Insects nourished by kitchen and other organic waste could be a more sustainable way to provide protein for China’s population, as conventional sources become increasingly scarce, according to Chinese scientists and international industry experts.
The insect-based proteins make a highly nutritious animal feed which is better for livestock health and addresses dwindling fish stocks and the substantial environmental concerns around intensive livestock farming.
Urban residents produce large amounts of biodegradable kitchen scraps and other matter every day which is literally going to waste, according to the Shanghai Observer, a news agency owned by the city’s party committee.
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“In Shanghai alone, the average daily output of wet waste was 9,329 tonnes from March to July 2022. Yet the city could only process 8,200 tonnes a day, leaving a deficit of about 1,100 tonnes each day,” it said.
Insect farming technology offers a potential solution to both problems. Worms fed with pre-processed wet waste convert the organic matter into a rich source of nutrients – a process that is efficient, harmless and sustainable.
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An insect farm established by the The Shanghai Urban Construction Investment Corporation is testing the process, converting 50 tonnes of pre-processed wet waste into 11 tonnes of protein-rich larvae and 12.8 tonnes of organic fertiliser daily.
According to a peer-reviewed paper published by the Guangdong Chemical Industry journal, the farm uses the black soldier fly (BSF), from the tropical grasslands of South America.
The insect was chosen for its short life cycle – around 35 days – and strong resilience, making it ideal for cultivation, according to lead author Ma Cong, manager of the project.
“By crushing the waste and adjusting its water content, scientists create a suitable environment for BSF larvae. Larvae in the third-stage can grow into high-protein, high-fat fifth-stage BSF larvae in one week,” he said.
“The droppings from these larvae are high in organic matter, nitrogen, phosphorus, and potassium, and also contain a wealth of beneficial bacteria, making it an excellent new type of organic fertiliser,” Ma added.
The harvested larvae can be used to make animal feed, pet food, bio-oil and other products, according to the paper. The process is sustainable, with some of the larvae selected to lay eggs after pupation.
While insect farming is in its early stages in China, the process has been proven in the Netherlands, where leading company Protix converts 65,000 tonnes of waste into 14,000 tonnes of insect larvae.
The resulting insect-based products for pets, fish and livestock had a retail value of more than 70 million euros (US$77 million) in 2023.
According to Protix CEO Kees Aarts, the nutritional and environmental advantages of insect-based proteins underscore their potential as a vital resource for the future, starting with their use as an animal feed.
“Insect-based proteins bring about improvements in the liver quality and skin health of salmon, [as well as] the fur, breath, and digestive health of dogs, and reduce diarrhoea and mortality rates in piglets and chickens,” Aarts said.
“BSF has high feed efficiency, short life cycles, ability to eat low grade organics – and they keep eating before the adult phase. It consumes much less land and water to create an equal quantity of proteins [compared with] poultry meat or beef offal.”
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In addition to providing a more sustainable alternative to traditional animal farming, the insects’ diet can be tailored to include things other than daily household waste.
According to Protix, its years of experience mean it can match waste streams to a suitable diet for the insects, expanding the potential to recycle most of a region’s safe and legal organic material into a valuable protein source.
In China, where insect farming’s potential growth is enormous, the treatment of wet waste to make sure impurities are screened out, will be essential.
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According to Ma’s paper, securing the raw materials for insect breeding is the cornerstone of the technology, with impurities such as plastic bags affecting the growth efficiency of BSF.
“Only by properly treating wet waste, through steps like sorting, collecting, transporting, screening, and crushing, can we ensure a smooth BSF breeding,” Ma said.
Another key focus is to increase the economic and environmental benefits of the process. “Our products currently include feed, bio-oil and organic fertiliser. However, the public’s understanding and acceptance of these products need to improve,” he said.
According to Aarts, the future of insect-based proteins is promising.
“As traditional protein sources continue to deplete and climate change concerns increase, insect-based proteins offer a sustainable, nutritious, and efficient alternative,” he said.
More from South China Morning Post:
- Typhoons Khanun, Doksuri add to China’s food security headache, as export bans push up global prices
- China’s Xi Jinping sharpens focus on food and mineral supply chains
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