Black Soldier Fly Larvae Transform Food Waste into Nutrient-Rich Soil Booster
A groundbreaking solution to food waste and soil fertility is taking root in Cape Town. The larvae of black soldier flies are converting spent brewers grain, which accounts for around 40 million metric tons of global food waste annually, into a nutrient-rich by-product called 'frass'.
Frass, with its near-neutral pH, is ideal for cultivating staple vegetables like cabbages, onions, lettuce, and cauliflower. It enhances soil fertility, promotes nutrient cycling, and improves soil structure. The beneficial microorganisms in frass contribute to soil health and plant growth. In a closed-loop system, frass can benefit fields where barley grains are cultivated, ensuring healthy crop growth for the next harvest.
AgriProtein, a Cape Town-based organization, uses black soldier fly larvae to convert agricultural waste into a high-value, nutrient-rich feed ingredient for animal and aquaculture feeding. They can process up to 600,000 kgs of agri-processing waste per month. Frass can also control unpleasant odours and improve water retention in soil, making it suitable for use in public spaces and regions with water shortages like Cape Town.
Frass, costing R4,000 per ton compared to conventional fertilizers ranging from R12,000 to R24,000 per metric ton, offers a cost-effective and sustainable alternative. Replacing just 1% of the City of Cape Town's current usage of soil amendment products with frass would be a significant step towards embracing alternative fertilizer approaches.
