More than 250 million gallons of raw wastewater rushes down sewers every day across the Twin Cities. There, it flows with all the liquid waste and by-products from breweries, dairies and other industries into one of a number of treatment plants. Then it literally hits the fan.

Giant fans, more precisely, that require enormous amounts of energy to continuously pump oxygen into the wastewater. For decades, these fans and this aeration process has made wastewater plants the biggest energy consumer in local government.

The city of St. Cloud and researchers at the University of Minnesota believe they're close to finding far more efficient ways to treat waste. One of the answers, they say, comes from the human stomach.