What do NEDLAW active Living Walls biofilters look like?
Is anyone else trying this approach?
Could native plants be used in the system?
How long do the plants survive in the space?
Are pesticides used in the wall?
How much maintenance does a Living Wall require?
How good is air quality from an active Living Wall?
How well does the system work?
What’s the difference between installing an active Living Wall and simply putting a large number of plants in your space?
What are the options for making a Living Wall active?
How large should the Living Wall be for a typical building?
What do NEDLAW active Living Walls biofilters look like?
A wall covered in plants, our system is essentially vertical hydroponics. Water
from a basin planting is lifted by a pump system to the top and flows back through
the interior of the plant wall circulating through a closed water loop system.
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Is anyone else trying this approach?
To the best of our knowledge, the NEDLAW patented system is the only one
to use plant walls as biofilters to control indoor air quality.
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Could native plants be used in the system?
Some native plants may be present. However, most native plants would not survive
well indoors. Plants adapt to their local climate and, as such, plants from
northern climates generally require the different seasons to grow properly.
For most native plants to survive indoors, the climate in the wall would have
to mimic these seasons, making routine use of the space difficult and its performance
irregular.
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How long do the plants survive in the space?
We expect about 90% survival of the plants each year; but this is largely
dependent on the choice of plants and local conditions.
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Are pesticides used in the wall?
We use only methods that can be considered organic to control pests in our walls;
we emphasize management practices and biological controls such as predators.
So-called pests such as white flies, fungus gnats, spider mites and their respective
predator species are necessary, even desirable. They contribute to the ecosystem’s
species diversity and ecological stability.
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How much maintenance does a Living Wall require?
We carry out scheduled maintenance on our Living Walls every month. Some clients
choose more frequent visits based upon their unique conditions.
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How good is air quality from an active Living Wall?
The air quality of a space relying almost entirely on active Living Walls is
as good as, or better than, similar indoor spaces relying on sophisticated
ventilation systems that replace the building air up to six times per hour.
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How well does the system work?
During studies at the University of Guelph, we released into the wall very
low concentrations of some common indoor pollutants to measure the system’s
potential as a filter. The chemicals were formaldehyde, toluene and trichloroethylene
(TCE). These were selected to represent the wide range of chemicals with which
the system would need to deal. Formaldehyde is very soluble in water and readily
metabolized by bacteria and higher plants. Toluene is slightly soluble and degraded
by a select microbial population. TCE is relatively insoluble and resistant
to biological degradation.
A single pass through the Living Wall removed up to 80% of the formaldehyde,
50% of the toluene and 10% of TCE. These numbers are incredibly impressive,
particularly when you consider that the filter is only 5 cm thick. Concentrations
of toluene and formaldehyde in the aquatic system did not increase during the
four-week experiment, suggesting that these materials were readily metabolized.
TCE levels in the aquatic system initially did increase slightly, but then plateaued,
suggesting a possible capability to degrade this compound. Even before
the challenge, we knew that two to three percent of the bacteria present had
the ability to break down VOCs.
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What’s the difference between installing an active Living Wall
and simply putting a large number of plants in your space?
Some suggest that plants may remove VOCs from their surrounding environment.
However, there is very little available data to support this claim. Most studies
which find any VOC removal with potted plants suggest it is in the potting soil
(where the beneficial microbes live), not the green plant, where the breakdown
occurs. Others believe that even if plants can clean the air, they could only
clean a very thin layer of air immediately around their leaves. When a plant
is simply placed on a desk or even in a grouping on a wall, the typical low
rates of air movement around it would limit its impact on the air, in the space
as a whole. By actively drawing air through NEDLAW Living Walls™, we force pollutants
to the root zone where real breakdown can occur.
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What are the options for making a Living Wall active?
There are three ways air can be drawn through the Living Wall to make it active:
The most effective way is for the wall to be designed as an alternative return-air
path back to the HVAC. The air, which is normally drawn from the space, is first
cleansed as it passes through the wall and then is disseminated through the space
by the HVAC. Ideally a bypass is integrated into the design so that air can
be drawn from the space without passing through the wall (for periods of free
cooling, wall establishment or wall maintenance).
The second approach is to build fans right into the wall so it functions as
a stand-alone unit; separate from the building’s HVAC. Although this works
well, it is not as effective as the first method since it has a much more localized
effect.
The third method is a hybrid of the first two. The Living Wall has its own
fan system but it also has a duct system to better diffuse air through the space.
We can help select which scenario would work best in your space.
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How large should the Living Wall be for a typical building?
Although there are many factors to be considered, the quickest and easiest estimate
for sizing a Living Wall is one square metre of active Living Wall to meet
the needs of 100 square metres of floor space.
Alternatively, the wall can be sized on the basis of the amount that needs
to be drawn through the space’s return air system. Our designers can work
with you to determine this way of sizing the wall.
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