Commercial composting toilets have been popular in Scandinavia for some time; at least twenty-one different composting toilets were on the market in Norway alone in 1975.9 One of the most popular types of commercially available composting toilets in the United States today is the multrum toilet, invented by a Swedish engineer and first put into production in 1964. Fecal material and urine are deposited together into a single chamber with a double bottom. The decomposition takes place over a period of years, and the finished compost gradually falls down to the very bottom of the toilet
chamber where it can be removed. Again, the decomposition temperatures remain cool, not usually climbing above 320C (900F). Therefore, it is recommended that the finished compost be buried under one foot of soil or used in an ornamental garden.10
Because no water is used or required during the operation of this toilet, human excrement is kept out of water supplies. According to one report, a single person using a Clivus (pronounced Clee-vus) Multrum will produce 40 kg (88 lbs) of compost per year while refraining from polluting 25,000 liters (6,604 gallons) of water annually.11 The finished compost can be used as a soil additive where the compost will not come in contact with food crops.
A 1977 report, issued by Clivus Multrum USA, analyzed the nutrient content in finished compost from seven Clivus Multrum toilets which had been in use for 4 to 14 years. The compost averaged 58% organic matter, with 2.4% nitrogen, 3.6% phosphorous, and 3.9% potassium, reportedly higher than composted sewage sludge, municipal compost or ordinary garden compost. Suitable concentrations of trace nutrients were also found. Toxic metals were found to exist in concentrations far below recommended safe levels.12
If a multrum toilet is managed properly, it should be odor and worry-free. As always, a good understanding of the basic concepts of composting helps anyone who wishes to use a composting toilet. Nevertheless, the multrum toilets, when used properly, should provide a suitable alternative to flush toilets for people who want to stop defecating in their drinking water. You can probably grow a heck of a rose garden with the compost, too.
Inexpensive versions of multrum toilets were introduced into
Guatemalan Composting Toilet
Source: Schiere, Jacobo (1989). LASF Una Letrina Para la Familia. Cornite Central Menonita, Technologia Apropriada, Santa Maria Cauque, Sacatepequez, Apartado Postal 1779, Guatemala Cuidad, Guatemala.
the Philippines, Argentina, Botswana and Tanzania, but were not successful. According to one source, "Compost units I inspected in Africa were the most unpleasant and foul-smelling household latrines I have experienced. The trouble was that the mixture of excreta and vegetable matter was too wet, and insufficient vegetable matter was added, especially during the dry season." 13 Poor management and a lack of understanding of how composting works may create problems with any compost toilet. Too much liquid will create anaerobic conditions with consequent odors. The aerobic nature of the organic mass can be improved by the regular addition of carbonaceous bulking materials. Compost toilets are not pit latrines. You cannot just defecate in a hole and walk away. If you do, your nose will soon let you know that you're doing something wrong.
Besides the Scandinavian multrum toilets, a variety of other composting toilets are available on the market today. Some cost upwards of $10,000 or more and can be equipped with insulated tanks, conveyers, motor-driven agitators, pumps, sprayers, and exhaust fans.15
According to a composting toilet manufacturer, waterless composting toilets can reduce household water consumption by 40,000 gallons (151,423 liters) per year.16 This is significant when one considers that only 3% of the Earth's water is not salt water, and two-thirds of the freshwater is locked up in ice. That means that less than one percent of the Earth's water is available as drinking water. Why shit in it?
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