### ~1:::11211 ELECTRIC POWER 1::1- RESEARCH INSTITUTE Memorandum
Date: May 16, 2007
TO: RonJordan, EPA FROM: Naomi Goodman, EPRI SUBJECT: 

### SUPPLEMENTAL INFORMATION: SAMPLINGCOAL-FIRED ELECTRICPOWERPLANTWASTEWATERS The following information provides a detailed discussion ofbestpractices for collection of wastewater samples during the EPA SteamElectric Power Generating Point Source Category sample collection effort. This memorandum supplements EPRI's documentSamplingand AnalyticalPlan Guidance for Water Characterization ofCoal-FiredSteam Electric Utility Facilities, March 2007. Topics covered in this memorandum include best sampling practices for each wastewatermatrix, collection ofsplit samples, and otherrecommendations. 

### Summary of Sampling Recommendations 

### by Wastewater Stream EPA's Generic SamplingandAnalysisPlanfor Coal-FiredSteam ElectricPowerPlants, May 11, 2007identifies six target wastewaters. Supplemental guidance on sampling and analysis for the EPA target wastewaters and otherpotential sampling locations is summarized below. 

### AshPondInfluent Identifying the best sample location in an ashpond can be challenging, and will be site-specific. It maynotbepossible to find one spot where all flow into an ash pond is mixed together, especially ifinfluentpipes come in at differentpoints along the ash pond shoreline. Ifall inputs to the pond combine into a single flow and are channelized within the ash delta, it maybe possible to collect a sample at the downstream (in-pond) end ofthe ash delta. This will depend upon accessibility and plant safety requirements. The ash pond int1uent sample should be collected as a composite, due to variations in the t1ow into a pond \vith sluice cycling and other plant processes. Composites can be collected with an automatic sampler orby pooling multiple manual grab samples collected over time. Ifmanual composites are used, the composite should encompass at least one sluice cycle. Ifautomatic compositers are used, a 24-hour composite can be collected. In this case, care will be needed toposition the sampling suction line to avoid clogging and to checkto ensure water is being collected. Summary ofSampling Recommendations for Wastewater Streams Sample Clean or Recommended Analytical Considerations Location Conventional Sample Type Sampling Ash Pond Conventional Composite, due Will have high solids and possible Influent to variations in chemical interferences sluicing Ash Pond Clean Grab Samples should be low in suspended Effluent solids (<30 mg/L), andrelatively low in matrix interferences (unless FGD discharges to pond). FGD Treatment Conventional Composite (see Will have high solids and chemical System Influent discussion interferences below) FGD Treatment Clean Grab (assuming Will have high chemical interferences System After system has Primary equalization Clarification tank) FGD Treatment Clean Grab (assuming Will have high chemical interferences System Effluent systemhas equalization tank) Final Effluent Clean Grab Expect low matrix interferences Source Water Clean Grab Expect low matrix interferences Ifa sample must be collectedbefore bulk ash settling (i.e., early in the delta), the composite shouldbe shaken and then allowed to settle for 1hourpriorto decanting the supernatant sample containers. Itis recommended that filtering for dissolved metals analysis be done bypumping some ofthe composited sample, after settling, through anin-line cartridge filter into sample containers. 

### AshPondEffluent Samples shouldbepumped directly from the ash pond discharge stream. Compositing is not essential, due to mixing within the pond. Filtering for dissolved metals analysis should be accomplishedbypumping water from the pond through an in-line cartridge filter into cleaned sample containers. I

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Itis recommended that filtering for dissolvedmetals analysisbe accomplished bypumping some ofthe sample through a filter into sample containers. 

### FGD TreatmentSystem Influent FGDblowdown quality maybe highly variable in flow and composition, and contains high solids. Samplers should consultthe FGD system operators during the site reconnaissance to answerthe following questions: • Does FGD wastewater flow continuouslyto the treatment system? • Does flow vary overtime? • Is solids loading inthe FGD wastewater consistent, ordoes it change with time orfuel changes? The answers to these questions will determine the amount ofcoordination with operators that will be required in collectingthe sample. A composite sample is recommended. The composite should consist ofa series ofgrab samples, collected overtime and mixed together in a large container. A manual composite is recommended rather than an automatic samplerat this location, because the high-solids stream (potentially 5% ormore) couldplug an automatic sampler's suction hose. Itis recommendedthat filtering for dissolved metals analysis be done bypumping some ofthe composited sample, after settling, through an in-line cartridge filter into sample containers. Samples should not be collected from the treatment system equalization tank ifany liquid or sludge streams otherthan FGD blowdown are dischargedto the tank. Operating data and observations ofthe wastewaterflow and color shouldberecorded during sampling, as these observations will be criticalto interpretation ofthe analytical results. 

### FGD TreatmentSystem Mid-Point(AfterPrimary Clarification) andEffluent Samples shouldbe taken directly from a sampling tap orpumped directly from the effluent tank. Assuming there is anequalizationtank in the system, compositing is not essential. Ifsampling from a tank, samples should be collected bypumpingratherthan dipping, to avoid collecting floating materials. Ifsampling from a tap, it is recommended to collect samples for dissolved metals analysis by filling a cleaned container from the tap, mixing the collected water, and then pumping the collected water through an in-line cartridge filter into sample containers. Extra filters should be made available, as solids in the effluent may plug the filter. 

### FinalEffluent Samples should be collected directly from the effluent discharge. Compositing is not essential unless multiple discharge points arc sampled at one facility. Filtering for dissolved metalsanalysis should be accomplishedbypumping water from the effluent location through anin-line cartridge filter into sample containers. Ifsamples are collected from a sample tap, it maybe better to collect into a clean container, and then filter through the filter cartridge. 

### Source WaterSamples In orderto determine the amount ofpollutantsthat are contributed from the source waterbody, a source water sample shouldbe collected. This sample should be collected and analyzed using trace level clean techniques. Ifdissolved samples are to be collected, the sample shouldbe pumpedthrough a filter cartridge. Ifsamples are collected from a sample tap, it maybe betterto collect into a clean container, and then filter through the filter cartridge. 

### Collection of Split Samples The goal ofsplit sample collection is to generate paired samples that represent the same water composition as closely as possible. The recommendedtechniques for preparing splits are: 1. Pumped samples (effluents and otherrelatively low solids streams)- use a Y-splitterto simultaneously collectpaired samples for eachparameter. An equal flow should be routed into each ofthepairedbottles. Pre-cleanedY-splitters and pump tubing should be provided for each sampling location and discarded after sampling is completed, to avoid cross-contamination. Oil and grease (HEM/SGT-HEM) should not be sampledthrough a splitter. 2. Pumped or grab samples (high solids streams) excluding solids, and filtered samplescollect sufficient sample for paired bottles into apre-cleaned, dedicated containerlarge enough for both the EPA and split sample volume. Shake container ormixthe water thoroughly with an agitator, let settle, and pump from the supernatantthrough a Y-splitter into paired sample bottles. 3. Pumped or grab samples (high solids streams) including solids -collect sufficient sample for paired bottles in a pre-cleaned, dedicated container large enough for both the EPA and split sample volume. Shake container or mixthe waterthoroughlywith an agitator, and while still well mixed, pump through a Y-splitter into paired samplebottles. The total volume that mustbe collected at each sampling location is calculated inAttachment A. The volume was calculated from Table 2-3 in the EPA's Generic Sampling and Analysis Plan, May 11, 2007. Itwas assumed for these calculations that a field duplicate ofthe split samples will notberequired, and that MS/MSDs for the split samples will beprepared from the same container as the parent sample. The total volume ofsample required at each sampling location if samples will be submitted for clean metals analysis is 27.4 liters (7.2 gallons). Ifonly 200-series metals analyses will berequired, the total volume is 19.4liters (5.1 gallons). To collect a composite sample sufficient for all parameters and splits, a large container will be needed, such as a plastic carboy orbucket ofappropriate materials, cleanedper specifications of the clean sampling methods. Composites should be kept on ice while they are being collected; a larger outer container full ofice can be placedaround the container used to collect the composite. 

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Other Field Sampling and Analytical Considerations • Ensure that sufficient ultrapure, analyte-free water is sent from the laboratory for preparing blanks. Forexample, ifabottle blank, field blank and equipmentblank are to be collected for the full suite ofparameters in EPA'splan, at least 32 liters ofwater from the laboratory will be needed. • Guidance should be given to analytical laboratories on which samples are from the FGD wastewater (influent, midpoint and effluent) and ashpond influent locations, as these will likelypose matrix interference challenges for the laboratory. • Itis recommended that at least one sample ofeach matrix (FGD water, ash pond water) be collected in advance ofthe EPA site sampling visits, so that the EPA laboratory can practice working with the matrices involved to help avoidproblems with the actual samples.

Cc: P. Chu, EPRlAttachment A. Total Sample Volume Requirements for EPA and Split Samples into One Collec t ion

Container . : " , .,_ · · "' . ; ,,. EPA EPAQC Split Split Total

' ;

Low-Level ' •' ' , Sarqpl e Volume MS / Volume

. '

Method? Parameter ; . MSD* "' (L)

Classical BOD 5 1 1 X X

Group I (a) 1.5 1.5 1.5 X

Group II (b) 1.1 ** 2 I X

HEM / SGT-HEM I 2 X X

Metals

X Low-level total mercury (Method 163 1) 0.5 0.5 0.5

X Low-level dissolved mercury (Method 1631) 0 . 5 0 . 5 0 .5

X Low-level tota l elements by ICP / MS 0.5 0.5 1

(9 elements, Method 1638)

X Low-level dis so l ve d elements by I CP / MS 0.5 0 . 5 1

(9 elements, Method 1638)

X Low-level hexavalent chromium (Method 1 636) 0 . 5 0 .5 1

Routine hexavalent chromium 0 . 2 0 . 2

Total metals , 27 element quantitation 0.5 0.5 I

(Methods 200 . 7, 200.8, 200.9) Dissolved metals, 27 element quantitation 0.5 0 .5 I

(Methods 200 .7, 200 . 8, 200 . 9) Speciation of As and Se X X 0.375

TOTAL VOLUME without Low-Level Metals (liters) 5.8 7 . 7 5 .9 1 9.4

TOTAL VOLUJ\!E with Low-Level Metals (liters) 8.3 10.2

.__ 9.0 27.4

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(a) Group I includes TSS, TDS, sulfate, and chloride.

(b) Group II includes ammonia as nitrogen , nitrate / nitrite as nitrogen, TKN, and total phosphorus . I

*-Note: It is recommended that matrix spike I matrix spike duplicates be collected in the same bottle as the nati v e sample , with a larger bottle use d to ens u re

sufficient volume . This is recommended in order to ensure that the same matrix is collected .

**- per EPA Sampling Plan ...