Special plastic trash carts and changes in how residents are charged for trash service are ideas still very much alive at Lawrence City Hall.

After a Tuesday afternoon study session, a majority of commissioners said they want a new task force that will study such ideas as automated trash trucks that would require the use of special carts and a new billing system that would charge people who regularly throw away lots of trash a higher fee than people who don’t.

Some commissioners even went so far as to predict such changes will be needed to keep the city trash system financially feasible in the future.

“It is important for everybody to realize that the status quo will cost more next year and the year after that because landfill fees are going up, labor costs are going up, health care costs are going up,” City Commissioner Aron Cromwell said. “If people are reluctant to change something because it is going to cost more, well, it already is going to cost more.”

Commissioners also didn’t throw out the idea of allowing a private company to take over the city’s trash service. City commissioner Mike Dever said he wants to eventually have a private party submit a bid on for the city’s trash service, once city leaders determine exactly what they want that service to look like.

“I think we need to know whether we can provide the service on an equal level with a third party,” Dever said.

But first, the city needs to determine what changes it wants to make to the trash system. Commissioners informally agreed Tuesday to create a new task force that will study the issue. A formal proposal for creating the task force — including ideas about who may serve on it — will be brought before commissioners on Feb. 8.

The task force is expected to study at least three key ideas:

• Conversion to more fully-automated trucks. The trucks — some of which have robotic-like arms that pick up trash containers — generally require smaller crew sizes. But the systems often require residents to use special plastic carts and prohibit people from setting out a traditional trash can or sack at the curb.

• Creation of a variable pricing system. Some commissioners have expressed concern that all residential customers are charged a flat monthly rate, regardless of how much trash they throw away. With a system that requires people to use special plastic carts, the city may be able to change that. For example, the city could provide different sizes of carts — usually anywhere from about 35 gallons to 95 gallons — and charge people a different monthly rate based on how large of a cart they have.

• Expansion of curbside recycling operations. The city currently has six private companies that offer curbside service. If the city changes its monthly fee system, some commissioners have said curbside recycling should become a larger part of the equation. That could mean the city would start offering the service to everyone and residents automatically would pay for it as part of their monthly bills.

All of the issues have more questions than answers associated with them right now, City Manager David Corliss said. If the city wants to make a change in the trash system by 2012, many decisions will have to be made before June of this year. Corliss said whatever the commission does will have to include lots of opportunity for public comment.

“I know there are a lot of questions out there,” Corliss said. “I had a lady at a Christmas party stop me from getting a cookie because she wanted me to explain how she was going to get a cart up and down her steep driveway. We can make changes and we can make progress, but we have to bring the community along.”