In general, chemical closets should be used only where there are
elderly or infirm people unable to get outdoors, particularly in
winter-time. In some localities their use is forbidden by law because
of improper maintenance. Strict adherence to the manufacturer's
directions for making the installation is necessary to obtain
satisfactory service. The chief advantage of chemical closets is that
they may be within or adjoining the house and used without regard
to soil or ground-water conditions. The caustic chemicals required,
if used properly, reduce the quantity of solid matter by liquefying
action, disinfect and deodorize the contents, and lessen danger from
flies. Disadvantages are the cost of the chemicals and necessity for
careful and constant maintenance.
The chemical-tank closet is generally recommended rather than the
dry-type chemical closet. Three variations of tanks are available
commercially. One type contains a clean-out opening in the top of the
tank, through which the contents are removed by pumping or bailing.
The second type has, in addition to a clean-out opening, a drain valve
at the bottom, which is operated by a handle extending to a clean-out
opening, so that gravity drainage of the tank is possible. The third
type is self-draining; as the excreta are added an equal volume of
liquid is spilled out the overflow. The solid matter must be removed
manually or through the sludge drain.
The last-mentioned type requires frequent addition of chemicals, and
the others are recharged after each emptying. The presence of odor is
an indication of insufficient chemical or of the need for emptying
and recharging. The same precautions apply to selecting an area for
disposing of the tank wastes as to disposing of the materials removed
from cesspools.[11] Since the contents of chemical closets are caustic,
they may kill vegetation with which they come in contact.
[11] For disposal methods in tight soils, see p. 16.
The dry-type chemical closet is cheap, simple, and easy to install
but requires frequent emptying. Pine tar and coal tar will accomplish
only partial disinfection and deodorization, but caustic disinfectants
produce liquefication in addition if used in sufficient quantities.
The caustic chemicals may cause burns if the receptacle is too full or
if spilled where they come in contact with the body.
This form of closet is more of an expedient than a permanent
installation, and daily care is necessary to prevent the development of
insanitary conditions.