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Home My WebLink About#70-final (4) INSPECTION REPORT ROUTING SHEET To be attached to all inspection reports in-house only. Laboratory Cert. #: 70 Laboratory Name: Roanoke Rapids, Roanoke River WWTP Inspection Type: Municipal Maintenance Inspector Name(s): Todd Crawford Inspection Date: July 9, 2009 Date Report Completed: July 13, 2009 Date Forwarded to Reviewer: July 13, 2009 Reviewed by: Ramon Cook Date Review Completed: July 20, 2009 Cover Letter to use: Insp. Initial X Insp. Reg. Insp. No Finding __ Insp. CP Unit Supervisor: Dana Satterwhite Date Received: July 30, 2009 Date Forwarded to Alberta: August 21, 2009 Date Mailed: _____________________________________________________________________ On-Site Inspection Report LABORATORY NAME: Roanoke Rapids, Roanoke River WWTP ADDRESS: 135 Aqueduct Road Weldon, NC 27890 CERTIFICATE #: 70 DATE OF INSPECTION: July 9, 2009 TYPE OF INSPECTION: Municipal Maintenance AUDITOR(S): Todd Crawford and Tony Hatcher LOCAL PERSON(S) CONTACTED: Greta Glover 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 lab was generally clean and well organized. All equipment appeared well maintained. Findings C and F are new requirements since the last inspection. III. FINDINGS, REQUIREMENTS, COMMENTS AND RECOMMENDATIONS: Documentation A. Finding: Temperature logs are not being maintained on the weekend days when unanalyzed and/or in-progress samples are affected. Requirement: Each day an incubator, oven, waterbath or refrigerator is used, the temperature must be checked, recorded, and initialed. During each use the autoclave maximum temperature and pressure must be checked, recorded, and initialed. Ref: 15A NCAC 2H .0805 (a) (7) (J). B. Finding: Several instances of improper error corrections were observed. Requirement: All documentation errors must be corrected by drawing a single line through the error so that the original entry remains legible. Entries shall not be obliterated by erasures or markings. Wite-Out®, correction tape or similar products designed to obliterate documentation are not to be used. Write the correction adjacent to the error. The correction must be initialed by the responsible individual and the date of change documented. All data and log entries must be written in indelible ink. Pencil entries are not acceptable. Ref: North Carolina Wastewater/ Groundwater Laboratory Certification Policy. Page 2 #70 Roanoke Rapids, Roanoke River WWTP Coliform Fecal - Standard Methods, 18th Edition, 9222 D (MF) C. Finding: Consumable material comparison testing is not being performed with five replicate analyses. Comment: Current testing is on three replicates. Requirement: It is required that when a new lot of culture medium, pads, or membrane filters is to be used, a comparison of the current lot in use (reference lot) against the new lot (test lot), be made. As a minimum, make single analyses on five positive water samples. Ref: Standard Methods, 18th Edition, 9020 B. (3) (d). (See attached document for guidance.) Ammonia Nitrogen - Standard Methods, 18th Edition, 4500-NH3 F D. Finding: The percent difference between distilled and undistilled samples in the distillation study were routinely greater that 20%. This would require that all samples be distilled prior to analysis. This is not being done. Requirement: Any time quality control results indicate an analytical problem, the problem must be resolved and any samples involved must be rerun if the holding time has not expired. Ref: 15A NCAC 2H .0805 (a) (7) (F). Comment: The distilled sample concentration was not always the higher of the two. This inconsistency may due to the fact that the analyses of the distilled and undistilled sample portions are not being performed by the same lab. Recommendation: It is advisable that the distilled and undistilled sample portions used for the distillation study be analyzed by the same lab, using the same instrument, technology and methodology to minimize uncertainty introduced by the analysis, yielding a truer representation of the effect of matrix and the distillation process on sample results. E. Finding: Two mL of Ionic Strength Adjuster (ISA) solution is being used to elevate the pH to above 11 without adjusting the final calculation. Comment: The ISA solution is used in place of the 10N NaOH solution. Requirement: Record volume of 10N NaOH added in excess of 1 mL. Ref: Standard Methods, 18th Edition, 4500-NH3 F. (4) (e) and (5). Residue Suspended - Standard Methods, 18th Edition, 2540 D F. Finding: A minimum dried residue weight gain of 1 mg is used to determine the reporting limit. Requirement: Choose sample volume to yield between 2.5 and 200 mg dried residue. If volume filtered fails to meet minimum yield, increase sample volume up to 1 L. If complete filtration takes more than 10 minutes increase filter diameter or decrease sample volume. Ref: North Carolina Page 3 #70 Roanoke Rapids, Roanoke River WWTP Wastewater/Groundwater Laboratory Certification Policy, based upon Standard Methods, 20th and 21st Editions, 2540 D. (3) (b). Comment: Since the publication of the Code of Federal Regulations, Title 40, Part 136; Federal Register Vol. 72, No. 47, March 12, 2007, there is no longer an approved method that allows for a 1 mg weight gain. Currently, the minimum weight gain allowed is 2.5 mg. In instances where the weight gain is less than the required 2.5 mg, the value must be reported as less than the appropriate value based upon the volume used. For example, if 500 mL of sample is analyzed and < 2.5 mg of dried residue is obtained, the value reported would be < 5 mg/L. The minimum reporting value is now established at 2.5 mg/L based upon a sample volume used of 1000 mL. Total Residual Chlorine - HACH Method 10014 Recommendation: In addition to the annual 5-point curve verification, the lab is also running a daily 3-point curve and 2nd source standard. Only a single, mid- point standard, each analysis day, is required. IV. PAPER TRAIL INVESTIGATION: No paper trail was performed. 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: Todd Crawford Date: July 13, 2009 Report reviewed by: Ramon Cook Date: July 20, 2009 Ammonia Distillation Study Guidance It is advisable that the distilled and undistilled sample portions be analyzed by the same lab, using the same instrument, technology and methodology to minimize uncertainty introduced by the analysis, yielding a truer representation of the effect of matrix and the distillation process on sample results. In the case of low concentration effluents, the samples must be spiked to allow for a meaningful statistical comparison. It is recommended that samples with a concentration < 1.0 mg/L be spiked to yield a value in the 1 – 5 mg/L range. Comparisons performed in this concentration range should check within 20% RPD. Additional samples must be analyzed comparatively if the results do not indicate approximately the same values for distilled and undistilled samples. It is recommended that both the distilled and undistilled portions of the sample be analyzed by the same laboratory using the same methodology. The following frequencies are required: Municipal and Industrial Laboratories shall analyze initially four samples distilled and undistilled from each discharge and; thereafter, analyze two samples a year from each effluent. Commercial Laboratories shall analyze initially at least six samples distilled and undistilled, but at least two samples from all waste types. Analyze one sample distilled and undistilled yearly from all wastes types. Ref: North Carolina Wastewater/Groundwater Laboratory Certification (NC WW/GW LC) Policy, 01/15/2009; based upon Code of Federal Regulations, Title 40, Part 136; Federal Register Vol. 72, No. 47, March 12, 2007; Table 1B Footnote 6. Revised 09/2008 Testing of Consumable Materials for Fecal Coliform MF Method Standard Methods requires that before a new lot of consumable materials are used for the Fecal Coliform MF method, those materials be tested to ensure they are reliable. North Carolina policy requires the testing of the following consumable materials before they can be used for sample analyses: membrane filters and/or pads (often packaged together) and media. Test only one consumable at a time. REQUIREMENT: It is required that when a new lot of culture medium, pads, or membrane filters is to be used, a comparison of the current lot in use (reference lot) against the new lot (test lot), be made. As a minimum, make single analyses on five positive samples. Ref: Standard Methods, 18th Edition - Method 9020 B.3d. (page 9-7). The following is provided as guidance in performing the required testing. Let’s say you got a new batch of membrane filters in. We will call the currently used filters lot #1 and the new filters lot #2. 1. Select a culture positive sample. What you want is something that will yield 20-60 colonies when a reasonable sample volume is filtered. This may be a stream sample or a sample taken somewhere within the waste treatment plant. If the concentration is high enough that greater than 60 colonies are obtained when 1 mL is filtered then the solution is too strong and must be diluted. Any time a sample is diluted be sure it is done with the BUFFERED dilution water used for rinsing the funnels. 2. Test the culture positive to determine the appropriate volume to use. When collecting the culture positive sample do not think about it as a sample. You do not have to be concerned with a sterile sample bottle or 6 hour hold time. Collect enough sample so that you have plenty to work with, probably more than your normal fecal bottle holds. Set a series of dilutions using the currently used materials, in this example filter lot #1. Do not use the materials you want to prove are OK at this point. All you are trying to do is to determine the volume of sample that will yield 20-60 colonies. Put the rest of the sample in the refrigerator. For example: Volume used Colonies obtained on lot #1 filters 50 ml TNTC 25 ml 138 10 ml 50 5 ml 22 1 ml 4 Based on this preliminary testing it appears that a 10 ml volume would probably be appropriate to use and will yield the desired 20-60 colonies. Remember when you do the actual consumable test, the culture positive sample will be 24 hours old and the results you obtain may be lower than the initial results yielded, but not so significantly lower as to change your dilution choice. It is better to have your initial results on the high side of the 20-60 range for this reason. In this example the 5 ml volume would probably be too low and would likely yield less than 20 colonies the next day. 3. Perform the consumable test Once you determine the appropriate volume, in this case 10 mls, take the remaining culture positive sample from the refrigerator, bring to room temperature and set five 10 ml plates with the currently used filters, lot #1, and five 10 ml plates with the new filters, lot #2. Revised 09/2008 4. Determine acceptability of new material For example: Lot #1-current filters Colonies obtained on lot #1 filters 10 ml 48 10ml 45 10 ml 50 10 ml 44 10 ml 43 Average: 46 Lot #2-new filters Colonies obtained on lot #2 filters 10 ml 40 10ml 45 10 ml 38 10 ml 46 10 ml 37 Average: 41 When determining the acceptability of the new material, compare the average of the five replicates for lot #1 to the average of the five replicates for lot #2; that is 46 vs. 41 colonies. The recommended acceptance criteria would be your current acceptance criteria used for your Fecal Coliform duplicates. If the test and reference materials check within what you have determined is acceptable for duplicates of samples, the test material would be considered acceptable to use. This may be a calculated acceptance criteria based on 3 times the standard deviation of the mean or a set value like 20% RPD. No matter how you determine your duplicate acceptance criteria make sure you use colony counts not final calculated values in doing this. Other factors to consider when determining if a new material is suitable include: Are the colonies obtained typical, that is normal looking blue colonies? Are the colonies evenly distributed across the membrane surface? Are there an unusual number of non typical colonies present? Is there a pattern to the colony recoveries? For example are all the plates for the test materials significantly lower in counts than the reference lot? It is recommended that new consumables be tested as soon as possible after receipt to avoid problems if the materials are not acceptable. Once you determine that the new material is acceptable to use; you may begin to do so. Document the date the new lot # is put into use. Revised 2/06