If you are anything like me, once you drop off your household recycling or put it out by the curb, you are done with it. You give it little thought beyond that point and feel your responsibility to the Earth is complete. That describes most of us who bother with recycling at all. However, Alex Stiles doesn’t stop there. This Ph.D. graduate from UT (Energy Science and Engineering and a BS in Mechanical Engineering) is taking it not just one step further but leaps and bounds further. Enter Fourth and Glass Recycling Co., a curbside glass pick-up and recycling program. He isn’t just picking up the glass and taking it to the drop-off for you. His company makes your glass reusable for artists, for landscapers, and for builders.
Several years ago, Knoxville discontinued their curbside glass recycling program. Downtown residents who want to recycle must load empty glass containers and take them to the recycling drop-off center in the Old City (27 Willow Ave.). Around this time (2016), Alex and his family were moving from Chicago to Knoxville for his wife to pursue her career as a Certified Nurse Midwife and for Alex to pursue his doctoral degree at UT. He began considering how to make glass recycling more accessible in Knoxville.
Glass recycling is a cost-prohibitive program due to the sheer physical weight of transporting the product. Unless a city is within 150 miles of a recycling facility, it is unlikely to invest in shipping the glass to a recycling program; instead, the glass goes to a landfill. Knoxville transports its glass to Atlanta, where it is crushed and melted to form new glass products. However, what is sent to Atlanta represents only 7% of glass waste in Knoxville. The other 93% is going to our landfills via resident’s trashcans.
While in his doctoral program, Alex met Dustin Gilmer, who was studying ways to use sand and powder in 3D printing, and Alex was researching 3D printing with UV-curing polymers. Together, they co-founded Vitriform 3D and created a patented-pending 3D method for turning powder from crushed glass into engineered stone building materials. This method uses UV light to cure a special adhesive/polymer to bond the powder into a new material. Think of getting a cavity filled by the dentist and that little UV light they use to cure the filling or the UV light they use at nail salons. It’s the same concept. They also use inkjet heads (like the ones in your home printer) to have the ability to color translucent powders. Since 3D printers work via a computer program, changing the product’s shape, size, or color is as simple as entering a new code into the program. As a local product, they will be less vulnerable to the supply chain issues experienced during the pandemic.
Vitriform 3D has been awarded a $ 1.1 million grant from the Department of Energy and won Knoxville’s Innov865 pitch competition this year, held at the Mill and Mine. Their program will be able to create interior surfaces for homes and exterior cladding that produces less greenhouse gas emissions than traditional building products. Building materials produce 11% of greenhouse emissions. The 3D printed material Vitriform 3D can create has low embodied carbon, is locally sourced, allows for detailed 3D textures and colors, low-cost customization, and has high bending strength. They are getting a robot arm printer that can print 2x4ft tiles with plans for a research and design printer to experiment with 4x8ft tiles. They are currently working out of Alex’s basement and labs at both UT and in Oak Ridge. They aim to build a factory in Knoxville with ten robot arm printers to divert 10,000 tons of glass from landfills and generate over $100 million in annual revenue.
Fourth and Glass Recycling Co. is the next step to achieving those goals. You can sign up for curbside pick-up now. The first neighborhoods served are Fourth and Gill and Sequoyah Hills, but anyone can sign up, and with as few as 12 neighbors, they will come to your neighborhood, too. They have a capacity for 1,000 subscribers. Mandy Tietjen is the Operations Manager and is learning to operate the glass crusher, which sounds kind of fun!
The glass crusher turns the glass into various-sized pebbles, and the powder sifts through. Once separated, the larger pieces are offered to local artists for projects and can be used as mulch as the crusher leaves no sharp edges. The powder goes into what looks like a small sandbox for use in the 3D printing process.
There are different levels of subscription. You can do 1 or 2 bins with either monthly or every other month pick up. They provide the bins. They ask that you rinse the bottles and take off the tops. You do not have to remove labels. If you are interested in the service, get on the waitlist here. Pick-ups will begin in November. They are partnering with Keep Knoxville Beautiful on November 15th, America Recycles Day, to collect glass for recycling. You can see the glass crusher in action and watch your glass turn into sand! Drop in from 3-6 at the UT Recycling Center at 2121 Stephenson Dr. to meet Alex and his team and learn more about this fascinating and innovative program!