## Potline Emissions Laboratory Test Plan **(Revised 8/31/12)**

**Purpose** The Primary

Aluminum MACT promulgated October 7, 1997 set limits for control of fluoride emissions from aluminum production facilities. Among other requirements, the standard specificall y states that a written test plan must be developed that outlines and describes how the operator conducts performance testing to determine compliance with the MACT emission monitoring requirements. This document serves to describe the Ormet tes ting program to meet the test plan requirements as identified in 40 CFR 63.847 (b).
**Program Summary** Ormet operates six center work prebake aluminum reduction potlines. Each potline is subdivided into four quarters with each quarter containing 43 electrol ytic cells (pots). All potlines employ

the same center work prebake technology and are similarly

operated and maintained. Fluoride emissions from the reduction process are vented to a dry scrubber control sy stem. The primary components of the control sy stems include pot hooding, duct work, six alumina reactors, and associated baghouses and fans that induce draft through the s ys tem. Attached is a sketch of the overall arrangement of the potlines and control sy stems. One quarter of each potline is equipped with a USEPA Method 14A test monitor. The fugitive testing equipment is maintained and calibrated according to manufacturer’s specifications and procedures developed b y Ormet. The attached sketch shows each of the Method 14A fugitive testing locati ons within the potlines. Compliance with the applicable emission limit is determined on a monthl y basis by combining the monthly

average of the three fugitive test runs for a given potline using Method 14A with test results of the corresponding control sy stem obtained during the previous 12 months using EPA Method 13B. The total emission number is then divided by the metal produced for the potline. Emissions are calculated using the formulas and methodology

identified in Method 14A. **Summary of Test Sc hedule**  The Ormet laboratory

will perform three test runs per month per potline for fugitive total fluoride emission. These tests will normally be scheduled to occur simultaneously on all six potlines during the first three weeks of each calendar month. As required by 40 CFR 63.847 (b)(8), at least one run will be performed before the 15 th of the month, and at least one run is performed after the 15 th of the month and that there are at least 6 days betweentest runs. Fugitive tests runs will be 32 hour s in duration to match a complete operating

cycle for a potline of setting, tapping and alumina charging. The fluoride emissions from each of the six corresponding dry scrubber reactor sy stems are measured annuall y by a professional emission testing comp any. The specific dates of this testing have not been determined. As provided in 63.847 (c), Ormet may exercise the right to use performance tests conducted on the primary control sy stem during the 12 months prior to October 7, 2001 to demonstrate initial compliance. If Ormet chooses to exercise this option, the OEPA will be contacted at least 60 day s prior to the October 7, 2001 compliance date. **Sampling and Analytical Procedures** This test program is designed to characterize total fluoride emissions. The methods chosen are appropriate to the source type and are specified b y the EPA (40 CFR 63.849). Point source emissions will be measured using EPA Method 13B

– Determination of Total Fluoride Emissions from Stationary Sources (Specific Ion Electrode Method). Method 13B involves isokinetic sampling of gaseous and particulate fluoride from the source with sample collection in water and on a filter. Fugitive emissions will be measured using EPA Method 14A

– Determination of Total Fluoride Emission from Selected Sources at Primary Aluminum Production Facilities . In Method 14A, total fluorides are sampled prior to exiting the roof m o nitor using strategicall y placed sampling cassettes. The cassettes and the associated manifold system allow for uniform di stribution of sample volume through each cassette. Ormet’s manifold sy stem is a permanent fixture in the roof of each testing quarter, accessible by ladder and catwalk

. Each cassette consists of sandwiched filter media suitable for collecting both particulate and gaseous fluoride. Analy tical procedures for Methods 13B and 14A will be in accordance with the Analytical Procedures as specified in Section 11.0 of the respective methods.
**Data Quality Objectives** The overall objective of this test program i s to quantify the fugitive and point

- source emissions of total fluoride from the center

- worked prebake potlines during normal operation. To obtain data that satisfies this objective, this test plan is designed to meet specific standards for accuracy , prec ision, and completeness, as summarized in the following table. Data quality objectives for precision and accuracy will be assessed relative to laboratory

performance. Completeness will be assessed relative to both field and laboratory

activities, as discussed below.Sample Method Parameter Precision Accuracy Completeness

EPA M13B Total Fluoride ± 5 % RSD ± 10 % 100 % EPA M14A Total Fluoride ± 5 % RSD ± 10 % 100 %
Precision The precision of fluoride measurements obtained using EPA Method 13B and 14A will be assessed through laboratory analy sis of sample duplicates. For Method 13B and 14 A anal ys es , the laboratory will use standards of fluoride concentration to demonstrate analy tical precision. Standards will be prepared to contain fluoride concentrations that bracket the expected sample results. Laboratory precision will be considered acceptable if the duplicate results are within five percent relative standard deviation. Accuracy The accuracy

of the Method 13B analy ses will be determined by an alyzing EPA “blind” audit standards (see additional discussion under External Quality Assurance below). Similarly, blind audit samples will be prepared for the Method 14A analy ses. Accuracy objectives for this test program are to match audit sample total fluoride values within ten percent of the known concentration as suggested in Method 14A Section 9.0

– Quality Control. Completeness Completeness refers to the number of valid results compared to the number required b y the sampling program. EPA has established three test runs as the minimum number needed for statistical purposes. Sample runs will be considered to be complete when three successful runs, including requisite quality control measures, have been completed. Completeness of laboratory analy ses will be achieved when the requisite calibrations, anal ytical procedures, and data anal ys es have been completed as specified by the respective method.**Sample Custody Procedures**

Method 14A samples are handled only by Ormet in

- house laborato ry personnel and will not require chain

- of

- custody documentation. Method 14A samples are labeled with the following information: Potline number (Line 1

- 6), cassette position (position 1

- 8), and beginning date of test. Method 13B samples will be labeled w ith the following information: sample number, plant name, city and state, test location, test date, test number, EPA method, impinge solution, sample analy sis, ty pe of sample (front rinse, front filter, back rinse, back filter, back solution), technician n ame(s), and sample volume. Each Method 13B sample will be accompanied b y a chain

- of

- custody form. The chain

of

- custody form documents each person to either relinquish or receive the sample from the sampling location to the laboratory . The date and time of each transfer of the sample will be recorded. The method of shipping will be noted as well as the condition of the sample upon receipt at the laboratory

. **Internal Quality Assurance** Method 14A The Ormet in

- house laboratory analyzes all samples collec ted from fugitive testing. A Seal Auto Anal yz er III is used in the laboratory to determine the amount of fluoride present in each sample. This automated procedure is based on the utilization of hydrogen fluoride and the subsequent reaction of the distill ate with alizarin fluorine blue

- lanthanum reagent to form a lilac

- blue complex which is measured colormetricall y at 620nm. The Ormet program utilizes five samples of known concentration for calibrating the Auto Analyzer. These standards vary in fluoride concentration between 0.2 mg/l and 2.0 mg/l. At the end of a sample run a final calibration standard of 0.2 mg/l is anal yz ed to determine and compensate for any calibration drift. Standard operating procedures have been developed b y Ormet for use b y the lab anal yst. Field Sampling Equipment Quality Assurance Activities

– Method 14A **Equipment Activity**  **Frequency EPA Method**  Anemometer Calibration or

Replacement Yearl y Method 14A 10.3.1

– 10.3.3 Temperature Sensing and Recording Device Calibration or

Replacement Yearl y According to Manufacturer’s Specifications Flow Meter Calibration Yearl y Method 14A 10.1.4 Metering Sy stem Calibration Yearl y Method 14A 10.1Method 13B

A professional testing company is contracted to perform all tests on the primary control sy stem. The following table summarizes the quality assurance procedures that will be followed to ensure the field sampling (Method 13B) is performed in accordance wit h EPA requirements. Field Sampling Equipment Quality Assurance Activities

– Method 13B 

### Equipment **Activity Frequency**  **EPA Method** Differential Pressure Gauge Calibration After each field use 2 §6.2 Barometer Calibration Before each field use 2 §10 Pitot Tube, Ty

pe S Calibration After each field use 2 §10 Temperature Sensors Calibration After each field use 2 §10 Probe Heater Calibration Before each field use 5 §10 Probe Nozzle Calibration Before each field use 5 §10 Metering Sy stem Pre

- test Calibration 60 day s prior to testing 5 §10

In addition to these calibration activities, the respective EPA methods call for adherence to specific quality control procedures during field activities. These procedures include pre - and post

- test leak check s of the metering s ys tem, constant maintenance of filter temperatures within the specified 248 ± 25 °F, and constant monitoring of isokinetic sampling conditions (± 10% of true value). Laboratory

quality assurance procedures for Method 13B are summarized below. In general, laboratory

QA will include use of standards that are traceable to NIST standards and standardization of instruments according to method requirements.Laboratory Quality Assurance Activities

– Method 13B

**Equipment Activity**  **Frequency EPA Method** 

Fluoride Electrode Sequential anal ys is of standard

solutions (dilute to concentrated) and plotting of straight

- line calibration curve Daily with hourl y checks 13B § 10 Prepare fresh electrode standard

solutions Daily 13B § 10 Direct

- reading specific

- ion meter (if used) Calibrate according to

manufacturer instructions Daily 13B § 10
Prior to analy sis, sample loss checks and sample blank evaluations are also performed. During anal ys is with the fluoride electrode, laboratory temperature is monitored to ensure that fluctuations greater than ± 2 °C from calibration temperature do not occur. **External Quality Assurance** Method 14A Since the EPA currently

does not indicate the availability of Method 14A audit samples, audit sampl es will be prepared for each group of samples submitted for analy sis and will represent the concentrations that could be expected in the low, medium, and high range of audit results. To insure the accuracy of the results, three audit samples of known conc entration are anal yz ed with samples collected during a round of fugitive tests. Standard operating procedures have been developed by Ormet for use by

the lab anal ys t. Method 13B Method 13B total fluoride performance audit “blind” samples will be obtaine d from the EPA at least 45 day s prior to the test date. These samples will be obtained by completing an Audit Sample Request Form (available at the following internet site ) : http://www.epa.g ov//ttn/emc/audit/audreqr1.pdf The form will be faxed to the number appearing on the form (currentl y 919

- 541

- 1039). After faxing the form, a voice mail message will be left at (919) 541

- 0200 (or current number) to confirm the request. Laboratory analysi s of performance audit samples will be used to assess adherence to the data quality objectives for precision and accuracy of the Method 13B field testing.**Aluminum Production Rate**

The aluminum production rate is determined b y dividing the number of hours in a calendar month into the total weight of the aluminum tapped from a potline for the month. The aluminum production rate is monitored during the transport of molten metal in crucibles from the potlines to the cast house, where the scale is located. The gross weight of each crucible is measured and recorded electronically as it enters the cast house. Once the metal has been removed, the tare weight of the crucible is determined and electronicall y recorded. Th is gross and tare weight is used to calculate a net weight of aluminum which is credited by crucible and cast code to the potline from which it originated. This data is calculated and stored in a computerized database. The scales used for weighing the aluminum crucibles are certified on a monthly basis to an accuracy

of ± 5 lbs. The average weight of the metal in a crucible is 5,800 pounds. This gives each measurement a relative accuracy of ± 0.09%.