| Summary: | 碩士 === 朝陽科技大學 === 環境工程與管理系碩士班 === 100 === The study examines the effectiveness of sludge dewatering using filter presses in Feng Yuan Purification Plant of Taiwan Water Corporation. By installing an experimental filter press and using polypropylene filters, the study tries to remove the liquid from liquid-solid sludge containing 5%, 10%, 15% and 37.3% solids for 30, 60 and 90 minutes by batch conditioning. The pressure is set at 5.5 kg/cm2 with the voids between plates(filter chambers) measuring 2.5cm, 3.0 cm, 3.5cm, 4.0 cm and 4.5 cm respectively. The study observes the filtrate, the weight and moisture content of each filter cake to investigate the influence of parameters of a filter press on the production and the moisture content of filter cakes. Based on the results of the first phase of the experiment, another void between plates(filter chambers) measuring 3.5 cm is designed for pressure tests with fabric filters of low permeability and high permeability. The pressure is set at 4 kg/cm2, 5.5 kg/cm2, and 7 kg/cm2 respectively to dewater liquid-solid sludge containing 29.94% solids by continuous feeding for the observation of the influence of pressure on the weight and moisture content of filter cakes.
The first phase of the experiment indicates that a narrow void between plates(filter chamber) measuring 2.5cm and the pressure setting at 60 minutes give the best dewatering efficiency for sludge containing a lower percentage of solids of 5%, 10%, 15%. On the other hand, when sludge contains solids up to 37.3%, good filter cakes with low moisture content can be produced by a wide void measuring 4.5 cm and the pressure setting of 30 min.
We conduct pressure tests with polypropylene filters with different permeability and summarize views of the filters under the microscope at 400 times of magnification. Take 1000 L of filtrate from the first batch of condition for particle size distribution by LASER diffraction. The results show that polypropylene filters with large mesh size and low permeability facilitate better dewatering than those with small mesh size and high permeability.
The second phase pressure tests indicates that the increased pressure from 4 kg/cm2 to 7 kg/cm2 help add the weight and reduce the moisture content of filter cakes.
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