Can you use Black Soldier Fly (BSF) indoors for toilet??

hey! this is an odd question and i understand that it may not be practical but the thought experiment is rolling around the back of my brain and i was hoping to get the opinion of someone who knows more about the topic than i do.

so i have heard of folks using BSF in their summertime outdoor toilet systems to keep waste from piling up at festivals and such, or i saw one guy was transferring their own waste to their outdoor bin, but what really intrigues me is the idea of managing a fully indoor bin where human waste is deposited directly into the bin. i understand that you would have to manage a rotating breeding population of adults in some sort of enclosure indoors as well to continuously repopulate the bin in the winter, or have a gateway to the outdoors for adults to access the pod and lay eggs but it still seems like the reward of not having to empty your composting toilet every week and getting a small harvest of pupae all year round from a waste stream that otherwise doesn’t really get utilized might be worth the effort.

is there some reason that this system would definitely not work? the indoor temperature of the house could be kept 70+ degrees and the bin would create a bit of its own warmth to my understanding, and i have seen people make small breeding enclosures out of mesh to collect eggs indoors. i would assume a small pod like those commercially available that are fully enclosed and have a ramp for harvesting grubs could potentially handle the solid waste from four people, and you would need to devise a urine diverter much like our current compost toilet has. inquiring minds want to know, and folks who have to empty their compost toilets weekly want to find an alternative.  

I think this is feasible, but I would look at it like a two part system. One breeding "egg gathering" containment, and then the actual larvae feeding feces container. Use banded together corrugated cardboard to continue to gather eggs and place them in the bin, harvest a handful of larvae after they pupate and put them into the "egg gathering" area to hatch, breed, and make more eggs. With how much they eat, I would guess that a 30 gallon tote would be about the size needed for 4 people, but you may have to do a little reading up on that and adjust. I know when my bins are full and rocking in the summer time, they can really go through some material. One thing to try to figure out would be the smell though. BSF larvae don't really care for sawdust or other woody materials that are traditionally used to cover and dry out feces. Maybe some dried coffee grounds would act similar and also help cover the stench, but that would also contribute to your food load on the maggots. Depending on size that could be good or bad, but it would be something most would need to source in that quantity. If you give it a go, keep us informed!

that’s all great info and i was actually thinking about coffee grounds as a substrate/cover. the smell is something i wondered about because i haven’t raised the BSF before and i have no idea how they smell. i thought about using a pod like this https://www.protapodusa.com/biopod-plus.html but it sounds like this would be quite a bit too small so i am curious what other kind of containment might work well and how to make the system self harvesting. and how to arrange the seat and urine diversion. i guess my main question for those in the know would be 1. would this be downright too stinky to attempt indoors? 2. could you keep a breeding population in a mesh enclosure in the house and how hard would that be? 3. would normal house temps be high enough to keep the colony happy? 4. if it is a year round system how do you clean out their waste periodically without destroying the grubs? maybe use a traditional composting toilet for a period of time and keep some grubs in a cool place to eventually repopulate and let the grubs cycle out of the system without replacing them with eggs and then empty and refresh?  i will definitely document it if we decide to try this out!!

Seems feasible since they could eat a small bit, but you’d want to have the ramp where the larvae crawl out likely outside or something.  This makes good chicken feed opportunity if you catch them, or just let them out to make more bsf.  

What makes this possible is that they hate humans, and so might not be an issue if it’s built right….. just could see one flying up at a very bad time

A bright idea that could be actualized,  best of luck.

For this effort.  

"So i am curious what other kind of containment might work well and how to make the system self harvesting. and how to arrange the seat and urine diversion. i guess my main question for those
in the know would be 1. would this be downright too stinky to attempt indoors? ......."

...I think you might use a compost bucket system with largish (1/2 inch?)  holes underneath (similar to Paul Wheaton black fly larva feeder for chickens).
For our chickens, that was close to self feeding.  Ask others please about size of drilled holes

My bins don't smell bad, but they are outside and i will put anything in them. Chicken carcasses, squirrel and deer offal, spoiled meat, etc. If you wanted to give it a try indoors, just get a geriatric potty seat that would normally sit over a toilet, and put a tote or bin in your bathroom and give it a shot. You'll know soon how bad the smell is. As for harvesting, this will depend heavily on where your bin is located within the house, but in general, mine are self harvesting. They climb up a ramp in the bin and ride down a shoot made of 1 1/2" PVC pipe to a collection bucket. You could do this easily if your bin is at least 18 inches tall like a normal Rubbermaid tote, just make your ramp up to the top of it, and then the shoot would run to a collecting container at floor level. They can't climb very well as long as the bin is dry. I think normal house temps would be just fine, as long as you aren't keeping it like an ice box. While mid 80's is optimal temperature, they will breed down to 70 (or so says the mighty google). As far as cleanout goes, I would just take a portion of the bin when it gets full and remove it to your compost pile. If some grubs come along for the ride, so be it. Spread the remainder out in the bin, and keep going.

Apologies, I should have said 'maggot bucket' from P Wheaton's comments

curious if OP has tried anything since posting earlier in the year! this is my second warm season having a successful bsfl bin setup outdoors -  in the interest of hopefully helpful additional data:
-i didn't introduce any eggs, just lured native adults in with stinky food waste
-they're in a 27 gallon black-and-yellow tote with like... 1/2"x2" adult access slits near the tops of the tote walls, and ~1/8" drainage holes along the bottom edge of the tote
-they go through as much food waste as my partner and i can generate - we're not always cooking from scratch by any means, but we do often purge stuff out of the fridge, or pick up roadkill, etc - and the 27gal bin has handled all of that fine. we added the better part of a deer last year and the larvae Loved it
-the bin is in our chicken coop, and we let the chickens scratch around in it during the day, to the point that they've stopped eating their pellets bc they're getting so much from the bsfl.

relevant to your questions -
larva collection - plenty of setups/videos online of peoples' ramps leading to detachable containers. just note that the larva need a certain amount of humidity to travel uphill successfully. ours migrate out of the tote (with no ramp) right up the vertical walls on super humid/stormy days when there's condensation lining the tote walls.

1. re: smell: it's still gonna smell like poop, for sure, bc you'll be adding fresh material so actively. def worth experimenting with smell-nullifying additions that compost in nicely/break down effectively.

2. re: mesh enclosure for adults: i've def seen enclosures like that when searching on youtube for other bsfl setups - people in other countries don't seem to be afraid of that. i would personally wanna figure out how to direct them out a lil window tunnel, but if you wanna just let them breed and die in there, you'd just need some kind of collection mechanism for the bottom, and to consider the noise/vibes of having hundreds of adults flying around confused about what a net is. (if i had to dream this up quickly, i'd play with those rectangular/cube-ish shaped mosquito nets meant to cover a cot, and stockings as a flexible but breathable passageway from the bin to the mesh area, and just tape shi together and see what happens)

3. re: temperature: ours definitely lasted well beyond temps staying under 70 degrees. they do generate a fair bit of their own heat. i would expect a basement environment to be adequate ambient temperature in complement to their own heat.

4. re: drainage/waste removal: if your bin can sit in some kind of collection pan, or be raised enough to have tubes/drain pipes connected to your drain holes, you could collect that liquid and treat it like a concentrated compost tea i would guess. this is also in response to 'cleaning out their waste' - as long as some moisture is going in, i'd expect the waste to drain out the holes adequately not to be an issue, but that's speculation. i do a fair bit of turning on my bin, since i can just remove the whole lid, so idk how much that contributes to low levels of waste material.

i haven't personally read from other people putting human waste in with their bsfl yet, but my question would be - how much do they Like eating human poop? bc there's definitely materials in our bin that haven't broken down after months and months. so there may be an extent to which it depends on their appetite, and whether you include other materials to balance out their interest to get a good rate of consumption. when our bin is getting low (around half full) i start chucking in handfuls of weeds pulled from the garden and mix those in. for an experimental first round/season, i would personally just want to make it easy to swap the bin out in case it just needs to go into a larger pile and get refreshed/cleaned/whatever. not a big deal to have to scoop some larvae out of there to chuck into a fresh bin after.

best of luck! so curious to hear results.

Julia Mason wrote:hey! this is an odd question and i understand that it may not be practical but the thought experiment is rolling around the back of my brain and i was hoping to get the opinion of someone who knows more about the topic than i do.

so i have heard of folks using BSF in their summertime outdoor toilet systems to keep waste from piling up at festivals and such, or i saw one guy was transferring their own waste to their outdoor bin, but what really intrigues me is the idea of managing a fully indoor bin where human waste is deposited directly into the bin. i understand that you would have to manage a rotating breeding population of adults in some sort of enclosure indoors as well to continuously repopulate the bin in the winter, or have a gateway to the outdoors for adults to access the pod and lay eggs but it still seems like the reward of not having to empty your composting toilet every week and getting a small harvest of pupae all year round from a waste stream that otherwise doesn’t really get utilized might be worth the effort.

is there some reason that this system would definitely not work? the indoor temperature of the house could be kept 70+ degrees and the bin would create a bit of its own warmth to my understanding, and i have seen people make small breeding enclosures out of mesh to collect eggs indoors. i would assume a small pod like those commercially available that are fully enclosed and have a ramp for harvesting grubs could potentially handle the solid waste from four people, and you would need to devise a urine diverter much like our current compost toilet has. inquiring minds want to know, and folks who have to empty their compost toilets weekly want to find an alternative.  

This is a fascinating thought experiment. I can see the appeal of turning a waste stream into something useful, but human waste is a very different challenge than the food scraps BSF are usually raised on. Pathogens, medications, parasites, and the need for proper sanitation would make indoor use much more complicated.

The idea is creative, but the management requirements would likely outweigh the benefits for most people. A well designed composting toilet or other approved system is probably a safer and simpler solution. Still, it’s an interesting concept and I’d be curious to see research into larger scale systems designed specifically for human waste.