I just found this thread. I had to laugh when I read this because I did the exact same thing! I lived on the road in professional transport. I had a porta-potti my mother borrowed me. I'd had a very long day driving and went to use this thing. Apparently I either didn't latch the two halves properly or the seals sprung a leak because it spewed whiz everywhere. I was seriously cranky and mad! I had it (thankfully) sitting on a rubber-backed rug so that was easy to take out and run through a washer.
I immediately called my mom and said, "This $*%* sprung a leak! Do you want it back?" She emphatically said, "NO!"
Like a toilet-bouncer I promptly dragged it out of the truck by it's toilet shirt-collar and threw it rudely in the nearest dumpster. It hit the bottom with a satisfying thud. Gone that fast.
The setup I ended up using and is still my go-to when ya gotta go:
A luggable loo (5 gallon bucket) with a lid. I double lined this with at least one black garbage bag, the other could be white. I added a few cheap, generic disposable diapers turned inside out and a camping toilet toss-in packet purchased from the WalMart RV section. I kept a roll of the small 4 gallon bags (Ruffies?) handy for...solids. When done, the small bag was tied up and tossed in with the rest. With the lid that snapped down and the diapers, spills and odors were not a problem.
This setup would last me around a day to a day & a half.
I found that I had more leakage problems with the 'ultra-flex' type bags, so I ended up staying away from those. I would look for the thickest mils bags. And I've had problems with the larger rolls of the Ruffies-style bags occasionally splitting up the side if you get a bad roll so I wouldn't use those for bucket liners - but for a solids bag the little ones work well.