Scientists are tackling growing food waste by using a small-scale bioreactor that relies on black soldier flies to convert scraps into animal feed and fertilizer. The device was designed to offer a low-cost, local option compared with large industrial facilities, and it can be built from off-the-shelf materials and maintained by one person.
A paper coauthored by entomologist Kerry Mauck of the University of California, Riverside describes the bioreactor and its effectiveness. The team tested the setup with food waste from a campus dining hall. With basic oversight the system became stable and produced about a pound of larvae per square yard every day.
The main product is frass, the insect manure, which the researchers found in greater quantities than the larvae themselves. Frass can act as a soil amendment, and insect fragments from molting seem to stimulate plant defenses and improve soil microbial health. Keeping the bioreactor running requires climate control, occasional water and wood chips, and monitoring of temperature and pH to avoid harmful anaerobic conditions.
Difficult words
- bioreactor — machine using organisms to convert waste materials
- frass — insect manure used as fertilizer for plants
- larva — young insect before it becomes an adultlarvae
- entomologist — scientist who studies insects and their biology
- amendment — material added to soil to improve its quality
- anaerobic — condition lacking oxygen that affects organisms
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Discussion questions
- Would you consider using a small bioreactor for food waste in your home or community? Why or why not?
- What are some benefits and possible problems of using insects to recycle food waste?
- How might local food waste systems like this change a campus or neighbourhood if many people used them?
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