The charges for excesses of the constituents listed in § 53.087 will be based upon the “mass emission rate” of those constituents and determined thus:
(A) Mass Emission Rate - MER () = MG x C x 8.34
where: MER is the mass emission rate in pounds of a particular constituent
MG is the millions of gallons of wastewater discharged; and
C is the concentration in mg/l of the particular constituency being charged for (as an example) BOD, COD and the like, and 8.34 is equal to the number of pounds/one gallon of water.
(B) The amount of the charge in dollars will be calculated thus:
Ao - R x MER () where:
Ao is equal to the amount of the charge in dollars; and
R is equal to the rate of charge per lb. of constituent and MER () is equal to the lbs. of a constituent.
An example of surcharge:
“X” Corporation is a producer of canned foods. They discharged 1,000,000 gallons of wastewater in the month of January. Analysis found that the wastewater had the following characteristics: BOD - 400 mg/l; TSS - 950 mg/l. There were no other limitations exceeded in this example. There were 100 employees at the cannery. The limits of BOD and TSS are 250 mg/l.
The MER of BOD is equal to:
MERBOD = (400-250) x 8.34 x 1 MG
= (150) x 8.34 x 1
= 1,251 lbs. of BOD or 1.121 thousand lbs. BOD
If the charge for BOD is R - $70/1,000 lbs. BOD, then the total charge for BOD is equal
to, as...
Ao - R x MER
Ao - $70 x 1.121
Ao - $78.47
For TSS, the charge would be computed thusly:
MERTSS - (950-250) x 8.34 x IMG = 700 x 8.34 x 1 = 5,838 lbs. TSS; or
5.838 thousand lbs. TSS
At a charge of $70/thousand lbs., the charge for TSS - 5.838 x $70 = $408.66
Total Surcharge for January = BOD Charge $78.47
TSS Charge $378.66
= The higher charge which = $378.66
(C) Where a single discharge is such that more than one constituent is excessive and subject to surcharge, the actual surcharge will be based on the most costly constituent rather than on the total of excessive constituents.
(Ord. passed 12-4-1989)