Explaining Ventilation

The question often arises, does the C-Head or BoonJon need to be ventilated? More often than not, it
does not. Ventilation is used primarily to remove the moisture that evaporates off of the solid waste and
control the buildup of condensation inside the toilet. It can also function to remove the smell from non-
urine diverting composting toilet systems which is common for them. Sewage odor is not an issue with
effective urine diverting toilets in general and the C-Head/BoonJon specifically. Understanding how the
toilet works will explain why this is so. Basically the C-Head/BoonJon system takes the solid waste and
covers it with a fine medium by churning or rolling the waste in the medium using a wave-like action.
See video. This minimizes the surface area of the solid waste that is emitting the odor and wicks the
moisture off the surface, removing the smell instantly. There are a
variety of mediums; saw dusts, fine
wood shavings, peat moss and corncob pulp are just a few, that will remove any sewage smell from the
solid waste by simply absorbing the moisture from the surface of the waste.

Other “urine diverting” systems mash the solid waste into the medium much like a dough mixer in an
effort to speed up the composting process. Whether this technique is successful in speeding up the
breakdown process depends on many other factors such as climate, moisture content, temperature, type
of medium, pH, etc. In any case, the waste is never composted to the point of being safe to handle. In
the process of kneading the waste into the medium, they increase the surface area which produces more
vapor and thus requires ventilation to remove the excess moisture and smell. On the positive side, it
does make the waste less recognizable but the offset cost is mandatory ventilation. Since these toilets
dominate the compact composting toilet market, the impression is given that ventilation is required on all
composting toilets, which is not the case. Unless you are in a hurry to compost the waste for some usable
purpose or are totally put off by the sight of medium covered waste, ventilation isn’t normally necessary.
With respect to the toilet itself, the primary function and need for most users is for it to be able to store
the waste securely and without any obnoxious smell until it can be either discarded or composted further
at some other location using a composting bin or mound.

Ventilation would usually be a benefit for the system unless it requires an expensive, complicated
installation or causes esthetic or safety issues, in which case leaving the toilet unvented would be
preferable. If odor is an issue, it can be corrected usually by changing the type of medium being used. If
condensation is an issue, it normally can be corrected by just emptying the collection container more
often as the condensation becomes noticeable, which in the case of the C-Head/BoonJon is simple to do.
Condensation can also be remedied by adding and mixing a drying agent such as equine pine pellets to
the medium.

Ventilating the C-Head/BoonJon can be done by inserting a vent pipe (supplied) through the back panel
or side of the housing to draw air out of the inside, and moisture along with it. It is more effective to
have the vent pipe go into the back panel at the center and into the solid waste collection container
directly (as shown in the directions), so that it is drawing out the air directly over the waste. If a docking
cabinet is being used, then the back panel on the C-Head/BoonJon housing can be removed completely
and the base of the docking cabinet can be ventilated through piping to the outside to draw out the air
in the toilet housing.

In the case of a mobile installation, such as a boat or RV, the entire system, including the vent hood
adapter can be daisy chained together so that a single fan can draw out the moisture from the toilet
housing and the disposable collection container. Briefly, the
vent hood adapter is an appliance that locks
onto the top of a disposable 5-gallon bucket where the solid waste from the toilet is stored until it can be
disposed of or transferred to a composting setup. Drawings are shown in the instructions as suggestions of
how to accomplish this. All installations are unique and some engineering by the owner is going to be

Ventilation can be in the form of passive or active ventilation. Passive ventilation uses the venturi effect,
such as cowls, or other drafting appliances noted in the venting instructions in the owner’s manual. Active
ventilation would be either an in-line fan that could be located along the hose itself or connected to the
side of the toilet housing or at the end of the vent hose or pipe, such as a Nicro solar vent. A simple
reducer can be made using commonly available PVC pipe fittings that will connect the 1 ¼” hose
(supplied) to the 3” flange of the solar vent.