At inge GmbH, ultrafiltration membranes are manufactured using the wet spinning process. In the course of this process, which is based on the principle of diffusion, polymers, solvents and other process substances become part of the process water system. The process water treatment system is operated with the aim of recovering and reusing water and an organic solvent. The system includes chemical and physical processing methods. The final treatment stage consists of a rectification plant. During this thermal separation process, unintentional precipitation of dissolved solids occurs in the water-separating rectification stage.\nIn this thesis, the precipitated solids in the column and in the economizer of the first rectification stage are examined for their composition and the process of their formation. Examination of their solubility in water and in acidic and alkaline liquids shall provide information on the possibility of using Cleaning In Place processes. To discuss further possible changes in the physical system of production-related water use and water treatment, its components are discussed and illustrated, and the interactions within the systems components are explained using water analyzes.