Bad Odor from my gabage disposal and ac

I just moved into an aprtment in Nashville ,Tn about six weeks ago. Few days after I moved in, I notice that the toilet bowl was just foaming. First, I thought my little girl poured soap into the toilet. I was mad at her. Few days later, I noticed that the toilet just started backing up and foaming-this time, my dauther was not home. A few minutes later the kitchen sink started doing the same. Their is this very bad odor that is coming from the gabage disposal in the kitchen.
I have used baking soda and pinesoul to clean the gabage disposal, but the smell just keep coming.
The last one month, I have tried to use my air condition, but the stench that comes from it is just so bad-it smells like sewage. I found out that the apartment have a septic tank not connected to municipal lines. I am not sure if the source of all these problem is the same.
Please, what shall I do to eliminate these problems?

The only thing I can think of is some sort of foaming drain cleaner being poured in from another unit...Contact the LL and let them deal with it...the smell could easily be from a septic system that is not functioning right...you could call the health dept.

Call the landlord

Call the landlord.

It is their problem not yours. Sounds lilke the septic is backing up.

If he/she dosent follow through call the town and talk to the health dept.

Hard to put this all together....but has the A/C been serviced recently? Maybe someone uses some foaming coil cleaner, then rinsed it, and the A/C condensate drain may be connected incorrectly to your sewer system

stopped up drain???

pardon me for intruding...

but it sounds like you
might have a stopped up plumbing system

sometimes when a septic stops up it can actually belch
some pretty nasty odors into the home..

I suggest that you start at the septic

see if their is a clean out in the yard and
see what happens if you take the plug off....