Commercial Black Soldier Fly (BSF) Production in 2016 | Where Are We Today?by Terry Green on 06/13/16
If someone tells you that commercial BSF production is simple, or that
this technology has been worked out, you may want to check a little
deeper into this subject. I posted a blog about two years ago addressing
the business model in farming BSF regarding long standing challenges
still needing attention (see On the Road to Commercial Production of BSFL |Sorting Out the Chaff).
This blog is a follow-up review and critique of the current state of
BSF technology relating to the growing of larvae off wastes, especially
with regard to commercial scale up of BSF production.
Enthusiasm and interest in promoting advancements in commercial BSF production is important in driving this technology forward (see, for example, Black Soldier Flies as Recyclers of Waste and Possible Livestock Feed). But I can’t help but be concerned that the science, engineering and economic components associated with this technology, also critical in advancing this technology, are lagging behind the hype surrounding it regarding its commercialization. Perhaps it is because this is an evolving technology still in its infancy, but it appears that in the rush to be the first to lay claim to successful commercialization of BSF grown off of waste, and in some instances to claim expertise in this technology, some companies, entrepreneurs and BSF enthusiasts have not spent enough time building an adequate knowledge base needed in farming BSF efficiently and economically.
Research back in the late 1970’s up through the early 2000’s placed considerable emphasis on the “potential” benefits of raising BSF larvae grown off of organic wastes (see, for example, Dried Hermetia Illucens Larvae Meal as a Supplement for Swine, Soldier fly larvae as feed in commercial fish production, Using the Black Soldier Fly, Hermetia illucens, as a Value-Added Tool for the Management of Swine Manure, Sensory Analysis of Rainbow Trout, Oncorhynchus mykiss, Fed Enriched Black Soldier Fly Prepupae, Hermetia illucens, and Fish Offal Recycling by the Black Soldier Fly Produces a Foodstuff High in Omega-3 Fatty Acids). A number of websites, social media communications and blogs since then have elaborated even further on the potential benefits of using BSF in processing and recycling organic wastes including posts on this website (see Black Soldier Fly Larvae | An Earth Friendly Feedstock?, Is Composting an Earth Friendly Method of Recycling Plant and Food Scrap Waste? and Recycling Biodegradable Wastes? | Take Your Cue from Mother Nature).
Many people unfamiliar with this technology have a need to learn more about where commercialization of BSF technology is in a practical sense relative to its potential envisioned and articulated in the late 1970’s up through the early 2000’s. In getting to the root of this question it is important to ask in practical terms what production scale should one expect, or reasonably hope to achieve in operating a viable commercial facility?
How much waste must be processed for a company to begin realizing a profit? What yield of larvae might one expect or need to produce to cover costs in operating a commercial BSF production plant? Certainly from an entrepreneur or investor perspective, for a commercial operation to reach and maintain viability the existence of a significant market for selling end product must at the very least be sufficient to offset a company’s operating costs.
There is data available that can be gleaned from a knowledge base of wastes which can be used to get a fairly good estimate of the upper limit that one might expect in terms of larval yield relative to the amount of waste processed. This information can be used to help vet a company’s claims regarding waste processed, and project with some reasonable reliability corresponding larval yields. More on this – see below!
First, bear in mind that getting an accurate picture as to where BSF technology has evolved centers on how one might evaluate or vet a company’s claims that it has developed expertise in producing BSF larvae on a commercial scale. The answer to this question is not easy to come by. Not all press releases put out by companies purporting to be experts in farming BSF, for example, hold much water. In some instances having to answer to investors putting up funds for a commercial BSF operation may also shade or hinder transparency as to how much information a company is willing to share with respect to its production numbers, and revenues, relating to its BSF operation.
Social media can also obfuscate and even stand in the way of getting an accurate picture of where things stand. Enthusiasts and proponents wanting to see progress, and anxious to affect change, perhaps even with the best intentions, nevertheless without having independently vetted the company's claims become part of an echo chamber trumpeting a company’s claims.
A big part of the task in helping move the technology forward is to sort out the hype. One antidote in taming down some of the hype is to read and listen carefully for “weasel words”. “Can” and “will” should not be misconstrued as technological milestones. After all it is not whether a particular production level “can” be achieved, or that it “will” be achieved “when” such and such happens. It is what is presently going on which matters – keep in mind that old saying, “I’m from Missouri. I’ve got to see it to believe it!”
Having a basic understanding about the physical properties of wastes, nutrient energy considerations, and the Law of Conservation of Energy (which affects larval yield), makes it possible to gain a little better insight into the validity of a company’s specific claims regarding a commercial BSF operation. So it is worth taking a moment to review how this information might be used in examining the state of this evolving technology before looking at current year 2016 company claims regarding the state of commercializing BSF production.
With regard to nutrients, and inert matter in waste, and nutrient bioconversion into insect biomass, because of the Law of conservation of Energy one can say with certainty that not all of the waste mass, or even all of the nutrient mass in the waste, ever gets bio-converted into insect biomass. This would be a violation of the Law of Conservation of Energy which in energy terms can be paraphrased as “you can’t get more than what you start with!” Some gets expended in mechanical movement and heat as the larvae grow, crawl and feed on the waste, some gets dissipated in the form of spent metabolites (lost from the waste, for example, in the form of carbon dioxide, ammonia, nitric oxide and other end products), some gets consumed by microbes also feeding and growing off of the waste, some gets left aside as inert matter, etc. Only a fraction of the waste mass ends up converted into insect biomass. On a dry weight basis, independent studies show that on average the yield of BSF prepupae harvested from food waste is about 25% (Bio-Conversion of Putrescent Waste, BSF Metrics & Yields| Scale Up Production of Black Soldier Flies). For manure, it depends upon the source of the manure but on average seems closer to about 12% (A value added manure management system using the black soldier fly, Research Summary: Black Soldier Fly Prepupae - A Compelling Alternative to Fish Meal and Fish Oil, High waste-to-biomass conversion and efficient Salmonella spp. reduction using black soldier fly for waste recycling).
The water content of waste used in farming BSF is also important in calculating larval yields. The moisture content of manure varies widely ranging around or slightly less than 50% in the case of solid manure to around 80 to 95% as a slurry (see Laboratory Analysis of Manure). The average moisture content of food scrap is around 70 to 80%, and its density is very close that that of water at around 1.06 Kg/L (see Profiles in Garbage: Food Waste, Waste Materials – Density Data ). By combining this information it is possible to calculate an approximate yield of larvae expected for a particular tonnage of waste processed (providing the moisture content and type of waste used as feedstock is known).
In the case of food waste (average moisture content of 80%), its dry weight is 20% of its total wet weight. So the upper limit in terms of larvae harvested on a dry weight basis from food waste per ton of food waste cannot in this example exceed (remember “The Law of Conservation of Energy”!) about 200 Kg per metric ton of food waste (0.2 x 1000 Kg). But wait! We already know that it is not possible to realize a 100% bioconversion of the dry weight of food waste into insect biomass. If we factor in a 25% bioconversion rate based upon prior larval yield data in the case of food waste, then for every ton of food waste (wet weight) processed, the yield of larvae would be expected to be about 50 Kg of larvae (dry weight) per ton food waste (wet weight) processed. For wet manure having a water content of 80%, it would take around 40 tons (wet weight) to yield the same tonnage of dry prepupae (assuming a larval conversion rate of ~12%).
These calculations have relevance furthermore in considering the economics of a BSF production facility. Assuming dried larvae could be sold at a price equivalent to fish meal, and taking into account that fish meal is currently selling on the US commodity market around $1500 per metric ton (see Fishmeal Monthly Price - US Dollars per Metric Ton), under present market conditions, and assuming governmental food regulatory agencies approved the use of dried larvae in animal feedstocks (they have not yet done this), a commercial facility might at best realize about $1500 in gross sales per ton of dried larvae harvested from waste.
So what does this all mean? It comes down to the following, that the basic elements in play in farming BSF on a commercial scale dictate that for a company to operate in today’s market to make any meaningful dent in offsetting fish meal as a protein substitute in animal feeds, given that it takes on average upwards of 20 tons of food waste to harvest the equivalent of one ton of dried larvae, with a return in gross sales at best of around $1500 per ton (assuming the market was in place to sell the dried larvae!), that it would not only have to operate efficiently to remain viable, but that it would also need to plan to operate with the proper heavy loading equipment designed for moving large volumes of waste in and out of the processing train of the plant facility.
OK, with this in mind, look at what's happening as of 2016 regarding commercialization of BSF production. Table 1 lists representative (but by no means all) companies in different locations around the world currently pursuing commercial production of BSF. Out of the eight companies listed, four, AgriProtein (South Africa), Enviroflight (USA), Enterrafeed (Canada) and J M Green (China), claim specific production capabilities in harvesting larvae relative to a stated quantity of waste processed. The other four recite the potential benefits of growing BSF off waste, and cite R&D capabilities regarding commercialization of BSF production facilities, but have not provided sufficient information to draw any clear picture as to where they are in advancing BSF technology in terms of actual scaled up production capacity.
It is informative in evaluating the state of commercial BSF production to examine in more detail the information provided by the four companies claiming current success in commercializing BSF production. Thus Agriprotein claims through its website in working in collaboration with The Biocycle Grow Out Facility that it gets a harvest of 1 ton of larvae for every roughly 5 tons of food waste (some mixed with human waste) processed per week (see Table 1). Enviroflight claims it is economically viable as of 2016, states that it has 17 employees, that it is producing 40 lbs of larvae grown off of pre-consumer food waste per 7 sq ft every 10 days. Its company CEO was quoted stating that his company could produce 300 tons of larvae per year per 3600 sq ft. Enterrafeed states it has 24 employees, processes 100 tons of preconsumer food waste per day from which it harvests 20 tons of larvae per day. And J M Green infers in a video it posts through the internet that it can harvest 20 tons of larvae while processing 100 tons of food waste on a daily basis.
The larval yields reported in these examples are all however exceptionally high and beyond what one might expect based on the characteristics of food waste, its average water content, and earlier measurements characterizing larval yields recovered in processing food waste as discussed above.None of the companies provides the necessary information however on the actual water content of the waste materials used in their processing sites which is essential in accurately vetting their claims.
Regarding the economics linked with labor costs, in the case of Enviroflight, Enterrafeed and JM Green, their websites show that they are all growing larvae in shallow bins filled with waste feedstock. This kind of technology can be very labor intensive and can substantially increase the cost of growing larvae.
To get an idea of the amount of manual labor involved in shallow tray technologies of this kind, bear in mind that a 5 gallon bucket of food waste weighs about 20 Kg (wet weight). To move one ton of food waste manually through what amounts essentially a “bucket brigade” operation requires the lifting and hauling of the equivalent of 50 buckets of the waste into the trays.
To process 100 tons of food waste on a daily basis amounts to hauling on a daily basis 5000 buckets of food waste! Double that labor every 10 to 14 days considering it is necessary to also empty trays in making room for more food waste needed in keeping the operation going. You can bet this amounts to a very heavy, labor costly and tedious lifting operation in moving waste back and forth from tray to tray in this type of operation.
Moreover, as noted above, based on the economics of a farming BSF and selling dried larvae as a fish meal substitute in animal feed, the scale of operation must be much larger in production output on an annual basis then has so far been claimed as in the summary of representative companies farming BSF presently listed in Table 1. One may want to question in this regard whether it is feasible to actually operate a plant facility without redesigning the operation to accommodate production using equipment and a processing train better designed for scale up operations than those employed by current companies claiming expertise in farming BSF.
Enviroflight’s claims concerning larval yields (see Table 1) are particularly remarkable and worth examining in more detail. It is possible to make a rough calculation (in the absence of detailed information provided on the company’s website) on the amount of food waste that could be loaded per a 7 square foot tray cited on their website. Based upon the density of food waste (roughly the same as water) one can calculate that the seven square foot trays used by Enviroflight, filled to a depth of four inches, would hold approximately 70 Kg of food waste (mass = calculated volume divided by food waste density). On a dry weight basis (and assuming 80% moisture content) this corresponds to 14 Kg of starting material in dry weight units. Assuming a 25% bioconversion of waste into larval biomass, and taking into account the moisture content of larvae (approx. 50%), one would expect to see a larval harvest per tray filled in this way closer to around 3 Kg (0.25 x 14 Kg) per tray, roughly one-seventh of the harvest claimed by the company.
Even if the food waste had much less water content, say 50%, the same tray filled to four inches would hold no more than approximately 35 Kg of food waste on a dry weight basis which calculates out to a larval yield of not more than approximately 9 Kg larvae dry weight per tray every 10 days, still about half the mass yield cited by the company.
The company’s claim that it completes a larval harvest every 10 days is also unexpected since the life cycle of BSF (taking into account mating, egg laying, occlusion of young larvae, and growth of young larvae up through the prepupa stage, and including then the time it then takes for pupation to emergence of an adult needed to initiate a new life cycle) is closer to 2+ weeks even under the best of circumstances. The company doesn’t account for this discrepancy in the average life cycle of BSF which bears on their projected annual larval yield.
Where does all this lead us regarding commercialization of BSF presently? I think it is safe to say that even as of 2016 commercial BSF production still has a ways to go in development before it can be said that it is fulfilling the potential envisioned by researchers back in the late 1970’s. The current technology does not appear to have yet been designed in layout form by engineering standards needed to accommodate an industrial scale production facility capable of producing the many hundreds to thousands of tons per day output required if this technology is to offset fish meal as a substitute animal feed stock. Labor input most certainly must be reduced wherever practical given that dried larvae are at best a commodity product not likely bring in a revenue stream any greater than that of fish meal.
Lastly, entrepreneurs and companies working in this field could better help advance this fledgling industry through more transparency in disclosing data on the type of waste used, its moisture content, the amount of waste used, and the corresponding yield of larvae, in a more standardized format. Additionally, it would be helpful if companies reported actual harvests averaged on an annual basis.
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