Laserfiche WebLink
COLORADO DEPARTMENT OF HEALTH, Water Quality Control Division <br />Rationale - Page 3. Permit No. CO-0033367 <br /> <br />PURPOSE OF AMENDMENT: (Cont.) <br />WWTF discharge. (Pond 004 has not discharged during the past five years.) <br />The permittee has therefore requested that discharge point 001 be eliminated <br />from the permit. Thin change is shown in Figure 1. In addition, some of the <br />parameters for 001 are now applied to 004. (The previous limits for 004 also <br />still apply.) <br />APPLICABLE RULES AND REGULATIONS: <br />Although the limits for 002 and 003 have not changed, and the limits for 005 <br />will be consistent with 002, the following discussion is included to clearly <br />demonstrate how these limits were derived. <br />A. Federal <br />At the federal level, Best Practicable Control Technology CBPT) and Best <br />Available Technology Economically Achievable (BAT) are applicable to this <br />facility. These regulations are taken from the Coal Mining Point Source <br />Category, 40CFR 434. The applicable sections within this regulation are <br />Parts 434.42, 434.43, and 434.45 for active mining areas, and Part 434.63 <br />for precipitation events. <br />B. State <br />State Effluent Standards (SES) (10.1.0) apply to all discharges in the <br />state for parameters not superseded by Federal Effluent Guidelines or <br />Stream Standards. The SES apply to the more conventional pollutants. In <br />addition to these standards, the State also moat apply the receiving <br />stream Water Quality Standards (WQS) which are appropriate for this <br />facility. <br />The WQS are applied based on a mass balance for each pollutant in <br />question. The variables used in the calculation are the allowable <br />in-stream level (WQS), the chronic stream low flow (Q3-30)~ the effluent <br />flow (Qeff)+ and the background concentration (Camb)+ as indicated in <br />Appendix C. The mass balance equation is also shown. <br />LIMITATIONS AND RATIONALE; <br />Table 1 presents a comparison of appropriate limitations for active mining. <br />Table 2 shows limitations selected as being the moat stringent of those in <br />Table 1, with the exception of Total Suspended Solids (TSS). In the case of <br />TSS, the federal limits are overriding. The limits for 004 are in Table 3. <br /> <br />