The water treatment plant was one of the biggest technological achievement ever made.
While water pipes were already in use, there was no way to clean dirty water and as such it just got redirected into oceans, rivers and lakes.
This caused a great natural disturbance and lead to the death of many people, animals and plants.
A change was long overdue as a scientist from the newly build, and back then pretty small, Mensus
had a flash of genious.
through the use of SC - Samantel
he was able to connect a large amount of Water Saxum
with each other.
After he was done with his prototype he had build a high cylinder which connected directly to the water pipe system of the city.
Talented Water-Wielders were recruited to test it.
By having the ring of saxum connect to a floor entirely made of Samantel, it was possible for the water wielders to use their signum without being near the crystals. The only constriction was for them to be barefoot.
Now they used their Signum to raise the water into the giant cylinder and part it from the dirt. The dirt got disposed int large containers at the edge of each cylinder.
Through the need of clean water and self sufficient cities the water treatment plant arose.