The old wastewater system had one fundamental problem: generic wastewater could be turned back into valuable resources, especially gold and silver. With the right setup, this effectively became another way of creating resources instead of recovering something that had actually entered the process.

One of the main design principles of atrm is to avoid these kinds of resource loops wherever possible. Wastewater treatment should clean up a process and recover water — it should not become an alternative ore mine.

For that reason, the new system converts generic wastewater into cleaned water and mineral filter cake. The filter cake still has a useful purpose and can be consumed in brick production, but it no longer provides a shortcut back to valuable ores.

Selective recovery may return later, but only where it makes sense. Following the Holmium/Iridium approach, a future process could look like:

Gold processing → gold-bearing wastewater → dedicated gold recovery

That way, gold can only be recovered from wastewater that actually came from a gold process.

This is not part of 2.9.11 yet, but it is the direction I want to follow for future wastewater extensions.