YSI BOD Analyst Pro - Manual (Page 63)

YSI BOD Analyst Pro ® User Manual 63
The Bench Sheet related to Criteria is discussed in more in Section 10, Customizing Your
Program. A few explanations will be pointed out here to understand the Final Batch for this test.
There are no BODs calculated for Dilution Blank. The DO depletions have limits and the BOD
has no particular significance or need in other calculations.
The Standard was performed for this example with one seed prep named Seed and identified by
the number (6) in the Seed Corrections field. The Final BOD is the average of the two bottles
tested. Note that the average is 181 mg/l. Neither test is “marked” since the acceptable range for
this test is 163 to 237 mg/l (default values).
The sample named Seed has two of the three dilutions marked. The reason code that would
display in the Check Result field at the bottom would be D% Seed Depletion Percentage 50%.
That means under Criteria the program selects the bottle in the Seed sample that is closest to 50%
depletion of the Initial DO reading. Therefore, when all three are calculated by DO depl / Initial
DO for B#s 4, 5, and 6 the results would be 34.0%, 49.7%, and 51.4%, respectively. B#5 is
closest to 50% depletion. The other two are marked and the Final BOD of 128 mg/l is reported.
The Influent is used both as a seed for Effluent and as a sample of interest in the process. The
seed rule of 50% depletion applies just as described above and B#9 was closest to 50% at 52.1%
(4.37/8.38). The Final BOD is reported as B#9 since when a bottle is marked it can not be used in
the calculation. The Final BOD of 109.2 is reported. Note that the cursor was placed on B#9 to
show that the Test is Valid message appears in the Check Result field at the bottom of the Bench
Sheet.
The Effluent sample represented by three bottles (dilutions) were all “unmarked” and therefore
the BOD of each bottle was averaged for a Final BOD of 8.5 mg/l.
You should also take note that Incubation Date was 07/11/2010 to 07/16/2010 which is 5 days.
The current date is also 07/16/2010. There is a message in Note Field and the Technician
designation was AZ. The serial number field shows that serial numbers are applied giving unique
identity to each bottle in the entire database file. The fact that the serial numbers are letter and not
numbers is related to the high/low values assigned as limits and to the total bottles assigned to
date in the database.
Seed Corrections [(mg/l)/ml] or DO consumed for each ml of seed used are displayed in the
Seed Corr (mg.l) field. Take note that in the Seed Corrections column of the Bench Sheet that
these factors have been multiplied by the ml/bottle to give the results in this column. Seed
corrections are used to determine BOD values for each row that includes seed. The equation for
the calculation is shown in Section 5.13.
Finally if you chose to change one or more criteria in evaluating your test you would make the
change using Setup / Criteria and then click on Manual Check to update the criteria
calculations. An updated Bench Sheet would appear that may change some marked/unmarked
rows and possibly some BOD values.
For more information see other parts of the user manual including Customizing Your Program at
the end of the manual.