Investigation of electric field enhanced solid-liquid separation under various conditions /
Treatment of municipal wastewater generates huge amounts of sewage sludge, which contains large quantities of water, biomass, and extracellular polymeric substances. It is commonly known that the dewaterability of sewage sludge is poor. Usually, mechanical dewatering methods are used to reduce water...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur :
Kulliyyah of Engineering, International Islamic University Malaysia,
2015
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| Subjects: | |
| Online Access: | http://studentrepo.iium.edu.my/handle/123456789/4917 |
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| Summary: | Treatment of municipal wastewater generates huge amounts of sewage sludge, which contains large quantities of water, biomass, and extracellular polymeric substances. It is commonly known that the dewaterability of sewage sludge is poor. Usually, mechanical dewatering methods are used to reduce water content of the sludge. Nevertheless, sludge dewatering is an important monetary factor in sludge handling. High water content in the final sludge cake of wastewater treatment plants usually turns to increase transport and disposal costs as well as incineration cost. Electrodewatering is a well-known technique to enhance the solid content of the final sludge cake. But the parameters affecting the performance of electrodewatering and the quality of the resulting sludge cake, as well as removed water, are not sufficiently known. In this study for first time, numerical solution of partial differential equation, for the theoretical analysis of electroforced sedimentation (EFS) is presented. A mixture of zinc oxide (representing sludge) and polyacrylamide as a dewatering aid were used as experimental materials. The consolidation coefficient, Ce, of the material was assumed to be constant. The numerical solution can explain the solid compressive pressure distribution with time and position. The progress of electroforced sedimentation was represented by sedimentation velocity in compression settling zone. Variations of the effectiveness of EFS with constant current density, total solid volume per unit cross-sectional area and polyacrylamide dose were investigated. In this research process parameters of EFS were optimized using response surface methodology (RSM). The investigation was done by using design of experiment with face centered central composite design (FCCCD). After developing the empirical models for the output response with the three factors, optimization was done for maximum Sedimentation Velocity. The optimum values of current density, total solid volume per unit cross sectional area and polyacrylamide dose for the highest Sedimentation Velocity (0.0199 cm/min) were 6.0 A/m2, 7.74 mm and 1.53% (based on zinc oxide mass) respectively. Validation experiments were conducted to confirm and measure the accuracy of the models for three set of parameters including optimum parameters. The average percentage error for three confirmation experiments was 4.24. The error was within the limit of prediction accuracy. It can be concluded that EFS can be applied successfully for the materials which have permanent charge, and the sedimentation velocity is enhanced by the use of 1.53% polyacrylamide as dewatering aid. |
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| Physical Description: | xiv, 112 leaves : ill. ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 77-85). |