Researchers take the stink out of pig manure

US researchers said they have found a way to take away some of the stink of pig manure: bombard it with a little ultrasound.

David Soll, a biological sciences professor at the University of Iowa, has applied for a patent on ultrasound technology that cuts in half the build-up of hydrogen sulphide, a key odour-producing ingredient.

Scientists, pig farmers and pork industry officials said the technology could be a cheap, environmentally safe approach to deal with a major complaint against factory farms.

And they said the technology may also be effective in treating waste from dairy and beef cattle and poultry operations.