Reduce background noise

Hi everyone,

I had a lot of interview clips with heavy background noise that I'm expected to get rid of as much as possible. I downloaded Adobe Audition less than a week ago and have been struggling to achieve the desired effect of noise reduction. Often I am left with an underlying electrical sound. And when I try to get rid of it, the speech becomes really unnatural.

Here is the link to some parts of the audio: https://livelancsac-my.sharepoint.com/:v:/g/personal/buivn_lancaster_ac_uk/EZfY_fCg4eREj2fPfz6d5FEBTcsVZS4KiHe0Cj_VKAfQL… 

I would really appreciate any advise on how to improve the sound quality.

Thanks a lot!