Composting equipment is typically not readily available in sizes that community sites can use. This is true for turning and mixing systems as well as compost trommel screeners and sifters. “Necessity is the mother of invention.” In this age of open-source collaboration, it is encouraging to note that there is an entire online community of folks in various countries sharing trommel screen designs. The same basic rotating cylinder design is available in different configurations: manual turning, bicycle powered, motorized, and solar powered. Many utilize repurposed materials such as bike wheel rims. Users share their YouTube videos, modify each other’s designs, then come back to post their improved versions.
Do It Yourself Trommel is a step-by-step guide by Bruno Navarro of Nexus Bau to building an electric trommel compost screener intended for use at community gardens, schools, urban farms, and other community venues. ILSR supported Bruno in documenting his design in this guide. This screener design is not a new design but rather modifies a common design to incorporate a metal frame rather than a wooden one. In general, metal is stronger and less prone to cracking and rot than wood. To build it, knowledge in welding, electronics, hand tools, and common sense is needed. Find one or more individuals in your community versed in the areas you might not have training or expertise in.
This design was first built and installed at BK ROT, a youth-engaged community composting operation in the Bushwick neighborhood of Brooklyn, New York. By increasing the site’s capacity to screen compost, BK ROT was able to double the radius of clients it served. Bruno also partnered with the Lower East Side Ecology Center to build the trommel screener at East NY Farms over two weekends (2 hours each day), collaborating with the community and staff. It’s also been replicated at GoodLife Garden and two other New York City sites. In New York City, materials and labor are expensive and might run ~$5,000. The design can be scaled up and tailored to different needs.
Watch Youtube instructions: NexusBau – Making A Compost Trommel (15 min.) or download the PDF instructions.
About Bruno Narravo
Bruno is a freelance woodworker, designer, inventor, and video producer. He graduated from The Cooper Union in 2008 with a B.S. Architecture degree. In 2010, he formed a design/build company called “NexusBAU” in Bedford Stuyvesant, Brooklyn, that focuses on unique and singular custom works. Since then he has worked not only with private clients but nonprofit organizations, community gardens, and The New York City Department of Parks & Recreation. He has also taught “How To” classes to individuals who have been marginalized in our society.
All photo credit: BK ROT Instagram
