The OxyGuard Handy BOD permits the use of the usual procedure for the determination of the BOD value, but replaces chemical analysis of the oxygen content of the liquids with direct measurement. The use of an OxyGuard DO meter to measure the oxygen content has clear advantages over analysis. It is easier to avoid pollution of the sample, and full advantage can be made of the 0.1 mg/l resolution and accuracy of the DO meter, as well as its true zero - it measures correctly to 0.0 mg/l. The DO meter is specified in a separate brochure.
One practical method is to dilute the sample to 1 liter with aerated water based on an estimation of the actual BOD value. Funnels are loosely placed on 3 OxyGuard bottles and these are filled with the diluted sample so that there is about 1 cm liquid in each funnel. A stirrer magnet is placed in each bottle. If the samples are to be aerated further this should be done through the funnels. Do not place bottles with funnels in place in sunlight or near sources of radiant heat. The bottles are placed on a slow magnetic stirrer and the DO content measured by lowering the probe into the bottle through the funnel. The funnels are removed - the bottles fill completely with liquid from the funnels. The bottles are sealed with the stoppers and incubated. After incubation the DO levels are measured by lowering the probe directly into the bottles. The BOD values are calculated as usual.
DO measurement can be performed very quickly - the Oxyguard probe has a fast response. The O-ring on the probe body acts as a stop so that the probe rests with its tip centrally in the sample. Take care not to trap an air bubble at the membrane when the probe is lowered into the sample.
Where necessary the BOD values of liquids used are determined in a similar manner.
Ordering InformationH05KIT: 1 Handy Delta, 1 bottles with funnels and stoppers.The meters are delivered ready for immediate use.
H05XL: 1 bottles with stoppers and funnels.