HYDRO31322

• Permit No: C1980001
• IBM Index Class Name: Hydrology
• Doc Date: 6/6/2007
• Doc Name: Authorization to Discharge Under the Colo Discharge Permit System
• From: Department of Health Department
• To: DRMS
• Permit Index Doc Type: NPDES
• Media Type: D
• Archive: No

lam'
Perrnit No. CO-0032638
Page 21
15. Section 307 Toxics
If a toxic effluent standard or prohibition, including any applicable schedule of compliance specified, is established by
regulation pursuant to Section 307 of the Federal Act for a toxic pollutant which is present in the permittee's discharge and
such standard or prohibition is more stringent than any limitation upon such pollutant in the discharge permit, the Division
shall institute proceedings to modify or revoke and reissue the pemilt to conform to the toxic effluent standard or prohibition.
l6. Antibackslidine
a. A permit may not be renewed, reissued, or modified to contain effluent limitations adopted pursuant to Section 25-8-
503(1)(b) (BPJ) of the Water Quality Control Act, which are less stringent than the comparable effluent limitations or
standards in the previous permit, unless any one of the following exceptions is met and the conditions of paragraph (c) of
this section are met:
i) Material and substantial alterations or additions to the permitted facility occurred after permit issuance which justify
the application of less stringent effluent limitations; or
ii) Information is available which was not available at the time of permit issuance (other than revised regulations,
guidance, or test methods) and which would have justified the application of a less stringent effluent limitation or
standard at the time of pemrit issuance; or
iii) The Division detem'unes that technical mistakes or mistaken interpretations of law were made in issuing [he permit,
which justified relaxation of the effluent ]imitations or standards; or
iv) A less stringent efluent limitation or standard is necessary because of events over which the permittee has no control
and for which there is not reasonable available remedy; or
v) The permittee has received a permit variance; or
vi) The permittee has installed the treatment facilities requited to meet [he effluent limitations in the previous permit and
has properly operated and maintained the facilities but has nevertheless been unable to achieve the previous effluent
limitations, in which case, the limitations in the renewed, reissued, or modified permit may reflect the level of
pollutant control actually achieved (but shall not be less stringent than required by effluent guidelines in effect at the
time of permit renewal, reissuance, or modification).
b. A permit may not be renewed, reissued, or modified to contain effluent limitations adopted pursuant to b1.8(2(b) or (c) of
[he Colorado Discharge Permit System Regulations [hat are less stringent than the comparable effluent limitations in the
previous pemrit, unless any of the exceptions provided herein is met and the conditions of paragraph c. of [his section are
met.
i) In waters where the applicable water quality standard has not yet been attained, effluent limitations based on a total
maximum daily load or other waste load allocation maybe revised to be less stringent if the cumulative effect of all
such revisions assures attaitunen[ of such water quality standard, or the designated use which is not being attained is
removed in accordance with Section 31.6 of the Basic Standards.
ii) In waters where the applicable water quality standard has been attained, effluent limitations based on a total
maximum dairy load, other waste load allocation, or any other pernritting standard (including any water quality
standard) maybe revised to be less stringent if such revision is subject to and consistent with the antidegradation
provisions of Section 3 ].8 of the Basic Standards. Consistency with Section 31.8 shall be presumed if the waters in
question have been designated by the Commission as "use protected"; or
iii) Whether or not the applicable water quality standard has been attained:
(A) Material and substantial alterations or additions to the pemvtted facility occurred after pemut issuance which
justified the application of less stringent effluent limitations; or
(B) A less stringent effluent limitation is necessary because of events over which the pemrittee has no control and
for which there is not reasonable available remedy; or
(C) The permittee has received a permit variance; or
(D) The permittee has installed the treatment facilities required to meet the effluent limitations in the previous pemit
and has properly operated and maintained the facilities but has nevertheless been unable to achieve the previous