Prior to any of the following calculations, the maximum allowable influent concentration to the Wastewater Treatment Plant (WWTP) and the background loading from nonindustrial sources shall be determined.
The following equations shall be used in determining the allowable loading to the Wastewater Treatment Plant and the background loading.
The Wastewater Treatment Plant loading is calculated as follows:
WWTP loading = (WWTP flow, mgd)(8.34)(Max. allowable influent conc., mg/1)
The background loading is calculated as follows:
Background Loading = (Background Flow, mgd)(8.34)(Background concentration, mg/1) The allowable loading allocated to the industries shall be calculated as follows:
Allowable Industry Loading = WWTP Loading - Background Loading
From this, the allowable industry concentration shall be calculated as follows:
Allowable Industry Concentration =
Allowable Industry Loading*
(8.34)(Industrial Flow, mgd)
*Minus the desired future growth allocation as determined by Council.
The industrial flow shall include only those industries which discharge a particular pollutant in a concentration exceeding the background concentration for that pollutant.
After sufficient data is generated as a result of the pretreatment program, the proportionate allocation method may be used to distribute the allowable loading to each discharger. This method allocates a loading to each discharger that is based on its current proportion of the total pollutant discharged to the Wastewater Treatment Plant. As a result, if any reduction is required, all dischargers shall reduce their loadings by an equal percentage. If concentration data is available for each pollutant from each discharger, the allocation can be allocated as follows:
L = LD x L1
Lt
Where L = pounds of pollutant to be allocated to a specific discharger,
LD = pounds of pollutant allowed to be discharged by all dischargers,
L1 = pounds of pollutant discharged by discharger in question (but not greater than the loading that is permitted based on the present local limit),
Lt = pounds of pollutant discharged by all dischargers for a specific pollutant.
(Ord. 4-2012. Passed 2-6-12.)