Wastewater treatment is an indispensable part and the final segment of the entire public drainage system and SBR and MBR treatment technologies are one of the most common in this industry. In this thesis, an analysis of the operation of two different technologies installed at the WWTP Delnice in the Republic of Croatia (SBR) and the WWTP Siffiano in the Republic of Italy (MBR) was performed. On the constructed WWTP that have been in operation for several years, an analysis and assessment of the operation of each of the technologies was carried out, according to the given criteria that are normally applied to variant solutions for selecting the optimal technology. The goal of the research was a realistic presentation, analysis and evaluation of the entire technological process with a presentation of investment and operating costs obtained from the manager. In the descriptive part, the purification process is divided into mechanical pretreatment, biological purification and treatment of excess sludge. The analysis itself includes the parameter of investment value, operating cost, spatial component, control and process complexity and the purification effect, which are evaluated differently and lead to the final result. Looking at the complete analysis, it was concluded that these are equivalent technologies and that it would not be realistic to give preference to one over the other. In the conclusion, the theoretical possibility of replacing technologies and related implications on the result of work and the costs of individual WWTP is also discussed. The paper also contains a shorter analysis of the comparison of these two technologies at WWTP La Center in the USA.