Recycling food waste: [3] Benefits of black soldier flies

"Superhero" in waste treatment

Vietnam generates an average of 60,000 tons of domestic waste daily, with organic waste accounting for 50–70%. Yet, most of this waste is still handled through landfilling, leading to soil and groundwater pollution and the release of greenhouse gases. In many localities, especially rural areas and tourist destinations, the decomposition of organic waste causes foul odors, becoming a pressing problem.

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As organic waste increasingly puts tremendous pressure on Vietnam's environment and waste treatment systems, finding a fast, efficient, and eco-friendly solution has become urgent. In recent years, in Da Nang City, a circular agriculture model that treats organic waste on-site, produces animal feed, and supplies organic fertilizer for crops delivered highly practical results. This is the black soldier fly farming model developed by Ms. Le Thi Thanh Nga in Nam Phuoc commune.

Ms. Nga shared that her journey with this model began unexpectedly. One day, she came across a video on social media showing how black soldier fly larvae can treat waste and be used as animal feed, which immediately caught her attention. "I thought this was a very good solution, as it both helps reduce organic waste and creates valuable products. That's when I began to learn more about this insect species," recalled Ms. Nga.

At the beginning of 2023, she decided to experiment at her family's tourist farm. The black soldier fly farming method is quite simple, requiring neither modern machinery nor complex technology. This method just needs a plastic bin for organic waste. The lid is designed with a small tube that attracts the flies to lay their eggs inside. 

"In the natural world, black soldier flies are abundant and likened to a 'superhero' of waste treatment. They prefer humid environments in organic waste dumps, usually rest on leaves, and rarely enter homes like common flies. After a period of time, their eggs hatch into larvae, also known as calcium worms. These larvae are able to consume large quantities of organic waste," Ms. Nga said.

According to Ms. Nga, on average, 1 kilogram of calci worms can consume about 3 kilograms of organic waste per day. Thanks to this, the daily waste at her family’s farm (around 30-50 kilograms), which is mainly leftovers and spoiled vegetables and  fruits, is thoroughly treated without producing foul odors, thereby reducing harmful insects and significantly cutting waste treatment costs.

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As they reach maturity and prepare to transform into flies, the calci worms stop eating and crawl out of the bin through a designed tube. These insects are then used as highly nutritious feed for livestock such as chickens, ducks, and fish. The remaining residue in the bin is composted into microbial organic fertilizer for crops.

"Spoiled or excess vegetables and fruits from the garden become food for the calci worms. Thus, a closed circular model is formed, where all products from the model are fully utilized, leaving nothing to waste. The benefits of black soldier fly farming are clear, not only handling organic waste but also reducing input costs for livestock farming and crop production. That's why I often call this model 'turning waste into wealth,'" Ms. Nga shared.

Replicating the model to reduce pressure on waste treatment

Recognizing the benefits of this model, many people have recently visited Ms. Nga's black soldier fly farming model to observe and learn. Each time, she enthusiastically provides guidance and shares her experience. To achieve the current results, she encountered numerous challenges due to not fully mastering the techniques.

"At the beginning, I did not have a firm grasp on egg incubation and larval care, so the survival rate of the larvae was very low. Weather conditions and insufficient food also slowed their growth. During those times, I had to explore, consult technical materials, and learn from each batch. Thanks to that, the difficulties were gradually overcome, and the model has now been stably maintained," said Ms. Nga.

Besides, the method of caring for larvae is also very important. The larvae must be fed twice daily, in the morning and afternoon, ensuring the amount of food provided is just enough to be consumed within 24 hours. The farming bin is placed in a well-ventilated area, with a maintained temperature of 28–32°C and humidity of 60–70% to ensure optimal larval growth. When these conditions are met, the larvae reach harvestable size approximately every 12–15 days.

"Beginners need to thoroughly understand the techniques before starting, including the lifecycle, farming conditions, and troubleshooting. It’s best to start on a small experimental scale before making larger investments. At the same time, farmers should research both the fertilizer market and the livestock feed market to have multiple outputs for the products," Ms. Nga shared.

The black soldier fly farming model is not just a story of Ms. Nga's farm; it also offers a potential solution to the organic waste problem in many localities. In the future, if scaled up, this solution could help reduce pressure on landfills while generating additional economic value for farmers and small production facilities.

Alongside sharing her experience to spread the model, Ms. Nga said that she plans to expand it to collect and process organic waste from local restaurants and hotels. If successful, her model would both help them reduce waste transportation costs and provide additional sources of animal feed and organic fertilizer.