I did it when I got my 1st MH 20yrs ago... (in the flower bed, even). I've seen dire warnings in other threads on here. Will overwhelm the system with volume, wrong chemicals, chemicals will ruin your septic system and on and on. The only thing is can tell you is from my experience (nothing theoretical).
We used our MH to go to the races. My wife and I were out 1 or 2 nights a week from Feb thru Nov. Always dry camped in the race track parking lot and used the water and toilet at will. We would even party with friends from time to time.
I never had any problems with my home septic system in the 15 years I dumped into it and the system passed inspection when we sold the house.