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.

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.

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.

scholarly journals Effect of Injection Flow Rate on Product Gas Quality in Underground Coal Gasification (UCG) Based on Laboratory Scale Experiment: Development of Co-Axial UCG System

Energies ◽  
2017 ◽  
Vol 10 (2) ◽  
pp. 238 ◽  
Author(s):  
Akihiro Hamanaka ◽  
Fa-qiang Su ◽  
Ken-ichi Itakura ◽  
Kazuhiro Takahashi ◽  
Jun-ichi Kodama ◽  
...  
Keyword(s):  
Flow Rate ◽  
Coal Gasification ◽  
Laboratory Scale ◽  
Underground Coal Gasification ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
Product Gas ◽  
Scale Experiment

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.

scholarly journals Preparation of electrospun nanofiber membrane for air filtration and process optimization based on BP neural network

2021 ◽  
Author(s):  
Le Kang ◽  
Yuankun Liu ◽  
Liping Wang ◽  
Xiaoping Gao
Keyword(s):  
Neural Network ◽  
Quality Factor ◽  
Flow Rate ◽  
Bp Neural Network ◽  
Polyvinylidene Fluoride ◽  
Orthogonal Experiment ◽  
Solution Concentration ◽  
Filtration Efficiency ◽  
Air Filtration ◽  
Filtration Resistance

Abstract The filtration layer in a medical protective mask can effectively prevent aerosol particles that might carry viruses from air. A nanofiber/microfiber composite membrane (NMCM) was successfully fabricated by electrospinning polyvinylidene fluoride (PVDF) nanofibers collected on the electrified and melt-blown polypropylene (PP) nonwovens, aiming to improve the filtration efficiency and reduce the resistance of respiration of mask. A four-factor and three-level orthogonal experiment was designed to study the effect of electrospinning parameters such as spinning solution concentration, voltage, tip-collect distance (TCD), and flow rate of solution on the filtration efficiency, resistance of respiration as well as quality factor of NMC developed to predict the resistance of respiration. Experimental results demonstrated that the filtration efficiency of NMCM≥95% in comparison to that of electrified and melt-blown PP nonwovens 79.38%, which increases by 19.68%. Additionally, the average resistance of respiration is 94.78 Pa, which meets the protection requirements. Multivariate analysis of variance indicated that the resistance of respiration of the NMCM has significantly dependent on the concentration, voltage, TCD, and flow rate of the spinning solution and the quality factor of the NMCM has dependent on the resistance of respiration. The air permeability ranges from 166.23 to 314.35mm/s, which is inversely proportional to the filtration resistance. As far as the filtration resistance is concerned, the optimal spinning parameters were obtained as follows. The concentration of spinning solution is 15%, the voltage is 27 kV, the TCD is 22 cm, and the flow rate is 2.5 mL/h. The relative error of the BP neural network varies from 0.49505% to 1.49217%, i.e. the error value varies from 0.17 to1.33 Pa. The predicted resistance of respiration corresponding to the optimal process is 68.1374 Pa.

scholarly journals Production Efficiency of Enbal (Cassava) Using Hydraulic Press Equipment in the Enbal Processing Group in Ibra Village, Southeast Maluku Regency

2020 ◽  
Vol 13 (2) ◽  
pp. 378
Author(s):  
Ismael Marasabessy ◽  
Fien Sudirjo ◽  
Syahibul K. Hamid ◽  
Yuni Irmawaty
Keyword(s):  
Production Process ◽  
Production Efficiency ◽  
Hydraulic Press ◽  
Screw Press ◽  
Training Techniques ◽  
Sanitation And Hygiene ◽  
Three Stages ◽  
Press Equipment ◽  
Press Time ◽  
Processing Group

The business group which is become the target of this activity is a group of processing and selling enbal (cassava) in Ibra village, Southeast Maluku regency. This group has been producing for more than 10 years but there are still many shortage, especially in the way of press along with the sanitize and hygiene of the production process. The purpose of this activity is to increase the efficiency in production process by applying screw press equipment and improving sanitation and hygiene in its production. The method of implementing activities uses discussion and training techniques. The activity is carried out in three stages, firstly survey on condition and discussion with partners relates to the conditions of producing pressing enbal, secondly the manufacture of pressing tools, third is the application of pressing tools in production activities of partners. The results of the activity showed that the screw press was able to produce enough water of enbal / grated cassava so that it is drier than the traditional method. Press time becomes faster which only 12-15 minutes, whereas in the traditional way it takes 14-24 hours. The content of enbal’s water decreases very low, reaching 5-7%, the sanitation becomes better because the juice is no longer stagnant on the ground but is collected in a bucket, and the use of pressing tools is very practical. Likewise the HCN level is very low, less than 3mg / kg so the product is very safe for consumption. This screw press is very helpful in the efficiency of the production process of plate enbal (cassava plates) which is cleaner and healthier.

scholarly journals A Hybrid Computational and Analytical Model of Inline Drip Emitters

2018 ◽  
Author(s):  
Jaya Narain ◽  
Amos G. Winter
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Flow Behavior ◽  
Applied Pressure ◽  
Computational Time ◽  
Matrix Formulation ◽  
Element Analysis ◽  
Line Load ◽  
Variable Resistor ◽  
Constant Flow Rate

This paper details a hybrid computational and analytical model to predict the performance of inline pressure-compensating (PC) drip irrigation emitters. The term inline refers to flow control devices mounted within the irrigation tubing. Pressure-compensating emitters deliver a relatively constant flow rate over a range applied pressure to accurately meter water to crops. Flow rate is controlled within the emitter by directing the water through a tortuous path (which imposes a fixed resistance), and then through a variable resistor composed of a flexible membrane that deflects under changes in pressure, restricting the flow path. An experimentally validated computational fluid dynamics (CFD) model was used to predict flow behavior through tortuous paths, and a pressure resistance parameter was derived to represent the pressure drop with a single variable. The bending and shearing mechanics of the membrane were modeled analytically and refined for accuracy by deriving a correction factor using finite element analysis. A least-squares matrix formulation that calculates the force applied by a line load of any shape, along which there is a prescribed deflection applied on a rectangular membrane, was derived and was found to be accurate to within one percent. The applicability of the assumption of locally fully developed flow through the pressure compensating chamber in a drip emitter was analyzed. The combined hybrid computational-analytical model reduces the computational time of modeling drip emitter performance from days to less than 30 minutes, dramatically lowering the time required to iterate and select optimal designs. The model was validated using three commercially available drip emitters, rated at 1.1, 2, and 3.8 L/hr. For each, the model predicted the flow rate with an error of twenty percent or less, as compared to the emitter performance published by the manufacturer.

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