Citizen Farm has been using the black soldier fly to help grow its vegetables, as food for its fish and to help tackle food waste – the first in Singapore to incorporate these insects as part of farming practice.

The “closed loop” farm runs on a circular economy approach, by feeding the insect larvae with food waste from restaurants and supermarkets, turning this into nutrient-rich fertiliser.

Once the larvae transform into pupae, the insects are fed to jade perch fish which the farm rears. The fish subsequently secrete waste that becomes fertiliser for its vegetables.

Leftover agriculture waste – or produce that cannot be sold – is fed to the larvae, which then produces waste that becomes fertiliser.

The farm currently produces around 150kg of vegetables and fish a month, and goes through the same weight of food waste a day for its insect farm, which currently houses about 10kg of the black soldier fly’s pupae.

“The purpose of closed loop farming is to look at waste as a resource which we can then utilise to be looped back into our food cycle,” said Mr Darren Ho.

There are also wider benefits to running such a closed loop system in Singapore as opposed to conventional farming, according to Professor William Chen, the director of the food science and technology programme at Nanyang Technological University. “Closed loop farming provides a very attractive alternative in terms of sustainability of food production, because we rely less on land and use less water and energy,” he said.

He noted that the technology was not a new one that had come “out of nowhere” but one that had been used in neighbouring countries such as Indonesia and Thailand for more than a thousand years.

“(For example), in rice paddy fields, the farmer will keep the ducks or fish. So it’s already closed loop because the fish would take the discharge from the duck and the fish discharge will become fertiliser for the rice,” he said.

Source: ‘Closed Loop’ Urban Farm Tackles Food Waste with Insects