Abstract Increased production and consumption of drugs influences the pollution pharmaceuticals. Recent years have seen a significant increase in the consumption of non-prescription medicines, among which, are a large group of non-steroidal anti-inflammatory drugs (NSAIDs). Research conducted in Poland and abroad showed the presence of NSAIDs, both in treated wastewater in surface waters and drinking waters. One of the most frequently detected drugs in the environment is diclofenac, belongs to NSAID. Its concentration in surface waters range from 9 to 3363 ng/L. Traditional wastewater treatment plants are not specialized enough in removing the pharmaceuticals and their metabolites, and with purified wastewater are introduced into surface waters. Diclofenac concentrations in treated wastewater range from to μg/L, the average removal efficiency is about 40%.