CS 5 – Water Conservation in Paint Sludge System


  • Galaxy noticed that the conductivity of a 150,000 gallon sludge pit was not cycling up as it normally should
  • It was suspected the water was being dumped to waste water treatment somehow and the plant was likely losing a lot of water


  • Galaxy was treating an automotive assembly plant paint sludge system
  • Galaxy began to look for ways that the booth water could be getting out of the system because the water chemistry was not cycling up
  • The process was studied and it was found that water was being added to the sludge system when the booth went into entry mode – the reduced air volume allowed water to fill the booth impact pond
  • This dropped the water level in the sludge pit, causing the auto water fill to add fresh water
  • When the booth came out of entry mode, the increased air velocity blew the excess water out of the impact pond
  • This caused the sludge pit level to increase and activated the automatic blow down to waste water


  • The PLC was programed to disable the make-up water to the sludge system while the booth was in auto mode


  • The automaker verified that over 15.5 million gallons of fresh water was saved on an annual basis
  • The annual flow to the waste treatment plant was reduced by the above amount

CS 5 – Water Conservation in Paint Sludge System