# Rationale for the Combined Use of Biological Processes and AOPs in Wastewater Treatment Tasks
## 2 Materials and Methods  
### Experimental Electrotechnological Water Treatment Complex  
To treat the water solution of the closed-loop water supply plant for the cultivation of hydrobionts, the parallel AOP module was connected to the existing industrial equipment (Figure 3). The processes of mechanical purification (filter sieve and laminar settling tank), ozonation, UV irradiation, and electrolytic anodic oxidation were implemented in the electrotechnological water treatment complex (Figure 4). The stages of experimental flow-through treatment were as follows (Figure 4):  
* Mechanical separation of pollutants (filter sieve and laminar settling tank);
* Water supply to the electrolysis unit for anodic oxidation of pollutants;
* Ozone supply to the reactor-mixer to implement the photolysis process (synergistic oxidative process of ozone and ultraviolet irradiation);
* Analysis of quality indicators of water solution by the concentration of nitrogen compounds (i.e., ammoniacal nitrogen, nitrties, nitrates). Figure 3: Scheme of connection of the AOP module to a closed-loop water supply system for the cultivation of hydrobionts. To ensure the course of electrolysis processes, a diaphragm electrolyzer with an inactive membrane (anode and cathode were made of electrode graphite; in the anode were additional poured shavings), a volume of 3 L at a current strength of 10 A was used; electrolysis time was 120 s.  
The ozonator provided ozone generation with a production capacity of 6 g/h. The UV-irradiation unit operated at a \"germicidal\" wave with a frequency of 245 nm, a power of 55 watts, and a photolysis treatment time of 20 min. Water treatment quality was determined by the concentration of nitrogen compounds in aqueous solutions according to [PERSON]'s methodology [29]. Two types of CLWSI circulating water were treated:  
* Type 1: Aqueous solution 14 h after feeding the fish and 8-fold turnover through a filter sieve and laminar sump: characterized by translucency of 87.3%; no fat stains;
* Type 2: Aqueous solution 2 h after feeding the fish and 1-time turnover through a filter sieve and laminar sump: characterized by translucency of 72.4%, with significant fat stains caused by residual feed and a yellowish hue caused by the presence of organic colloidal particles. Methods of Microbiological Research of the Effects of Antibiotics and Surfactants on the Biocenosis of Activated Sludge  
The activated sludge was taken from the operating treatment facilities of the MHP \"Orel-Leader\", which is the largest integrated poultry farm in the Dnepropetrovsk region. In 2012, it commissioned an anaerobic digester in the village of Elizavetovka, which produces 20 million m\({}^{3}\) of biogas annually, from which it continuously produces 5 megawatt hours of electricity, as well as 119,000 million BTU of recovered heat. To Study the resistance of activated sludge biocenosis to antibiotics, we used the agar diffusion method to determine the sensitivity of the activated sludge's biocenosis to a widespread group of antibiotics [30]. Nutrient medium was prepared on nutrient agar. The nutrient agar (manufacturer LLC \"Farmaktiv\", Kyiv, Ukraine) was composed of enzymatic peptone (10 g/dm\({}^{3}\)), microbial agar (10 g/dm\({}^{3}\)), sodium chloride (5 g/dm\({}^{3}\)), and yeast extract (2.53 g/dm\({}^{3}\)). The stages of using nutrient agar were:  
1. Dissolve 28 g of the medium by heating in 1 L of purified water;  
2. Boil for 2-3 min until all components are dissolved;  
3. Autoclave for 15 min at 121 \({}^{\circ}\)C;  
Figure 4: The structural diagram of the electrotechnological water treatment complex using AOPs (ozonation, UV irradiation, and electrolytic anodic oxidation). 4. Cool to 45 \({}^{\circ}\)C and pour into sterile Petri dishes. pH was maintained at 7.3 \(\pm\) 0.2 under 25 \({}^{\circ}\)C.  
The seeding was performed by looping (stroking seeding) according to [PERSON]'s method. On the outer side of the bottom of the Petri dish, we drew delimiting lines with nutrient agar, dividing it into 4 sectors.