United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-81-129 Sept. 1981
Project Summary
Laboratory Studies of
Priority Pollutant Treatability
James K. Smith, Robert J. Planchet/E. Jasper Westbrook, and Frederick J. Zak
This report describes a screening
investigation of several methods
currently available for removal of
priority pollutants from industrial
plant waste waters. A sample from an
actual industrial stream was used for
laboratory bench scale treatment tests
on five priority pollutants present at
significant concentrations. Results
are of interest in evaluating best
available technology for removal of
priority pollutants and will be helpful
to those planning further research
including demonstration units for
treating similar wastes.
The study focused on carbon ad-
sorption, resin adsorption and steam
stripping technologies and developed
order-of-magnitude cost relationships
for each technology. The results of the
study indicate high removal efficiency
for the priority pollutants nitroben-
zene, p-dichlorobenzene, chloroben-
zene, phenol and dinitrotoluene by
both carbon adsorption and resin
adsorption. Steam stripping was not
effective under the test conditions for
removal of phenol or dinitrotoluene.
The steam stripping data also indicated
that removal of the non-conventional
pollutant aniline was ineffective.
Operating costs for treating streams
similar to the stream tested are
estimated to be in the order of $2 to $3
per 1000 liters (265 gallons) for flows
of about 1130 liters per minute (300
gallons per minute). Cost effective-
ness may favor use of carbon adsorp-
tion over resin adsorption and combi-
nation systems appear to offer no
economic advantage at pollutant
levels present in the sample.
This Project Summary was devel-
oped by EPA's Industrial Environ-
mental Research Laboratory, Cincin-
nati. OH, 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
A wastewater grab sample was taken
from a typical medium sized petrochem-
ical manufacturing complex which met
study criteria for (a) the presence of at
least five priority pollutants, (b) a multi-
product manufacturing operation, (c) a
demonstrated toxicity of the waste and
(d) lack of a specific treatment back-
ground. Concentrations of the tested
priority pollutants were obtained from
gas chromatograph/mass spectrometry
(GC/MS) and gas chromatography (GC)
analyses.
An earlier literature search (1) had
indicated carbon adsorption, resin
adsorption and steam stripping as
potential treatment methods. These
technologies were evaluated for effec-
tiveness using laboratory bench scale
tests on the wastewater sample. Studies,
based on results of the bench scale
tests, demonstrate potentially achiev-
able degrees of removal and allow
estimation of order of magnitude
removal costs utilizing the three treat-
ment methods.
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10O.O -,
I
c
cts
o
CJ.
I
u
to
*
§
1
70.0-
7.0-
S51 Carbon, pH 9
70
700 7000
Concentration (ppb)
WOOD
10000O
Figure 1. Activated carbon isotherm studies - priority pollutant reduction from an industrial waste stream.
Applicable Technologies
Application of carbon adsorption as a
treatment technique requires the col-
lection and evaluation of laboratory and
pilot plant data from which realistic
engineering design decisions can be
made.
The suitability of a particular carbon is
first indicated by batch equilibrium
(isotherm) evaluations of adsorptive
capacity as a function of residual
pollutant concentration, as shown for
the sample in Figure 1. However,
dynamic test data are required to
provide a basis for equipment design.
Such dynamic data can be scaled up to
develop equipment requirements for
plant size operations and costs for the
adsorption and regeneration systems.
For the purpose of this study, equi-
librium isotherms were developed for
two carbons at three pH conditions.
Dynamic tests, in a three column pilot
plant were performed on one of the two
carbons, at pH 9 and through five
successive carbon regenerations.
Resin adsorption, like carbon adsorp-
tion, requires fundamental laboratory
data and suitability is first indicated by
isotherm studies (Figure 2). Potential
7000 -a
o
•s
to
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advantages of resin adsorption include
(a) adsorptive selectivity through resin
choice, (b) possible recovery of pollutant
materials, (c) low energy consumption
and (d) durability of the resin matrix.
Adsorption of polymeric resins is
normally carried out in fixed beds which
require periodic regeneration to main-
tain adsorptive capacity. Cited com-
mercial applications (2) point to useful
resin life exceeding several hundred
cycles over a period of years.
Steam stripping relies on the combi-
nation of volatility and relatively low
solubility of each organic pollutant.
Design of stripping systems often can be
accomplished without laboratory eval-
uation since rigorous calculations
based on thermodynamic data may
satisfactorily simulate performance.
The economics of steam stripping are
particularly sensitive to amount and
cost of steam or other energy sources
used for heating the water to be treated
and for providing stripping vapor flow.
Experimental Procedures
Initial qualitative and quantitative
data on the wastewater sample received
were obtained employing EPA's priority
pollutant GC/MS procedures wherein
an internal standard of dio - anthracene
is used to provide a basis for both
relative retention time measurements
and semi-quantitative mass spectro-
metric analysis. Based on the GC/MS
quantitative analysis, five priority
pollutants (chlorobenzene, p-dichloro-
benzene, nitrobenzene, dinitrotoluene
and phenol) were selected for study in
the test program. For routine quantitative
analysis, during the tests the simpler
gas chromatography with flame ioniza-
tion detection was employed. Total
organic carbon (TOC) analysis was also
employed to continuously monitor organ-
ic removal during the dynamic test
program.
The activated carbon equilibrium
studies were performed in a batch mode
by exposing a fixed volume of the test
waste stream to five carbon dosages for
each of the two carbons selected for
evaluation. A volume of 100 ml was
mixed with 0.1, 0.5, 1.0, 5.0 and 10.5
grams of activated carbon and the
batches sealed and then agitated for 18
hours. After allowing the carbon to
settle, samples were withdrawn from
the aqueous phase, filtered and analyzed
for TOC content and for concentration of
individual priority pollutants.
The equilibrium studies were followed
by dynamic studies in which a series of
three continuous-flow adsorption runs
were performed. Carbon regeneration
studies (up to five carbon regenerations
during each series) were performed at
various regeneration temperatures.
In order to analyze resin effectiveness,
a registered trademark item, Amberlite
XAD-4 manufactured by Rohm & Haas,
was selected for evaluation. The pore
size of the resin selected allows for
smaller molecules such as single ring
aromatics to migrate easily to active
surface points. Substantially larger
molecules are excluded. Prior to dynamic
testing, an equilibrium isotherm study
was performed in a batch mode similar
to the one used for carbon adsorption.
The dynamic studies with resin regen-
eration by methanol were performed in
a series of six runs. Time-history-
related samples were collected and
analyzed.
The feasibility of steam stripping the
organic priority pollutants was investi-
gated by running batch and continuously
operated bench-scale stripping columns.
Experimental Results
Analysis of the untreated industrial
waste stream was reported during the
course of the five month test program.
These tests indicated a minimal change
of composition with time. The sample
was stored at 4°C and at a pH of
approximately 9. The compounds of
interest were all present at concentra-
tions greater than 1 ppb.
The data indicate that carbon removal
capacity is pH sensitive and that
dinitrotoluene exhibits poor adsorption
at low concentrations (see Figure 1).
Regeneration was conducted at several
temperatures up to 800° F and carbon
regenerated at 800° F demonstrated
that greater adsorption capacity can be
maintained through higher regeneration
temperatures. The amount of carbon
required to treat a given volume of
waste to specific concentration levels
was determined for each pollutant from
breakthrough data based on a fixed
amount of carbon in the test columns. A
typical breakthrough curve for TOC is
shown in Figure 3.
Resin isotherm data indicate dinitro-
toluene is not adsorbed well as concen-
tration decreases (see Figure 2). Results
of the dynamic resin study indicate that
phenol and dichlorobenzene break-
through occurs early in a continuous
column effluent. A typical resin break-
through curve for TOC is shown in
Figure 4.
The results of steam stripping tests
indicated varying degrees of removal for
g.
^ 284-
Q>
3
Uj
2/3-
I 142-
\
o
Cj
Cj
s
71-
o I Column A Effluent
Column C
Effluent
Legend:
oRun 1
a Run 2
' Note: All columns
not sampled for all runs.
Figure 3.
5 JO 15 20 25
Volume Processed (Liters!
Adsorption performance of virgin S-51 carbon.
3
30
35
-------
ki
C
.3
O
.c
c
8.8
36
166
1.329
31
7.9
421
4.1
13
5.0
1,050
29
6.9
367
8,950
44.400
307,000
531,000
3,430
1,900
103,000
4.7
23
161
279
1.8
1.0
54
2
21
15
1.271
31
6
356
22.800
50.500
507,000
195,000
673
6.530
218.000
6.7
15
151
58
0.2
1.9
65
Trace
Trace
31
1.260
31
0.4
349
26,800
111,000
416,000
209,000
457
22,900
218,000
8.8
36
135
68
0.15
7.5
71
a Basis: Calculation Made to Predict Laboratory Results.
b Parts Per Million.
c Parts Per Million Parts Feed.
" Estimated, from TOC Measurements.
e Adjusted to close material balance relative to feed and bottoms. G.C. at'high concentrations judged least reliable.
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Table 2. Treatment Costs
Carbon
Adsorption
Investment
Treatment Costs/Year
Materials
Processing
Total Treatment
Cost Per WOO liter
$1,775,000
537,500
877,000
1,414,500
2.38
Resin
Adsorption
$1,700,000
475,000
1,226,000
1,701,000
2.86
Steam
Stripping
$1,000,000
1 1 1,000
963,000
1,074,000
1.80
ment, with either carbon or resin
adsorption is not cost effective for the
pollutant levels studied.
Treatment costs developed by this
study should be compared to production
volumes of manufactured products
contributing to the pollutants to test the
effect of such treatment systems on
product costs.
References:
1. U.S. Environmental Protection
Agency, Priority Pollutant Treatability
Review (Contract 68-03-2579), July
1978.
2. Fox, C.R., "Plant Uses Prove Recov-
ery with Resins," Hydrocarbon
Process, November, 1978.
James K. Smith, Robert J. Planchet, E. Jasper Westbrook, and Frederick J. Zak
are with Walk, Haydel & Associates, Inc., New Orleans, LA 70130.
Kenneth A. Dostal and David P. Watkins are the EPA Project Officers (see
below).
The complete report, entitled "Laboratory Studies of Priority Pollutant Treat-
ability," (Order No. PB 81-231 235; Cost: $12.50, 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 Officers can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
b -ft U S GOVERNMENT PRINTING OFFICE, 1981 — 757-012/7321
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