The first invention of water treatment was recorded in 1852. In 1938 the first water refinery was installed in Saudi Arabia, while Iranians had the technology thousands of years ago.
The world's first and oldest water treatment device was built by Iranian scientists in Chogha Zanbil, Khuzestan Province. They used laws of physics and substances such as bitumen and brick and sloping surface - still used in world's water treatment – to treat the waters of Karkheh River 50 km away. Precise calculations and mathematical knowledge used in Chogha Zanbil water refinery have astonished even modern engineers.
Roman Ghirshman, French archeologist and Iran expert, discovered the refinery. Water resources were under the ground at depths of 100 meters; therefore engineers and workers had to bring Karkheh waters to the refinery pool through 50-meter-long canals. The pool was filled with layers of sand, pebbles, and charcoal to refine the water passing through.
Bitumen was used to insulate the whole system so that water did not erode it over a long period of time. Since the region is rich with oil, these substances were well known to engineers of that era.
