Waste cooking oil used to make slow release fertiliser
Waste cooking oil collected from cafes and restaurants has been used to make a controlled-release fertiliser that results in better plant health and less wasted nutrients.
The fertiliser uses the waste canola oil and sulphur — a waste product from the petroleum industry — to form a degradable polymer coating to encase each fertiliser pellet.
Dr Justin Chalker and his team developed it at the Institute for NanoScale Science and Technology at Flinders University in South Australia.
Dr Chalker said the food waste product could make an important contribution to the circular economy.
“You can use it for frying up food and then you can use it again for something that’s used to grow more food,” he said.
“We can control the release of the nutrients through the size of the particles we manufacture and the amount of the nutrient that we trap inside the polymer.
“What’s unique about our material compared to other slow release fertilisers is the material that holds in the nutrients is made entirely from waste and we show in this paper that it can degrade, which is important for the long-term persistence of this material whether it’s in potted plants or the environment.”