The sprawling tentacles that constitute the water infrastructure in the United States spill about 860 million gallons (3.3 billion liters) of untreated water -- along with all the raw waste that involves -- each year. If you add in all the clean water lost, that amount soars to about 6 billion gallons (22.7 billion liters)spilled each day [source: Gleick and Ellis-Lamkins]. But while the loss of clean water is a serious waste of a precious natural resource, it's the untreated water that's most troubling. That's because human fecal matter and urine, when not disposed of safely, can cause numerous environmental and health problems in the world's waterways.
Some people, however, are proactive about preventing their personal waste from becoming part of this spewing stream of potential pollution, and treat their bathroom business as a natural process that can produce a beneficial result. That result? Humanure. The idea is to compost human urine and manure and turn it into a useful, reusable byproduct [source: Jenkins]. Whether that byproduct -- a natural fertilizer -- is used to make food-growing soil more fertile is a matter of personal preference. Some say go for it, while other practitioners caution against it, reserving the compost for ornamental planting purposes. But everyone in the pro-poop-composting-camp agrees that it's wasteful if not downright irresponsible to not take these matters seriously.
In fact, those who don't appreciate the process are sometimes referred to as fecophobes by composting aficionados. Fear of, or at least distaste for, feces is a cultural norm in many parts of the world -- especially the Western Hemisphere -- no matter how often children are read "Everybody Poops" as a bedtime story. From the father of biodynamic agriculture, Rudolf Steiner, to the public outreach department of U.S. Department of Agriculture, the message has historically been consistent and adamant: Human waste is a dangerous and potentially deadly substance.
But people who advocate composting human waste say otherwise. While in its raw and original state, yes, it can pose a serious public health risk. But after being composted, humanure devotees claim it's not only safe to use as fertilizer, it's the only way to go to keep the overall environment in a healthy and flourishing state. On the next couple of pages, we'll take a look at how people construct and maintain composting toilets in outhouses.
Building the Outhouse
A regular outhouse, also known as a pit latrine, is not what you want if you're looking for an environmentally harmless and aromatically acceptable solution for human waste management. These setups involve simply digging a hole in the ground, then covering it over with dirt when it starts to get full. The droppings are free to harbor dangerous microbes, attract pestilent insects, and gradually contaminate groundwater.
A composting outhouse is very similar structure but an entirely different setup. Simply put, the goal is to make human remains recoverable and recyclable. You can build a composting outhouse that requires less frequent large-scale upkeep, or one that needs regular small-scale maintenance. In order to properly compost in the former, you'll probably want to build an elevated outhouse on stilts with a few steps running up to it. This elevated plan provides easy access to the container in the composting portion of the facility. If you want to go the frequent-and-modest maintenance route, your outhouse probably doesn't need to be elevated -- it can just be a box-and-bucket setup.
Once you've determined your size and upkeep preferences, the early stages of construction are similar to building any outhouse, sans digging a soon-to-be-smelly pit. The dimensions and building materials used for a conventional outhouse will work here as well. But with composting outhouses, as opposed to pit latrines, waste instead ends up in (typically mobile) catchment containers located below the toilet seat. We'll talk more about the details of composting and what goes into those containers later in the article.
The last major consideration in your composting outhouse design is to plan a reliable ventilation system. A pipe installed like a chimney running from the collection area to the roof is a good way to accomplish this, but skilled DIYers can probably cook up other means to solve this part of the puzzle. The point is to make sure air can flow through the holding pen while it's waiting to be emptied.
On the next page, we'll take a closer look at the toilet itself.
Building the Composting Toilet
Composting toilets have several positive attributes. They save water, they use no energy, they recycle human fecal waste in a safe, sustainable and sanitary fashion while producing a useful byproduct, and they do all that without giving off an unpleasant odor. So once you have your outhouse constructed, it's time to talk toilets.
There are lots of different setups you can build. Your composting toilet can be as simple as a plastic bucket or a clay urn under a seat. Another standard example is a larger two-chamber model. One chamber is used until it's full, then rested while the second chamber is used. How often a swap happens will depend on how big your buckets are and how many people are using your outhouse.
Some composting toilet systems mix urine and feces, others separate them. Either route has pros and cons. The latter requires a little more effort during potty breaks but starts off as a drier mix; the former requires less thought when nature calls, but needs a little more help attaining ideal moisture levels. If you do decide to let everything mix, it can help to prep your bucket with a layer of moisture-absorbing plant matter like hay or straw before use. The whole idea is to make sure the mix is relatively dry -- and, by extension, relatively odorless -- as possible.
When it comes to the seating setup, you can do everything from building a box with a hole cut in the lid and a plywood top, to attaching a toilet seat and cover. It's really just a matter of how much you care about the creature comforts of anyone who will be using it. Once you've built a composting toilet for your outhouse, you're ready to go. Literally. Find out how you should take care of your new outhouse setup on the next page.
Maintaining the Setup
It's not possible to flush-it-and-forget-about-it if you're using a composting toilet, but they can be fairly low-maintenance, depending on the setup. Someone needs to be in charge of the process on an ongoing basis, to ensure everything proceeds according to plan. One of the fundamental aspects of maintaining an outhouse with a composting toilet -- and the resulting compost piles -- is to ensure that conditions are right for successful composting. There are four main variables that need to be monitored and correlated: temperature, moisture, oxygenation and time.
In terms of temperature, the safest way to compost is by creating thermophilic conditions. In other words, the humanure must warm past the temperature where pathogens thrive. This is especially true if your compost will be used as fertilizer for food crops. If you go for a low-temperature setup, you'll want to give the compost more time to mature and eventually deposit it on ornamental or unused land, just to be safe.
You'll also need to settle on a material to serve as a carbon-based bulk and make sure it stays well stocked. The point of adding carbon (especially if you do go with a composting toilet that combines urine and feces) is to help nix the nose-offending odor, promote proper composting by increasing the oxygen flow, reduce excess moisture and balance out the levels of nitrogen present in your potty. Then, every time someone uses the composting commode, he or she simply tosses a scoopful of the material down on top to cover it. The substrate can be all or a mixture of particles such as sawdust, peat moss, ashes, straw, hay, leaves or other yard trimmings. And that's really all the involvement needed from anyone who isn't in charge of the management of the compost pile.
For the person who is in the role of compost caretaker, he or she has a few more responsibilities. The compost pile site must be selected (locations well away from groundwater sources are obviously recommended) and enclosures built. A three-bin system works well. First one is filled, then the second is filled while the first is allowed to rest. One to two years is a good period of time for the process to unfold. The central third compartment holds influxes of carbon material that occur throughout the year -- say ashes from the fireplace during the winter months and grass clippings from the lawn during the summer. On a regular basis, the person running the show will occasionally need to empty the buckets, flatten out the layers of leavings and ensure everything is being properly covered by the carbon material.
A layer of substrate should be laid down at the start, and then added each time an addition is made. This will trap oxygen within the pile, and help increase and regulate the temperature. The lower the temperature the longer it takes to kill any lingering pathogens. One expert on the subject, Joseph Jenkins, recommends keeping the temperature at or above 109.4 degrees Fahrenheit (43 degrees Celsius) for at least one month to ensure complete pathogen destruction [source: Jenkins]. Hotter temperatures can achieve this at a much faster rate. The compost pile won't have completely converted to humus at this point, but any pathogens should be dead. Once the appropriate heating has taken place, it's smart to just let the compost pile rest undisturbed for a year; two to be on the safe side. Additional piles can continue the process in the meantime.
Last but not least, let's cover moisture. The starter material -- that which is collected in the composting bucket toilet -- is obviously pretty moist. In your compost pile, the little microbes and other small organisms that will break down the humanure into humus need you to strike a balance between moistness and dryness. Basically, it's these micro and macroorganisms the whole process caters to. You want to keep them warm, hydrated, well fed and with enough oxygen to stay happy and hungry.
Ready to defy the fecophobes and get composting? Get more helpful information on the next page.
- How Toilets Work
- What if everybody in the United States flushed the toilet at the same time?
- How green is a self-contained composting toilet?
- How Indoor Automatic Composting Systems Work
- What's the most expensive toilet in the world?
- How Composting Works
- How Vermicomposting Works
- How Sewer and Septic Systems Work
- How Living Off the Grid Works
- How the ZeroHouse Works
- How Green Building Works
- Why can't we manufacture water?
- "Composting." Decision Maker's Guide to Solid Waste Management, Volume II. EPA. 1995. (Oct. 27, 2011) http://www.epa.gov/osw/conserve/rrr/composting/pubs/chapter7.pdf
- Envirolet. (Oct. 27, 2011) http://compostingtoilet.org/
- Gleick, Peter and Ellis-Lamkins, Phaedra. "Jobs and Water for America." Forbes. Oct. 5, 2011. (Oct. 27, 2011) http://www.forbes.com/sites/petergleick/2011/10/05/jobs-and-water-for-america/
- Griswold, Kent. "How to Make a Composting Toilet." Tiny House Blog. Aug. 19, 2011. (Oct. 27, 2011) http://tinyhouseblog.com/tiny-furnishings/how-to-make-a-composting-toilet/
- Jenkins, Joseph. "Humanure Compost Toilet System Instruction Manual." Humanure Headquarters. (Oct. 27, 2011) http://humanurehandbook.com/manual.html
- Jenkins, Joseph. "The Humanure Handbook." 1999. (Oct. 27, 2011) http://www.weblife.org/humanure/index.html
- "Leading Compost Toilet Information and Advice." CompostJunkie.com. (Oct. 27, 2011) http://www.compostjunkie.com/compost-toilet.htmlMoser, Nick. "Construction of a Composting Toilet." The Shire Institute. Feb. 1, 2008. (Oct. 27, 2011) http://www.the-shire.org/index.php/Eco-Blogs/construction-of-a-composting-toilet.html
- "Water System Audits and Water Loss Control." Delaware River Basin Commission. April 13, 2011. (Oct. 27, 2011) http://www.state.nj.us/drbc/water-audits/overview-najjar.pdf