| I heard from a guy who worked in a place that had a
| pump assembly at the toilet in the shop. He says that
| he could identify the persons using the toilet by the
| smell after each one. He tried to convince them to use
| the toilet in the other section of the building, with
| little success.
|
| Point of mention this, is that if you download into
| the toilet, you might want to find a way to run enough
| water to eject the material, rather than leave it in
| the tank.

The tank I dealt with is fairly big. Maybe 30"x40"x7".
It's not just a one-use holding tank. I never noticed
any smells. There's just the sealed intake and a pipe
outlet. The tank itself is one-piece. So it's no more
likely to leak than normal drain pipes or toilet seals.
I also wonder about the reasoning of your friend. If it
smells just after someone uses it, why would one think
that's due to a leak in the tank? Wouldn't it make more
sense to check for smells when it hasn't been used for
some time?