If you need to dry it out in a hurry, you could spread out a tarp in a room you can close off. Then spread out the substrate on the tarp as thin as you can. A overhead fan will speed up the process. Or just buy one of those big and deep rubbermaid containers to store the substrate in and turn it every so often with a big stick.
If you live somewhere where it is sunny, you could do the tarp thing outdoors on a table. Not on a windy day, though, LOL !!