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.
Even Fox Cutter's estimate is 250 words per page isn't useful. If you have a lot of dialog, you may have pages with a lot less than 250 words on them. If you're a wordy writer, you may have pages with a lot more than that. Even the complexity of the words you use affects how many words are on a page. You 50,000 word manuscript may be half the page length of another authors 50,000 word manuscript. The short answer: Don't worry about page length. Worry about word length.