Infiltration Posted on 1st December 201521st March 2022 by ThePD (The Project Definition) Infiltration is a permeation that moves slowly into a substance, place, system, or organisation. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in Engineering and tagged plant, process. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.