Privies (toilets) are common at many shelters on the Appalachian Trail.
There are several different types:
- Pit toilets - The traditional repository. (A pit toilet with no privy shelter is called
a chum toilet.) Because anaerobic waste breakdown in a pit is slow, pathogens
may remain viable for years. The waste in poorly placed privies can leach contaminants
into the surrounding area years after use has ceased. However, pits
work well when properly sited and not overused. The level of use must match
local soil characteristics. If you are considering a pit toilet, contact your regional
ATC office for information on siting and installation.
- Modified pit toilets-These attempt to avoid anaerobic decomposition in favor of
aerobic decomposition. Modifications include:
- Composting toilets-These are a major improvement over the above methods of
disposing of fecal waste. Site limitations such as shallow soils or high water tables,
coupled with heavy use, have led to the development of batch-bin composting
and moldering privies, as well as more expensive manufactured aerobic composting
In a composting toilet, raw wastes are held apart from the surrounding site until
sufficiently decomposed to be spread over the forest floor. However, waste policy
on federal land in the west frequently dictates that even treated waste be transported
out of the backcountry.
- Moldering Privy -
Moldering means slow, or cool, composting. This is in contrast
to quick, or hot, composting, which is the process on which a batch-bin
composting system relies. Temperatures range from 40-99° F.
- The crib sits above a shallow depression, only a few inches deep, which confines
urine so it will percolate into the biologically active layer of the soil.
- The pile of human waste mixed with bulking agent in the crib is above ground,
so it cannot become waterlogged.
- Users are asked to add a small amount of bulking agent with each
use. The bulking agent (duff or leaves) need not be kept dry since, unlike batch-bin composting, it
need not absorb liquid.
Duff or Detritus mainly consists of shed vegetative parts, such as leaves, branches, bark, and stems, existing in various stages of decomposition above the soil surface in a forest.
The moldering privy was developed in a continuing research
project by the Green Mountain Club (GMC) in conjunction with the Appalachian
Trail Conference (ATC), the National Park Service Appalachian Trail Park Office
(ATPO), and the Vermont Department of Forests, Parks, and Recreation (VT FPR).
Dehydration and incineration toilets-These are commercially available. Results
have been mixed. Provision of fuel (usually propane) can be expensive and disruptive,
and offensive odors have been reported in some cases.
Guidelines for use:
Urine in anaerobic systems
such as a pit-toilets substantially increases offensive odors. Depending on the
design, urine can be either an asset or a liability in aerobic composting systems,
but odors are much less of a problem in either case.
Newer privies have a ventilation system which minimizes odor, but the cover for the seat or hole must be kept closed when not in use.
Read more: http://www.motherearthnews.com/modern-homesteading/outhouse-ventilation-zm0z02zsie.aspx#ixzz1TEKjgfTv
Appalachian Trail Conference, Backcountry Sanitation Manual (pdf)
last updated 23 June 2011