The Black Soldier Fly, Hermetia illucens Linnaeus (Diptera: Stratiomyidae): A Novel Approach to Combat Food Waste in Windsor-Essex.
Date of Award
Hermetia illucens, Black soldier fly, Food waste, Windsor-Essex, Larva
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Within Ontario alone, approximately 3.7 million tonnes of organic food waste is generated yearly. This waste includes food scraps, wasted food, and plant wastes such as leaves, plant stems, and fruit. Most of it is transported to landfills for composting each year, but the use of landfills as a method of waste management is not sustainable. It adds strain to the environment by releasing harmful greenhouse gases and by demanding landfill space. The current protocols set by the Ontario government, while promising, do not address methods that support the safe disposal of organic waste and conversion into valuable end products that could contribute economic benefits, the black soldier fly presents an opportunity to address this lack.
The black soldier fly, Hermetia illucens Linnaeus (Diptera: Stratiomyidae) has the potential to reduce organic waste, including kitchen waste and manure. My dissertation investigated the black soldier fly as a means of waste management within Windsor-Essex, and its role in converting food waste into economically valuable end products. I investigated the black soldier fly’s ability to consume local municipal food waste from within this region. The flies reduced approximately 70% of the waste, and allowed me to develop a baseline for black soldier fly waste reduction within the area. As I measured slower development to adult and reduced waste reduction efficiency compared to a control diet of poultry feed, I investigated the potential role of pre-digestion and fermentation with beneficial microbes in the black soldier fly waste reduction process with the goal of improving the baseline waste reduction efficiency. Fermentation time impacted development and waste reduction efficiency of the black soldier fly. Diets fermented for 0 days had a positive influence on the survival and bioconversion efficiency of the black soldier fly, while diets fermented for 2 days had a positive influence on the relative growth rate and waste reduction efficiency. Diets fermented for longer than 2 days negatively affected the black soldier fly development, growth and waste conversion efficiency. The results show that using beneficial microbes is not straightforward and might depend on the purpose of the bioconversion process. Since larval density influences the waste conversion efficiency, it is essential to rapidly quantify egg numbers for introduction to waste streams. Thus, I developed a commercially-scalable model to quantify the number of eggs oviposited by female black soldier flies based on egg mass weight or volume. The model was created using linear regression of egg masses across a range of sizes and relating egg number to relate egg mass weight or volume. Once the linear equation was developed, it was validated with a new set of egg masses of varying sizes. Egg mass volume and weight were positively correlated to the number of eggs deposited in an egg mass, and either can be used to estimate the number of eggs within egg masses. Finally, I investigated the use of black soldier fly processing residue (residual wastes, shed exoskeletons, and frass) as a fertilizer for an economic value-added product. Tomato seeds were planted in an inert growing media (coconut coir) with three concentrations of the processing residue and compared to a control of slow-release fertilizer. The two highest concentrations of black soldier fly processing residue resulted in failed germination, whereas the lowest concentration supported germination and growth with larger root and shoot biomass, larger leaf area, and a higher number of flowering trusses compared to the slow-release fertilizer treatment. Together, my research provides valuable new insight into the black soldier fly’s waste conversion ability, an essential tool for commercially-scalable methods of quantifying egg numbers in a non-destructive and timely manner that allows the establishment of optimized feed rates for the black soldier fly in waste management, and a useful end product to promote a circular economy.
Okpara, Patricia Obianuju, "The Black Soldier Fly, Hermetia illucens Linnaeus (Diptera: Stratiomyidae): A Novel Approach to Combat Food Waste in Windsor-Essex." (2023). Electronic Theses and Dissertations. 8965.