EMISSIONS FROM SLUDGE INCINERATORS WITH
VENTURI AND TRAY SCRUBBERS AND WET ELECTROSTATIC PRECIPITATORS -
METALS, CHROMIUM AND NICKEL COMPOUNDS, AND ORGANICS
Harry E. Bostian
U.S. Environmental Protection Agency,
Cincinnati, Ohio
William G. DeWees
DEECO Inc.
Gary, North Carolina
Eugene P. Grumpier
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina
F. Michael Lewis
F. Michael Lewis Inc.
El Segundo, California
INTRODUCTION
The U.S. Environmental Protection Agency (EPA) Office of Water (OW) has been
developing new regulations for municipal wastewater sludge incinerators. EPA's Risk
Reduction Engineering Laboratory (RREL) has been assisting OW in the collection of
supporting data for the proposed regulations. There is particular concern regarding
chromium and nickel species in the emissions from incineration of municipal wastewater
sludge because of the associated cancer risk. OW has drafted risk-based sludge regulations
under Section 405d of the Clean Water Act which have been published for comment in the
Federal Register. Volume 54, No. 23, February 6,1989. Final regulations are scheduled for
publication in the Federal Register. July 31, 1992.
The draft regulations were based on the risk incurred by the "most exposed
individual" (MEI). The MEI approach involves calculating the risk associated with an
individual residing for seventy years at the point of maximum ground level concentration of
the emissions just outside the incinerator facility property line. EPA's proposal for
regulating municipal wastewater sludge incinerators was based on ensuring that the
increased ambient air concentrations of metal pollutants emitted from sludge incinerators
are below the ambient air human health criteria. The concentrations were identified in the
proposed regulations as Risk Specific Concentrations (RSCs). Both nickel and chromium
emissions from sludge incinerators presented a specific problem in establishing RSCs,
because unknown portions of the emissions of these metals are in forms which are harmful
to human health. In performing the risk calculations, EPA assumed that 1% of the
emissions of chromium from the sludge incinerators is in the most toxic form, hexavalent
369
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chromium. This was based on limited data. For nickel, EPA assumed that 100% of the
nickel emissions are in the most toxic form, nickel subsulfide. Ho data on nickel subsulfide
were available so the most conservative approach was taken. The lack of a substantial data
base on hexavalent chromium and nickel subsulfide emissions prompted EPA to plan
additional measurements of these constituents in sewage sludge incinerator emissions.
A comprehensive test program was developed to determine the ratios of hexavalent
to total chromium and nickel subsulfide to total nickel for a typical municipal wastewater
sludge incinerator under normal combustion conditions (higher concentrations of carbon
monoxide and total hydrocarbons)-and improved combustion conditions (-lower
concentrations of carbon monoxide and total hydrocarbons). Emissions of metals,
hexavalent chromium, nickel subsulfide, polychlorinated dibenzQdioxins and furans
(PCDD/PCDFs)t semi-volatile and volatile organic compounds, carbon monoxide (CO), and
total hydrocarbons (THCs) from two multiple hearth incinerators and a fluidized bed
incinerator were measured. The emissions were controlled at each unit with venturi
scrubbers and, on two of the units, emissions from wet electrostatic precipitators (ESPs)
were determined. Flue gas sampling was conducted at the inlet and outlet of the air
pollution control devices at three separate sites. - Feed sludge was tested for metals,
moisture, and carbon and hydrogen content Two additional tests at two other sites were
conducted to evaluate sampling and analysis of hexavalent chromium and continuous
emissions monitoring systems (CEMS) for CO and THC. Gas concentrations, mass emission
rates, metals-to-particulate ratios, and emissions factors were reported. Analytical results
for the process samples were reported. Isomer-specific PCDD/PCDFs and semi-volatile and
volatile organic compound concentrations were reported. CEMS results for SOj, NOX, COB
CO, and THC were also presented.
This paper presents the key findings from that five-site research project. That project
is fully documented in the individual site emission test reports that are listed in the
Bibliography.1"*
OBJECTIVES
The objective of this study was to collect additional data on the emissions of metals,
hexavalent chromium, nickel subsulfide, PCDD/PCDFs, semi-volatile and volatile organic
compounds from municipal wastewater sludge incinerators. In the process of collecting this
data, new methodology was developed and employed to determine emissions of hexavalent
chromium and nickel subsulfide.
SAMPLING AND ANALYTICAL PROCEDURES
At Site 5 (continuing a numbering system initiated in a previous four-site project)
tests were only conducted for methods development purposes. At Site 6, emissions were
measured at the inlet and outlet of the control device. At Site 7, an evaluation of CO and
THC CEMSs was performed. At Sites 8 and 9, emissions were measured at the inlet of the
venturi/scrubber, at the midpoint located between the venturi scrubber "and the wet ESP,
and at the outlet of the wet ESP. For Sites 6,8, and 9, midpoint and/or outlet air emission
370
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samples were collected and analyzed for paniculate matter, metals, PCDD/PCDFs, volatile
and semi-volatile compounds (except Site 6), and hexavalent chromium and nickel subsulfide
species. Continuous emission monitoring (CEM) for O2, CO* CO, SO* and NO, was
conducted at the control system inlet and O2 (except Site 6), CO2 (except Sites 6 and 9), CO,
SO2 (except Sites 6 and 9), NO, (except Sites 6 and 9), and THC was conducted at the
control system outlet stack. The monitoring data were used principally to determine process
and control equipment operating conditions during the chromium and nickel speciation tests.
Process samples consisting of sludge feed, scrubber inlet water, scrubber discharge water,
and bottom ash (except Site 8) were collected. Process samples were analyzed for metals
and were subjected to ultimate and proximate analyses.
Paniculate matter and metals sampling was conducted following the procedures in
the draft EPA method, "Methodology for the Determination of Trace Metals Emissions in
Exhaust Gases from Stationary Source Combustion Processes" (see Bibliography, Emissions
of Metals, Chromium and Nickel Species, and Organics from Municipal Wastewater Sludge
Incinerators, Volume IX).
Flue gas sampling and analysis for hexavalent chromium followed the procedures in
the draft EPA method, "Determination of Hexavalent Chromium from Stationary Sources"
(see Bibliography, Emissions of Metals, Chromium and Nickel Species, and Organics from
Municipal Wastewater Sludge Incinerators, Volume IX). This sampling train continuously
recirculated the impinger solution to the sample nozzle to prevent conversion of hexavaleiy
chromium during sampling. A radioactive hexavalent chromium isotope was used 1) to
verify that conversion to trivalent chromium was not significant and, 2) for determination
of hexavalent chromium (surrogate) recovery. Hexavalent chromium in the samples was
detected by ion chromatography coupled to a diphenylhydrazine post-column reaction
(IC/PCR) system after filtration of the impinger solutions.
Flue gas sampling and analysis for nickel species followed .the draft EPA method,
"Methodology for the Determination of Nickel Compound Emissions from Stationary
Sources." Analysis of the nickel speciation samples was performed following the Nickel
Producers Environmental Association (NiPERA) sequential leaching method (see
Bibliography, Emissions of Metals, Chromium and Nickel Species, and Organics from
Municipal Wastewater Sludge Incinerators, Volume IX). The ratios of sulfidic nickel
species, nickel subsulfide (Ni3Sz) and nickel sulfide (NiS), to total Ni were determined.
Flue gas sampling for PCDD/PCDFs and semi-volatile organic compounds followed
procedures in SW-846 Method 0010, except that a final toluene rinse was conducted and
analyzed separately for PCDD/PCDFs. The samples were analyzed for PCDD/PCDFs
using SW-846 Method 8290 and for other semi-volatile organic compounds using a
combination of SW-846 Methods 3540, 3550, 3510, 3520, and 8270 (see Bibliography, Test
Methods for Evaluating Solid Waste).
Flue gas sampling for volatile organic compounds employed the volatile organic
sampling train (VOST) in accordance with SW-846 Method 0030 (see Bibliography. Test
Methods for Evaluating Solid Waste).
371
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EPA Methods 1 (sample point determination), 2 (velocity and flow rate
determination), 3 (molecular weight and excess, air determination), and 4 (moisture
determination) were used in conjunction with the sampling procedures described above.
Method 3 samples were collected as a backup for O2 and CO2 determination should the
CEMSs data be unavailable.
The CEMSs used to measure concentrations of CO, CO2 and O* NO,, SO2, and total
hydrocarbons (THC as propane) followed EPA instrumental Methods 10, 3A, 7E, 6C, and
25A, respectively,. The primary intent of the continuous monitoring effort was to: (1)
determine concentrations of these compounds, and (2) provide a real-time indication of
combustion conditions. The continuous emissions monitoring systems were- calibrated daily,
but no attempt was made to certify the monitors using the EPA instrumental test methods.
The dewatered sludge samples were analyzed for the target metals after
determination of their moisture and ash content, heating value, and proximate and ultimate
analyses.
Incinerator and control system operating parameters were monitored during all
manual test runs to characterize the system operations.
RESULTS AND DISCUSSION
Metals and Paniculate
Metals and sludge feed rates to the incinerators are shown in Table 1 for both
normal and low CO (improved combustion) conditions. Chromium, lead, and nickel
consistently had the highest metals feed rate to the incinerators. At Site 6, chromium had
the highest feed rates (48 and 58 g/hr) due to contamination in the ferric chloride used to
condition the sludge at this site. At Site 6, lead had the second highest feed rate (11 g/hr).
At Site 8 and Site 9, lead had the highest feed rates (39 g/hr and 189-228 g/hr,
respectively). Chromium had the second highest feed rate (30 g/hr) at Site 8, followed by
nickel (19 g/hr). At Site 9, nickel had the second highest feed rates (120 and 152 g/hr),
followed by chromium (76 and 85 g/hr).
1 In Table 2, paniculate matter and metals emissions factors from the control device
outlets are shown for normal and low CO conditions. The paniculate matter emission factor
represents the mass of paniculate emitted per mass of dry sludge fed. The metals emission
factors represent the mass of metals emitted per gram of metal fed to the incinerator in the
sludge. For paniculate matter, the emission factors were 0.28 g/kg and 0.39 g/kg for Site
6 at normal and low CO conditions, respectively, and 0.011 g/kg without the wet ESP and
0.003 with the wet ESP for Site 8. For Site 9, the paniculate emission factors for normal
combustion without the wet ESP was 0.21 g/kg and for low CO combustion and with the
wet ESP was 0.04 g/kg. Cadmium had the highest emission factor of all the metals for each
of the sites, ranging from 0.0003 g/g for Site 8 to 0.917 g/g for Site 6 with normal
combustion. At Site 6, the lead emission factor increased from 0.123 to 0.136 with improved
combustion (higher hearth temperatures). At Site 9, the addition of the wet ESP lowered
372
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the lead emission rate from 0.101 to 0.006 g/g even with improved combustion and higher
hearth temperatures. Due to the high collection efficiency of the venturi
scrubber/impingement tray scrubber, metal emission factors were considerably lower for the
fluidized bed incinerator at Site 8 compared to the multiple hearth incinerators at Site 6 and
at Site 9 without the wet ESP. With the wet ESP, the emission factors from Site 9 were
comparable to both Site 8 and Site 3, (a fluidized bed incinerator tested during preliminary
studies on sludge incineration). The lower emission factors seen for the fluidized bed
incinerators may have been due to less volatilization and/or better removal with larger
panicles. The reader is cautioned however, against making a general conclusion that fluid
beds with conventional venturi and tray scrubbers can, as a general rule, perform as well as
multiple hearths with both the conventional scrubbers and a wet ESP. The data presented
here are from only a few incinerators. Also, individual performance depends upon design
criteria, installed equipment, operation, degree of design loading, sludge being processed,
etc. These factors vary from facility to facility and offer only so much flexibility at any one
location.
At Sites 6, 8, and 9, the metals were measured at the venturi/scrubber inlet and
outlet and at the outlet of the wet ESP for Sites 8 and 9. The removal efficiencies were
calculated and are summarized in Table 3. Arsenic and beryllium were essentially not
detectable at all three sites and are not included in the table. For Sites 6 and 9 with
multiple hearth furnaces and venturi/scrubbers, only chromium and nickel had removal
efficiencies within 10% of the paniculate matter removal efficiency. At Site 6, cadmium and
lead had removal efficiencies of about 71% at normal combustion conditions and about 77%
at low CO conditions compared to about 98% paniculate matter removal efficiency. For
Site 9, cadmium and lead had even lower removal efficiencies of 45% and 54%, respectively,
at low CO conditions compared to 95% paniculate matter removal efficiency. For Site 8,
with a fluidized bed and venturi/scrubber, cadmium, chromium, lead, nickel, and paniculate
matter had similar removal efficiencies of >99%. The pilot-scale wet ESP at Site 8
removed an additional 62% to 96% of the metals and paniculate matter emitted from the
venturi/scrubber. At Site 9, the full-scale ESP removed an additional 87% to 98% of the
metals and paniculate matter emitted from the venturi/scrabber.
*
The ratios of individual metals to paniculate matter for Sites 6, 8, and 9 at normal
and low CO conditions are summarized in Emissions of Metals, Chromium and Nickel
Species, and Organics from Municipal Wastewater Sludge Incinerators, Volume I. For Site
6 (normal and low CO conditions) and Site 9 (normal conditions only), lead had the highest
metals-to-particulate ratios at 28 and 32 -mg/g (Site 6) and 12. mg/g (Site 9), followed by
cadmium, at 1.6 and 2.0 mg/g (Site 6) and 2.0 mg/g(Site 9).-' In contrast, at Site 8, the ratio
of metals to paniculate matter for chromium was 1.1 mg/g and for cadmium was 0.4 mg/g.
Generally, the ratio of metals to paniculate matter was lower for the fluidized bed
incinerator (Site 8) than for the multiple hearth incinerators (Sites 6 and 9). At Site 6, the
ratios of metal to paniculate matter for cadmium, chromium, and nickel decreased from
normal operating conditions to the low CO conditions, and increased for lead from normal
operating condition to low CO operating conditions. At Site 9, the wet ESP at the low CO
condition had lower ratios for cadmium, chromium, and lead and a higher ratio for nickel
compared to the normal condition without the wet ESP. The ratio of lead to paniculate
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matter was lower at Site 8 compared to Site 6 even though the feed rate of lead at Site 8
was 15-20 times higher than Site 6.
It must be emphasized that the elevation in temperatures of the multiple hearths to
obtain low CO and improved organics removals was not made under the most favorable
circumstances as far as metals are concerned. Because the project was a short term project,
only minimal modifications were made and temperatures were raised near the middle of the
furnace because burner capacity existed there. Although the object was to remove organics
from the emissions, the sludge solids were also heated considerably with this procedure, with
accompanying release of the more volatile metals. With proper retrofitting for the purpose
of permanent changes in process capabilities, an afterburner or more burner capacity would
be added at the top of the furnace, not the middle.' This approach would heat emissions
more than sludge solids and should not result in nearly as high metals emissions.
Hexavalent Chromium and Total Chromium
A major accomplishment of this test program was the sampling of hexavalent
chromium without artifact formation, and analysis of the resulting samples specifically for
hexavalent chromium at low concentrations. Sampling activities conducted at Site 5 were
dedicated to developing a suitable measurement method for hexavalent chromium in
emissions from incineration of municipal wastewater sludge. Hexavalent chromium sampling
at the venturi/scrabber outlets at Site 6,8, and 9 followed the same procedures as the draft
EPA method. A new sampling technique was developed for this program where the
impinger reagent is constantly recirculated to the inlet end of the sampling probe. A key
element used to verify the results of this sampling technique was the use of the a hexavalent
chromium radioactive isotope, 5lCr**, incorporated into each sampling train as a surrogate.
With the recirculating train design, the surrogate added to the impinger solution at the start
of the test was exposed to the same conditions within the train as the native hexavalent
chromium. The MCr** surrogate measured the degree of conversion of hexavalent
chromium to trivalent chromium occurring during sampling and handling of samples prior
to analysis. The surrogate recoveries for Sites 6, 8, and 9 at both midpoint and wet ESP
outlets and the ratio of hexavalent to total chromium measured with the recirculating train
are shown in Table 4.
Surrogate recoveries ranged from 67 to 96% during sampling at the venturi/scrubber
outlet at Sites 6, 8, and 9. For samples taken at the wet ESP outlets at Site 8 and 9,
surrogate recoveries ranged from 82 to 91%. The ratio of hexavalent chromium to total
chromium measured by the recirculating train at the venturi/scrubber outlets ranged from
< 1.8 to 29.9%, and at the wet ESP outlets, the ratio ranged from < 1.4 to 42.5%. (The
hexavalent to total chromium ratios were not corrected for surrogate recovery). At Site 6,
the hexavalent-to-total chromium ratio increased from 1.9% to 83% between the normal
combustion conditions and the low CO (improved combustion) conditions. An explanation
for this observation, shown graphically in Figure 1, is that the higher hearth temperatures
and excess oxygen levels recorded during the improved combustion conditions favor the
formation of hexavalent chromium. This effect was not seen at Site 9. The fluidized bed
incinerator at Site 8 had the lowest ratio of hexavalent to total chromium in the
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venturi/scnibber emissions. A possible explanation for this low ratio at Site 8 is the lower
residence time that occurs in the fluidized bed incinerator (seconds) compared to the higher
residence time that occurs in multiple hearth incinerators (hours). .
Nickel Subsulfide
The major objective of the nickel speciation testing was to determine the percent of
the nickel emissions in the form of nickel subsulfide. It was anticipated that the nickel
subsulfide emissions from multiple hearth incinerators would constitute less than 1% of the
total nickel emissions, because these incinerators typically operate with high excess air which
is not favorable for the formation of nickel subsulfide. The results of the sequential
leaching nickel analysis indicate that within the detection limit of the wet chemical method,
no nickel subsulfide was present in the samples. Based on the detection limits, the nickel
subsulfide-to-total nickel ratio at Sites 6 and 8 was less than 12% for the inlet emissions and
less than 10% for the outlet emissions. Samples analyzed from the same runs by X-Ray
Absorption Near-Edge Structure (XANES) and Extended X-Ray Absorption Fine Structure
(EXAFS) indicated that no nickel subsulfide was detected within the instrumental detection
limit of 10% of the total nickel. For Site 9, the ratio of nickel subsulfide to total nickel in
the inlet emissions was less than 2 % and in the midpoint emissions was less than 1%. (The
reduction in the analytical detection limit was due to the higher amounts of total nickel
present in the emissions).
Polychlorinated Dibenzodioxins and Furans
Sampling for PCDD/PCDFs was performed at the venturi scrubber outlet at Sites
8 and 9 (termed the Midpoint at Site 9) and also at the wet ESP outlet at Site 9. Sampling
at Site 9 was conducted at both normal and low CO conditions. The results for the
PCDD/PCDF sampling are shown in Table 5. Total tetra-octa chlorinated dibenzodioxins
and furans (CDD + CDFs) were the highest (102 ng/dscm) at the venturi/scrubber outlet
at Site 9 during normal conditions. Improved combustion at Site 9 lowered the total tetra-
octa CDD + CDF emissions from 102 ng/dscm to 8.7 ng/dscm. The wet ESP at Site 9
reduced the total tetra-octa CDD + CDF emissions from 102 ng/dscm to 15.6 ng/dscm
under normal conditions and from 8.7 ng/dscm to 2.8 ng/dscm under the low CO condition.
Total tetra-octa CDD + CDF emissions at the venturi/scrubber outlet at Site 8 were 2.1
ng/dscm compared to 102 and 8.7 ng/dscm for Site 9 at normal and low CO conditions,
respectively.
Semi-volatile Organic Compounds and Volatile Organics
At Site 9, sampling for semi-volatile organic compounds was performed at the
venturi/scrubber outlet and the wet ESP outlet under both normal and low CO conditions.
The results for the semi-volatile organic compound sampling are shown in Table 6. Several
compounds were found above the minimum detection limit at both the midpoint and outlet
locations. The concentrations and number of the semi-volatile compounds detected were
typically less under the low CO combustion conditions. At normal combustion conditions,
eleven semi-volatile compounds were detected for both runs: 1,4-dichlorobenzene, benzyl
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alcohol, 1,2-dichlorobenzene, 2-nitrophenol, benzole acid, 1,2,4-trichlorobenzene,
naphthalene, . 2-methylnaphthalene, dibenzofuran, phenanthrene, and
bis(2-ethylhexyl)phthalate. At low CO combustion conditions, five semi-volatile compounds
were detected for both sample runs: phenol, benzyl alcohol, 4-methylphenol, benzoic acid,
and 4-nitrophenol. Bis(2-ethylhexyl)phthalate was found in the sample blank and the
emission results are likely due to contamination.
The concentrations of the volatile organics in the flue gas are presented in Table 7.
At Site 8, five of the target compounds were below the analytical detection limit during all
three test runs: acrylonitrile, vinyl chloride, 1,2-dichloroethane, and chlorobenzene. The
other eight target compounds were detected in all three test runs and average values are
given in Table 7. At Site 9, two of the target compounds were below the minimum detection
limit during all three test runs: 1,2-dichloroethane and carbon tetrachloride. Vinyl chloride
was measured in only two of the tube pairs. The other ten target compounds were detected
for all three test runs and average values are given in Table 7.
Carbon Monoxide, and Total Hydrocarbon
Continuous Emissions Monitoring
At Sites 6 and Site 9, a positive correlation between carbon monoxide emissions and
total hydrocarbon (THC) emissions was observed. This relationship is shown graphically for
Site 6 and Site 9 in Figures 2 and 3, respectively. At Site 8, both the CO and THC
emissions were significantly low and a correlation could not be seen.
At Sites 6 and 9, the concentrations of THC and CO were reduced by about 75%
during the improved combustion conditions. At Site 7, a positive correlation was
demonstrated between the "Hot" and "Cold" THC CEMs.
CONCLUSIONS
The accomplishments of the study were far greater than could have been anticipated
at the outset of the program. Specifically, the following has been accomplished.
• Documented hexavalent chromium emissions from municipal wastewater sludge
incinerators.
• Documented nickel subsulfide emissions from municipal wastewater sludge
incinerators.
Developed a hexavalent chromium- sampling and analytical method.
Developed a nickel speciation sampling and analytical method.
Provided additional metals data.
Provided additional trace organics data.
Documented a correlation between CO and THC.
Documented that CO and THC concentrations can be reduced when the plant has
a CO and/or THC monitor to improve combustion conditions. At Site 6,
improved conditions caused an increased in hexavalent chromium concentrations.
Demonstrated that the use of a wet ESP is a viable retrofit option for significantly
reducing paniculate and metals emissions.
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The full reports were submitted in fulfillment of Contract No. 68-CO-0027 under the
sponsorship of the U.S. Environmental Protection Agency.
BIBLIOGRAPHY
1. Emissions of Metals, Chromium and Nickel Species, and Organics from Municipal
Wastewater Sludge Incinerators, Volume I: Summary Report, EPA/600/R-92/003a,
NTIS No. PB92-151554/AS.
2. Emissions of Metals, Chromium and Nickel Species, and Organics from Municipal
Wastewater Sludge Incinerators, Volume H: Site 5 Test Report -• Hexavalent
Chromium Method Evaluation, EPA/600/R-92/003b, NTIS No. PB92-151562/AS.
3. Emissions of Metals, Chromium and Nickel Species, and Organics from Municipal
Wastewater Sludge Incinerators, Volume HI: Site 6 Test Report, EPA/600/R-
92/003c, NTIS No. PB92-151570/AS.
4. Emissions of Metals, Chromium and Nickel Species, and Organics from Municipal
Wastewater Sludge Incinerators, Volume IV: Site 6 Test Report - Appendices,
EPA/600/R-92/003d, NTIS No. PB92-151588/AS.
5. Emissions of Metals, Chromium and Nickel Species, and Organics from Municipal
Wastewater Sludge Incinerators, Volume V: Site 7 Test Report - CEMs Evaluation,
EPA/600/R-92/003e, NTIS No. PB92-151596/AS.
6. Emissions of Metals, Chromium and Nickel Species, and Organics from Municipal
Wastewater Sludge Incinerators, Volume VI: Site 8 Test Report, EPA/600/R-
92/003f, NTIS No. PB92-151604/AS.
7. Emissions of Metals, Chromium and Nickel Species, and Organics from Municipal
Wastewater Incinerators, Volume VII: Site 8 Test Report - Appendices, EPA/600/R-
92/003g, NTIS No. PB92-151612/AS.
8. Emissions of Metals, Chromium and Nickel Species, and Organics from Municipal
Wastewater Incinerators, Volume VIII: Site 9 Test Report, EPA/600/R-92/003h,
NTIS No. PB92-151620/AS.
9. Emissions of Metals Chromium and Nickel Species, and Organics from Municipal
Wastewater Incinerators, Volume IX: Site 9 Test Report - Appendices, EPA/600/R-
92/003i, NTIS No. PB92-151638/AS.
10. U.S. Environmental Protection Agency, Office of Solid Waste, 1986, Test Methods
for Evaluating Solid Waste. Volumes 1A - 1C: Laboratory Manual,
Physical/Chemical Methods, SW-846, 3rd Edition, Document Control No. 995-01-
00000-1, 1986.
377
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11. Radian Corporation, 1987, Emissions of Metals and Organics from Municipal
Wastewater Sludge Incinerators, Volume V: Site 3 Final Emission Test Report, EPA
600/2/91/007e, NTIS No. PB91-151522/AS.
ACKNOWLEDGEMENTS
The work described in this paper was funded by the U.S. Environmental Protection
Agency's Risk Reduction Engineering Laboratory and Office of Water under Contract No.
68-CO-0027.
TABLE 1. FEED RATES FOR METALS IN THE SLUDGE (g/hr).
METALS
Beryllium
Cadmi urn
Chromium
Lead
Nickel
Site 6
Normal
0.05
0.82
57.9
11.4
4.41
Site 6
Low CO
0.05
0.78
48.0
11.6
3.42
Site 8
Normal
0.27
2.20
30.0
39.0
19.0
Site 9
Normal
ND
8.60
75.7
189
120
Site 9
Low CO
ND
8.75
85.3
228
152
Total Sludge
Feed Rate
(Ibs/hr) 3733 3460 4966 7482 7460
Dry Solids
Feed Rate
(Ibs/hr) 971 934 979 1571 1641
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TABLE 2. PARTICIPATE (PM) AND METALS STACK EMISSION FACTORS AT NORMAL AND LOW
CO OPERATION.
SITE,
CONDITIONS:
LOCATION:
SITE 6,
NORMAL CO:
SCRUBBER
INLET:
SCRUBBER
OUTLET
LOW CO:
SCRUBBER
INLET:
SCRUBBER
OUTLET
SITE 8,
NORMAL CO:
SCRUBBER
INLET:
SCRUBBER
OUTLET
WET ESP
OUTLET:
SITE 9,
NORMAL CO:
SCRUBBER
INLET:
SCRUBBER
OUTLET:
LOW CO:
SCRUBBER
INLET:
SCRUBBER
OUTLET:
WET ESP
OUTLET:
EMISSION FACTORS
PM
(g/kg, dry
sludge feed)
20.5
0.28
16.4
0.39 .
47.3*
0.011
0.003
2.13
0.21
5.63
0.31
0.04
(g
Be
0.336
<0.069
0.038
0.059
0.66**
<0.0001
<0.0001
NO
ND
NO
ND
ND -
METALS
metal emitted/ g metal
Cd Cr
0.971 0.612
0.917 0.011
0.978 0.663
0.908 0.005
0.46** 0.48**
0.0009 0.0004
fed)
Pb
0.320
0.123
0.407
0.136
0.34**
0.0002
0.0003 0.0001 <0.0001
0.41 0.034 '
0.079 0.003
0.83 0.082
0.040 0.009
<0.008 0.001
0.10
0.017
0.30
0.014
0.006
Ni
0.313
0.030
0.286
0.013
0.40**
0.0004
<0.0001
0.04
0.0002
0.10
0.004
0.0004
ND - Not detected, all sample measurements were below the analytical detection
limtt.
< - Outlet samples were below analytical detection limit, calculated ratio is
less than value shown.
Note: Since the incinerator was a fluidized bed incinerator, the * value
should be 230 and the ** values should be 1.0. The difference is a result
of sampling and analytical error.
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TABLE 3. METALS AND PARTIOJLATE REMOVAL EFFICIENCY ACROSS THE VARIOUS CONTROL DEVICES. (X)
Site 6
Normal
Element Scrubber
Cadniun 71.9
Chromiun 99.3
Lead 71 .3
Nickel 93.4
Participate
Matter 98.5
Site 6
Low CO
Scrubber
77.3
99.4
78.1
94.5
97.6
Site 8
Normal
Scrubber
99.82
99.92
99.91
99.89
99.99
Site 8
Normal
Wet ESP
71.0
62.0
>96.0
81.0
78.0
Site 9
Normal
Scrubber
0.0
0.0
5.0
89.0
85.0
Site 9
Low CO
Scrubber
45.0
89.0
54.0
96.0
95.0
Site 9
Low CO
Wet ESP
>98.0
88.0
96.0
90.0
87.0
HA - Not Applicable
NOTE: Since different data sets were used to calculate results for Tables 2 and 3, the results may be
different. The reader oust refer to the references for detailed explanation.
TABLE 4. HEXAVALEHT CHROMIUM SAMPLING RESULTS.
SITE 6 SITE 6 SITE 8 SITE 9 SITE 9
Normal Low CO Normal Normal Low CO
X X X X X
Venturi/Scrubber Outlet
Surrogate recovery 90.5 . 95.6 66.8 84.3 90.5
Hexavalent to
total Cr ratio 1.9 8.3 <1.8 11.9 7.9
Met ESP Outlet
Surrogate recovery HA HA 81.5 90.1 93.1
Hexavalent to
total Cr ratio NA NA <1.4 29.9 42.5
NA = Not applicable
•
380
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11
10
I9
=3 8
O 6
Outlet emissions data (excludes Run 7)
0=1
1 -
0
Run 11
Run 9
r = -0.98
Run3
Run 13
40
60 80 100
CO to C02 Ratio (ppm to %)
120
Figure 1. Correlation of combustion efficiency and hexavalent to total
chromium ratio at Site 6.
TABLE 5. POLYCHLORINATED DIBENZODIOXINS AND FURANS EMISSIONS SUMMARY.
Congeners
Total Tetra-
Octa ODD
Total Tetra-
Octa CDF
Total Tetra-
Octa COD /CDF
Concentration (ng/DSCM) .
SITE 8
Normal
Outlet
0.721
1.41
2.13
SITE 9
Normal
Outlet
3.2
12.4
15.6
SITE 9
Normal
Mid-Point
20.2
81.9
I
102
SITE 9
Low CO
Outlet
0.7
2.1
2.8
SITE 9 '
Low CO
Mid-Point
1.6
7.1
8.7
381
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TABLE S. SSMIVOLATILE EMISSIONS SUMMARY FOR OUTLEf AND MIDPOINT AT SITE 9
Analyte
Phenol
1 , 4-Dichlorobenzene
Benzyl alcohol
1 , 2-Dichlorobenzene
4-Methylphenol
2-Nitrophenol
Benzole acid
1,2, 4-Tr ichlorobenzene
Naphthalene
2 -Methyl naphthalene
4-Nitrophenol
Dibenzofuran
Phenanthrene
Fluoranthene
bis (2-Ethylhexyl ) phthalate
Concentration (pg/DSCM1)
OUT-MM5-7A
NO
30.3
800
25.6
ND
196
28SO
699
976
43.4
ND
45.2
44.9
ND
29.2
MID-MM5-7
ND
33.4
1120
26.7
ND
284
3220
768
864
45.5
ND
44.7
33.4
13.3
26.1
OUT-MMS-7C
176
ND
4100
ND
21.2
43.1
5090
ND
ND
ND
97.4
ND
13.7
ND
ND
MID-MM5-7C
162
ND
3930
ND
20.6
76.4
4240
ND
ND
ND
1440
ND
ND
ND
71.6
1 = 68 Deo;, f — 29.92 inches Hg.
ND = Not detected; used as zero (0).
TABLE 7. VOLATILE ORGANICS EMISSIONS SUMMARY
voc
Acrylonitrile
Vinyl Chloride
Methylene Chloride (m/z
Chloroform
1,1, 1-Tr ichloroet hane
Trichloroethene
Benzene
Tetrachloroethene
Toluene
Chi or oben zene
Ethylbenzene
SITE 3
VENTURI / SCRUBBER
OUTLET
Concentration ,
ND
ND
= 86) 108
16.8
6.8
5.2
6.2
9.4
7.7
ND
2.6
SITE 9
WET ESP
OUTLEf
ug/dsem *
1060
66.2
38.3
24.1
17.5
24.6
6390
29.0
4080
55. S
100
* a 68 Deg. F — 29.92 inches Hg
"ND = Reported as not detected or estimated values;both expressed as zero (0}
in calculating totals and averages.
382
-------
30
28 H
W 20 -
O 18 -
JQ
co 16H
§M
TO 12
I 10 H
1 8-
O 6-
4
2 -
. 0
Outlet emissions data (excluding Run 5)
r = 0.97
200 400 600
Carbon Monoxide (ppm)
800
Figure 2. Hydrocarbon emissions versus carbon monoxide emissions, Site 6.
lay
140
130
120
110
100
E 90
Q.
Q. 80
Q" 70
i «
50
40
30
20
10
.10
RunS »
..
S/
^
Run 4 • S '
s'
/
~"
r = 0.93 /
s''
s
RunS^r- Run2 .
S \
- Runs 8. 9. 10, H^TzTand 13
• M
, ' , , , ,
0.4
0.6 0.8 . 1
(Thousands)
1.2
CO, ppm
1.4
Figure 3. Hydrocarbon emissions versus carbon monoxide emissions, Site 9.
383
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EPA Fe.m 2220-1 (Re*. 4-77) (R.»c.».)
-------
TECHNICAL REPORT DATA
(Please read Instructions on the rrrene before eomplerf
\. REPORT NO.
EPA/600/A-93/067
4. TITLE AND SUBTITLE
EMISSIONS FROM SLUDGE INCINERATORS WITH VENTURI AND
TRAY SCRUBBERS AND WET ELECTROSTATIC PRECIPITATORS -
METALS, CHROMIUM AND NICKEL COMPOUNDS, AND ORGANICS
. REPORT DATE .
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Harry E. Bostian, William G. DeWees, Eugene P. Grumpier,
and F. Michael Lewis
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND AOORESS
Risk Reduction Engineering Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-CO-0027
12. SPONSORING AGENCY NAME AND ADDRESS
Risk Reduction Engineering Laboratory—Cincinnati, OH
Office of Research and Development
U.S. environmental Protection Agency
Cincinnati, OH 45268
13. TYPE OF REPORT AND PERIOD COVERED
Published Paper
14. SPONSORING AGENCY CODE
EPA/600/14
is.SUPPLEMENTARY NOTES Project Off1cer = Dr. Harry E. Bostian (513-)569-7619; Proceedings
of "The Future. Direction of Municipal Sludge (Biosolids) Management: Where We Are and
Where We're Going". Volume I, Portland. Oregon. 7/26-30/92. p:369-383
16. ABSTRACT ....
At Site 5 (continuing a numbering system initiated in a previous 4-site
project) tests were only conducted for methods development purposes. At Site 5,
emissions were measured at the inlet and outlet of the control device. At Site 7, an
evaluation of CO and THC CEMSs was performed. At Sites 8 and 9, emissions were
measured at the inlet of the venturi scrubber, at the midpoint located between the
venturi scrubber and the wet ESP, and at the outlet of the wet ESP. For Sites 6, 3,
and $, midpoint and outlet air emission samples were collected and analyzed for
particulate matter, metals, ?CDD/?COFs, volatile and semivoiatile compounds (except
Site 6), and hexavalent chromium and nickel subsulfide species. Continuous emission
monitoring (CEM) for O7, CO,, CO, S02, and NO, at the control system inlet and 0;
(except Site 6), CO, (except Sites 6 and 9), CO, SO2 (except Sites 6 and 9), NO,"
(except Sites 6 and 9), and THC wag conducted at the control system outlet stack.
The metals found in the greatest concentration in the sludge were lead,
chromium and nickel. The need for sanpling of hexavalent chromium without artifact
formation and analysis of the resulting samples specifically for hexavalent chrcmiurr.
at low concentrations was a major accomplishment of this test program. The results
of the nickel sampling and analysis indicate that within the detection limit of the
wet chemical method, no nickel subsulfide was present in the air emissions.
At Site 6 and Site 9, a positive correlation between carbon monoxide emissions
and total hydrocarbon (THC) emissions was observed. At Site 7, a positive
correlation was demonstrated between the "Hot" and "Cold" THC CEMs.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
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c. COSATI Field/Croup
Wastewater, sludge disposal,
incinerators, combustion products
Emissions
chromium compounds
nickel compounds
total hydrocarbons
dioxin/furans
organic compounds
13. DISTRIBUTION STATEMEN1
RELEASE TO PUBLIC
19. SECURITY CLASS
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