Water Treatment (CEng 5403) Assignment For Sedimentation The diameter of particles is 0

Water Treatment (CEng 5403)

Assignment For Sedimentation

1. The diameter of particles is 0.1 mm of specific gravity 2.5. Find the settling velocity of the particles at 10^oC. The kinematic viscosity of water at 10^oC is 31 centistokes. And find the maximum surface loading rate for removing 0.1 mm particles. (at T=10^oC, ρ=999 kg/m³)

2. Estimate the terminal settling  velocity in water at a temperature of 15^oC of spherical silicon particles with specific gravity 40 and average diameter of (a) 0.05 mm and (b) 1.0 mm (at T=10^oC, ρ=999 kg/m³ and μ=0.00113 N s/m²)

3. Write a computer program which will calculate the terminal settling velocity given the diameter, SG, temperature, ρ and μ.

4. Based on the settling column analysis of discrete particles the following data was obtained. The samples collected at 120 cm depth of column.

Calculate the % removal of discrete particles of loading rate of 40 m³/d/m²

5. The following test data were gathered to design a settling tank. The initial suspended solids concentration for the test was 20.0 mg/L. determine the detention time and overflow rate that will yield 60 % removal of suspended solids. The data given are suspended solids concentrations in mg/L.

0.5            6.2       5.0

1.0          15.0     13.0     10.6     8.2       7.0    6.0

1.5          15.4     14.2     12.0     10.0     7.8    7.0

2.0          16.0     14.6     12.6     11.0     9.0    8.0

2.5          17.0     15.0     13.0     11.4     10.0    8.8

            *Depths from top of column, column depth = 2.5 m

6. A water treatment plant has four clarifiers treating 4.0 mgd (0.175 m³/s) of water. Each clarifier is 4.88 m wide, 24.4 m long, and 4.57 m deep. Determine: (a) the detention time, (b) overflow rate, (c) horizontal velocity, and (d) weir loading rate assuming the weir length is 2.5 times the basin width.

7. A clarifier with an area of 150 m² treats a flow of 3000 m³/d. The water entering the clarifier contains a substantial number of clay agglomerates with a specific gravity of 1.05 and a diameter of 0.05 mm. What percentage of these particles will be removed in the clarifier?

8. A flow of 1 m L/d has to be treated in a sedimentation tank with an overflow rater of <50 m³/d/m². Design a rectangular tank of detention period of 2h and depth of tank is 3 m. L:B is 3:1. If the water contains 600 mg/L of suspended solids and 33% are settleable. Calculate the volume of sludge storage for 30 days cleaning period.

   AAiT

   Department of Civil Engineering

   Water Treatment

9. The following test data were gathered to design a settling tank. The initial turbidity for the test was 33.0 NTU. Determine the detention time and overflow rate that will yield 88% removal of suspended solids. The data given are suspended solids concentrations in NTU.

             ^a Depths from top of column, column depth = 4.0 m.

10. Design a horizontal flow rectangular sedimentation basin using high-rate settlers for a maximum day design flow rate of 25,000 m³/d. Assume a water temperature of 12^oC, that the angle of the settler tubes is 60^o, and that they have a hydraulic diameter of 0.05 m. Also assume the floc has excellent settling characteristics. Provide the following in your summary of the design:

Q design

Number of tanks

Width of each tank

Length of settler

Length of each tank

Side water depth Depth of sludge zone v approach

v_fc: velocity in the settler

Reynolds number

Froude number

Number of launders

Launder length

Weir loading

Type of sludge collector