1. 1 CEE 426 Wastewater Treatment Plant Design November 12, 2012 Thomas E. Jenkins President JenTech Inc. 6789 N. Elm Tree Road Milwaukee, WI 53217 414-352-5713 tom.jenkins.pe@gmail.com

2. 2 JCI 1 2 Water seeks its own level. My Dad

3. 3 JCI 1 3 Pumping Processes and Design Considerations  What is a Pump?  Types of Pumps  Pump Curves  System Curves  Pump System Performance

4. 4 JCI 1 4 What is a Pump?  A pump is a machine to move a fluid from a lower to a higher energy level  Pumps produce flow  System resistance to flow produces pressure

5. 5 JCI 1 5 Basic Physics: Continuity Equation: Always use consistent units 1 cu ft = 7.48 gallons

6. 6 JCI 1 6 Basic Physics: Pressure and “Head” Water = 62.4 lb/cu ft = 0.0361 lb/cu in One foot head = 0.433 psi One psi = 27.7 inches water

7. 7 JCI 1 7 Basic Physics: Bernoulli’s Equation (Energy Equation) In this case all pressures are expressed in feet of head. The application of Bernoulli’s Equation is used to construct the system energy grade line.

8. 8 JCI 1 8 Basic Physics: Theoretical Energy Required to Lift Water is Weight of Water Times the Height. Power is the Rate of Energy Used Over a Period of Time. To Pump a Certain Amount of Water Takes More Power If It Is Done Faster, But the Same Energy!

9. 9 JCI 1 9 Basic Physics: Actual Pump Power Must Include Efficiency. Power Cost Must Include Pump, Motor, And Drive Efficiency.

10. 10 JCI 1 10 Types of Pumps  Archimedes Screw  Positive Displacement  Centrifugal

11. 11 JCI 1 11 Archimedes Screw Pumps  Date from Ancient Greeks  Used for High Volume, Low Lift  Internal and External Types

12. 12 JCI 1 12 Positive Displacement (PD) Pumps  PD Pumps Move a Fixed Volume for Every Revolution  Many Types  Piston  Lobe  Gear  Progressive Cavity  Peristaltic  …..

13. 13 JCI 1 13 Positive Displacement Pump Examples Progressive Cavity Peristaltic Pump Usually Used for Slurries, Sludge, Heavy Fluids

14. 14 JCI 1 14 Positive Displacement Pumps Flow for a PD pump is linear with speed, but has a non- zero intercept due to “slip”. Slip is the internal leakage. This may also be expressed as volumetric efficiency. Discharge pressure will rise to meet system resistance (up to the point something breaks). PD pumps must always have pressure relief valves on the discharge.

15. 15 JCI 1 15 Centrifugal (Dynamic) Pumps  Centrifugal Pumps Convert Kinetic Energy Into Potential Energy (i.e. Velocity Head Into Static Head)  Most Common Pump in Water and Wastewater  Radial Flow Most Common  Axial Flow (Vertical Turbine) For High Flows

16. 16 JCI 1 16 Centrifugal Pumps  Many Types  Single and Double Suction  Horizontal and Vertical Split  Submersible  Close Coupled  Extended Shaft  …..

17. 17 JCI 1 17 Centrifugal Pumps Axial (Turbine) Pump Typical Centrifugal Pump Submersible Pump

18. 18 JCI 1 18 Centrifugal Pumps  Impeller Imparts Kinetic Energy To Water  Volute Slows Water, Converts Velocity Head to Static Pressure (Head)

19. 19 JCI 1 19 Centrifugal Pumps  Pump Capability Is Given In Manufacturer’s Performance Curve (Pump Curve)

20. 20 JCI 1 20 Centrifugal Pumps  Pump Performance Can Be Controlled By:  Trimming Impeller (Smaller Diameter)  Throttling Discharge  Variable Speed  Operating In Parallel  Same Pressure, More Flow  Operating In Series  Same Flow, More Pressure

21. 21 JCI 1 21 Centrifugal Pump Affinity Laws Variable Speed Pumps Are Used To Control Flow and Pressure. Variable Speed Operation Can Provide Significant Energy Savings. Most Effective If Pump Head Is Mostly Friction Losses. Variable Frequency Drives (VFD) Are the Most Common Method for Variable Speed Control.

22. 22 JCI 1 22 Centrifugal Pump Affinity Laws

23. 23 JCI 1 23 Centrifugal Pump Performance  Pump Operation Cannot Be Determined From Pump Curve Alone  Must Include System Curve  Operating Point Is Identified By the Intersection of the Pump Curve and System Curve

24. 24 JCI 1 24 Centrifugal Pump Performance The pump head is the sum of the static head (lift) and the friction losses. The friction loss can be determined from the Darcy-Weisbach equation or the Hazen- Williams equation. The Hazen-Williams is the most often used in water and wastewater.

25. 25 JCI 1 25 Centrifugal Pump Performance  Adding System Curve Identifies Actual Pump Performance

26. 26 JCI 1 26 http://www.pumpsystemsmatter.org/default.aspx http://www.pumps.org/ Questions?