Sampling and Field Testing at Wastewater Treatment Facilities

Transcription

1 Sampling and Field Testing at Wastewater Treatment Facilities

2 Summary Where to find the information Sampling procedures Field testing and meter calibration

3 Where to find the information Wastewater Permit, Part I, Monitoring F.A.C Wastewater Monitoring Rule F.A.C Quality Assurance Rule Field DEP SOP - 001/01 revised on February 1, m.pdf

4 Where to find information, cont. SOP - FD 1000 Documentation SOPs / Sampling FC 1000 Field Decontamination FQ 1000 Quality Control FS 1000 General Sampling FS 2000 General Water Sampling FS 2400 Wastewater Sampling SOPs / Testing FT 1000 Field Testing General FT 1100 Field ph FT 1600 Field Turbidity FT 1800 Field Flow Meters FT 1900 Field Continuous Monitoring FT 2000 Field Residual Chlorine other

5 Sampling Points As described in the permit Influent (prior to any plant process recycled water) CBOD5, TSS effluent after filtration before disinfection Turbidity and TSS for high level disinfection effluent after chlorination most sampling, including CBOD 5, TSS, nutrients, TRC (check if 15 minutes retention time is assured), and other per permit requirements effluent after the final treatment (e.g.,after dechlorination) per NPDES permit requirements, usually TRC, DO, other

6 Sampling Types Grab samples grab directly into a sample container or with intermediate vessel like dipper or bucket submerge container neck first invert bottle so the neck is upright pointing into the water flow add preservative, cap container and label FC, VOC, un-ionized ammonia are always grab samples Time composite samples (seldom required) Flow- proportioned composite samples an automatic sampler and associated flow measuring device manually, size of the aliquot determined with a flow chart collect a minimum of 100 ml for each aliquot

7 Sampling Types, cont. How to collect a representative sample center of the flow where velocity is highest % of the total depth (except FC) if collecting from a sample tap allow the sample to run for one to two minutes Quality Control samples Field blanks are collected to: monitor on-site sampling environment, sample container cleaning, the suitability of sample preservatives and analyte-free water, and sample transport and storage conditions. blanks are not required for microbiological samples and CBOD 5 collect equipment blanks at a frequency of 5% of the samples or at a minimum 1 per year per test/matrix field duplicates are not mandatory unless required by an analytical method

8 Sampling Containers DEP SOP Table FS and 40 CFR Part 136 Table II Nutrients, CBOD, TSS: plastic or glass Coliforms: plastic or glass, sterile Turbidity: plastic or glass Metals: usually plastic, glass is accepted except for boron, chromium IV, and mercury Oil & grease: glass, wide mouth Organics: glass with teflon lined cap

9 Sampling Equipment Select sampling equipment based on the parameters of interest, Table FS and FS For TSS, CBOD and nutrients use: teflon, polyethylene, polypropylene, stainless steel, carbon steel, glass, tygon, viton, silicone, neoprene, and PVC. For metals use: teflon, polyethylene, polypropylene, stainless steel, glass (except silicon and boron), tygon, viton, silicone, neoprene, and PVC For micro use: teflon, stainless steel, polyethylene polypropylene, glass, tygon, viton, silicone, neoprene, and PVC

10 Sampling Equipment, cont. Additional concerns, composite samplers temperature in a composite sampler must be maintained between 1-4 o C sampler cleaned and maintained properly change tubing every 6 months or if discolored or lost elasticity complete purging must be accomplished before each aliquot collection minimum tubing size 1/4 inch inside diameter to prevent clogging pumping velocity must be sufficient to prevent solid settling (2 feet per second)

11 Sampling Equipment, cont. Decontamination of sampling equipment and containers DEP SOP FC 1000 generally, sampling containers should be washed with hot tap water and laboratory-grade detergent, rinsed with tap water, rinse with 10% nitric acid (for metals) and hydrochloric acid for nutrients and other parameters, rinsed again with analytefree water (DI water) for microbiological samples,if possible, collect directly into a sampling container; sampling containers have to be sterile, do not rinse sample container with the sample water. Intermediate sampling equipment has to be thoroughly cleaned and rinsed several times with sample water before collection; intermediate sampling equipment does not require sterilization;

12 Sample Preservation Follow table 4 in SOP FS 1000 for required containers, preservation techniques, and holding times Generally, preserve samples: within 15 minutes from sample collection cool to 4 o C by placing it on ice Add preservative/treatment H 2 SO 4 for TP, ammonia, TKN, NO 3 +NO 2 to ph less than 2 HNO 3 for metals to ph less than 2 Na 2 S 2 O 3 for fecal coliforms to dechlorinate sample notice: no chemical preservation required for TSS, CBOD 5, and NO 3, just cooling

13 Sampling Records Use waterproof ink for all paper documentation Make corrections by marking a line through the error so that it is still legible. Initial or sign the marked error Date and time of sample collection; if composite samples then date and time of first and last aliquot Name of the person collecting sample Site address Description of sampling site (e.g. effluent from CCC) Field ID number for each container Number of containers Analyses required Preservative used

14 Sampling - Summary During inspection check if: sampling points are consistent with permit requirements representative samples are being collected appropriate type of sample is collected (grab/composite) applicable field blanks are collected sample containers and sample equipment is made of appropriate material sample preservation and holding time sample transport/storage records, including sample kit preparation, sampling, preservation, sample custody questions?

15 Field Testing and Certification No certification by the DOH ELCP is required when conducting the following test procedures: ph Dissolved oxygen Specific conductivity Temperature Total residual chlorine (including free available chlorine) Turbidity (when performed at the sampling location) Sediment oxygen demand Any other test with a specific holding time of fifteen minutes or less when performed at the sampling location Any analyses related solely to internal process control

16 Field Measurements - ph Sample location - after final treatment ph meter requirements meter consisting of potentiometer, glass electrode, reference electrode, and temperature compensating device low sodium electrode should be used for samples at ph 10.0 accurate and reproducible to at least 0.2 unit in the range of 0.0 to 14.0 units calibration calibrated with at least two ph buffers always use ph buffer 7.0 first buffers must bracket the expected sample ph second buffer must be at least three ph units apart (4.0. or 10.0) if third calibration point needed and instrument cannot be calibrated with three buffers, use the third buffer as a calibration check

17 Field Measurements - ph cont. ph continuous meters initial calibration before installation and each time the instrument is taken off-line after fails QC criteria daily checks measure ph of a grab sample taken at the same location as in-line monitor, or check directly with a buffer compare measurements, difference should be no more that 0.2 ph (0.1 for the EPA)

18 Field Measurements - TRC Grab - Total Residual Chlorine EPA approved methods are DPD, colorimetric (most common) recommended for levels titration colorimetric titration amperometric - when DPD not applicable or feasible (e.g., color interference, low Cl level) color wheel comparators are not allowed for wastewater samples

19 Field Measurements - TRC cont. Calibration and daily checks for DPD colorimetric method instrument: spectrophotometer at wavelength 515 nm and light path of 1 cm or longer or filter photometer with maximum transmission at nm and light path 1 cm or longer that can be calibrated with a blank and at least one standard manufacturer calibration has to be initially confirmed with a blank and three primary (chlorine or potassium permanganate) standards colorimeter/spectrophotometer has to be checked daily with at least one standard gel standards and meters, used for daily checks, have to be checked quarterly against primary standards, gel standards cannot be used to check meters at low range

20 Field Measurements - TRC cont. Total Residual Chlorine Analyzer initial calibration before installation and each time the instrument is taken off-line after fails QC criteria daily checks measure TRC of a grab sample taken at the same location as in-line analyzer, or check directly with a standard compare measurements, difference should be no more than 20% between samples (10% if standard)

21 Field Measurements - Turbidity Meter specifications; EPA Method the light source must have a tungsten-filament lamp operated between 2000 and 3000 o K the distance traversed by the incident light and scattered light within the sample tube must not exceed 10 cm the light detector positioned at 90 o to the incident light, must have an acceptance angle that does not exceed ±30 o from 90 o. the detector and any filter system must have a spectral peak response between 400 and 600 nanometers the instrument sensitivity must permit detection of a turbidity difference of 0.02 NTU at the NTU scale

22 Field Measurements - Turbidity Calibration requirements follow the manufacturer s operating instructions primary (formazin) or secondary (gel type) standards can be used for daily checks or calibrations run at least one standard in each instrument range to be used in field secondary standards must be checked quarterly against a primary standard

23 Field Measurements - Turbidity In-line Turbidimeter initial calibration before installation and each time the instrument is taken off-line after fails QC criteria daily checks measure turbidity of a grab sample taken at the same location as in-line analyzer or, measure turbidity of a standard in the same range compare two measurements, difference should be no more than 20% (10 % if checked with a standard)

24 Field Measurements - other tests Dissolved Oxygen follow SOP FT 1500 use a membrane/electrode DO meter with accuracy of ± 0.2 DO mg/l and sensor with automatic temperature compensation before use check the meter in water-saturated air periodical checks against Winkler method may be required keep records of the calibrations, checks, sample measurements check in-line continuous DO meter daily (or as often as reported on the DMRs) against a second meter; the difference should be no greater than 0.2 mg/l

25 Field Measurements - other tests Specific Conductance follow SOP FT 1200 use meter with platinum or graphite electrode and temperature sensor calibrate the meter keep records of calibrations, sample measurements and temperature make sure to perform a temperature correction to 25 o C using formula given in the SOP (if not done automatically) check in-line continuous conductivity meter daily (or as often as reported on the DMR) against a second meter; the difference should be no greater than 10%

26 Field Measurements - other tests Temperature follow the DEP SOP FT 1400 field instrument must be capable of measuring temperature in 0.1 o C increments several instruments can be used: digital thermistor, glass bulb mercury or alcohol filled, BI-metal strip, or advanced silicon chip temperature sensor check thermometric device against an NIST-traceable thermometer; temperature should agree within ±0.1 o C determine the maximum time between continuing verifications based on the instrument stability (EPA requires annual check) keep records of calibrations/checks and samples measurements additional EPA requirements: thermistors should be checked against a NIST traceable thermometer prior to use and should agree within ± 4.0 C. This includes, but is not limited to, the ph, conductivity, and DO meters.

27 Records Records of calibration procedures date and time and location of the calibration and a field check if applicable name of the person performing calibration standards and ph buffers used actual reading of buffers / standards after the calibration corrective actions if applicable meter name and model number Reagent and standards documentation date and time of the receipt, expiration dates if any standard or chemical is used after the expiration date, there must be a documentation showing that the reagent is providing an acceptable response

28 Records, cont. Records of field measurements date and time the measurement was collected location of the sample sample value and unit initial of the person taking the measurement Records of daily comparability checks date and time location reading from the continuous meter reading from the second meter difference no greater than 20% (turbidity and TRC) difference no greater than 0.2 ph units (EPA requires 0.1) name of the person performing the check

29 Summary Field Testing Field test methods Hand-held field meters In-line, continuous meters Calibration requirements Daily checks of in-line meters Records calibration procedures daily checks comparability checks sample measurements standards Questions?