1) When soil around the roots of plants is wet and
impacted the conditions are anaerobic because not
much air can get into this soil. But it is in this
anaerobic condition that Klebsiella spp. fixes
nitrogen (because it cannot fix nitrogen in aero-
bic conditions.)
2) But this situation is partially self-defeating.
That is because, when there is very little air in
the soil of the rhizosphere, there is also very
little nitrogen and thus very little nitrogen that
can be fixed.
3)
When air is present, as in aerobic soil, then the
nitrogenase of Klebsiella is severely hampered by
the presence of oxygen. While Klebsiella can sur-
vive in oxygenated soil, it cannot fix nitrogen
in that condition. Thus there is no benefit from
adding air to the soil for the purpose of enhancing
nitrogen fixation.
4)
But the case is different if nitrogen alone is
added. Then there is ample nitrogen available for
Klebsiella to fix.
5)
But there is another impediment. The roots of plants
and trees release 20 % of the total carbohydrate they
produce into the rhyzosphere to nourish nitrogen
fixing bacteria. Because the bacteria are ineffecient
(especially Azobacter), that 20 % doesn't go very
far in satisfying the nitrogen requirement of plants.)
6)
However, in a biogas digester at the end of the first
period, there is a large amount of monosaccharide that
can be used to nourish relatively efficient Klebsiella,
AND it is possible to sparge nitrogen alone into the
digester to supply the nitrogen need of this micro-
organism. Since nitrogen alone (and not air with oxygen)
can be injected, there is no fear of destroying the
necessary anaerobic conditions.
( But this may not be the best way. Later c.f.
using copper and biogas to produce N2.)
Klebsiella
spp.,Clostridium spp. Bacillus polymyxa,
Desulfovibrio
desulfuricans, Arcromobacter spp. are
microorganisms
that fix nitrogen in anaerobic conditions
and are a useful
source of fertilizer nitrogen both in
their natural
environment as well as in artificial
conditions.
The present exposition sets forth ways in
which
Each gram of carbohydrate contains 4
Kcal of energy. Thus each gram
of fixed N requires 40 Kcal of carbohydrate
energy.
Multiplying by 1000 to get the
energy required for a kilogram of N
fixed.
1 Kg of N requires 40,000 Kcal
Thus Klebsiella sp. is less than 1/2 as efficient as Bosch-Haber
HOWEVER,
The energy for Klebsiella sp. is derived from handy
farm waste
Side note: Klebsiella sp. can live in aerobic conditions, but it cannot
fix nitrogen where oxygen is present. ( It should
do well in the kind
of anaerobic condition in which nitrogen is present
but not oxygen.)
It has a bad or mediocre reputation because
it does not fix much
nitrogen in a biogas digester.
Obiter dicta: There are some very simple ( physically
) membrane
separators on the market now.
Using an hand powered high pressure
air pump in conjunction
with a small Permea separator
could provide a high level
nitrogen permeation into a biogas
generator in the first
stage before the methane is generated.
The resulting
sludge fertilizer would be high
in fixed N.
The Labor Required to separate
N2 from O2 of air is an essential
aspect of the practicability of
this system
Beginning with 1000 Kg of farm
waste
( Which is the equivalent of 1000
x 2.205 = 2205 pounds )
Presuming that 1/2 if this is carbohydrate = 500 Kg
Knowing that 1/10 of this weight
can be converted to fixed
Nitrogen = 500Kg/10 = 50 kg of
fixed N
Now dividing the weight in grams
by the gram molecular
weight of nitrogen , 50 kg / 28
= 1785. Gram moles of N2.
Now to discover the volume of N2
gas these moles occupy :
Each gram mole occupies 22 liters.
Thus 22 x 1785 = 39285.7
There are 39285.7 liters. Converting
to cubic feet in
order to begin pumping-energy
calculations: .0353 x 39285.7 =
1386.8 cubic feet.
Knowing that it requires 135 psig
to force the gas through
the separator, and looking for
the "pressure-volume work":
The pressure per square foot of
surface area is:
135 x 144 = 19440 lb.per ft^2.
Then multiplying the pressure per
square foot by the volume
in cubic feet: 19440 x 1386.8
= 26,959,392 foot-pounds.
Now converting foot pounds to watt
hours for the purpose of
calculating the hours of human
work to be expended:
First, foot pounds to watt hours : 26959392
x 3.766 x 10^-4 =
10153 watt hours.
To find the number of hours
of labor to achieve this work
oad, divide by the number of watt
hours a man can produce
by working for one hour i.e. by 100.
( When a man is working, he can
produce 1/7 hp which is about
100 watts.)
Thus :
10153/100 = 101.53 hours of labor for
50 Kg of fixed nitrogen
i.e. ruffly 100 lbs.
A hundred pounds of nitrogen would
nourish about 1/2 acre
and require two 50 hour weeks or two
hours a day for 50 days.
But there are some separators that operate
at 80 psig at a
small deficit in nitrogen quality and
this would reduce the
work load to 80/135 or .6 or to about
60 hrs per 100 lbs of
nitrogen.
I have no experience
of extreme hunger and so don't know
whether or not the effort would be worth
while. But it seems
that a typical 2 acre subsistence farm
or garden could produce
a significant amount of food with adequate
nitrogen if each
family member spent an hour a day for
four weeks working the
compressor.