Using porous membranes in areas like process water treatment nowadays is considered established as a process. This technology is - besides the treatment of drinking water which is done for many years now using ultrafiltration membranes - especially utilized for the production of highly pure water in sectors like pharma and electronics as well as for the removal of particles, bacteria, viruses and pyrogens. Due to the specific properties of C-CUT hollow fiber modules like e.g. maximum membrane surface in a compact housing and excellent cleaning conditions, this type is widely used in process water treatment. A further conditioning to reach higher degrees of purity then can be achieved via S-CUT spiral wound elements.