2017-05-11_PERMIT FILE - C1981012 ‎(18)‎

• Permit No: C1981012
• IBM Index Class Name: Permit File
• Doc Date: 5/11/2017
• Section_Exhibit Name: Exhibit 22 NPDES Permit
• Media Type: D
• Archive: No

In TRIM
COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division
Fact Sheet- Page 14, Permit No. C00000906
Table VII -2 Limitations Applicable to Outfall 001
Effluent Parameter
Effluent Limitations Maximum Concentrations
30 -Day Average
Daily Maximum
2 -Year Average
pH (su)
6.5-9
-
As, TR (pg/1)
Beginning 01 /01 /2022
0.032
-
0.0048
As, PD (pg/1)
-
540
81
Cd, PD (pg/1)
0.86
3.5
0.13
Cr+3, TR (pg/1)
-
79
12
Cr+3, PD (pg/1)
152
-
22
Cr+6, Dis (pg/1)
17
25
2.7
Cu, PD (pg/1)
18
28
2.3
Fe, TR (pg/1)
1471
-
391
Pb, PD (pg/1)
5.5
144
0.91
Mn, PD (pg/t)
2894
5251
456
Mo, TR (pg/1)
254
-
38
Hg, Tot (pg/1)
0.016
-
0.0024
Ni, PD (pg/1)
108
970
16
Se, PD (pg/1)
7.2
29
1.2
Ag, PD (pg/1)
0.21
5.6
0.032
Zn, PD (pg/1)
256
353
38
B, Tot (mg/1)
6.3
-
0.96
Chloride (mg/1)
396
60
Sulfide as H2S (mg/1)
0.0032
0.00048
3. Narrative Water Quality Standards - Section 31.11(1)(a)(iv) of The Basic Standards and Methodologies for
Surface Waters (Regulation No. 31) includes the narrative standard that State surface waters shall be free
of substances that are harmful to the beneficial uses or toxic to humans, animals, plants, or aquatic life.
a. Agricultural Use Protection - The WQA contains the evaluation of pollutants limited by narrative
standards, and specifically sodium absorption ratio (SAR) and electrical conductivity (EC), as outlined
by the Division's Implementing Narrative Standards in Discharge Permits for the Protection of Irrigated
Crops policy. The mass balance equation shown in the WQA was used for electrical conductivity to
calculate the maximum allowable effluent concentration, Mz, that could be discharged without causing
the narrative standard to be violated. The WQA also shows how the limitation for SAR was determined.
Stormwater discharges were not contemplated during development of the Protection of Irrigated Crops
policy; therefore, EC and SAR monitoring is not applicable to stormwater-only discharges.
b. Whole Effluent Toxicity - The Water Quality Control Division has established the use of WET testing as a
method for identifying and controlling toxic discharges from wastewater treatment facilities. WET
testing is being utilized as a means to ensure that there are no discharges of pollutants "in amounts,
concentrations or combinations which are harmful to the beneficial uses or toxic to humans, animals,
plants, or aquatic life" as required by Section 31.11 (1) of the Basic Standards and Methodologies for
Surface Waters. The requirements for WET testing are being implemented in accordance with Division
policy, Implementation of the Narrative Standard for Toxicity in Discharge Permits Using Whole Effluent