Composting Toilets Are Coming Home

Many people think the idea of putting composting toilets in homes is crazy. One commenter noted earlier when I suggested it: "No one will want this inside their house. I know this, because I still have a few teeth in my head and a few friends in town." But more and more, people are going off-pipe; my friend Laurence Grant has done it for almost 20 years; now energy consultant Allison Bailes describes how he did it in Green Building Advisor and how his bathroom actually smells better than yours.

We installed the kind of composting toilet with a large tank in the basement. The tank had a small fan that constantly exhausted air from the tank through the vent on the roof. So, whenever anyone went to the bathroom and ... uh ... did their business, the bathroom smelled better than before they went in there. The reason is that as soon as they opened the lid on the toilet, air from the bathroom was being pulled down through the toilet, into the basement tank, and then sent out through through the roof.

Almost all composting toilets operate this way, with a fan creating a negative pressure so that smells are exhausted. Some run the exhaust through a heat recovery ventilator to recover any heat (and there is quite a bit) in the air; the composting action generates quite a bit and the air sucked in is already warm.

Both Allison and Laurence, and I am sure many others, can attest that properly managed, a composting toilet doesn't smell and isn't scary.

Allison's Practical Advice

Here is where I feel I must argue with Allison's advice, particularly his first bit: Don't get a small one. He has a big Phoenix system with a box in the basement. I absolutely agree that if you have the space, this is the way to go. The maintenance is easier and the physical and psychological separation from the pile of poop is greater. With some systems like Clivus Multrum, you don't ever have to deal with cleaning it out; they will sell you a service contract and to it for you.

But to say Don't get a small one cuts the great majority of the possible user base, eliminating the use of composting toilets from people without basements or room to put the tank. It costs a lot more money. And while Allison has friends who hated it, there are thousands who do not, including me (a part time user) and others like Laurence.

Consider a foam-flush or micro-flush toilet.

Some people are squeamish about doing what comes natural into a tank where they can see that other people have also been doing what comes natural. Crazy, I know, but it’s true. These types of toilets also give you the flexibility to install the toilet in locations other than directly above the tank.

Both the foam flush and micro-flush alternatives serve one function: make it feel like a more conventional toilet experience. Both cost a lot more money and don't work as well; I had a microflush system and it delivered lousy, soggy compost. It located the tank a few feet horizontally from the toilet and spent my summers with a snake undoing the clogs. I dumped it for the so-called "small" one-piece toilet. It works far better.

You are sitting on poop while you use a conventional toilet. With a composter you are sitting over a larger pile of poop. It's not so terrible, get over it.

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