Maintenance is often a necessary evil -- most people don't like doing it, but the less it's done, the worse the consequences. Here are some observations about ten of the most common hassles encountered in wastewater pumping applications and how to avoid (or at least reduce) them.

1. TOP 10 HASSLES IN WASTEWATER PUMPING
Brian Gongol
DJ Gongol & Associates, Inc.
October 7, 2016
Iowa WEA Region IV Meeting
Atlantic, Iowa

2. Ten common problems in no particular order
Your troubles will vary

3. Problem #1: Clogging

4. There's no such thing as "non-clog"
Shall we go looking for unicorns, too?

5. Is this real life? Or is this just fantasy?
Anyone who insists that
a pump is "non-clog"
clearly hasn't seen the kinds of things
real people dump down the drain

6. ANY pump can clog. Period.

7. What matters
 Resistance to clogging
 How quickly the pump can
be unclogged
 How quickly the pump can
return to service

8. Trash baskets
 People don't use them because they clog
 ...but then the pumps clog

9. VFDs are not a magic pill
They can be helpful in some cases,
but they risk running too slowly

10. Low pump speeds can reduce inlet velocities
And slow inlet velocities can lead to clogging

11. Use caution with shredders and grinders

12. Solids passage beats solids decimation
It is often better to
pass a large solid intact
than in many small bits

13. Pass the whole baseball...

14. ...or all of the string and bits inside it?

15. Small solids plus high FOG
A recipe for disgusting trouble

16. Solids with neutral buoyancy
May be invisible from surface inspection
but still cause clogs

17. You can't prevent every clog
(Not as long as idiots can still flush mop heads)

18. Half-filled basketballs

19. Waterlogged wood

20. Drywall, insulation, and sheets of liner material

21. Storms will always bombard wetwells

22. Backflushing/jetting doesn't always solve it
If the debris is still there,
the problem is too

23. Clogged piping may require cutters

24. Wetwells may require vacuum trucks

25. New pumps may clog when old ones didn't
For instance:
Better suction pulls settled material from the wetwell

26. Prevent clogs
 Make sure you have true 3" clearances
 Keep the wetwell clear
 Run pumps at appropriate speeds

27. But when clogs happen...

28. Ask: How quickly can you return to service?

29. How much does downtime really cost?

30. Total cost of a clog
 Cost of pump downtime
 Cost of extraction
 Cost of labor (service charges or your own time)
 Cost of transit
 Cost of unclogging
 Cost of parts
 Cost of bypass pumping if required
 Cost of sewer backup risk
 Cost of reinstallation

31. And one very important cost
The opportunity cost of your time

32. Opportunity cost
 You might be a pump specialist
 You might be a jack of all trades
 Either way...

33. You have to place a value on your time

34. Opportunity cost
The cost of doing one thing
when you could be doing
something else

35. Real total costs
Real total cost =
out-of-pocket cost
+ labor cost
+ opportunity cost

36. Don't overlook other potential clogging sites
 Lines to air release
valves
 Drain lines
 Cooling jackets
 Gauge taps

37. Little clogs, big headaches
 Rubber center of a golf ball
 Springs

38. Problem #2: Cavitation

39. Cavitation can occur on suction or discharge

40. Any centrifugal pump is at risk
 Submersible
 Flooded-suction
 Suction-lift

41. Cavitation cause #1
Errors in system design

42. Cavitation cause #2
Pump clearances open up over time due to wear

43. Cavitation cause #3: Valve changes
Even when
seemingly
innocuous

44. Cavitation cause #4
Broken,
damaged or
closed ARVs on
a forcemain

45. Cavitation cause #5
Force main constriction due to
sedimentation, air pockets,
or other changes in condition

46. Cavitation cause #6: Broken mains and valves

47. Listen closely: Suction cavitation

48. Listen closely: Discharge cavitation

49. Document performance with all of your senses
Documentation is the only way
to report the full story

50. Or maybe all but one.

51. We too often use sight as a crutch
Sounds, smells, vibrations, and temperatures all matter

52. If you're at risk for cavitation
 Hardened parts can reduce wear
 Hardening delays the pump from falling out of tolerance

53. Ask this
How easily can the
tolerances and clearances
be maintained?

54. Identifying cavitation by autopsy
Discharge-side cavitation

55. Identifying cavitation by autopsy
Suction-side cavitation

56. Uniform abrasive wear isn't cavitation

57. Problem #3: Animals, vermin, and nature being a jerk

58. Warm, protected spaces are attractive

59. Seal your gaps with gaskets

60. Keep doors closed

61. Patch holes

62. Keep things off the floor

63. Containerize with plastic

64. Containerize with plastic
Avoid wood, cardboard, and metal

65. Sweep and clean up

66. A place for everything; everything in its place

67. Natural enemy: Muskrats
 Swim into warm wetwells
 Get sucked up into pipes and pumps (they're squishy)

68. Natural enemy: Turtles
 Swim into warm wetwells

69. Natural enemy: Turtles
 Block off suction inlets

70. Natural enemy: Turtles
 Cause pumps to overheat and shut down

71. Natural enemy: Turtles
 Swim away once the lag pump lowers the wetwell to
the off-elevation

72. Natural enemy: Turtles
 The operator gets the call, runs out to the station and
can't find anything wrong

73. Natural enemy: Rattlesnakes
Especially in Southern and Eastern Iowa

74. Natural enemy: Bees, wasps, and hornets

75. Natural enemy: Spiders

76. Ask: Can we really keep the pump station clean?
Showroom clean may be too ambitious,
but do aim for functionally clean

77. Problem #4: Lubrication

78. Seals
 Oil-lubricated
 Grease-lubricated
 Water-lubricated
 Lubrication by media

79. Bearings
Oil or grease

80. Maintenance charts

81. Treat it like a bowling scorecard

82. Clean up spills

83. Use simple checklists

84. Rule of 7

85. Rule of 7

86. Problem #5: Seal failures

87. Cause: Debris like sand and grit

88. Cause: Alignment problems

89. Cause: Mechanical vibration

90. Cause: Hydraulic imbalance

91. Ask: Can I replace my own seals?

92. Keep pump stations clean

93. You can only see what's wrong if you know what looks right

94. Problem #6: Motor failure

95. Power surges and lightning strikes

96. Excessive starts per hour

97. Mice building nests in motors

98. Car accidents can cause pump problems

99. Car accidents can cause pump problems
 Power line comes down
 Power company makes repairs
 Phases get reversed
 Pump runs backwards

100. VFDs at a distance
VFDs more than 100' from the motor
can cause reflected waves

101. Use infrared temperature sensors to track

102. Know the motor's lubrication requirements

103. Ask: Are replacement motors readily available?

104. Ask: Are the sensors useful?
For submersibles:
Do moisture sensors give you time to react?
For ODP/TEFC:
Is it worth doubling or tripling the cost
of an off-the-shelf motor?

105. Problem #7: Temperature problems

106. Overheating...and freezing

107. Proper ventilation for summer and winter

108. Heaters are cheap

109. Frozen water-line epidemic of 2014
Don't waste a good, widely-experienced crisis!
People forget pain very, very quickly

110. Ask: Are we using the right enclosures?

111. Problem #8: System changes

112. System head curves change over time

113. Wear can cause pump performance to change

114. Sedimentation adds to friction losses

115. Water hammer can break valves and pipes

116. Ask: Is the system protected against surges?

117. Air buildup where ARVs should be installed

118. ARVs can fail, raising discharge heads

119. Ask: Do we have ARVs and surge valves?

120. Document performance on a pump curve

121. Problem #9: Vortexing and air entrainment

122. All centrifugal pumps are susceptible

123. Pumps are meant to move water
If you need to move air, get a fan

124. Air leads to irregular shaft loads

125. Inlet main failures
Can explain surprise low-water alarms

126. Fix air entrainment with baffles

127. Fix vortexing with proper pump spacing

128. Fix vortexing with added submergence

129. Problem #10: Inattention to safety

130. Safety isn't the problem - complacency is

131. Safety mentality always starts at the top

132. Nobody will watch out for your safety like you

133. You are not paid enough to risk life and limb

134. Ask: Is there a safer way?

135. A path to fewer hassles

136. It starts with recordkeeping

137. You're probably a hands-on person

138. You need the help of numbers people

139. Appeal to their way of thinking, not your own

140. Your inconveniences mean little to them

141. Learn to quantify your troubles
Make pumping hassles a matter of dollars and cents

142. Take gauge readings and record them

143. Document spills and leaks...look for patterns

144. Record smells, sounds, temperatures

145. Get comfortable with spreadsheets

146. Officials and managers need hard evidence

147. Engineers need actionable observations

148. Equipment suppliers need feedback

149. Spare parts
Availability of replacement pumps, motors, and parts
is essential to maintenance

150. Spare parts
Your shelf
+ local supplier's shelf
+ manufacturer's shelf

151. Don't put off maintenance and improvements
Deferred maintenance costs
aren't any less real
just because we defer them

152. Compounding interest can make you rich

153. Deferred maintenance costs compound, too

154. Compounding costs can ruin a great system
 Decide what you need
 Measure the total costs
 Document
 Quantify, quantify, quantify
 Make the case to get what you need to serve the public

155. Questions?
 Thank you for coming!
 Brian Gongol | DJ Gongol & Associates
 515-223-4144 | info@djgongol.com | @djgongol

156. References
 All images are original work by and copyright reserved
to Brian Gongol
 Pump curves used courtesy of the Gorman-Rupp
Company