Researchers from the University of Portsmouth have determined that highly processed building waste can potentially be used to grow tomatoes.

According to the researchers, waste from construction, demolition and excavation (CD&E) is typically processed via a cylinder drum called a trommel, which separates waste material by size. The material leftover and too small for recycling is called trommel fines, and it is this material that the researchers mixed with compost.

Generation and sampling of trommel fines from CD&E Waste. Source: Construction and Building Materials (2023). DOI: 10.1016/j.conbuildmat.2023.130579

"Trommel fines are less than 10 mm in size and consist of small particles of inert and organic materials including soil, crushed rock or concrete, glass, metals, plastics, wood and insulation materials. Currently, there are no markets for this material and it is destined for landfill. But what we've found is that there is potential for trommel fines to be repurposed to benefit various industries, such as horticulture and agriculture," the researchers explained.

The researchers mixed compost with 20% trommel fines and determined that the mixture provided sufficient nutrients for plant growth. The team also determined that the trommel fines could be incorporated into soil composition for the manufacture of Earth-based construction materials.

An article detailing the findings, "An investigation into the uses of trommel fines produced from recycling of construction and demolition waste", appears in the journal Construction and Building Materials.