CLARIFIERS

1. CLARIFIERS Prepared By Michigan Department of Environmental Quality Operator Training and Certification Unit

2. CLARIFIERS Clarifiers Sedimentation Basins Settling Tanks Provide Quiescent Area Separation of Solids Settleable Floatable

3. Clarifiers Efficiency of Solids Removal Related To: 1. Characteristics of the Solids 2. Characteristics of the Water 3. Characteristics of the Clarifier

4. 2(p - po)g 9n (d/2)2 VF = Stoke’s Law VF = Fall Velocity (p - po)= Density difference between particle and water n = viscosity of water g = gravitational acceleration constant d = diameter of the particle

5. Stoke’s Law Forget the Formula Remember the Removal Efficiency Depends on Several Factors VF = Fall Velocity (p - po)= Density difference between particle and water n = viscosity of water g = gravitational acceleration constant d = diameter of the particle

6. Particle Size versus Settling Time Particle Size mm Order of Size Time to Settle

7. Clarifiers Efficiency of Solids Removal Related To: 1. Characteristics of the Solids 2. Characteristics of the Water 3. Characteristics of the Clarifier

8. VF = Fall Velocity (p - po)= Density difference between particle and water n = viscosity of water g = gravitational acceleration constant d = diameter of the particle Stoke’s Law Forget the Formula Remember the Removal Efficiency Depends on Several Factors

9. Settling Rate Cold Water More Dense More Viscous Warm Water Less Dense Less Viscous Solids Settle More Readily in Warm Water Than in Cold Water Warm Water - Greater Efficiency of Clarification Cool Water- Less Efficiency of Clarification

10. Clarifiers Efficiency of Solids Removal Related To: 1. Characteristics of the Solids 2. Characteristics of the Water 3. Characteristics of the Clarifier

11. Clarifiers Efficiency of Solids Removal Related To: 3. Characteristics of the Clarifier Surface Area Depth Hydraulic Loading Solids Loading

12. Clarifiers Efficiency of Solids Removal Related To: 3. Characteristics of the Clarifier Surface Area Depth Hydraulic Loading Solids Loading Design Operation Maintenance

13. Clarifiers Efficiency of Solids Removal Related To: 3. Characteristics of the Clarifier Flow Characteristics in the Clarifier Flow Must be Dispersed Evenly Throughout

14. Clarifier Short Circuiting Density Currents Higher Flow (Horizontal Velocity) in One Part of Tank Currents Within the Tank Carry Solids Through the Tank.  Not the Same as Excessive Hydraulic Load (Detention Time vs. Fall Velocity)

15. Clarifier Short Circuiting Causes Missing or poor influent baffling

16. Clarifier Short Circuiting Causes Missing or poor influent baffling

17. Clarifier Short Circuiting Causes Missing or poor influent baffling

18. Clarifier Short Circuiting Causes Uneven effluent weirs Plant growth or thrash in effluent weirs

19. Clarifier Short Circuiting Causes Temperature stratification between influent & clarifier water temperatures.

20. Clarifier Short Circuiting Monitoring for Short Circuiting Visual Observation Flow Over Weir Solids Over Weir

21. Clarifier Short Circuiting Monitoring for Short Circuiting Dye Testing

22. Clarifier Short Circuiting Density Currents Higher Flow (Horizontal Velocity) in One Part of Tank

23. Clarifier Short Circuiting Causes • Missing or poor influent baffling • Uneven effluent weirs • Plant growth or thrash in effluent weirs • Temperature stratification between influent & clarifier water temperatures.

24. Clarifiers Efficiency of Solids Removal Related To: 1. Characteristics of the Solids 2. Characteristics of the Water 3. Characteristics of the Clarifier

25. Clarifiers Types of Clarifiers Inclined Plate (Lamella) Rectangular Circular

26. Inclined Plate (Lamella)

27. Types of Clarifiers – Inclined Plate (Lamella) Discharge Flumes Distribution Orifice Feed Box Overflow Box Flocculation Tank Flash Mix Tank Coagulant Feed Clarifier Effluent Clarifier Influent Inclined Plates Sludge Discharge Sludge Hopper

28. Types of Clarifiers – Inclined Plate (Lamella)

29. Types of Clarifiers – Inclined Plate (Lamella) Increased settling efficiency due to increased surface area Smaller Area Needed for Installation

30. Types of Clarifiers – Inclined Plate (Lamella) Increased settling efficiency due to increased surface area Smaller Area Needed for Installation

31. Types of Clarifiers – Inclined Plate (Lamella) Seldom Used With Organic Wastes Biological Growths Reduce Efficiency Mostly Industrial Applications

32. Rectangular Clarifiers

33. Types of Clarifiers – Rectangular Effluent Weir Drive Unit Inlet Baffle Scum Trough Effluent Launder Flights Inlet Drive Gear Idler Sprockets Drive Chain Sludge Trough Sludge Withdrawal Pipe

34. Types of Clarifiers – Rectangular Inlet Baffle Inlet

35. Types of Clarifiers – Rectangular Influent baffling

36. Types of Clarifiers – Rectangular Settleable Floatable

37. Types of Clarifiers – Rectangular Effluent Weir Effluent Launder Effluent

38. Types of Clarifiers – Rectangular Settleable Floatable

39. Types of Clarifiers – Rectangular Solids Removal Mechanism Rails

40. Types of Clarifiers – Rectangular Drive Unit Drive Gear Idler Sprockets Drive Chain

41. Types of Clarifiers – Rectangular Flights

42. Types of Clarifiers – Rectangular Flights Rails

43. Types of Clarifiers – Rectangular Rails Wear Shoes

44. Types of Clarifiers – Rectangular Wear Shoes Rails Prevent Wear on the Flights Where They Contact the Rails Transfer Wear to the Shoe Instead of the Flights

45. Types of Clarifiers – Rectangular Flights Sludge Sludge Trough Sludge Withdrawal Pipe

46. Types of Clarifiers – Rectangular

47. Types of Clarifiers – Rectangular Scum Removal Scum Trough Flights Scum

48. Types of Clarifiers – Rectangular Scum Removal

49. Types of Clarifiers – Rectangular Scum Removal

50. Types of Clarifiers – Rectangular Effluent Weir Effluent Launder Effluent