Composting Toilet Options For Tiny Houses
One just never appreciates the vital nature of a well functioning toilet until theirs doesn’t work properly. We have gone through not just one, but two composting toilets for hOMe. Granted there are 3 of us living in it full time so I suppose we will put any toilet system to its full test. The first two turned out to not be viable options for us. The odor was awful, they were quite frankly dreadful to clean out, and we began to dread using them at all. The great thing that came out of those experiences is that we became incredibly informed consumers. The key factor in any composting toilet system is to find one in which the urine diverts from the solids. Those two frankly don’t belong together. The other factor to consider is the clean out process. Believe me, this part can be foul and I am in no way squeamish. Fortunately there are fantastic composting toilet options for tiny houses, one being the Separett.
We recently purchased the Separett composting toilet and we couldn’t be happier with it. It is SO easy to use, to clean and it has absolutely no odor to it whatsoever. This is hands down the best system out there as far as we’re concerned. The only downside we see is the cost (though we honestly believe it was worth every penny).
Richard Brunt, the man that we purchased our new Separett composting toilet from was kind enough to write an article for us regarding how the toilet works. If you are interested in the toilet and have questions, please don’t hesitate to contact him. He is easy to reach and eager to help. He’s a super knowledgeable guy that knows his poop! Without further delay, here is what Richard has to say:
Separett waterless toilets from Sweden are quite different from older style composting toilets. The key feature is the separation of urine and solids. This makes the whole process of dealing with human waste much simpler and easier.
Urine is basically sterile, and does not pose a health risk. It’s easy to dispose of – either in a small drain pit, or even as grey water (check your local codes). Some people collect the urine in a tank, dilute 10:1 with water and use it as fertilizer.
Solid human waste is about 80% water by volume. The fan in the Separett toilet vents the moisture outside, and the solid material begins to dry out. As it loses moisture, the waste shrinks drastically. This is why the capacity of the Separett toilet is so large. A family of 4 will probably empty about every 3-4 weeks. Note: the solid waste often does not completely dry out. It depends on the number of users. This is normal.
Also, very soon after the solid waste begins to dry out, most odor disappears. Any odor that remains is exhausted outside by the fan, which should ideally run 24/7. It is a very quiet fan, but it does make a whispering noise, so you want this toilet in a separate room from where you sleep. The fan draws about 3 watts with the Separett 9210 DC model (for batteries or a solar system) and about 17 watts for the Separett 9200 AC (which plugs in to a regular wall outlet).
Compare this to the older style composting toilets, which combined urine and solids together. Most of that liquid has to be evaporated before composting can occur, so many older style toilets use powerful electric heaters. If the heaters fail to evaporate enough liquid, composting never occurs – and you have a toilet full of raw sewage. The odor inside that toilet is horrifying. Depending on the model, there may be rotating drums, mechanical rakes or other complexities which can (and do) break down. If an older style ‘all-in-one’ toilet needs repair, and you need to take it apart, it is a very unpleasant job.
The Separett solves these problems, with its simple urine separating design. It does not require a heater or complex mechanical rotating mechanisms.
Inside the Separett is a container lined with a compostable plastic bag. When this bag gets full, you open the toilet, remove the compostable bag, and take it outside to a compost bin. It’s no more difficult than taking out the trash. The inside of the toilet remains clean, as human waste does not contact the inner workings of the toilet itself. The solid material should stay in this secondary container for about 6 months of above freezing temperatures, so the composting process can complete. It is then safe to put on non-edible plants.
Cleaning the bowl after each use is fairly easy. The Separett has a large trap door that opens automatically when you sit on the toilet. Most of the solids will drop into the lower chamber and not even contact touch the sides of the bowl. However, there is inevitably some cleaning required. Most people keep a spray bottle with water and a little vinegar beside the toilet. After each use they mist the sides of the bowl, and wipe it clean with a paper towel or toilet paper. The paper can then be dropped into the toilet.
One question I often get asked is “is the toilet legal?”. In most places, yes. Separett toilets are certified to the ETL standard for hygiene and health care. Some inspectors have asked if it is NSF certified. NSF is another testing agency, like ETL. However, NSF does not have a category for two stage toilets like the Separett, where composting has to complete in a secondary container. Neither certification – NSF or ETL – is a guarantee that a building inspector will approve any given composting toilet. Some counties love them, other counties remain skeptical. In my area, the inspector says “I like composting toilets, and I understand what you are trying to do. But the code books were written before composting toilets were around, and there is nothing here that talks about them. So don’t ask, and I won’t say no”. Use your own judgment and common sense.
Another frequent question is “what about flies?”. Fortunately, most people never have any trouble with flies. It is a bigger issue in the southern states, and tropical locations such as Hawaii – especially in open air homes without screens on the windows. The first line of defense is to keep the flies out of the house, and especially the toilet area. There are entire web pages devoted to keeping your home free of flies, so I won’t repeat their advice here. You can also add a product called diatomaceous earth to the solids bin. This helps a great deal, according to many people. If you do get a fly problem, remove the bin and the rotating plate that it sits on, and clean everything very thoroughly with a solution that will kill all fly eggs. (Do not get the fan wet, as that may destroy it. Do not flush the toilet out with a hose). Remember, the toilet is not producing flies. They are coming from somewhere. Eliminate the source and you eliminate the flies.
In the final analysis, Separett waterless toilets are one possible option for dealing with human waste in a tiny home. They are low cost, compared to a septic system, easy to install, easy to empty and maintain, and most importantly, odor free. You can learn more and purchase the Separett waterless toilet by visiting my Separett page. You can also read frequently asked questions about the Separett here: Separett FAQ
In closing, here is a short Tiny Minute we made of how it works: