Compact Composting Toilets – Do They Really Compost?

The great debate!

There seems to be a lot of controversy over whether certain “composting toilets” are in fact composting toilets. Joe Jenkins addresses this question in his book “The Humanure Handbook” which is available for free (here). I have the highest respect for him for giving away (for the benefit of mankind), all his hard research on composting human waste. His book isn’t expensive and I encourage everyone to buy it outright (here) and give him the reward he is due. But to the point, he points out in it that the definition of what constitutes a “composting” toilet is basically in the eye of the beholder.

Joe Jenkins’ Humanure Handbook
a must read

Jenkins’ system using the “Lovable Loo” is basically a “bucket and chuck it” system where the urine and feces are mixed and covered with any kind of carbon based medium that will bury the waste sufficiently to keep it from smelling. It is the composted outside the toilet in a large compost bin for use in gardening. The process can take a year to be safe. Urine diverting composting toilets on the other hand can accelerate this process significantly and with more certainty by separating your pee and poop at the point of use. The “bucket and chuck it” non-urine diverting method relies on thermophilic composting to convert the waste to usable material and requires a large amount of compostable material to be available for processing the waste.

Composting is a process and every toilet that initiates the composting process could correctly be called a composting toilet. In the case of the C-Head, you can hold the back of your hand over the opening in the collection bucket and feel the slight heat being radiated from the waste as it accumulates. Mold can also often be seen growing on the surface of the waste, and while some people find this a little disconcerting, it is the very definition and proof of composting taking place. The disagreement comes with whether or not the waste is totally composted inside the toilet. By that we normally mean that it is no longer recognizable as the waste it was and it is free of harmful bacteria. Toilets that accomplish this are usually very large and expensive which limits their practical application. Smaller composting toilets could be called something else that differentiates them from the larger ones but I’m not sure that it is necessary. Most people are going to be reluctant to directly expose themselves to the contents of the toilet no matter how well composted the waste is said to be, be it fully composted or not. 

Since most of composting toilets have some kind of ventilation system that removes excess moisture and in doing so helps dehydrate the waste, they could just as easily be called “dehydrating” or “desiccating” toilets and some people insist that this is what they are. The whole thing is splitting hairs. It is like using the term “Kleenex” when referring to any soft tissue. Compact, urine diverting toilets are recognized as “composting” toilets and that should suffice. Until the government comes up with a legal definition for what is and isn’t a “composting toilet”, let’s use the term most recognized by the public. 

Composting tower

I would argue that if you want to be sure that human waste is safely composted, there are several processes the waste should be exposed to and to do that effectively, the waste should be composted outside the toilet where it can be more easily managed and the quality of composting verified. For instance, we assume that thermophilic composting (heat) and the passing of time is what destroys the harmful bacteria. But there are other available avenues that will do the job more quickly and better. For instance, altering the pH of the waste, exposing it to UV, and to total dehydration (read more) will go a long way towards making it safe for use and can be accomplished in a very short time frame. Most bacteria that is harmful to humans lives in a narrow range of temperature, pH and moisture, similar to that found inside the human body. Some nematode parasites (worms) can survive a wide range of elements and can be difficult to destroy, however these parasites are not common in the United States and the risk of spreading them using a composting toilet and basic personal hygiene is extremely low.

Using a small burn pit to incinerate
dried solid waste.

Of course the very best way to protect against spreading any kind of disease from human feces is to burn the feces and using a composting toilet facilitates this action when burning it is the best course. Assume for a moment that a family member becomes sick or that a gastroenteritis infects the whole family. Having just the solid waste mix with a carbon based medium like sawdust makes it easy to dehydrate for burning or to burn outright if you have a large enough fire. Diarrhea can be converted to a drier material by simply adding an absorbent like pine pellets or corn cob pellets to the mix. Burning feces mixed with urine (called sewage) requires a lot of energy and handling a slurry of contagious material is much more dangerous and likely to cause a spread of the disease than handling a dryer material.

We will explore all these avenues in detail in future articles on the BoonJon garden and describe ways to manage your waste in a true permaculture environment as well as on board a boat or RV. We will examine how to make a simple and inexpensive solid waste dehydrator and other systems for processing your waste of every kind. Please feel free to ask questions or make comments below that contribute to the discussion and follow us for coming articles. 

Please feel free to make constructive comments or ask questions below.

Copyright 2019 – C-Head LLC – All rights reserved on all content.

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