The presence of pharmaceuticals in the environment is increasing daily because of the bigger use of it in health care and veterinary medicine, and the most of it is getting continuously released through the sewerage system which makes it important to remove it effectively because of the negative impact they have on our environment. Membrane processes have been shown as an effective way of removing pharmaceuticals from wastewaters, but one of the main problems of membrane technologies is the disposal of retentates (concentrates). Contaminants in the retentate can have a big effect on our ecosystem and on the quality of water that is close to the location of disposal. This paper examines anthelmintic removal from retentate by adsorption on a granular activated carbon (GAC) and by photolysis. Besides the processes of adsorption and photolysis, the effectiveness of membrane processes on separation of mebendazole from water through RO/NF membranes was also examined. The efficiency of pharmaceuticals removal from water depends on size of membrane pores and size of pharmaceuticals, interaction between pharmaceuticals and membrane, and physicochemical characteristics of pharmaceuticals. It is determined that dominant mechanism was the mechanism of exclusion depending on the size. The FTIR analysis results showed interactions between membrane and pharmaceuticals, especially in membranes with bigger pores and bigger flow. It is proven that smaller flow rate and bigger height of the fixed GAC layer enables better adsorption during column adsorption due to more adsorption sites and better contact of the adsorbent and adsorbate. Photolytic catabolism of pharmaceuticals is examined by artificial sun light over 2 and 24 hours for different concentrations, but it did not result in complete degradation of mebendazole but in formation of new degradation component.