HYDRO27537

• Permit No: C1980001
• IBM Index Class Name: Hydrology
• Doc Name: AUTHORIZATION TO DISCHARGE UNDER COLORADO DISCHARGE PERMIT SYSTEM
• Permit Index Doc Type: NPDES
• Media Type: D
• Archive: No

PART I
Permit No. CO-0(132638
Page No. 9
A. DEFINITION OF EFFLUENT LIMITATIONS
4. Whole Effluent Toxicity Testing Requirements (Chronic) Outfalls 004 and 007 (March-May Onlyl (continued)
Any permittee that is required to conduct aPTI/TIE investigation shall do so in conformance with procedures
identified in [he following documents, or as subsequently updated: l) Toxicity Identification Evaluation:
Characterization of Chronically Toxic Effluents. Phase 1, EPA/600/6-91/OOSF May 92, 2) Methods for Aquatic
Toxicirv Identification Evaluations. Phase I Toxicity Characterization Procedures, EPA/600/6-91/003 Feb. 9l
and 3) Methods for Aquatic Toxicitv Identification Evaluations. Phase Ii Toxicitv Identification Procedures,
EPA/600/3-88/035 Feb. 1989.
A founh document in this series is Methods for Aquatic Toxicitv Identification Evaluations, Phase 111 Toxicitv
Confirmation Procedures, EPA/600/3-88/036 Feb. 1989. As indicated by the title, this procedure is intended to
confirm that the suspected toxicant is truly the toxicant. This investigation is optional.
Within 90 days of the determination of the toxicant or no later than 2l0 days after demonstration of toxicity,
whichever is sooner, a control program is to be developed and received by the Division. The program shall set
down a method and procedure for elimination of the toxicity to acceptable levels.
e. Request For Relief
The permittee may request relief from further investigation and testing where the toxicant has no[ been
determined and the Division has determined suitable treatment does not appear possible. In requesting such
relief, the petmittee shall submit material sufficient to establish the following:
i. It has complied with terms and conditions of the permit compliance schedule for the PTI/T1E investigation
and other appropriate conditions as may have been required by the Division;
ii. During the period of the toxicity incident it has been in compliance with all other permit conditions,
including, in the case of a POTW, pre-treatment requirements;
iii. During [he period of the toxicity incident i[ has properly maintained and operated all facilities and systems
of vea[ment and control; and
iv. Despite the circumstances described in paragraphs i. and iii. above, the source and/or cause of toxicity
could no[ be located or resolved.
If deemed appropriate by the Division, the permit or the compliance schedule may be modified to revise the
ongoing monitoring and toxicity investigation requirements to avoid an unproductive expenditure of the
permittee's resources, provided that the underlying obligation to eliminate any continuing exceedance of the
toxicity limit shall remain.
f. Suontaneous Disaooearance
If toxicity spontaneously disappears at any time after a test failure, the permittee shall notify the Division in
writing within I4 days of a demonstration of disappearance of the toxicity. The Division may require the
permittee [o develop and submit additional information which may include, but is not limited to, the results of
additional testing. if no pattern of toxicity is identified or recurring toxicity is no[ identified, the toxicity
incident response is considered closed and normal WET testing shall resume.
g. Toxicirv Reooener
This permit may be reopened and modified (following proper adminisvative procedures) to include new
compliance dates, additional or modified numerical permit limitations, a new or different compliance schedule, a
change in the whole effluent toxicity testing protocol, or any other conditions related to the control of toxicants
if one or more of the following events occur:
i. Toxicity has been demonstrated in [he effluent and the permit does no[ contain a toxicity limitation.
ii. The PTI/TIE results indicate that the toxicant(s) represent pollutant(s) that may be controlled with specific
numerical limits, and the Division agrees that the numerical controls are the most appropriate course of
action.
iii. The PTI/TIE reveals other unique conditions or characteristics which, in the opinion of the Division, justify
the incorporation of unanticipated special conditions in the permit.
iv. The Division may reopen this permit and impose chronic toxicity limits where chronic toxicity is identified.
See Part I.C. for Definitions.