I'd just replace it with something decent. With that thin lining separating you and the ground your rig is on from a biohazard, it is a lot easier with money/time to replace than deal with potential "RV the movie"-like accidents.
Of course, you could go with a macerator pump and reinforced garden hose -- it takes a lot more punishment to get that thing to leak.
I don't want to be the guy who causes the complaint similar to what was posted a few days go about dumping black water on the campsite.