United States
Environmental Protection
Agency
EPA/540/SR-95/516
August 1995
&EPA
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Emerging Technology
Summary
Demonstration of Ambersorb®
563 Adsorbent Technology
A field pilot study was conducted to
demonstrate the technical feasibility
and cost-effectiveness of Ambersorb®
5631 carbonaceous adsorbent for
remediating groundwater contaminated
with volatile organic compounds
(VOCs).
The Ambersorb adsorbent technol-
ogy demonstration consisted of four
service cycles, three steam regenera-
tions, and one superloading. The study
was conducted using a 1-gallon-per-
minute (gpm) continuous pilot system
that consisted of two adsorbent col-
umns configured to operate in parallel
or in series.
During the first service cycle, the col-
umns were operated in parallel for di-
rect comparison of the performance of
virgin Ambersorb 563 adsorbent with
that of virgin Filtrasorb® 4001 granular
activated carbon (GAC). While operat-
ing at five times the flow rate loading,
Ambersorb 563 adsorbent was able to
treat approximately two to five times
the bed volumes (BVs) of water as did
Filtrasorb 400 GAC before VOC break-
through at the maximum contaminant
level (MCL) was observed.
1 Mention of trade names or commercial products does
not constitute endorsement or recommendation for
For the remaining cycles, two
Ambersorb 563 adsorbent columns
were operated in series to investigate
the effect of multiple service cycles and
steam regeneration on Ambersorb ad-
sorbent performance. After each ser-
vice cycle, steam regeneration of the
Ambersorb adsorbent column was per-
formed on-site. The regeneration pro-
cess yielded a condensate consisting
of a separable concentrated organic
layer and a VOC-saturated aqueous
phase. In addition, the principle of
superloading was demonstrated by
passing the aqueous phase from the
third steam regeneration through an
Ambersorb adsorbent superloading col-
umn.
This Emerging Technology Summary
was developed by EPA's National Risk
Management Research Laboratory, Cin-
cinnati, OH, to announce key findings
of the Superfund Innovative Technol-
ogy Evaluation (SITE) Emerging Tech-
nology project that are fully
documented in a separate report of the
same title (see report ordering form in
the back of this document).
Introduction
Roy F. Weston, Inc. (WESTON®) con-
ducted a field demonstration study to
evaluate (Rohm and Haas) Ambersorb 563
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adsorbent technology for remediating
VOC-contaminated groundwater. The
Ambersorb 563 adsorbent technology is
currently commercially available. The
project was conducted under the Emerg-
ing Technology Program of the EPA SITE
program at Site 32/36 at Pease Air Force
Base in Newington, NH, over a 12-wk
period during the spring/summer of 1994.
A slip stream from the influent line to the
two air strippers currently operating at Site
32/36 was used as the groundwater source
for the pilot-scale demonstration. Site 32/
36 was selected for the Ambersorb 563
adsorbent field trial because the ground-
water in this area is contaminated with
vinyl chloride (VC), 1,1-dichloroethene (1,1-
DCE), cis-1,2-dichloroethene (cis-1,2-
DCE), trans-1,2-dichloroethene (trans-
1,2-DCE), and trichloroethene (TCE). Con-
taminant concentrations in the groundwa-
ter ranged from parts per billion (ppb) to
low parts per million (ppm) for TCE.
The objectives of the Ambersorb adsor-
bent technology demonstration project in-
cluded:
• Demonstrate that Ambersorb
adsorbents can offer a cost-effective
alternative to GAC treatment, while
maintaining effluent water quality that
meets drinking water standards.
• Validate design parameters and sys-
tem performance to be used for scale-
up to full-plant scale, including
evaluating different service cycles and
establishing steam regeneration effi-
ciency, superloading, and ease of
phase separation.
• Evaluate the performance/cost char-
acteristics of the Ambersorb 563 ad-
sorbent groundwater remediation
system.
Methodology
The Ambersorb adsorbent technology
demonstration employed a 1-gpm continu-
ous pilot system. The pilot unit included
prefilters to remove suspended solids, two
adsorbent columns that could be oper-
ated in parallel or series, one superloading
column, and a steam regeneration sys-
tem.
The steam regeneration system enabled
the direct on-line regeneration of the
Ambersorb adsorbent columns onsite and
included a steam generator, condenser,
collection/separation vessel, and vapor
phase Ambersorb adsorbent trap for the
condenser vent discharge. Steam was
passed through the beds in a downflow to
minimize condensate holdup in the ves-
sels. To conduct a countercurrent regen-
eration, both adsorbent columns used an
upflow, fixed bed configuration.
The testing program included:
• four service cycles
• three steam regenerations
• one superloading
Superloading refers to the process
whereby the aqueous condensate from
the steam regeneration of an Ambersorb
563 adsorbent service column is treated
using a smaller column containing
Ambersorb 563 adsorbent. Following
superloading treatment, the aqueous con-
densate is discharged as part of the treated
water stream. The superloading process
is not typically used for GAC systems.
A breakthrough capacity computer
model, developed by Rohm and Haas,
predicted the service cycle times for the
demonstration study based on the aver-
age historical contaminant concentrations
measured in the site groundwater. In
addition, it compared the predicted and
measured performance of Ambersorb 563
adsorbent based on the average operat-
ing conditions and influent VOC concen-
trations measured during each service
cycle.
In the first service cycle, the perfor-
mance of Ambersorb 563 adsorbent and
the performance of Filtrasorb 400 GAC
were directly compared. The remaining
service cycles evaluated two Ambersorb
563 adsorbent columns in series. Influent
and effluent samples were collected and
analyzed for VOCs during each cycle to
establish breakthrough curves. Process
parameters, including groundwater influ-
ent flowrate, temperature, and pressure,
were also monitored at periodic intervals
throughout the field trial.
Steam regenerations were conducted
on the Ambersorb adsorbent column at
the end of Cycle 1 and on the lead
Ambersorb adsorbent columns at the end
of Cycles 2 and 3 to evaluate the effect
steam regeneration had on Ambersorb
adsorbent performance. The steam re-
generations were also conducted at vari-
ous temperatures (307 °F, 293 °F, 280 °F)
to evaluate the effect of regeneration tem-
perature on contaminant recovery. The
regeneration process yielded a conden-
sate stream consisting of a distinct sepa-
rable organic layer and an aqueous phase.
Organic and aqueous phase samples and
the vapor trap adsorbent were collected
and analyzed for VOCs to assess regen-
eration recovery.
A superloading test to treat the aque-
ous condensate from a typical Ambersorb
563 adsorbent column steam regenera-
tion process was also conducted during
the field trial. To demonstrate the con-
cept of a closed loop system in which the
only discharge is the separable organic
layer, a small dedicated superloading col-
umn treated the aqueous condensate from
the third steam regeneration. The
superloading column used Ambersorb ad-
sorbent because of its high adsorption
capacity and superior kinetics while oper-
ating at a high flow rate loading. Influent
and effluent samples were collected and
analyzed for VOCs to evaluate
superloading performance.
Results and Discussion
Influent Groundwater
VC, cis-1,2-DCE, trans-1,2-DCE, and
TCE were present in the influent ground-
water at concentrations exceeding the MCL
established in the National Revised Pri-
mary Drinking Water Regulations. TCE
was the contaminant measured at the high-
est average concentration in the influent
stream, ranging between 3,600 |ig/L and
4,510 ng/L Because of the high TCE
concentrations in the influent stream, in-
fluent samples required at least a 10-fold
dilution before analysis, thus increasing
the minimum levels of detection for each
VOC. As a result, VC and 1,1-DCE,
present in the influent stream at low ppb
levels (less than 5 |ig/L), could not be
accurately quantified for certain service
cycles. Therefore, because of these ana-
lytical limitations, influent VC and/or 1,1-
DCE concentrations were estimated for
certain service cycles based on the amount
of the contaminant subsequently recov-
ered during regeneration.
Service Cycles
Virgin Ambersorb 563 adsorbent perfor-
mance and virgin Filtrasorb 400 GAC per-
formance are compared in Table 1.
Ambersorb 563 adsorbent and Filtrasorb
400 GAC VC and TCE breakthrough
curves are compared in Figure 1. Cycle 1
performance results show that both
Ambersorb 563 adsorbent and Filtrasorb
400 GAC achieved water quality below
the MCL for each VOC. Based on the
number of BVs treated to the MCL, the
results show that Ambersorb 563 adsor-
bent was able to treat approximately two
to five times the BVs of water as Filtrasorb
400 GAC while operating at five times the
flow rate loading [1/5 the empty bed con-
tact time (EBCT)].
Performance results for the four service
cycles are summarized in Table 2. A
preload volume of 4,000 BVs was added
to the total BVs treated to the MCL for
Cycles 3 and 4 to account for the BVs of
lead column leakage treated during the
previous service cycles (i.e., when the col-
umn was in the lag position).
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Table 1. Comparison ofAmbersorb 563 Adsorbent and Filtrasorb 400 GAC Performance Results (Cycle 1)
BVs Treated to MCL
Volatile Organic Compound
Vinyl chloride
1, 1-Dichloroethene
cis- 1,2-Dichloroethene
trans- 1,2-Dicloroethene
Trichloroethene
MCL'
(W/L)
2
7
70
100
5
Ambersorb 563
Adsorbent
8,120
> 13, 700
9,600
> 13, 700
8,190
Filtrasorb 400
GAC
1,730
>5,070
3,710
5,040
4,850
Difference
Factor^
4.7
-2.7
2.6
>2.7
7.7
Maximum contaminant levels from National Revised Drinking Water Regulations, 40 CFR 141.61.
Difference Factor=(BV Treated by Ambersorb 563 Adsorbent)/(BV Treated by Filtrasorb 400 GAC).
Figure 1. Comparison ofAmbersorb 563 Adsorbent and Filtrasorb 400 GAC VC and TCE breakthrough curves.
Table 2. Summary ofAmbersorb 563 Adsorbent Performance Results
MCL
BVs Treated to MCL
Cycle 1
Cycle 3t
Change'
BVs Treated to MCL
Cycle 2
Cycle 4t
Change'
Column I.D.
Column Condition
A563A
Virgin
A563A-1
Regenerated
A563B
Virgin
A563B-1
Regenerated
Volatile Organic Compound:
Vinyl chloride
1, 1-Dichloroethene
cis- 1,2-Dichloroethene
trans- 1,2-Dichloroethene
Trichloroethene
Influent VC cone., [ig/L
2
7
70
100
5
8,120
> 13,700
9,690
.13,700
8,190
3.4§
5,130
> 12,600
8,810
.12,600
5,160
5.7
-37
~-8
-9
-8
-37
8,320
> 12,700
10,600
> 12, 700
9,400
4.9
5,010
16,600
11,140
>16,800
7,350
10.1#
-40
>31
5
-32
-22
Maximum contaminant levels from National Revised Drinking Water Regulations, 40 CFR 141.61.
t Change = (performance of virgin adsorbent - performance after first steam regeneration)/(performance of virgin adsorbent) '
t Includes BVs preloaded during previous cycle.
§ VC concentration estimated based on the mass recovery results for the first steam regeneration of column A563A.
# VC concentration estimated based on reanalysis of selected influent samples at lower dilution.
100
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Performance results show there was a
37% to 40% decrease in BVs treated to
the VC MCL and a 22% to 37% decrease
in BVs treated to the TCE MCL after steam
regeneration of Ambersorb 563 adsorbent.
For the remaining VOCs, however, there
was no consistent decrease in the capac-
ity of Ambersorb 563 adsorbent after steam
regeneration, based on BVs treated to the
MCL.
The reduction in BVs treated to the VC
and TCE MCL is partially attributed to the
increase in influent VC concentration dur-
ing the study. Influent VC concentrations
almost doubled between each steam re-
generation cycle.
After the first regeneration, the adsorp-
tion capacity for most adsorbents, includ-
ing GAC, will be reduced. Additional steam
regenerations and service cycles are
needed to determine the long-term effect
of multiple steam regenerations on
Ambersorb 563 adsorbent performance.
A comparison of the performance of
Ambersorb 563 adsorbent measured dur-
ing the field demonstration to that pre-
dicted by the Rohm and Haas
breakthrough capacity model indicated that
the model is a useful tool in predicting
adsorbent capacities and service cycle
times. The study showed the importance
of having accurate analyses for VC, 1,1-
DCE, and other less strongly adsorbed
contaminants as input to the model.
Steam Regenerations
Total VOC mass recovery results for
the steam regenerations are summarized
in Table 3. The steam regeneration re-
sults show that a significant recovery of
the VOC mass loaded onto the Ambersorb
adsorbent columns during the service
cycles, ranging from 73% to 87%, was
achieved. The results also show that the
bulk of the VOC mass recovery occurred
within the first 3 BVs of steam as conden-
sate. Furthermore, the results indicate
that approximately 88% to 93% of the
VOC mass recovered was associated with
the easily separable organic phase.
The incomplete mass recovery of VOCs
may be due to the following:
• Volatilization of VOCs during sam-
pling of the condensate aqueous and
organic phases.
• Inaccuracies during analysis of the
steam regeneration samples.
• VOCs retained in the highest energy
micropores of the Ambersorb adsor-
bent not being removed during steam
regeneration.
• Dehydrohalogenation of the chlori-
nated organics.
Table 3. Summary of Steam Regenerations Total VOC Mass Recovery Results
Steam regeneration
Regeneration 1 Regeneration 2 Regeneration 3
Column temperature, 'F 307
Total BVs generated 7.6
Total VOC mass recovery @ 3 BV, % 73.2
Total VOC mass recovery @ End, % 78.0
Total VOC fraction in organic phase @ End, % 89.5
293
7.0
70.7
73.4
92.5
280
8.9
79.1
87.2
88.4
Superloading
The results of the superloading test in-
dicate that the aqueous condensate gen-
erated during steam regeneration was
effectively treated to levels below the MCL.
A total of 14 BVs of condensate, which
averaged 700,000 ng/L VOCs (predomi-
nately TCE), were passed through the
superloading column. TCE was the only
VOC detected in the effluent stream and
was first detected at a concentration of
2.5 |ig/L after 14 BVs had been treated.
Scale-Up Parameters
The information developed during the
demonstration study enhanced the exist-
ing database for the Ambersorb 563 ad-
sorbent technology and helped validate
process design parameters and system
performance for scale-up to full-scale treat-
ment systems. The key process operat-
ing parameters for the preliminary
engineering design of an Ambersorb 563
adsorbent system are:
• process configuration
• EBCT or flow-rate loading
• vessel configuration
• steam regeneration conditions
A full and accurate characterization of
the contaminants in the influent, as well
as the effluent discharge limitations, is
important input for the Ambersorb adsor-
bent system design especially for predict-
ing service cycle time. The Emerging
Technology Report discusses typical val-
ues for full-scale design parameters to be
used for preliminary purposes only. De-
sign parameters for a full-scale system
must be specifically derived for each treat-
ment application.
Conceptual Design and
Preliminary Cost Estimate
The results of the Ambersorb adsorbent
demonstration study were used to develop
conceptual designs and cost estimates for
full-scale treatment systems (average de-
sign flow of 100 gpm) using Ambersorb
563 adsorbent and GAC. Full-scale de-
sign parameters were based on the influ-
ent groundwater characteristics and
adsorbent performance results measured
during the first service cycle. The dis-
charge criteria for the effluent from the
treatment systems were assumed to be
drinking water standards (i.e., MCL).
The Ambersorb 563 adsorbent system
is designed as an up-flow, fixed-bed sys-
tem, with two 660-lb adsorbent beds in
series, each having a 1.5-min EBCT at
100 gpm. In addition, the Ambersorb 563
adsorbent system includes on-line steam
regeneration and a condensate treatment
superloading system. The lead Ambersorb
adsorbent bed is regenerated approxi-
mately every 8 days or 8,000 BVs.
The GAC adsorbent system is designed
with four 1,800-lb adsorbent beds (two
parallel systems of two GAC beds in se-
ries). Each GAC bed has a 9.6-min EBCT
at 50 gpm. In addition, the GAC system
uses commercially available transportable
GAC units that are replaced approximately
every 11 days or 1,600 BVs.
Based on the results of the cost analy-
sis, the installed costs (including engineer-
ing design costs) of the Ambersorb 563
adsorbent treatment system ($526,100) are
significantly greater than the installed costs
of the GAC treatment system ($336,800).
The annual operating costs of the
Ambersorb 563 adsorbent system (ap-
proximately $32,500/yr for the first 5 yr),
however, were significantly lower than the
GAC system (approximately $125,800/yr
for the first 5 yr).
The total present worth cost analysis of
the Ambersorb 563 adsorbent and GAC
treatment systems indicates that, after ap-
proximately 2 yr, the total present worth
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cost of the Ambersorb 563 adsorbent treat-
ment system is less than the GAC treat-
ment system. The reduced costs over
time result from the significantly lower op-
erating costs for the Ambersorb 563 ad-
sorbent system when compared with the
GAC system.
Conclusions
Based on the results of the Ambersorb
563 adsorbent technology demonstration,
the following conclusions were developed:
1. Ambersorb 563 adsorbent is an ef-
fective technology for the treatment
of groundwater contaminated with
chlorinated organics. The effluent
groundwater from the Ambersorb 563
adsorbent system consistently met
drinking water standards.
2. Direct comparison of the performance
of Ambersorb 563 adsorbent with
Filtrasorb 400 GAC, based on the
number of BVs treated to the MCL,
indicated that Ambersorb 563 adsor-
bent was able to treat approximately
two to five times the BVs of water as
did Filtrasorb 400 GAC while operat-
ing at five times the flow rate loading
(1/5 the EBCT).
3. During the demonstration, on-site
steam regeneration was successful
and yielded an easily separable con-
densate consisting of a VOC-satu-
rated aqueous stream (top layer) and
a concentrated organic phase (bot-
tom layer). The steam regenerations
recovered approximately 73% to 87%
of the total VOC mass adsorbed on
the Ambersorb 563 adsorbent column
during the service cycle. The organic
phase contained approximately 88%
to 93% of the total VOC mass recov-
ered. The majority of VOC recovery
occurred within 3 BVs of steam as
condensate.
4. The principle of superloading was
demonstrated as an effective treat-
ment method for the aqueous con-
densate layer resulting from the steam
regeneration of the Ambersorb ad-
sorbent. A condensate stream con-
taining 700,000 ng/L VOCs was
treated to levels below the MCL us-
ing a superloading column containing
Ambersorb 563 adsorbent.
5. Preliminary cost estimates of the in-
stalled costs for a 100-gpm treatment
system using Ambersorb 563 adsor-
bent were significantly greater than
those using GAC. The annual oper-
ating cost of the Ambersorb 563 ad-
sorbent system, however, was
significantly lower than the GAC sys-
tem. The total present worth cost
analysis showed that after approxi-
mately 2 yr, the Ambersorb 563 ad-
sorbent system would be more
economical because of its lower op-
erating costs.
6. The demonstration study enhanced
the existing database for the
Ambersorb 563 adsorbent technology
and helped validate process design
parameters and system performance
for scale-up to full-scale treatment sys-
tems. Information pertaining to key
parameters of process configuration,
EBCT or flow rate loading, vessel con-
figuration, and steam regeneration
conditions was developed or con-
firmed as part of the demonstration
project.
7. Based on a comparison of the mea-
sured performance results obtained
during the demonstration project and
the performance results predicted by
the breakthrough capacity model de-
veloped by Rohm and Haas, the
breakthrough capacity model is a use-
ful tool in predicting the adsorption
capacity and service cycle times to
support full-scale system design and
cost analysis for the Ambersorb 563
adsorbent technology.
8. The accurate quantification of VC in
the influent groundwater is critical in
establishing the service cycle time for
process operations of the Ambersorb
adsorbent and GAC treatment sys-
tems. Based on the Rohm and Haas
predictive model, ppb levels of VC in
the groundwater result in significant
decreases in adsorbent performance
when compared with groundwater
containing no VC. As measured in
the study and predicted by the model,
incremental increases in VC concen-
tration result in decreases in adsorp-
tion capacity.
9. A decrease in the number of BVs
treated to the MCL was observed for
certain contaminants following one
steam regeneration of the virgin
Ambersorb 563 adsorbent. The re-
duction in BVs treated to the MCL
may be the result of the increase in
influent VC concentration during the
study. Additional steam regenerations
and service cycles are required to
estimate the effect of steam regen-
eration on the long-term performance
of Ambersorb 563 adsorbent.
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Russell I/I/ Frye, Joseph F. Martina, and Anthony G. Bove are with Roy F.
Weston, Inc., West Chester, PA 19380-1499.
Ronald J. Turner is the EPA Project Officer (see below).
The complete report, entitled "Demonstration ofAmbersorb's 563 Adsorbent
Technology," (Order No. PB95-264164; Cost: $27.00, 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:
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection Agency
National Risk Management Research Laboratory (G-72)
Cincinnati, OH 45268
Official Business
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