Urban Waste Water

Drinking water treatment - Alternative materials for the pre-oxidation stage in flocculation

The focus of the studies carried out as part of the project is on drinking water treatment of eutrophic untreated water in emerging and developing countries. To do this, the researchers are testing the suitability of different oxidation agents (ozone, hydrogen peroxide, potassium permanganate, sodium peroxide sulphate) for use in the pre-oxidation stage of flocculation. 

Summary

In emerging and developing countries, water with a high level of contamination and eutrophication is sometimes the only available source for drinking water treatment. Particles are mainly removed by flocculation, and pre-oxidation with ozone improves particle separation. However, as this method and operation of the associated equipment requires a certain amount of specialist knowledge, the project partners are studying the extent to which other, easily available and dosable oxidation agents could be an effective alternative. They are studying hydrogen peroxide (H2O2), potassium permanganate (KMnO4) and sodium peroxide sulphate (Na2O8S2). In addition, the suitability of granulated iron hydroxide (GEH) as an adsorbent for surface water is being studied.

Results:

  • Oxidation with both ozone and H2O2 represents an efficient and practicable option for improving flocculation.
  • While low ozone doses can achieve up to 90% reductions in turbidity, depending on the initial turbidity, the turbidity reducing potential for H2O2 is around 30%.
  • The requirement for H2O2 (<1 mg/mg iron) and the costs for using H2O2 oxidation in flocculation are very low.
  • Experiments with KMnO4 did not deliver clear results.
  • Na2O8S2 showed no influence on flocculation and turbidity did not reduce in any of the tests.
  • Granulated iron hydroxide proved to be unsuitable in the tests for reducing DOC (dissolved organic carbon) by adsorptive removal of NOM (natural organic matter) from surface water. The achievable loads are low compared to other adsorbents. In-situ regeneration of the adsorber material was not satisfactorily achieved with any of the regenerating agents.

More Project Informations

Project title:  Verbundprojekt: Exportorientierte Forschung und Entwicklung auf dem Gebiet der Wasserver- und -entsorgung Teil 1: Trinkwasser; Kernprojekt C: Technische Verfahren (TP C7A: Neue Oxidations- und Sorptionsverfahren zur Entfernung von Partikeln und gelösten Störstoffen)

Project number:  02WT0278

Project period:  2002 - 2005

Project region:  Germany (Berlin)

Project contact:

Herr Prof. Dr.-Ing. Jekel

+49 (0)314 / 25058

+49 (0)314 / 79621

View Publication

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