The Public Works Department for the city of Bellingham, Washington found a unique way to take care of the 400 toilets collected as waste from a low-income house project that was being renovated. Rather than sending these no longer usable or functioning toilets to be landfilled, Freeman Anthony, the public works department project engineer, came up with the innovative idea to grind the porcelain down to aggregate that could be used as pavement. The final mixture was made up of about 20% crushed porcelain, diverting five tons of material from landfill. The porcelain aggregate was mixed with concrete and virgin aggregate and used to pave a 2,100 square foot area of sidewalk in the city’s downtown Meador Kansas Ellis Trail Project. The remainder of the six-block sidewalk was paved with concrete made using 80 tons of recycled concrete.
The porcelain toilets were crushed down to aggregate by local companies Bellingham Housing Authority, Dawson Construction, and Cowden Sand and Gravel using a grinder as a size-reduction machine. Crushing the toilets cost the city around the same amount as using virgin aggregate from gravel pits would have and saved valuable natural resources and landfill space.
Grinders use abrasion and compression to pulverize materials to a reduced size, using a series of wheels, drums and plates to process the material. In this case, the toilets were passed through a wide feed hopper, falling into the grinding chamber. Often, grinders use a hammermill in the grinding chamber to process the material. In this case, the grinding chamber contains a rotating hammer rotor with swinging hammers that crush the material and drives it through a screen, thus using impact grinding to reduce it to small pieces. Some grinders come equipped with a grapple for easy loading, if not some form of loader is often used in the recycling process to transfer the material from the fill pile into the grinder. Grinders are available in high or low speed models.
After the porcelain was ground down to a small enough size, it was mixed with fresh concrete and experimented with until producers reached the right aggregate to concrete ratio for the pavement mix. The project earned the city a Silver Certification from the Greenroads Foundation, a nonprofit organization that recognizes sustainable roadway projects and promotes education for sustainable transportation infrastructure. Finding alternatives to landfilling is a common practice in the city that’s roads are paved with 30% recycled material. In addition, Bellingham currently has 12 projects in the works that are pursuing Greenroads certification. “In general, the response was people were stoked. They thought it was cool,” Anthony said, according to Waste & Recycling News. “The local community is pretty into sustainability and all of that here in Bellingham.”