That empty soda cup you tossed into a recycling bin at Safeco Field or CenturyLink Field or even at The Boeing Classic in August, in a year or so, will probably be compost.

And it will join what it is picked up curbside at your home to become, yes, compost.

That’s because Cedar Grove Compost, which has a plant off Maple Valley Highway halfway between Issaquah and Maple Valley. It’s in unincorporated King County but has a Maple Valley address, and has partnerships with those venues to recycle, compost or re-use as much as it can of the waste produced there.

For example, The Boeing Classic at TPC Snoqualmie Ridge, is a PGA Champions Tour event which draws tens of thousands of spectators to the golf course during the three-day tournament.

Since partnering with Virginia Mason in 2009, which is involved with the organization of the event, Cedar Grove Compost has changed the way waste is managed, explained Stephen Grose, Cedar Grove’s director of facilities and production.

“They approached us about managing the waste at The Boeing Classic,” Grose said. “At that point, we jumped in head first and said, ‘et us take over ecology altogether.’ They wanted us to recycle anything and everything we could.”

During the first year Cedar Grove partnered with the event, the month-long lead up to the event as well as the week of the tournament, 92 percent of what left the golf course was composted, recycled and reused.

Grose noted that no other PGA event can make that claim.

Wood used during construction before the event is either saved for the following year or goes to the composting plant. All the food waste is collected and brought to the composting plant. Cedar Grove has worked with the food vendors at the event to convert to compostable cups, plates, and other items used to serve customers.

Metal, glass, plastic and aluminum are collected at one of seven sorting stations on the course and sent to a recycling company. It is all sorted a second time to ensure that all the trash has been removed.

In addition, TPC Snoqualmie Ridge is now using some of Cedar Grove’s products at the facility.

“We’re working with them closely on using compost on the golf course so they can be less reliant on chemical fertilizers,” Grose said. “As Washington state becomes more strict on the use of chemical fertilizers … I think people are realizing the benefits of compost as a fertilizer.”

Grose had as many as 30 volunteers helping collect and sort the waste coming from the event.

The work is paying off, Grose said, as now 98 percent of what’s generated at the event is recycled, reused or composted instead of going into a landfill.

“We’re really proud of this,” Grose said. “We’re pleased to support a great cause. We get to partner withe PGA to do something nobody else is doing. To be able to show what we’re doing at a golf course show this can be done at all sporting events … and just don’t accept that there’s not a solution.”

At the plant in Maple Valley which opened in 1989, Grose said, it will process 190,000 tons of material this year along and 80 percent will be yard waste.

All of King County’s green waste along with most of Snohomish County’s goes to Cedar Grove Compost.

In one area of the Cedar Grove facility is a pile of trash from a recent Seattle Mariners game. Under the same roof is a series of machines that sort and grind the material along with two employees. Grose explained that with the machines and two employees a load from a baseball game can be sorted in about two hours. A decade ago it would take four people and 10 hours.

In addition to the golf tournament in August, the composting company partners with the Mariners, Seahawks, and Sounders as well as 200 restaurants throughout King County to deal with waste that can eventually become compost.

Cedar Grove insists that its partners used compostable products in order to work with them, Grose said.

Once the material is sorted, it is ground up and moved to a large mound where it is covered by a large tarp-like product called a Gore Cover, made by Gore-Tex, which is breathable enough to let oxygen in but keep odors out. It is the highest level of technology used in composting, Grose said.

By the time it passes out of that first phase of composting, where it lingers for 15 to 20 days, it passes all of the state’s regulations.

But at Cedar Grove that’s not the end of the line for the waste-turned-compost.

“Compost is like wine,” Grose said. “It sounds funny, but, the more you age it, the richer and better it is.”

This facility in Maple Valley employs 52, which is the largest employer in the zip code after the grocery stores and Tahoma School District, explained Community Outreach Director Karen Dawson, who is also a Maple Valley resident.

What’s produced there is an alternative to chemical fertilizers, and with the state’s ban of the use of phosphates coming in 2013 in some of those products, the compost is just the kind of product organizations are looking for, Grose said. While it may not work as quickly as some products found at the home improvement store, he said, what others do in two to three days with chemicals it can do in two to three weeks without.

Lawns will look better, be balanced while the use of compost as a fertilizer can also create better water retention, better root structure, Grose said, thus creating a sustainable loop.

Cedar Grove sells five different products and bagged 590,000 thousand units last year, Grose said. Bulk purchases are 90 percent of sales to organizations such as the Washington state Department of Transportation as well as to homeowners.

“Where there’s an opportunity to put this into compost and not into a land fill, we take it,” Grose said.

That yard waste, those empty soda cups from the Mariners game, that food tray from the Boeing Classic, all end up at Cedar Grove Compost and a year from now could be used to fertilize a lawn.