Those toilets are their own internal holding tank.
They chop up the waste and use blue goo to color the water as it is used to flush .
Sort of like a commercial aircraft setup.
They will need a deck fitting for pump out , or you need to go miles out to sea to overboard discharge , the usual method.
Sadly they all will smell, even with fresh blue goo no stink ..
A better onboard holding system is available, similar, with the waste held below the toilet that doesn't stink.