Researchers Develop 'Simple, Scalable' Machine To Clean Water

Engineering researchers at the University of Arkansas (UA) announced on Feb. 14 they have developed a "simple, scalable" machine that can help clean drinking water more effectively and efficiently than conventional systems. The machine, the Supersaturated Dissolved Oxygen or Ozone Injector, shoots a stream of water saturated with either gas directly into a body of water so that harmful substances may be removed before people drink the water.

"Our system simply mixes water with water instead of mixing gases with water," said Scott Osborn, UA assistant professor of biological and agricultural engineering. "Existing systems inject gas bubbles directly into the water, which requires excess time and energy to dissolve the gas into liquid. With our system, it's similar to what happens when you mix coffee with liquid creamer instead of powder. With liquid, you stir it once and it's mixed. With powder, because you're trying to dissolve a solid into water, you have to stir and stir to get it mixed in."

Osborn and his colleague Marty Matlock, associate professor of biological and agricultural engineering, conceived the idea for their invention many years ago after examining conventional systems that introduce gases directly to water. While effective, these systems are inefficient because oxygen bubbles rise rapidly in columns of water and escape into the atmosphere, the researchers said. Gas cannot escape from the carrier stream produced by Osborn's and Matlock's system, so the invention, which is patent-pending, reduces energy expenses because operators do not have to churn the larger body of water to mix gas in water.

Oxygen and ozone are two of the most powerful tools to remove harmful substances from water, the researchers said. Oxygen allows bacteria to consume organic wastes through a process called bioremediation. Ozone kills harmful bacteria and breaks down harmful chemicals for treatment of drinking water without creating harmful byproducts that a chemical like chlorine generates.

Oxygen and ozone must be dissolved in water to be effective. If sufficient oxygen is not dissolved, bioremediation processes in the water become anaerobic, which results in foul odors and slow processing of waste. If ozone is not properly dissolved, it cannot properly treat drinking water. Also, excess gaseous ozone in the air is harmful to humans.

The invention by Osborn and Matlock contains pumps, hoses and a gas chamber. It collects a sample of water from a treatment tank, creek, pond or lake that needs to be treated with dissolved oxygen or ozone. The water is directed through pumps and then into a chamber where the gas is introduced. A liquid solution of water and dissolved gas then comes out of the chamber.

The device can be used for ecosystem restoration, supplemental oxygen for wastewater, aquaculture, lagoon odor control and temporary supplemental oxygenation during times of high demand or construction when other equipment is off-line. Tests of a prototype of the device showed significant cost savings over conventional methods for adding oxygen and air to wastewater during treatment.

Osborn said the system can strategically inject supersaturated water at any depth without significantly disturbing a water column. In other words, with long hoses, the device can pump oxygen into the bottom of lakes where there is insufficient oxygen during the summer without affecting areas that do not need additional oxygen. This can provide habitat for fish and may allow oxygenation of tailwaters from hydroelectric dams so trout fishing can occur during summer months when tailwaters ordinarily do not have sufficient oxygen to support fish.

Ozone is very effective at reducing chemicals that cause taste and odor problems in drinking water and can reduce the levels of potential carcinogens, the researchers said. Osborn's and Matlock's ozone injector can be used for site- and time-specific purposes such as emergency response and in-line drinking water decontamination. The device can also be used in large-scale drinking-water treatment operations and groundwater remediation. Prototype tests resulted in more efficient use of ozone and a higher concentration of ozone in water compared with conventional systems. The prototype device successfully removed all of the 2-Methylisoborneol (MIB) from lake water samples tested. MIB is responsible for the musty off-flavor in fish and drinking water from lakes.

The device is completely scalable too, according to the researchers. Osborn said systems can be built to fit in cupboards for in-home use. Large, trailer-mounted portable units could deliver 200 gallons of water per minute into streams, rivers, reservoirs and lakes. Or, huge, permanently installed units can be constructed for large streams or municipal wastewater treatment facilities. The smaller systems are portable and, along with a generator, can be taken to remote locations that may not have a source of electricity.

Under exclusive license from the university, BlueInGreen LLC, a start-up company and entrepreneurial partnership between the inventors and Virtual Incubation Co., a Fayetteville-based, technology enterprise development firm, is developing the technology into a commercial product. Osborn is chief technology officer and Matlock is chief scientific officer for the company.

Scott Osborn: http://baeg.uark.edu/faculty/osborn/osborn.html

Marty Matlock: http://baeg.uark.edu/faculty/matlock/matlock.html

This article originally appeared in the 03/01/2006 issue of Environmental Protection.

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