Earth Closets to Eco-Thrones

An innovative history of composting toilets and their growing impact

Written by Avery Pope, TE Board Member

History

The concept of a compost toilet can be traced back to the 1800’s when Reverend Henry Moule designed a model he called the Earth Closet to ‘flush’ a small amount of dirt over waste that he then transferred into his gardens. He was drawn to create this model after deciding the cesspools of waste at his residence and around his neighborhood had become intolerable. Not only was it unsightly and reeked of sewage, it also exposed many of his parishioners and family to cholera.

Moule’s model looked like a standard wooden chair with a hole in the seat that a metal bucket was placed under. On the back side of the chair was a metal funnel that he would fill with dirt or ash and a small lever to pull after doing your business so dirt would drop from the funnel into the metal bucket. He discovered within a period of time the waste had integrated into the soil and created compost.

Although we’ve come a long way with understanding the composting process, this was a breakthrough for hygiene and sanitation in his living quarters because it reduced the risk of cholera and contact with sewage. By the 1880’s this model was patented and sold at Army and Navy stores.

While Moule’s model was a success, another breakthrough happened around the same time, one that many of us take for granted on a daily basis - the septic tank. The septic system was considered a more convenient option for people to invest in for their homes because you didn’t have to fill a funnel with dirt nor empty the contents of a bucket into a backyard trench or garden. The septic system was more widely adopted and has come to be the primary toileting solution in countries with improved sanitation facilities.

Almost 100 years later, in the late 1960s an organization called Clivus Multrum became the leader in producing composting toilets for commercial and residential use. They are still active today with projects across the US. For almost two centuries, people have been privy to the idea of an environmentally conscious privy, colloquially recognized as a compost or biologic toilet. While there used to be a difference based on the toilet’s composting capacity, the language between ‘biologic’ and ‘compost’ toilets has melded together and is essentially interchangeable today.

Our Design

So, with all of this history and model evolution, what makes Toilet Equity toilets different and why do we choose to use the models we have active in our Colorado River Corridor project?

At their core, Toilet Equity toilets aren’t all that different from Moule’s original concept. We currently have three active models in use in Western Colorado.

We have our standard 4’x4’ wooden toilet with a design option to allow for a larger, ADA-accessible version to be placed at hosting locations with more space to accommodate larger toilets. The wooden design allows us to transport the toilet and construct it on site so we are able to access more remote locations, ideally along the Colorado River. Although these designs take a team to transport and construct, it is important to us that our toilets are not permanent so we can best accommodate users’ needs in the area and abide by city and host requests.

Our third model is a converted port-a-potty toilet that we modify to fit our collection receptacle - rather than the standard septic style tank - so the contents can be removed and transported to our compost site.

The plastic toilets are the easiest to move because they are the lightest and we can just tip it onto a trailer, secure it and transport it as needed. The standard wooden toilets can also be tipped onto a trailer but it requires more people to do it safely. The ADA accessible toilets need to be deconstructed so we take off the roof and walls and ramp and pile the pieces on a trailer to move it.

On the interior of all our toilets is a bench with a collection bin beneath it and a urinal, along with a bucket of sawdust. The urinal drains into a 6 gallon jug, which helps keep the urinal drain pipe from freezing in the winter. This also helps eliminate excess liquid from our collection bins to prevent sloshing and allow for easier transportation. Sawdust is added to the toilet after each use but not to the urinal. The sawdust covers the deposits: this prevents odor, deters flies and pests, and kickstarts the composting process.

Many compost toilet designs you'll find with a quick internet search are suited to individual home use. Often, they do the composting right in the large bin the deposits go into. In many of these designs, the urine is directed away from the composting bin and is distributed outside the home as greywater.

Our toilets use a different system. We use smaller bins and change them out every other day, taking the deposits to a separate site where they're composted. Our toilets see far too many uses a day to do all the composting directly in the toilet bin - the receptacle would have to be enormous! We also very much want to keep the urine contained and add it to our compost piles. Not only would our hosts not appreciate a stream of urine coming out of our toilets, that urine provides essential nitrogen and hydration for our composting process, especially here in the desert of the Western United States.

Location

We let our hosts choose which toilet style will best suit their needs.

Some hosts prefer the port-a-potty because it’s more clear that it’s a toilet. Others like the wooden design because it is less obvious and looks more like a tool shed. All of our toilets hold the same capacity of collection bin and urinal jugs.

To compensate for the smaller size of our bins, we place extra toilets in locations that have higher traffic of users. For example, the Resource Center in Grand Junction has four of our toilets due to the hundreds of users that visit that location on a daily basis. This way, we can keep our maintenance and turnover schedule the same here as our other locations. If we had fewer toilets at that site, we would need to change the bins and jugs multiple times a day.

Looking Beyond

Ultimately, our mission at Toilet Equity is to create toilet access for those without, and it’s important to us that we do it while serving the health of our community and our environment.

Our motivation is a large reason why we opted for compost toilets as opposed to toilets that need a pump truck. Our toilets use significantly less water, are more cost effective to build and maintain, and we return the waste to the environment in a healthy, non-hazardous way leaving us with compost.

A big goal for Toilet Equity is to expand nationally and - hopefully, one day - globally, and it’s important that our toilets are able to adapt to the region of need. Currently, in Colorado, our wooden toilets are weatherproofed to prevent damage from snow and rain. When we expand to other regions it’s important our designs can be flexible to fit the environment and the communities needs. Our carbon additive can also be amended to the area. We use sawdust in Grand Junction, thanks to generous donations from a local company, Sawmill Unlimited. Other carbon additives could be tumbleweeds, hay or straw, leaves, pine needles and other creative options depending on what is accessible in each region.

In favor of increased accessibility, we want to launch a pilot program for individual compost toilets that allow individuals to participate in an exchange of sorts where they will receive a small bucket-style commode and a bucket of sawdust. We would have drop off locations once their buckets are full to exchange for a clean, empty bucket and a refill of sawdust. We’d then add their deposits to our compost piles. With this initiative, we hope to offer more flexibility to our unhoused population not to have to plan their days around being in locations near a toilet. This prototype would be very similar to that of a groover that many outdoor recreators use while camping or rafting. In fact, we’ve used this system as a groover on a raft trip which you can read more about here!

The Compost

The final component of any Toilet Equity toilet is the compost.

We have a small site with 10 piles and are in the process of expanding. Each pile uses aerobic systems, requiring oxygen to break down the contents.

Our piles started out with a few bins and an insulated layer of straw. As we add more deposits, we peel back the layer of straw with a pitchfork and dig down into the pile a bit to aerate and redistribute the contents.

We then dump the new collections into the middle of the pile so they are fully introduced to the most active area of the pile and the thermophilic bacteria takes to the new contents quicker. Depending on how much sawdust the new deposits contained, we will add a little bit more hay to the pile. Since hay is more expensive than straw we like to save it for the interior of the pile where it will do more good. If the contents have an odor then it’s a good indicator that not enough sawdust was used and the pile needs more carbon to compost properly.

We then level the pile and add in the urine jugs for hydration and added nitrogen. At this point we also add the water used from washing out the buckets. Finally we layer the pile with 8-12 inches of straw to keep it insulated.

Aerobic composting is the preferred method for our environmental health initiatives because it is faster, it kills harmful pathogens by creating a hot environment for thermophilic bacteria to thrive, and most importantly, it doesn’t produce methane gas.

Many compost toilets for residential use compost the contents inside the toilet itself using the anaerobic composting method. However, because of the minimal amount of users, there isn’t enough to create a methane buildup. Any biogas that is created in these toilets is often used for cooking and can produce up to two hours worth of gas daily.

There are so many options available for curating a composting toileting system that is suitable to your needs. At Toilet Equity we wanted to make sure our toilets would be practical for the environment and users they accommodate. It’s great to think that this has been an idea fostered for almost two centuries by like minded individuals who recognize the need for better toileting solutions while putting environmental health at the forefront.