1. Sedimentation & filtration
Present by : Ngoc Tran
Shamia salih
Hong Nguyen

2. Sedimentation
Sedimentation is the natural process in which particles is carried to the bottom of a body of water and forms a solid layer

3. Sedimentation

4. Purpose To measure the diameter of the particles
At fixed time intervals samples were taken from the suspension at different depth

5. Industrial use
Water treatment
Food industry
In geology
Blood test

6. Hydrometer
Hydrometer is used to determine the specific gravity or relative density of liquids
It is normally made of glass and it is usually weighted with mercury or lead shot to make it flow upright.

7. Hydrometer
The operation of hydrometer is based on Archimedes’ principle
The lower the density of the substances, the further the hydrometer will sink

8. Hydrometer
There are different types of hydrometer used based on the density of the liquid
variety of scales of hydrometer used depending on what you want to measure

9. A Type of Hydrometer

10. Procedure
Measure a white solid powered (20g)

11. Procedure
Fill a 1000ml cylinder with 900ml of water

12. Procedure
Pour the white powder into the cylinder and shake it until the water and the powder are evenly distributed

13. Procedure
Then place the hydrometer into the cylinder

14. Procedure Measure the temperature Then set the timer
Measure the height of the hydrometer at 0 seconds
And then start recording the height in time intervals until the height is constant

16. Motion of sphere particle

17. MOTION OF SPHERE PARTICLE
If the particles are sphere of diameter Dp
At low Reynolds numbers the drag coefficient varies inversely with Re of particle
Re=G*D/µ)

18. calculation diameter of the particle
To calculate values of effective depth from the equation: L = L (L2 -VB /A) or table 2
L1 : distance along the stem of the hydrometer from the top of the bulb to the mark for a hydrometer reading.
L2 : overall length of the hydrometer bulb (L2 = 14.0 cm)
V B :volume of hydrometer bulb (V B = 67.0 cm3)
A = cross-sectional area of sedimentation cylinder (A = 27.8 cm2)
To find the value correction factor α from table 1
To find K value from table 3

19. SG=2.53  α=1.024

20. Reading L1=10  L=14.7

21. At 220C & SG=2.53  K=

22. CALCULATION & ANALYSIS
T (min)
Actual reading
Effective L
D (mm)
% P 20
13.04 1 18
13.37
0.05
69.63 2 17
13.53
0.04
64.51 3 15
13.86
0.03
54.27 4 14
14.02
49.15 5 12
14.34
0.02
38.91 6 11
14.51
33.79 7 10
14.67
28.67 8 9
14.83
23.55
15.00
18.43
15.16
13.31
15.32
8.19
Temperature : C
Volume (ml) ml
Dry mass (gram) g
Concentration: %
SG : g/cm3
K (Table 3)
a (Correction Factor Gs)
b (Correction Factor Temp) 4.4

24. THEORY OF FILTRATION
Filtration is a very important step in the entire process of solid-liquid separation which can be sub-divided into four major stages
(1) Pretreatment
(2) Solids concentration
(3) Solids separation
(4) Post-treatment

25. Types of filtration Basically, there are two types of filtration
(1) Depth filters - used for deep bed filtration where particle deposition takes place inside the medium and cake deposition on the surface is undesirable.
(2) Surface filters – Used for cake filtration where the solids are deposited in the form of a cake on the up-stream side of a relatively thin filter medium.

26. Rotary Filtration
Purpose: To separate water and solid

27. A pre-coat is a layer of fine particular material added on to the filter septum before filtration to form a coating cake

28. Rotary vacuum filter drum + consist of a drum rotating in a tub of liquid to be filtered. + pre –coat +vacuum sucks liquid and solids onto the drum pre- coat surface . + the solids adhere to the outside of the drum + knife cut the solid out of drum . The knife advances automatically as the surface is removed.

29. The pump
Vacuum filtration usually involves the use of a vacuum filter flask, a filter trap, a water pump
the liquid is sucked down into the filter flask by the action of the water pump, and any excess liquid that overflows out of the filter flask is caught in the filter trap

30. Procedure Fill the tank with the mixture
Turn on the valve for water go to the pump
Turn off all the valves which are drain out the water from the tank, pump, and drum.
Turn on the main switch and all the buttons.

31. Continue Vacuum pump Agitator drive Filter drive Pre-coat drive
Filtrate pump

32. Valve for water come to the pump
Valves drain out all water after finish
Drain valve
(blue)valve for water drain out the tank after finish
(green )valve control the water go to the pump

33. The filter-cake resistance
specific resistance the local porosity and permeability (or specific resistance), as well as the constitutive relations for the drag force between the phases and the solid matrix stress are required to obtain the numerical solution of the equations.
The medium resistance is a function of the medium itself and the material being filtered.
Resistance arises from the filter cloth, mesh, or bed, and to this is added the resistance of the filter cake as it accumulates.
The filter-cake resistance is obtained by multiplying the specific resistance of the filter cake, that is its resistance per unit thickness, by the thickness of the cake. R = µr(Lc + L)

34. the properties of a filter cake
The key properties of a filter cake are the cake porosity and permeability
The cake porosity (ε ) is a measure of the fluid capacity of the formed cake or the fraction of a porous medium available for fluid flow.
The cake permeability ( k ) is an indication of how easily the fluid can pass through its voids under an applied pressure gradient.
The extent of permeability is determined by the porosity of the medium and also the sizes of pores in its internal structure.

35. Rotary filtration Batch filtration
Dry cake
Wet cake
θ: Angle comprising the sector immersed in the suspension
Batch filtration

36. mass balance for the solid in the cake
Solids accumulate in cake = Solids removed from suspension. LAԐ the volume of water in the cake
The volume of water contained in the LAԐ is much smaller than VF1 the volume of filtrate.

37. Pressure Drop During Cake Filtration

39. Rotary Vacuum Filtration
Fraction Submergence of drum surface θ/2π : fk
Time cycle 2π/ω : tc
The time immersion period in each cycle : t= tc * fk
Rotation velocity ω (rad/s)
θ: Angle comprising the sector immersed in the suspension
Filtration Flux
If the Rm is very small
Amount of solid

40. CONCLUSION The diameter of the particle
The concentration of the particles
The cake permeability ( k ) is an indication of how easily the fluid can pass through its voids under an applied pressure gradient
The cake porosity (ε ) is a measure of the fluid capacity of the formed cake or the fraction of a porous medium available for fluid flow Pressure drop
Total pressure drop: P drop cross filter & P drop due to filter medium
Specific cake resident: the local porosity and permeability
The speed of the drum rotation ω
The filtrate flow rate
The amount of solid

41. References Unit Operations textbook Dr. Lo Dr. Jang Mr. Minh Tran
Friend: Cody

42. QUESTIONS