PERMFILE123599 - Laserfiche WebLink

Home Browse Search

COLORADO DEPARTM£M' OF PUBLIC HE,~ILTH .t ND £PIV/RONh/£rVT Water Qttafrry Control Diwnon Amerrdmznt :Va. ~-Rntmnale. Page 5. Permit No. CO 0000732 If upon review of the results of this ndduiaral rnaritoring, it is determined that a reasonnbfe potential to exceed the WQS exists, dre permit wr[f be reopened to add effluent [imitations and arrv other appropriate condinons, subject ro public nonce provistats. d) lVlrole Ejflrtenr Toriaty (bVET I Testing: For orttja[l 0/~, chronic 6VET testing is required (See Part J A.S. of the permit.) 1) Ptvpose of IVET Tesri~tp: TJte Water Qunliry Caurol Drvtsion Aas established t/re use of WET tesrirtg as a method for identifying and controlling mxic discharges from uazstewnter treatment fncilides. 1VET testing is being utilized as a menus to ensure that there ore rto discharges of polltuants "in nmounrs. conceatratiau or combinations which are hmmfitl to the beneficial uses or toxic to humans. nninza(s. pfnnts, or aquatic life" as required by Section 31 JJ of the Basic Stnndnrds mtd Merhodoloeies for Srufaee Waters. 2) Jnstream Waste Concentration (IWCI: Where monitoring or limimtions for WET are deemed appropriate by the Division, chronic tnstrenm dilution ns represented by the chronic IWCls critical in deterntiniag tivhether acute or c/rronic conditions shall apply. For those discharges where the chronic /WC is greater than (>) 9. l %, chronic conditions apply, Hdtere the !WC is less than or equal to (s) 9 I acute conditions apply. Tire chronic /6VC is determined using the following equation !WC = [Facility Flow (FF)/(Srreant Chronic Low Flow (annual) + FF)J X J00% The flows and corresponding !WC for the appropriate discharge point are: Outfall Chronic Low Flow, (cjs) Facility Design Flow, (cfs) IWC, (%) • Ol5 0 0• l00% * This flow has not been determined at this time. however it is nonessential to this calculation because the low flow is Zero. The IWC for this permit is 100%, which represents a wastewater concentration of 100% effluent to 0% receiving stream. Thus, chronic WET testing is applicable for this outfalf. 3) Chronic WET Monitarine: Mine drainage from coal mines in Colorado has shown toxicity to aquatic life in ,come cases. On this basis, the potential for toziciN erists jar this new outfall. The permirtee will be required to conduct routine monitoring for chronic toxicity using fathead minnows. The permirtee conducted an Aquatic Impairment Slttdy in J995 for otttfall 011 to determine whether the cause of toriciry to Ceriodaphnia sp., which tivas determined to be total dissolved solids (TDS), was impacting the receiving water. The Division and EPA reviewed this study and determined that there was no discernible impact. /t was further determined that future testing using Ceriodaphnia sp. would be of little value. Tiros, WET testing of Ceriodaphnia sp. was waived far otttfall 011. The pennittee indicates that rite water quality of outjall OJS is sinttlar to that of outfall 01! and drat toriciry would be er/ttbited only by TDS. The Division ltas reviewed the nvnilable quality data acrd agrees with the pennittee. On this basis. the waiver of Ceriodapirnin sp. resting is extended to outfalf 015. Jf the si.r-time analysis required tinder this permit amendment indicates that tonic revels of metals are present or if roruine monitoring s/rows that the quality of otttfall 01_s is signiftcant[y different front outfall 01 J, the permit stay be reopened to add WET testing jot Ceriodaphnia sp. The results of the testing are to be reported on Division approved forms. The permirtee will be regtttred . ro conduct tvo types of statistical derivations on the data, ate looking jot any statistically significant difference in toxicity between the control and rite effluent concentrations mid the second idetrtifying the lC,,, should one exist. Both sets of cnlctdanons will look at the ftdl range of toxicity (lethality, growth and reproduction).