Investigating production capabilities and uses of Black Soldier Fly Larvae (BSFL) for organic waste processing in the urban environment

Project Overview

FS24-375
Project Type: Farmer/Rancher
Funds awarded in 2024: $19,737.00
Projected End Date: 03/31/2026
Grant Recipient: Future Acres Urban Farming
Region: Southern
State: Virginia
Principal Investigator:
Dave Littere
Future Acres Urban Farming

Commodities

No commodities identified

Practices

No practices identified

Proposal summary:

Among the popular insects used
for composting organic waste, black soldier fly larvae (BSFL) are
especially attractive because of their ability to thrive and
quickly decompose many different types of organic waste, their
classification as “not a nuisance species” and their use as
protein for livestock feed (Romano, 2023). BSFL quickly converts
waste material to insect biomass- at conversion efficiencies of
44%, 67%, 74% and 98% for manure, kitchen waste, fish and
vegetable/fruit waste respectively (Nguyen et al., 2015). The
complete cycle of food waste to mature BSFL is uniquely quick and
requires only 1-3 weeks (Lopes et al., 2022).  Additionally,
Black soldier fly larvae are considered easier to manage and
harvest than other insects used for composting because they
exhibit a “self harvesting” behavior where maturing larvae will
exit their active food habitat for a dry pupating environment
(Terrell, 2022). Technically advanced operations are run in
European and North American companies, such as EnviroFlight,
Oberland Agriscience, and Eawag, while simple but highly
efficient systems are operated out of African and Indonesian
countries like the Marula Protein Hub, ProteinMaster Nairobi, and
BSFL Colonies.

This natural technology has
become very popular over the last decade, with plenty of
available information and research being conducted on how to
improve the bioconversion rates from the wasted nutrients to
usable macronutrients, which feedstock mixes are best for BSFL
decomposition, how best to incorporate BSFL into existing
livestock and pet feeds, and how to grow the BSFL to maximum size
most efficiently. To do this, BSFL must be maintained under ideal
environmental conditions, including parameters such as humidity,
nutrient composition, physical properties, temperature, and
oxygen level in order to optimize bioconversion
rates. 

 

In addition to their unique
bioconversion abilities, BSFL makes for a nutritious, and
sustainable, supplemental livestock feed once they are through
their larval lifecycle. Crude protein and crude lipid contents of
BSFL meal range between 40%-44% and 15%–49%, respectively,
depending on the processing methods and substrates used (Tran et
al., 2015). According to EnviroFlight, BSFL production offers a
“protein per acre” measurement that is unmatched to any other
source of traditional protein feeds, with up to 1,000,000 pounds
of protein per acre, compared to soybean with just under 1500
pounds of protein per acre as a double harvest. To extend the
list of benefits that BSFL has to offer, there is research being
done on the extraction efficiencies and techniques of chitosan, a
derivative of chitin, and melanin. Both of these compounds, found
abundantly in the shells of the BSF and the larvae, are being
used in industries such as cosmetics, internal medicine, and
micro-electronics (Abidin, 2020). 

 

Future Acres is currently
planning and building a simple small-scale, vertically integrated
BSFL composting system and aims to start processing urban food
waste in early 2024. Our system will be environmentally
controlled and vertically integrated to save space in the urban
environment, which creates a novel system. Having the ability to
control the temperature, humidity to optimal conditions, and
having vertical integration, our system has the potential for
extremely high efficiency. Utilizing common urban food waste as
the input, we want to quantify the maximum capacity of our system
for food decomposition. This will create a benchmark for other
urban farmers interested in incorporating insect farming to their
operations.

 

Additionally, we want to record,
and make available to other urban farmers, the production
capabilities of livestock feed, and frass for additional revenue
sources and summarize the issues that face urban farmers when
running an urban BSFL composting system. Finally we want to begin
to assess the use of frass in popular urban agriculture
production systems like hydroponics and microgreens. 

 

While there are examples of using
BSFL for food waste processing, there is very limited information
specific to small-scale, urban, indoor environments of the
Southern United States. For urban farmers that are interested to
start BSFL composting, basic questions need to be answered like -
how much mixed urban waste can be processed with a BSFL system?
How much revenue can be generated from an urban BSFL composting
system? What are context specific concerns/management practices?
How much compost and livestock feed can I produce?

 

Ultimately the question that
needs to be answered is- Is it worth adding BSFL composting to an
urban farm operation?. There's an absence of specific information
and tailored methods for small-scale, highly urbanized
environments; there’s confusion about the processing capacity for
these systems when they’re optimized for food waste processing,
and there are limited farmers with experience to share. With the
help of the SARE producer grant, we aim to fill these gaps in
knowledge about BSFL composting in urban contexts. 

 

Abidin, N.A.Z.; Kormin, F.;
Abidin, N.A.Z.; Anuar, N.A.F.M.; Bakar, M.F.A. The potential of
insects as alternative sources of chitin: An overview on the
chemical method of extraction from various sources. Int. J. Mol.
Sci. 2020, 21, 4978. [Google Scholar] [CrossRef]

Lopes IG, Yong JWH, Lalander C.
2022. Frass derived from black soldier fly larvae treatment of
biodegradable wastes: A critical review and future perspectives.
Waste Management 142:65−76

Tran, G.; Gnaedinger, C.; Mélin,
C. Black soldier fly larvae (Hermetia illucens). Feedipedia, a
programme by INRAE CIRAD, AFZ and FAO. Last updated on 20 October
2015, 11:10. Available online:
https://www.feedipedia.org/node/16388 (accessed on 20 July
2022).

Nguyen, T. T. X., Tomberlin, J.
K., & Vanlaerhoven, S. (2015). Ability of Black Soldier Fly
(Diptera: Stratiomyidae) Larvae to Recycle Food Waste.
Environmental Entomology, 44(2), 406–410.
https://doi.org/10.1093/ee/nvv002

Project objectives from proposal:

We will run a study to:

  1. Find management practices that
    maximize mixed urban food waste breakdown using BSFL and
    then 
  2. assess the production
    capabilities and value of BSFL (lbs) and frass production (lbs)
    for livestock feed and soil amendments.

To maximize decomposition of
organic waste, adequate oxygen and BSFL density need to be
present within the organic matter mix. If these factors are not
optimized, anaerobic conditions are created in the organic
matter, and BSFL organic matter breakdown efficiency is
reduced.  For this reason we will assess a few different
ventilation rates and BSFL density rates for our specific
vertically integrated system. Each treatment plot will be a tube
filled with 25 lbs of homogenized organic waste receiving a
treatment of ventilation rate and BSFL density. 

Variables:

  • The independent variables of
    interest are: optimal ventilation rate and BSFL density
  • The dependent variables of
    interest are:

    • Amounts (lbs) of organic
      matter decomposition
    • Weight (lbs) of BSFL
      production
    • % frass produced
  • Control:

    •  the pounds of
      processed food scraps contained in each composting pipe (25
      pounds of food scrap)
    • the ambient temperature of
      the air in the facility (will be kept within the range
      75-85 degrees)
    • Food scrap input: the
      mixture of food scrap contained in each treatment (mix of
      most common “urban food scrap waste”)

 

The experimental design will be a
split-plot, with ventilation as the main treatment, and BSFL
density as the
experimental design
sub-plot
treatment. See experimental design in the image to the right;
each circle represents the composting tube that will hold 25 lb
food waste : 

Treatments: 

To determine the optimal ventilation
rate
we will
measure the effects that different rates of airflow have on our
system bioconversion rate. 

We will introduce airflow to the
pipes for five minute intervals at 3 different treatments:

  1. Treatment 1: every three
    hours,
  2. Treatment 2: every six
    hours
  3. Treatment 3: every eight
    hours. 

Temperature and humidity will be
monitored throughout the experiment to compare how the different
rates of airflow affect BSFL activity levels. At the end of a 2
week feeding period, the % of biomass converted will be
assessed. 

To determine the optimal amount of young
BSFL
to add to each
system to maximize speed of breakdown, we will be experimenting
with three amounts of larvae added to the 25 pounds of food
waste.

  1. Treatment 1:  7,000,
    5-day-old BSFL (5-dol),
  2. Treatment 2: 8,500, 5-dol
    BSFL
  3. Treatment 3: 10,000, 5-dol
    BSFL

These treatment amounts are
guided by previous guidelines and measurements taken by Christian
Zurbrügg et. al. Their research in Eawag’s commercial composting
system utilized around 300-360 BSFL per pound of food scraps
(Note: 10,000 to 12,000 BSFL/15 kg food scraps = 303 to 363 BSFL
per lb food scraps. Our control amount will be based on 11,000
BSFL/15 kg of food scrap, or 333 BSFL/lb of food scrap. Total
BSFL for control will be 333 BSFL x 25 lb food scrap = 8,325
BSFL)..

Data Collection: 

At the beginning of each study
iteration, 

  1. the composition of the organic
    matter input will be recorded as: %meat/protein;
    %vegetables/fruit/mushroom; %breads/pastas. 

Throughout the
study: 

  1. Temperature and humidity of
    each plot will be recorded daily
  2. Outdoor temperature and
    humidity will be recorded daily

End of study:

  1. mature BSFL weight (lbs) after
    composting

    1. In order to measure BSFL
      growth rates, after 2 weeks of running the system, we will
      sample the weights of 100 BSFL from each of the
      experimental sub-plots. In order to measure the food scraps
      conversion, we will sift out and weigh remaining food
      scraps from each subplot. In order to measure the frass %
      we will estimate the usable frass from each sifted
      sub-plot.
  2. the amount (lbs) of food scraps
    leftover after composting

    1. Food scraps will be sifted
      from frass and weighed.
    2. This will help us calculate
      the amount of food scraps converted
  3. % frass produced

    1. Remaining frass after
      sifting will be weighed
  4. observe/record the general
    activity level of the BSFL during feeding. 

We will repeat the study 3 times
during winter and summer season, respectively, with a total of 6
replications of the study. This will help capture the variation
of seasonality effects on our indoor climate, to ensure
significance for statistical analysis (while we wish indoor
climates were 100% controllable, this is simply not the case. In
the heat of the summer our environment is slightly higher
temperature and humidity). It is possible, that during the heat
of the summer, or cool of the winter, that optimal ventilation
and BSFL densities are different.

From the conclusion of the
ventilation and BSFL density study, an optimal ventilation and
BSFL density will be determined. Then the revenue of livestock
feed and frass capability of this system will be assessed. The
data to assess this will already have been collected through the
study. 

The data will be analyzed using R
software with ANCOVA, to assess the effects of ventilation hours
and population densities, and their interaction effects on BSFL
weight, and organic matter conversion % and end-product frass
%.


By
the end of our study, we will have the data to share the amount
of general urban organic waste that can be processed by an urban
BSFL operation and the potential production/revenue from
livestock feed and soil amendment production. 

References: 

Kinasih et al., 2020.Performance
of black soldier fly, Hermetia illucens, larvae during
valorization of organic wastes with changing
quality. 

Lalander et al., 2019.Effects of
feedstock on larval development and process efficiency in waste
treatment with black soldier fly (Hermetia illucens).

Lu et al., 2021. Effects of
different nitrogen sources and ratios to carbon on larval
development and bioconversion efficiency in food waste treatment
by black soldier fly larvae (Hermetia illucens).

Lopes et al., 2022. Frass derived
from black soldier fly larvae treatment of biodegradable wastes:
A critical review and future perspectives. 

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.