Have a seat... composting toilet

Feb. 22, 2009

Have a seat... composting toilet
Harley L. Sachs 2/23/09


So you found that perfect place to build your vacation cabin. The views are lovely and you made plans to build. But there’s a catch: The building site on the shore of Lake Superior is solid rock. You’re nowhere near any water mains or municipal sewer system. There’s no place to dig a hole for a septic tank, and even if there were, there’s no soil suitable for a drain field. Your family doesn’t like the idea of a pit toilet privy, either. Are you sunk? Not necessarily.
There are many parts of the country where a conventional water-flushing toilet is impractical. An alternative is a composting toilet. It can not only dispose of “humanure” and urine, but can digest table scraps and function as a garbage disposal as well. Some people actually hasten the digesting process with worms.
I first learned about composting toilets in Sweden where “stugas” (cabins) in the mountains of the north were so equipped. The tidy Swedes didn’t want their garbage strewn along the ski or hiking trails. Everything in “the nature” had to be pristine.
Composting toilets come in many designs from do-it-yourselfers to any of a dozen different manufacturers’ commercial models. The end result is essentially the same whether urine is separated out, as in some systems, fan-dried, or processed through a sequence of three compartments. If there is vegetable matter, such as dry leaves or sawdust available, that can be added to reduce odors.

YEAR-LONG PROCESS
It takes about a year for the waste material to cure sufficiently to be handled safely and used for mulching around bushes, trees or vegetable gardens. The waste product is not recommended for use on leafy vegetables. You don’t want a salad contaminated by human fecal matter. This is, however, not what is called “night soil” and spread on the strawberry patch in some countries. By the time the compost from a properly designed “dry” toilet is cured, the pathogens are gone.
Composting toilets do take up more space but, unlike the old-fashioned conventional pit toilet or latrine which fills up, might not need emptying for decades, providing the tank is large enough to hold three times the annual deposits. As humanure dries, it is reduced to only one or two percent of the original volume. What remains is mineralized soil.
If you’re keen on using the humanure for fertilizer, it’s best to separate out the urine. Urine contains 90% of the nitrogen and 50% of the phosphorus and is nearly pathogen free. Urine is so nearly sterile that a primitive way to sterilize, say, an injured foot, is to pee on the wound.
If you’re thinking that a composting toilet is going to be as stinky as the old two-holer on the farm, rest easy. If properly vented and drained of urine, there’s little or no smell. To hasten the drying, lime is sometimes added.
Before you install a composting toilet at that remote camp or anywhere else, make sure you contact the local health department. Not everyone is familiar with the water-saving benefits and safety of composting toilets. It’s best to be well-informed first. Here (thanks to the Wickipedia) are the names of some manufacturers:

• Advanced Composting Systems LLC
• Biolet
• Biolytix
• Biosun
• Clivus Multrum
• EcoTech Carousel
• Ecoflo Water Management
• Enviro Loo
• Envirolet (Canada)
• MullToa Waterless Composting Toilets
• Nature-loo
• Nature’s Head
• Sun-Mar
• Sunfrost
• Separett

SMELL FACTOR
Manufacturers claim that there’s little or no smell involved in a compost toilet system because of positive suction of air through the toilet at all times, even to the point of having a vacuum flush. “In fact, there should be less smell than a conventional toilet,” claims the Envirolet company of Canada.
Canada has been a big producer and user of composting toilets, owing to the many cottages in northern Ontario. Australians are also increasingly using the toilets, which can be 25-75 percent less to install than a standard septic system.
The toilets also save on water, a factor which could be of increasing importance in drought-stricken regions.
Of course, you don’t have to buy a commercial composting toilet. There are many designs for the do-it-yourselfer. It’s a lot more work than just digging a hole and parking a privy over it. In fact, if you visit the health department for the specifications they demand for a simple pit toilet, you may find it’s going to be cheaper to build your own composting system.