SRP, researchers work to recycle old wire casings

PHOENIX - It takes a lot to bring electricity into people's home everyday, and that can mean a lot of waste at the landfill.

Now, university researchers are working with Salt River Project (SRP) to devise a new way to use and reuse the miles of cables that lie under our feet.

At a six-acre SRP facility, there are hundreds of eight-foot tall spools, and wrapped around them are hundreds of feet of thick, dense cable that runs underground for SRP.

"Some of the cable might look new, if you look at it, but it’s degraded over time, so it needs to be replaced," said SRP Sustainable Solutions Manager Sam Cutruzzula.

All of it can be re-used, but since the material is built to weather anything, tearing it apart will take massive work.

Firstly, the material is fed into a machine, where it is first chopped into slices. The material is then dumped into a granulator, according to Cutruzzula, where it is continuously ground down.

Then, the material is shaken apart and separated, with copper scraps going into one-to-two ton bins.

"You can see how clean that copper is," said Cutruzzula.

Like copper, aluminum will go through the same process. The metals can be sold or reused, but the plastic casings end up in another bin. However, thanks to a $88,000 research grant to the University of Arizona, the plastic casings are now being recycled and reused in concrete, for the first time.

"Develop sustainable construction materials by recycling different types of waste," said Lianyang Zhang with UArizona.

Officials with SRP say the search for a solution to all the waste has been years in the making.

"Great to see we’re actually making progress," said Cutruzzula. "We feel this is actually going to work well."

Concrete made with a new formula that uses the plastic ware is about to be used in SRP trenches. If it works, the machines will eventually work non-stop, and craft the sidewalks of the future.

"It’s important because if we can continue to recycle this material, it increases our diversion rate and keeps it out of the landfill," said Cutruzzula.

Depending on how long the cable is on one of the spools, it can take about an hour to process them. That means there is already a year of work ahead.