U procesu prerade nafte nastaju otpadne vode koje sadrže onečišćenja i zagađenja te mogu smanjiti kakvoću priobalnog mora i ugroziti životne zajednice u njemu. Stoga se otpadne vode pročišćavaju prije ispuštanja ili njihovog ponovnog korištenja. U radu su opisane tehnologije obrade otpadnih voda rafinerije. nafte. Dan je pregled njihovog sadržaja te usporedba s propisanim maksimalno dozvoljenim koncentracijama. Uzimajući u obzir i ostale dotoke otpadnih voda u ekosustav Riječkoga zaljeva, moguće je procijeniti relativan utjecaj otpadnih voda iz procesnih postrojenja Rafinerije nafte Rijeka..; Wastewater resulting from the oil refining process, which contains pollution and contamination, may reduce the quality of coastal water and endanger its living communities. Wastewater is, therefore, treated prior to its discharge or reuse. The paper describes technologies for processing wastewater originating from oil refineries. An overview is given of wastewater composition, which is then compared to the proscribed maximum permitted concentrations. Having in mind other wastewater inflow into the ecosystem of the Rijeka bay as well, it is possible to assess the relative impact of wastewater from the processing plants of the Rijeka oil refinery.