J'/
United States
Environmental Protection
Agency
Robert S. Kerr Environmental
Research Laboratory
Ada OK 74820
Research and Development
EPA-600/S2-83-089 Nov. 1983
&EPA Project Summary
Characterization and
Treatment of Aqueous
Wastes and Residue from
Petroleum Refineries
S.L. Burks and J. Wagner
This research project was designed to
identify process wastewaters which
contained a significant proportion of
the total load of contaminants in
petroleum refinery wastewaters and to
evaluate methods for intensively treat-
ing these highly concentrated low-
volume streams. In addition, selected
waste residues from API gravity separa-
tor, dissolved air flotation units, and
"slop" oil emulsions were analyzed to
determine the presence of hazardous
chemicals as listed by the U.S. Environ-
mental Protection Agency (EPA) Office
of Solid Waste.
Process wastewaters from the fluid
catalytic cracking units, crude desalting
unit, coking unit, and barometric
condenser contained the highest levels
of contaminants. These process waste-
water streams were major contributors
to the total load of phenol, ammonia,
sulfide, and organic carbon contamina-
tion of the combined refinery waste-
waters. On-site evaluations of mixed
media filtration-activated carbon ad-
sorption and a biological oxidation
system indicated both systems were
capable of reducing phenol, sulfide, and
organic carbon levels by greater than
90 percent.
This Project Summary was developed
by EPA's Robert S. Kerr Environmental
Research Laboratory, Ada, OK, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
The major objective of this project was
to determine the relative contribution of
aqueous wastes from fluid catalytic
cracking (FCC) units and other selected
process units to the total quantity of
aqueous wastes produced within a
refinery. A parallel objective was to
evaluate the effectiveness of physical-
chemical and biological treatment systems
for intensively treating highly concen-
trated process unit wastewater systems.
Many refineries have adapted a practice
of using wastewaters from FCC units for
desalting crude oil stocks. This practice
reduces concentration of hydrocarbon
type compounds in the FCC process
wastewater by partitioning hydrocarbons
between the aqueous and oily phases. In
addition, the total volume of water used is
reduced. Most of the refineries are
attempting to conserve as much waste-
water as possible through recycle-reuse
practices. However, complete recycle-
reuse may not be economically feasible
at this time. As an alternative, existing
refineries may have to adopt a combination
of recycle-reuse and intensive treatment
of highly contaminated process waste-
water streams in order to achieve 1983-
85 effluent standards.
Phases of Investigation
Phase I (First Year)
Phase I was devoted to characterization
of the influent and effluent concentration
of aqueous wastes from FCC and other
selected process units at three refineries
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in Oklahoma and nearby states. The
characterization phase was designed to
provide quantitative information for
determination of the percentage contri-
bution from all other sources within the
refinery. Major emphasis was placed on
measurement of significant waste compo-
nents such as organic compounds,
ammonia, and sulfides.
Phase II (Second Year)
In the second year of the project, a
small, pilot-scale (0.25-gpm) dual media
filter-activated carbon treatment system
was established to operate in parallel
with an existing aerated lagoon (biopond)
system which was used to treat wastewa-
ters from a FCC unit A comparison of the
effectiveness of the pilot-scale system
with that of the full-sized aerated lagoon
system was made by measuring the
percent reduction m significant parameters
between the influent and effluent streams
The pilot-scale system and the full-sized
aerated lagoon system were sampled at
six different intervals during a 30-day test
period.
Phase III (Third Year)
The objective of this phase of the
project was to characterize priority pollu-
tants in residuals from the petroleum
refining industry. The residuals were col-
lected from the dissolved air flotation
unit, API gravity separator, and "slop" oil
residuals. The residuals were extracted
by the EPA-RCRA "Extraction Procedure"
(EP) for evaluation of solids to determine
if they contain toxic substances (CFR
45(98)33127, May 19, 1980) and by con-
ventional laboratory techniques.
Extracts from the residuals were
analyzed for toxic heavy metals by atomic
absorption spectrometry and for "priority"
organic pollutants by combination gas
chromatography-mass spectrometry
(GC-MS).
Results and Discussion
Phase 1. Collection and
Analysis of Contaminants in
Process Wastewaters
The concentration of contaminants in
the process wastewaters indicated that
the overhead contact waters from the
FCC unit contained the highest levels of
phenol, sulfide, and BOD. The FCC
process wastewater stream also contained
the second highest level of ammonia. The
overhead receiving water from the coking
unit contained highest levels of TOC and
second highest levels of BOD. The
highest levels of oil and grease detected
in a process wastewater stream were
from the barometric condenser.
The concentration of mercury, vana-
dium, cadmium, and nickel was below
detection limits for the atomic absorption
spectrometer. Detectable quantities of
lead were found in process wastewaters
from the crude desalting unit and in the
combined wastes into the API separator.
The caustic neutralizer process waste-
waters appeared to be a major contributor
of chromium, zinc, copper, iron, potassium,
and sodium. Most of the calcium was
found in the crude desalting unit waste-
waters, although several other waste
streams contributed significant quantities
of calcium also.
Analyses of specific organic compounds
in the process wastewaters by GC-MS
indicated that the waste from the caustic
neutralizer and the influent to the API
separator contained the greatest number
of compounds which could be identified.
The most common classes of organic
compounds identified in the process
waste streams were aliphatic (Cio H22to
C23 HUa), monocyclic aromatics, and alkyl
aromatrcs. Only three polynuclear aro-
matic hydrocarbons were identified —
fluorene, phenanthrene/anthracene,
and methyl anthracene. These compounds
were found in the caustic neutralizer
wastewater. None of the aromatic, alkyl
aromatic, or polynuclear aromatic com-
pounds were detected in the final
effluent, which would indicate that the
biological treatment system at this
refinery was effectively removing these
compounds The major class of compounds
identified in the final effluent was
aliphatic hydrocarbons, a homologous
series from Ci3 H2s to C2oH42.
Phase 2. Comparison of Pilot-
Scale Mixed Media Filter-
Activated Carbon (MMF-AC)
versus Biopond Treatment of
Sourwater Stripper Process
Wastewater
The calculated mean percentage re-
moval of phenol by the biopond was
99.8% and for the MMF-AC pilot-scale
treatment unit 99.99% (Table 1). The
mean concentration of phenol in the
effluent from the SWS unit was 203
mg/l with a range from 175 to 233 mg/l
in the first on-site evaluation. The mean
concentration of phenol in the effluent
from the biopond system was 0.269
mg/l with a range from 0.031 to 0.449
mg/l. The mean concentration of phenol
in the effluent from the MMF-AC pilot-
scale treatment system was 0.002 mg/l
with a range from <0.001 to 0.004 mg/l.
The biopond system with the large
stabilization basin appearedtobecapable
of absorbing "shock" loads of high
concentrations of organics without
malfunction of the biodegradation capa-
city. Therefore, this system while not cap-
able of achieving the same overall
reductions as the MMF-AC during initial
stages of the test, would appear to be
more reliable for handling the large
fluctuations in concentration of waste
organics. In addition, the biopond required
minimal supervision by refinery personnel.
Ozone Treatment of Sourwater
Stripper Effluent
Samples of the sourwater stripper
effluent were transported to the laboratory
for ozonation. Two tests were performed
at high pressure (100 psig) on effluent
samples collected September 14, 1981,
Run I and Run II. The percent removal of
COD was 73% in Run I and 74% in Run II.
The percent removal of TOC was not as
high, 57% and 56% in Run I and II,
respectively, as COD removals. The ratio
of COD to TOC decreased from 3.21 at
start of run to 2.00 at end. Ammonia
concentration was analyzed in Run II to
determine if ammonia was creating a
chemical oxygen demand. The concen-
tration of ammonia was not significantly
altered by ozone treatment.
Two tests were performed at low
pressure (8 psig) on effluent samples
collected October 8, 1981, Run III and
Run IV. The percent removal of COD was
56% in Run III and 57% in Run IV. As
in Runs I and II, the percent removal of
TOC was less than that for COD, i.e., 35%
in Run III and 46% in Run IV. The ratio of
COD to TOC was also decreased. Phenol
was completely oxidized by the ozone
treatment at the end of 4 hours. The
phenol concentration was monitored at
1-hour intervals in Run IV and revealed
almost complete oxidation of phenol after
2 hours of treatment. No detectable levels
Table 1. Calculated Mean Percent Removal of Contaminants from the SWS Process
Wastewaters by the Fu/l-Scale Biopond and the Pilot-Scale MMF-AC Units
B'opond
MMF-AC
Phenol
99.87
99.99
Sulfide
100
100
Ammonia
24.8
116
BOD
90.1
95.3
TOC
90.9
969
Oil &
Grease
95.5
99.8
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of sulfides were found after ozone
treatment.
The results clearly indicate ozonation
could be used for reduction of COD,
phenol, and sulfides in process waste-
waters. Ozone treatment for 4 hours was
not as effective as activated carbon or the
biopond system in percent removal of
TOC. Extension of time of treatment
would probably improve percent removal
of TOC by ozonation.
Based upon comparisons of percent
removal of degradable organic contami-
nants, the pilot-scale MMF-AC and lab-
scale ozonation unit could be utilized to
treat concentrated process wastewaters
from petroleum refineries. The full-sized
biopond system at Refinery C achieved
equivalent or better efficiencies in
removal of COD, TOC, oil and grease,
phenol, sulfides and ammonia than the
pilot-scale MMF-AC or lab-scale ozonation
unit. No attempt was made to estimate
capital costs of installation or operation
costs of the units evaluated; however, it
would appear that the biopond system
would be more economical than either of
the more advanced types of treatment
systems. The MMF-AC or ozone treatment
units might be more practical for addition
to an existing refinery where space to
install a biopond system was not available.
Characterization of Residuals
from Petroleum Refining
Residuals from selected process units
in four petroleum refineries were analyzed
by the EPA Extraction Procedure to
determine if these waste products
contained sufficient quantities of chemical
contaminants to be classified as hazardous
materials. The EPA Office of Solid Waste
published guidelines defining hazardous
materials based upon properties of
ignitability, corrosivity, reactivity, and
toxicity (Federal Register 45:33084-
33139, May 19, 1980). If the EP extract of
a waste contained concentrations of
contaminants in excess of those listed in
the Federal Register, it would be classified
as hazardous and subject to special
regulations for transport and disposal.
Five specific waste residuals from
petroleum refining were listed as hazard-
ous by the EPA — dissolved air flotation
(DAF), slop oil emulsions, heat exchange,
bundle cleaning sludge, API separator
sludge, and tank bottoms from leaded
gasoline storage. The following were
collected: residuals from API separators
at four refineries and samples of slop oil
emulsion, dissolved air flotation, bottoms
from light oil API separator, solids from a
cooling tower blowdown, and sludges
from an aerated biopond at three refineries.
The results of the herbicide and
chlorinated hydrocarbon pesticide analyses
revealed no cases of the petroleum
refinery residuals which exceeded EPA
criteria. The concentration of mercury in
the petroleum refinery residues analyzed
was below detection limit.
The EP extracts from the oil refinery
residuals were also analyzed for organic
contaminants by extraction with methy-
lene chloride at pH <11 and pH <2 to
obtain a base-neutral and weak acid
fraction, respectively. The base-neutral
fraction was then separated into alipha-
tics, aromatics, and neutral compounds
by silica gel chromatography. The aromatic
fraction was analyzed by GC-MS to
determine specific compounds which
might occur in these residues. The
number of compounds identified in the
aromatic fractions ranged from zero in
the cooling tower residues from Refinery
C to 42 in the Refinery B slop oil
emulsions. The classes of hydrocarbon-
type compounds identified ranged from
simple monocyclic aromatics such as
toluene to complex polynuclear aromatics
such as anthracene/phenanthrene.
Some compounds containing oxygen and
sulfur substitutes were also identified.
The alkylated bicyclic and polycyclic
aromatic compounds were most abundant
in the extracts.
Summary and Conclusions
Phase I
Chemical characterization of selected
process wastewaters from petroleum
refineries indicated that contact waters
from fluid catalytic cracking units, coking
units, barometric condensers, and crude
desalting units were major contributors
of organic contaminants to refinery
wastewaters. At Refinery A, where a
reasonable estimate of wastewater
volumes could be obtained, four process
wastewater streams were responsible for
greater than 60% of the phenol, sulfide,
ammonia, BOD, TOC, and oil and grease
contaminants which occurred in the
combined wastewaters from the entire
refinery. Either elimination of these
process contact wastewaters by installa-
tion of equivalent non-contact units or
intensive treatment of the process
wastewaters would improve overall
effluent quality from the refineries.
Phase II
The percentage removal efficiency of the
full-scale biopond system at Refinery C
for conventional pollutant parameters
such as phenol, sulfide, BOD, TOC, and
oil and grease was greater than 90%.
While not as efficient as the pilot-scale
MMF-AC treatment system during initial
stages, i.e. greater than 95% removal, the
biopond system achieved a better overall
removal efficiency than the pilot-scale
MMF-AC. The adsorption capacity of the
pilot-scale carbon columns for TOC
was exceeded by second day during the
second on-site test. However, break-
through of phenol did not occur until the
16th day of the test. The biopond system
appeared to be comparable to the MMF-
AC system from an overall viewpoint.
Laboratory evaluations of the capability of
ozonation to reduce organic pollutant
loads in concentrated process waste-
waters indicated that greater than 73%
removal of COD could be achieved within
4 hours of treatment at 100 psig. Low-
pressure (8 psig) ozonation achieved
greater than 56% removal of COD within
4 hours of treatment. The on-site scale
and laboratory evaluations showed that
advanced type of treatment systems
could be used to reduce total concentration
of organic pollutants from highly contam-
inated process wastewaters. However,
these systems would not be as practical or
economically feasible as biological
oxidation units.
Phase III
Chemical characterization of EP extracts
from selected petroleum refinery residuals
indicated that the residuals analyzed
would not be classified as "toxic" by
EPA's criteria. Based upon the results of
this project, it would appear that the API
separator residuals, and possibly DAF
and slop oil emulsions, should not be
categorically listed as hazardous wastes
but should be analyzed on a case by case
basis. Admittedly, the number of petroleum
refinery residuals sampled during this
project was too few to permit us to
determine that these residuals are
generally not hazardous. However,
sufficient samples were analyzed to
determine that not all API separator
residuals should be categorically classified
as hazardous. The overall results of the
three phases of this project clearly
indicate the complexity of petroleum
refinery wastewaters and residuals.
Application of the nigh resolution capacity
of capillary chromatography coupled
with the identification capabilities of
mass spectrometry resulted in a bewild-
ering list of specific organic contaminants
identified in the petroleum refinery
process wastewaters. The significance of
some of the compounds identified is
difficult to ascertain, at this time. Perhaps
the most significant finding was the
absence of detectable quantities of
"priority" pollutants in biologically
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treated refinery wastewaters, thus
illustrating the effectiveness of biode-
gradation processes for removal of most
of these hazardous organic contaminants
or at least reduction of concentrations to
non-deleterious levels.
S. L. Burks and J. Wagner are with the Oklahoma State University, Stillwater,
Oklahoma 74078.
Leon H. Myers is the EPA Project Officer (see below).
The complete report, entitled "Characterization and Treatment of Aqueous
Wastes and Residue from Petroleum Refineries," (Order No. PB 83-260 281;
Cost: $14.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Robert S. Kerr Environmental Research Laboratory
U.S. Environmental Protection Agency
Ada, OK 74820
GOVERNMENT PRINTING OFFICE 1983-659-017/7232
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
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