The Victoria SPCA has always sent the animals it kills to the landfill. A few years ago a person was hiking and found a bunch of dead animals in a wooded area (not by the landfill). The municipality/police traced the bodies back to the disposer and the company that was transporting the dead animals was fined for dumping them. I can't remember where it was the bodies came from, it may not have been the SPCA, it may have been another pound.
It was so disgusting to know that animals are treated this way. When I tell people that is how the SPCA disposes of the animals it kills, they at first don't believe me and then are completely disgusted.