Economical and efficient treatment of municipal wastewater (KOV) is necessary because wastewater participates in the hydrolysis cycle, the circulating cycle of elements and represents the living environment of flora and fauna. The main aim of this paper was to examine the efficiency of the ultrafiltration UF membranes during the treatment of municipal wastewater by ultrafiltration. UF was performed with MW membrane at 2 and 5 bar, respectively. There was a change in the flux over time with the irreversible membrane fouling of the MW membrane that was read from the flux and was 78.71 %. Fouling of the GK membrane was negligible and therefore proved to be a better choice during processing. Monitored parameters include pH value, turbidity, electrical conductivity, chemical oxygen demand (KPK), biochemical oxygen demand (BPK5), total carbon (TC), inorganic carbon (IC) and dissolved organic carbon (DOC) of municipal wastewater and the obtained permeate. The composition of the wastewater and the content of each substance was determined by qualitative and quantitative analysis using an ionic chromatograph to determine the presence of cations (Ca2+, K+, Na+, Li+, NH4+ and Mg2+) and anions (F-, SO4 2-, NO3 -, Br-, Cl- and PO4 3-). The obtained permeate meets the limit values prescribed by the Ordinance on Limits of Wastewater Emissions (NN 60/2013). The ultrafiltration of the KOV satisfied the legal requirements, which confirms the efficiency of the UF membranes and UF as an effective membrane separation process during KOV processing.