The usage of membranes in wastewater treatment often leads to problems with scaling and fouling, which results in an irreversible loss of membrane permeability. Various pretreatments as well as mechanical and chemical cleaning possibilities are described and evaluated in order to ensure continuous operation. The cleaning has been performed by a sequential backwash with filtrate. In addition, the membrane was cleaned chemically to restore the flux to an acceptable level. The effect of chemically enhanced backwash (CEB) and cleaning in place (CIP) has been considered in more detail. The UF membranes are typically cleaned by soaking in alkali, acids and/or oxidizing solutions. Sodium hydroxide (NaOH), sodium hypochlorite (NaOCl) and acid sulphur (H2SO4) were used as cleaning agents. Furthermore, the impact of pre-treatment by pre-ozonation and subsequent coagulation on the performance of a polyether sulphone ultrafiltration membrane has been investigated in a pilot plant. Ozone is used in water treatment for the oxidation of organic substances, which leads to a reduction of organic fouling. A subsequent coagulation is applied to form stable aggregates out of biopolymers, which are most relevant for membrane fouling in order to backwash them easily from the surface and the membrane pores. Both pre-treatments have an influence on an improved filtration performance. The scope of the current paper is to critically evaluate the impact on the hydraulic and chemical treatment of an organic membrane and to find out which cleaning strategy is the best against membrane fouling.