8
Theory of composting toilets
There are 4 factors that affect the efficiency of a
composting toilet:
Moisture
In optimum conditions, the composting material has the
consistency of a well-wrung sponge – about 45% to 70%
moisture. When below 45%, there is not sufficient
moisture for the microorganisms to function, and above
70%, saturated conditions begin to develop, and oxygen
depletion becomes a limiting factor.
Maintaining moisture
Since the BTS 33 does not have a heater, the
moisture content needs to be maintained by
proper ventilation, addition of proper mulch, and
a good flow from the drain tube.
Temperature
The typical temperature range for most composting
toilets is 68°F to 112°F. Lower temperatures result in
a moldering process that takes a significantly longer
period of time to compost and therefore requires a
much larger composting chamber.
Maintaining temperature
Since the BTS 33 does not have a heater, the
temperature needs to be maintained by
maintaining ambient room temperature and by
the natural heat generated during the
composting process. Therefore, ambient room
temperature of at least 64°F needs to be
maintained during periods while the toilet is
being used.
Aeration
The aerobic organisms responsible for the
composting process require free atmospheric or
molecular oxygen to survive. Without oxygen, they
will die and be replaced by anaerobic
microorganisms that will slow the composting
process and generate odors. For composting toilets
to work most effectively, the materials being
composted should be unsaturated with liquids, and
have a loose texture to allow air to circulate freely
within the pile.
Maintaining aeration
Your BTS 33 includes a 12V fan and will assist
in aeration. Additionally, maximum aeration can
be achieved by:
1. Keeping the product inside the composting
chamber in a loamy consistency.
2. Proper installation of the ventilation pipe. Keep
in mind that the addition of any angles in the
vent pipe will reduce the airflow.
3. Ensure a good flow of air to the bathroom from
the living area.
4. Make sure there are no other air drawing
appliances; e.g. furnace nearby. They would
interfere with the air flow.
Carbon to Nitrogen ratio (C:N)
Microorganisms require digestible carbon as an
energy source for growth, and nitrogen and other
nutrients for protein synthesis. When measured on
a dry weight basis, an optimum C:N ratio for aerobic
bacteria is about 25:1.
Maintaining C:N
A small handful of starter mulch per person per
day or approximately 1 quart per person every
week is a good rule of thumb to maintain a
helpful C:N ratio, absorb excess moisture, and
maintain pores in the composting material.
Use and Care
To ensure that your BTS 33 will operate at its peak
potential and that the end product (called Humus)
will be hygienically safe to handle and to recycle on
your property, pay close attention to the following
directions.
Precautions
•
Always observe good biohazard safety
practices when working on the BTS 33.
Wear goggles, disposable rubber gloves and
clothing to prevent contact with unprocessed
human excrement. Unprocessed human
excrement contains potentially dangerous
human pathogens, which may cause illness.
•
NEVER put cigarettes or other burning or
glowing materials into your BTS 33!
•
Do not put sanitary napkins, food scraps, or
animal excrement in your BTS 33. Your BTS
33 is intended for the disposal of human
urine, fecal matter and toilet paper ONLY.
Introduction of other materials may hinder
the composting process or decrease the
capacity of your toilet
Adding starter mulch
It is very important to add starter mulch to your toilet
on a regular basis in order to promote aeration, add
carbon and to improve the compost's ability to
absorb liquid. During regular operation add a
minimum of 1 quart of starter mulch per week per
person. Therefore, one should make it a habit to add
about 1/2 cup of starter material after each fecal
use.
Approved mulches
Use of only BioLet Toilet Systems approved
starter mulches is recommended. Approved
