25 key elements to make sure you get right in your next lift station design

1. 25 Ways to Screw Up a Lift Station Design
Brian Gongol
DJ Gongol & Associates, Inc.
August 28, 2019
Iowa AWWA Fall Short Course
Ankeny, Iowa

2. Don't make the same mistakes twice
We're very good at ignorance-removal,
and fortunately for us,
we have a lot more ignorance to remove."
- Charlie Munger

3. 1. Omitting toxic-gas detection

4. The risks get bigger as you go deeper

5. Low-cost gas monitors can be lifesavers

6. 2. Cramping pumps, valves, and people

7. It won't work if nobody can work on it

8. The ideal: Room for people, tools, and parts

9. 3. Permitting wetwell air entrainment

10. A pump is not a fan, but air will butt in first

11. See it happen

12. Use baffles and diameter effectively

13. 4. Vortexing

14. A magical sight, but not helpful

15. Want to see it happen?

16. Set low water levels safely above pump inlets
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Flow and inlet diameter determine
inlet velocity
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Velocity determines required
submergence
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If you can't get more depth, widen
the inlet
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Velocity (in fps) =
GPM x 0.41 / (diameter2)
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Refer to published submergence
charts
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At 200 gpm:
4" - 5.125 fps, 3.0' submergence
6" - 2.278 fps, 1.5' submergence

17. 5. Cascading inlets onto the pumps

18. Locate pumps carefully or use pipes, baffles

19. 6. Locating a VFD 75' or more from the motor

20. Bouncing back

21. Reflected waves can mess up a motor

22. 7. Using a VFD where static head prevails

23. If it doesn't add value, take it out

24. 8. Overlooking a soft starter

25. Sometimes motors just need a gentle nudge

26. 9. Turning piping into a spaghetti bowl

27. Simplify until you can't anymore

28. 10. Under-sizing the wetwell

29. Bigger wetwells are a gold mine
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Future capacity

Adds time to respond in an emergency
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Septic issues can be addressed

30. 11. Not accounting for maintenance

31. Stations need tools, space, and trained people

32. 12. Omitting valves for air and vacuum

33. High points, local high points, and long runs

34. 13. Failing to provide adequate heat

35. Below ground or above, stations need heat

36. 14. Failing to provide adequate cooling

37. Motors, controls, and people need cooling

38. 15. Omitting gauges

39. Nothing is a better for seeing deep inside

40. 16. Cutting solids passage too small

41. Residents aren't becoming more careful

42. Stringy solids + FOG = Headaches

43. 17. Skipping NPSH calculations

44. Always calculate NPSH, even for submersibles

45. 18. Not planning for clogs

46. This too, must pass: Even a rubber chicken

47. Want to see it?

48. 19. Misaligning equipment to staff capacity

49. If you break it, you ought to be able to fix it

50. 20. Under-sizing motors

51. Size the motor for the far-right

52. 21. Failing to calculate future head curves

53. Your system will change, so be ready

54. 22. Fixating on limited backup options

55. Consider all the choices

56. 23. Cutting corners on material quality

57. Aim for long-term maintenance

58. Amortize costs of better equipment into capex
Lots of factors count:
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Hardness
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Ductility
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Tensile strength
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Corrosion resistance

59. 24. Designing a second-class workspace

60. Clean, safe workplaces matter

61. 25. Going underground without need

62. Put nothing underground that could go above

63. Bonus Round
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Not conducting a surge analysis
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Failing to plan for grit and solids buildup
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Choosing the wrong voltage
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Putting safety second
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Skipping a system test
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Failing to account for water volumes in sewer lines
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Failing to account for water volumes in force mains

64. Above all...
Engineering is the study (and avoidance) of failure...
so pay attention to the mistakes around you.
And then don't make them.

65. Questions?

Thank you for your
attention

Do not hesitate to follow
up with questions
anytime (no obligation!)

Brian Gongol
DJ Gongol & Associates

515-223-4144

info@gongol.net

@djgongol on Twitter,
Facebook, and Instagram

66. Sources and References

Photo of Dwight Eisenhower in uniform from US Army collection is in the public domain

http://www.loc.gov/pictures/item/2009634158/
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Photo of blimp over the Lincoln Memorial is in the public domain

http://www.loc.gov/pictures/item/2016889614/
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Reflected wave phenomenon article screenshot from Eaton:
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http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/
thereflectivewavephenomena.pdf
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NPSH formula taken from "Selection and Application of Self-Priming Centrifugal Pumps",
courtesy of the Gorman-Rupp Company
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Pump curve courtesy of the Gorman-Rupp Company
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Image showing three lift station types courtesy of the Gorman-Rupp Company
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All other photos and illustrations are the original work of Brian Gongol and all rights are
reserved