In event any industrial waste, the volume of which exceeds four thousand cubic feet per month, is found, by the Sanitary Board, to have an average suspended solid concentration in excess of three hundred fifty parts per million, the producer of such waste shall be surcharged an amount equal to the product of the actual volume of wastes in hundred cubic feet per billing period, exclusive of storm runoff, discharged to the public sanitary sewerage system and the "suspended solids surcharge rate. " The "suspended solids surcharge rate" shall be determined by the following formula:
Rs = 0.00626 x B (S - 350); where Rs equals the suspended solids surcharge rate in cents per one hundred cubic feet of waste discharged. B equals the average annual fixed, operating and maintenance cost of the sludge digestion, vacuum filtration and sludge disposal operations per pound of suspended solids received at the treatment works; prior to completion of the first year of operation the value of "B" shall be assumed to be 0.03 dollars (3¢); S equals the average suspended solids concentration of the abnormal industrial waste, expressed in parts per million as determined in accordance with Section 933.10.
The figure 350 appearing in the above formula corresponds to the maximum suspended solids concentration permissible without surcharge. As before, the figure 0.00626 is the factor to convert parts per million to pounds per one hundred cubic feet. No surcharge for excessive suspended solids will be applied until the treatment works goes into actual operation. No discount will be permitted for sewage or industrial wastes having a suspended solids concentration less than three hundred fifty parts per million.
(1969 Code §22-38)