Bacteria in
Purified Water

    Bacteria able to form Colony Forming Units

    These living microorganisms are capable of growing in ultra-pure water. Bacteria are a common cause of problems associated with high purity water systems. Regular testing enables the detection of rising levels before they are able to cause product loss. The most influential criteria for the presence of bacteria, in a water system, are low flow rates.

    Epifluorescent (TOTAL)
Bacteria Cell Counts

    This method yields results in terms of total (living and dead) bacterial cells present in 100ml of sample. Epifluorescent bacteria counts are most often used in conjunction with viable counts. Rising total cell counts are a good indication of slime becoming dislodged, or other issues that put an increased load on the water purification system.

    LAL (Limulus Amoebocyte Lysate) or Pyrogen Test for Endotoxin levels

    This “endotoxin” assay quantifies the gelatinous, polysaccharide matrix that surrounds gram negative bacteria (most bacteria in the ultrapure water system). Since there is no average amount of polysaccharide associated with a cell, the test results are given as nanograms per milliliter of water.

    Contaminant Problem Cause Possible Cure
    Bacteria High port counts Dead Leg
    Bad port
    Shorten leg,
    Increase flush time until ok
    Replace port
    High at pt.of use low flow
    dead legs
    Bigger pump
    Reduce back pressure
    High tank counts tank too large Smaller tank
    Higher flow rates
    Nitrogen blanket
    Ozone layer