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.
Alder Burns wrote:I did this very thing two consecutive summers in GA, and since then have done it also with dog and chicken manures. The BSF love it all. I'm astounded by the vile things they relish. Even deadly poisonous Amanita mushrooms from the forest.....converted into chicken feed! Moldy stuff of whatever sort (which will put chickens off of laying, quick, if fed directly). Road kill and slaughter trash. Of course you will want to locate the bin at a distance, since there may be some smell if you feed stuff like that; though this is less so with a vigorous colony. The residue left over I then put through my regular humanure protocol. But I have a suspicion, and intend this year to make trial of it, that the residue left from BSF can then go on to raise compost earthworms, thus multiplying the yields still further!
Peter Ellis wrote:What I am curious about is any research into whether the BSFL have any effect on levels of pathogens in the before and after products.
Peter Ellis wrote:Considering that they are almost invariably being fed waste products (and I mean stuff with really minimal potential further use), I do not really see the point in studying the efficienct of feed conversion. That is a meaningful value when the feed has a cost associated with it. Not so much here.
Peter Ellis wrote:
I see the importance of how much they reduce the mass of their feed source. If they reduce a volume of waste material by ninety percent, that is a huge impact in terms of what you have left to dispose of. Considering that you can, in effect, run a figure eight pattern that runs pig poop into soldier flies into chickens into chicken poop into soldier flies into pigs and back to the beginning, it isn't an infinite motion machine, but it is a sort of regressive processing system that pulls every possible erg of energy... and yes, you would need to be feeding more into the system.
Peter Ellis wrote:
In tropical environments where biogas production is highly viable, there may be some real balancing to do to determine which option provides the best return in a given situation.
Peter Ellis wrote:I continue to have some concern as to how effective BSFL are at reducing bacterial populations in manure. Not so much in terms of the larvae carrying pathogens to the chickens that eat them - and possibly on to us in eggs or meat- as in the remaining waste product when the BSFL are finished eating.
That remaining product needs to be dealt with in a healthy manner. I am hopeful that there is a straightforward method for reliably eliminating pathogens that does not require substantial energy inputs (heat sterilization would not be a first choice in my view). Would vermicomposting do it? I don't know, but would be very interested in information along this line.
Peter Ellis wrote:
It would be pretty amazing if you could dispose of humanure in a highly efficient, productive and sanitary manner that not only produced a valuable product but also kept housefly populations down and so reduced disease risks even more.
Alder Burns wrote:From what I have read and observed in my own system, houseflies and BSF are competitors for similar resources, and when both are present, the BSF dominate and, in a vigorous colony, prevent housefly larvae from establishing at all. Neither are houseflies attracted to the residue remaining when BSF finish with it. So directing dangerous manures and other farm wastes through BSF is actually an improvement over disposal methods open to housefly infestation. On our current small homestead, when I see housefly numbers on the rise, it's usually an indication that I need to go pick up dog poo! They don't get into the humanure buckets, which go either to the BSF first or directly into a screened compost pile.
Alder Burns wrote:
I have found through long experience (doing humanure on five different homesteads and farms since 1985) that the recycling of urine and humanure stops a very significant nutrient loss, and, over time, their use is a major contributor towards ratcheting up yield on the small homestead.
William Bronson wrote: I have a question about stink.
I have accidently raised bsf in a bad composting situation.
The stink was incredible,unlike anything I have ever encountered, even as a plumber.
I am thinking that it might have been the build up of leachate, most sources say they stink less?