Through the careful study (and avoidance) of failure, engineering can make use of the past to improve on the future. Pump station design is no exception. Join this speedy trip through 25 entirely avoidable screwups to see how things can go wrong -- and learn how to make sure they go right next time.

1. 25 Ways to Screw Up
a Lift Station Design
Brian Gongol, M.Ed.
DJ Gongol & Associates, Inc.
June 7, 2023
Iowa Water Environment Association Annual Conference
Waterloo, Iowa

2. Rule #1 of lift station design:
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
Vice-Chairman
Berkshire Hathaway
2

3. 1. Omitting toxic-gas detection

4. The risks grow bigger as you go deeper
• Carbon monoxide
• Methane
• Hydrogen sulfide

5. Low-cost gas monitors can be lifesavers

6. 2. Cramping pumps, valves, and people

7. If nobody can work on it,
don’t expect it to work

8. Leave room
for people,
tools, and
parts

9. 3. Permitting air entrainment in the wetwell

10. A pump is not a
fan, but air will
try to weasel in

11. Use baffles and wetwell diameter effectively

12. 4. Overlooking the curse of vortexing

13. A vortex looks magical, but it’s a demon

14. Set low-water levels well 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 required
6" - 2.278 fps, 1.5' submergence required

15. 5. Allowing inlets to cascade onto pumps

16. Locate pumps
carefully and
plan for
waterfalls

17. 6. Locating a
VFD too far
from the motor

18. Sine waves can bounce back and interfere

19. Those reflected waves can mess up motors

20. 7. Using a VFD where
static head prevails

21. One of these is a much better VFD candidate

22. If a component doesn’t add value, cut it out

23. 8. Overlooking end-of-line
power concerns

24. Lift stations often go on the edge of town

25. Soft starters can help keep the lights on

26. 9. Turning piping into a spaghetti bowl

27. Excess piping complexity leaves time bombs

28. Simplify
until you
can’t
simplify
anymore

29. 10. Under-sizing the wetwell

30. A big wetwell is 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, & trained people

33. What has the pandemic taught us?
• Be able to do it yourself: You can’t count on bringing in outside help
• Hobbled supply chains make regular maintenance critical
• "Social distancing" requires us to demand good working conditions
• Meaning: Safe, well-ventilated, and roomy

34. 12. Neglecting the role of air

35. Air valves at high points and on long runs

36. Pipes are just like you
If your pipes can’t breathe
(both in and out),
they might collapse

37. 13. Leaving out the heat

38. Heat now or pay to replace equipment later

39. 14. Failing to provide adequate cooling

40. Motors, controls, and people need cooling

41. By the way, that goes for starts per hour, too
Motors are like horses:
Give them a good run,
then give them time to cool down

42. 15. Omitting gauges

43. Nothing is better for
seeing deep inside

44. Gauges are vital to expert troubleshooting
A pump system without gauges
is like a doctor without a stethoscope

45. 16. Cutting solids passage too small

46. The public is
not becoming
more careful

47. Stringy solids + FOG = Headaches

48. 17. Skipping NPSH calculations
48

49. Always calculate NPSH
(even on submersibles and flooded suctions)

50. NPSH: The root cause of many problems
Those problems do not go away
just because a pump is hidden
underwater

51. 18. Failing to plan for clogs

52. Even if you got rid of “flushable” wipes…
Clogging issues are only going to
get worse as household and
commercial users behave more
water-efficiently

53. New appliances have slashed water waste

54. Always know your exit strategy (for clogs)
54

55. 19. Misaligning equipment to staff capacity

56. You break it, you bought it.
But can you fix it?

57. Why “fix it yourself” is imperative
• You can't predict when:
• Apr 2022 | China will lock down entire cities like Shanghai
• 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 put two-week quarantines on interstate travel

58. 20. Under-sizing motors

59. Size motors to the far-right side of the curve

60. 21. Failing to calculate future system heads

61. Your system will change, so be ready

62. 22. Fixating on one backup-power option

63. Consider all of the available choices

64. Backup power isn’t a stand-alone luxury
Q. When do you need backup power?
A. When something else is already going wrong.

65. 23. Cutting corners to spend less up-front

66. Aim for life-cycle
efficiency, not
just “cheap”

67. Amortize equipment durability into capex
Lots of factors count:
• Hardness
• Ductility
• Tensile strength
• Corrosion resistance
• Machinability
• Availability

68. 24. Settling for second-class workspaces

69. Cleaner facilities are safer facilities

70. Water professionals deserve
professional-quality work spaces

71. 25. Going underground without need

72. Put nothing underground if it could go above

73. Bonus round: Other errors not to make
• 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

74. Remember:
Engineering is the study (and avoidance) of failure,
so pay attention to the mistakes around you.
And then, don’t make them again.

75. Questions?
• Thank you for your attention
• Don’t hesitate to follow up with
questions anytime (at no
obligation)
• This presentation is available at
gongol.net/presentations
• Brian Gongol
DJ Gongol & Associates, Inc.
West Des Moines, Iowa
• brian@djgongol.com
• 515-223-4144
• @djgongol on LinkedIn, Twitter,
and Facebook

76. 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.p
df
• 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