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Home My WebLink About#191 2011-final INSPECTION REPORT ROUTING SHEET To be attached to all inspection reports in-house only. Laboratory Cert. #: #191 Laboratory Name: Roxboro WWTP Laboratory Inspection Type: Municipal Maintenance Inspector Name(s): Jeffrey R. Adams Inspection Date: July 28, 2011 Date Report Completed: August 18, 2011 Date Forwarded to Reviewer: August 18, 2011 Reviewed by: Todd Crawford Date Review Completed: August 18, 2011 Cover Letter to use: Insp. Initial X Insp. Reg. Insp. No Finding Insp. CP ___ Corrected Unit Supervisor: Dana Satterwhite Date Received: August 19, 2011 Date Forwarded to Linda: August 24, 2011 Date Mailed: August 24, 2011 _____________________________________________________________________ On-Site Inspection Report LABORATORY NAME: Roxboro WWTP Laboratory NPDES PERMIT #: NC0021024 and NC0003042 ADDRESS: P.O. Box 128 Roxboro, NC 27573 CERTIFICATE #: 191 DATE OF INSPECTION: July 28, 2011 TYPE OF INSPECTION: Municipal Maintenance AUDITOR(S): Jeffrey R. Adams LOCAL PERSON(S) CONTACTED: Crystal Shotwell and Derek Clayton I. INTRODUCTION: This laboratory was inspected to verify its compliance with the requirements of 15A NCAC 2H .0800 for the analysis of environmental samples. II. GENERAL COMMENTS: The laboratory was clean and well organized. The facility has all the equipment necessary to perform the analyses. Records were well organized; however, some quality control procedures need to be implemented. As a reminder, the 2011 proficiency testing results must be submitted by your vendor and received in the certification office no later than October 31, 2011. The laboratory was given a packet containing North Carolina Laboratory Certification quality control requirements and policies during the inspection. Findings B and C are new policies that have been implemented since the last inspection. III. FINDINGS, REQUIREMENTS, COMMENTS AND RECOMMENDATIONS: General Laboratory A. Finding: The analytical balance weights have not been verified against ASTM standard weights. Requirement: ASTM Class 1 and 2 weights must be verified at least every 5 years. ASTM Class 1 weights (20 g to 25 kg) and ASTM Class 2 weights (10 g to 1 mg) are equivalent to the NBS Class S weights specified in 15A NCAC 2H .0805 (a) (7) (K). Ref: North Carolina Wastewater/Groundwater Laboratory Certification Policy. See attachment, titled Weight Verification, for additional guidance. Page 2 #191 Roxboro WWTP Laboratory B. Finding: Auto-pipettors are not calibrated twice per year. Requirement: Mechanical volumetric liquid-dispensing devices (e.g., fixed and adjustable auto- pipettors, bottle-top dispensers, etc.) must be calibrated at least twice per year, approximately six months apart and documented. Each liquid-dispensing device must meet the manufacturer’s statement of accuracy. Ref: North Carolina Wastewater/Groundwater Laboratory Certification Policy. (See attachment, titled Calibration of Mechanical Volumetric Liquid-Dispensing Devices Procedure, for an example procedure for calibrating auto-pipettors. NOTE: Other procedures may also be suitable or this may be accomplished by a commercial calibration company.) BOD – Standard Methods, 18th Edition, 5210 B D. Finding: BOD blank values were >0.20 mg/L on several data sets. Requirement: The DO uptake in 5 days must not be more than 0.20 mg/L and preferably not more than 0.10 mg/L, before making seed corrections. This means readings should be made to two decimal places. If the dilution water blank exceeds 0.20 mg/L, discard all data for tests using this dilution water or clearly identify such sample in data records. Ref: North Carolina Wastewater/Groundwater Laboratory Certification Policy based upon Standard Methods, 21st Edition, 5210 B. (6) (c). Recommendation: The BOD blank values have been consistently averaging >0.20 mg/L. It is recommended that the laboratory seek an outside water source and set up and analyze a comparison check of a series of water blanks, using the in-house water vs. the outside water. Comment: The laboratory has been qualifying the data on the DMR reports as required; however, steps must be taken to correct the problem. pH – Standard Methods, 18th Edition, 4500 H+ B pH – EPA SW–846 Method 9040 C E. Finding: The laboratory is analyzing and reporting sludge by SW -846 Method 9040 C, but is not certified for this method. Requirement: Municipal and Industrial Laboratories are required to obtain certification for parameters which will be reported to the State to comply with State surface water monitoring, groundwater, and pretreatment Rules. Ref: 15A NCAC 02H .0804 (a). Please submit an Amendment to Certification form requesting the addition of pH SW-846 Method 9040 C with the response to this inspection report. Comment: The laboratory is analyzing sludge samples with a solid content of 3% and a water content of 97%. pH – Standard Methods, 18th Edition, 4500 H+ B Total Residual Chlorine – Standard Methods, 18th Edition, 4500 Cl G Comment: The laboratory also analyses samples for the water treatment plant for Dissolved Oxygen, Settleable Solids, pH and Total Residual Chlorine (TRC). After review of the pH and Total Residual Chlorine data of the water treatment plant and observing the times being recorded on the benchsheets, there is a concern that the distance between the water plant and the wastewater laboratory may be too great to meet the 15 minute holding time for pH and TRC. The laboratory states the travel time Page 3 #191 Roxboro WWTP Laboratory between locations is approximately 8 to 10 minutes, therefore making it difficult to meet the 15 minute sample hold time. Recommendation: To ensure compliance with Clean Water Act requirements, it is recommended that the water treatment plant obtain a separate field laboratory certification. The requirements for initial certification of field laboratories are described on the Laboratory Certification website at http://portal.ncdenr.org/web/wq/lab/cert/field. To begin the process, simply complete the Field Parameter Environmental Laboratory Certification application and analyze the appropriate PT samples. The inspector will be glad to assist the water treatment plant personnel with obtaining certification. IV. PAPER TRAIL INVESTIGATION: The paper trail consisted of comparing laboratory benchsheets and contract lab reports to Discharge Monitoring Reports (DMRs) submitted to the North Carolina Division of Water Quality. Data were reviewed for the City of Roxboro WWTP (NPDES permit #NC0021024) and the City of Roxboro WTP (NPDES permit #NC0003042) for February, March and April, 2011. The following error was noted for permit #NC0021024: Date Parameter Location Value on Benchsheet Value on DMR 5/2/11 Total Residual Chlorine Effluent 37 µg/L < 15 µg/L In order to avoid questions of legality, it is recommended that you contact the appropriate Regional Office for guidance as to whether an amended Discharge Monitoring Report will be required. A copy of this report will be forwarded to the Regional Office. V. CONCLUSIONS: Correcting the above-cited findings and implementing the recommendations will help this lab to produce quality data and meet certification requirements. The inspector would like to thank the staff for its assistance during the inspection and data review process. Please respond to all findings. Report prepared by: Jeffrey R. Adams Date: August 18, 2011 Report reviewed by: Todd Crawford Date: August 18, 2011 Calibration of Mechanical Volumetric Liquid-Dispensing Devices Procedure A laboratory may use the following method for the gravimetric determination of measurement error of mechanical volumetric liquid-dispensing devices (e.g., fixed and adjustable auto-pipettors, bottle-top dispensers, etc.) used to dispense volumes greater than or equal to 100 μl. Apparatus and Equipment Weighing vessel (of sufficient capacity to hold all volumes dispensed for the test and a 3:1 height-to- diameter ratio is recommended to minimize evaporation) Reagent water (e.g., distilled or deionized water) Analytical balance (accurate to 0.0001 g for 100 μl to 10 ml, and accurate to 1 mg for 10 ml to 200 ml dispensed volumes) Calibrated thermometer (graduated, at a minimum, in 0.5 ºC increments) Documentation Requirements Date Analyst's signature or initials Device identification (if there is no unique identification such as serial number, assign a laboratory identification) Temperature of the reagent water Nominal or test volume Weights of dispensed volumes Procedure 1. Allow apparatus and reagent water to equilibrate to room temperature. 2. Check the calibration of the balance. 3. Wet the liquid-dispensing device and lubricate the piston insuring smooth operation by pipetting several volumes to waste. 4. Weigh the vessel and tare the balance. 5. Dispense a minimum of five aliquots of water into the vessel, weighing and recording the mass for each replicate. 6. Calculate the following: m = mean mass = total of individual weight measurements ÷ total number of measurements Z = Z correction factor obtained from Table 1 using the temperature of the test liquid and current barometric pressure. V = volume equivalent (or corrected volume) of mass measured = m x Z RE = relative error (%) = [Vm - Vo] x 100 Vo where: Vm = corrected mean volume = total of corrected volumes ÷ total number of dispensed volumes Vo = nominal or test volume S = standard deviation = For each replicate, subtract the mean volume from the corrected volume, then square the value. Sum the squared values of all replicates, and then divide the sum by n- 1 (the number of measurements minus 1). Take the square root of this value to get the standard deviation. CV = coefficient of variation (%) = s x 100 Vm To simplify this process, spreadsheets for calculating and documenting the relative error and coefficient of variation can be found on the NC Wastewater/Groundwater Laboratory Certification (NC WW/GW LC) website at http://h2o.enr.state.nc.us/lab/download.htm. The Relative Error (a measure of accuracy) and Coefficient of Variation (a measure of precision) must not be greater than the manufacturer's specifications. If the results are greater than the manufacturer's specification, repeat the procedure. If the results remain greater, follow the manufacturer's instructions for maintenance and adjustment and repeat the procedure. If repeated calibration attempts do not yield results within the manufacturer's specifications, the liquid-dispensing device must be repaired or replaced. Note: Microliter pipettors may need to be tested under more rigorously controlled conditions or sent to a calibration service for testing. Since most analytical balances used in environmental laboratories read to only four decimal places, it may be necessary, when checking microliter pipettors (less than 1000 μl), to include the weight of the weighing vessel in each replicate and subtract it and subsequent aliquots out manually in order to have a measurable mass for the purpose of this verification. Contact your auditor if you have questions. Table 1. Z Correction Factor Table. Temperat ure C Air pressure, kPa (mbar) 80 (800) 85 (850) 90 (900) 95 (950) 100 (1000) 101.3 (1013) 105 (1050) 15.0 1.0017 1.0018 1.0019 1.0019 1.0020 1.0020 1.0020 15.5 1.0018 1.0019 1.0019 1.0020 1.0020 1.0020 1.0021 16.0 1.0019 1.0020 1.0020 1.0021 1.0021 1.0021 1.0022 16.5 1.0020 1.0020 1.0021 1.0021 1.0022 1.0022 1.0022 17.0 1.0021 1.0021 1.0022 1.0022 1.0023 1.0023 1.0023 17.5 1.0022 1.0022 1.0023 1.0023 1.0024 1.0024 1.0024 18.0 1.0022 1.0023 1.0023 1.0024 1.0025 1.0025 1.0025 18.5 1.0023 1.0024 1.0024 1.0025 1.0025 1.0026 1.0026 19.0 1.0024 1.0025 1.0025 1.0026 1.0026 1.0027 1.0027 19.5 1.0025 1.0026 1.0026 1.0027 1.0027 1.0028 1.0028 20.0 1.0026 1.0027 1.0027 1.0028 1.0028 1.0029 1.0029 20.5 1.0027 1.0028 1.0028 1.0029 1.0029 1.0030 1.0030 21.0 1.0028 1.0029 1.0029 1.0030 1.0031 1.0031 1.0031 21.5 1.0030 1.0030 1.0031 1.0031 1.0032 1.0032 1.0032 22.0 1.0031 1.0031 1.0032 1.0032 1.0033 1.0033 1.0033 22.5 1.0032 1.0032 1.0033 1.0033 1.0034 1.0034 1.0034 23.0 1.0033 1.0033 1.0034 1.0034 1.0035 1.0035 1.0036 23.5 1.0034 1.0035 1.0035 1.0036 1.0036 1.0036 1.0037 24.0 1.0035 1.0036 1.0036 1.0037 1.0037 1.0038 1.0038 24.5 1.0037 1.0037 1.0038 1.0038 1.0039 1.0039 1.0039 25.0 1.0038 1.0038 1.0039 1.0039 1.0040 1.0040 1.0040 25.5 1.0039 1.0040 1.0040 1.0041 1.0041 1.0041 1.0042 26.0 1.0040 1.0041 1.0041 1.0042 1.0042 1.0043 1.0043 26.5 1.0042 1.0042 1.0043 1.0043 1.0044 1.0044 1.0044 27.0 1.0043 1.0044 1.0044 1.0045 1.0045 1.0045 1.0046 27.5 1.0045 1.0045 1.0046 1.0046 1.0047 1.0047 1.0047 28.0 1.0046 1.0046 1.0047 1.0047 1.0048 1.0048 1.0048 28.5 1.0047 1.0048 1.0048 1.0049 1.0049 1.0050 1.0050 29.0 1.0049 1.0049 1.0050 1.0050 1.0051 1.0051 1.0051 29.5 1.0050 1.0051 1.0051 1.0052 1.0052 1.0052 1.0053 30.0 1.0052 1.0052 1.0053 1.0053 1.0054 1.0054 1.0054 Z correction factors are for distilled water as a function of liquid test temperature and air pressure. Z values are in microliters per milligram. Reprinted from ISO 8655-6:2002(E). If your laboratory does not have a mercury barometer, the true local barometric pressure for locations throughout North Carolina may be obtained from the North Carolina State University, State Climate Office of North Carolina website at http://www.nc-climate.ncsu.edu/. Weight Verification (NC WW/GW LC Policy 05/23/2008) ASTM Class 1 and 2 weights must be verified at least every 5 years. ASTM Class 1 weights (20 g to 25 kg) and ASTM Class 2 weights (10 g to 1 mg) are equivalent to the NBS Class S weights specified in 15A NCAC 2H .0805 (a) (7) (K). Verification may be accomplished by: 1. Sending laboratory weights back to the manufacturer for recertification - reference weights shall be calibrated by a body that can provide traceability to ASTM specifications, or 2. Checking laboratory weights against certified reference weights (i.e., weights that have been recertified as above) and found to be within ASTM Class 1 or Class 2 tolerances (see table below) - often the balance service technician may provide this service. Note: Although some manufacturers will assign a one-year calibration due date, 5 years is considered an acceptable calibration interval due to the limited use of the reference weight set. Documentation of weight verifications or recertification must be maintained for 5 years. I f the condition of a weight(s) is in question at any time due to damage (e.g., corrosion, nicks, scratching, etc.), the laboratory must have that weight(s) re-verified as described above. Maximum tolerances (Ref. ASTM E 617-97, 2003) Denomination Maximum tolerance for ASTM Class 1 and 2 weights, (± mg) 500 g 1.2 300 g 0.75 200 g 0.50 100 g 0.25 50 g 0.12 30 g 0.074 20 g 0.074 10 g 0.074 5 g 0.054 3 g 0.054 2 g 0.054 1 g 0.054 500 mg 0.025 300 mg 0.025 200 mg 0.025 100 mg 0.025 50 mg 0.014 30 mg 0.014 20 mg 0.014 10 mg 0.014 5 mg 0.014 3 mg 0.014 2 mg 0.014 1 mg 0.014