Wastewater Grit May Find Use in "Green" Pothole Filler
Phoenix666 writes:
Wastewater grit may find use in "green" pothole filler:
Currently, potholes are filled with asphalt. Unfortunately, though, that material contains toxic substances known as polycyclic aromatic hydrocarbons. These are dangerous both to the workers applying the patches, and to other people who may be exposed to the hydrocarbons as they leach out of the asphalt and into the environment.
The leftover grit that's used in wastewater treatment is also problematic. Not only is it non-biodegradable, but because it contains pathogens, it can't be recycled as is. With that in mind, researchers at California State University-Bakersfield set out to make the substance more useful.
They started by mixing wet grit with calcium oxide and magnesium oxide, creating a gritty slurry in which pathogens can't proliferate. Next, they converted that slurry into a mortar by adding a weak acid called potassium dihydrogen phosphate. The result was a chemically bonded phosphate ceramic (CBPC), which the team refers to as a grit assisted patch (GAP).
The lab found the composite to have compressive strength similar to asphalt.
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