The city is considering several changes to its recycling operations ?some that have worked elsewhere ?in hopes of invigorating its program.

The first step will be hiring someone to coordinate a marketing effort aimed at encouraging people not to trash their papers, plastics and cans, said Elena Marks, the mayor's environmental and health policy coordinator. Fewer than 20 percent of 160,000 homes in neighborhoods that have the program participate, she estimates.

Such an effort helps San Diego, which spends $500,000 annually for recycling education and sends out fliers in Spanish and Vietnamese, officials there said. Houston stopped funding its education program years ago, and recycling has declined.

The city also is studying fundamental changes that other cities have incorporated.

Marks said the city could someday explore switching to a method known in the industry as "pay as you throw." Some cities charge more for a larger trash receptacle, but they still keep recycling free. That can create an incentive to reduce volume in the receptacle by separating out the recyclables. Fort Worth uses that approach.

"Yes, people want to do what's right for the environment," said Ellen Schmitz, a public education specialist with Fort Worth's Environmental Management department. "More and more these days, people want to do what's right for their wallets."

Houston also could switch to "single-stream" trucks, like those in green-friendly Seattle. There, recyclables are dumped into trucks from one larger rolling container ?much like a regular trash bins here ?making the process simpler for residents and easier for workers. But it must be sorted at a central facility.

The city also might mandate that yard waste be placed in biodegradable bags so workers don't have to slice open each bag manually. And plans are in the works to offer rewards for those neighborhoods with the highest participation rates.

"We have a program that has not reached its potential," Marks said. "We can reinvigorate the program."