Tannery in Farmstead World — building in the game, and what it is on a real farm.
A tannery turns animal hides into leather by preparing, tanning and finishing them.
Its wet processing creates wastewater that needs treatment before discharge.
Leather manufacture starts with animal hides. Preparation removes unwanted material; tanning stabilizes the hide, and finishing produces leather for use in manufactured goods.
Sources: [1]
Tannery wastewater can contain suspended solids, sulfide and chromium, depending on the process. Treatment and discharge controls are part of operating the workshop, alongside the value recovered from hides.
Sources: [2]