is a compost toilet not a compost toilet?
Compost toilets rely on the natural breakdown of deposits in situ rather than
collecting waste for it to be processed elsewhere. Thunderboxes require no
direct services, so can be built virtually anywhere. The deposits are no longer
"waste" and over time can be returned to the soil. This gives users
a sense of connectedness to the bigger picture rather than a "private
many people will a toilet serve?
There is usually a "rush hour" in the mornings, so the more seats
the better as numbers rise. Festival/local authority guidelines stipulate
one toilet/100. Refugee camps recommend one/30! Neither of these models are
ideal! We suggest 1/15 maximum for a single and 2/50 maximum for a double.
Your customer experience will be proportionate to queue time!
often will I have to empty the container and how?
How big is the average poo?! With deposit, sawdust, paper and maybe a little
liquid, one person will produce a about a litre/day if that person is present
for the full 24hr period. Day visitors will need more urinal facilities and
leave much less solids. So our 1000L IBC's will last 1000 person days if it
all happened at once! (which is what happens at festivals!) However, because
of "critical mass," far greater capacity is achieved by the composting
down of the deposits as they arrive. Strong aeration created by our airflow
system further reduces bulk by de-hydration and improved composting. Due to
this process, 1 composting tank lasts our family of 6 around 500 days, whereas
we would fill a wheelie bin in 25 days!
Deposits arrive via the urine separator chute which fits a aperture in the
top of the IBC. This is what we have to empty out through. It's big enough
for a regular spade, and although it's quite a tight working space we find
half an hour is all that is needed, which after a year of waiting is not much
I have to handle un-composted material?
No! Obviously there are environmental health implications when dealing with
raw excrement, so the aeration of containers is fundamental to small batch
composting. This is why we like IBC's so much; you're always a safe distance
from the deposits and the compost process occurs in situ.
it true you can't pee in a compost loo?
Too much liquid means the compost will go anaerobic (lacking oxygen) and different
bacteria will result. These bacteria give off methane and other offensive
smells and make the whole process very unpleasant! A urine separator is the
answer, thereby diverting urine away from the deposit container. These are
more easily used by women than men as they are generally designed for the
sitting position. However men can aim more accurately but do have to be instructed/educated
to do so! Either that or sit down to pee. The male pee issue is important
as too "meny!" will result in anaerobic conditions, so signs/instructions/alternative
urinal facilities are essential. It's really a cultural thing which we all
need to work at, especially the boys!
does the urine go?
The pee is separated off by the urine separator under the seat and is removed
by a drainage pipe. From past experience, we have developed a separator with
a large diameter exit to prevent blockages. The pipe can be directed to a
soak-a-way on suitable soils, a straw bale or a liquids container. The latter
can be exploited to transfer pee as a fertiliser to compost heaps (useful
on an allotment site) but involves carrying liquids (always heavy!) Urine
is pretty much benign as a waste product on its own. A healthy soil, ideally
containing lots of carbon(woodland/hedge soils) is a good soak-a-way but if
the soil is heavy or with restricted drainage, a small brick/stone filled
hole may be necessary. On very sensitive sites or very close to rivers, containment
and carrying may be the only option. The Environment Agency generally do not
have a problem with pee soaking-a-way as long as it's just pee. Once pee and
poo mix this is known as" black water" and this does pose a danger
to health and the environment and should not be drained off into soil.
Do I need to use sawdust?
Any organic matter such as chopped hay or straw will also work. To create
the best conditions for good composting it's important to get the chemical
composition right. This sounds technical but actually all that is needed is
a good nitrogen:carbon balance. Deposits are the nitrogen part, so by adding
a carbon containing "soak," such as sawdust or shavings helps balance
the chemistry. Covering the deposits also helps prevent smells and fly activity
in the chamber. To achieve the ideal 1:30 ratio of nitrogen to carbon, only
a small quantity of sawdust is necessary. Too much will slow down composting
and fill the container more quickly.
Do compost toilets smell?
They shouldn't do but have a reputation because of poor practise. Two things
are vital, low moisture content and aeration. Low moisture content is achieved
using a urine separator and educating men! Aeration is achieved using a good
ventilation system which should ideally dehydrate the deposits as they arrive.
Occasionally turning the main tank will really help the composting process
but is not essential. Our large flue and effective seals ensures excellent
"draw" thereby assisting aeration and eliminating smells. Eco-cubes
are available to breakdown bacteria associated with urine smells and can be
placed in the urine separator.
How about delivery and installation?
Thunderboxes come as a DIY kit with full assembly instructions and all fixings
needed - much like a garden shed - all you need is a cordless screwdriver.
However, we also provide an installation and follow up maintenance service.
To save on costs, you are welcome to collect your Thunderbox from us here
in Devon if you're down this way, otherwise we charge a bit extra for delivery
depending on where you are based.
What maintenance is needed?
Apart from routine cleaning, very little! With low levels of input (ie a small
family), one tank can last up to 2 years before you may need to change it
or would like some compost! Unlike wheelie bins which would fill within a
month with the same level of use. That's a lot of wheelie bins! Most of our
Thunderboxes are designed so that the composting tank can be shimmied out
when full, although the double unit will need to be dismantled (hang onto
those installation instructions!) and then set up around an empty container.
The full one can then be sealed with a breathable membrane, left in a corner
somewhere and turned occasionally until the compost is ready to use. If you
lack the time or practical confidence, we can come and do this for you, although
a very small percentage of our clients have needed this level of service.
How long do I have to leave the compost
before its safe?
Allowing the deposits to compost for a year renders the compost safe to use.
Going for two years allows the sawdust or shavings to break down even further
thereby producing really nice soil -like compost.
Where can I use the compost...are there regulations?
There are no specific regulations regarding small batches of humanure compost,
however the Environment Agency or even Environmental Health may take an interest
in your operations via the Planning system. Full containment and good long
composting periods ensure an easier life! We use most of the compost we produce
on fruit trees and roses! Even running a hire business we produce less than
1000L of compost a year and that makes our trees and roses very happy. If
we use any on our food growing areas, we tend to use our own humanure as we
know what goes into it!
Can I put loo paper, the inner cardboard roll or nappies down there?
Paper, cardboard and even kitchen compost can all go in. The paper and cardboard
are useful sources of carbon, so assist the nitrogen/carbon ratio. Nappies
on the other hand are not bio-degradable; in our experience, not even the
bio-degradable ones! Other sanitary waste is not desirable either so a sanitary
deposit bin is a good addition to the housekeeping of any compost loo.
Will I need planning permission?
Not for a Thunderbox in general as they are moveable structures and have always
been designed so. However, if you are changing the use of a field or even
your garden to a camp site for more than 28 days, you may well need Planning
Permission. In that process, the planners may well want detailed information
on your facilities including the toilet. We've helped a lot of folks through
this process and can provide Thunderbox plans by arrangement. Your best bet
is a planning consultant if you are setting up a business that requires planning
permission to ensure the best possible advice.
What laws and regulations apply to compost toilets?
The law is rather vague on compost toilets specifically. However, we have
had our system of composting approved as a low risk operation by the Environment
and have built a code of practise with them. Moving waste to a separate site
for composting will require a waste handlers licence. Building regulations
and Planning laws may also apply as above. Environmental Health may get interested
in your operations if you do not fully contain waste for composting or prevent
smelly deposits...See smells above and rats below!
Do I have to dig holes or other ground works?
Not with Thunderboxes! A reasonably flat site is all that is needed, approximately
5.5m x 2m allowing for access. A small soak-a-way may be needed for the urine
What do kids think of compost toilets?
Kids can be a bit scared of the deep dark hole some compost toilets have.
Anything out of the ordinary can also cause concern to children. However,
we've supplied Thunderboxes to several nurseries and forest schools and find
that kids generally love our toilets and often warm to them as a sort of wendy
house, which may not always be desirable as sometimes the sawdust becomes
an irresistible play material! The only thing we suggest to help kids or advise
their parents the first time they use one, is to sit back to avoid depositing
in the urine separator. If toddlers are using it, then the addition of a toilet
training seat will help achieve this. Some colourful pictures/cartoon characters
may also have a calming effect!
What about flies and rats?
Closing the lid is important to prevent flies entering but is not always completely
effective. The presence of flies usually indicates a lack of sawdust in the
right places! A quick dusting usually helps. Little tiny fruit flies can set
up camp in the box occasionally and again, a sawdust dusting is the answer.
Rats are another thing altogether! Human deposits are chocolate to rats...think
sewers! Super tight seals and FULL containment is vital. Apart from being
an unpleasant and potentially risky experience (and one which is necessary
with some other makes of 'compost' toilet), tipping fresh deposits into any
open or enterable container will soon bring the rats. The solution is prevention
from the beginning because once you've got them they are very difficult and
brutal to remove.
What cleaning products are OK to use in compost toilets?
A compost toilet relies on naturally occurring bacteria and fungi to breakdown
the deposits. Therefore conventional cleaning products that "Kill all
known germs dead!" are not welcome in the compost toilet world. In other
words, no bleach or serious chemical cleaners. Benign cleaning products such
as Ecover or similar will effectively clean but not harm the composting process.
Is lighting important?
Lighting is important, particularly where the toilet will be used overnight.
There are a number of solar shed lights quite widely available now that are
ideal. They require no specific electrical supply and generally work fine
in the summer. A timed light is more useful in the winter to conserve the
limited charge available in the darker winter months.
What about hand washing?
Well of course but how? It's an important consideration and often difficult
in remote situations. Gutters can be fitted to feed barrels of rain water
or specific barrels can be added, perhaps with a rustic wash stand? (ask for
details!) Cleansing gels can be used if water supply is an issue but are often
rather "chemical" which we've always felt a bit at odds with a "natural"
toilet! We can supply dispensers and bottles filled with an Aloe vera based
natural sanitizer (ask for details). However, if a water supply is available
we can provide a 'sink single' based on a double Thunderbox, with a sink instead
of a second seat.
And finally...........Why a Thunderbox!
Simply the best! To cover all the questions above, which are not Thunderbox
specific, you'll either need a full-on vault system double header or.........!