A type of sanitary privy in which the excrements are received directly
into a water-tight receptacle containing chemical disinfectant is meeting
with considerable favor for camps, parks, rural cottages, schools, hotels,
and railway stations. These chemical closets,[4] as they are called, are
made in different forms and are known by various trade names. In the
simplest form a sheet-metal receptacle is concealed in a small metal or
wooden cabinet, and the closet is operated usually in much the same manner
as the ordinary pail privy. These closets are very simple and compact,
of good appearance, and easy to install or move from place to place.
In another type, known as the chemical tank closet, the receptacle is a
steel tank fixed in position underground or in a basement. The tank has a
capacity of about 125 gallons per seat, is provided with a hand-operated
agitator to secure thorough mixing of the chemical and the excretions, and
the contents are bailed, pumped, or drained out from time to time.
[4] Among publications on chemical closets are the following: "Chemical
Closets," Reprint No. 404 from the Public Health Reports, U. S. Public
Health Service, June 29, 1917, pp. 1017-1020; "The Chemical Closet,"
Engineering Bulletin No. 5, Mich. State Board of Health, October, 1916;
Health Bulletin; Va. Department of Health, March, 1917, pp. 214-219.
[Illustration: Fig. 13.--Two-seat vault privy.]
Chemical closets, like every form of privy, should be well installed,
cleanly operated, and frequently emptied, and the wastes should receive
safe burial. With exception of frequency of emptying, the same can be said
of chemical tank closets. With both forms of closet thorough ventilation
or draft is essential, and this is obtained usually by connecting
the closet vent pipe to a chimney flue or extending it well above the
ridge-pole of the building. The contents of the container should always be
submerged and very low temperatures guarded against.
[Illustration: Fig. 14.--Two-seat vault privy. Note the shallow,
water-tight, easily cleaned concrete vault.]
As to the germicidal results obtained in chemical closets, few data are
available. A disinfecting compound may not sterilize more than a thin
surface layer of the solid matter deposited. Experiments by Dr. Alvah H.
Doty with various agents recommended and widely used for the bedside
sterilization of feces showed "that at the end of 20 hours of exposure
to the disinfectant but one-eighth of an inch of the fecal mass was
disinfected."[5] Plainly, then, to destroy all bacterial and parasitic
life in chemical closets three things are necessary: (1) A very powerful
agent; (2) permeation of the fecal mass by the agent; (3) retention of
its strength and potency until permeation is complete. The compounds or
mixtures commonly used in chemical closets are of two general kinds:
First, those in which some coal-tar product or other oily disinfectant is
used to destroy germs and deodorize, leaving the solids little changed in
form; second, those of the caustic class that dissolve the solids, which,
if of sufficient strength and permeating every portion, should destroy
most if not all bacterial life. Not infrequently the chemical solution is
intended to accomplish disinfection, deodorization, and reduction to a
liquid or semiliquid state.
[5] Annual Report, Mass. State Board of Health, 1914, p. 727.
[Illustration: Fig. 15.--Chemical closet. _A_, Water-tight sheet-metal
container; _B_, metal or wooden cabinet; _C_, wooden or composition seat
ring; _D_, hinged cover; _E_, 3 or 4 inch ventilating flue extending 18
inches above roof or to a chimney; _F_, air inlets.]
[Illustration: Fig. 16.--Chemical tank closet. _A_, Tank, 2 feet 3 inches
by 4 feet 2 inches, 5/64-inch iron, seams welded, capacity 125 gallons;
_B_, 14-inch covered opening for recharging and emptying tank; _C_,
12-inch galvanized sheet-metal tube; _D_, 4-inch sheet-metal ventilating
pipe extending above ridge-pole or to a chimney; _E_, agitator or paddle.]
A simple type of chemical closet is shown in figure 15, and the essential
features are indicated in the notation. These closets with vent pipe and
appurtenances, ready for setting up, retail for $20 and upward. A chemical
tank closet, retailing for about $80 per seat, is shown in figure 16.
The Department of Agriculture occasionally receives complaints from people
who have installed chemical closets, usually on the score of odors or the
cost of chemicals.