The Waste Disposal - or at least, a part of it as Garbage Hold Room 08 - is located on M Deck.
It was here that Talkie Toaster was placed out of the sight of the crew for two decades, gathering dust, as Dave Lister found him incredibly annoying. However, Lister and Kryten were forced to retrieve Talkie Toaster from the Garbage Hold since they needed his vote in a "machine president" election between Kryten and Arnold Rimmer. The stakes were high, since the election would decide who would lord over Red Dwarf.
To gain Talkie's favour, Lister had to promise to take Talkie Toaster back up to the sleeping quarters and eat six rounds of toast, a toasted bagel and a toasted tea cake every morning. M Deck proved to be the "swing deck" in the election, and Talkie Toaster's vote clinched the election in the favour of Kryten.
However, soon after Cat took Talkie Toaster back down to Garbage Hold 08 and also tricked Rimmer into going in, before sealing him inside. Talkie Toaster rapidly drove Rimmer insane with his contanst and repeated asking of Rimmer for toast. ("Mechocracy", Series XII)