An Uninvited Guest Shows Up at the Water Treatment Party

The water test showed no iron but iron was staining fixtures and walls. Denise and Michael discuss the reason and the fix for this problem.

Episode 7 Show Notes – An Uninvited Guest Shows Up at the Water Treatment Party

An activated carbon system was installed in a home in North Carolina.

• Application – PFOA/PFAS removal
• Water Source – Municipal Water
• Equipment supplied
  • 1054 tanks, lead / lag
  • Calgon Filtrasorb 400
  • Meter totalizer

A problem occurred after installation. The homeowner reported iron stains on shower walls and
commodes. Dealer reported the problem to Mike Urbans. Where was the iron coming from? Mike sent
the customer back to check for iron and pH, even though it was municipal water which should be
neutral 7.

• Test results on pretreated water: zero iron; 6 pH

Municipal water is not supposed to have a pH of 6. The pH of the water needs to be greater than 7 to
ensure that lead is not being introduced into the potable water.

The lower pH was causing iron to come off of the activated carbon. Coal based activated carbon has
minerals in it, including iron and low levels of arsenic. When it comes in contact with low pH water these
minerals are stripped out of the carbon. What the customer was seeing was the oxidized iron.

Solution

• Before installing equipment, test the well or municipal water prior to installation.
• To avoid having minerals like arsenic and iron come off, the carbon should be rinsed and
  backwashed before putting in service. Test again for iron.
• Acid rinsed and acid washed carbon are available at extra cost.
• If the pH is lower than 7, treat with a neutralizer or chemical feed system prior the carbon filter.

Municipal water supplies are generally very, very safe. In this case the homeowners have contacted the
municipality to advise and revise the situation.