“HOT” Bubble Power Goes to Work on Polluted Site in China

Scientists at the University of Utah have developed a new bubble-based technique for cleaning up polluted soil, especially soil contaminated with metals. The new technique may also work on polluted water. Testing is under way at a site at  Lake Taihu in China, which takes in polluted runoff from a heavily industrialized region. The system, called heightened ozonation treatment (HOT), uses pressurized ozone gas microbubbles to break down pollutants.

Ozone and Remediation

HOT has been lab-tested, so this demonstration marks the first time the technology will be tried in real life circumstances.  The key component is the reactor, which produces ozone microbubbles under pressure. In this test, the reactor will take in contaminated soil, which will be subjected to repeated pressurizing and depressurizing. The process creates microbubbles that break down hydrocarbons, and additives are used to precipitate metals and other contaminants out.

Green Remediation

The HOT system represents a sort of middle ground between the old method of remediation, in which contaminated soil was simply dug up and trucked to a landfill, and newer methods in which soil is decontaminated while still in place. In this pilot demonstration, apparently the idea is to take the decontaminated soil off site and use it to plant trees on public lands, though it’s also possible that the system could be used to return the cleansed soil to its original location.

A Step Beyond HOT

In either case, the HOT system does require soil to be excavated. In other new remediation methods under development, the idea is to save time, energy and expense by treating the soil without even excavating it. Some areas under exploration include the use of microorganisms to break down perchlorate. Scientists are also discovering how to use natural additives such as lactate to boost microbial activity. Another green option is to use renewable energy to power pumps and other remediation equipment, as is being done with solar energy at Altus Air Force Base.

Remediation and Green Jobs

The HOT system, if it can be developed commercially, will add another tool to the remediation toolkit, and enable more sites to be cleaned up and reclaimed. Along with other new remediation methods, it dovetails nicely with the EPA’s new Re-Powering American Lands program, which is designed to put abandoned industrial sites back to work as locations for new clean energy installations that create new jobs, so you get the sustainability twofer of reclaiming land and reducing greenhouse gas emissions, too. If you’d like to see federal funding continue for the Re-Power program and other green jobs initiatives, that’s another good reason to participate in the upcoming midterm elections and check your candidate’s position on global warming before you vote.

Ozone and Sustainability

Cleaning up polluted soil or water is just one role that ozone is taking on in the sustainable future. At North Carolina State University, biofuel researchers have found that exposing biomass from woody plants to gaseous ozone can break down the matter in a single process that produces no liquid waste, in contrast to conventional methods that involve multiple steps and produce a copious amount of waste. If developed commercially, the new method could significantly lower the cost of producing biofuel from woody material.

Image: Bubbles by Jeff Kubina on flickr.com.