The comparative experimental study has been performed of removal of pharmaceuticals such as paracetamol and ibuprofen from aqueous solution by ozonation and photochemical degradation in several types of reactors. Ozone, oxygen, and hydrogen peroxide were used as oxidizing agents. Heterogeneous photocatalysis was carried out in the presence of anatase type TiO2 catalyst. To determine the amount of radiation emitted by the UV lamps and transferred into the reactor, chemical feroxioxalate actinometric experiments were performed. The degree of the pollutant removal was monitored by HPLC, COD, BOD5, and TOC. An ecotoxic biological test of process products with Parachlorella kessleri was also evaluated. The results indicate that the removal of both pharmaceuticals is most effective by heterogeneous photocatalysis. In the UV processes, the degradation rate increased considerably when H2O2 was added. However, the addition of peroxide into the ozonation system improved the ozonation only slightly. All products of the processes tested showed improved biodegradability according to the BOD5/COD ratio and low toxicity to Parachlorella kessleri.

The sulphur-based autotrophic denitrification process utilizing Thiobacillus denitrificans was studied experimentally as an alternative method of removing nitrates from industrial wastewater. The objective of the work was to examine the effect of ferric iron addition to the reaction mixture and determine optimal dosage for specific conditions. All experiments were carried out in anoxic batch bioreactor, and elemental sulphur was used as an electron donor. Compared to the control operation without ferric iron addition, significant increases in nitrates removal were demonstrated for the concentration of ferric iron equal to 0.1 mg L -1 . However, under these conditions, increased nitrite content was detected in the reaction mixture which exceeds the limits for drinking water.