The Many Faces of Water
Water performs many essential functions in industrial processes, including evaporative cooling. At the same time, water is a limited resource, and as the cost of water rises, its role evolves. In water-scarce regions, evaporative cooling has given way to dry cooling and adiabatic cooling — methods that reduce the cooling systems’ water demands.
Of course, industrial cooling is not the only function that water serves during manufacturing processes. Water is an excellent heat transfer medium but it serves equally well as media for cleaning, processing or transport. I was reminded of water’s versatility when I read about two research projects.
The first, conducted by a team at Penn State, studied the effectiveness of using electrolyzed oxidizing (EO) water in place of the chemicals typically used in alkaline and acid washes at dairies. Typically, many farms use clean-in-place (CIP) methods for cleaning the pipes that transport the unpasteurized milk after it leaves the cow. The researchers replaced the first three stages of the CIP process — warm water rinse, alkaline wash and acid rinse — with electrolyzed oxidizing water rinses. Using EO water was just as effective as the chemicals traditionally used, says Ali Demirci, a professor of agricultural and biological engineering at Penn State.
To produce EO, an electrical current is passed though tap water combined with table salt. During electrolysis, the electrical current breaks the water and salt into smaller components and produces acid water and alkaline water. (Learn more at http://bit.ly/1RYvSw4.)
Elsewhere, researchers at the University of Florida tackled water-intensive mineral processing in search of ways to release locked up water resources. The team notes that cleaning up water left over from mining operations — where it is used for mineral processing, dust suppression and slurry transport — takes 25 to 50 years on average. This is because the spent water holds particles of electrically charged mineral byproducts that, because of their charge, remain suspended in the water instead of sticking together and settling in the bottom of the massive settling ponds used for dewatering.
Mark Orazem, a distinguished professor of chemical engineering in UF’s Herbert Wertheim College of Engineering, developed a separation system that uses electrical fields to force the charged particles to form a sludge cake. That which occurs naturally over decades happens in hours instead. Though still in laboratory-scale prototype, Orazem’s team is working to scale up the phosphate mining technology.