HYDRO23029

• Permit No: C1981041
• IBM Index Class Name: Hydrology
• Doc Date: 5/9/1994
• Doc Name: RATIONALE FOR PUBLIC NOTICE PN CO-0027146
• Permit Index Doc Type: NPDES
• Media Type: D
• Archive: No

PART I
Page lh of 19
Permit No. CO-0027146
B. MONITORING REQUIREMENTS
4. Acute WET Testine - Outfalls 001. 002. 004 and O15 (continued)
If the PTI allows resolution of the WET incident, the TIE need not necessarily
be conducted. If, however, WET is not identified or resolved during the PTI, the
TIE must be conducted within the allowed 120 day time frame.
Any permittee that is required to conduct a PTI/TIE investigation shall do so in
conformance with procedures identified in the following documents, or as
subsequently updated: 1) Methods for Aquatic Toxicity Identification
Evaluations. Phase I Toxicity Characterization Procedures, EPA/600/6-91/003 Feb.
91 and 2) Methods for Aquatic Toxicity Identification Evaluations. Phase II
Toxicity Identification Procedures, EPA/600/3-88/035 Feb. 1989.
A third document in this series is Methods for Aquatic Toxicity Identification
Evaluations. Phase III Toxicity 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 210 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 not been determined and the Division has determined suitable
treatment does not appear possible. In requesting such relief, the permittee
shall submit material sufficient to establish the following:
(i) It has complied with terms and conditions of the permit compliance
schedule for the PTI/TIE 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,
pretreatment requirements;
(iii) During the period of the toxicity incident it has properly maintained and
operated all facilities and systems of treatment and control; and
(iv) Despite the circumstances described in paragraphs (i) and (iii) above, the
source and/or cause of toxicity could not 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.
Amendment No. 1 Issued Effective