Sec. 861.8. Oxygen demand

(a) Biochemical oxygen demand.

The biochemical oxygen demand (BOD) shall mean the oxygen utilized during the first five days of aerobic decomposition at 20°C consistent with the latest edition of Standard Methods for the Examination of Water and Wastewater, published jointly by the American Public Health Association, the American Water Works Association, and the Water Pollution Control Federation.

(b) Carbonaceous oxygen demand.

The carbonaceous oxygen demand of wastes forms the basis of allocating the capacity of the receiving waters to assimilate the oxygen demand generated by the waste discharges. The carbonaceous, or first stage, oxygen demand is defined as the oxygen utilized in the carbonaceous reaction, as distinguished from that utilized in the nitrogenous or second stage reaction. The carbonaceous oxygen demand is calculated by projecting the logarithmic rate of carbonaceous oxidation to completion.

(c) Nitrogenous oxygen demand.

The commission will consider the nitrogenous demand of wastes, which generates a further gross oxygen demand upon the receiving waters, in establishing treatment requirements where appropriate.