Sun Mar Composting Toilets |     home

Sink, shower, laundry water waste

Frequently Asked Questions

How Does the Toilet Work

The self contained units (Excel, Compact) are truly self contained. With the electric models there is a small fan that runs to circulate the air through the toilet to help evaporate the liquids. The waste goes into the bio drum which allows the solids to compost in an aerobic (oxygenated) environment. Liquids that go into the bio drum go through a screen at the back of the drum into an evaporation pan located at the bottom of the toilet. A heater at the bottom of the pan helps to evaporate liquids as well.

In the bio drum is a peat moss/hemp fiber compost mix that you add at start up. When you defecate into the toilet you use a cup of the peat moss mix after using toilet paper. This is not required for urination.

When the bio drum starts to fill near the bottom of the trap door (1/2 to 1 inch) you turn the bio drum crank in the opposite direction (after releasing the lock) and empty some of the contents into the finishing drawer located at the bottom of the toilet. In several weeks you remove the finishing drawer content and bury it around your trees or flowers (vegetable gardens see below). It does not have an odor.

How Often Do You Mix the Compost?

We turn the handle that rotates the biodrum about once a week for about 6-7 turns. With continuous usage you may need to turn every other day or so. They key is to turn the drum so that you can mix the compost and maintain an aerobic (oxygenated) versus anaerobic environment. An anaerobic compost will produce odors.

What Can Go Into the Toilet?

Only what comes out of your body and toilet paper. Other paper, food, feminine supplies need to go in the trash can. Special toilet paper is not required.

Can You See What is in the Toilet?

The rim and bio drum are black so the contents you may not want to see are in a dark area. Only if you shine a flash light will you really see what's in the toilet. If you do not want to see the inside get a central processing system with a water flush toilet. For proper maintenance you will need to shine your flash light to check that the compost is moist if the toilet does not get used daily. Water may need to be added. Dry compost can bring small flies in some instances. If small flies are present in the drum or evaporating chamber we spray some earth friendly bug spray into the area.

Does The Bacteria Always Work?

In the winter months if you toilet is in a non heated area the beneficial bacteria will hibernate and the composting process will stop. This is not bad except that you will have to wait longer for the compost to mature. Rooms with temperatures below 60 degrees F should be heated if you want to use the toilet. This is normally not a problem in a cabin or home.

Can I Use the Finished Compost in My Vegetable Garden?

It is recommended that the finished compost be placed in flower gardens and around trees due to the possibility of parasites and roundworms that may be in human feces.
One could argue that it you currently do not have parasites/worms then your feces would not. To be totally safe Thermophilic (high heat) composting kills such parasites and worms making the compost safe for vegetable gardens.

If you wish to use the compost in the garden build a compost bin and follow the procedures listed in the Humanure Handbook written by Joe Jenkins. Use a compost thermometer (sold on amazon) to insure the compost pile reaches temperatures to kill parasites, etc.

Are They Difficult To Install?

Each toilet comes with what you need. The vent piping, flashing, connections are included as well as a bag of the peat moss mix and bacteria. The self contained units sit on the floor and plug into a regular outlet. The vent kit goes through the wall or ceiling which requires some carpentry (cutting a hole).

Is There Any Maintenance?

We use the Compact model at our bed and breakfast and have found that maintenance is minimal. Every six to eight months we clean out the evaporating chamber (picture above) located on the bottom of the unit. This pan is where the urine goes to evaporate. After 6-8 months we notice that the pan develops a crusty buildup and also shows some peat moss that has fallen through the screen on the back of the bio drum. The peat moss can be raked out with the small rake that comes with the toilet. We installed a flexible section in the vent pipe to easily disconnect the vent from the toilet. We move the toilet to the outside, add some soapy water to the chamber and let it sit for a few hours to loosen the crusty residue. Then we hose it out and drain the soapy water through the plugs on the back of the unit. It's easy to do and is part of our maintenance program. If your drain plugs are always connected you probably could do this procedure (adding the soapy water) without removing the toilet.

There is nothing else we do in terms of maintenance except keeping an eye on the moisture level of the compost that was noted earlier.

Can Composting Toilets be Used in Commercial Applications?

Yes, they can be in supervised applications where you have an attendant or staff on site. We personally do not recommend a composting toilet that requires turning (like many Sun Mars and other brands) in city park and campground applications. In unattended areas we have seen composting toilets that have been abused by adding drink cans, bottles, etc to the composting chambers. Cranks to turn the drum are also a tempatation for children and many adults which may cause the toilet to not work properly if turned too often.

Are Composting Toilets Legal in My State?

Visit the county health department in your area to make totally sure. Many areas allow privies or outhouses and a composting toilet is a much more sanitary alternative.

Independent Sun-Mar Dealer , c/o Cedar House Inn
6463 Highway 19 North, Dahlonega, GA 30533
(706) 867-9446