Smaller cities across the country have been doing it for years: forcing residents to buy special garbage bags to set out on their curbs, and then taking the profits from the bags to pay for the municipal trash disposal system.

Now, the chairman of the New York City Council’s sanitation committee wants to adapt the idea —  or another “pay-as-you-throw” system — to the big city in order to give people an incentive to recycle and raise money for better recycling infrastructure.

“There are a lot of people who know that this is the wave of the future,” City Councilman Antonio Reynoso said Wednesday.

Reynoso, who represents Williamsburg, Bushwick and a small part of Queens, said that people would pay only for trash they throw away, not for food scraps that they compost or material that they recycle. He said the city would have to work out some enforcement system to make sure people did not throw trash into recycling bins so they would not have to pay for it.

“What we are saying is that the more you recycle, or the better you are at diverting your trash form this general refuse into recycling, the more you save,” he said.

Reynoso mentioned the idea during a panel on composting sponsored by the New York League of Conservation Voters Education Fund held at New York University’s Robert F. Wagner Graduate School of Public Service. He said that he was just beginning to form a working committee of experts to develop a proposal, and acknowledged that it would be a tough political lift.

But the reception from the crowd of composters, waste specialists and environmentalists was enthusiastic: Numerous members of the audience offered him their business cards during a break in the program and volunteered to help.

Right now, New Yorkers recycle just half of the plastics, paper and metal that the city collects. The rest enters the waste stream.

A deputy sanitation commissioner who happened to be on the same panel, Bridget Anderson, said charging people for trash posed several logistical challenges. Bu she added that they were “not insurmountable” and called the idea “not something we think we should forget about.”

The councilman, whose district sees a lot of traffic from garbage trucks because of waste transfer stations there, predicted that it would be years before a pay-as-you-throw system launched — assuming one would be approved by the City Council and Mayor Bill de Blasio.

One key question would be how residents would pay for disposing of trash. In Gloucester, Mass., for example, residents buy extra-large purple bags for $2 each from ordinary grocery stores, with most of the profits going to fund trash collection. Those bags are the only ones that the trash crews are supposed to pick up from the curb. San Jose, Calif., offers different sizes of trash carts, and residents pay a monthly fee depending on which one they choose to use.

Currently, residential trash collection in New York City is paid for through taxes. Reynoso said the money raised through pay-as-you-go could lead to a tax cut.