Khanal, Robert Olivier, and graduate student K.C. Surendra show the products of
Most people are familiar with vermicomposting, using worms
to break down garden and kitchen waste and boost the fertilizer content of the
resulting compost. But as Molecular Biosciences and Bioengineering researcher
Samir Khanal explains, larvae generate a similar high-quality soil amendment
while eating more, and more diverse, waste. And they also create two further
products: fuel and feed.
Food scraps, including fats and meat that can’t go into
ordinary compost, are placed in a BioPodTM, an ingeniously designed compost-type bins, to
be eaten by black soldier fly grubs. These voracious eaters become very fat,
and this fat is a valuable source of fuel. The grubs are heat-dried to reduce
moisture content, then pressed for oil. “There’s nothing more valuable than a
liquid fuel source,” avers Robert Olivier, Dr. Khanal’s collaborator and BioPodTM creator; it’s far more
versatile and easy to use than a gas.
Desirable as it is, the fuel may not be as important as the
other end-product, the feed. After dried larvae are pressed, the resulting meal
is the perfect blend of protein and fat for feeding chickens and fish. Mr.
Olivier is running a trial with 120 chickens on a Maui farm now; final results
aren’t in, but he confirms, “They love it. And the eggs are phenomenal!”
Tilapia and other fish used in aquaponics also thrive on the meal, providing a
much-needed solution to the conundrum of trying to promote food sufficiency
through aquaponics when feed is largely imported from the Mainland.
Dried larvae can be turned into larval protein meal and oil.
Larval farming is potentially a self-perpetuating cycle on
both large and small scales. Self sufficiency-oriented homesteaders can use
their own scraps to feed their own BioPodTM of larvae, using the pressed oil in oil lamps
or oil-fueled heating devices and feeding small flocks of poultry and tanks of
fish. But Dr. Khanal and Mr. Olivier envision the citywide implications: Trucks
bringing food waste from restaurants and supermarkets to facilities with much
huger BioPodTM bins
could be powered by larval biodiesel—the oil, amended for consistency and
stability. This biodiesel, they calculate, would easily power the machines
pressing the dried larvae—and the heat generated by the pressing is just the
temperature needed to dehydrate the next batch. And commercial-grade feed,
pressed into pellets, could be trucked to feed-supply stores all over the
state, again in trucks fueled by larvae. It’s an exciting vision…one they’re
already working to bring to reality.