Yard Waste Serves Up Prime Compost, Just Hold the Plastic

In my last column, I encouraged you to using red wiggler worms. Recycling yard waste, like leaves and grass clippings, on the other hand, is one thing that Pierce County Solid Waste and Recycling has down to a science. The transfer station in Purdy is a state of the art facility that makes top quality organic compost out of your yard waste.

We’re lucky to have a finely tuned composting operation right in our back yard, and making the extra effort to keep your yard waste out of the trash could mean 40 percent less stuff going to the landfill and a valuable end product.

If you live in Pierce County and have garbage pick up, you can request a yard waste bin as well. Also, any resident can bring their yard waste to a transfer station for no cost.

Rusty Cole, Operations Assistant Manager of Pierce County Solid Waste and Recycling, explained the whole process to me, including his biggest nemesis: “biodegradable” plastics.

At the transfer station, the organic material is run through a grinder and then spread in long piles called windrows to decompose. As they break down, the piles reach temperatures of over 150 degrees, hot enough to kill weed seeds, E. coli and salmonella.

The piles are monitored closely to keep them at the right moisture and temperature levels, so that the compost is fully decomposed and offers a good ratio of carbon and nitrogen for plants. 

Once it is stable, the final product is screened to make three different products: fine compost soil amendment, coarse compost-mulch and very coarse “hog fuel”. In Gig Harbor, fine and coarse compost products that meet the same safety standards for certified organic farms is available for sale at Purdy Topsoil LLC.

The hog fuel is the stuff that is too coarse to break down quickly, but it is used at county landfills as a daily cover that continues to decompose between layers of garbage. The whole process, from initial grinding to finished product, takes just about 38 days.

So what is Cole’s biggest problem with foreign materials in yard waste? The new generation of bags, plates and utensils marketed as “biodegradable.” Sure, these products are made from plant-based materials that will eventually decompose, but some may take up to 3,000 days.

In the 38-day cycle at the Purdy transfer station, the only thing they contribute to the composting process is grinder-clogging, turner-obstructing plastic bits that add to the cost in terms of staff and equipment time.

Cole suggests that using a reusable container like a heavy duty plastic garbage bags for leaf collection is the best option. And that is a good reminder that the saying “Reduce, Reuse, Recycle” is indeed written in order of priority.