The Advanced Zakuulan Trash Recepticle decoration can be dropped from Eternal Command PacksUltimate Cartel Packs, which were released on the Cartel Market and bought with Cartel Coins. Cartel Packs, including the Eternal Command PackUltimate Cartel Pack, include a random selection of items from the Eternal Command Ultimate Cartel collection of items. You aren't guaranteed to get an Advanced Zakuulan Trash Recepticle decoration from a Eternal Command PackUltimate Cartel Pack, but it is one of the few ways to get an Advanced Zakuulan Trash Recepticle deco apart from buying it on the GTN from another player.
If you're looking to get a Advanced Zakuulan Trash Recepticle, the easiest way to get it is to head to the Galactic Trade Network (GTN) in SWTOR and buy it with credits from another player. If it's very rare and not available on the Cartel Market, you could try buying from the GTN and hope you get it.