Standpipe Residual Case Study
  • Location: Spanaway, WA
  • Tank Size: 1,500,000 gallons 
  • Tank Type: Steel standpipe
  • Problem: Residual loss

Mixer improves water quality in 127 ft. standpipe

Spanaway, Washington

An operator at the Spanaway Water Company discovered significant thermal stratification after noticing condensation on the bottom, outside layer of a standpipe. Condensation was only visible 20 feet up the side of the 127 foot tank, where the cool and dense water coming into the tank had settled. Testing of the top layer of the tank revealed high water temperature and almost zero chlorine residual. Despite the challenging height of the standpipe, the PAX Water Mixer was able to penetrate each thermal layer and completely circulate the standpipe. After seven days, the entire tank was completely blended and overall water temperature was reduced. Grab samples showed a dramatic increase (from 0.00 mg/L to 0.31 mg/L) in chlorine residual at the top of the tank.

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