Indiana Administrative Code › Title 327 - WATER POLLUTION CONTROL DIVISION › Article 5 - INDUSTRIAL WASTEWATER PRETREATMENT PROGRAMS AND NPDES › Rule 18 - Applicable Pretreatment Standards and Other Pretreatment Requirements › Section 18-7 - Combined wastestreams

Current through July 10, 2024
Authority: IC 13-14-8; IC 13-15-1-2; IC 13-15-2-1; IC
				  13-18-2; IC 13-18-3
Affected: IC 13-11-2; IC 13-13-5-1; IC 13-18-4
Sec. 7.
The combined wastestream formula is derived as
				  follows:
(1) Where process effluent is
				mixed prior to treatment with wastewaters other than those generated by the
				regulated process, alternative discharge limits may be derived by the control
				authority or by the industrial user with the written concurrence of the control
				authority and applied to the mixed effluent. When deriving alternative
				categorical limits, the control authority or industrial user shall calculate
				both an alternative daily maximum value using the daily maximum value specified
				in the appropriate categorical pretreatment standard and an alternative
				consecutive sampling day average value using the long term average value
				specified in the appropriate categorical pretreatment standard. The industrial
				user shall comply with the alternative daily maximum and long term average
				limits fixed by the control authority until the control authority modifies the
				limits or approves an industrial 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.
				An industrial user must immediately report any such material or significant
				change to the control authority. Where appropriate, new alternative categorical
				limits shall be calculated within thirty (30) days.
(2) As used in this section, "average daily
				flow" means a reasonable measure of the average daily flow for a thirty (30)
				day period. For new sources, flows shall be estimated using projected values.
				The alternative discharge limit for a specific pollutant shall be calculated by
				either of the following formulas:
(A)
				Alternative concentration limits:
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Where: CT = The alternative
				  concentration limit for the combined wastestreams.
Ci = The categorical pretreatment
				  standard concentration limit for a pollutant in the regulated stream i.
Fi = The average daily flow (at least
				  a thirty (30) day average) of stream i to the extent that it is regulated for
				  such pollutant.
FD = The average daily flow (at least
				  a thirty (30) day average) from any of the following:
(i) Boiler blowdown streams, noncontact
				cooling streams, storm water streams, and demineralizer backwash streams;
				provided, however, that where such streams contain a significant amount of a
				pollutant, and the combination of such streams, prior to treatment, with an
				industrial user's regulated process wastestream will result in a substantial
				reduction of that pollutant, the control authority, upon application of the
				industrial user, may exercise its discretion to determine whether such stream
				should be classified as diluted or unregulated. In its application to the
				control authority, the industrial user must provide engineering, production,
				sampling and analysis, and such other information so that the control authority
				can make its determination.
(ii)
				Sanitary wastestreams where such streams are not regulated by a categorical
				pretreatment standard.
(iii) Any
				process wastestreams that were or could have been entirely exempted from
				categorical pretreatment standards pursuant to paragraph 8 of the NRDC v.
				Costle Consent Decree (12 ERC 1833) for one (1) or more of the following
				reasons:
(AA) The pollutants of concern are
				not detectable in the effluent from the industrial user.
(BB) The pollutants of concern are present
				only in trace amounts and are neither causing or likely to cause toxic
				effects.
(CC) The pollutants of
				concern are present in amounts too small to be effectively reduced by
				technologies known to the administrator.
(DD) The wastestream contains only pollutants
				that are compatible with the POTW.
FT = The average daily flow (at least
				  a thirty (30) day average) through the combined treatment facility (includes
				  Fi, FD, and unregulated
				  streams).
N = The total number of regulated streams.