Hach BioTector B3500s, User Manual

Page: 102 / 166

Page 102
8.2.4 COD/BOD/DW Program
DISPLAY NO ▪ DISPLAY function, which is programmed as “NO” b y default,
allows the user to program COD and BOD results, and DW
“Drinking Water” parameters (which are % REMOVAL and
PASS/FAIL RESULT). When DISPLAY is programmed as
“YES”, the system displays the relevant parameters on screen.
When activated, the system sends the relevant 4-20mA signals
for COD and BOD (in mgO/l), and for REMOVAL (in %), to the
relevant result output channels if programmed. See Section
8.2.8 4-20mA Program for details.
COD/BOD PROGRAM
STREAM 1 1.0 0.0
TOC FACTOR 1.0
STREAM 2 1.0 0.0
TOC FACTOR 1.0
STREAM 3 1.0 0.0
TOC FACTOR 1.0
…………………… ……… ……
STREAM 6 1.0 0.0
TOC FACTOR 1.0
▪
In Stream 1 1.0 0.0 setting , the first setting “1.0” acts as the
“OVERALL FACTOR” and the second setting acts as the
“OFFSET FACTOR” in the following equation:
COD (and/or BOD) = [Overall Factor * (TOC Factor * TOC)] +
Offset Factor
▪ In TC analysis mode, instead of the TOC FACTOR, the TC
FACTOR is displayed in this menu and used in above equation.
▪ If the DISPLAY is programmed as COD and/or BOD above, the
system multiplies the TOC result of the corresponding stream
(STREAM 1-3) with the TOC FACTOR and with the OVERALL
FACTOR and adds the OFFSET FACTOR to calculate the COD
and/or BOD value.
▪
The STREAM FACTOR for each stream is obtained following
the procedures described in information sheet “ I030. TOC to
COD or BOD Correlation Method ” , which is available in the
MMC/SD card shipped with the BioTector.
▪ Stream 1 factor is used for manual samples and calibration
standards.
DW PROGRAM
DETENTION TIME
32m
TOC < 2.0mgC/l 0%
TOC < 4.0mgC/l 35%
TOC < 8.0mgC/l 45%
TOC > 8.0mgC/l 50%
▪
When the display of the DW “Drinking Water” parameter is
activated with the DISPLAY function above, BioTector calculates
the % REMOVAL values using the measured TOC results on
STREAM 1 (SAMPLE 1) and STREAM 2 (SAMPLE 2), which
must be installed and connected to the INLET and OUTLET
streams respectively.
▪ DETENTION TIME is a site specific time interval, during which
the water flows through the water treatment plant or a treatment
system to achieve a certain level of organic removal (in %) from
the inlet stream (STREAM 1). This time must be programmed on
site depending on site specific process conditions and
requirements. BioTector uses this time to synchronize the inlet
and outlet TOC measurements for the calculation of %
REMOVAL.
▪
The % REMOVAL (organic removal) value is calculated as
follows:
REMOVAL (%) = { [ (STREAM 1 TOC Result)
– (STREAM 2
TOC RESULT) ] / (STREAM 1 TOC Result) } * 100
Note that STREAM 2 (OUTLET) TOC result in above equation,
is the STREAM 2 result, which is evaluated by the system after
the completion of the DETENTION TIME described above.
▪ When DW display is activated, the % REMOVAL values are
displayed on the Analysis Data Screen and also in the reaction
archive menus.
▪ TOC < (LESS THAN) XmgC/l and X% values define various
concentration levels at which a certain % REMOVAL must be
achieved for a PASS or a FAIL condition. When the TOC result
is measured for the INLET stream (STREAM 1), BioTector
evaluates the TOC result for the OUTLET stream (STREAM 2),
which is available at the end of the DETENTION TIME, and
based on the measured concentration levels, the % REMOVAL
value is calculated.