I have this style cassette potty in my off-road popup. It has a 6-gallon removal cassette with wheels which allows me to tote it the bath house and pour down their toilet...
We flush ours until the flush runs out of water and that tells us the cassette is full. Then we pull out the cassette and tote it off to the restroom and pour down their toilet...
There is no way you can modify this. everything goes into the cassette... My POPUP trailer only has a FRESH WATER TANK. I have to capture all of our waste sink water and carry off to the bath house and pour down their toilet.
We only use our cassette pottie just for number 1 and do a standup wash-up at the sink to bathe. Never did a shower using the cassette shower combo as there is only enough room inside it to just sit on the pottie stool and do a sit-down shower with a hand spigot.
I am assuming this is not a JOKE post...
Those cassette potties are not for heavy usage...
Starcraft 14RT OFF-ROAD POPUP
Roy Ken