You would need to empty into the septic system via a direct connection. Certainly couldn't just dump on the ground or the smell would run you out. Remember you don't HAVE a septic system in your RV, it is merely a storage tank that you empty into a sewer or septic connection. Make certain that their system can handle the gallonage you would be dumping all at once since it's NEVER a good practice to try to empty in small batches. There must be a sufficient amount of water in your holding tank to flush solids across the bottom and out of the tank and with out enough water your holding tank will very quickly build up solids and become clogged (not to mention very smelly)
Good luck / Skip