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Anybody know how much BSF larvae i can expect to yield?  RSS feed

 
dan long
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If i were to feed BSF larvae exclusively on humanure from a 2 person household, how much could I expect to yield? How many chickens and fish could i feed off of this system?

This also seemed like a really acceptable, Paul Wheaton style, "lazy bastard" method of dealing with humanure. I would raise the BSF's in the same bucket that we poop in. No emptying of the bucket until it has been worked over, deoderized and reduced by the BSF's. On that subject, how long does it take for BSF's to work over and exhaust a bucket of poop?

Most importantly, is there any reason this system wouldn't work?
 
Michael Cox
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I've not seen/read about humanure only BSF systems, but there are a few general considerations for BSF.

First; they don't really like woody materials, so covering with sawdust to keep smells down (common in compost toilets) wouldn't necessarily work well.
They like to be fed fairly consistently and the population should be able to consume everything you give it in around 24 hours. The population should expand to meet food supplied over extended periods, but your toilet probably wouldn't cope well with an influx of 20 guests for a house party, or 200 for an open air concert as we had last summer.

The BSF will not sterilise your humanure (hot composting does), although the self harvested BSF grubs should themselves be sterile - they expel their digestive systems and shed skin as they crawl off to pupate - so you will need to handle waste liquids from the bin as "blackwater" waste. You would probably want to arrange it to drain into a pit beneath a deep layer of wood chips and then plant bio accumulator plants around it for chop and drop mulching.

BSF don't like being wet so you will need to divert urine and process it separately.

Negatives aside, if you have a bin set up it could also be used to dump food scraps etc... doubling up as a composter for any other suitable waste streams. I saw one fairly neat setup that was arranged so that the BSF grubs harvested themselves directly into the chicken run by crawling up an inclined pipe then falling out. The chicken wait underneath for the next grub to fall.
 
Peter Ellis
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BSF convert something like 90 percent of food into bsf larva. The complications come in getting enough flies to lay eggs in your colony, and in keeping the population active and cycling year round. Adults are only active in warm weather, generally preferring temperatures above 80 degrees. So, if you have cold winters, your compost system stops working for that period. I have not seen any reports that bsf larvae make humanure pathogen free, so I would not want to use the product anywhere around food crops, other than fruit trees.

The BSF produce substantial liquid by-product and require a high humidity. That liquid should be treated as black water, as previously mentioned. I am a big fan of BSF but would not choose to use them for humanure processing.
 
allen lumley
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Michael Cox, It seems many people who have a BSF system like to stop handpick up road kill as a 'free lunch for the flies, I have often heard this reported, some
systems appear to be nearly smell free ditto the story on chickens waiting on Bsf to fall out of the Bucket ! Big AL !

P.S. Every time you make an original post our computer tries to find common key words that it uses to print up a listing of Similar Threads that it posts to the bottom
of this page, did you see them ? A.L.
 
dan long
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I saw some of the similar threads. It would be nice to figure out a way to make those pop up before making my post. Sometimes i worry that i am posting questions that have already been answered.

I saw an idea i REALLY liked on one of those and that was putting a toilet seat right on top of the BSF colony and then doing your thing. Means I don't even have to empty buckets!

The main objective here is not to simply find an easy way to compost the humanure, it's to obtain the BSF grubs. Humanure just has the lowest "opportunity cost" of anything else I can think of. Kitchen scraps would make better chicken feed, weeds make better chicken feed, manures and bedding make better compost (perhaps being processed in a separate BSF colony), etc. Humanure can pretty much only be used as fruit tree compost (I have some fecaphobia to overcome) either after composting or BSF composting.

I saw one suggestion that BSF don't like moisture and another that said they require it. In the system I am asking about, i would be able to pee in a separate container so that i can use it as fertilizer but there is only so much my wife will tolerate. Would it be really big deal to the BSF's if one person peed in their colony?

I might not have them emptying directly into the chicken pen since i want my chickens and guinea fowl running under the orchard. Chickens for weed control and guineas for pest control. If they are waiting at the pipe for bugs to crawl out, they wont be searching for apple maggots, etc. I would come out and feed them a few hand fulls in the morning. Same with the fish. If too many fall into the aquaponic system, then it will foul the water.

Unfortunately, my main questions hasn't been answered yet as in: how much can i expect to yield? It doesn't seem very sustainable to buy in chicken and fish feed. It takes effort to grow fish and chicken feed. But if the only thing i have to do to feed my critters is to poop in a bucket and convince my wife to do the same then that seems like a pretty good deal to me!



 
allen lumley
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Dan long : Follow these few steps and you will be an expert, and all you have to do is pass it on!

At the top right of this page between the Permies Banner and the Permies Video of the Week is the Permies Toolbox click on ->" SEARCH " and at the new page
type a 'search topic' into the 'search field' like Black Fly Soldier Larva and in the next box below your 'search field' select compost as the forum to search and clickon->
''Search'', and Bobs Your Uncle, your the expert !

While you are at the Permies Toolbox Find and clickon-> ''My Profile'' on the next page you will be prompted to enter profile and preferences for messages !

Look and your name space to the left of your post, and L@@K at mine, by posting your general location, rainfall, and climate number if known, and elevation you help
your fellow members give you good answers to specific questions and put yourself out there where your Fellow members and near neighbors can find you !

For the Good of the Crafts ! Big AL
 
Peter Ellis
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dan long wrote:

Unfortunately, my main questions hasn't been answered yet as in: how much can i expect to yield? It doesn't seem very sustainable to buy in chicken and fish feed. It takes effort to grow fish and chicken feed. But if the only thing i have to do to feed my critters is to poop in a bucket and convince my wife to do the same then that seems like a pretty good deal to me!





Dan, you have not given us much to work with in terms of projecting yield. Will your climate support an active, year round colony? That is a huge piece of estimating how much yield you may expect. You have not indicated what yield you are asking about - the colony will yield larvae, a liquid fertilizer and a small quantity of compost.

I indicated before that the larvae are very efficient at converting food into larvae, in the 90 percent range. So ten pounds of humanure could be expected to yield nine pounds of larvae. But, they are seasonal, warm weather creatures, so depending on your location, you may or may not get conversion and yield year round.

There is a difference between liquid water and high humidity. The BSF do need a high humidity, yet you need to keep the colony from drowning, so the bins have to drain.
 
Jordan Lowery
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the biggest reason i see this not working is the fact the BSF go dormant in winter months, unless you live where it never gets below 45f. even still they slow down below 60f imo.

second if its in your house? how and where are they going to reproduce, the adults need to pupate and mate within a day or two(usually in nearby trees or shrubs). and also have access to the bin to lay more eggs.

the population will grow fast, faster than you think. and will eat more than you think. i had a 15 gallon system and threw in a dead chicken. gone in 12 hours. everything.

 
dan long
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Peter Ellis wrote:
I indicated before that the larvae are very efficient at converting food into larvae, in the 90 percent range. So ten pounds of humanure could be expected to yield nine pounds of larvae. But, they are seasonal, warm weather creatures, so depending on your location, you may or may not get conversion and yield year round.



Thanks for the ratio! That gives me a much better idea of what i should expect to get. 9 pounds of larvae from 10 pounds of poop.

BTW, ill be in Souther California. More than hot enough to keep them going year round!
 
Abe Connally
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I indicated before that the larvae are very efficient at converting food into larvae, in the 90 percent range. So ten pounds of humanure could be expected to yield nine pounds of larvae.


BSF Feed Conversion depends on the nutrition of the manure. They are not 90% efficient in converting manure to larvae weight. They will, however, reduce the weight of the the manure by 90%. But, their yield of live weight depends on what manure they are eating.

BSFL FCR:
BSFL on chicken manure: 3
BSFL on pig manure: 4.8 (I've seen this confirmed by a few sources)
BSFL on cattle manure: 7.8
BSFL data from "From organic waste to biodiesel: Black soldier fly, Hermetia illucens, makes it feasible"

Human manure will be most similar to pig manure. So, for every 4.8 pounds of human manure, you can expect to yield one pound of BSF larvae.
 
Peter Ellis
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Thanks for the correction, Abe. I had read, some time ago, about bsf reducing the compost material by ninety percent and crossed my wires to assume that meant ninety percent conversion.

Thank you for straightening that out.
 
Abe Connally
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Location: Chihuahua Desert
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Peter Ellis wrote:Thanks for the correction, Abe. I had read, some time ago, about bsf reducing the compost material by ninety percent and crossed my wires to assume that meant ninety percent conversion.

Thank you for straightening that out.


I know this is an old thread (1 year), but found some more research on this topic, so figured i would add it here:
http://onlinelibrary.wiley.com/doi/10.1111/tmi.12228/pdf

objectives To determine the capacity of black soldier fly larvae (BSFL) (Hermetia illucens) to convert fresh human faeces into larval biomass under different feeding regimes, and to determine how effective BSFL are as a means of human faecal waste management.

methods Black soldier fly larvae were fed fresh human faeces. The frequency of feeding, number of larvae and feeding ratio were altered to determine their effects on larval growth, prepupal weight, waste reduction, bioconversion and feed conversion rate (FCR).

results The larvae that were fed a single lump amount of faeces developed into significantly larger larvae and prepupae than those fed incrementally every 2 days; however, the development into pre- pupae took longer. The highest waste reduction was found in the group containing the most larvae, with no difference between feeding regimes. At an estimated 90% pupation rate, the highest bioconversion (16–22%) and lowest, most efficient FCR (2.0–3.3) occurred in groups that contained 10 and 100 larvae, when fed both the lump amount and incremental regime.

conclusion The prepupal weight, bioconversion and FCR results surpass those from previous studies into BSFL management of swine, chicken manure and municipal organic waste. This suggests that the use of BSFL could provide a solution to the health problems associated with poor sanitation and inadequate human waste management in developing countries.



So, feeding Black Soldier Fly Larvae fresh human faeces resulted in FCR of 2.0–3.3, which is better than a lot of insects, and better than BSFL on a lot of manures.

An average human excretes .5 kg of faeces per day, which could make 165-250 grams (~1/2 lb) of BSF daily! That's enough for several chickens.

Considering chickens need 5% of their body weight/day, and you'd need probably 2-3 times the weight of BSFL in grain, you could feed approximately 35 lbs of chickens, which is probably around 5 chickens per adult human.
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