User Instructions

BOD MEASUREMENT

15. BOD MEASUREMENT

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

Before measuring BOD, remember to set the BOD configuration from the Setup menu.

BOD Procedure

DAY 0 (CAL DO)

Go to Setup and configure BOD configuration parameter which sets up expected sample and seed

concentrations.

Determine if you wish to save all BOD data or automatically delete starting data. Go to Setup and

configure Autodelete BOD start data.

Press MODE to access the BOD measurement screen.

Press BOD Data. The following screen will open. Place the probe into the BOD sample and allow the

measurement to stabilize. The sample should be well mixed. Follow all standard operating procedures.

Press Add new. The following screen will open and all parameters have to be filled out.

BOD Parameters:

• Bottle ID: a number used to identify a specific bottle.

Range: 0000 to 9999.