There are many special achievements in "The Servant of the Lake," and Garbage Disposal is one of them. To unlock this achievement, you need to go to the [Night Shift] level, head to the balcony, and throw three pieces of trash over the railing. It's not too difficult.
How to Get the Garbage Disposal Achievement in Rusty Lake: The Servant of the Lake
Garbage Disposal
Garbage Disposal
In the [Night Shift] level, go to the balcony and throw three pieces of trash over the railing.
Related Guide: How to Get the Clean Window Achievement in "The Servant of the Lake"