By Jon Hurdle

WILMINGTON, Del. Jan 13

On a windswept industrial site near the Port of Wilmington, a front-end loader tips a fetid mass of half-rotted food and plastic bags onto a 20-foot heap inside a large blue shed.

It's the start of a process that will turn thousands of tons of rotting food, yard waste and paper products into rich compost that will be used to help farmers grow crops and homeowners nurture their shrubs.

The compost also reduces the volume of landfill waste, saves waste-disposal fees, cuts emissions of climate-changing methane, generates carbon credits for businesses, and returns soil nutrients to their source of origin.

Composting, long valued by gardeners, is just beginning to be adopted on the industrial scale exemplified by the Wilmington Organic Recycling Center, which claims to be the biggest of its kind on the East Coast of the United States.

The $20 million center opened in November and aims to produce 100,000 tons of compost annually when it becomes fully operational in April. The compost will be derived from 160,000 tons of waste that will be diverted from bulging landfills.

Institutions such as schools, stores, supermarkets, and hospitals will pay less to compost their waste than to throw it in a landfill.

The center, built on a 27-acre brown-field site, charges clients $50 a ton to dump their waste at the compost plant, less than the state-wide rate of $61 a ton to dump waste in one of the three landfills in the state, said Scott Woods, chief executive of Peninsula Compost Group, which manages the facility.

"We are providing optimal conditions for backyard composting," said Woods.

The waste is sorted to remove large, non-degradable material, and then transferred to about a dozen long heaps where the natural rotting process, aided by special aeration and periodic turning, converts it into compost in eight weeks.

Inside the massive heaps, the temperature will rise to 160 degrees Fahrenheit (71 degrees Celsius) within a few days, killing off any fecal coloform, salmonella and weed seeds. Green GORE-TEX tarps allow each heap to breathe while helping to generate heat and shielding them from rain.

Computers monitor the temperature and oxygen content of each heap with data gathered by stainless-steel probes inserted into the rotting material.

Rising landfill fees and a growing public demand for a greener lifestyle have made composting commercially viable, according to Nelson Widell, a Peninsula partner.

"You need to be in an area where the tipping fees are high enough," he said.

Wawa, a convenience-store chain that delivers about six tons of mostly coffee grounds a month from two pilot stores, is saving $300 a month by reducing its landfill fees, said Judy Ward, chief executive of Advanced Enviro Systems, which helps Wawa and others businesses go green.

The composting of food waste has boosted Wawa's recycling to 48 percent from 20 percent of the waste stream, Ward said.

She added that the financial benefits of composting may be reduced by increased transportation costs to the new center, or by investment in new containers for the spoiled food.

While there is a growing business demand for sustainability, the financial benefits of composting underpin the new center, said Woods.

"The economic model works because it's effective and simple," he said.

-Reuters