Comparison of different post-treatments of ozonation

Numerous wastewater treatment plants in Switzerland are currently being expanded to include an ozonation stage. Treating wastewater with ozone eliminates many organic trace substances and significantly improves wastewater quality. As a side effect, however, ozonation can produce labile, toxic reaction products that have to be degraded again in an after-treatment stage.

At the Altenrhein WWTP, several bio-tests are used to examine the quality of the wastewater after different after-treatments and thus compare them. Treatment with a sand filter is compared with treatment using differently loaded granulated activated carbon.

Applied test systems

• Combined algae assay with unicellular green algae
• Ames Test