PHOENIX, Arizona – With their black and yellow recognisable colouring, school buses have proven to be a reliable way to transport millions of children to school every day.
Now engineers from the University of Arizona have found a way to turn the trusty school bus into a mobile, solar powered desalination unit.
Partnering with consultancy Apex Applied Technology, the mobile water treatment system was recently delivered to an off-grid school in the water-scarce Navajo community.
The desert portion of the Navajo Nation in northeastern Arizona receives only seven to 11 inches of rain per year. There is, however, plenty of groundwater — it's just high in salinity and contaminated with metals, including uranium, in some areas.
The system draws up water up from wells into a feed tank on the bus, before passing through three filters with progressively lower micron ratings — 10, 5 and 1. Next, the water is forced through a series of semi-permeable membranes.
About 20 percent of the water pulled in from the well will be filtered into drinkable water, and the rest will be returned to the source.
This is the third water purification system to come out of the partnership between the University — including staff, students and alumni from the Department of Chemical and Environmental Engineering — and Apex Applied Technology, or AATech, which advocates for federal funding for underserved populations.
It is the first, however, to be built into a bus.
"It's a way to extend infrastructure to these communities," said Bob Arnold, a UA professor of chemical and environmental engineering and an expert in water purification and wastewater treatment systems.
Vicky Karanikola, a UA professor in chemical and environmental engineering, added: "It can provide water for the Navajo Nation for many, many decades if we treat it."
The bus idea initially came to STAR School co-founder Mark Sorenson a few years ago as the Standing Rock Sioux began pushing back against Dakota Access Pipeline developers to protect the tribe's drinking water and ancestral lands.