Fluidized Bed and Dissolved Oxygen Measurements
Procedure
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h1. Initial Experiments h2. Procedure {float:right|border=2px solid black}[!SandFilterSetup1.png|width=500px!|Initial Sand Filter Setup] h5. Initial sand filter experimental setup {float} |
These
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are
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the
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results
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of
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the
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first
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several
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experiments
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run,
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with
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the
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.
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This
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setup
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consisted
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of
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the
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flow
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accumulator
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and
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vertical
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glass
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filter
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column.
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A
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dissolved
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oxygen
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(DO)
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probe
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in
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the
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flow
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accumulator
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recorded
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the
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dissolved
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oxygen
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concentration
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of
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the
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inflowing
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tap
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water.
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The
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flow
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rate
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and
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temperature
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of
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the
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water
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was
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monitored
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by
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a
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pressure
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sensor
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and
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temperature
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probe
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inside
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the
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flow
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accumulator
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and
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controlled
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by
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valves
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on
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the
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hot
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and
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cold
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water
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lines.
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These
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valves
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were
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opened
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and
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shut
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by
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the program ProCoDA Software. Once the water had run through the filter column, it was collected in a small beaker containing another DO probe, which recorded the dissolved oxygen concentration of the outflowing water.
Results
The first experimental run used glass beads as the filter media and a flow rate of 200 mL/min. The unsuspended filter depth was 32 cm, and the temperature was held at a constant 20 degrees Celsius. #Figure 1 illustrates the change in dissolved oxygen that occurred over time, measured by DO probes. The yellow line represents the DO concentration of the inflowing tap water, and the blue line represents the DO of the outflowing water.
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program [Process Controller]. Once the water had run through the filter column, it was collected in a small beaker containing another DO probe, which recorded the dissolved oxygen concentration of the outflowing water. h2. Results The first experimental run used glass beads as the filter media and a flow rate of 200 mL/min. The unsuspended filter depth was 32 cm, and the temperature was held at a constant 20 degrees Celsius. [#Figure 1] illustrates the change in dissolved oxygen that occurred over time, measured by DO probes. The yellow line represents the DO concentration of the inflowing tap water, and the blue line represents the DO of the outflowing water. {anchor:Figure 1} {float:right|border=2px solid black}!DO vs. Time, 200mLmin.png|width=500px! h5. Figure 1: Initial results obtained using glass beads at\\a flow rate of 200 mL/min and a filter depth of 32 cm. {float} |
While
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the
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inflow
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DO
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concentration
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was
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about
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9mg/L,
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the
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outflow
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was
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roughly
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11
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mg/L.
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Overall,
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shows
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that
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the
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outflow
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DO
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concentration
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was
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measured
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as
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higher
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than
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the
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inflow
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concentration.
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This
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was
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inconsistent
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with
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what
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we
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predicted.
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Though
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it
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was
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possible
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that
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this
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setup
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would
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have
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no
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effect
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on
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the
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the
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DO
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of
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the
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water,
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the
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DO
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should
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not
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be
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able
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to
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increase
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inside
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the
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system.
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We
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found
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that
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this
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was
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most
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likely
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due
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to
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the
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error
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in
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the
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DO
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probes,
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which
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we
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found
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were
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not
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functioning
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properly.
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To
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download
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the
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data
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file
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for
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,
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click
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Conclusion
We concluded that we needed to purchase a new, more reliable DO probe to measure the oxygen concentration, or else we needed to find another method to measure the DO concentration. We decided to try out the sugar test in future experiments, which involves adding sugar to the outflowing water to see if bubbles form (if yes, then the water is still supersaturated). We also modified our setup to include a bubble collector in order to directly observe the amount of gas leaving the water. Together, the sugar tests and the new setup comprised the second phase of our experiments, which is completely described here.