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English summary
Within the framework of the “Village for Green Research” at Folkecenter for
Renewable Energy (FC), various forms of green waste water treatment have been
tested since 1988. Today three different plants exist (see figure 2.2.1) which can
work independently of each other, while they are, however, connected to each
other so that they can be used at the same time.
Household waste water from 20 person equivalents (PE, see enclosure C) and from
the about 4000 m 2 buildings is finally led to the root zone plant which is the biggest
plant in the area. The two test plants in the greenhouse make it possible to carry out
several tests and development of plants for household waste water treatment
without taking into account if a sufficient efficiency during the tests is obtained so
that the cleaned waste water can be led to the recipient (SkibstedFjord).
In 1988, the first demonstration plant was established as a decentralized solution
model for waste water cleaning by utilization of ecological cleaning principles and
a minimum of energy consumption. The composition of the plant has been inspired
by the so-called “Vermont-model”. The plant is based on the utilization of energy
from the sun for removal of nutritive salts as e.g. phosphates and nitrates through
bacterial decomposition and absorption in plant tissue. In co-operation with
Botanical Institute, Aarhus University, analysis of the waste water were made
before, during and after the treatment in the plant. The plant was established in
greenhouse 1 and 2 (see plan, figure 2.2.1), today, however, only the part in
greenhouse 1 exists.
In connection with new building, a root zone plant for 100 PE with fascines was
established. The plant is projected by Jørgen Løgstrup, TransForm, Dansk Rodzone
Teknik.
As the latest plant at FC, the plant of “Water for Life” was established in the
renovated greenhouse 2 (figure 2.5.4.2) in 1999. The plant is inspired by the
experience which has been gained at FC after 10 years of test operation of “green”
waste water treatment plants. The plant is dimensioned as a family waste water
treatment plant from 4 to 6 PE. Two parallel lines have been established, the first
being considered as the family line of 4 m 3 total volume, and the second being
called the guest plant. During daily operation about 80% of the waste water is
running through the family line.
The plant consists of several different steps having different functions (figure
2.5.1). From the inlet cesspool the waste water (mixture of black and grey) is
pumped to the first step which is a closed aerobic phase (figure 2.5.2.1). There is a
shared 1000 litres container where the water is aerated heavily with atmospheric
air. The polluted air is led to the ground filter which is a kind of soil filter. The
surplus water is led on to the next step which is an open aerobic phase consisting of
6 plastic barrels in the first and four in the second line. The containers are planted
with about 20 different plants. The water is aerated from the bottom. Next step is a
sludge pond which in both lines is a 1000 litres container. The sludge is led to a
sludge bed while the overflow is running on to biofilters, four 200 litres plastic
barrels in the first line and three in the second line. Finally the water ends up in the
demonstration basin from where it is led to two production basins which are not
included in the existing test construction.
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