(A) FOG Surcharge. In addition to the other matters set forth herein, an additional billable surcharge cost of $0.50/# FOG/DAY, for any discharge in excess of 100 mg/l but below an enforcement ceiling of 180 mg/l on fats, oils and grease (FOG) per day. This surcharge shall apply to the multiplicative product of the facility flow in millions of gallons per day, times the concentration of FOG in excess of 100 mg/l times the conversion factor of 8.34 pounds per gallon times the above unit rate.
(B) Sulfate surcharge.
(1) The following surcharge shall be applicable to all users for sulfate contained in their discharge. Sulfate is a pollutant, which may be converted to sulfide by bacterial action. Once in sulfide form, bacteria commonly found within a sanitary sewage collection system, combined with moisture present in the sewer can result in the formation of sulfuric acid. The presence of sulfate in high concentrations have proven to be extremely corrosive to concrete gravity sewers, in particular. In addition, sulfate converted by bacteria into sulfide may combine with hydrogen to form hydrogen sulfide, which is corrosive, odorous, and presents a serious threat to human health, especially if breathed at high concentrations (death is quite possible). Finally, sulfate can inhibit the activated sludge and anaerobic digestion processes. Both activated sludge treatment and anaerobic sludge digestion are critical to the operation of the treatment plant.
Sulfate - (Sulfate - 400 mg/l) x 30 days at $0.01
Where:
Sulfate = User monthly average sulfate discharge concentration, in mg/l
400 = Surcharge value for sulfate, below the enforcement ceiling limit of 500 mg/l, as contained in the ordinance, based upon digester inhibition
30 = days in calendar month
$0.01 = surcharge rate for sulfate
(2) The sulfate discharge shall be based upon the monthly average discharge for each user. The monthly average value shall be determined based upon averaging the results of all samples collected and analyzed during each calendar month. The surcharge shall only be calculated when a user’s monthly average sulfate concentration is in excess of 400 mg/l but below an enforcement ceiling of 500 mg/l, or other value specific to an individual permit.
(C) Additional surcharge parameters for BOD5 and TSS. These can be found in § 51.56, or its most recent modified version.
(Ord. 1785, passed 12-9-2002; Am. Ord. 2158, passed 1-26-2009)