Festival fans who have bought drinks in biodegradable cups while attending Ottawa shows the last few years might be surprised to learn that those plastics could end up in a landfill.

Vendors at Bluesfest have been selling biodegradable cups for years and this year, Ottawa's Tulip Festival will begin selling water bottles made from the same corn-based plastic, which can be composted and then returned to the earth.

But in Ottawa, there's no municipal composting facility that can handled that type of waste.

Mark Monahan, the executive director of Bluesfest, said he's proud of the festival's environmental record because they've served hundreds of thousands of drinks in biodegradable cups in the last three years.

"Our understanding all along has been that they've been going to a compost facility, not a landfill," Monahan said.

But without a city-owned composting facility, those cups have instead been going to Laflèche Environmental, a waste management company east of Ottawa.

Jeff Laflèche, the firm's business manager, said cups that are brought to his site would have ended in their bioreactor landfill. That type of landfill is more eco-friendly than most, he said, because it traps the methane gas emitted by the garbage and uses it to generate electricity.

But a company that makes the corn-based water bottles said bioplastics can only break down under specific conditions.

Michael Keeffe, the president of +1 Water, based in Montreal, said bioplastics have to be heated to 60 C for two weeks for them to biodegrade. He said he hopes those conditions will be present when the 7,000 bottles he's supplying to Ottawa's Tulip Festival are shipped away for disposal.

"The key ingredient to start the breakdown process is to have that initial heat," he said. "And my understanding of landfills is that it's hard to control [the temperature of] them and that's part of the problem."

Laflèche said his company is hoping to use their new industrial composting facility to process the cups used at the Tulip Festival, which runs from May 1 to May 18, rather than shipping them to their landfill.

As long as +1 Water's analysis of the bottles' biodegradability is correct, he said, the new composter should allow Ottawa's festivals to continue to be proud of their environmental purchases.