Aside from the difficulty of persuading residents and businesses to divide their trash, many towns and municipalities have been unwilling to make the significant capital investments in machines like composters that can process food and yard waste. Yet attitudes are shifting, and cities like San Francisco and Seattle are at the forefront of the changeover. Both of those cities have adopted plans for a shift to zero-waste practices and are collecting organic waste curbside in residential areas for composting.

Food waste, which the E.P.A. says accounts for about 13 percent of total trash nationally  and much more when recyclables are factored out of the total  is viewed as the next big frontier.

When apple cores, stale bread and last week’s leftovers go to landfills, they do not return the nutrients they pulled from the soil while growing. What is more, when sealed in landfills without oxygen, organic materials release methane, a potent heat-trapping gas, as they decompose. If composted, however, the food can be broken down and returned to the earth as a nonchemical fertilizer with no methane by-product.

Green Foodservice Alliance, a division of the Georgia Restaurant Association, has been adding restaurants throughout Atlanta and its suburbs to its so-called zero-waste zones. And companies are springing up to meet the growth in demand from restaurants for recycling and compost haulers.

Steve Simon, a partner in Fifth Group, a company that owns Ecco and four other restaurants in the Atlanta area, said that the hardest part of participating in the alliance’s zero-waste-zone program was not training his staff but finding reliable haulers.

“There are now two in town, and neither is a year old, so it is a very tentative situation,” Mr. Simon said.

Still, he said he had little doubt that the hauling sector would grow and that all five of the restaurants would eventually be waste-free.