The city will begin allowing private firms to deliver some of the commercial waste they handle to city processing plants and will start distributing the garbage from commercial institutions across the five boroughs so that Brooklyn and the Bronx will no longer have to take most of Manhattan’s commercial waste.

The decision to change the way the city handles garbage produced from offices on Wall Street or restaurants on the Upper West Side is one of a roster of changes that appear in Mayor Bloomberg’s 20-year plan for disposal of solid waste. The proposal will be released next week, the city’s sanitation commissioner, John Doherty, told The New York Sun in an interview yesterday.

“The big issue on commercial wastes is that 40% of the commercial waste produced in the city is from Manhattan but most of it gets disposed of in Brooklyn and Bronx,” Mr. Doherty said. “We’re going to start telling people about how we see the commercial waste of the city being handled, and trying to make it more equitable for the different communities around the city.”

The mayor’s plan envisions a system in which the commercial waste can come into the Department of Sanitation system in the borough in which it is generated, but only if the system can handle it, Mr. Doherty said. The change in distribution won’t happen overnight, he said, and the department plans to work with the city’s businesses to find the most economical way to incorporate the commercial waste.

“The big question is how do you get them to come to your facilities without forcing anybody,” Mr. Doherty said. “You want to ease the tensions in the South Bronx and Brooklyn where all the Manhattan waste goes. You want to get Manhattan to stand up more themselves.”

Commercial waste is just a small component in the mayor’s long-awaited 20-year solid-waste plan, which aims to keep a lid on New York’s garbage costs. Those expenses have been escalating with the scant availability of landfill space and the rising price of transporting it out of state. Mr. Bloomberg’s plan can take effect only if it is eventually passed by the City Council and the state Legislature.

“As we come out with this plan we see it getting more and more expensive to export the waste out of the city,” Mr. Doherty said. “Even with the new plan, I don’t think there will be a reduction in our costs. I think disposing of garbage in the Northeast, particularly in New York City where we have so much of it, will probably go up.”

Instead, the commissioner expects the plan will help stabilize the costs over the long term because of the city’s reliance on long-term contracts as part of its strategy on waste management. The plan is expected to contain, for example, a long-term incineration contract with a plant in New Jersey for Manhattan residential garbage. The contract is similar in scope to the agreement the city made with one of the nation’s largest recycling companies, Hugo Neu, last month.

That Manhattan-based company is investing about $25 million in a plant on the Brooklyn waterfront for recycling of metal, glass, and paper. Right now the city pays around $50 per ton to recycle metal, glass, and plastic. The plant is expected to eventually cut that cost in half.

Mr. Bloomberg is testing new methods to get rid of the city’s waste. One way he is doing that, Mr. Doherty said, is signing long-term contracts, such as the 20-year pact negotiated with Hugo Neu. That contract will probably be signed by the beginning of next year, Mr. Doherty said.

The third piece of the puzzle, Mr. Doherty said, will be the city’s network of eight marine transfer stations, or MTS, which are collecting places for garbage before it goes to a landfill or a recycling center. An early draft of the plan had the city opting not to open the MTS on East 91st Street and another in Harlem. The West 59th Street MTS would be set aside for commercial waste. Typically, neighborhoods resist the facilities because of the truck traffic they bring and the fear of accompanying odors, pests, and noise.

Council Member Michael McMahon, a Democrat of Staten Island who is chairman of the council’s waste management committee, said the decision to include commercial waste in the city’s plan was a sound one.

“Making the transfer station on 59th Street dedicated to commercial waste is a good idea,” he told the Sun. “That is something we have been urging them to do for some time.”

There are also plans for the resurrection of the marine transfer station on the Gansevoort Peninsula in Brooklyn, which would make it possible to ship recyclable waste by barge to the Hugo Neu processing center in Sunset Park.

“We’ve had meetings with community board,” Mr. Doherty said. “The point down there is the city wants to open up an environmental center as well as a transfer station. That would be the ideal spot to export paper and glass and plastic out. That way Manhattan can deliver their recyclables to Hugo Neu in Brooklyn. But that has a ways to go, too. There will also be a park down there. That is being looked at.”

Mr. Doherty declined to give the precise mix of MTS and private stations. Whatever the city chooses, he said, it is bound spark criticism. “When the solid waste management plan comes out and says we’re going to use this MTS and we’re going to use this MTS, there is going to be people who say great and some people say why come to my neighborhood,” he said. “So there is going to be that give-and-take. And there will be some give-and-take by the time the plan is finally adopted by the City Council.”