Accompanying the monitoring of the ozone test procedure with bioassays

Since the legal amendments to the Swiss Waters Protection Ordinance came into force on January 1, 2016, selected WWTP must be equipped with an additional treatment stage. In terms of sustainable water protection, it must be ensured that these additional wastewater treatment methods both effectively remove trace substances from the water bodies and do not generate any toxic intermediate or by-products.

Within the "Strategy Micropoll" (2006 to 2010), among other things, bioassays were used to investigate which methods are particularly suitable for upgrading wastewater treatment plants with a fourth treatment stage. The use of bioassays served on the one hand to investigate the efficiency of the trace substances reduction and on the other hand to assess whether harmful transformation products are generated by the additional treatment step.

Bioassays are currently still being used in the upgrading of WWTP with the fourth treatment stage, for example to assess the possible effects of the ozone test process.