15
BOD MEASUREMENTS
Biochemical oxygen demand (BOD) is an indicator for the concentration of biodegradable organic
matter present in a sample of water. It can be used to infer the general quality of the water and its
degree of pollution. BOD measures the rate of oxygen uptake by microorganisms in a sample of water
at a fixed temperature and over a given period of time. To ensure that all other conditions are equal, a
very small amount of microorganism seed is added to each sample being tested. This seed is typically
generated by diluting activated sludge with deionized water. The samples are kept at 20 °C in the
dark and tested for dissolved oxygen (DO) after five days. The loss of dissolved oxygen in the sample,
once corrections have been made for the degree of dilution, is called the BOD
5
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Before measuring BOD, remember to set the BOD configuration from the SETUP menu (see page 30).
Press RANGE to access the BOD measurement screen.
Press BOD Data to view the BOD initial data management screen.
Press Compute to evaluate the BOD for a specified sample (available only when the measurement
is stable and at least one initial BOD data record has been memorized).
BOD initial data management screen
BOD Data is pressed while in BOD measurement screen.
Press Add new to add a new BOD initial data record (the key is available only when the measurement
is stable). A 200 records memory space is available for BOD initial data.
Press View ID to view the saved BOD initial values (the key is available only when at least one initial
BOD data record has been memorized).
By pressing Add New the BOD Parameters screen will be displayed:
OPERATIONAL GUIDE
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