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INTRODUCTION
The aim of this section is to give you an overview of the use of a Waterless Composting Toilet and in
particular a Rota-Loo. It will cover the composting process, and how Rota-Loo works to ensure correct
composting and what you will need to consider in the installation of your Rota-Loo.
THE COMPOSTING PROCESS
Composting is nature’s recycling process. It is how organic material is broken down by micro-organisms to
produce a rich product called Humus, an organic fertilizer, mulch and soil conditioner made from decayed
organic material. Because human waste is an organic material, it can be composted to produce humus.
The quality of the humus from a Waterless Composting Toilet (WCT) will be influenced by the design and
installation, the materials you are adding and climatic conditions. In a correctly installed and maintained
Rota-Loo you can create humus which is soil like in texture and smell.
There are two main groups of bacteria that can be used in
composting. Aerobic (requires oxygen) and anaerobic (no oxygen
required). Aerobic bacteria processes material faster and with
significantly less odorous gases than anaerobic bacteria. If the
material in the bin gets too wet or compacted down, air (oxygen)
cannot circulate through the pile and aerobic bacteria will die out
and be replaced by anaerobic bacteria. Anaerobic bacteria are
responsible for creating odours (nitrous oxide or rotten egg gas”)
which are associated with some composting and septic systems.
To maintain aerobic decomposition, it is important to keep the moisture containment of the material below
70%, and ideally between 50% and 60%. As fecal matter is 70-80% moisture and urine about 95%, for a
WCT to work correctly there must be a method to separate the liquids from the solids.
The heat of the compost pile is also very important in composting. Depending on the temperature there
will be different dominant bacteria groups:
• Below 5°C very little activity takes place.
• From 6°C to 20°C – Psychrophilic,
• From 21°C to 45°C - Mesophilic,
• From 46°C - 71°C Thermophilic.
From the graph shown (from AS1546.2) the time for
organic material to be composted is very dependent
on the temperature. Heat will be generated by the
bacterial activity, but holding that heat and adding
to it is important for effective operation of a
waterless composting toilet system.
A realistic operation is to encourage the Mesophilic
bacteria by maintaining warmth in the WCT and
adding bulking materials to promote a loose textured
pile that allows good air flow (oxygen supply). The Carbon-Nitrogen ratio (C/N) is a further important
aspect in composting. Carbon and Nitrogen is the food required by micro organisms. The C/N Ratio can
vary from 40:1 to 25:1, but in general terms you need a lot of Carbon to a small amount of Nitrogen so for
optimum efficiency some high carbon bulking materials should be added.
250
200
150
100
50
0
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44
Compost Temperature
Day
s to C
ompos
t
Days of Composting with relation to temperature
To learn more about naturally disposal of human
waste and how to improve the composting
process and end product, the book “The Humanure
Handbook” by Joseph Jenkins is a useful resource.
