To give you a little feeling how this works, these walls here are perforated so it’s easy for air to move through.
There’s a similar wall on the inside, opening a tube where the air goes through.
There’s a fan right here which will suck the air through the system and blow it out towards the top.
As the air goes through, it goes through this layer in between here which is filled with this packing material you see here.
This is material that is very open.
If you blow air through, it easily goes through.
They are wetted with the sodium hydroxide solution.