Composting Toilet – How it works
What about the poop? Everyone wants to know how we could possibly use a toilet that doesn’t flush and doesn’t use water. And how can it NOT smell? Most of this text is from the Nature’s Head, Incinolet and Sun-Mar websites since they are thorough and easy to follow.
We are using the Nature’s Head composting toilet. Nature’s Head, Incinolet and Sun-Mar each make a composting toilet that will work in an RV application. For us to make the right decision we needed to compare things like size, weight and price of each model. In the RV, you have to carry everything you need with you, including your water. We saw using a composting toilet as an opportunity to use less water, increasing our ability to stay off the grid and boondock as well as an excellent way to reduce our need for a precious and dwindling resource, water. At first we wanted to use the Sun-Mar toilet because it evaporated urine (and we were uneasy about emptying the urine container on the Nature’s Head unit). But after considering several factors, (having to completely change our bathroom floor plan was the big one) we decided that the Nature’s Head unit was the best choice for our application.
In the Nature’s Head unit, the liquids are not mixed with the solid wastes and you get an exceptional amount of uses before you need to empty the unit. For example; a couple using their boat or cabin on the weekends may go an entire summer without having to empty the solid’s tank. We will be using it every day so we empty the solids about every 1.5 – 2 months. The front liquid tank is approximately 2.2 gallons and will need to be emptied more frequently – about twice per week. Check local regs. to know where and how you can dispose of urine. Many gardener’s water down urine and add it to their gardens (click here for Mother Earth News article). Collecting and disposing of urine was the trade off with using the Nature’s Head versus Sun-Mar and Incinolet. The others evaporate the urine using electricity. However, both units are much bigger in size and would not fit into our RV bathroom unless we reconfigured the floor layout. The existing RV toilet dimensions were H-12.5 inches, W-14 inches and D-18 inches. The Nature’s Head unit is H-20, W-13 and D-17. The Sun-Mar mobile unit is H-30, W-19.5 and D-23. The Incinolet RV model is H-20, W-15, D-24. Weight was also an issue – Nature’s Head weighs 28 pounds, Sun-Mar 40 pounds and the Incinolet 100 pounds. The price was the last factor – NH was around $850, Sun-Mar mobile unit around $1550 and the Incinolet RV unit around $1700. In the end, you have to look at all the factors and decide what is right for you.
In the Nature’s Head composting toilet, the toilet separates the liquids from the solids (to put it politely) – it doesn’t smell bad. It’s when you mix the urine and the solids that you get the really bad odors associated with sewage. When working properly the toilet will have a slight earthy smell when you open it. The vent to the roof allows moisture to escape. The resulting compost is a valuable resource which is ideally suited for uptake by plants, and goes from a composition of roughly 70% water down to 10%. This is truly a breakthrough and shouldn’t be overlooked as a viable waterless toilet alternative.
The Nature’s Head unit also contains a lock that ensures that the composting drum is held upright under road conditions. The toilet is very economical to operate; there are NO chemicals to buy. Throw in a little bit of peat moss or be even more sustainable and use coconut coir. Throw in a little coir, crank the handle, spray down with a vinegar solution every once in a while and you’re done.
Sun Mar Mobile