The time is near, Cornell University waste-management researchers say, when patrons of environmentally friendly restaurants can take home two packages: the traditional doggie bag of leftovers for tomorrow's lunch box plus a sack of compost for the garden or window box. And if the patrons had visited the restaurant two months before, there is a chance tonight's pleasantly earthy-smelling package would contain microbially processed food scraps from their previous meal. Technology for food-scrap composting has matured to the point, Cornell experts say, where small family restaurants, 70,000-inmate prison systems and all food servers in between can practice on-site composting -- without offending delicate sensibilities.

"Food-scrap composting has presented challenges. There's no doubt about that," said Thomas L. Richard, a biological engineer in Cornell's College of Agriculture and Life Science. "But research at the Cornell Department of Agricultural and Biological Engineering and elsewhere has shown how to compost just about any kind of food waste, efficiently and inoffensively."

The latest technologies, as well as advice on setting up on-site compost facilities, trouble shooting and marketing the final product, will be presented by Richard and researchers in the Cornell Waste Management Institute at a Food Scrap Composting Workshop, Oct. 23-24, at the Sheraton University Hotel in Syracuse. Co-sponsored by Empire State Development and the New York State Association for Reduction, Reuse and Recycling, the workshop for managers of food-serving establishments and organizations follows the 8th Annual Recycling Conference, Oct. 22-23, at the same location.

For the workshop, the Cornell institute has prepared a manual with a title that is also the motto of their food-scrap program: "Compost . . . because a rind is a terrible thing to waste!"

Some food-scrap composting systems are as simple and passive as piles of food mixed with bulking materials such as wood chips, according to Richard. The slow process of composting can be speeded up by mechanical aeration, in which machines turn piles of waste or blowers introduce air to accelerate the decomposition. Open composting facilities take up space and don't always make the best neighbors, Richard noted, so the state-of-the-art in an increasingly crowded world are the high-intensity, in-vessel systems.

"In-vessel systems can be monsters, as big as 180 feet long, or they can be the size of a Dumpster and sit next to other trash containers in the alleyway behind the restaurant," Richard noted. Restaurant owners have the choice of keeping the vessels on-site for the approximately two months required for finished compost or they can have the vessels periodically hauled away and replaced by empty ones.

Now reaching the marketplace, some of the more sophisticated in-vessel composters include computerized aeration systems for moisture and temperature control, and built-in record-keeping, mixing, loading and screening equipment. Cornell Professor of Food Science Joe Regenstein is conducting a comparison test of several brands of in-vessel composters, in cooperation with New York City restaurants.

Richard, along with Cornell Professor of Agricultural and Biological Engineering Larry P. Walker and Professor of Civil and Environmental Engineering James M. Gossett, are just completing a three-year study that pushed food-scrap composting beyond "ideal conditions" to the limit, deliberately trying to make a stinky mess.

"Don't try this at home with your backyard composter," Richard said, "but with the right equipment and proper management, even fatty foods can be composted. A whole chicken, a side of beef -- compost microorganisms eat anything we can."

Food-scrap composting experiments at Cornell are conducted in two-story tall vessels where researchers continuously monitor gas levels, moisture, temperature and other key factors. There is plenty of food waste available from dining halls at the 18,000-student university. But for the sake of science, the researchers use something that nutritionally mimics the average composition of college fare -- dog food. Mixed with wood chips to provide carbon and watered for moisture, the fat-laden dog food gives the scientists a compost so rich and black it would make an organic gardener green with envy.

With enough oxygen, composting can handle any odor problem, Richard observed. But without enough oxygen, anaerobic microorganisms take over the composting task. "Anaerobes are slow-growing organisms, and they take a week or two to produce odor, but once they develop a population, they're extremely hard to shut off. If a system goes anaerobic, we recommend that it not be disturbed. Anaerobic bacteria do a good job of decomposing. They just have a PR problem."

One place where food composting, done right, is getting a good name is New York's state prison system. With technical assistance from the Cornell Waste Management Institute, Resource Management Director James I. Marion of the New York State Department of Correctional Services oversees a food-scrap composting operation that diverts 9,600 tons of organic material a year from the waste stream. Some of the prison food compost is used to enrich soil at the prison farms or in landscaping around prisons, while tons more are donated to schools, libraries and municipal buildings where the compost is applied by inmate work details.

Recycling food from 69 corrections facilities makes the New York operation the largest single food-scrap composting operation in the United States and probably in the world, reported Marion, a Cornell Cooperative Extension agent in Sullivan County before joining the 69,473-inmate system.

New York's prisoners are more frugal than most Americans, Marion noted, producing, on average, only about one pound of food waste per inmate a day. "And that's not one pound off the plates," he emphasized. "Our food isn't that bad. The average counts food-preparation waste, such as vegetable peelings and coffee grounds. Waste disposal is costly, so everything we can handle in-house will save the taxpayers money," he said, estimating the avoided-cost of disposal for the prisons at $129 a ton.

Other Waste Management Institute research has helped develop composting systems for municipal-level collections of yard waste, commercial and recreational fishing, cattle bedding and sewage plant sludge. One nearby educational institution, Ithaca College, already is composting dining hall food scraps, Richard reported. And Cornell is ready to expand the pilot-level studies by exploring a countywide composting operation that would combine some 700 tons of waste per year from the university's dining halls with scraps from schools and other sources.