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Kowloon Hospital has gone green, as the first public hospital to irrigate plants with liquid fertiliser converted from food waste.

The hospital in Kowloon City has handled 400 to 500 kilograms

of food waste every day, including those from the nearby Eye Hospital and Buddhist Hospital, since the introduction of the latest food waste decomposer from South Korea in 2013.

It was the first, among the 19 public hospitals with the machines, to start irrigating their plants with liquid fertiliser transformed from patients’ unwanted food since summer last year after finding ways to extract the liquid through fermentation.

Bosses estimated they will need around 20 per cent less conventional fertiliser.

With the help of enzymes, the waste – mostly rice, vegetables and fruit peels – decompose over 24 hours into a clear, transparent liquid.

Hospital gardeners are given 100 litres of the liquid each day to use on plants, with the rest discharged as sewage.

Jenny Wu Ching-kuen, catering manager for the Hospital Authority’s Kowloon Central cluster, said: “The pulper we used in the past just dehydrated the food waste. We still had to discard them as domestic waste.”

But, while the machine handles more than 90 per cent of food waste of the three hospitals, big bones and shells can not be processed and have to be thrown out.

Dr Lam Chun, the hospital’s quality and safety director, is one of the staff to have benefited from the fertiliser, which has resuscitated the plants he keeps at home.

“The leaves of my [orange tree] all went yellow and had only 50 pieces left...I then gave the food waste fertiliser a try and watered my plant with it once a week,” said Lam. The leaves started to grow back a month later, he said, and the tree resumed normal health within six to eight months.

Henry Ngai Hon-shun, from the Organic Waste Recycling Centre, said that nitrogen, phosphorous and potassium – essential for healthy soil – are generated from food waste during a period of fermentation, which usually takes up to 30 days under natural circumstances.

Browse photography at Denver.Gallery.