◽  
Feng Zhang ◽  
Zilei Pi ◽  
Jiaqi Wen ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Volume Fraction ◽  
Linear Regression Analysis ◽  
Pilot Scale ◽  
Recycling Rate ◽  
Penicillium Simplicissimum ◽  
Fungal Treatment ◽  
Sludge Dewatering ◽  
Capillary Suction ◽  
Sludge Dewaterability

Abstract Bench- and pilot-scale successive multi-batch trials were conducted to investigate the performance and sustainability of fungal conditioning with Penicillium simplicissimum NJ12 for improving sludge dewatering. The dominant factors affecting the sludge dewaterability improvement by P. simplicissimum NJ12 were also identified. Fungal treatment with P. simplicissimum NJ12 at a volume fraction of 5% of the inoculum greatly improved the sludge dewaterability. This improvement was characterized by sharp decreases in the specific resistance to filtration from 1.97 × 1013 to 3.52 × 1011 m/kg and capillary suction time from 32 to 12 s within 3 days. Stepwise multiple linear regression analysis showed that a marked decrease (58.8%) in the protein content in slime extracellular polymeric substances and an increase in the zeta potential of the sludge (from − 35 to − 10 mV) were the most important factors that improved the dewaterability of sludge after fungal treatment. Consecutive processes of fungal treatment could be realized by recirculating the fungal-treated sludge with a recycling rate of 1:2 (Vbiotreated sludge/Vtotal sludge). The treatment effectiveness was maintained only over three successive cycles, but replenishment with fresh P. simplicissimum NJ12 would be provided periodically at set batch intervals. These findings demonstrate the possibility of P. simplicissimum NJ12-assisted fungal treatment for enhancing sludge dewatering.

A laboratory sludge press for characterizing sludge dewatering

1997 ◽  
Vol 35 (2-3) ◽  
pp. 189-196 ◽  
Author(s):  
T. Rehmat ◽  
R. Branion ◽  
S. Duff ◽  
M. Groves
Keyword(s):  
Flow Rate ◽  
Applied Pressure ◽  
Screw Press ◽  
Laboratory Scale ◽  
Sludge Dewatering ◽  
Mill Scale ◽  
Filtration Resistance ◽  
Secondary Sludge ◽  
Sludge Cake ◽  
Press Time

A laboratory scale sludge press is described. Its use in measuring the specific filtration resistance of a slurry is outlined. The effects of applied pressure and press time on filtrate flow rate and sludge cake solids are discussed as are the effects of various combinations of primary and secondary sludge. Its use in optimizing the polymer formulation for improved dewaterability of sludge in a screw press is detailed. Comparisons of laboratory sludge press predictions and the results of mill scale screw press and belt filter trials are presented.

scholarly journals Evaluation of hydrophobically associating cationic starch-based flocculants in sludge dewatering

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pan Hu ◽  
Shaohang Shen ◽  
Hu Yang
Keyword(s):  
Extracellular Polymeric Substances ◽  
Synergistic Effects ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Structural Factors ◽  
Cationic Starch ◽  
Sludge Dewatering ◽  
Sludge Flocs ◽  
Structure Activity ◽  
Sludge Dewaterability

AbstractTwo series of binary graft cationic starch-based flocculants (CS-DMCs and CS-DMLs) with different hydrophilicity and charge density (CD) were prepared by graft copolymerization of acrylamide with 2-(Methacryloyloxy)-N,N,N-trimethylethanaminium chloride and methacrylic acid 2-(benzyldimethylaminio) ethyl chloride, respectively, on the starch (St) backbone. The sludge dewatering performance of CS-DMCs and CS-DMLs were evaluated and compared based on the changes in filter cake moisture content (FCMC), specific resistance of filtration (SRF), fractions and components of extracellular polymeric substances, and various physiochemical characteristics of sludge flocs and cakes. Increase in CD of the St-based flocculants caused improved sludge dewaterability. Under the similar CD, CS-DML with relatively high hydrophobicity exhibited lower FCMC and SRF, larger and denser sludge flocs, and better permeability of sludge cakes than CS-DMCs due to the synergistic effects of charge neutralization, bridging flocculation and hydrophobic association. Furthermore, a second-order polynomial model on the basis of phenomenological theory was successfully applied to quantitatively evaluate the influences of the two important structural factors of these St-based flocculants, i.e., hydrophobicity and CD, on the sludge dewaterability. The structure–activity relationship of the St-based flocculants in sludge dewatering was obtained according to the theoretic simulation. The dewatering mechanisms was discussed in depth on the basis of the experimental and simulated results; besides, the FCMC and optimal dose can be predicted by the established structure–activity relationship. This current work offered a novel and valuable way to exploit and design of low-cost and high-performance graft natural polymeric flocculants applied in efficient conditioning of sludge.

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.

Freeze–thaw combined with activated carbon improves electrochemical dewaterability of sludge: Analysis of sludge floc structure and dewatering mechanism

2021 ◽  
Author(s):  
Kai Hui ◽  
Lei Song ◽  
Zhenzhou Yin ◽  
Hongwei Song ◽  
Zehao Wang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Extracellular Polymeric Substances ◽  
Combined Treatment ◽  
Electrochemical Treatment ◽  
Sludge Dewatering ◽  
Element Analysis ◽  
Sludge Flocs ◽  
Freeze Thaw ◽  
Floc Structure ◽  
Sludge Cake

Abstract Freeze–thaw (F/T) and electrochemistry are environment-friendly and efficient sludge treatment technologies. In this study, F/T and electrochemistry were combined in the pretreatment of sludge dewatering in the laboratory, and activated carbon (AC) was added to improve the electrochemical dewatering performance of sludge. During the experiment, the effect of F/T on the floc structure was analyzed by a laser particle analyzer and scanning electron microscope. F/T treatment not only improved the dewatering performance of sludge, but also promoted the aggregation of sludge flocs into larger particles. The median diameter (D50) increased from 45.27 µm to 128.94 µm. Then, the intracellular polymer of large-particle sludge was analyzed by three-dimensional excitation–emission matrix (3D-EEM). The tightly bound extracellular polymeric substances (TB-EPS) still contained a large amount of protein substances, which hindered the improvement of sludge dewatering performance. AC was added to the thawed sludge solution before electrochemical treatment (EP). The conductivity of AC enhanced the effect of EP, thereby cracking the sludge flocs. Thus, the light intensity of TB-EPS in the 3D-EEM fluorescence spectroscopy was decreased, and the D50 was also reduced to 105.3 µm. The final specific resistance of filtration and water content were reduced by 96.39% and 32.17%, respectively. Element analysis of the sludge cake after dehydration showed that the addition of AC significantly improved the combustion efficiency of the sludge cake. Moreover, preliminary economic analysis showed that the cost of this research was low, which indicated the potential application value of combined treatment.

Effect of using different proportions of inoculum during bioleaching on sludge dewaterability

2018 ◽  
Vol 2017 (3) ◽  
pp. 802-811 ◽  
Author(s):  
Qingfang Zhang ◽  
Wenfeng Yang ◽  
Qiyong Yang ◽  
Tianfeng Wang ◽  
Shenliang Chen ◽  
...  
Keyword(s):  
Crucial Role ◽  
Extracellular Polymeric Substances ◽  
Reduction Potential ◽  
Specific Resistance ◽  
Sludge Dewatering ◽  
Capillary Suction ◽  
Geological Materials ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Sludge Dewaterability

Abstract Bioleaching, the addition of bacteria to geological materials, has been applied to sludge to remove metals and improve upon sludge dewaterability. This paper investigates the effect of using different quantities of inoculum (bacteria) during bioleaching on sludge dewaterability. The analysis was based on bioleaching experiments conducted in a 20 L bio-reactor using different quantities of inoculum (20%, 10%, 5%, 2%, 0%). Changes in pH, oxidation reduction potential (ORP), capillary suction time (CST), specific resistance to filtration (SRF) and extracellular polymeric substances (EPS) were determined to gauge sludge dewatering. Results indicate that sludge dewaterability during the 2%, 10%, and 20% inoculum experiments declined through time. Decreased dewaterability is attributed to increases in the quantity of proteins and polysaccharides in slime EPS. Dewaterability improved during the 5% inoculum experiment, and reached a maximum when pH was 2.3. During this latter experiment, CST and SRF were reduced by 74% and 62%, respectively, in comparison to control conditions, while total EPS content decreased by 71%. The decrease in total EPS was primarily due to a decrease in proteins associated with tightly bound EPS (TB-EPS). Thus, changes in the amount of proteins in TB-EPS and sludge pH played a crucial role in sludge dewaterability.

scholarly journals Use of a water treatment sludge in a sewage sludge dewatering process

2018 ◽  
Vol 30 ◽  
pp. 02006 ◽  
Author(s):  
Justyna Górka ◽  
Małgorzata Cimochowicz-Rybicka ◽  
Małgorzata Kryłów
Keyword(s):  
Water Treatment ◽  
Sewage Sludge ◽  
Research Study ◽  
Water Treatment Sludge ◽  
Sludge Dewatering ◽  
Capillary Suction ◽  
Filtration Resistance ◽  
Future Studies ◽  
Volatile Solids ◽  
Sludge Dewaterability

The objective of the research study was to determine whether a sewage sludge conditioning had any impact on sludge dewaterability. As a conditioning agent a water treatment sludge was used, which was mixed with a sewage sludge before a digestion process. The capillary suction time (CST) and the specific filtration resistance (SRF) were the measures used to determine the effects of a water sludge addition on a dewatering process. Based on the CST curves the water sludge dose of 0.3 g total volatile solids (TVS) per 1.0 g TVS of a sewage sludge was selected. Once the water treatment sludge dose was accepted, disintegration of the water treatment sludge was performed and its dewaterability was determined. The studies have shown that sludge dewaterability was much better after its conditioning with a water sludge as well as after disintegration and conditioning, if comparing to sludge with no conditioning. Nevertheless, these findings are of preliminary nature and future studies will be needed to investigate this topic.

Filtration resistance induced by ammonia oxidizers accumulating on the rotating membrane disk

1998 ◽  
Vol 38 (4-5) ◽  
pp. 443-452
Author(s):  
Katsuki Kimura ◽  
Yoshimasa Watanabe ◽  
Naoki Ohkuma
Keyword(s):  
Membrane Filtration ◽  
Extracellular Polymeric Substances ◽  
Drinking Water Treatment ◽  
Treatment Method ◽  
Operating Conditions ◽  
Transmembrane Pressure ◽  
Ammonia Oxidizers ◽  
Filtration Resistance ◽  
Rotating Membrane Disk ◽  
Membrane Disk

Membrane filtration and oxidation of ammonia were simultaneously performed by using a rotating membrane disk module. Nitrification performance, composition of the accumulated cakes on the membrane and the filtration resistances were investigated under five different operating conditions. The filtration resistance due to the accumulated cake on the membrane was found to be dominant in this treatment method, compared to the resistance due to the micropore plugging or irreversible adherence. The cake consisted mainly of iron, humic substances and bacteria. The possibility that extracellular polymeric substances were related to the cake resistance was also shown. The composition of the cake depended on the length and the condition of operation. Accumulation of ammonia oxidizers caused by oxidation of low concentrations of ammonia (less than 1 mg/l) did not increase transmembrane pressure significantly. Therefore, the application of this treatment method for drinking water treatment is feasible. Filtration resistance due to the micropore plugging or irreversible adherence to the membrane was caused by organic substances.

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