Water is the most vital part of the environement, is making an irreplaceable raw material and access to clean water sources is an increasingly pressing global problem. The diploma thesis deals with the effect of microfiltration on the efficiency of the cleaning process. It focuses on waste water treatment, the selection of appropriate processes and procedures in the purification process, and also the treatment of the purification process using the membrane system introduced in the wastewater treatment plant in Veľký Slavkov. In the purification of waste water, it is necessary to achieve that undesirable components to reach the lowest concentration or to completely eliminate. Efficiency was assessed through selected physico-chemical indicators of water quality from inlet to waste water treatment plant and water before microfiltration and water after microfiltration - discharged to the recipient. Based on the efficiency calculation, it has been found that the inclusion of microfiltration in the purification process will increase the efficiency of wastewater treatment in most physicochemical indicators.