Pre-treatment of process water

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In a MD cleaning process, avoiding bacterial growth, especially in demineralised water rinses, is a challenge. Water flows through sections which can be difficult to reach (bends, pipes, pumps) where the presence of micro-organisms is hard to measure and control. Without specific water treatment, biofilm can develop and proliferate all the way to the rinse tanks.

Prevention, through appropriate pre-treatment of the water, is thus essential, even if water is heated to 70° and constantly circulated. Such a pre-treatment solution, supplied by NGL, has been successfully implemented for the final rinse of medical devices prior to entry into the cleanroom at Charles PERY, a manufacturer of medical implants and instruments in France.

To achieve a quality of purified water in bulk (PBW) of pharmacopoeia level PE7 (see panel), NGL supplies equipment to filter and remove the various mineral, organic and bacterial contaminants found in drinkable water.



  • Pre-filtration on sediment filters.
  • Water softening.
  • Reverse osmosis to remove most organic matter, colloids, suspended particles and minerals.
  • Dionisation resins to remove dissolved mineral residues.
  • UV lamp to remove any “pioneer” bacteria present in the water.
  • Hot water circulation loop at 70°, piping made entirely of 316L steel, seamless, without weldings and stagnant sections, cleaned and passivated (ASTM G93 standard) to pasteurise the water.
  • Continuous filtration of recirculated water through 0.2µm and endotoxin (0.05µm) filters to ensure microbiological parameters concentration meets standards at point of use.


Water in bulk (PBW)

PE 7

Production mode

All techniques are allowed

Supply water

Water intended for human consumption according to Directive 98/83/CE


Clear and colourless liquid

Total organic carbon

≤ 0,5 mg/L

Bacterial endotoxins

< 0,25 UI/mL

Conductivity at 20°C

≤ 4,3 µS/cm

Conductivity at 25°C

≤ 5,1 µS/cm


≤ 0,2 ppm



Heavy metals

≤ 0,1 ppm

Counting of microbiological germs

≤ 100 UFC/mL


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