Plant converts cow manure into energy

Forty minutes east of South Africa's capital of Pretoria, amid the lowing of thousands of cows and the strong stink of dung, a small factory has taken on the challenge of turning manure into energy.

"Every day, 120 metric tons of manure and 66 tons of recycled paper are mixed in one of these tanks," Bio2Watt project manager Steven Roux said in the shadow of a looming 9,000-cubic-meter vat.

Also in the tank alongside the bacteria-rich dung is a steaming mix of old yogurt, fruit juice and abattoir waste, which bubbles away at 52 C for 22 days.