In the experiments with aerobic bio-oxidation only the aerobic bioreactor
was used. The activated sludge was obtained from Kohtla-Järve Wasterwater
Treatment Plant (WWTP). In the combined treatment studies (biological
oxidation with ozonation) the re-circulation system was operated.
The experiments of post-ozonation were conducted in a 0.9-L semi-batch
glass reactor with continuous gas flow-through. Ozone-air gaseous mixture
was generated in the ozone generator OZON-2M.
For the experiments of aerobic bio-oxidation with ozone injection directly
into the activated sludge in the bioreactor, the laboratory equipment
was rearranged: the ozonation column in the re-circulation system was replaced
with a bubble reactor, where the distilled water was saturated with
ozone. This water, containing dissolved ozone, was led directly into the activated
sludge. The experiments were carried out at the same organic load as
in the combined process. The sludge activity was characterized by the oxygen
uptake rate.