A filtration system in a water treatment plant consists of four (4) filter boxes of the size = 45m^2 design flow= 40000 m^3/d, also obtained from Table 2.1. The filter bed is uniform with particles of size 0.50 mm, with specific gravity of 2.6, a porosity of 0.4. and a bed thickness of 0.75 m. Normally, the Reynolds number for flow through a rapid sand filter media is less than 5. ii. Check that the conditions satisfy the low Reynolds number condition. iii. Determine the expected head if clean water is passed through the filter at the design flow.

A filtration system in a water treatment plant consists of four (4) filter boxes of the size = 45m^2 design flow= 40000 m^3/d, also obtained from Table 2.1. The filter bed is uniform with particles of size 0.50 mm, with specific gravity of 2.6, a porosity of 0.4. and a bed thickness of 0.75 m. Normally, the Reynolds number for flow through a rapid sand filter media is less than 5. ii. Check that the conditions satisfy the low Reynolds number condition. iii. Determine the expected head if clean water is passed through the filter at the design flow.

Fundamentals of Geotechnical Engineering (MindTap Course List)

5th Edition

ISBN:9781305635180

Author:Braja M. Das, Nagaratnam Sivakugan

Publisher:Braja M. Das, Nagaratnam Sivakugan

Chapter6: Hydraulic Conductivity

Section: Chapter Questions

Problem 6.8P

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Example 3: A non-uniform stratified sand filter described in Table below is to be backwashed at the velocity of 2.5×10-2 m/s. Determine the depth of the expanded bed for the sand filter using the following assumptions: The bed depth = 0.65 m Sieve Porosity = 0.45 No. Particle diameter, mm f, Mass fraction Drag coefficient = 0.4 - 1.5 0.02 Shape factor 0.85. 14 1.2 0.10 Density of water = 1000 kg/m³ Viscosity 1 x 10-3 N.sec/m² 20 0.8 0.18 SG of the filter particles = 2.6. 25 0.7 0.35 30 0.6 0.17 35 0.5 0.14 40 0.4 0.04
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