Dust and bacteria removal equipment for controlling particulates in swine buildings


Bundy, D.S.; Veenhuizen, M.A.

Latest Developments in Livestock Housing: Seminar of the 2nd Technical Section of the C.I.G.R., University of Illinois, Urbana-Champaign, Illinois USA, June 22-26, 1987: 137-145

1987


The potential of air ionization to control dust and bacteria in livestock buildings was investigated, using a special chamber within an animal chamber. Insulation panels with exposed aluminium foil were glued to the walls and ceiling. All side walls were wired to a high voltage DC positive polarity power supply. The ceiling was negatively charged or attached to the ground depending on the experiment. Two types of electron generation systems were used for ionizing the air. It was found from the experiments that negatively ionized air is effective in reducing the concentration of airborne organisms in an animal isolation room; the reduction depends on aerosol infective dose, number of particles generated per unit time, natural resistance of exposed animal, defence mechanism of exposed animal. The use of negative ionized air is effective in reducing the aerosol concentration, depending on quantity of aerosol generated per unit time and the potential of re-entrainment of aerosol removed from the atmosphere.

DUST
AND
BACTERIA
REMOVAL
EQUIPMENT
FOR
CONTROLLING
PARTICULATES
IN
SWINE
BUILDINGS
D.
S.
Bundy
M.
A.
Veenhuizen
*
Member
ASAE
Associate
Member
ASAE
Over
the
past
several
years.
ventilation
rates
in
swine
facilities
have
been
decreasing
to
conserve
energy.
This
has
often
resulted
in
dust
concentrations
that
exceed
24-hour
concentrations
set
by
the
National
Primary
Ambient
Air-Quality
Standards.
Not
only
is
dust
corrosive
under
high
humidity
conditions,
but
it
serves
as
a
carrier
of
viruses
and
bacteria.
At
the
present
time,
there
is
no
air-filter
system
on
the
commercial
market
that
cleans
the
atmosphere
within
a
cost
range
acceptable
to
producers.
The
purpose
of
this
study
is
to
show
the
potential
of
using
air
ionization
to
control
dust
and
bacteria
in
swine
buildings.
LITERATURE
REVIEW
Dust
particles
may
be the
result
of
the
reduction
of
larger
masses
or
simply
dispersed
materials
that
were
already
pulverized.
Generally,
particles
are
not
considered
dust
unless
they
are
smaller
than
about
100
microns
(ASHRAE
1981).
In
swine
housing,
particles
with
a
diameter
of
less
than
100
microns
can
be
present
in
high
concentrations.
These
particles
are
introduced
into
the
environment
by
worker
and
animal
activity
as
well
as
material
movement.
Studies
done
on
workers
at
swine
confinement
facilities
show
a
higher
degree
of
respiratory
problems
than
are
common
in
the
public
at
large.
Dr.
Kelly
Donham
of
the
Institute
of
Agricultural
Medicine
and
Environmental
Health
at
the
University
of
Iowa
claims
dust
particles
in
swine
facilities
have
several
characteristics
indicative
of
their
potential
health
hazard,
including:
1)particle
size
in
the
respirable
range.
2)high
protein
concentration,
3)high
bacterial
and
fungal
counts,
4)endotoxin
activity,
and
5)adsorbed
irritating
gases
(Donham
and
Leininger.
1984).
Dust
levels
have
been
measured
at
levels
exceeding
the
National
Primary
Ambient
Air
Quality
Standards
and
Threshold
Limit
Value
in
swine
confinement
buildings
(Donham
et
al.,
1977).
ASHRAE
(1981)
states
that
industrial
hygienists
are
primarily
concerned
with
particles
less
than
2
microns
in
diameter
as
this
range
of
sizes
is
most
likely
to
be
retained
in
the
lungs.
Particles
larger
than
8
to
10
microns
in
diameter
are
separated
and
retained
by
the
upper
respiratory
tract,
while
*
Professor.
Agricultural
Engineering;
Instructor,
Midwest
Plan
Service;
Iowa
State
University.
Ames,
Iowa.
137
intermediate
sizes
are
deposited
mainly
in
the
conducting
airways
of
the
lungs,
from
which
they
are
cleared
or
coughed
out.
Curtis
(1983).
in
his
review
of
the
animal
environment,
cites
Hatch
and
Gross
(1961)
on
the
deposition
of
dust
particles
in
the
respiratory
tract.
He
writes
that
most
of
the
particles
5
microns
or
larger
are
retained
by
an
animal's
respiratory
tract,
especially
the
upper
part.
Fewer
of
the
particles
less
than
3
microns
in
equivalent
diameter
are
retained
in
the
upper
tract,
and
most
of
these
are
deposited
in
the
lower
respiratory
tract,
that
is,
in
the
lungs
themselves.
The
lungs
retain
almost
all
of
the
1
to
2
micron
particles
that
reach
them.
Measurements
done
in
swine
houses
give
various
results
in
percent
respirable
and
total
dust
levels.
Bundy
and
Hazen
(1975)
found
that
95%
of
the
dust
in
swine
buildings
is
in
a
size
considered
damaging
to
human
lungs.
Meyer
and
Manbeck
(1986)
collected
samples
from
8
commercial
hog
farms
and
found
average
respirable
dust
percentages
for
farrowing,
nursery,
and
gestation-
breeding
rooms
to
be
63.0,
19.6,
and
46.8
respectively,
with
average
dust
levels ranging
from
0.77
to
2.74
mg/m
3
.
Air
samples
were
taken
from
11
commercial
swine
finishing
units
in
Kansas
by
Stroik
and
Heber
(1986).
The
percent
respirable
range
was
83.0
to
97.6%
with
an
average
of
93.3%,
while
the
median
diameter
range
of
the
total
dust
sample
was
1.87
to
2.83
microns
with
an
average
of
2.22
microns.
Average
dust
levels
were
in
the
range
of
3.5
to
14.8
mg/m
3
.
In
studies
done
by
Donham
et
al.
(1979)
on
thirteen
swine
confinement
units,
health
histories
of
workers
were
taken.
Over
60%
of
the
workers
experienced
some
type
of
adverse
reaction
after
working
in
the
building
for
various
lengths
of
time.
Thirty-five
veterinarians
were
also
interviewed
with
32
reporting
adverse
effects
associated
with
work
in
livestock
confinement
units.
Stroik
and
Heber
(1986)
found
similar
results
in
a
survey
done
on
worker
health
problems
in
11
commercial
swine
finishing
houses.
In
a
swine
confinement
facility
dust
is
made
up
of
animal
hair,
skin,
dry
excreta,
and
feed
(Curtis,
1983;
Honey
and
McQuitty,
1979;
Stroik
and
Heber.
1986;).
Researchers
believe
most
dust
originates
from
the
feed
(Curtis
et
al.,
1975;
Honey
and
McQuitty,
1979).
Bundy
and
Hazen
(1975)
found
that
dust
levels
were
affected
when
different
feeding
methods
were
used.
Pelletized
feed
resulted
in
a
significantly
lower
dust
level
than
ground
feed
when
both
were
floor
fed.
Although
Nilsson
(1984)
concluded
that
most
of
the
total
dust
in
a
fattening
house
does
not
originate
from
feed
but
from
the
animals
themselves,
his
measurements
showed
that
dust
levels
did
increase
substantially
during
feeding
at
times
to
more
than
100
mg/m
3
.
Stroik
and
Heber
(1986)
used
optical
microscopy
to
identify
starch,
bran,
and
skin
particles
in
dust
collected
from
commercial
swine
facilities.
Starch
comprised
11%
of
the
total
counted
particles.
Most
of
the
larger
particles
occurred
as
aggregates
of
starch
particles,
but
bran
and
skin
were
also
identified
in
the
larger
class
sizes.
Honey
and
McQuitty
(1979)
used
photomicrographs
of
settled
dust
particles
and
concluded
that
the
primary
origin
was
feed.
Soybean
oil
has
been
used
as
an
additive
in
feed
to
control
the
dust
levels
in
swine
housing
(Gore
et
al.
1986).
The
object
of
this
experiment
was
to
evaluate
the
effects
on
nursery
air
quality
and
performance
of
weanling
pigs,
independent
of
calorie
density
of
the
diet,
by
adding
5%
soybean
oil
to
starter
diets.
Settled
dust
levels
were
reduced
approximately
45%
and
BCFP
counts
27%.
Pigs
fed
diets
containing
soybean
oil
consumed
4.3%
less
feed
and
had
4.1%
lower
feed
per
gain
ratio,
while
average
daily
gain
was
similar.
Tallow
has
also
been
used
as
an
additive
to
control
dust
and
enhance
pig
performance
(Chiba
et
el.
1985).
Trials
were
run
on
growing
finishing
pigs
138
in
modified—open—front
buildings.
Pigs
fed
5.0%
tallow
gained
8.3%
faster,
consumed
5.3%
less,
and
were
12.6%
more
efficient
than
the
control.
Aerial
dust
levels
were
reduced
49%
with
5.0%
tallow
while
settled
dust
levels
were
reduced
41%.
The
settled
dust
was
analyzed
for
crude
protein
content
and
examined
microscopically
and
was
determined
to
be
mainly
feed
dust.
The
effect
of
feeding
methods
using
self
feeders
and
floor
feeding
on
dust
concentrations
was
studied;
ground
feed,
pelleted
feed,
and
wetted
ground
feed
were
used.
Results
showed
dust
concentration
to
be
dependent
on
feeding
method
(Bundy
and
Hazen,
1975).
Zhang
and
Bundy
(1987)
tested
the
influence
of
air
velocity
and
temperature
on
dust
levels.
Results
showed
no
significant
effect
from
temperature
variation;
however,
dust
concentration
was
dependent
on
air
velocity
and
pig
activity.
Soybean
oil
has
been
added
to
a
swine
base
mix
and
tested
using
a
drop
test
in
laboratory
chambers
(Gast
and
Bundy,
1986).
Tests
compared
mineral
oil.
soybean
lecithin,
and
soybean
oil
added
individually
at
0.5%.
1.0%,
and
2.0%,
as
well,
as
combinations
of
lecithin
with
mineral
oil
or
soybean
oil.
Results
show
all
additives
to
be
highly
effective
at
removing
small
particles
(less
than
10
microns)
with
particle
counts
being
reduced
99%.
mass
samples
collected
by
filter
were
reduced
75.8%
to
99.5%
depending
on
type
and
amount
of
additive.
Combination
of
soybean
oil
and
lecithin
proved
to
be
the
most
effective
additive
with
soybean
oil
giving
similar
results
at
the
2.0%
level.
OBJECTIVE
The
objective
of
this
experiment
was
to
determine
the
potential
of
air
ionization
to
control
dust
and
bacteria
in
livestock
buildings.
More
specifically,
the
objectives
were:
1.
To
measure
total
bacteria
decay
with
no
attempt
to
differentiate
between
physical
and
biological
decay
by
utilizing
ionized
air,
2.
to
measure
the
decay
of
aerosols
by
utilizing
ionized
air,
and
3.
to
compare
two
methods
of
ionization
for
controlling
aerosols.
DESCRIPTION
OF
EQUIPMENT
A
special
chamber
3.6
m
x
4.9
m
x
2.3
m
high
was
framed
within
an
animal
chamber
(Figure
1).
Insulation
board
panels,
1.9
cm
thick,
with
exposed
aluminum
foil
were
glued
to
the
walls
and
ceiling.
All
sidewalls
were
wired
to
a
high
voltage
DC
positive
polarity
power
supply.
The
ceiling
was
negatively
charged
or
attached
to
ground
depending
on
the
experiment.
The
aluminum
foil
was
trimmed
back
from
the
bottom
edge
to
prevent
arcing
between
panels.
Two
types
of
electron
generation
systems
were
used
in
the
chamber.
Six
negatively
charged
needle
points
suspended
approximately
15
cm
below
the
ceiling
were
used
for
ionizing
the
air
for
the
first
part
of
the
study.
With
the
first
system,
the
ceiling
was
negatively
charged
to
drive
the
electrons
toward
the
aerosol
and
to
attract
the
positive
ions.
Figure
2
shows
the
electron
generation
and
air
distribution
system
for
the
second
part
of
the
study.
The
charging
of
the
air
was
by
65
needle
points
located
in
a
45
cm
x
45
cm
x
81
cm
chamber.
Air
was
passed
across
the
needle
139
point::
by
a
fen
rated
at
11.8
m
3
/s.
The
distribution
duct
was
0.3
m
x
0.3
m
x
2.4
m
with
10-2.5
cm
diameter
holes
for
air
and
electron
distribution.
Both
the
charging
duct
and
the
distribution
duct
were
lined
with
an
electrical
conducting
material.
The
liner
was
negatively
charged
to
capture
the
positive
ions
before
recombination
of
the
electrons
and
positive
ions
could
occur.
POS
NEG
14EG
.1,
Fig.
1
Isometric
of
Dust-Bacteria
Control
Chamber
45
cm
x
45
cm
x
81
cm
Charging
Duct
-7
0.3
m
x
0.3
m
x
2.4
m
Distribution
Duct
F
Fan
1U-_'.5
cm
Exhaust
Holes
2
sets
of
35
Needle
Points
for
Electron
Generation
Fig.
2
Electron
Generation
and
Distribution
Duct
System
140
PROCEDURE
AND
RESULTS
A
De
Vilbiss
1140
nebulizer
was
located
on
the
floor
in
the
center
of
the
chamber.
The
mean
particle
diameter
produced
by
the
nebulizer
was
2.5
m.
Escherichia
coli
S-13
phage
was
used
as
a
test
organism
for
evaluating
the
effect
of
ionization
on
controlling
airborne
microorganisms.
An
Anderson
slit
sampler
was
used
for
measuring
the
microorganism
decay
rate.
The
Anderson
sampler
rotated
360
in
1
hr.
A
Royco
215
portable
particle
counter
was
used
to
measure
the
aerosol
decay
rate.
Studies
shown
in
Figures
3,
4,
5,
and
6
are
results
from
using
the
6
point
charging
system.
The
chamber
walls
were
set
at
+10,000
V,
the
ceiling
at
-15,000
V
and
the
point
discharge
at
-22,000
V.
The
test
organisms
were
dispersed
through
the
nebulizing
fluid
for
the
studies
shown
in
Figures
3,
4,
and
5.
Figure
3
shows
the
results
from
a
rotating
slit
sampler.
Initially,
the
nebulizer
generated
aerosols
for
3
minutes
to
provide
a
heavy
concentration
of
aerosol
including
the
test
organisms.
At
the
end
of
3
minute,
the
nebulizer
was
turned
off
and
the
ionization
system
was
engaged.
At
the
20
minute
and
40
minute
period,
the
nebulizer
was
turned
on
for
90
seconds.
The
time
lapse
culture
shows
that
within
the
first
20
minutes
most
of
the
test
organisms
were
removed
from
the
chamber
atmosphere.
Less
time
was
required
to
remove
the
tests
organisms
after
each
additional
nebulization.
It
was
also
observed
that
the
initial
organism
density
was
less
at
the
time
of
each
additional
nebulization.
This
was
the
result
of
an
increased
number
of
electrons
in
the
chamber
with
respect
to
startup
time.
Figure
4
shows
a
similar
study
with
only
two
nebulizations.
The
second
nebulization
occurred
approximately
35
minutes
after
the
first.
The
reduced
organism
density
after
the
second
nebulization
was
the
result
of
more
free
electrons
in
the
chamber.
A
lower
aerosol
density
allows
an
accelerated
electron
build-up
in
the
chamber
which
is
illustrated
by
Figures
3
and
4.
Figure
5
shows
the
test
organisms
taken
from
a
sample
located
in
a
grounded
small
wire
cage
located
1
m
off
the
floor
in
the
center
of
the
chamber.
The
initial
nebulization
time
was
the
same
as
previously
described.
The
second
nebulization
was
approximately
20
minutes
after
the
first
for
90
seconds.
This
study
showed
that
the
grounded
wire
cage
minimized
the
number
of
organisms
entering
the
cage.
The
ionization
was
started
prior
to
sampling.
Figure
6
shows
the
decay
rate
of
aerosols
generated
from
3
minutes
of
nebulization
using
the
grid
needle
point
system.
All
particles
greater
than
0.5
microns
were
counted.
Ninety
five
percent
of
the
particles
were
removed
in
20
minutes
with
ionizatior.
The
particle
decay
follows
a
logarithmic
decay.
The
graph
also
shows
essentially
no
decay
by
only
gravitational
settling.
Figure
7
shows
a
similar
decay
curve
as
shown
in
Figure
6.
The
slope
of
the
decay
curve
is
not
as
steep
which
indicates
that
the
electron
generation
and
distribution
duct
system
is
less
effective
with
the
given
configuration
and
voltage
settings.
Other
settings
might
possibly
give
better
results.
141
ONIZATION
STARTED
FIRST
NEBULIZATION
THREE
NEBULIZATION
PERIODS
IONIZATION
STARTED
AFTER
FIRST
NEP
;.•
,
y•
'
-
SECOND
NEBULIZATION
IONIZATIO.
STARTED
AFTER
FIRST
NEBULIZATION
Fig.
3
One
Hour
Time-Lapse
Culture
of
S-13
Phage
Collected
by
a
Slit
Sampler
With
a
Second
and
Third
Nebulization
for
90
Seconds
at
20
Minutes
and
40
Minutes,
Respectively
Fig.
4
One
Hour
Time-Lapse
Culture
of
the
S-13
Phage
Collected
by
a
Slit
Sampler
With
a
Second
Nebulization
for
90
Seconds
at
35
Minutes
142
SECOND
NEBULIZATION
FIRST
NEBUIIZAIION
CAGE
AIR
IONIZATION
CONTINUOUS
1
o
f
Ae
r
oso
ls
)
Fig.
5
One
Hour
Time
Lapse
Culture
of
the
S-13
Phage
Collected
by
a
Slit
Sampler
In
a
Grounded
Wire
Cage
5.0
Ionization
Started
8%<90
00
(,>600>
%%
8 §
0
0
0
00
<>
Without
ionization
4.0
0
80
0
0
Ionization
00P
-22,000
V
Point
Discharge
0
-15,000
V
Ceiling
0
00
+10,000
V
Sidewalls
0
0
(
60000
3.0
000
0
0
CI)
00
bopo
o
21:•
40:
I
t
te
2.0
00
0
O
0
0
O
o
o
10
:0
30
40
Time
(minnte,)
Fig.
6
Decay
of
Aerosols
Larger
than
0.5
Microns
in
a
Chamber
with
a
Point
Discharge
Grid
System
143
0
0
0
0
z
0
()Without
Ionization
C)Ionization
-
28,000
V
Point
Discharge
-
10,000
V
Sidewalls
Ceiling
Grounded
-
10,000
V
Liner
—Ionization
Started
00;
90
7
0
°
S
8
0
9
88$'8g
0
2
'
8
001
4
0
oft°
00?
000
00
098p
Go
oog
l
e0X0
o
O
3.0
0
0000
00
0
0
0
0
0
L,.0
2.(1
0
10
20
30
40
50
Time
(minutes)
Fig.
7
Decay
of
Aerosols
Larger
than
0.5
Microns
in
a
Chamber
with
an
Electron
Generation
and
Distribution
System.
SUMMARY
Even
though
water
droplets
(aerosols)
were
evaluated
for
decay
rates
in
this
study,
similar
decay
rates
have
been
found
for
solid
particles.
From
these
studies
it
is
evident
that
negatively
ionized
air
is
effective
in
reducing
the
concentration
of
airborne
organisms
in
an
animal
isolation
room.
The
significance
of
this
reduction
depends
on
other
factors,
such
as,
(1)
aerosol
infective
dose,
(2)
number
of
particles
generated
per
unit
time,
(3)
natural
resistance
of
the
exposed
animal,
and
(4)
the
defense
mechanisms
of
the
exposed
animal.
The
use
of
negative
ionized
air
is
also
effective
in
reducing
the
concentration
of
aerosols.
The
significance
of
this
reduction
depends
on
(1)
the
quantity
of
aerosol
generated
per
unit
time,
and
(2)
the
potential
of
the
reentrainment
of
aerosol
(more
specifically
solid
particles)
removed
from
the
atmosphere.
Both
systems
were
found
to
be
effective
for
controlling
aerosols.
Most
management
systems
can
more
easily
incorporate
the
electron
generation
and
distribution
system
in
a
new
or
existing
livestock
building.
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1.
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1981.
Handbook
of
Fundamentals.
American
Society
of
Heating,
Refrigerating,
and
Air
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Inc.,
Atlanta,
GA.
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Bundy,
D.
S.
and
T.
E.
Hazen.
1974.
Effect
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ASAE
Paper
No.
74-4524.
144
3.
Bundy,
D.
S.
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E.
Hazen.
1975.
Dust
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L.
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K.
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Oil
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D.
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Effect
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