Physico-Chemical Effluent Treatment

Elimination of heavy metals from untreated water using chelate-forming cation- and weak base anion exchange resins

Results obtained from tests conducted on a semi-industrial scale suggest that this process would be suitable for commercial application. Exchange resins with a phenol-formaldehyde matrix appear to provide a particularly appropriate solution to the problem of the increasing contamination of groundwater by heavy metals.


Heavy metal contamination of groundwater represents a growing problem for the supply of drinking water.  In places, poisons such as lead or cadmium and allergens such as nickel are present in concentrations of up to 200 μg/l, and must be reduced to concentrations of less than 20 μg/l in order to meet the requirements of drinking water regulations.  In contrast to the industrial waste water treatment sector, where heavy metal elimination technology represents the state of the art, the drinking water sector has no selective processes for the effective removal of heavy metals.

The objective of this research project was the investigation of the use of weak base ion exchangers for the removal of heavy metals in the laboratory and on a semi-industrial scale, with a particular focus on nickel.  Commercially available resins have been used for this purpose.


  • Using an ion exchanger based upon a phenol-formaldehyde matrix (DUOLITE A7), it has been possible to obtain useful results for the commercial application of the process.
  • Using a filter with a filter bed volume of 45 l, it has been possible to achieve filter velocities of up to 10 m/h.  For higher velocities, a larger filter bed volume would be required.
  • No problems regarding chemical or mechanical stability were observed during continuous operation over a period of 28 months.  The bacterial count also lay well below limit values.  No coliform bacteria or E.coli have been detected.

Project Participants

Implementing Institution

Stadtwerke Mönchengladbach GmbH

Cooperation partner

Forschungszentrum Karlsruhe GmbH, Institut für Technische Chemie, Bereich Wasser- und Geotechnologie (ITC-WGT)

More Project Informations

Project title:  Process technology for the drinking water abstraction by the elimination of heavy metals from untreated water using chelate-forming cation- and weak base anion exchange resins

Project number:  02WT9760/4

Project period:  1998 - 2001

Project region:  Germany (North Rhine-Westphalia)

Project contact:

Herr Dipl.-Ing. Rutten

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Source: German National Library of Science and Technology Hannover (TIB)