The noun FILTRATION has 2 senses: 1. the process whereby fluids pass through a filter or a filtering medium. 2. the act of changing a fluid by passing it through a filter. Familiarity information: FILTRATION used as a noun is rare.
A sentence averages eleven words; an A4 / letter size sheet averages 32 to 35 sentences. A normal size sheet of paper with a standard layout, based on 80% - 90% coverage contains about 350 to 400 words.
A4 is a document format, as a screen image that's going to depend on the image resolution, for example an A4 document resized to: 72 dpi (web) = 595 X 842 pixels. 300 dpi (print) = 2480 X 3508 pixels (This is A4 as I know it, i.e. 210mm X 297mm @ 300 dpi).