## 3 Results and Discussion
### Development of the Qualitative Composition of the Biopreparation
In the next step, the decomposition rate of individual drugs in the presence of a mixture of paracetamol, ibuprofen, naproxen, and diclofenac was determined. Paracetamol was degraded the fastest in systems designed in this way (28 h) (Figure 2A). The ibuprofen degradation occurred within 31-32 h, regardless of the system used (Figure 2B) (Figure 2C,D). Naproxen was best degraded in the V3 system, while diclofenac was in the V1 system. However, the decomposition of the tested drugs with two aromatic rings took significantly longer than the decomposition of single-ring drugs [2,3]. No complete degradation of any of them was observed after 32 h. This is due to the high durability of such structures. Naproxen is a derivative of naphthalene. Hence, its degradation involves enzymes engaged in the degradation of two fused aromatic rings. Only after the degradation of one of them is the activity of typical dioxygenases cleaving a single aromatic ring possible, which significantly extends the degradation process of naproxen [39,43]. On the other hand, diclofenac has two aromatic rings linked together by an amine bridge. Although the literature indicates a relatively easy cleavage of this compound into two rings, the deactivating effect of chlorine substituents in diclofenac significantly slows down the degradation process [1,2,4]. An interesting phenomenon is the long period of adaptation of the tested systems to the degradation of naproxen. Noticeable decomposition of naproxen occurred only after the 21 st day of culture. [PERSON] et al. [44] indicate the hydrophilic nature of the sponge, which excludes the sorption of naproxen on its surface and diffusion inside [20]. The poor distribution of naproxen is probably related to the hydrophilic nature of the sponge and the large condensed aromatic system of naproxen. As a highly hydrophobic compound, naproxen probably diffuses slowly through the sponge structure, significantly reducing its availability to immobilized cells. Only the complete formation of a biofilm penetrating the structure of the sponge allows better contact of the drug with the bacteria. As a consequence, this leads to faster degradation of naproxen. Distribution analysis of the 1000 ug/L mixture of NSAIDs tested showed only minor differences between the systems (Figure 3A). The highest decomposition rate in 24 h was demonstrated for the V3 system, which was 485.5 ug/L. The analysis of phenol decomposition, as an indicator of the efficiency of the preparation in the treatment plant conditions, also showed no significant differences between the systems (Figure 3B). Due to the lack of apparent differences in the degradation of the analyzed substances, the V3 system containing all four strains was selected for further research. The choice was dictated by the fact that the preparation is  
Figure 3: Degradation of a mixture of drugs (**A**) and phenol in the presence of 1 mg/L drugs (**B**) in cultures containing systems of V1, V2, and V3 bacterial strains. ultimately tested as a preparation supporting the activated sludge of sewage treatment plants, which receive various pollutants. The rich species composition ensures greater versatility of the proposed preparation. Choosing the Optimal Amount of Carrier with Immobilized Biomass and Effect of Phenol on the Degradation of a Mixture of NSAIDs and Paracetamol  
The following research stage included selecting the optimal amount of carrier with immobilized biomass for biodegradation processes. The preparations contained the KB4 strain at 17 mg/g of the carrier, the B1(2015b) strain at 15 mg/g of the carrier, the KB2 strain at 18 mg/g of the carrier, and the S5 strain at 20 mg/g of the carrier. Figure 4 shows the carrier with immobilized strains constituting the basis for the preparation construction. Three systems were proposed in the study. The first system contained a carrier at 0.6 g/L, the second at 1.2 g/L, and the third at 1.8 g/L.