The method consists of filling with diluted and seeded sample,
to overflowing, an airtight bottle of specified size and incubating
it at the specified temperature for 5 d. Dissolved oxygen is
measured initially and after incubation, and the BOD is computed
from the difference between initial and final DO. Because
the initial DO is determined shortly after the dilution is made, all oxygen uptake occurring after this measurement is included in the BOD measurement.
For sampling and storage procedures, see ¶ 4a below