# Rationale for the Combined Use of Biological Processes and AOPs in Wastewater Treatment Tasks
## 1 Introduction
Spatial distribution analysis showed that samples collected from the same sampling locations were similar to each other in terms of antibiotic resistance and biodiversity; this indicates that antibiotic resistance spreads locally over small distances in biofilm [17]. A study by [PERSON] et al. [18] proposed an electrodialysis (ED) system, named ED anode, which can be used in situ for the electrochemical removal of antibiotics during nutrient (N and P) recovery from animal manure digestate, which requires further research in order to optimize the system's mode of operation under different environmental conditions [18]. In a study by [PERSON] et al. [3], the distribution of anionic and nonionic surfactants was studied in groundwater in the UH 05.56 hydrologic unit (Spain). Surfactant concentrations ranging from 1.1 to 9.7 \(\upmu\)g/L were detected, with the highest concentrations detected in 3 of the 10 wells sampled. The aquifer was dominated by oxic conditions and pH ranges from 6.5 to 9. The presence of surfactants was the result of agricultural irrigation with water from the river mixed with treated wastewater. It is worth noting that surfactants are currently used in pesticides, so their presence is also due to agricultural management [3]. Figure 2: Thematic areas of publications in the field of wastewater treatment according to the Scopus database. A study by [PERSON] et al. [19] focused on evaluating the performance of two types of domestic wastewater treatment plant: a wetland wastewater treatment plant (ORS type), and an SBR-type wastewater treatment plant (SBR-K-6 type). At the ORS- and SBR-K-6-type wastewater treatment plants, the anionic surfactants were removed up to 98 and 88%, respectively. A lower removal efficiency was achieved in the case of non-ionic surfactants, which reached 76% for the ORS-type facility and 56% for the SBR-K-6-type facility; this demonstrates the need for comprehensive solutions that address the technological mode of operation of treatment plants [19]. Despite numerous publications on the problems associated with proper management of this type of wastewater treatment plant, none of the studies take into account the operating conditions of activated sludge and, in particular, the effects of surfactants on activated sludge. The evaluative analysis conducted shows that the treatment and daily care of surfactant concentrations in wastewater can harm the performance of domestic wastewater treatment. It is very important that these products can be used in care after the dilution recommended by the manufacturers. Research has also shown that sludge is highly resistant to single doses of wastewater with high concentrations of anionic surfactants [20]. However, such concentrations should not be routinely fed into domestic wastewater, due to limited activated sludge capacity and limited adsorption of biodegradable surfactants. It is also recommended to periodically check the content of anionic surfactants in treated domestic wastewater, due to their negative effects on soil and vegetation [20]. A separate direction has been the use of advanced oxidation processes (AOPs) [21] for wastewater treatment tasks, which include several advanced technological solutions, such as homogeneous and heterogeneous photocatalytic processes, ozonation, variants of the Fenton process, ultrasonic treatment, wet oxidation, oxidation in supercritical water, plasma processes, ferrite and persulfate technologies, use of ionizing radiation, and microwave treatment. The use of [PERSON]'s reagent when irradiating the aqueous solution with ultraviolet light (wavelength 254 nm) and controlling the pH values allows for deep destruction of organic pollutants, with an efficiency of more than 80% [22]. The combination of ultraviolet irradiation (wavelength 254 nm) and the application of hydrogen peroxide (H\({}_{2}\)O\({}_{2}\)), in addition to the oxidation of contaminants, enhances the complex effect of disinfection of the treated medium by at least 20-fold [23].