(A) Where a categorical user's regulated wastewaters mix with other regulated or unregulated wastewaters of the categorical user prior to the designated sampling manhole (for example, sample point), alternative pollutant limits may be derived by the Public Works Director using the following combined wastewater formula:
Where:
N | ||
 Ci Fi | FT - FD | |
CT= | i=1 | |
N | ||
| Fi | FT | |
i=1 |
CT = The alternative concentration limit for the combined wastestream
Ci = The categorical pretreatment standard limit for a pollutant in the regulated stream i
Fi = The average daily flow (at least a 30-day average) of stream i to the extent that it is regulated for such pollutant
FD = The average daily flow (at least a 30-day average) from boiler blow down streams, non-contact cooling streams, sanitary wastestreams, and demineralizer back wash, streams where such streams are not regulated by a categorical pretreatment standard
FT = The average daily flow (at least a 30-day average) through the combined treatment facility (includes Fi and FD)
N = The total number of regulated streams
(B) The categorical user shall comply with the alternative pollutant limit fixed by the Public Works Director until the Public Works Director modifies the limits or approves a user modification request. Modification is authorized whenever there is a material or significant change in the values used in the calculation to fix alternative limits for the regulated pollutant.
(C) An alternative discharge limit may not be used if the alternative limit is below the analytical detection limit for any of the regulated pollutants. As a result, the combined wastewater formula cannot be used, and wastestreams must be segregated.
(Ord. 09-03, passed 2-10-2009)