Greetings!
I'd like to help you out on this project. My name's Chris and I'm an audio engineer from the Boston area, with over a decade of audio and music experience.
From the description, what you need is an audio engineer to take a couple hours (max!) and identify the frequencies which match the fan's and try to remove them, plus some possible surgical editing on the file itself if there weird sounds between voices etc.
My bid is based on an estimated 25-minute file, but my only question to you is this: how long is the file you'd like edited?
Don't hesitate to ask me any questions. I'd like to work with you, and hope to hear from you soon.
All the best,
Chris L
Holbrook, MA