In current urban waste systems, the lack of a consistent nutrient balance prevents the production of animal feed. When urban biowaste is used, the larvae produced can be more sustainable than conventional soybean and fishmeal. Since bulk nutrient rich waste from milling and the brewery industry are already used as animal feed, using these types of waste for growing insect larvae would not yield a more sustainable system.
Waste not, want not
Whether in Asia or sub-Saharan Africa, a financially viable insect farm requires a lot of waste. Gold’s research aims to produce a stable and safe process for municipal organic solid waste - which encompasses the different types of waste products found in cities from food markets, households, and restaurants, to, yes, faecal sludge. Since there are so many complex aspects to working with biowaste material - from disease-causing bacteria to inconsistent nutrients, Gold approaches his fundamental research with controlled feeding experiments using sterilized larvae and spiking them with certain microorganisms to see which trigger a change in their growth. Much like humans, larvae need to feed on a formula that includes proteins, carbohydrates, and lipids. The Black Soldier fly feeds only in its larval stage accumulating as much nutrients and as much energy as possible. With access to a nutrient rich diet, they feed for approximately two weeks before they can be harvested for animal feed production or before morphing into a wasp-like fly that lives around one week and is neither a vector for pathogens nor an environmental pest.
For his project, Gold also works with Christian Zurbrügg in the Department of Sanitation, Water and Solid Waste for Development (Sandec) at Eawag and his novel solution plays a role in the World Food System Center’s flagship project on Novel Proteins for Food and Feed. He also works with local processing facilities in developing countries, such as Indonesia, Kenya, and Tanzania.
