Composting Human Waste With Worms

Back in November I was contacted by Will Milliken, the person in charge of some composting toilets at an aquatic research center. He seemed pretty passionate about what he was doing (and excited by the results from using composting worms), so I asked about the possibility of sharing his experience here on the blog.

Here’s what he had to say:

My name is Will. I got a “real job” in 2000 as a Facilities Technician – Maintenance Mechanic at Stroud Water Research Center. It is an Aquatic Environmental Research Campus located in Avondale, Pennsylvania.

Being an environmentally conscious organization, they had installed a BioSun composting toilet system prior to my hiring date. The previous maintenance man put in the required mulch/wood chips of the time and then let it go.

When I started working here, it was brought to my attention that the composter was not properly maintained. I was instructed on how it should function. I tried to keep it aerobic by stirring it four times a year and adding a good compost made up of wood chips aged to the point of being broken down about 70%. This did not work as it would fill up to capacity every year and become anoxic (it gets a lot of input!).

I had to have the waste removed and start over every year.

In 2012, we had a new LEED Platinum building added to our campus. It included two Clivus composting systems. I was trained by the Clivus representative on how to maintain these systems. Being structurally different from the BioSun, keeping them aerobic would be easier. Part of the system, when it is fully functional, is the inclusion of vermiculture. Specifically, Red Worms (Eisenia fetida).

Before the Clivus systems were ready for the introduction of the vermiculture, I modified the BioSun to be friendlier to vermiculture also. I drilled holes in the front bulkhead to drain more liquid from the tank and installed an automatic pump out for liquid removal. I installed an automatic irrigation system to add fresh water to keep the environment from drying out. I then added a thick layer of bedding (Pine shavings).

Due to the amount of input the BioSun was ready for vermiculture before the Clivus. I purchased a pound of Red Worms from Uncle Jim’s Worm Farm. I won’t forget the feeling when they were delivered through the mail. A nice bag of wigglers.

I was excited.

I immediately added them to the BioSun. I did not know what to expect. With a large amount of input still going into this composter, I needed to stir every month. The first stirring showed clumps of happy worms!! The second or third month revealed a large ball of young worms!! They kept on multiplying and I removed some and added them into the Clivus with the same results.

The results were not totally the same for all three systems. One Clivus gets most of the attention and is working like crazy. They have even converted a good layer of the bedding. The other Clivus doesn’t get nearly the use and the worm population in that system has been slow to grow. The BioSun gets way too much attention. The women’s side of the tank has too much input and the worms do not like a lot of urine, so they do not work over there as well.

On the men’s side the worms are working over time and compost every thing, including the bedding. The men and women’s bathrooms all go into the same tank by the way. As a result of the over use, I decided to close down the system for a month to give the worms time to catch up.

In two weeks, they had moved into the entire tank and reduced the waste by more than 50%! They sure do work fast under the right conditions!

We try to encourage people to spread out their input and not go in the same place all the time. We have been adding our kitchen waste in little bits to supplement the diet of the worms. This too has had mixed results, but generally works out well. I may have to permanently close the BioSun to further modify it to be even friendlier to the worms

Time will tell.

Thanks very much to Will for sharing his experience with vermicomposting toilets! Hopefully he’ll be able to keep us posted on his progress.

If anyone else has experience with worms in composting toilets I’d love to hear about it in the comments section!

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    • ScatterBrains
    • December 10, 2014

    Man, that is….interesting. Lol, I would say that it is pretty hard to imagine having to stir…erm…compost…but having done it for the first year in Iraq I know exactly how it is. I DO NOT envy this guys job. Those look like some huge systems. He should have been on “Dirty Jobs with Mike Rowe” haha.

    • Yeti
    • December 11, 2014

    This is nice to see. I haven’t seen any operating composting toilet systems for a larger scale facility. Its fascinating to think of the huge reductions of sewage and possibilities with methane digestion for energy production at that scale.

    We have been running a small composting toilet that sees quite a bit of attention but is basically a rubbermaid container that is layered after each use with a mix of bran inoculated with homemade lactobacillus or EM-1, saw dust and wood ash from the stove.

    By the time the bin is about 3/4 full it goes to a side by side composting bin for further processing and generally has a white layer of mold on the top and little to no smell.

    After reading the guidelines set by other outhouse-style composting toilet designers I was a little worried with the length of time needed and how quickly I thought we’d be filling our side-by-side. But the worms love it, more so than our kitchen waste. 6″ of added height in material becomes 1 or 2 inches over the course of a few days and it’s loaded with black soldier fly larvae in the top few inches and may I go out on a limb and say even millions of worms below their layer.

    Anyhow, I’m happy to see someone putting red worms to use in a larger scale. I just thought I’d share my experience with red worms and their amazing ability to process human waste. I’m not sure if it makes sense or not but an inoculated bedding may speed the process for you and it wouldn’t be difficult to inoculate large amounts at a time.

    Thank you for the post,


  1. Quite fascinating! How to use in locations with poor sanitation? What is there to learn
    about living with quite nasty bacteria?

    Glad you decided to post!

    • Yeti
    • December 11, 2014

    Dave P.

    I know it likely sounds disgusting but composting human waste surprised me with its ease and lack of negative odors and chores.

    I began fermenting compost with lactobacillus as a means to compost meat, cheese, bread and other generally ill-advised compost components that are subject to putrefaction in a mixed compost pile. Look into “Bokashi” if you’re interested in doing it yourself. The idea is that lactobacillus will outcompete putrefying bacteria in an anaerobic environment, thus once fully inoculated, the substances that normally would be full of nasty bacteria are full of good bacteria allowing them to provide a great source of food for your worms. This led me to add lactobacillus to our carbon layering in the composting toilet and our results speak for themselves. I have nothing to offer in comparison as our toilet only ran the first 3 months without inoculated bedding and the pile grew quickly, however it was a newly established compost pile.

    Hope that helps. You shouldn’t ever have issues with nasty bacteria or poor sanitation with a small system and proper techniques. I would imagine a system of this size would need some interesting sanitation measures but all of which I think could be managed.

  2. Sorry Yeti. You misunderstand me. I’m wondering what medicine might learn from
    seeing how worms live (thrive?) in such a bacteria mix?

    Not disgusting at all. It’s only the last couple hundred years
    that make our current system ‘normal’.

    • James H
    • December 13, 2014

    This article caught my eye.
    I’m speaking of this based on 25-30-35 yrs of aged recall, as well as hoping I have my facts straight. So if I miss-state facts I want to pre-appoligize. Someone else out there may know more about this than I recall and maybe correct my mistakes.

    Anyway, approximately 25-35 yr ago while still living in NE Tx. there was an article printed in the local paper about the city of Tyler, Tx using Red Wigglers to compost the human waste in one of their city sewage treatment plants. The article went into detail about the kind of worms, how they operated, how much worms consumed, how small they were, how quick they multiplied, how much the city saved by using worms, etc, etc.

    At the time I was only used to larger earthworms we gathered and used for fishing, so I had a hard time visualizing how these smaller worms could do that immense job for a large city. I never forgot that very interesting article.

    Like I say, these facts are only from as I recall them. I also don’t know if Tyler, Tx is still using worms or not in their sewage treatment plant/s.

    Thought I’d mention this though. Would really like any other input from others too.
    Thanks, James

    • andreas hauch
    • December 15, 2014

    A comment on the urine issue: Where I live we have developed a system where we grow plants in our wastewater (the wastewater is drained directly into a big, underground rubbermembrane reservoir filled with any material that will hold a lot of water – in our case clamshells because we have easy acces. This reservoir is topped of with 8-10 inches of dirt, which is where we grow the plants, we have put a greenhouse on top.) . A lot of plants thrive on waterdiluted urine which contains a lot of nutrients.
    Maybe it would be an idea for you to use separation toilets that (as the name suggests) separate pee and poop. You can compost the poop, with the worms, and use the pee as we do or find some other use for it.
    Contact me on my mail if you want more info:-)

    • Mark from Kansas
    • December 16, 2014

    Thank you so much for sharing. It is articles like this that keeps me interested in vermicomposting.

    • John Duffy
    • December 16, 2014

    WOW! That’s the kind of story that gets me even more excited to see what my worms can do. Thanks for sharing your story, Will.
    What do you plan to do with the final product from these systems?

    • Alex
    • December 30, 2014

    Dave P,

    You might be interested in taking a look at a group called SOIL (, a NGO operating in Haiti that promotes the use of composting toilets to sanitation.

    You’ll probably also be interested in The Humanure Handbook (, as well, for more general information about composting toilet systems.

    • joel
    • September 16, 2016

    I wonder if the dry toilet would work with sawdust, then move it into a compost bin.

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