Waste-green infrastructure nexus: Green roof promotion by digestate and digestate biochar from food waste.

[Display omitted] • Urban food waste—green infrastructure nexus is feasible. • Food waste digestate significantly promoted green roof plant growth and functions. • Food waste digestate is better than digestate biochar in green roof promotion. • 20% performed better than 10% both in digestate and digestate biochar. Waste—Green Infrastructure Nexus is crucial to mitigate carbon emissions in waste disposal and promote eco-functions of green infrastructure in a circular bio-economy. Our purpose is to verify the feasibility of the nexus via "food waste anaerobic digestion — digestate/digestate biochar — green roof promotion". The results found that food waste digestate and digestate biochar significantly promoted green roof plant growth, evapotranspiration, rainwater retention, runoff reduction, and prevention of nutrient leaching. Digestate treatments were better than digestate biochar for the green roof promotion. The promotion ranked consistently with 20 % digestate > 10 % digestate > 20 % digestate biochar > 10 % digestate biochar > control in stolon growth, leaf emergence, branching of Paspalum vaginatum , green roof establishment, rainwater retention, runoff reduction, and the leaching of nitrogen, phosphorus, potassium. This study demonstrated that food waste could be regenerated to promote urban green infrastructure to form a circular bio-economy by the Waste—Green Infrastructure Nexus. [ABSTRACT FROM AUTHOR]