4.4. SR 03-20-2017 - Laserfiche WebLink

Home Browse Search

Permit Modified; October 16, 2014 Elk River WWTF Page 15 Permit Expires: kne 30, 2018 Permit H: MN0020788 Chapter 3. Whole Effluent Toxicity (WET) Testing - Acute 7. Whole Effluent Toxicity Requirement Definitions 7.4 "Acute toxic unit (TUa) is the reciprocal of the effluent dilution that causes the acute effect by the end of the acute exposure period. For example, a TUa equals (100% effluent)/(48 LC50IEC50 for daphnia magna and ceriodaphnia dubia or 96 hour LC50iL:C50 for fathead minnows in %). Chapter 4. Total Residual Oxidants Domestic 1. General Requirements 1.1 Total Residual Chlorine must be analyzed immediately. " This means within 15 minutes or less of sample collection. (40 CFR fart 136 and Standard Methods for the Examination of Water and Wastewater, Latest Edition) 1.2 A Method Detection Limit (MDL) must be established for this parameter. 3 The Reportable Limit must be established for this parameter. This should be based on the Method Detection Limit and laboratory, analyst, and equipment used in the analysis. The Reportable Limit cannot be greater than 0.1 mg/L. 1.4 The Method Detection Limit and Reportable Limit should be reassessed when the method, equipment, laboratory, or analyst changes. 1.5 Monitoring results below the Reportable Limit should be reported as "<" the Reportable Limit. For example, if the Reportable Limit is -0.01 mg/L and a parameter is not detected at a value of 0.01'mg/L or greater, the concentration shall be reported as "<0.0lmg11,.." The symbol "<" means "less than." L6 The equipment should be checked against a known standard at least monthly. 1.7 "Daily Maximum" for Total Residual Chlorine (TRC) concentration limits means: a. The value of a single sample in a 24-hour period if the concentration of TRC in that sample is 0.03 8 mg/L or less, or below the Reportable Limit (RL). b. if the concentration of TRC in the first sample is greater than 0.03 8 mg/L or greater than the RL, reporting the average of two to twelve samples analyzed in a 24-hour period is allowed. The second sample must be taken two hours after the first sample and subsequent samples are to be taken at one-hour intervals thereafter, not to exceed a total of twelve samples in a 24-hour period. Values below the Reportable Limit for TRC are assumed to be zero for averaging purposes only. Whenever daily TRC values are averaged, the 0.038 mg/L limit must be met and the average value must be reported, not < the RL. c. The average value of multiple daily TRC effluent sample analyses must meet the 0.038 mg/L limit to be in compliance. Chapter 5. Surface Discharge Stations 1.. Requirements for Specific Stations 1.1 SD 001: Submit a monthly DMR by 21 days after the end of each calendar month following permit issuance. 2. Sampling Location 2.1 Samples for Station SD001 shall be collected from the final outlet control structure. 2.2 Samples and measurements required by this permit shall be representative of the monitored activity.