...
Experiment
...
2:
...
Replicate
...
of
...
the
...
Previous
...
Sand
...
30 Experiment
Procedure
For this experiment, the general procedure for this set of experiments was followed using the following parameters:
Sand Grain Size: Sand 30 (0.59 mm - 0.84 mm)
Sand Bed Depth: 60 cm
Sand Bed Expansion: 50%
Aerator Air Pressure: 100 kPa
Flow Rate, measured manually: 485 ml/min
Results and Discussion
Data from the experiment indicate that similar amounts of gas were removed during each data collection period. Overall, the results were consistent. After each period the content air removed floated within the range of 1.981 mL/L - 2.002 mL/L. This might suggest that the components of the system function reliably.
The method of analyzing data was similar to that in Experiment 1. Figure 1. depicts the initial and final water levels in the bubble collector during each data collection period ("runs").
| Anchor | ||||
|---|---|---|---|---|
|
| Wiki Markup |
|---|
Experiment h2. Procedure For this experiment, the [general procedure|Final Results from the Fluidized Bed Method] for this set of experiments was followed using the following parameters: Sand Grain Size: Sand 30 (0.59 mm - 0.84 mm) Sand Bed Depth: 60 cm Sand Bed Expansion: 50% Aerator Air Pressure: 100 kPa Flow Rate, measured manually: 485 ml/min h2. Results and Discussion Data from the experiment indicate that similar amounts of gas were removed during each data collection period. Overall, the results were consistent. After each period the content air removed floated within the range of 1.981 mL/L - 2.002 mL/L. This might suggest that the components of the system function reliably. The method of analyzing data was similar to that in [Experiment 1|Experiment 1 - Replicate of the Previous Sand 40 Experiment]. Figure 1. depicts the initial and final water levels in the bubble collector during each data collection period ("runs"). {anchor:Figure 1} {float:left|border=12px solid white}[!figure 1.04.png|width="486", height="302"!|Experiment 2 - Graphs] {float} |
Each
...
run
...
represents
...
a
...
specific
...
time
...
period
...
during
...
which
...
the
...
water
...
level
...
in
...
bubble
...
collector
...
gradually
...
sinks
...
down
...
from
...
its
...
maximum
...
to
...
the
...
set
...
minimum.
...
This
...
period
...
is
...
represented
...
on
...
the
...
graph
...
when
...
the
...
line
...
slants
...
downward.
...
Once
...
the
...
minimum
...
water
...
level
...
is
...
reached,
...
the
...
system
...
has
...
to
...
refill
...
with
...
water
...
in
...
order
...
to
...
continue
...
the
...
runs.
...
For
...
this
...
reason,
...
the
...
water
...
outflow
...
valve
...
is
...
closed
...
until
...
the
...
water
...
level
...
reaches
...
the
...
set
...
maximum
...
point.
...
This
...
period
...
is
...
represented
...
on
...
the
...
graph
...
by
...
the
...
vertical
...
lines.
...
(This
...
section
...
is
...
redundant,
...
you
...
have
...
already
...
told
...
us
...
how
...
to
...
analyze
...
the
...
data)
...
Figure
...
1.
...
also
...
shows
...
that
...
the
...
bubble
...
collector
...
did
...
not
...
complete
...
the
...
run
...
during
...
the
...
third
...
period.
...
The
...
measured
...
water
...
level
...
in
...
the
...
bubble
...
collector
...
governs
...
when
...
the
...
bubble
...
collector
...
should
...
start
...
a
...
new
...
cycle
...
by
...
filling
...
up
...
with
...
water.
...
It
...
is
...
possible
...
that
...
the
...
cause
...
was
...
occasional
...
noise
...
in
...
data.
...
Since
...
the
...
data
...
averaging
...
period
...
is
...
10
...
seconds,
...
there
...
might
...
have
...
been
...
spikes
...
in
...
data
...
collected
...
in
...
this
...
particular
...
averaging
...
period.
...
The
...
multiple
...
spikes
...
that
...
lasted
...
just
...
for
...
a
...
few
...
seconds
...
could
...
have
...
caused
...
the
...
average
...
to
...
be
...
lower
...
than
...
the
...
minimum
...
water
...
level
...
set
...
point.
...
Essentially,
...
this
...
would
...
fulfill
...
the
...
condition
...
for
...
the
...
process
...
to
...
change
...
to
...
a
...
refill
...
state.
...
More
...
detailed
...
information
...
on
...
the
...
bubble
...
collector
...
setup
...
can
...
be
...
found
...
...
.
...
(Possibly...if
...
this
...
is
...
the
...
case,
...
I
...
would
...
make
...
your
...
bubble
...
collector
...
set-up
...
more
...
robust
...
so
...
this
...
cannot
...
happen
...
in
...
the
...
future)
...
The
...
initial
...
data
...
collection
...
period
...
was
...
omitted
...
from
...
the
...
analysis
...
since
...
because
...
of
...
the
...
setup
...
conditions
...
the
...
air
...
might
...
have
...
been
...
trapped
...
inside
...
the
...
system.
...
For
...
the
...
subsequent
...
data
...
collection
...
periods,
...
we
...
calculated
...
the
...
content
...
of
...
gas
...
removed
...
per
...
liter
...
of
...
water
...
sent
...
through
...
the
...
sand
...
filter.
...
For
...
reference,
...
the
...
formulas
...
can
...
be
...
found
...
...
.
...
For
...
these
...
calculations
...
we
...
used
...
following
...
values:
...
- radius
...
- of
...
- the
...
- bubble
...
- collector
...
- column:
...
- 1.9
...
- cm
...
- average
...
- flow
...
- rate:
...
- 485
...
- mL/min
...
We
...
fitted
...
a
...
line
...
to
...
each
...
of
...
the
...
runs
...
to
...
see
...
the
...
rate
...
of
...
change
...
of
...
the
...
water
...
level
...
inside
...
the
...
bubble
...
collector.
...
The
...
value
...
of
...
the
...
linear
...
fit
...
is
...
very
...
close
...
to
...
1,
...
indicating
...
that
...
the
...
data
...
can
...
be
...
modeled
...
accurately
...
using
...
a
...
linear
...
relationship.
...
Figure
...
2.
...
and
...
Figure
...
3.
...
show
...
the
...
linear
...
fit
...
line
...
for
...
the
...
second
...
data
...
collection
...
period,
...
and
...
more
...
detailed
...
graphs
...
can
...
also
...
can
...
be
...
found
...
here.
| Anchor | ||||
|---|---|---|---|---|
|
| Wiki Markup |
|---|
{anchor:Figure 2} {float:left|border=12px solid white}[!figure 2.02.png|width="489", height="315"!|Experiment 2 - Graphs] {float} {anchor:Figure 3} |
| Anchor | ||||
|---|---|---|---|---|
|
| Wiki Markup |
|---|
{float:left|border=12px solid white}[!figure 3.02.png|width="470", height="315"!|Experiment 2 - Graphs]
{float}
|
The
...
calculations
...
for
...
the
...
amount
...
of
...
gas
...
removed
...
during
...
each
...
data
...
collection
...
periods
...
gave
...
us
...
the
...
results
...
summarized
...
in
...
Table
...
1.
...
and
...
Figure
...
4.:
| Anchor | ||||
|---|---|---|---|---|
|
| Wiki Markup |
|---|
{anchor:Figure 4}
{float:left|border=12px solid white}[!figure 4.04.png|width="464", height="304"!|Experiment 2 - Graphs]
{float} |
| Wiki Markup |
|---|
{float:left|border=2px solid white|width="200"} h5. Table 1: Gas Removal vs. Collection Periods. ||Run||Slope (cm/min)||R ^2^ value||Dissolved Gas Removed (mL/L)|| |2|0.0854|.9944|1.9970| |3|0.0856|.9482|2.0017| |4|0.0847|.9952|1.9806| {float} \\ \\ Data was recorded for Sand 30 with each of the parameters specified under Procedure. The results of the experiment can be downloaded [here|^Copy of Data analysis and Graphs1.xls] in the form of the Excel sheet. The amount of gas removed during each run was consistent. The uniform results might indicate reliable functioning of the components of the system. As opposed to [Experiment 1|Experiment 1 - Replicate of the Previous Sand 40 Experiment], no clogging was witnessed at this time. The amount of gas removed is lower than the result from the Experiment 1, which involved using Sand 40. This might suggest that the sand with larger grain sizes might be less effective at gas removal than the sand with smaller ones. Larger sand grains have relatively lower surface area to volume ratio and thus provide less surface area to which the bubbles can attach to in the sand column. Although the sand grain size is just one of the factors that affect the gas removal rate, the results indicate that perhaps using filter media with higher surface area to volume ratio might help facilitate the gas removal process under certain conditions. However, the amount of removed gas is still a bit lower than the result from the [Fluidized Bed Experiment|Fluidized Bed after Super Saturator] done last semester, when the measured content of gas removed was 3.23 mL/L. The fluidized bed experiment involved the same sand parameters: Sand 30, depth = 60cm, bed expansion = 50%, aerator air pressure = 100kPa, except for the flow rate, which was 345 mL/min. The cause of the difference in results might be the experimental setup, which has been modified since last semester. The modifications include replacing the aerator with a new one. Perhaps the current aerator is not producing water that is supersaturated enough. That might affect the environment in which bubbles are formed, and thus indicate why only 2.00 mL/L of gas is removed. For further observation, we measured the dissolved oxygen content at three various points in the system. Detailed information can be found [here|FF Dissolved Oxygen Measurements]. h2. Conclusions The results of this experiment are quite consistent. Although the results are different from last semester's, we intend to use these results because of their consistency. We will probably have to adjust the data averaging time or check the set points for the valves, since one of the valves opened and cut short the third data collection period. That the gas removal is lower than last semester's is unexpected and is something we will look into. The sand filter may not working efficiently. This may be because the parameters are not optimal in this experiment, but it is also possible that the sand filter is not working well enough. The efficiency of the aerator will also have to be considered. Perhaps smaller aeration stones will allow for greater efficiency of gas dissolution. The lower gas removal, the inefficiency of the aerator, and the possible ineffectiveness of the sand filter may all be |
Data was recorded for Sand 30 with each of the parameters specified under Procedure. The results of the experiment can be downloaded here in the form of the Excel sheet. The amount of gas removed during each run was consistent. The uniform results might indicate reliable functioning of the components of the system. As opposed to Experiment 1, no clogging was witnessed at this time.
The amount of gas removed is lower than the result from the Experiment 1, which involved using Sand 40. This might suggest that the sand with larger grain sizes might be less effective at gas removal than the sand with smaller ones. Larger sand grains have relatively lower surface area to volume ratio and thus provide less surface area to which the bubbles can attach to in the sand column. Although the sand grain size is just one of the factors that affect the gas removal rate, the results indicate that perhaps using filter media with higher surface area to volume ratio might help facilitate the gas removal process under certain conditions.
However, the amount of removed gas is still a bit lower than the result from the Fluidized Bed Experiment done last semester, when the measured content of gas removed was 3.23 mL/L. The fluidized bed experiment involved the same sand parameters: Sand 30, depth = 60cm, bed expansion = 50%, aerator air pressure = 100kPa, except for the flow rate, which was 345 mL/min. The cause of the difference in results might be the experimental setup, which has been modified since last semester. The modifications include replacing the aerator with a new one. Perhaps the current aerator is not producing water that is supersaturated enough. That might affect the environment in which bubbles are formed, and thus indicate why only 2.00 mL/L of gas is removed. For further observation, we measured the dissolved oxygen content at three various points in the system. Detailed information can be found here.
Conclusions
The results of this experiment are quite consistent. Although the results are different from last semester's, we intend to use these results because of their consistency. We will probably have to adjust the data averaging time or check the set points for the valves, since one of the valves opened and cut short the third data collection period.
That the gas removal is lower than last semester's is unexpected and is something we will look into. The sand filter may not working efficiently. This may be because the parameters are not optimal in this experiment, but it is also possible that the sand filter is not working well enough.
The efficiency of the aerator will also have to be considered. Perhaps smaller aeration stones will allow for greater efficiency of gas dissolution. The lower gas removal, the inefficiency of the aerator, and the possible ineffectiveness of the sand filter may all be related.