A professor in eastern China has set up has set up a fly farm to recycle kitchen waste, and now says he is processing 3,000 tonnes of it a year, according to media reports.
Zhang Zhijian, an associate professor with Zhejiang University’s school of environment and resources, opened the farm three years ago to put his knowledge of recycling into practice.
He told Beijing News that black soldier flies like to feed on rubbish, faeces and rotten fruit as maggots, and their metabolisms help decompose the waste, producing by-products which are then sold as fertiliser and animal feed.
He said when the farm was first established in 2016, no locals were willing to dump their kitchen waste with him.
But thanks to efforts by the local authorities to promote recycling, it is now dealing with up to 12 tonnes a day, according to the Qianjiang Evening Post.
He insisted that the process was clean and safe, because the flies do not carry pathogens or microorganisms.
The adult flies only drink water and can survive about 10 days, Zhang said, while the maggots, or larvae, feed on waste.
He set up thirteen green houses in 2016, one dedicated to mashing and stirring kitchen waste before adding probiotics, which turns the waste into warm beds for eggs to grow into maggots and later flies.
The other greenhouses are stacked with layers of trays, which are covered with the treated kitchen waste to accommodate the maggots.
The nitrogen, phosphor and oils in the waste are consumed by the maggots, which thrive on the diet.
Their droppings can be made into organic fertiliser, used by residents to grow flowers, while the larvae, which sell for 10,000 yuan (USUS1,500) a tonne, can be used to feed chickens, fish, shrimp and birds, according to the report.
“I started field experiments in 2014,” he told The Beijing News. “Ten tonnes of waste can eventually yield 1.2 tonnes of flies.”