A coffee cup tossed in the trash will either be reduced to ash in a giant fire or spend its days buried underground. So which one is it?

The answer depends on where it was tossed. But assuming it can't be recycled -- about half the Twin Cities' waste is now recycled -- the chance it will end up in a landfill has grown dramatically since the early 1990s, according to state trash data.

While landfilling has been on the decline locally since a peak in 2006, the Twin Cities still sent more than twice as much trash to landfills in 2015 by weight than it did a quarter century ago, data show.

That 774,000 tons weighs more than two Empire State Buildings. After being compacted, that's still about a Metrodome-sized mass of leftover food, product packaging and other garbage entering the ground every two years.

“There’s a lot more landfilling of waste than what people realize,” said Paul Kroening, supervising environmentalist at Hennepin County. “I think people think that we’ve really reduced our landfilling of waste to almost nothing, and that’s not really true.”

State regulators, who are pushing to redirect more waste from landfills to area incinerators, attribute the 1990s rise of landfilling largely to a 1994 U.S. Supreme Court decision that essentially blocked governments from mandating where waste must be hauled. Counties could therefore no longer require trash to be brought to their incinerators.

A subsequent decision in 2007 clarified that governments could require waste to be trucked to publicly operated facilities. Washington and Ramsey counties have since bought a processing plant in Newport with the intent of directing waste there, where metals are removed and the trash is ground up for incineration.

Landfilling has few advocates, but incinerating trash to make energy has also attracted ample controversy over the years due to the air pollution from local burners. The Hennepin Energy Resource Center in downtown Minneapolis is the frequent target of ire from environmental groups.

Yet state law prioritizes burning over landfilling because it produces energy and the processing plants generally remove recyclable metals.

A growing Twin Cities population is another factor for additional landfilling. But trash data maintained by the Minnesota Pollution Control Agency show that the overall tonnage of waste has risen by just 31 percent since the early 1990s, while landfilling has more than doubled. 

Waste Management, the nation's largest trash firm, owns three of the four primary landfills where the metro area sends its trash. Company spokeswoman Julie Ketchum highlighted that there has been a steady decline in landfilling over the last decade. And per capita, Twin Cities residents produce less overall waste than they did in the 1990s.

"We need to celebrate the success we have had in the last ten years instead of looking at a 30-year trend line that fails to reflect advances in waste management methods, new technologies, reduction in the amount of packaging and paper used and less waste generation per capita," Ketchum wrote in an e-mail.

State data illustrate that where you live matters when it comes to where that tossed cup travels. Almost no Carver County trash is burned to make power, for example, compared to about 37 percent of all waste from Hennepin County.

And some counties are doing a much better job than others at recycling. About 34 percent of Carver County’s waste is recycled, a far cry from Scott County’s 51 percent.

Comparing landfilling and incineration to recycling and composting further illustrates differences between the counties. Scott County again emerges a winner. Hennepin County does not report yard waste in its organics category, however, which puts it farther behind other counties.

Despite the proliferation of curbside recycling programs, the tonnage of recycled waste hasn't boomed. But the MPCA says that’s in part because what we recycle is getting lighter, and newsprint is growing rarer as readers shift online.

Peder Sandhei, the MPCA’s principal planner, highlighted the conversion of applesauce containers from glass to plastic, for example. 

“The fact that recycling percentages [are] staying level is a sign that we are actually collecting more material, but it weighs less,” Sandhei wrote in an e-mail. “As the waste composition of household waste continues to evolve, finding acceptable recycling markets will continue to be a growing challenge.”

Ketchum, with Waste Management, said her company advocates moving away from weight-based recycling goals for this reason. A recent state law change states the metro area should aim to recycle or compost 75 percent of its waste by weight by 2030.

“Weight-based goals do not represent the positive impacts on the environment that comes with recycling," Ketchum said. "This is why we need to transition to a measurement system that looks at the environmental benefits of recycling—what materials get the most [greenhouse gas] emissions reduction when recycled?”

There is room for progress, however. The MPCA believes that about 60 percent of the waste heading to area landfills could be recycled. A lot of that is leftover food, which local governments are increasingly trying to steer toward composting.

Overall, the network of public and private entities that handle Minnesota’s waste do it well for relatively low cost, said Tom Halbach, a former University of Minnesota professor and board member of the Minnesota Chapter of the Solid Waste Association of North America. 

Yet there are concerns.

“Within the industry there are people that say, ‘We’re landfilling way too much. There’s valuable stuff – if I could just get the flow to my facility, I could recycle, I could recover x, y, or z. I could get some value,’” Halbach said. “In the landfill, once it’s buried, it’s going to be buried there.”

And all this discussion of municipal waste doesn't even cover the full scope of trash that we generate as a region.

The MPCA is also concerned about the growth of non-municipal waste such as construction, demolition and industrial debris – which now exceeds more traditional household and commercial waste. That includes contaminated soils, sheetrock and other materials.

The agency’s long-term policy plan – due to be finalized in the coming months – attributed some of the growth to municipal waste being reclassified. But it’s unclear precisely what’s driving the spike.

“There’s been a lot of focus on [municipal] waste and not much on non-[municipal],” Sandhei said. “The policy plan is really imploring that we get better data so that we can better understand what’s happening.”

Data Drop is a weekly feature that uses data analysis and visualizations to explain, surprise, inform and entertain readers on topics relevant to Minnesotans. Do you have an idea you'd like us to explore? Contact MaryJo Webster