The present invention is for processing fluids, especially waste streams from nuclear power plants, and other fluid media that may be carrying valuable or useful substances, in order to collect the substances. The system uses sequential filtering and multiple passes to concentrate the substances, which allows the system to collect virtually all of the substances of interest to the user while reducing the volume of both the unwanted materials as well as the desired materials desired without affecting the purity of the fluid after processing. Additionally, the collected substances can be processed in-place, and without requiring any thermal processing prior to disposal of unwanted substances, or for the recovery and/or reuse of valuable substances.