Enhance 20-Minute Audio Recording

I have a single audio file, roughly twenty minutes long, that captures an important conversation. The track suffers from persistent static hiss, and I need it cleaned so the voices sound clear, polished, and ready for professional use... (Budget: $10 - $1000000000000 USD, Jobs: Audio Editing, Audio Engineering, Audio Mastering, Audio Processing, Audio Production, Audio Services, Sound Design, Voice Talent)