Abstract: The present invention is directed towards bacteriophage therapy, the treatment of infectious diseases, caused by pathogenic bacteria, using specific bacteriophages. The purity of bacteriophage preparations has been a major obstacle for their therapeutic use in the past. Current purification methods are only suitable for low-scale production, as they are work and cost intensive. Disclosed is a method and machinery to purify crude bacteriophage preparations in large scale and fully automated, resulting in highly pure (toxin free) and highly concentrated bacteriophage preparations, suitable for agricultural and clinical applications.