One way to think about engineering is to consider it the organized study (and avoidance) of failure Here are 25 different failures (plus a few bonuses) to avoid on your next lift station project, whether it's a clean-sheet design, a retrofit, or a rehabilitation. Avoiding these mistakes will improve safety, performance, and maintenance-friendliness.

1. 25 Ways to Screw Up a Lift Station Design
Brian Gongol
DJ Gongol & Associates, Inc.
March 31, 2021
Iowa WEA Region V Spring Meeting
Huxley, 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

Flow and inlet diameter determine
inlet velocity

Velocity determines
required submergence

If you can't add more depth,
widen the inlet

Velocity (in fps) =
GPM x 0.41 / (diameter2
)

Refer to published submergence
charts

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. Which is the better VFD candidate?

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

25. 8. Overlooking a soft starter

26. Sometimes motors just need a gentle nudge

27. 9. Turning piping into a spaghetti bowl

28. Simplify until you can't anymore

29. 10. Under-sizing the wetwell

30. Bigger wetwells are a gold mine

Guarantees future capacity

Adds safety factor to your emergency-response time

Insures against backups and basement flooding

Facilitates better equipment spacing

Reduces frequency of motor starts

Note: If slow turnover is a concern, septic issues can be
addressed with small mixing and/or aeration systems

31. 11. Not accounting for maintenance

32. Stations need tools, space, and trained people

33. What have we learned from the pandemic?
"Social distancing" requires us to demand
safe, roomy working conditions

34. 12. Omitting valves for air and vacuum

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

36. Remember: Your pipes are like you
If your pipes can't breathe,
they might collapse

37. 13. Failing to provide adequate heat

38. Below ground or above, stations need heat

39. 14. Failing to provide adequate cooling

40. Motors, controls, and people need cooling

41. 15. Omitting gauges

42. Nothing is a better for seeing deep inside

43. Don't go without gauges
A pump system without gauges
is like a doctor without a stethoscope

44. 16. Cutting solids passage too small

45. Residents aren't becoming more careful

46. Stringy solids + FOG = Headaches

47. 17. Skipping NPSH calculations

48. Always calculate NPSH, even for submersibles

49. NPSH is the root cause of many problems
Those problems do not go away
just because the pump is hidden underwater

50. 18. Not planning for clogs

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

52. Want to see it?

53. Even if you got rid of wipes...
Clogging issues are only going to get worse
as household and commercial users
behave more efficiently

54. Dishwashers, clothes washers, showerheads...

55. 19. Misaligning equipment to staff capacity

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

57. You need to be able to fix things yourself
You can't predict when:

Mar 2021 | A ship will get stuck and block the Suez Canal

Feb 2021 | A freak winter storm will shut down Texas

Aug 2020 | Rolling blackouts will close California

June 2020 | China will run out of shipping containers

Mar 2020 | States will mandate two-week quarantines
on interstate travel

58. 20. Under-sizing motors

59. Size the motor for the far-right

60. 21. Failing to calculate future head curves

61. Your system will change, so be ready

62. 22. Fixating on limited backup options

63. Consider all the choices

64. Backup power isn't a stand-alone luxury
You need backup power when
something else is already going wrong

65. 23. Cutting corners on material quality

66. Aim for long-term maintenance

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

68. 24. Designing a second-class workspace

69. Clean, safe workplaces matter

70. 25. Going underground without need

71. Put nothing underground that could go above

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

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

74. 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

75. 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/

Photo of blimp over the Lincoln Memorial is in the public domain

http://www.loc.gov/pictures/item/2016889614/

Reflected wave phenomenon article screenshot from Eaton:

http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/
thereflectivewavephenomena.pdf

NPSH formula taken from "Selection and Application of Self-Priming Centrifugal Pumps",
courtesy of the Gorman-Rupp Company

Dishwasher manual screenshot is from the Kitchen Aid KDTE254ESS1

Pump curve courtesy of the Gorman-Rupp Company

Image showing three lift station types courtesy of the Gorman-Rupp Company

All other photos and illustrations are the original work of Brian Gongol and all rights are
reserved