Massive stacks of recycled trash inside Alpine Waste and Recycling towered behind Denver City Councilwoman Kendra Black as she posed a question nearly every coffee drinker has asked: What are we supposed to do with those paper cups?

Denver now has answer.

They can be recycled, the city announced Friday.

Friday’s announcement marked the first time since 2012, when milk cartons came aboard, that the city added a new recyclable product to its list, Charlotte Pitt, manager of Denver’s solid waste management, said.

Coffee cups became a hot issue when environmentalists installed tracking devices that showed paper cups were travelling from Starbucks recycling bins to the landfill. In fairness to Starbucks, signs on the bins said that paper cups couldn’t be recycled.

A poly-coated liner inside the cup, a material that keeps the coffee from breaking through the paper and splashing onto your lap, could not be recycled. To solve this problem, the city partnered with the Wisconsin-based company Sustana, which has the technology to strip the poly-coated lining so the rest of cup can be recycled.

It’s all part of a closed-loop system: Recycling enters the Alpine Waste and Recycling plant. It is then sent to Sustana, where the cups are smashed into a pulp before being shipped to paper mills for use around the country.

“The economic impact is huge,” said Mark Bond, sales manager for Sustana, said. “If you just throw something away, that’s one job. But if you recycle, that could be about 10 jobs.”

While recycling coffee cups will spare landfills, other utensils associated with on-the-go coffee still are headed to trash bins. Straws, sleeves, stirrers or anything else that comes with the coffee cannot be recycled.

Starbucks has promised $10 million toward developing a cup that can be recycled or composted. However, the company has not said whether it will take advantage of the new recycling option in Denver. The city doesn’t offer commercial recycling services, but its contractor Alpine Waste does.

Friday’s announcement is a step toward increasing Denver’s below-average recycling rate, and part of Mayor Michael Hancock’s 2020 Sustainability Goals — which include improvement targets on everything from water quality and greenhouse gasses to housing and recycling.

The city currently recycles 22 percent of its waste, Charlotte Pitt, manager of Denver’s solid waste management, said. The goal is to reach, and then exceed, the national average of 34 percent.

“From a recycling rate perspective, we have a lot of work to do,” Pitt said. “But we’re chipping away at it, one small piece at a time.”

The coffee cups make up only about 0.2 percent of Denver’s residential recycling stream, according to the city’s recycling contract.

A theme at Friday’s news conference centered on public education about what can and cannot be recycled. The council has allocated more money in next year’s budget for Pitt and her team to get the message out there, Black said.

“If you bag your recyclables, they’re just going to get brought to the landfill,” Black said. “Don’t do that!”

The city still faces challenges as it improves its recycling program.

Recycling is free, but voluntary. Residents must request bins. And they pay the same trash fee so there is little financial incentive to recycle. The city also doesn’t collect from apartments, condos and businesses.