(A) Liability. Each industrial or nonindustrial user who discharges wastes into the sewerage system shall be subject to a surcharge, in addition to the regular sewer charges, based on both the biochemical oxygen demand ( or on the chemical oxygen demand where BOD cannot be determined) and the suspended solids content of the wastes, when it can be determined that these wastes have a concentration greater than the following.
(1) A biochemical oxygen demand of 250 milligrams per liter. Where BOB cannot be determined, then, in lieu of BOD, a chemical oxygen demand of 500 milligrams per liter.
(2) A suspended solids content of 250 milligrams per liter.
(3) A phosphate content of six milligrams per liter.
(B) Computation. The surcharge shall be determined as follows. The excess pounds of BOD and Cod and of suspended solids will each be computed by first multiplying the customer's billing sewage volume measured in units of 1,000 gallons for the current billing period by the factor 0.00834 and then by multiplying this product by the difference between the concentrations set out in Division (A) above. The surcharge for each constituent will then be determine by multiplying the excess pounds of each constituent by the appropriate rate of surcharge set out in division (C) below.
(C) Rates. The rate of surcharge for each of the aforementioned constituents shall be as follows.
(1) For biochemical oxygen demand (BOD): $.163 per pound.
(2) For chemical oxygen demand (COD) where BOD cannot be determined: $.163 per pound.
(3) For suspended solids: $.142.
(4) For phosphates: $.820 per pound.
(D) Revision of rates. Prior to May 1 of each year, the Clerk-Treasurer shall submit to the Common Council a comparison of the calculated unit costs for removing BOD and the suspended solids from the wastewater treatment plant influent during the previous calendar year with the unit charges currently in effect in order to determine whether the current rates of surcharge are adequate or should be changed by the Common Council.
(Ord. 22-1978, passed 2-13-78; Am. Ord. 4-1979, passed 2-13-79; Am. Ord. 15-1984, passed 3-13-84)