United QtatM
Environmental Protection
Agtncy
Office of Air Quality
Panning and Standards
Research Triangle Park, NC 27711
EMB Report 31-CEP-18
Vduma I
Oacamber 1991
Air
Hexavalent Chromium
Emission Test Report
Precision Engineering Company
Seattle, Washington
e of Air
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HEXAVALENT CHROMIUM EMISSION EVALUATION
PRECISION ENGINEERING, INC.
SEATTLE, WASHINGTON
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
EMISSION MEASUREMENT BRANCH
RESEARCH TRIANGLE PARK, NORTH CAROLINA
EPA Contract No. 68-D-90155
DECEMBER 31, 1992
Prepared by
ADVANCED SYSTEMS TECHNOLOGY, INC.
3490 Piedmont Road, NE • Suite 1410
Atlanta, GA 30305-4810
(404)240-2930
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TABLE OF CONTENTS
**##*********************++****************************
Sections Pages
TABLES and FIGURES
EXECUTIVE SUMMARY i-iii
Section 1 INTRODUCTION 1-1
Section 2 PROCESS OPERATION 2-1
2.1 Process Description 2-1
2.2 Air Pollution Control Device 2-2
2.3 Process Conditions During Testing 2-4
Section 3 SUMMARY OF SAMPLE COLLECTION,
EMISSION CALCULATIONS AND RESULTS 3-1
3.1 Sample Collection 3-1
3.2 Stack Gas Parameters 3-1
3.3 Emission Calculations and Discussion of Results 3-2
3.3.1 Cr-VI Results From Colorimetry and ICPCR Analyses 3-4
3.3.2 Total Chromium Results From ICP Analysis 3-4
3.3.3 Concentrations In Plating Tank Solution,
MPME Water and Train Blank Samples 3-8
3.3.4 Computerized Spreadsheet Calculations 3-8
3.3.5 Removal Efficiency of The Mesh Pad Mist Eliminator 3-8
3.3.6 Penetration of The Mesh Pad Mist Eliminator 3-10
Section 4 SAMPLING AND ANALYSIS METHODS 4-1
4.1 Types of Samples Collected and Sample Recovery Descriptions 4-1
4.1.1 Liquid Grab Samples 4-1
4.1.2 Gaseous Stack Samples 4-1
4.1.3 Sampling Locations 4-2
4.2 Air Sampling Test Methods 4-7
4.2.1 Traverse Points 4-7
4.2.2 Stack Gas Velocity 4-7
4.2.3 Stack Gas Moisture 4-7
4.2.4 Modified Method 13-B Sampling Train 4-8
4.3 Sample Analysis Methods 4-8
4.3.1 Colorimetry 4-10
4.3.2 Inductively Coupled Plasma (ICP) 4-10
4.3.3 lon-Cnromatography With Post Column Reactor (ICPCR) 4-10
Section 5 QUALITY ASSURANCE PROGRAM, TEST PROGRAM
PERSONNEL AND SUMMARY OF FIELD ACTIVITIES 5-1
5.1 Quality Assurance Program 5-1
5.2 Data Review Prior To Report Preparation 5-1
5.3 Contract Laboratory Quality Assurance Procedures 5-1
5.4 Test Program Personnel 5-2
5.5 Field Activities 5-3
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TABLES and FIGURES
Tables Page
S-l Summary of Chromium Removal Efficiencies iii
2.1 Average Operating Parameters Monitored
During Each Mass Emissions Test Run 2-6
2.2 Total Ampere-Hours Supplied to Plating
Tanks During Mass Emission Test Runs 2-7
3.1 Summary of Stack Gas Conditions 3-3
3.2 Comparison of Emission Sample Analysis
Results For Chromium-VI Using
Colorimetry and ICPCR Techniques 3-5
3.3 Analytical Results of Chromium-VI
Mass Emission Testing 3-6
3.4 Analytical Results of Total Chromium
Mass Emission Testing 3-7
3.5 Analysis of Plating Tank Solutions, MPME
Water and Blank Samples 3-9
3.6 Summary of the Mesh Pad Mist Eliminator
Chromium Removal Efficiencies 3-11
3.7 Removal Efficiency and Percent Penetration
of Chromium Through the
Mesh Pad Mist Eliminator 3-12
***********************
Jlgures
2.1 Schematic of Ventilation and Control System
for Chromium Plating Tanks at Precision
Engineering, Inc 2-3
4.1 Inlet No. 1 Traverse Point Locations 4-4
4.2 Inlet No. 2 Traverse Point Locations 4-5
4.3 Outlet Traverse Point Locations 4-6
4.4 Schematic of the Modified U.S. EPA
Method 13-B Sampling Train 4-9
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Appendices Page
A Computer Printout of Field Data A-l - A-37
B Field Data Sheets B-l - B-40
C Sampling Sheets and Summary of Results
(AST and U.S. EPA) C-l - C-17
D Laboratory Analysis Reports and
Chain of Custody Forms D-l - D-8
E On-Site Colorimetric Analysis
For Hexavalent Chromium E-l - E-12
F Sample Calculations F-l - F-8
G Draft Method - Determination of
Hexavalent Chromium Emissions from
Decorative and Hard Chrome Electroplating G-l - G-9
H Ampere-Hour Calculations H-l - H-26
I Laboratory Analysis Procedure Method
of Determination of Cr-VI in Alkaline Solution I-1 -1-3
J Equipment Calibration Data J-l - J-9
K Determination of Total Chromium and
Hexavalent Chromium Emissions from
Stationary Sources (CARB425) K-l - K-22
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EXECUTIVE SUMMARY
The objective of this project was to evaluate the chromium removal efficiency of the mesh pad
mist eliminator (MPME) system at Precision Engineering, Inc., in Seattle, Washington. This
objective was achieved by concurrently measuring hexavalent chromium (Cr-VI) and total
chromium (Cr-T) mass emissions at the inlets and outlet of a mesh pad mist eliminator (MPME)
using a modification of U.S. EPA Method 13-B.
During the field work, Precision Engineering, Inc. operated three of its six plating tanks.
Plating Tanks 1, 2 and 7 were being used to chrome plate pieces of industrial equipment. The
hood exhaust ducting from tanks 1 and 2 were combined in a common duct and formed one leg
of the inlet (Inlet No. 1) to the MPME. Tank 7 was ducted separately, forming the second leg
(Inlet No. 2) of the inlet to the MPME. The MPME used for controlling chromium mass
emissions was located on the roof of the plant shop and consisted of a set of chevron-blades
followed by a series of three graded mesh pads.
Field testing was conducted during the week of December 16, 1991. Sampling was performed
at the two inlets (Inlet No. 1 from Tanks 1 and 2 and Inlet No. 2 from Tank 7), and at the outlet
of the mesh pad mist eliminator (MPME) under its normal operating conditions for the plating
processes. Three separate isokinetic test runs were conducted during field testing. Sampling
times of 240 or 360 minutes assured collection of adequate quantities of chromium for
subsequent chemical analysis. In addition, grab samples of MPME water and plating bath
solutions were also obtained during each of the Method 13-B test runs for Cr-VI and Cr-T
analyses.
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Upon completion of each test run, the mass emission samples were recovered in the field,
labeled, and stored in a cooler. Each sample was analyzed on-site for Cr-VI using the
diphenylcarbazide colorimetric method (see Appendix E). Upon completion of field testing, all
samples were packed in a cooler and transported to Research Triangle Institute Laboratory
(RTIL), Research Triangle Park, North Carolina. RTIL performed analysis for Cr-VI using lon-
Chromatography with a Post Column Reactor (ICPCR) and Cr-T using Inductively Coupled
Plasma (ICP). Plating tank solution and MPME water samples were also analyzed for Cr-VI
and Cr-T at RTIL.
This project work has provided an opportunity to assess the accuracy of the analytical results
which form the basis to measure control device efficiencies. Field samples were analyzed for
Cr-VI using the diphenylcarbazide colorimetric method on-site and later the same samples were
analyzed off-site with ICPCR. The analytical data obtained were compared and indicate,
colorimetric and ICPCR methods gave overall similar results (see Section 3).
Table S-l summarizes the chromium removal efficiencies for the mesh pad mist eliminator
(MPME) system. Based upon the measurements performed during this project, the MPME has
an average chromium removal efficiency of 96.0%. The average total chromium (Cr-T)
concentration at Inlets No. 1 and No. 2 combined was 0.4970 mg/m3. The total chromium
emission concentration at the outlet averaged 0.0108 mg/m3. The average Cr-T mass emission
rate from Inlets No. 1 and No. 2 combined was 1.50 x 10~2 Ib/hr and for outlet average was 5.75
x 10^* Ib/hr. The average hexavalent chromium (Cr-VI) concentration at Inlets No. 1 and No.
2 combined was 0.4717 mg/m3 and for the outlet 0.0103 mg/m3. These averages translate into
Cr-VI mass emission rates of 1.430 x Itf2 Ib/hr and 5.48 x 1Q4 Ib/hr for the MPME inlets and
the outlet respectively.
11
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TABLE S-l
SUMMARY OF CHROMIUM* REMOVAL EFFICIENCIES
Run No. 1
Inlet**
Outlet
Mass Emission Rate
(Ib/hr)
1.32x lO'2
6.75 x KT*
Removal Efficiency
94.9
Run No. 2
Inlet**
Outlet
1.25 x lO'2
5.53 x 10"*
95.6
Run No. 3
Inlet**
Outlet
1.93x lO'2
4.97 x 10"
97.4
AVERAGE REMOVAL EFFICIENCY
96.0
* Expressed as Total Chromium (Cr-T)
** Represents Sum of Inlet No. 1 and Inlet No. 2
in
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Section 1
INTRODUCTION
The objective of this project was to evaluate the chromium removal performance of the mesh
pad mist eliminator (MPME) system at Precision Engineering, Inc., in Seattle, Washington.
Chromium emission concentrations were measured at the two inlets (Inlet No. 1 and Inlet No.
2) and the outlet of the MPME to determine the efficiency of the system for chromium removal.
Testing was conducted during the week of December 16, 1991. Emission samples were
collected using a modification of U.S. EPA Method 13-B. This method is briefly described in
Section 4 of this report. The emission samples were collected simultaneously from Inlets No.
1 and No. 2 and from the Outlet of the MPME under normal operating conditions. The
sampling locations are identified in Figure 2-1. MPME water samples and plating tank solution
samples were also collected under the normal operating conditions of the MPME and plating
processes.
Samples were analyzed on-site, using the diphenylcarbazide method, for hexavalent chromium.
The plating tank solution samples were analyzed off-site. After the field activities were
completed, the samples were shipped to Research Triangle Institute Laboratory (RTIL) for
chromium analyses. RTIL is located in Research Triangle Park, North Carolina. The Inlet and
Outlet samples were analyzed at RTIL for total chromium using Inductively Coupled Plasma
emission spectrometry (ICP) and for hexavalent chromium using lon-Chromatography with a
Post Column Reactor (ICPCR). MPME water samples and plating tank solution samples were
analyzed using ICPCR and ICP. The analytical techniques employed in this test program are
described in Section 4 of this report.
1-1
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The primary organizations involved in this test program were Advanced Systems Technology,
Inc. (AST), Precision Engineering, Inc. (PEI), Midwest Research Institute (MRI) and the U.S.
EPA, Emission Measurement Branch (EMB).
1-2
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Section 2
PROCESS OPERATION
2.1 Process Description
Precision Engineering is a medium-size job shop that performs hard chromium plating of
industrial rolls, hydraulic cylinders and miscellaneous small parts. The plating shop has six hard
chromium plating tanks. The plating shop normally operates 24 hours per day, five days per
week.
During this source test, tank Nos. 1, 2 and 7 were tested. Plating tank Nos. 1 and 2 are
2.0-meters (m) (6.5-feet) [ft]) long, 1.3-m (4.2-ft) wide, and 3.7m (12.0 ft) deep and hold
approximately 9,280 liters (L) (2,450 gallons [gal]) of plating solution. Plating tank No. 7 is
1.2-m (4.0-ft) long, 1.8-m (5.9-ft) wide and 5.5-m (18.0-ft) deep and holds approximately
11,830 L (3,120 gal) of plating solution. The plating solution contains chromic acid at a
concentration of about 250 grams per liter (g/L) (33 ounces per gallon [oz/gal]) of water.
Sulfuric acid is used as a catalyst at a bath concentration of 2.5 g/L (0.33 oz/gal). The
temperature of the plating solution is maintained at approximately 60°C (140°F).
The three plating tanks are divided into two cells and each cell is equipped with a rectifier to
to control the current flow. Current ratings per cell are 5,000 amperes, 3,000 amperes, and
10,000 amperes for tanks Nos. 1, 2 and 7, respectively. Each rectifier is also equipped with
ampere-hour meters that measure the amount of current supplied to the plating tanks over time.
All of the plating tanks are serviced by overhead hoists that are used to transfer parts in and out
of the tanks. Heating and cooling systems are located in each tank to maintain uniform solution
2-1
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temperature. In addition, each tank is equipped with an air agitation system to aid in
maintaining uniform bath concentration and temperature.
2.2 Air Pollution Control Device
A schematic of the ventilation and control system on the plating tanks is shown in Figure 2-1.
The mesh pad mist eliminator system was manufactured by KCH Services, Inc., in Forest City,
North Carolina. The system was installed during 1991 by plant personnel. Each tank is
equipped with a double-sided ventilation hood. Moisture extractors are located in the hood
uptakes to remove large chromic acid mist droplets prior to the mist eliminator. The purpose
of the moisture extractors is to reduce the plugging tendency of the mist eliminator by reducing
the inlet loading to the device. The takeoffs from tank Nos. 1 and 2 are ducted together and
form one inlet leg to the mist eliminator, while tank No. 7 is ducted separately and forms a
second leg to the mist eliminator. The ventilation system is rated at 470 cubic meters per minute
(16,500 cubic feet per minute). The pressure drop across the mist eliminator is 1.7 kiloPascals
(7 inches in water column).
The mist eliminator is installed on the roof of the plating shop and consists of a set of chevron-
blades followed by a series of three mesh pads. The mist eliminator is designed to remove
chromic acid mist in stages depending upon the particle size. The larger droplets (particles
greater than 10 microns), which comprise the majority of the emissions, are removed by the
moisture extractor located above tanks 1, 2 and 7 but before the mist eliminator and also by the
chevron-blade stage of the MPME. The first mesh pad is designed to remove smaller particles
(particles between 5 and 10 microns). The first mesh pad is composed of multiple layers of
mesh pad material, and each layer is woven from fibers with diameters of 0.09 centimeter (cm)
(37 thousandths of an inch [mils]. The second mesh pad (the composite mesh pad) is designed
2-2
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HIST ELtMfNATOfTK
'J.
f
»'»^. *~€t ft |
/"~ •«-»-u»«*».i*£vj
Jil3~
i
i
&•
•« era
TAM 1 " TANK 2
CA;
T)
^
vi>
®
c\
- SAMPLING LOCATION A AT INLET 1
- SAMPLING LOCATION 3_ AT INLET 2
- SAMPLING LOCATION C AT OUTLET
- SAMPLING LOCATION _0 TANK 1
- SAMPLING LOCATION £ TANK 2
- SAMPLING LOCATION £ TANK 7
- SAMPLING LOCATION G HASHDOWN WATE?.
lANK 7
Figure 2.1. Schematic of Ventilation and Control System for Chromium Plating
Tanks at Precision Engineering, Inc.
2-3
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such that the material layers in the center of the pad are composed of extremely small -diameter
fibers (0.02 cm [8 mils]). The smaller the fiber diameter, the more dense the material layer.
The material layers on either side of the center are composed of progressively larger diameter
fibers (0.04 to 0.09 cm [16 to 37 mils]). As the gas stream flows through the composite pad,
the small particles that escape the first mesh pad (particles below 5 microns) impinge on the
composite pad and coalesce into larger droplets. These enlarged particles are then removed in
the backside of the composite pad or in the backup mesh pad located downstream of the
composite pad. The third pad or backup mesh pad is composed of layers of material with a fiber
diameter of 0.09 cm (37 mils). The thickness of each pad is 15.7 cm (6.2 inches [in.]), 9.7 cm
(3.8 in.), and 18.3 cm (7.2 in.) for the first, second, and third pads, respectively.
Prior to each mesh pad is a series of spray nozzles that are used to wash down the pads and
remove any chromium that has built up on the pads. The pressure drop across each mesh pad
is monitored to determine the amount of chromium buildup on the pad. An increase in pressure
drop above the normal operating range for a given pad indicates that the pad needs to be washed
down. Spray nozzles are also located in the chevron-blade section to allow periodic washing of
the blades.
2.3 Process Conditions During Testing
Three mass emission test runs were conducted at the two inlet locations and the outlet of the mist
eliminator to characterize the performance of a mesh-pad mist eliminator system that
incorporated the use of a composite mesh pad. Each test run was 4 or 6 hours in duration. All
of the test runs were interrupted briefly to change test ports. No other interruptions occurred
during sampling.
2-4
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Sampling of Inlet No. 1 and Inlet No. 2 was performed at distances of 18 feet from the nearest
downstream disturbance and 4 feet from the nearest upstream disturbance (mist eliminator).
Sampling of the Outlet was performed at a distance of 60 inches from the nearest downstream
disturbance (outlet base) and 35 inches from the nearest upstream disturbance (top of exhaust
stack).
Process operating parameters monitored and recorded during each test run included the voltage,
current, ampere-hours, and the plating solution temperature for each plating tank. A description
(dimensions and surface areas) of each part plated also was recorded for each test run. Process
data sheets documenting the process and control device operating parameters during mass
emission testing are presented in Appendix H. Data on the average operating parameters
recorded during the mass emission test runs are presented in Table 2-1. The total amount of
current supplied to the tanks during each test run is calculated in terms of ampere-hours and is
included in Appendix H.
A tabular summary of the total current values is presented in Table 2-2. As noted previously,
the ampere-hours supplied during testing were monitored and recorded from the ampere-hour
meters on each rectifier. However, the sum of the ampere-hours for each rectifier will not
match the ampere-hours calculated in Appendix H because of the difference between the actual
sampling time and the time required for testing. These time periods are not equal because of
the time required to change test ports. Therefore, the ampere-hours measured by the ampere-
hour meters will be slightly higher than the actual ampere-hours calculated in Appendix H.
2-5
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Table 2.1. AVERAGE OPERATING PARAMETERS
MONITORED DURING EACH MASS EMISSIONS TEST RUN
Test
Run No.
1
2
.3
Tank
No.
1A
IB
2A
2B
7A
7B
1A
IB
2A
2B
7A
7B
1A
IB
2A
2B
7A
7B
Operating
Voltage,
Volts
7.0
7.0
7.6
7.6
~
8.0
6.4
6.3
7.2
7.4
6.6
6.4
6.4
6.4
7.7
7.8
6.0
7.3
Operating
Current,
Amperes
4,300
3,700
2,300
1,400
--
7,000
3,600
3,400
1,700
1,850
1,300
2,000
2,970
2,800
2,000
1,700
1,000
7,200
Operating
Temperature
oF
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
2-6
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Table 2.2. TOTAL AMPERE-HOURS SUPPLIED TO
PLATING TANKS DURING MASS EMISSION TEST RUNS
TOTAL CURRENT, AMPERE-HOURS
Test Run No.
1
2
3
Inlet No. 1"
67,020
42,000
37,975
Inlet No. 2b
42,025
28,690
32,750
Outlet
109,045
70,690
70,725
a Total current for Tanks 1 and 2 combined
b Total current for Tank 7
2-7
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Composite samples were taken from each plating tank to determine the chromic acid
concentration of the plating solutions during each mass emission test run. The data obtained are
reported in Section 3 of this report.
MPME operating parameters monitored during each test run consisted of the pressure drop
across the unit, and the overall system pressure drop. The Magnahelic gauges are located
downstairs in the plating shop; therefore, the pressure drop readings on the Magnahelic gauges
are not indicative of the actual pressure drop but are approximate values because of the pressure
losses in the tubing that connect the Magnahelic gauges to the mist eliminator. However, the
important factor in monitoring the pressure drop is any decrease or increase from the normal
operating range. An increase in pressure drop over its normal range indicates that the pad is
beginning to plug, and a decrease in pressure drop indicates that the gas stream is bypassing the
pad. The pressure drop readings recorded across each pad and the overall unit were consistent
for all test runs.
2-8
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Section 3
SUMMARY OF SAMPLE COLLECTION,
EMISSION CALCULATIONS AND RESULTS
3.1 Sample Collection
Emission samples were collected using a modification of U.S. EPA Method 13-B. The samples
were collected simultaneously from Inlets No. 1 and No. 2 and from the Outlet of the MPME
under normal operating conditions. Three tests were conducted at each sampling location.
Sampling times of 4 or 6 hours per test run were used to ensure that adequate quantities of
chromium were collected for subsequent chemical analysis.
Grab samples from the plating tank solutions (Tanks 1, 2 and 7) and the MPME water were also
collected during each sampling run. These samples were obtained at the beginning, middle and
at the end of each Method 13-B test run.
3.2 Stack Gas Parameters
Stack gas parameters, at each sampling location, are shown in Table 3-1. At Inlet No. 1, the
stack gas velocity averaged 50.66 feet per second (fps), the average stack temperature was 78°F
and the average moisture content was 1.11%. The volumetric flow rates at Inlet No. 1 were
9,548 actual cubic feet per minute (acfm) and 9,180 dry standard cubic feet per minute (dscfm).
At Inlet No. 2, the stack gas velocity averaged 50.34 fps, the average stack temperature was
77°F and the average moisture content was 0.75%. The volumetric flow rates at Inlet No. 2
were 5,337 acfm and 5,159 dscfm.
3-1
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At the Outlet, the stack gas velocities averaged 50.11 fps, the average stack temperature was
85 °F and the average moisture content was 0.98%. The average volumetric flow rates at the
Outlet were 14,758 acfm and 14,241 dscfm.
The stack gas at all sampling locations was essentially ambient air and thus was assigned a dry
molecular weight of 28.95 Ib/lb-mole. Variation in isokinetic sampling rates were within
allowable limits for all sampling runs of Method 13-B except Run 2 of Inlet 2 which had an
isokinetic rate of 88.81%.
The evaluation of particle size, from previous test runs, indicate that more than 85% of the
particles emitted from a controlled electroplating process are less than 2.5 microns in diameter.
Particles less than 2.5 microns behave like a gas rather than a paniculate. In gaseous sampling
the isokinetic sampling rate is not considered to be significant. Therefore, no adjustments were
made to the data and the results are acceptable.
3.3 Emission Calculations and Discussion of Results
This subsection of the report provides the following information: 1) Cr-VI results from
colorimetry and ICPCR analyses; 2) Cr-T results from ICP analysis; 3) Cr-VI and Cr-T
concentrations in the plating tank solutions, MPME water and sampling train blank samples;
4) computerized spreadsheet calculations of emission concentrations and mass emission rates;
5) MPME removal efficiencies; and 6) MPME penetration.
3-2
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Table 3.1 SUMMARY OF STACK GAS CONDITIONS
Inlet No.l
Run No.
1
2
3
Average
Velocity
fps-
50.77
48.53
52.66
50.66
Stack
Temp. °F
96
69
70
78
Flow Rate
acfmb
9,570
9,148
9,927
9,548
dscfmc
8,901
8,830
9,810
9,180
Moisture
%
0.98
1.14
1.21
1.11
%
Isokinetic
Rate
101.52
98.99
93.32
97.94
Inlet No. 2
Run No.
1
2
3
Average
Velocity
fps"
52.14
52.02
46.85
50.34
Stack
Temp. °F
93
70
68
77
Flow Rate
acfmb
5,528
5,516
4,968
5,337
dscfme
5,183
5,350
4,943
5,159
Moisture
%
0.67
0.65
0.94
0.75
%
Isokinetic
Rate
103.02
88.81
98.37
96.73
Outlet
Run No.
1
2
3
Average
Velocity
fps"
50.88
49.03
50.41
50.11
Stack
Temp. °F
111
72
72
85
Flow Rate
acfmb
14,986
14,442
14,847
14,758
dscfm0
13,776
14,065
14,882
14,241
Moisture
%
0.97
1.08
0.90
0.98
%
Isokinetic
Rate
109.24
99.68
99.48
102.80
Feet per second
b Actual cubic feet per minute
c Dry standard cubic feet per minute at 68 °F and 29.92" Hg
3-3
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3.3.1 Cr-VI Results From Colorimetrv and ICPCR Analyses
Table 3.2 lists Cr-VI results obtained from two analytical techniques namely: 1) colorimetry
using diphenylcarbazide; and 2) ICPCR. The colorimetric technique, used in the field to
determine Cr-VI, provided a rapid analysis of chromium concentrations. The results were not
used in the emission calculations in this report and are provided in Appendix E for information
only. RTIL's analytical results for total chromium (Cr-T) and hexavalent chromium
(Cr-VI) were used to make emission calculations in this report.
Table 3.3 provides analytical results of Cr-VI mass emission testing at the Precision
Engineering, Inc. plant. The samples were analyzed using lon-Chromatography with a Post
Column Reactor (ICPCR). RTIL's analytical data report is provided in Appendix D. The
average concentration of Inlets No. 1 and No. 2 combined was 0.4717 mg/m3 of Cr-VI and the
outlet average concentration was 0.0103 mg/m3 . These averages translate into Cr-VI mass
emission rates of 1.43 x 10"2 Ib/hr and 5.48 x 10"* Ib/hr for the inlets and the outlet respectively.
3.3.2 Total Chromium Results From ICP Analysis
Presented in Table 3.4 are the total chromium (Cr-T) emission results. RTIL's analytical data
report is provided in Appendix D. Table 3.4 shows an average Cr-T emission concentration of
0.497 mg/m3 at Inlets No. 1 and No. 2 combined. The Cr-T emission concentration at the outlet
averaged 0.0108 mg/m3. The average Cr-T mass emission rate from Inlets No. 1 and No. 2
combined was 1.50 x 10"2 Ib/hr and the outlet average emission rate was 5.75 x 104 Ib/hr.
3-4
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Table 3.2. COMPARISON OF EMISSION SAMPLE
ANALYSIS RESULTS' FOR CHROMIUM-VI USING
COLORIMETRY" AND ICPCRC TECHNIQUES
Inlet No. 1
Test Run No.
Run No. 1
Run No. 2
Run No. 3
Average
Sampling Time
(min)
360
240
240
Total Cr-VI (/ig)
Colorimetryb
2,862
743
848
1,484
ICPCR£
2,889
1,774
2,891
2,518
Inlet No. 2
Run No. 1
Run No. 2
Run No. 3
Average
360
240
240
1,517
808
779
1,035
1,589
770
813
1,057
Outlet
Run No. 1
Run No. 2
Run No. 3
360
240
240
123
37.8
50.3
Average 70.4
146
60.6
53.5
86.7
1 Results are expressed as total microgram of Chromium-VI
b Colormetric quantification on-site using diphenylcarbazide organic analytical reagent
c lon-chromatography with a post column reactor.
3-5
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Table 3.3. ANALYTICAL' RESULTS OF CHROMIUM-VI
MASS EMISSION TESTING
Inlets"
Test
Run No.
1
2
3
Average
Total Cr-VI
0*g)c
4,478
2,544
3,704
3,575
Emission
Concentration
(mg/m3)1
0.4465
0.4045
0.5640
0.4717
Mass
Emission Rate
(lb/hr)c
1.276x 10-2
1.175x 10-2
1.838 x 10-2
1.430 x 10 2
Mass
Emission
Rate
(kg/hr)c
5.79 x lO'3
5.33 x 10-3
8.33 x lO'3
6.48 x 10 3
Outlet
Test
Run No.
1
2
3
Average
Total Cr-VI
(Mg)°
146
60.6
53.5
86.7
Emission
Concentration
(mg/m3) c
0.0139
0.0093
0.0078
0.0103
Mass
Emission
Rate
(lb/hr)c
7.19x 10"
4.91 x 10"
4.34 x 10"
5.48 x 10"
Mass
Emission
Rate
(kg/hr)£
3.26 x 10"
2.22 x 10"
1.97x 10"
2.48 x 10"
a Analysis method, lon-Chromatography with Post Column Reactor.
b The control device has two inlets (Inlet No. 1 and Inlet No.2).
0 Sum of Cr-VI emissions from Inlet No. 1 and Inlet No.2.
3-6
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Table 3.4. ANALYTICAL1 RESULTS OF TOTAL CHROMIUM
MASS EMISSION TESTING
Inletsb
Test
Run No.
1
2
3
Average
Cr-T Otg)c
4,602
2,728
3,921
3,750
Emission
Concentration
(mg/m3)c
0.4592
0.4341
0.5976
0.4970
Mass Emission
Rate
(lb/hr)e
1.32x 10-2
1.25 x 10-2
1.93 x ID'2
1.50 x 10 2
Mass Emission
Rate
(kg/hr)c
5.991 x lO'3
5.656 x 10'3
8.741 x 10'3
6.796 x 103
Outlet
Test
Run No.
1
2
3
Average
Cr-T (/ig)c
137.0
68.3
61.3
88.9
Emission
Concentration
(mg/m3)£
0.0131
0.0105
0.0089
0.0108
Mass Emission
Rate
(lb/hr)c
6.75 x 10-4
5.53 x 10^
4.97 x IQi4
5.75 x 10-4
Mass Emission
Rate
(kg/hr)c
3.06 x 10-4
2.51 x 10-4
2.26 x 10-4
2.61 x 10-4
• Analysis method, Inductively Coupled Plasma (ICP)
b The control device has two inlets (Inlet No. 1 and Inlet No. 2)
c Sum of total chromium emissions from Inlet No. 1 and Inlet No. 2
3-7
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3.3.3 Concentrations In Plating Tank Solution. MPME Water and Train Blank Samples
Cr-VI and Cr-T concentrations in the plating tank solution, MPME water and train blank
samples were determined by RTIL using ICPCR and ICP. The sample concentrations are
presented in Table 3.5. The concentrations of chromium remained essentially constant
throughout the testing period.
3.3.4 Computerized Spreadsheet Calculations
A computerized spreadsheet, provided by Mr. Frank Clay (U.S. EPA, Task Manager), was used
to calculate the emission concentrations and mass emission rates in this report. Manual
calculations were made by AST personnel to verify that the computer results were accurate. The
computer printouts are provided in Appendix A. Appendix F presents the equations used to
make these manual verifications.
3.3.5 Removal Efficiency of The Mesh Pad Mist Eliminator
Chromium removal efficiencies for the MPME system were determined by simultaneously
sampling the two inlets and outlet of the MPME. The mass emission rates were used to
calculate removal efficiencies. Removal efficiency is calculated using the equation below.
RE = -^-2 x 100
c,
Where:
RE = % Removal Efficiency
Ci = ]£ of mass emission rates at Inlets 1 and 2, Ib/hr
C0 = Mass emission rate at the outlet, Ib/hr
3-8
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Table 3.5. ANALYSIS OF PLATING TANK SOLUTIONS,
MPME WATER AND BLANK SAMPLES
SAMPLES*
Tank 1 Run No. 1
Tank 1 Run No. 2
Tank 1 Run No. 3
Tank 2 Run No. 1
Tank 2 Run No. 2
Tank 2 Run No. 3
Tank 7 Run No. 1
Tank 7 Run No. 2
Tank 7 Run No. 3
Sampling Train
Blank0
MJ Outlet Run No. 1
MJ Outlet Run No. 2
MJ Outlet Run No. 3
Cr-VP Oig/ml)
1.22x 10+5
8.59 x 10+4
l.OSx 10+5
1.15x 10+5
1.22x 10+5
1.14x 10+s
1.23 x 10+5
1.23 x 10+5
1.20x 10+5
7.37 x 10"3
7.59 x lO'2 (6.4 x 10-2")
7.43 x 1C'2 (5.00 x 10-2**)
1.81 x 10-' (2.03 x 10-'")
Cr-Tb Otg/ml)
1.31 x 10+5
1.30x HT5
1.26x 10+5
1.27x 10+5
1.25x 10+5
1.24x 10+5
1.23x 10+5
1.26 x 10+s
1.25 x 10+s
3.20 x lO'2
2.69 x lO'1
2.86 x 10-1
6.00 x 10-3
* Liquid grab samples from tanks 1, 2, 7 and the MPME were collected at the beginning,
middle and end of each Method 13-B run. All samples are composites.
* ICPCR was used for analysis
b ICP was used for analysis
0 The Method 13-B sampling train was cleaned between test runs. The blank sample, is a
rinseate, was collected after cleaning the train components.
** In-field colorimetric analysis results for MPME water
3-9
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Mass emission rates are presented in Tables 3.3 and 3.4. The data in Tables 3.3 and 3.4
indicate that more than 95% of the mass emissions are of Cr-VI and less than 5% of the
emissions are of Cr-III.
3.3.6 Penetration of The Mesh Pad Mist Eliminator
Penetration can be used to evaluate the performance of a chromium emission control device such
as a MPME. Penetration is defined as the percentage of chromium that escapes or is not
collected by an emission control device. Percent penetration is calculated using the equation
below.
Percent Penetration= 100% - RE
Where:
RE = % Removal Efficiency
Often, the percent penetration results reveal more about the process conditions than the percent
efficiency results.
The calculated removal efficiencies are tabulated in Table 3.6. The average removal efficiency
for Cr-VI was 95.94%. The average removal efficiency for Cr-T was 95.96%. The removal
efficiencies for Cr-T and Cr-VI are essentially the same. As pointed out earlier, most of the
mass emissions are of Cr-VI (—95%). The percent penetration for each test run was also
calculated. Table 3.7 lists the results of the removal efficiency and the percent penetration
calculations. Table 3.7 shows that about 4% of the chromium emissions penetrated the mesh
pad mist eliminator.
3-10
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Table 3.6. SUMMARY OF THE MESH PAD MIST ELIMINATOR
CHROMIUM REMOVAL EFFICIENCIES
Analyte
Cr-VI
Cr-VI
Cr-VI
Average
Cr-T
Cr-T
Cr-T
Average
Analytical
Technique
Used
ICPCR
ICPCR
ICPCR
NA
ICP
ICP
ICP
NA
Test
Run
No.
1
2
3
NA
1
2
3
NA
Mass
Emission
Rates at
Inlets No. 1
and No. 2*
(Ib/hr)
1.276x lO'2
1.175x ID'2
1.838x lO'2
1.430 x 10 2
1.320x ID'2
1.247x ID'2
1.927x lO'2
1.498 x 10 2
Mass
Emission
Rate at
Outlet
(Ib/hr)
7.190x 10"
4.906 x 10"
4.340 x 10"
5.479 x 10"
6.747 x 10"
5.530 X 10"
4.972 x 10"
5.750 x 10"
Removal
Efficiency
(%)
94.37
95.82
97.64
95.94
94.89
95.57
97.42
95.96
* - Inlets 1 and 2 mass emission rates were combined.
NA - Not Applicable
3-11
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Table 3.7. REMOVAL EFFICIENCY AND PERCENT
PENETRATION* OF CHROMIUM THROUGH THE
MESH PAD MIST ELIMINATOR
Test Run No.
1
2
3
Average
% Removal Efficiency
Cr-VI
94.37
95.82
97.64
95.94
Cr-T
94.89
95.57
97.42
95.96
% Penetration
Cr-VI
5.63
4.18
2.36
4.06
Cr-T
5.11
4.43
2.58
4.04
* Percent Penetration = 100% - % Removal Efficiency
3-12
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Section 4
SAMPLING AND ANALYSIS METHODS
4.1 Types of Samples Collected and Sample Recovery Descriptions
Two types of samples were collected during field testing at the Precision Engineering, Inc. plant:
1) liquid grab samples; and 2) gaseous stack samples. A description for each sample type
collected is provided below.
4.1.1 Liquid Grab Samples
The plating tank solution and the mesh pad mist eliminator water samples were collected during
each sampling run, in pre-cleaned Mason jars. For example, one plating tank solution sample
consisted of three sample fractions collected in the same Mason jar. Each sample fraction was
collected at different periods (i.e., beginning, middle and end) of a test run. Nine (9) composite
plating tank solution samples were collected from plating tanks (1,2 and 7) and 3 composite
samples were collected from the mesh pad mist eliminator during this project. Each sample was
labeled with date, run number and sample location.
•4.1.2 Gaseous Stack Samples
Gaseous stack samples were collected from two inlet locations (Inlet No. 1 and Inlet No. 2) and
one Outlet location, using Method 13-B. Method 13-B stack samples were recovered
immediately after each test run. The contents of impingers 1 and 2 were measured for volume
increase and then transferred to a pre-weighed and pre-cleaned plastic bottle. The nozzle, probe
and glass tubing connecting the impingers were washed with 0. IN NaOH. These washings were
added to the same plastic bottle. Silica gel from the fourth impinger was weighed to determine
4-1
-------
weight gain from moisture absorption. The silica gel was then placed in a container, labeled and
stored in the cooler.
A sampling train blank sample was collected after each Method 13-B test run. This was
performed by thoroughly rinsing the inside of the sampling train components with a 0. IN NaOH
solution and then placing the rinseate into a container labeled "Sampling Train Blank." The
sampling train blank was stored in the cooler. Field blank samples were also prepared, labeled
and stored in the cooler.
4.1.3 Sampling Locations
Inlet No. 1
Inlet No. 1 was located on a straight run of 24-inch diameter duct work just before the mesh pad
mist eliminator. Sampling ports were cut at a location approximately 18 feet downstream and
4 feet upstream from the nearest disturbance. According to U.S. EPA Method 1 criteria, this
location required 12 traverse points, six along each of the two perpendicular diameters. Figure
4.1 shows Inlet No. 1 traverse point locations.
Inlet No. 2
Inlet No. 2 was located on a straight run of 18-inch diameter duct work just before the control
.device. Sampling ports were cut at a location approximately 18 feet downstream and 4 feet
upstream of the nearest disturbance. Twelve traverse points were also required at this location.
Figure 4.2 shows Inlet No. 2 traverse point locations.
4-2
-------
Outlet
The Outlet of the mesh pad mist eliminator was a 30-inch diameter stack. The total height of
the stack was about 95 inches. This total height included a 24-inch stack extension attached to
the stack during the test. A butterfly-type cap was installed to prevent extraneous materials from
entering into the stack. Sampling ports were cut at a location approximately 60 inches
downstream and 35 inches upstream of the nearest disturbance. Figure 4.3 shows the Outlet
traverse point locations. Twenty-four traverse points were required at this location; 12 along
each of the two perpendicular diameters. Figure 4.3 shows the Outlet traverse point locations.
Figures 4.1 through 4.3 show traverse point locations along one perpendicular diameter. The
total number of traverse points, in these figures, are obtained by multiplying the traverse point
locations shown by two.
4-3
-------
DIAMETER
24.0"
Figure 4.1. Inlet No. 1 Traverse Point Locations
4-4
-------
DIAMETER
18.0"
Figure 4.2. Inlet No. 2 Traverse Point Locations
4-5
-------
DIAMETER
30"
Figure 4.3. Outlet Traverse Point Locations
4-6
-------
4.2 Air Sampling Test Methods
The test methods used during this project were in accordance with U.S. EPA Methods 1, 2, 4
and a modification of Method 13-B. Method 13-B, designed for total fluoride emission testing
was used for the chromium paniculate collection. A brief description of each method used in
given below.
4.2.1 Traverse Points
U.S. EPA Method 1 "Sample and Velocity Traverses for Stationary Sources" was used to
determine the location of traverse points. Cyclonic flow checks were made prior to testing.
These checks indicated that cyclonic flow conditions did not exist at the sampling locations.
4.2.2 Stack Gas Velocity
U.S. EPA Method 2 "Determination of Stack Gas Velocity and Volumetric Flow Rate (Type "S"
Pilot Tube)" was used to measure the stack gas velocity and temperature at each test point.
Type K" thermocouples were affixed to type "S" pilot tubes having an assigned coefficient of
0.84. The velocity pressure was measured on an inclined manometer. The volumetric flow rate
was calculated from the stack gas velocity and the stack cross-sectional area. Since this was an
ambient source, a dry molecular weight of 28.95 Ib/lb-mole was used.
4.2.3 Stack Gas Moisture
U.S. EPA Method 4 "Determination of Moisture Content in Stack Gas" was used to determine
the stack gas moisture content. These moisture determinations were made during the modified
Method 13-B test runs.
4-7
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4.2.4 Modified Method 13-B Sampling Train
A modification of U.S. EPA Method 13-B "Determination of Total Fluoride Emission from
Stationary Sources" was used to collect chromium emission samples. The sampling train
consisted of a glass button-hook nozzle, an unheated "Pyrex" glass-lined probe and a series of
four impingers.
Isokinetic samples were collected during each test run. During sampling, stack gases were
pulled through the nozzle, past the probe and then through four impingers, where the chromium
was collected and retained. The contents and the configuration of the impingers are given
below.
1. The first impinger contained 100 ml of 0. IN NaOH.
2. The second impinger contained 100 ml of 0. IN NaOH.
3. The third impinger was empty.
4. The fourth impinger contained a weighted amount of silica gel (200 grams).
The remainder of the train consisted of a vacuum pump, dry gas meter, calibrated orifice and
related temperature and pressure measuring equipment. Figure 4.4 shows a Schematic of the
Modified U.S. EPA Method 13-B Sampling Train.
4.3 Sample Analysis Methods
The samples collected during the Modified 13-B testing were analyzed using one of three
analytical techniques. The techniques were: 1) Colorimetry; 2) Inductively Coupled Plasma
(ICP); and 3) lon-Chromatography with a Post Column Reactor (ICPRC). Each analytical
technique is briefly described below. ICP and ICPCR analyses were done by RTIL. The
colorimetric analyses for hexavalent chromium were performed by AST personnel in the field.
4-8
-------
CONTAINER I.D.
Impinger #\
Impinger #2
Impinger #3
Impinger #4
CONTAINER CONTENT
Modified Greenburg-Smith - 100 ml
ofO.lNNaOH
Standard Greenburg-smith - 100 ml
Modified Greenburg-Smith - Empty
Modified Greenburg-Smith 200 grams
of Silica Gel
mast
Figure 4.4. Schematic of the Modified U.S. EPA Method 13-B
Sampling Train
4-9
-------
4.3.1 Colorimetry
Colorimetry was used on-site to analyze samples (i.e., inlet, outlet, sample train blank and
MPME water) for Cr-VI. A known aliquot of the sample was made to react with a
diphenylcarbazide solution at a pH of 2.00± 0.5. Optimum color development requires 10
minutes. The intensity of the color is measured at 540 nm. The details of this procedure are
given in Appendices G and K.
4.3.2 Inductively Coupled Plasma (ICP)
ICP was used to determine total chromium in plating tank solution, MPME water, blank and
emission samples. ICP is a simple and fast technique used for analysis of major and minor trace
elements in samples of all kinds and matrices. It has a detection limit of one part per billion
(ppb) or less. Samples are aspirated into a high temperature argon plasma. The argon plasma
causes molecular breakdown, atomization and/or ionization and excitation of metals in solution.
The excited atoms release characteristic radiation which is detected by a photomultiplier tube
(PMT). The PMT produces an electrical current which is transformed into concentration values
by reference to a standard.
4.3.3 lon-Chromatographv With Post Column Reactor (ICPCR)
ICPCR was used to determine hexavalent chromium (Cr-VI) in the plating tank solution, MPME
water, blank and emission samples. Hexavalent chromium is chromatographed as CrO4'2 on an
ion column. After separation, the Cr-VI diphenylcarbazide complex is quantified by visible
spectrometry at 520 nm. ICPCR has a sub-part per billion detection limit. Typically, ICPCR
instrumentation consists of: 1) an ion column; 2) a visible spectrophotometer detector; and 3)
an integrator. Details of the ICPCR analytical technique are provided in Appendix I.
4-10
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Section 5
QUALITY ASSURANCE PROGRAM, TEST PROGRAM
PERSONNEL AND SUMMARY OF FIELD ACTIVITIES
5.1 Quality Assurance Program
AST's QA program consisted of the field-related procedural activities and contract laboratory
activities. A discussion of the QA activities is given below. The quality assurance activities
employed during this project were performed to assure the quality of the data collected.
5.2 Data Review Prior To Report Preparation
All field data were recorded on standard data sheets. The field data sheets are in Appendix B.
Field data were also recorded on sampling summary sheets. The sampling summary sheets are
in Appendix C. Upon returning to the office, AST personnel reduced the field data collected.
Afterwards, the results were summarized in a tabular format and reviewed for inconsistencies
or other incidences that may indicate errors (data entries or calculations). Prior to reviewing
the summary, spot checks of the field data reductions were made to ensure that all raw data were
correct and complete.
5.3 Contract Laboratory Quality Assurance Procedures
The contract laboratory's QA program was established to ensure that its personnel produce valid
analytical results. This goal is accomplished by regularly monitoring the reliability (i.e.,
precision, accuracy, reproducibility) of the reported results.
5-1
-------
Quality assurance activities taken to ensure high quality analytical results include the following:
• Reagent blank samples were prepared and analyzed
• QC check standards were analyzed at the beginning of a test run to verify a standard
curve
Spiked blanks were prepared and analyzed to assure there were no interferences
Duplicate samples were prepared and analyzed to assure the analytical precision
• Instrumentation performance was regularly monitored and repairs were made when
required
5.4 Test Program Personnel
The personnel involved in the completion of this test program, their titles and their job
affiliations are listed below.
Frank Clay - Task Manager, U.S. EPA
Tom Yaroch - Project Manager, AST
James Parker - Technician, AST
Michelle Knox - Laboratory Analyst, AST
Ron Kirkland - Meter Reader, AST
Jim Dini - Meter Reader, AST
Chuck Hames - Meter Reader, AST
5-2
-------
5.5 Field Activities
The following is a summary of the field activities:
12/16/91 Traveled to Seattle, Washington, inventoried equipment, prepared site
12/17/91 Conducted one, six-hour measurement run at each site, recovered and analyzed
emission samples
12/18/91 Conducted one, four-hour measurement run at each site, recovered and
analyzed emission samples
12/19/91 Conducted one, four-hour measurement run at each site, recovered and
analyzed emission samples; restored site, packed and shipped equipment
12/20/91 Traveled to Atlanta, Georgia
5-3
-------
April 29, 1993
NOTE:
Attached is an addendum to the source test at the
electroplating facility in Seattle, Washington.
Frank R. Clay
'-«.'. ^ • > *-
-------
ADDENDUM FOR THE U.S. ENVIRONMENTAL PROTECTION AGENCY TEST
REPORT FOR THE DECEMBER 1991 SOURCE TEST AT THE PRECISION
ENGINEERING, INC. ELECTROPLATING FACILITY IN SEATTLE, WASHINGTON
At the request of Midwest Research Institute, this addendum
has been prepared for the Precision Engineering Test Report. The
changes are minor and correct field data and calculations found in
the report.
After the first run of the source test, it was discovered that
the thermocouple indicator readings used to determine inlet and
outlet stack temperatures were biased about 20 degrees F too high.
For the remaining runs, dial thermometers were used for stack
temperature readings.
In the original version of the test report stack temperatures
obtained from the thermocouple were used in the data reduction for
Run 1. For this addendum, the average stack temperatures from Runs
2 and 3 are used in the reduction of the data from Run 1. Changes
were made throughout Chapter 3 wherever the corrected temperatures
had an effect.
This addendum is composed of two parts: (1) revisions to
Chapter 3 and (2) computer print outs. The addendum for Chapter
3 contains the entire chapter and completely replaces the original
Chapter 3. The new computer print outs replace the original print
outs for Run 1 data from both the inlet and the outlet locations.
For reports with appendices, replace both Chapter 3 and the
computer print out sheets; for reports without appendices only
Chapter 3 need be replaced.
-------
Section 3
SUMMARY OF SAMPLE COLLECTION,
EMISSION CALCULATIONS AND RESULTS
3.1 Sample Collection
Emission samples were collected using a modification of U.S. EPA Method 13-B. The samples
were collected simultaneously from Inlets No. 1 and No. 2 and from the Outlet of the MPME
under normal operating conditions. Three tests were conducted at each sampling location.
Sampling times of 4 or 6 hours per test run were used to ensure that adequate quantities of
chromium were collected for subsequent chemical analysis.
Grab samples from the plating tank solutions (Tanks 1, 2 and 7) and the MPME water were also
collected during each sampling run. These samples were obtained at the beginning, middle and
at the end of each Method 13-B test run.
3.2 Stack Gas Parameters
Stack gas parameters, at each sampling location, are shown in Table 3-1. At Inlet No. 1, the
stack gas velocity averaged48.92feet per second (fps), the average stack temperature was 70°F
and the average moisture content was 1.11%. The volumetric flow rates at Inlet No. 1 were
9473 actual cubic feet per minute (acfm) and 9254 dry standard cubic feet per minute (dscfm).
At Inlet No. 2, the stack gas velocity averaged49.96fps, the average stack temperature was
69°F and the average moisture content was 0.75%. The volumetric flow rates at Inlet No. 2
were 52.97 acfm and 5198 dscfm.
3-1
-------
At the Outlet, the stack gas velocities averaged49.53fps, the average stacK temperature was
72°F and the average moisture content was 0.98%. The average volumetric flow rates at the
Outlet were 14588 acfm and 14406 dscfm.
The stack gas at all sampling locations was essentially ambient air and thus was assigned a dry
molecular weight of 28.95 Ib/lb-mole. Variation in isokinetic sampling rates were within
allowable limits for all sampling runs of Method 13-B except Run 2 of Inlet 2 which had an
isokinetic rate of 88.81%.
The evaluation of particle size, from previous test runs, indicate that more than 85 % of the
particles emitted from a controlled electroplating process are less than 2.5 microns in diameter.
Particles less than 2.5 microns behave like a gas rather than a paniculate. In gaseous sampling
the isokinetic sampling rate is not considered to be significant. Therefore, no adjustments were
made to the data and the results are acceptable.
3.3 Emission Calculations and Discussion of Results
This subsection of the report provides the following information: 1) Cr-VI results from
colorimetry and ICPCR analyses; 2) Cr-T results from ICP analysis; 3) Cr-VI and Cr-T
concentrations in the plating tank solutions, MPME water and sampling train blank samples;
4) computerized spreadsheet calculations of emission concentrations and mass emission rates;
5) MPME removal efficiencies; and 6) MPME penetration.
3-2
-------
Table 3.1 SUMMARY OF STACK GAS CONDITIONS
Inlet No.l
Run No.
1
2
3
Average
Velocity
fps"
45.58
48.53
~ 52.66
48.92
Stack
Temp. °F
70
69
70
70
Flow Rate
acfmb
9345
9,148
9,927
9473
dscfm'
9122
8,830
9,810
9254
Moisture
%
0.98
1.14
1.21
1.11
%
Isokinetic
Rate
99.05
98.99
93.32
97.12
Inlet No. 2
Run No.
1
2
3
Average .
Velocity
fps-
51.01
52.02
46.85
49.96
Stack
Temp. °F
69
70
68
69
Flow Rate
acfmb
5408
5,516
4,968
. 5297
dscfme
5301
5,350
4,943
5198
Moisture
%
0.67
0.65
0.94
0.75
%
Isokinetic
Rate
100.72
88.81
98.37
95.97
T)utlet
Run No.
1
2
3
Average
Velocity
fps"
49.15
49.03
50.41
49.53
Stack
Temp. °F
. 72
72
72
72
Flow Rate
acfmb
14474
14,442
14,847
14588
dscfmc
14272
14,065
14,882
14406
Moisture
%
0.97
1.08
0.90
0.98
%
Isokinetic
Rate
105.45
99.68
99.48
101.54
Feet per second
b Actual cubic feet per minute
c Dry standard cubic feet per minute at 68 °F and 29.92" Hg
3-3
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3.3.1 Cr—VI Results From Colorimefary and ICPCR Analyses
Table 3.2 list Cr-VI results obtained from two analytical
techniques, namely: 1) colorimetry using diphenylcarbazide; and 2)
ICPCR. The colorimetric technique , used in the field to determine
Cr-VI, provided a rapid analysis of chromium concentrations. The
results were not used in the emission calculations in this report
and are provided in Appendix E for information only. RTIS's
analytical results for total chronium (Cr-T) and hexavalent
chromium '(Cr-VI") were used* to "make enission calculations in this
report.
Table 3.3 provides analytical results of Cr-VI mass emission
testing at the Precision Engineering, Inc plant. The samples were
analyzed using lon-Chromatography with a Post Column Reactor
(ICPCR). RTIL's analytical data report is provided in Appendix D.
The average concentration at the outlet was 0.0103 mg/m3. The
average mass emission rate (Ibs/hr) of the two inlets combined was
1.44 x 10~2 Ib/hr and the outlet had an emission rate of 5.57 x 10~4
Ib/hr.
3.2.2 Total Chromium Results Froia ICP Analysis
Presented in Table 3.4 are the total chromium (CR-T) emission
results. RTIL's analytical data report is provided in Appendix D.
The Cr-T emission concentration at the outlet averaged 0.0108
mg/m3. The average Cr-T mass eiaission rate from Inlets No. 1 and
No. 2 combined was 1.51 x 10"2 Ib/hr and the outlet average emission
rate was 5.83 x 10~* Ib/hr.
3-4
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Table 3.2. COMPARISON OF EMISSION SAMPLE
ANALYSIS RESULTS' FOR CHROMIUM-VI USING
COLORIMETRY" AND ICPCR£ TECHNIQUES
Inlet No. 1
Test Run No.
Run No.l
Run No. 2
• Run -No-. 3 •
Sampling Time
(min)
360
240
240
Total Cr-VI G*g)
Colorimetryb
2,862
743
:~ .. 848
Average 1,484
ICPCR'
2,889
1,774
. .2,891
2,518
Inlet No. 2
Run No. 1
Run No. 2
Run No. 3
Average
360
240
240
1,517
808
779
1,035
1,589
770
813
1,057
Outlet
Run No. 1
Run No. 2
Run No. 3
360
240
240
123
37.8
50.3
Average 70.4
146
60.6
53.5
86.7
' Results are expressed as total microgram of Chromium-VI
b Colormetric quantification on-site using diphenylcarbazide organic analytical reagent
c lon-chromatography with a post column reactor.
3-5
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Table 3.3. ANALYTICAL' RESULTS OF CHROMIUM-VI
MASS EMISSION TESTING
Inlets"
Test
Run No.
1
2
3
Average
Total Cr-VI
(Mg)c
4,478
2,544
3,704
3,575
Emission
Concentration
(mg/m3)'
Mass
Emission Rate
(lb/hr)c
1.30 X 10'2
1.175 x 10-2
1.838x ia2
1-44 x 10'2
Mass
Emission
Rate
(kg/hr)'
5.93 X ID'3
5.33 x ID"3
8.33 x lO'3
6.53 x 10~3
Outlet
Test
Run No.
1
2
3
Average
Total Cr-VI
fog)0
146
60.6
53.5
86.7
Emission
Concentration
(mg/m3) c
0.0139
0.0093
0.0078
0.0103
Mass
Emission
Rate
(Ib/hr)'
7.45 x 10-"
4.91 x 10-*
4.34 x 10-*
5.57 x 10~4
Mass
Emission
Rate
(kg/hr)e
3.38 X 10-4
2.22 x 10-4
1.97 x 1O4
2.52 x 10"1
NOTE: The concentration in milligrams per cubic meter for the two
inlets combined is omitted from the inlet data. Since the flow
rates for the two inlets were different, a combined concentration
number would not reflect the concentration of either inlet and is
not needed in this report. Inlet #1 averaged 0.3364 Mg/M3 of
hexavalent chromium while Inlet #2 averaged 0.1353 Mg/M3 of
hexavalent chromium.
• Analysis method, lon-Chromatography with Post Column Reactor.
b The control device has two inlets (Inlet No. 1 and Inlet No.2).
e Sum of Cr-VI emissions from Inlet No.l and Inlet No.2.
3-6
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Table 3.4. ANALYTICAL1 RESULTS OF TOTAL CHROMIUM
MASS EMISSION TESTING
InJetsb
Test
Run No.
1
2
3
.Average
Cr-T Oig)c
4,602
2,728
3,921
3,750 .
Emission
Concentration
(mg/m3)1
-- • -.
Mass Emission
Rate
flb/hr)e
1.35 X ID'2
1.25x 10"2
1.93x lO"2
1.51 x 10'2
Mass Emission
Rate
(kg/hr)c
6.14 x lO'3
5.656 x 10-3
8.741 x 10"3
6.846 X 10"
Outlet
Test
Run No.
1
2
3
Average
Cr-T 0*g)e
137.0
68.3
61.3
88.9
Emission
Concentration
(mg/m3)'
0.0131
0.0105
0.0089
0.0108
Mass Emission
Rate
(lb/hr)c
6.99 x ID"1
5.53 x 104
4.97 x 104
5.83 X 10"4
Mass Emission
Rate
(kg/hr)c
3.17 x 1CT4
2.51 x 10-*
2.26 x 10-1
2.65 X ID'4
NOTE: The concentration in milligrams per cubic meter for the two
inlets combined is omitted from the inlet data. Since the flow
rates for the two inlets were different, a combined concentration
number would not reflect the concentration of either inlet and is
not needed in this report. Inlet #1 averaged 0.3492 Mg/M3 of total
chromium while Inlet #2 averaged 0.1478 Mg/M3 of total chromium.
1 Analysis method, Inductively Coupled Plasma (ICP)
b The control device has two inlets (Inlet No. 1 and Inlet No. 2)
c Sum of total chromium emissions from Inlet No. 1 and Inlet No. 2
3-7
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3.3.3 Concentrations In Plating Tank Solution. MPME Water and Train Blank Samriles
Cr-VI and Cr-T concentrations in the plating tank solution, MPME water and train blank
samples were determined by RTIL using ICPCR and ICP. The sample concentrations are
presented in Table 3.5. The concentrations of chromium remained essentially constant
throughout the testing period.
3.3.4 Computerized Spreadsheet Calculations
A computerized spreadsheet, provided by Mr. Frank Clay (U.S. EPA, Task Manager), was used
to calculate the emission cbncenIraQons"aTfd""niass emission rates in this report. Manual
calculations were made by AST personnel to verify that the computer results were accurate. The
computer printouts are provided in Appendix A. Appendix F presents the equations used to
make these manual verifications.
3.3.5 Removal Efficiency of The Mesh Pad Mist Eliminator
Chromium removal efficiencies for the MPME system were determined by simultaneously
sampling the two inlets and outlet of the MPME. The mass emission rates were used to
calculate removal efficiencies. Removal efficiency is calculated using the equation below.
Crc0
RE = — — - x 100
C,
Where:
RE - % Removal Efficiency
of mass emission rates at Inlets 1 and 2, Ib/hr
C0 = Mass emission rate at the outlet, lb\hr
3-8
-------
Table 3.5. ANALYSIS OF PLATING TANK SOLUTIONS,
MPME WATER AND BLANK SAMPLES
SAMPLES*
Tank 1 Run No. 1
Tank 1 Run No. 2
Tank 1 Run No. 3
Tank 2 Run No. 1
Tank 2 Run No. 2
Tank 2 Run No. 3
Tank 7 Run No. 1
Tank 7 Run No. 2
Tank 7 Run No. 3
Sampling Train
Blank c
MJ Outlet Run No. 1
MJ Outlet Run No. 2
MJ Outlet Run No. 3
Cr-VP Oig/ml)
1.22x 10+5
8.59 x 10+4
1.08x 10+5
1.15x 10+5
1.22x 10+s
1.14x 10+5
1.23x 10+5
1.23x 10+5
1.20x 10+s
7.37 x lO'3
7.59 x lO'2 (6.4 x 10-2")
7.43 x lO'2 (5.00 x 10-2")
1.81 x 10"' (2.03 x 10-1")
Cr-1* Otg/ml)
1.31 x 10+s
1.30x 10+s
1.26x 10+s
1.27 x 10+s
1.25x 10+5
1.24 x 10+s
1.23x 10+5
1.26 x 10+5
1.25x 10+5
3.20 x 10'2
2.69 x 10'1
2.86 x 10'1
6.00 x lO'3
* Liquid grab samples from tanks 1, 2, 7 and the MPME were collected at the beginning,
middle and end of each Method 13-B run. All samples are composites.
• ICPCR was used for analysis
b ICP was used for analysis
e The Method 13-B sampling train was cleaned between test runs. The blank sample, is a
rinseate, was collected after cleaning the train components.
** In-field colorimetric analysis results for MPME water
3-9
-------
kass e'mission rates are presented in Tables 3.3 2nd 3.4. The data in Tables 3.3 and 3.4
indicate that more than 95% of the mass emissions are of Cr-VI and less than 5% of the
emissions are of Cr-in.
3.3.6 Penetration of The Mesh Pad Mkt Eliminator
Penetration can be used to evaluate the performance of a chromium emission control device such
as a MPME. Penetration is defined as the percentage of chromium that escapes or is not
collected by an emission control device. Percent penetration is calculated using the equation
below.
Percent Penetration= 100% - RE
Where:
RE = % Removal Efficiency
Often, the percent penetration results reveal more about the process conditions than the percent
efficiency results.
The calculated removal efficiencies are tabulated in Table 3.6. The average removal efficiency
for Cr-VI was 95.94%. The average removal efficiency for Cr-T was 95.96%. The removal
efficiencies for Cr-T and Cr-VI are essentially the same. As pointed out earlier, most of the
mass emissions are of Cr-VI (—95%). The percent penetration for each test run was also
calculated. Table 3.7 lists the results of the removal efficiency and the percent penetration
calculations. Table 3.7 shows that about 4% of the chromium emissions penetrated the mesh
pad mist eliminator.
3-10
-------
iaoie
CHROMIUM REMOVAL EFFICIENCIES
Analyte
Cr-VI
Cr-VI
• cr-vr
Average
Cr-T
Cr-T
Cr-T
Average
Analytical
Technique
Used
ICPCR
ICPCR
ICPCR ~
NA
ICP
ICP
ICP
NA
Test
Run
No.
1
2
' 3 "
NA
1
2
3
NA
Mass
Emission
Rates at
Inlets No. 1
and No. 2*
(Ib/hr)
1.307 X 10'2
i.nsx icr2
• -"1.838 x 10-2
1.440 x 10'2
1.353 x 10"2
1.247x 10-2
1.927x 10-2
1.509 x 10'2
Mass
Emission
Rate at
Outlet
(Ib/hr)
7.449 X 10"*
4.906 x 10"
4.340 x 10"
5.65 x 10-*
6.990 x 10'4
5.530 X 10"
4.972 x 10"
5.831 x 10~*
Removal
Efficiency
(%)
94.30
95.82
97.64
95.92
94.83
95.57
97.42
95.94
* - Inlets 1 and 2 mass emission rates were combined.
NA - Not Applicable
3-11
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Table 3.7. REMOVAL EFFICIENCY AND PERCENT
PENETRATION* OF CHROMIUM THROUGH THE
MESH PAD MIST ELIMINATOR
Test Run No.
1
. .. 2.
3
Average
% Removal Efficiency
Cr-VI
94.30
95.82
97.64
95.92
Cr-T
94.83 -
95.57
97.42
95.94
% Penetration
Cr-VI
5.70
4.18 .
2.36
4.08
Cr-T
5.17
4.43
2.58
4.06
Percent Penetration = 100% - % Removal Efficiency
3-12
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