Progress report for FS24-375
Project Information
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
We will run a study to:
- Find management practices that maximize mixed urban food waste breakdown using BSFL and then
- 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 
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:
- Treatment 1: every three hours,
- Treatment 2: every six hours
- 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.
- Treatment 1: 7,000, 5-day-old BSFL (5-dol),
- Treatment 2: 8,500, 5-dol BSFL
- 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,
- the composition of the organic matter input will be recorded as: %meat/protein; %vegetables/fruit/mushroom; %breads/pastas.
Throughout the study:
- Temperature and humidity of each plot will be recorded daily
- Outdoor temperature and humidity will be recorded daily
End of study:
- mature BSFL weight (lbs) after composting
- 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.
- the amount (lbs) of food scraps leftover after composting
- Food scraps will be sifted from frass and weighed.
- This will help us calculate the amount of food scraps converted
- % frass produced
- Remaining frass after sifting will be weighed
- 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.
Cooperators
- (Researcher)
- (Researcher)
- (Educator and Researcher)
Research
This is the new/optimized setup as compared to using pipes for rearing and ventilation. This is opposed to the initial setup for the experiment, where pipes were being used to house the BSFL while they eat the food waste. There was not enough air space in the tubes to produce viable results.
Additionally, we switched the ventilation rates from 5 min intervals every 2, 3, and 6 hours to 3 min intervals every 10, 20, and 30 mins.
Educational & Outreach Activities
Participation Summary:
Our goal is to share the findings and experience from this grant with as many urban food system stakeholders as reasonably possible. We plan to do this through a local, regional and virtual outreach approach, to allow dissemination of information as broadly as possible.
- Locally-
- We will host an on-farm demonstration, coordinated through the Fairfax Virginia Extension office. The on farm demonstration will show our BSFL system and share the results of our different studies.
- Additionally we will present at a local urban farmer conference that receives over 1500 local farmers/gardeners in the DMV area - Rooting DC
- Regionally-
- We will present our findings and experience to the RVA Urban Ag Conference
- Virtually-
- We will create 4-5 videos that detail our studies, experiences and findings.
- Video subjects may be:
- Why ventilation and BSFL matter for BSFL efficiency- show different results from different ventilation
- Different opportunities to create revenue from BSFL- share frass and livestock feed production capabilities
- Explain business of urban BSFL composting services
- Miscellaneous lessons learned
- Show basic set up, and share food waste decomposition capabilities
- Video subjects may be:
- We will create 4-5 videos that detail our studies, experiences and findings.
We want to stay open to attending other conferences or meetings, or create additional videos, throughout these 2 years if there is demand and opportunities present themselves. We plan to stay in close contact with our local extension agents to be aware of other potential opportunities.
Year 1 update: Outreach Activities
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- 10/1/24: Fairfax County Park Authority site visit and demo; discussed county pilot program (2 people)
- 10/10/24: Fairfax County farmers market site visit and demo; how we compost food waste collected from the farmers markets (11)
- 10/20/24 - 4/20/25: George Mason University site visits and demo; discussed technological innovation capstone project (6)
- 11/8/24: BSF Breeding site visit and demo; egg sourcing for operations (1)
- 11/14/24: SARE administrator site visit
- 11/22/24: Fairfax EDA site visit and demo; discussed potential grants and additional site locations (2)
- 12/16/24: University of DC site visit with environmental sustainability professor (1)
- 2/2/25: Friends of Green Spring talk; presented BSFL composting technology along with SARE research (32)
- 2/6 - 2/8: Maryland Association for Environmental and Outdoor Education conference exhibit; displayed BSFL composting tech at an exhibit table and talked through SARE research (54)
- 2/18/25 - 4/24/25: Georgetown Eco Consultants BSFL Composting presentation and final project (8 students, 44 audience)
- 2/19/25: RestonStrong site visit and demo; discussed non-profit and food bank partnerships (3)
- 2/19/25: Centreville HS Future Business Leaders of America site visit and demo (4)
- 2/27/25: Plant Futures at GMU site visit and demo (3)
- 3/6/25: Presented BSFL composting and SARE research to Centreville HS FBLA group (18)
- 3/17/25: UDC environmental sustainability students site visit and demo (6)
- 3/26/25: Fairfax County Public Schools site visit; discussed partnership with FCPS (2)
- 3/26/25: North American Coalition for Insect Agriculture site visit and demo; discussed future of insect ag. for waste management and increasing research interest such as SARE (1)
- 4/5/25: Presented SARE research and BSFL composting at the Richmond Urban Agriculture Conference (40)
- 4/24/25 - 5/16/25 Various Earth day events across Fairfax County with BSFL composting and SARE research displays (30)
- Total outreach: 261 people
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Learning Outcomes
Substrate Moisture Control Variance
Commercial vs. Research Applications
Project Outcomes
This Year One progress report summarizes the initial setup, exploratory experiments, and preliminary findings for Project FS24-375, funded by Southern SARE with $19,595.00. The project focuses on optimizing a small-scale, vertically integrated BSFL composting system for urban food waste processing in Virginia. In year one, we completed the construction of a tray-based system in stacked shelves, conducted exploratory trials on different food waste (FW) types, and tested variations in ventilation rates and BSFL densities. Preliminary results from FW exploration indicate that mixed post-consumer FW achieved the highest bioconversion rates (up to 90% in some trays) with a standard 14-day growth stage, though moisture fluctuations posed challenges. Coffee grounds and bread products showed slower conversion and lower larval weights. Optimal practices and further refinements are planned for Year Two. Outreach efforts included preparations for a presentation at the Richmond Urban Ag Conference in April 2025, reaching about 40 urban farmers and stakeholders. Additionally, we hosted sustainability-focused municipalities, environmental government offices, public schools and universities, and non-profits for site tours and demos of our BSFL composting system, reaching another 220 stakeholders. Budget utilization is on track, with approximately 50% expended primarily on system construction and initial supplies.
Project Objectives
As outlined in the original proposal:
- Identify management practices that maximize mixed urban food waste breakdown using BSFL.
- Assess the production capabilities and value of BSFL (lbs) and frass production (lbs) for livestock feed and soil amendments.
Progress: In Year One, we advanced Objective 1 through system setup and exploratory trials on FW types, ventilation, and BSFL densities using a split-plot design with trays. Three winter-season replications were completed, focusing on indoor climate variations. Data collection for Objective 2 included measurements of BSFL weight, frass percentage, and FW conversion, with preliminary revenue estimates based on market values (e.g., $2/lb for BSFL as livestock feed and $0.50/lb for frass as soil amendment). Full statistical analysis using R software (ANCOVA) is underway, with summer replications scheduled for Year Two to capture seasonality effects.
Research
Deviating from the original design, the system was constructed as a vertically integrated setup using stacked shelves with trays, each holding approximately 20 lbs. of homogenized urban food waste. The setup included environmental controls for temperature (maintained at 75-85°F) and humidity, with fans for ventilation. This adapted from the original tube-based design to better suit urban space constraints, as explored in practical considerations.
Independent variables:
- Ventilation rates: 5-minute airflow intervals every 2 hours (Treatment 1), 3 hours (Treatment 2), or 6 hours (Treatment 3) based on initial testing.
- BSFL densities: 7,000 (Treatment 1), 8,500 (Treatment 2), or 10,000 (Treatment 3) 5-day-old larvae per tray.
Dependent variables measured: Organic matter decomposition (lbs), BSFL production weight (lbs), and % frass produced. Additional exploratory variables included FW types: coffee grounds, bread products, and mixed post-consumer FW.
Discussion and 2025 Work Plan
Three winter replications were conducted from November 2024 to February 2025, with additional exploratory trials on FW types to inform optimization. Key preliminary findings:
- FW Exploration: A comparison of substrates revealed significant differences:
- Ventilation and Density: Early data suggest the initial proposed ventilation rates were insufficient. Further research and trialing showed that due to the limited amount of air in the enclosed environment, ventilation must occur much more frequently. We adjusted our ventilation rates to 3 min. intervals every 10 min. (Treatment 1), every 20 min. (Treatment 2), and every 30 min. (Treatment 3). The 8,500 BSFL density (Treatment 2) yielded consistent results, with average mature BSFL weights around 0.150-0.200 g per larva and conversion rates of +50% depending on FW type. Overcrowding at 10,000 led to uneven growth; lower densities prolonged processing. Overall averages across trials: Decomposition ~14-16 lbs out of 20 lbs; BSFL production ~4-5 lbs/tray; frass ~15% of input.
- Seasonality and Challenges: Winter conditions required minor heating adjustments to maintain 75-85°F indoors. We have also identified large moisture fluctuations along with heat build up in stacked trays, which is the commercial/practical application consisting of open stacks with 1280 cu. ft. circulation, compared to the research environment, leading to humidity swings and variations in large-scale mixing. BSFL eggs were sourced from companies focused only on egg production with reliable, proper shipping, ensuring no delays and quality. No major deviations from methods, but FW type exploration refined the approach for mixed urban waste.
Objectives are partially met: Management practices for maximization are identified preliminarily, with production values emerging (e.g., potential revenue from 4-5 lbs BSFL/tray at $2/lb = $8-10/tray; frass at 3-5 lbs/tray at $0.50/lb = $1.50-2.50/tray). Full assessment awaits Year Two data.