The basis of the surcharge shall be determined on either or both of 2 constituents of the water or wastes:
(A) Total suspended solids, and
(B) B.O.D., 5 days at 20°C. and as herein provided.
(C) When either or both the total suspended solids and B.O.D. of a water or waste accepted for admission to the city sewage works exceeds the value of these constituents for "normal sewage," the excess concentration in either or both, as the case may be, shall be evaluated volumetrically in terms of "normal sewage" and be subject to surcharge on the volume derived in accordance with the following formula:
Sv = (Sw-2500) X 0.65 X F X 133,690
2,500
plus (Bw-2000) X 0.65 X F X 133,690
2,000
which reduced to its simplest form is
Sv = F ( (Sw-2500) 35 plus (Bw-2000) 43).
(1) Sv is the derived volume of wastes in cubic feet subject to surcharge.
(2) Sw is the pounds per million gallons of suspended solids in the wastes as discharged.
(3) 2,500 is the pounds per million gallons of suspended solids in the "normal sewage."
(4) Bw is the pounds per million gallons of B.O.D. in the wastes as discharged.
(5) 2,000 is the pounds per million gallons of B.O.D. in "normal sewage."
(6) 0.65 is factor allowance for 65% degree of purification. (Present B.O.D. requirement for Cincinnati Pool established by Ohio River Valley Water Sanitation Commission.)
(7) F is the flow expressed in million gallons of the wastes as discharged.
(8) 133,690 is factor to convert million gallons to cubic feet.
(9) The equivalent volume of "normal sewage" as derived from the excess above the normal strength of any water and wastes shall be subject to a surcharge for the volume of equivalent "normal sewage" as computed from the formula, at a flat rate of $.03 for each 100 cubic feet, as above computed.
('73 Code, § 51.09)