Carlos Antonio Lopez Manzano
Project
From waste to resources: Converting Canada geese feces into protein and plant fertilizer using the black soldier fly (Hermetia illucens)The management of fecal waste from superabundant species in urban green spaces is a central topic in environmental sustainability and public health. In North America, the Canada goose (Branta canadensis) is particularly problematic because of its large abundance in public spaces, resulting in large quantities of droppings that negatively affect the recreational, aesthetic, and hygienic quality of the environment. Here, we evaluate the potential of black soldier fly (BSF; Hermetia illucens) larvae to bioconvert Canada goose feces into protein, while producing frass that can be used as plant fertilizer. We performed an experiment that evaluates BSF performance (Larval growth performance, adult body weight, and adult lifespan) under three diet treatments: a standard Gainesville diet (control), a mixed diet containing 50% goose feces and 50% Gainesville, and a diet consisting entirely (100%) of goose feces. We found that the BSF larvae can survive and complete its larval development in both 50% and 100% fecal treatment diets, albeit the growth rate, adult body weight, and adult lifespan decreased with increasing concentration of feces. We also conducted an experiment that assesses growth performance of duckweed (Lemna minor) across different fertilization treatments, including Hoagland’s media (control), and three concentrations (5, 10, and 20 g·L-1) of fresh goose feces and insect frass (derived from 100% goose feces). Duckweed growth was fastest in the frass treatment at concentrations of 10 g·L-1, suggesting that BSF larvae increased nutritional value of goose feces for the duckweed. Our study suggests that BSF can be used to bioconvert Canada goose feces into proteins while generating a valuable plant fertilizer.
