Audio Files Noise Reduction

I have 7 WAV audio files that need to be cleaned up, each between 24-43 minutes in length. The primary issue is background noise. I'm looking for a professional with experience in audio editing and noise reduction to enhance the sound level and quality. Since these are recorded at a conference, I expect to have some background noise, just want to see if it can be brought down some.

File1 = 33 minutes
File2 = 24 minutes
File3 = 27 minutes
File4 = 25 minutes
File5 = 39 minutes
File6 = 37 minutes
File7 = 43 minutes

Ideal skills include:
- Proficiency in audio editing software
- Experience with MP3-WAV files
- Ability to reduce background noise effectively
- Attention to detail

Included is a WAV file sample of one the actual recordings.
Please provide examples of similar work you've done in the past.