Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sound cleans up water purification

16.05.2002


High-energy bubbles scour municipal water filters.

Sound waves could provide a greener way to make tap water taste better.

Ultrasound can make bubbles in water that could clean ceramic filters quickly and cheaply, say Linda Weavers and colleagues of Ohio State University, Columbus1. When the bubbles burst, they release energy that makes tiny, but fiercely powerful, jets of water that scour the filter’s surface and flush away debris.



Most municipal water treatment relies on slow, environmentally risky, chemical purification. A greener, more efficient alternative is to use membrane filters. These have pores so minuscule that they sieve out particles and microorganisms as small as viruses; but they get clogged easily. Fouled filters must be removed and either scrubbed or replaced, slowing the process and raising its cost.

Ultrasound cleaning could make membrane filtration the rule rather than the exception, hopes the Ohio team. "If you left the ultrasound running you could clean the filter while it is still in use, and keep it from ever getting clogged in the first place," says Weavers, who believes that, scaled up, the process could replace chemical water purification.

Philip Brandhuber of McGuire Environmental Consultants in Denver, Colorado, who specializes in membrane filtration of drinking water, agrees, saying he is pleased to see this "completely new approach to the fouling problem".

One potential problem is that the bursting bubbles could damage the filters. Ceramic filters are hard-wearing and heat resistant. But ultrasound cleaning could degrade the cheaper polymer membranes that are more widely used, points out Menachem Elimelech an environmental engineer at Yale University.

Others think that the benefits of a switch to ceramic filters would justify the costs. Tom Allsop, Water Department superintendent for Pinesdale, Montana - whose plants currently use sand and paper filters - says he’d jump at the chance to install an ultrasound-ceramic combination. "If it works as well as they claim, it would save us enormous amounts of money each year," says Allsop.

Brandhuber doubts that Allsop’s enthusiasm is representative of the drinking-water industry as a whole. The industry is inherently conservative, Brandhuber says, being concerned with public health and publicly funded. Before municipal plants are likely to invest, the technology must undergo much more rigorous investigation, he adds.

Weavers’ group intends to do just that. They are planning more tests to determine how well bubbles remove different contaminants and how different types of filter withstand the sound-induced scouring.


References
Chen, D., Weavers, L. K. & Walker, H. W. Using ultrasound to reduce ceramic membrane fouling by silica particles. Presented at the 2002 National Meeting of the American Chemical Society, Orlando, USA. (2002).

INGRID HOLMES | © Nature News Service

More articles from Ecology, The Environment and Conservation:

nachricht Listening in: Acoustic monitoring devices detect illegal hunting and logging
14.12.2017 | Gesellschaft für Ökologie e.V.

nachricht How fires are changing the tundra’s face
12.12.2017 | Gesellschaft für Ökologie e.V.

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>