I wanted to design a small, family owned dying factory in medieval times, powered by waterwheels. I dont believe anything like this existed and there is very little reference about the trade, so nearly all of what you see is fictional.
The family makes their own red dye from the abundance of berries on their estate, and uses the waterwheels to elevate water into the building through a series of halfpipes, and drain the water back into the river after it has been used for washing fabric.
In medieval times the fabric dyers would soak fabric in giant vats of dye, and constantly stir it with big wooden sticks; I designed a low tech mechanism powered by the same waterwheel to stir the fabric in the vats in a similar fashion as it would have been done manually.
Historically, fabric dyers had a very dangerous job, as their work consisted not only of washing and dying the fabrics, but of making the dyes and inks themselves out of plants and berries - many of which were lethal if handled, inhaled or ingested. Regardless, they were still paid very little.