I can't speak for your company and co-workers, but I do know that mine knew about me before I did.
There I was thinking the eyedrops, the dragging myself in every day, the shakes from too much caffeine (my excuse), the breathfreshener, all of those things were my cover.
When I came back from rehab and was asked by the management to keep quiet (which wasn't my intention) because of my position, I found out that people were insulted by my pretence because it was so obvious. I also have a co-worker who is missing so many days, he is so far gone, everybody talks about his drinking. I'm ashamed to say that I probably looked the same.
Shakes, sweats, forgetfulness, the smell of drink, etc. etc. I tried reaching out to him by simply admitting to my past drinking, but he is not ready I guess.
It is your decision to come clean with them and yourself of course. My company was very supportive and has been in other cases as long as the individual was willing to help themself. Be strong and good luck.