Compost Toilets

What skills to learn, what tools to get
Jin+Guice
Posts: 758
Joined: Sat Jun 30, 2018 8:15 am

Re: Compost Toilets

Post by Jin+Guice »

We made the toilet and we've been shitting in buckets outside for a few months now. Honestly I feel like I'm losing anytime I have to shit inside. I usually start my morning by yelling about how shitting inside is for fucking pussies and how houses are for the weak.

Here's how it works: We've got a bucket with a lid that we put a heavy rock on top of when it's not in use. We've got two small pieces of wood and some cinderblocks next to/ over the bucket and we've got a toilet seat we put on when we're going to use it. We've got toilet paper in an old plastic coffee container. We don't leave it up all the time because it's outside and we don't want the neighbors to get suspicious. Once we shit in it, we cover the shit with sawdust we get from a local sawmill. When the bucket is full we let it sit for a few days then add it to a second contained compost toilet we made out of 4 pallets. We then cover the shit with leaves. We also throw about half of our food waste in the bucket and half in the other compost pile. We've decided to not use the humanure on food (even though it's supposed to be safe). We don't want to gross someone out after they've already eaten food from the garden when they find out about our hippie bullshit. The other dude is being slightly less careful with making sure the shit buckets are consistently and only shit buckets than I'd like (we do clean them out after each use), so I'll let you guys know if we die or get some kind of horrible disease.

reepicheep
Posts: 364
Joined: Mon Dec 29, 2014 7:45 am

Re: Compost Toilets

Post by reepicheep »

https://www.homebiogas.com/Products/HomeBiogas_Toilet

I bought this and plan to use it in my tiny house, with a greenhouse around it. I'm running pipes out of my wood stove through the back wall and through the green house to try to keep the whole thing warm enough in the winter. I assume I will be using the wood stove when it's cold.

At my community we also have outdoor composting toilets, as well as a failing septic system. The waste from the toilets goes into 55 gallon drum barrels, which we let sit for two years. They get stirred every six months or so to aerate. I don't know if that's necessary. Every spring we open up a lot and put the resulting dirt around fruit trees, which we then cover with mulch.

So far nobody has died. Moving 55 gallon drum barrels full of human waste is not a popular job and doesn't get done with the kind of regularity required of a community of our size, which is why I'm going for the methane biodigester for my house.

EMJ
Posts: 349
Joined: Sat Nov 20, 2010 6:37 pm

Re: Compost Toilets

Post by EMJ »

A styrofoam toilet seat really makes the outhouse more pleasant if you are in a cool/cold climate.

white belt
Posts: 278
Joined: Sat May 21, 2011 12:15 am

Re: Compost Toilets

Post by white belt »

@reepicheep

Cool stuff, let me know how you like it. I was only able to find one video on YouTube talking about the Biogas2 with the toilet option. I think that would be the option I would go for in my hypothetical tiny house build as well.

I think the greenhouse is a good idea and I’ve also toyed around with using the biogas as passive heat inside a green house with other plants. I’ll be curious if you can keep it going through winter with your strategy.

white belt
Posts: 278
Joined: Sat May 21, 2011 12:15 am

Re: Compost Toilets

Post by white belt »

For the compost toilet pros out there, what do you do with the pee bucket once it’s full? From my research I’ve come upon this as the standard method:

-dilute it with 10 parts water to 1 part urine and dump it on some perennials or non-edible plants the same day (one person would fill up a 5 gallon bucket each day with this method)

This has one glaring issue and it’s that urine can spread antibiotic-resistant DNA into the soil. It seems that storing the urine for a couple months will mitigate that issue, but I can’t get access to the full article to see if they watered down the urine as well: https://news.engin.umich.edu/2020/01/ag ... ertilizer/

From a practical perspective, as a male living in a rental property, I think diverting my urine and using it for fertilizer is an easier first step for reducing water consumption and closing some of my waste loops.

Edit: Maybe this antibiotic-resistant bacteria is only a concern if the urine is coming from a person with a UTI? I’m unsure because according to WHO it seems urine is suitable to be used for fertilization of household vegetables without sanitization. This guide seems to go into more detail: http://richearthinstitute.org/wp-conten ... ual_05.pdf

reepicheep
Posts: 364
Joined: Mon Dec 29, 2014 7:45 am

Re: Compost Toilets

Post by reepicheep »

We use wood chips instead of sawdust and actually found that if we didn't pee in it the mixture didn't sufficiently decompose over the 2 years we let the barrels sit.

Also, yes, hoping to at least have some space for starts in the greenhouse. So a mixture of heat sources for that.

I *think* the worst that can happen is that the waste doesn't fully decompose when it's cold. I'm. Uncertain how smelly that would be, given that the waste is contained in two bags. I'm a household of one, so at least the results of a failed experiment aren't going to mean that multiple people can't properly dispose of their waste. And there are other backups.

white belt
Posts: 278
Joined: Sat May 21, 2011 12:15 am

Re: Compost Toilets

Post by white belt »

Well after reading more into it last night, I’ve ordered the supplies to construct my own urine diverter system to put next to my conventional toilet. Basically it’s a funnel with a lid, some 1/2 inch irrigation tubing, and a 5 gallon jug. In theory, the lid on the funnel will eliminate odors when I’m not using the system and make things a little less icky for guests using my bathroom. I used this build as inspiration and modified to fit my needs: https://youtu.be/s4wTZgZ2T8k

My plan right now is fill the jug for about a week without diluting. That should get it half full and then I will seal and store it for a week to sanitize it. After that, I can dilute it and use it as fertilizer. Given that it is winter time, I will just be pouring it around trees and bushes outside. In the spring I’d like to use it on my vegetable garden, but I am a bit concerned about sodium accumulation in large container hugelkulture beds. I do live in a very humid and rainy climate which might help to wash away excess salt (not sure if sodium will leach out through drainage holes).

I will have way more fertilizer than I can utilize on my small garden beds (5+ gallons per week when diluted 1:1), so most of it will just go back into nature. Also, I will be saving ~60 gallons of water per week from not having to flush when I pee. With my worm composting system for microgreens and urine fertilizer for outdoor crops, I may never have to purchase fertilizer again!

Further reading: https://www.susana.org/_resources/docum ... 4-web1.pdf

white belt
Posts: 278
Joined: Sat May 21, 2011 12:15 am

Re: Compost Toilets

Post by white belt »

I completed my urine capture prototype. I may have over-engineered things a bit:

Image
Image

That’s a 5 gallon HDPE jug, funnel with lid, 5/8” ID Vinyl tubing, hose clamp, and irrigation tubing connector. Originally I was going to use irrigation tubing, but it was way too rigid so I opted for the vinyl tubing which has more flexibility. The yellow funnel color was purely coincidental.

Everything fits neatly under my sink so as to not scare guests. My conventional toilet is still fully operational and available for guests and #2. I’m obviously male, so a design to accommodate females may require a larger funnel (although the funnel is already quite large) and a different tube length. I opted for this type of jug over a traditional 5 gallon bucket because it is easier to handle liquids. I have a 2nd identical bucket that I can swap out when the first one gets halfway full. That should allow me to store a bucket for a week or 2 before applying it as fertilizer.

The only thing I still need to make is a sleeve to cover the outside of the jug (I’m trying to figure out where they sourced the cover in the video I linked above). This is mostly aesthetic so I don’t have to see my pee in the translucent bucket, but also so that I draw much less attention to myself when I’m applying the diluted fertilizer to my garden.

7Wannabe5
Posts: 6833
Joined: Fri Oct 18, 2013 9:03 am

Re: Compost Toilets

Post by 7Wannabe5 »

I don’t think the funnel needs to be larger for female use if it is somewhat flexible. I made a device for myself for hiking and it is the cut off top of a plastic cranberry juice bottle with duct tape applied to the rough edges. It is held in place with the spout with the spout lid on. If the funnel can be pressed snug then it will catch side spray that might otherwise wind up dribbling down a leg.

When I stayed with a friend who only had one functional bathroom which was in his bedroom, I used a plastic watering can at night and just dumped it by his shrubbery in the morning.

Alphaville
Posts: 2432
Joined: Thu Oct 03, 2019 10:50 am
Location: Quarantined

Re: Compost Toilets

Post by Alphaville »

i grew up with a classic chamber pot under the bed till the age of 7 or so

looked sorta like this
https://img1.etsystatic.com/123/1/88119 ... 5_3hj8.jpg

idk why these aren't more popular

white belt
Posts: 278
Joined: Sat May 21, 2011 12:15 am

Re: Compost Toilets

Post by white belt »

@7Wannabe5

It may be usable by both sexes then because the tubing is quite flexible and the funnel is large. I don’t have a female crazy enough to test it at the moment.

@Alphaville

My guess is most people don’t like thinking about their own pee and poop. I think there have been some studies of interventions to implement bidets or compost toilets in public places which always face heavy resistance to adoption, even after extensive education/PR campaigns. I mean even basic routine changes to anything related to a toilet are a pretty traumatic event (e.g. a westerner’s first encounter with a squat toilet, toilet paper wars during COVID, etc). In the military you get used to such things really fast when the options are to pee in a plastic water bottle or pee in your pants. Pee bottles are so common during operations that they have become somewhat of a meme. In patrol bases you’d have 40 people pooping in a slit trench that is pretty much within 15m of everyone due to the fact it has to be inside a small security perimeter.

Alphaville
Posts: 2432
Joined: Thu Oct 03, 2019 10:50 am
Location: Quarantined

Re: Compost Toilets

Post by Alphaville »

yeah i have no urine phobia of any sort. feces, only those that belong to strangers :lol:

in my cabin before septic we'd just use a bucket

i think that a chamber pot *with a lid* fits the bill under any circumstance.

plus yeah as a child i'd fill mine with solids on occasion :lol:

the beauty of the enameled ones is they rinse very easily.

white belt
Posts: 278
Joined: Sat May 21, 2011 12:15 am

Re: Compost Toilets

Post by white belt »

I’ve been using the urine capture system for a couple days and it’s working great so far. Easy to use, no leaks, no odors. In a week’s time the jug will be half full and I will swap it out for my empty one. As I mentioned, I live in an apartment so this is something that’s easy to implement without any infrastructure changes.

The natural next step in this progression is to figure out what to do with feces. I haven’t yet found a perfect solution for an apartment. A traditional compost toilet system like what OP implemented is a bit challenging in my studio due to space restrictions. Additionally, urine is way more nutrient dense than feces, so I’m already making use of most of the fertilizer with relatively minimal processing effort and infrastructure. Compost toilet would also require me to source carbon material from somewhere and use water to clean out the buckets after I add them to the compost pile once a week. Not sure if it’s worth the effort over just using the conventional flush toilet.

As I mentioned earlier in the thread, I do like the option of using feces in a biogas digester. If my estimates are right then I should be able to yield 5 min a day of cooking fuel from just my own feces, provided the digester is over 55 degrees (summer months). The problem is I can’t install a pump marine toilet like what comes with the Homebiogas 2 in rented housing, even if I could find a suitable place outside to put the digester.

white belt
Posts: 278
Joined: Sat May 21, 2011 12:15 am

Re: Compost Toilets

Post by white belt »

Ok I have an idea (which after further research appears to have been done before). It’s a spin on the simple bucket compost design. Instead of emptying the bucket with poop and cover material into a traditional compost pile, it goes into a bin with Black Soldier Fly larvae. They eat the humanure along with quail manure and grow, eventually harvesting themselves by climbing into the collection bin. I then boil these harvested larvae to kill pathogens (not sure if pathogens can pass through 2x species' digestive systems, but just to be safe) and mix with seed/grain to get 20% protein feed for quail. Quail then use this protein to make eggs I eat. The system would work for any kind of poultry or fish that eat bugs.

The remains of the humanure after BSF composting would just go into a regular humanure compost pile. Odors shouldn’t be an issue with the humanure covered in sawdust and with how fast the BSF process waste.

This system would only work outdoors from spring to fall because BSF breed in warmer temperatures. If I seed with live larvae at the beginning of spring then that should help to attract wild BSF to continue laying eggs. Once the population is established they can outcompete any pests. In winter, I’d just compost the humanure in typical sealed off barrels, perhaps then feeding to BSF in warmer months. BSF larvae surplus can be frozen in warmer months to feed to livestock during winter months.

Here’s an example from Kenya of a similar system on a commercial scale: https://www.reuters.com/article/us-keny ... SKCN1TI1BN

Someone on Permies talking about using such a system for 2 years in SE USA: https://permies.com/t/26669/black-soldi ... post-human

Study showing BSF larvae can grow while eating only humanure: https://onlinelibrary.wiley.com/doi/ful ... /tmi.12228

That's the best I can come up with for closing loops at the moment.

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