double chamber composting toilet

hey folks!

i have built (pics to follow!) a doublke chsmber compopsting toilet and its going, for the most part, very well.

one problem that has raised its head is that i am getting little critters in there! i dont have a glass bottle fly trap... could this be the issuse

is there a homemade spray that i could use

thanks

hey stan... i am looking forward to the pics.

could you use a UV-anti-fly-lamp with a cable and let it hang into the chamber from time to time?

could you retrofit a normal fly trap? if you use netting on top, the flytrap could act as ventillation, too.

a huge amount of dry cover material would mitigate problems a bit for some time, if the vault-space permits.


good luck

Thanks for the reply to bias 👍

Yea the UV lamp would do the job but wouldn't solve it... I'd would like to solve it.... not the space for lots of dry material

Suppose there is a gap they are getting through 😠

Il try tonite to get the the pics up 👍

Starting the second double chamber compost toilet next week which will be a stand alone structure. The first one is a extension to my cabin

We've been using double chamber compost toilets at our school for about 15 years. I'm sorry to report I don't have any great advice for your fly problem. Not because we tried hard and didn't succeed, but because we didn't really try very hard.

-- We did try the fly trap bottle thingie, putting the bottles on the upper outside of the manure chamber door, where they get direct sunlight for a few hours a day. They did collect flies, and did make a difference, but they didn't eliminate flies completely. The manure chamber doors have deformed over time and no longer close tight, so we don't even bother with the fly traps anymore. Anyway, the traps really bothered the Ladakhi Buddhists, the majority here, who have been preached to since childhood that you should never kill any living creature, even a fly, and they seem to take it as "especially not a fly."

-- Cover material and training the users to use it regularly makes the biggest difference, I think. We often use sawdust and wood shavings from the local lumberyards, and (whole) autumn leaves, but both of these are poor at preventing flies. When we're out of those, we use garden soil, and frankly that works better at reducing flies. The carbonaceous materials do well at controlling smell and I think they make better and lighter compost, which is important too, but the larger wood shavings and whole leaves allow flies access to the latest poop. Fine sawdust would be better but we can't get much.

-- Our upstairs user rooms don't have a roof at all, which means it's not oppressively unpleasant even if there are some flies, and there is rarely an oppressive smell.

-- Our manure chambers are very big, 3 x 8 feet (1 x 2.5 m), which is great for handing the large numbers of people we have here (holding enough for a whole year on each side), and wide enough to be convenient to empty. We average about 20 resident users per user-room, year round, and almost nobody pees elsewhere. We have two holes over each manure chamber (covering off the two holes over this year's unused chamber that is standing to compost). But I've also thought of a design, for a smaller population, where you'd have a much narrower manure chamber, so that when you throw the cover material down the hole after use, it forms a thick layer over the recent contribution, instead of falling far away to the sides. That might help with the fly problem, too. I think.

-- Aside from the bottle-light trap, which simply hopes that flies go in but can't figure out how to get out, there is the sticky-trap tactic. Nowadays, instead of the hanging spiral fly strips we used to use in the US, you can get "clear window fly traps." I use these in my residential quarters, and they are very effective, and much easier to handle than the coils. They are about 2 x 6 inches of clear plastic, sticky on one side with a narrow strip on the other side to stick to the glass. Especially in cold weather when the window is sunny and warm, the flies bump up against the window until they get stuck.

-- I've been thinking that introducing compost worms to the manure chamber might help, since maybe they would fill the ecological niche that the flies are using, without an annoying adult phase. But my colleagues are skeptical about that suggestion because of the fear of killing a bug. They say nobody will be willing to empty the chambers if the manure is full of worms. I said I heard that when we're not using the chamber for a year, the worms will migrate through holes in the wall to the fresh chamber. So this summer we got some worms and threw them in, but I won't have much to report for another year until we empty it. It's in the boy's toilet block so I haven't seen for myself if it reduced flies.

-- Oh, I forgot, we introduced urinals and a big ol' tank for urine this summer in the boys block, but I haven't asked if that has reduced flies. The tank gets drained into the irrigation canal when the trees near the boy's toilet block are watered. Also I'm curious when we remove the manure after two years, if the cover materials have decomposed as usual or instead enclose desiccated turds. In this arid climate, that seems a possible risk to me.

hey rebecca,
thank you for your post.

worms should be a good idea. what kind of walls do you have between the chambers? worms will go where the food ("food" defined from THEIR point of view ) is.

Rebecca Norman wrote:Also I'm curious when we remove the manure after two years, if the cover materials have decomposed as usual or instead enclose desiccated turds. In this arid climate, that seems a possible risk to me.

i think, it would help to wet the un-used chamber from time to time. there will not be much composting going on without moisture. some urine in there would be helpfull to break down the carbs. worms would need moistures, too.
maybe it makes sense to add greens (leaves, grass, composting material)for the last months/weeks of the use of that chamber. when you see that you would have enoigh room left.


concerning flies, most important thing would be to make sure that no new flies can enter from the outside.

Tobias Ber wrote:
worms should be a good idea. what kind of walls do you have between the chambers? worms will go where the food ("food" defined from THEIR point of view ) is.

Good question. The walls between the chambers are fairly solid, so perhaps for the tactic of worm migration to work, we'd have to make sure there are several holes between the chambers. I think drystone wall would be an excellent wall for that purpose. Some of our chambers have concrete bricks, not well plastered, so I hope they have enough holes through for the worms.

I have noticed that each year is different for the  number of flies and gnats that are an issue.  It's mostly in the summer, not all year.    

One important thing I've found is to store your cover material in a solid shed, even one that gets hot during the day, so no insects can get into it, or if any are in it already, they will leave.   It seems like where I am gnats hatch in mulch and mowed weeds, which is what I use for cover material, so keeping them away from it in the first place makes a big difference.

I use sticky fly strips in the room to keep as many insects as possible from leaving the room.  Be sure no small birds can get anywhere near the sticky strips, they get stuck and it's really bad.

I grow strongly scented herbs on pots outside the back door, pineapple mint (which so far no critter has eaten, not even the packrats) peppermint, spearmint, sages, cut these frequently and layer them in every time.

We store kitchen scraps in a large yogurt container with a tight lid, and take out kitchen food scraps every day so they don't accumulate and attract gnats.  There are no plants or seed trays outside the door where gnats can hatch and find their way in.

We've gotten rid of house plants, which may seem like a bad thing, but the gnat issue has practically disappeared.

It finally got to the point where I put a sub container inside the composting toilet and remove it once a week, compost it outside.   This may only need to be done in the summer when conditions are the worst, but I honestly like handling it in smaller amounts.  It gets out into the garden faster this way, too.  There's all kinds of room to turn it, there's no spilled bits on the floor to clean up, it's a tidy way to handle it.