scholarly journals New Screw Press Sludge Dewatering Equipment. Reduction of Sludge Moisture Content with a Minimum of Operator Maintenance.

1997 ◽  
Vol 51 (2) ◽  
pp. 351-356
Author(s):  
Takesi Okada
1990 ◽  
Vol 22 (12) ◽  
pp. 153-161 ◽  
Author(s):  
Maryla Smollen

A number of parameters that influence sludge dewatering behaviour have been identified, but there is a lack of consensus which of these are of the greatest concern in sludge treatment strategies. Moisture retention characteristics were obtained from vacuum drying of centrifuged sludge samples to subdivide moisture into immobilised, physically and chemically bound fractions. Physically bound moisture is responsible for unsatisfactory dewatering by centrifugation. Polyelectrolyte releases some of the immobilised water, but simultaneously increases the physically bound moisture content which gives rise to large energy inputs during mechanical dewatering. Commonly used dewaterability measurements do not appear to be linked to moisture retention characteristics.


2019 ◽  
Vol 79 (3) ◽  
pp. 501-509 ◽  
Author(s):  
Jin Zhang ◽  
Qing Hu ◽  
Jie Lu ◽  
Shuang Lin

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.


Author(s):  
S. S. Dryabina ◽  
A. V. Navrotskiy ◽  
J. N. Malysheva ◽  
I. A. Novakov

The processes of activated sludge dewatering using cationic flocculants and their binary mixtures have been investigated, recommendations have been developed for improving the technology of sludge dewatering. The results of tests to identify the optimal ratios of flocculants in the mixture during compaction and dehydration of activated sludge sludge are given, the concentration range is determined. It is shown that the use of binary mixtures of cationic flocculants makes it possible to reduce the moisture content of the sediment and reduce the content of suspended solids in the filtrate while simultaneously reducing the dose of polyelectrolytes.


1997 ◽  
Vol 35 (2-3) ◽  
pp. 189-196 ◽  
Author(s):  
T. Rehmat ◽  
R. Branion ◽  
S. Duff ◽  
M. Groves

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.


Author(s):  
Yuli Setyo Indartono ◽  
Heriawan Heriawan ◽  
Ika Amalia Kartika

The oil extraction of Calophyllum seeds using a conventional single screw press leads to an inferior yield and is perceived to be less efficient as well as difficult to operate. An innovative and flexible single screw press was, therefore, designed and investigated in this study to solve these problems. Moreover, the effects of the seeds’ moisture content, pressing temperature and seeds’ feed rate on the oil yield and quality were identified to determine the optimal oil extraction performance from the Calophyllum seeds. The study found that the seeds’ moisture content, pressing temperature and seeds’ feed rate generally affected the oil yield. The yield indeed improved as the pressing temperature and the seeds’ feed rate increased respectively from 45 to 75°C and 1.5 to 5 kg·h<sup>–1</sup>. The oil yield also ameliorated as the seeds’ moisture content rose from 1.7 to 12.8%, but it was optimal when the seeds’ moisture content was 5.5%. The best oil yield of 80.6% was, thus, obtained with the seeds’ moisture content of 5.5%, a pressing temperature of 75°C and the seeds’ feed rate of 5 kg per h. Although the quality of the crude oil was poor with a high viscosity (³ 94 mm<sup>2</sup>·s<sup>–1</sup>) and high acid value (³ 48 mg KOH/g), its density, saponification and iodine values were acceptable. After the oil refining process by degumming and neutralisation, its quality improved and met the Indonesian Biofuel Standards, except for its viscosity.


Author(s):  
George Y. Obeng ◽  
Michael K Adjaloo ◽  
Peter Donkor

The purpose of this study is to establish optimum extraction temperature, moisture content, particle size and the effect of roasting of shea kernels on extraction efficiency for optimum shea butter yield using low pressure (45kg/cm2) manual screw press. Extraction of shea butter is a major income generating activity in Ghana, particularly in the Northern Regions. It is estimated that about 80% of the shea butter produced in Ghana is processed by women using traditional aqueous extraction method. Commercial extraction using continuous screw press accounts for about 20% of production. Oil extraction rates for the traditional aqueous extraction method are relatively low. The traditional aqueous method involves roasting, milling, creaming and boiling, and relies on very low pressure, high moisture of 65-68% and temperatures of 100-140°C. In this study Intermediate Moisture Content (IMC) method was employed. The IMC method involves the use of a low pressure manual screw press to extract butter from shea kernels. The study established an optimum extraction temperature of 60°C and moisture content of 12% at which butter extraction efficiency was between 65.9% and 68.5%. The results revealed that oil extraction efficiency depends on the fineness of paste to be processed and that roasted kernels do not give higher butter yield than unroasted kernels. This is against the traditional belief that high shea butter yield can only be achieved when the kernels are roasted.


2021 ◽  
Author(s):  
Xuan Huan Nguyen ◽  
Thi Thuy Pham ◽  
Thi Thanh Huyen Dang ◽  
Thi Ngoc Lan Pham ◽  
Thuy Anh Tran ◽  
...  

Abstract With the increasing wastewater generation from domestic and industrial activities due to the rapid economic development, the generation of sludge, in particular dredged sludge from municipal sewer system, has been an issue in developing countries. This study evaluated the enhancement of sewer’s sludge dewatering via mixing the sludge with different agro-wastes, including corn core powder, rice husk powder, bagasse powder and peanut shell powder. The addition of these agro-waste powders helped decrease the sludge’s moisture contents up to 17% after mixing with the ratio of 1:3, 1:5 or 1:7. Statistical analysis revealed the impacts of both additive types and mixing ratio on moisture content reduction. Among the four types of agro-waste, rice husk was shown to be the best additive to dredge sludges with highest reduction of heavy metal concentration and moisture content. The addition of agro-waste powders to enhance the dewatering of sludges is quite promising in the context of promoting waste reuse and energy saving.


1993 ◽  
Vol 28 (11-12) ◽  
pp. 481-488 ◽  
Author(s):  
Y. Yasukawa ◽  
T. Totoki ◽  
H. Shigemi

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.


1989 ◽  
Vol 21 (10-11) ◽  
pp. 1441-1446
Author(s):  
Earl W. Knight

The present sludge processing operations at the District consist of heated anaerobic digestion, dewatering by centrifugation, and air drying. A critical unit operation in the overall sludge processing train is the mechanical dewatering step. Typically, sludge dewatering by the District's existing centrifuges produces a cake having a solids content of 15%. Four different types of mechanical sludge dewatering machines were evaluated in a pilot test program to determine if these machines could produce cakes having greater solids contents than that produced from the existing centrifuges. The machines tested were two modified versions of the conventional horizontal solid bowl centrifuge design, a screw press, and a diaphragm filter press. The two modified centrifuges produced cakes having average solids contents of 20% and 29.4%, respectively; the screw press produced a cake having an average solids content of 17.5%, and the diaphragm filter press produced a cake having an average solids content of 29.4%. Based on the pilot test program, a test evaluation program was conducted using full-scale centrifuge machines of the modified designs. The preliminary results of this test program confirmed that centrifuges can produce a cake with a solids content approximately equal to or greater than 30%.


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