Feature Article - February 2012
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Greener Grass Awaits

Environmental & Fiscal Responsibility Team Up in Synthetic Turf

By Tammy York


Turf & Infill Removal & Repurposing

"Most of the fields that are eight to 10 years old and in some extreme cases even 12 years old," said Hank Steinbrecher, chair of the Synthetic Turf Association which promotes the use of synthetic turf, "…were made of the polyurethane backing with a monofilament type fiber, and the infill was created from sand and rubber. Right now, there is a growing interest and considerable market opportunity for recycling synthetic turf fields in an environmentally responsible manner."

Polyethylene, nylon, sand, rubber and polyurethane are five extremely different components, and one of the significant problems to recycling the field is overcoming how to separate the components. Since necessity is the mother of invention, there are several types of machines that have recently popped up on the market that cut the field, collect the carpet, and separate the infill from the fiber by using vibration, water, air or a combination of these methods.

Machines on the market for removing infill range in creativity. Some machines literally act as a vacuum cleaner and brush and vacuum the infill out of the fibers. Originally, these machines were developed to rejuvenate the crumb rubber and sand infill, and were not designed to remove all the infill in the field. Therefore the use of these machines typically results in only a 60 to 70 percent reduction of infill in the field.

Other machines on the market remove the infill as the turf is being rolled up from the field. In some cases, the fields are cut into 15-foot wide panels before being processed. The panels are in fed into a machine that rolls the carpet and extracts the infill.

Removal of the infill is important, because companies that grind, melt and recycle polyethylene into another product must have a clean stream of polyethylene. Contaminants such as debris, sand and rubber can dull the grinding blades as well as create a substandard product.

Reclaimed infill can be cleaned and repurposed on a new synthetic field or used to top-dress the outlying natural turf fields once it is tested for metals and lead. For new fields, an alternative to the traditional rubber and sand infill is coconut husk infill. This slow-to-degrade infill can literally be dumped out and composted at end of its lifecycle.

The East Delta Sports Complex in Portland, Ore., was one of the first outdoor installations of a synthetic turf field. It was installed in October 1997 and removed 11 years later.

"Our original intention was to remove the infill and then pull the synthetic turf up free of any infill," said Debra Kneeshaw, lead park technician with the City of Portland Parks and Recreation Department. "However, the infill was basically cemented into the carpet. We had to cut it into sections and shake it out. We collected about 140 yards of infill and then tested it for metals and lead. Once the infill passed the health and environmental tests, it was top-dressed in a thin layer on our natural turf fields." Kneeshaw supervised the replacement and recycling processes of the synthetic sports field.

Old synthetic turf and the infill could be repurposed for batting cages, driving ranges or warm-up areas. The field can also be repurposed by creating something new from the base materials.

"The old way of replacing a synthetic turf field was to cut it up and ship it to a landfill. This cost about $35,000, depending on where you were in the United States," Steinbrecher said. "It doesn't make any sense to tear it out and not recycle it. You're not making any money off of the resource when you could save money by reusing the infill and make money by selling the plastic to a plastic manufacturer or waste-to-energy plant."

The polyethylene is reclaimed by sheering off the fibers from the polyurethane backing. Then the fibers are ground and used in the creation of oil. The plastic is melted under heat to break down the hydrocarbon molecules. Once that is done, the molecules are then in an oil form and can be collected and shipped to a refinery for further processing. This technology is available in several places, but is expected to expand as the market develops and the feasibility for recycling a synthetic turf field back into oil increases.

Both the polyethylene and the polyurethane backing can be ground up and sent to a waste-to-energy plant to be used as fuel for the creation of electricity.