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Presentation
for the winter-workshop 'Infrastructures of Consumption & the
Environment'
Wageningen,
November 27, 2000, 11.50-12.10
I
would like to tell you a story. A story about a dream and about the
collapse of dreams. It is a personal story, but it is also the story of a
housing project for which building and living in an ecological responsible
way was the main starting point. The project is called The Green Roof (www.groenedak.nl)
It
all started in 1989. Eventually, in 1993, 66 houses were built. I have
been a participant of The Green Roof since its start and I have lived
there until 1998.
Ever
since we started thinking about the project, the use of building material
and the consumption of water and energy has had our attention.
Personally I have been heavily involved in the development of ecological
responsible ways of using water. We developed some extraordinary
experiments, some of which are only used in parts of the project.
Our main starting point was the idea that taking care for the environment
is an individual
responsibility. We believed that only a change of conduct and the use
of small-scale technology would finally result in a better environment.
From this starting point two experiments were developed. Both were based
on the idea of independence
of large-scale systems.
The
experiments were:
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Collection
of rainwater and its utilisation in flush toilets (12 dwellings).
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Composting
toilets and grey water purification systems in 10 dwellings. These
dwellings do not have a connection to the sewerage system.
Two
measures were supposed to reduce our dependence on large-scale systems:
It
is now the year 2000. We have had seven years of experience with different
systems. Over the years my own views towards small-scale practises have
changed considerably.
We have had serious technical problems. These problems were partly due to
lack of money. So these could be remedied.
But there have also been doubts.
Doubts about the environmental benefits of the systems we used. I will
explain some of the experiments to you and cast some light on the doubts
that were raised.
Rainwater
never gets lost
We
never had any technical problems with the rain water system. The savings
on drinking water that can be reached with this system are around 30%. The
rainwater is only used to flush the toilets. Thirty percent is rather lot,
but we still have to raise the question whether the installation of rain
water systems is justified by the environmental benefits.
This system uses two times more electricity than the regular system in
which drinking water is used (0,4 versus 0,8 kWh/m3). The reason for this
is the small scale of the rain water system. Small pumps require
relatively more electricity. Besides, the system relatively takes much
more material to install it than other large collective systems. At the
level of an individual house there is a huge difference: in stead of one
water pipe the rainwater system needs a double system of pipes, a barrel,
a pump, en appendages.
Free-flow rain water systems (without a pump) use less electricity and
require less technical equipment. But they are hard to install in a
building. Consequently the barrel is much smaller so less drinking water
can be replaced by rainwater.
The first time I became critical about these systems was after I
discovered that several drinking water companies had become interested in
large-scale dual water systems. Why try to catch rainwater on a small
scale when you are pumping anyway? Rainwater never gets lost. It falls
down and can be collected where is goes, in surface water or in ground
water, and with limited means. These large-scale systems seemed to be more
efficient.
My
conclusion:
Apart from the problem of desiccation (verdroging) of wetlands and natural
reserves, the existing drinking water distribution system seems to have
little disadvantages. Individual rainwater systems can party solve some
problems, but replace them by an energy problem. This is especially
problematic, because the threat to the environment when it comes to energy
is much larger. When we really want to do something to the environmental
impacts of drinking water production it is probably better to start
using surface water instead of ground water.
The
sewerage system is not so bad after all.
One
of our experiments concerned the installation of composting toilets in ten
houses, using two systems. These composting toilets were important to us.
We had been careful with water and electricity and managed to do quite
well in our old houses, even without special equipment. But the reduction
of wastewater is simply not possible without the use of technology.
We
started experimenting with composting toilets, because:
-
There
is no loss of drinking water
-
There
is no pollution and the problem of polluting sewerage overflows is
ended
-
There
is no loss of organic material
When
it comes to these three issues the composting toilets were indeed
successful.
But
still the experiment was a total
failure. Next week the housing corporation will remove the whole
system. The biggest problem will be how to remove the compact mixture of
straw, organic waste and the faeces of the 5 habitants that lived there in
the past 7 years, as this mixture never became compost. We have tried everything:
different carbon addings, different aeration, digging in the heap,
stabbing holes in it with sticks, leaving worm to live in it, but it was
dirt that could not be handled in any way.
The system needed a lot of maintenance and this was a tough and dirty,
maybe even dangerous job. After 7 years of trying and hoping for
improvement people gave up and nobody wants to do it anymore.
Another disadvantage of the
composting toilets is the amount of electricity that is needed to operate
the ventilator. It uses at least 1 kWh a day, when put at its minimum
requierement (40 Watt). When you know that the savings of drinking water
with this system is about 120 litres of drinking water per day, it means
that these savings cost about 7 to 8 kWh for every m3. Turning seawater
into drinking water costs less energy!
Maybe the problems with the compost toilets have technical reasons.
Maybe we did something wrong. But I think that trying to compost in a
low-tech manner inevitably leads to problems.
The experiment with sewerage-free housing has failed. Ordinary toilets
will be installed with a connection to the sewerage system. We may find
some comfort in the idea that The Netherlands does not have a serious
problem with drinking water after all. And that there is too much manure
in the country anyway, and that wastewater purification plants take out
phosphates more and more.
The greywater purification system seems to function really well. But since
there are no composting toilets any more and the ‘black water’ flows
into the sewerage system, we might as well let the grey water into the
sewerage system. It will again save us some kilowatt-hours.
From
water to energy
I
left The Green Roof two years ago and I live now in an old apartment. I do
not experiment with water anymore.
I still think individual
responsibility is important. My belief that independence
of large-scale systems leads to environmentally sound solutions has
vanished. A year ago I have installed 6 solar panels, connected to the
grid.
In my view there is a fundamental difference between the collection water
and solar energy. Water does not get
lost very easy, it goes somewhere anyway. The energy from the sun does
get lost when we do not catch it through solar panels or solar
collectors. The same goes for wind energy.
Collecting water can be done more efficiently on a large scale. But the
collection of solar energy and wind energy has
to be done on a small scale and at least decentralised. This is the
only way it can work.
With
my 6 solar panels, the use of energy saving light bulbs, a laptop
computer, a type A refrigerator and a central heating system that shuts
itself off I will hopefully be self sufficient this year. Still only about
5 - 10 % of the electricity I produce is simultaneously used.
Yes,
I do fantasise about installing a rainwater system. Something that is
probably impossible in my apartment. When the moment comes to make my
fantasy come true, it will not be for environmental reasons, but because I
still harbour my dreams about self-sufficiency.
Michèl
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