Xylem OxiTop Control OC 100, Руководство по эксплуатации

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OxiTop
®
Control OC 100 Overview
ba31114e07 08/2014
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1 Overview
1.1
The system
OxiTop
®
Control
The classical application field for the OxiTop
®
measuring heads and controller
is the BODx determination (BODx = Biochemical Oxygen Demand for the time
x). The evaluation of biological degradability (e.g. test according to OECD
301F) is also part of this field.
With different sample vessels, the OxiTop
®
measuring heads and the OxiTop
®
Controller 110 can also be used for other applications such as:

Evaluation of respiration and toxicity in earth, sludge, waste and sediment
(e.g. extraction of contaminated earth according to recovery concepts)

Evaluation of the respiration rate of cell cultures

Microbiological growth and stress examinations

Measurement of anaerobic degradation processes (e.g. biogas determina-
tion with the measuring head OxiTop
®
-C/B)
Accessories: see WTW catalog and price list
1.2 The measurement principle
The respirometric measurement is a pressure measurement. If oxygen is
consumed in a closed vessel at a constant temperature, a negative pressure
develops. If a gas is released, an overpressure develops. The OxiTop
®
measuring head measures and stores this pressure for the whole duration of a
measurement once started.
The OxiTop
®
OC 100 controller collects the pressure values from the
measuring heads and processes them.
The formula shown below is the basis for all calculations for the BOD using the
values from the OxiTop
®
measuring head.
 
 
2
0
m
l
l t
m
2
O p
T
T
V
V V
T R
O M
BOD
 



 







M(O
2
) Molecular weight (32000 mg/mol)
R Gas constant (83.144 l

mbar/mol

K)
T
0
Reference temperature (273.15 K)
T
m
Measuring temperature
V
t
Bottle volume (nominal volume in ml)
V
l
Sample volume in ml
a Bunsen absorption coefficient (0.03103)

p(O
2
) Difference of the D. O. partial pressure (mbar)