Denver is preparing to launch a “pay-as-you-throw” trash collection program, Mayor Michael Hancock announced at an elections forum Thursday, reviving an idea that was discussed his first year in office.

“Within a year, we’ll be moving toward the pay-as-you-throw,” Hancock said at the Alliance Center.

Currently, Denver doesn’t charge residents for the 139,000 tons of trash it collects each year. The new model would charge for trash collection — and the cost would depend on the amount of trash.

Electoral challengers Lisa Calderón, Penfield Tate and Jamie Giellis also endorsed the pay-as-you-throw model. Tate also called for free composting, while Giellis and Calderón said the city should try to incorporate large apartment buildings into its recycling and waste programs.

“We have been moving in this direction for quite some time,” Charlotte Pitt, interim director of solid waste management for Denver, said Friday of the proposal. “We do still have a lot of work to do.”

RELATED: New recycling report trashes some of Colorado’s “green” reputation

The change could improve the city’s recycling rate: Currently, only about 22 percent of the city’s municipal waste stream is recycled, compared with 35 percent for recycling and composting nationally.

How it works

“I think it comes up about every two to three years. It’s always a difficult conversation in Denver,” Pitt said.

The current effort began two years ago. The change isn’t final — it will go through a community input process before an expected decision next year — but city staff members already have laid significant groundwork.

“If the decision is made to absolutely do this, we could roll it out relatively quickly,” Pitt said.

Waste workers probably won’t be weighing your trash cans. Instead, residents might choose between differently sized trash carts. The larger the cart, the higher the price.

Pitt wouldn’t guess at costs, but she shared research on other pay-as-you-throw cities. Customers in Lafayette pay $31 monthly for a 95-gallon cart, while in Fort Collins it’s $34 a month, she said. In Austin, Texas, and Portland, Ore., bills might top $40.

However, those prices are for large carts that can hold eight or nine standard bags of trash. Cities typically offer three or four sizes, with lower prices for smaller carts. Hancock also has asked that the city minimize the effects of the new system on low-income residents.

Meanwhile, Denver is buying 13 new compost trucks and rolling out a marketing campaign to reduce trash output.

If the city does start charging for trash, it would likely base the bills on the cost of service. Denver spends about $25 million a year on trash collection, Pitt said.

At the moment, Denver charges $120 a year for composting — the only waste service that comes with a bill.