The sediment and carbon filter cartridges in our house call for annual replacement and I wondered what was inside the big cartridge.
Much to my surprise, the white plastic cap unscrews easily after grabbing the filter in the bench vise and applying a strap wrench:
Water enters around the perimeter of the cap, flows through the media in the cylindrical cartridge, and emerges near the center at the other end. The filter is upside-down in the vise: the cap is on the bottom of the cartridge when it’s installed in the filter housing.
The brown stuff looks a lot like sand, but is probably KDF-85 media acting as a prefilter for the carbon:
The white fiber pad separates the KDF-85 from the carbon granules filling the rest of the filter:
Atypically, I couldn’t think of anything to do with the empty cartridge, so I screwed the lid back on and lowered the whole mess into the trash can.
Now I know what’s inside!
The Smell of Molten Projects in the Morning 