United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati, OH 45268
Research and Development
EPA-600/S2-84-029 Mar. 1984
&ER& Project Summary
Removal of Organic
Contaminants from the Drinking
Water Supply at Glen Cove, N.Y.
Dominick D. Ruggiero and Walter A. Feige
A pilot plant research program was
conducted in three phases to examine
treatment alternatives for removing
organic contaminants from ground
water. The treatment methods evaluated
included several approaches to aeration,
resin adsorption, and a combination of
both aeration and resin adsorption.
These processes were evaluated for
their ability to remove trichloroethylene,
tetrachloroethylene, cis-1,2-dichloro-
ethylene. and 1,1,1-trichloroethane.
Also examined was the feasibility of
regenerating granular activated carbon
(GAC) with steam.
Aeration studies determined the
ability of various aeration designs to
remove volatile organic contaminants.
The relative efficiencies of five aeration
methods were evaluated during the
three phases of this research program:
Diffused aeration (both packed and
unpacked column), induced-draft cool-
ing tower, air-lift pumping, induced-air
spray aeration (both packed and unpacked
column), and packed-column air strip-
ping. Air-to-water ratios (A/W) were
varied for each system tested.
The resin used was Rohm and Haas'
Ambersorb® XE-340.* Evaluations
were made of the effects of bed depth,
direction of flow application, hydraulic
loading, length of service time, and the
feasibility of regeneration with steam.
Flows of 1, 2, and 5 mgd (3,785,
7,575 and 18,925 mVday) were
chosen to obtain a range of costs for a
•Mention of trade names or commercial products
does not constitute endorsement or recommendation
for use.
full-scale installation of the systems or
methods determined practicable for the
treatment of ground water from results
observed during this research program.
This final report contains a discussion
of the Phase III pilot plant program and
a summary of the results from the three
phases.
This Project Summary was developed
by EPA's Municipal Environmental
Research Laboratory, Cincinnati, OH,
to announce the 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 city of Glen Cove, NY, experienced
a water shortage in 1977 when several of
its supply wells were closed because of
volatile organic contaminants present at
levels above the New York State guidelines.
To regain a sufficient water supply and
protect the remaining wells, the City
retained a consulting engineering firm to
study two treatment techniques —
adsorption by synthetic resin and stripping
of contaminants by aeration. The Phase I
pilot plant study (March 1979 to January
1980) indicated that resin adsorption
could lower the contaminant levels below
1 /ug/L and that aeration systems, with
proper air-to-water ratios, could reduce
contamination below present New York
State guidelines. These promising results
warranted the continuation of this
project, and EPA funded Phase II of the
study (May 1980 to January 1981) and
later Phase III (October 1981 to January
1983). The project developed design
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parameters and capital and operating
costs for most of the methods evaluated.
Pilot Plant Facilities
The test site for all study phases was
Carney Street, where the highest levels
of well water contaminants were found.
The pilot plant equipment for each phase
was similar, with certain special equip-
ment added to complete the objectives of
each phase.
The equipment for Phase I consisted of
four 6-ft-high (1.83 m), 4-in.-diameter
(0.1 m) Pyrex glass columns each
containing a different depth of XE-340
resin, a 30-in.-diameter (0.76 m) Plexiglas
column for the diffused aeration testing, a
blower to supply air to the diffused
aeration column, an electric steam
generator for regenerating the resin, and
a complete gas chromatograph system to
perform the required onsite chemical
analyses.
Based on the results of Phase I, various
modifications were made to the pilot
plant equipment before Phase II began.
The major modifications were a change in
the size of the resin columns (reduced in
height to 2.2 ft, or 0.67 m), a larger steam
generator, insulation and electric heat-
ing of steam piping and columns during
regeneration periods, and the installation
of a packed, diffused aeration column and
a small cooling tower for air stripping
evaluation. In addition, two of the 6-ft
(1.83-m) Pyrex glass columns were
installed to test the feasibility of regener-
ating granular activated carbon with
steam.
Major additions and modifications to
pilot plant equipment were also made
before Phase III began, based on the
results of the first two phases. These
changes included conversion of one
aeration column to evaluate spray aeration
with induced air, the purchase of a fan for
use with this column, the installation of
an air-lift pump, the addition of a new
blower and several columns, and the
modification of a 6-ft (1,83-m) Pyrex glass
column to allow sampling at 1 -ft intervals
through a granular activated carbon bed.
These additions and modfications required
a change in the basic layout of the pilot
plant facilities. The blowers and aeration
columns were moved away from the
building so that the continuous operation
of the diffused aeration system would not
disturb the building's inhabitants. The
blowers were placed in a shed on a
concrete slab installed to support them
and the aeration columns.
The air-lift pump was installed in Well
No. 20 so that Well No. 22 could be used
to supply the other testing systems.
Results
Adsorption Studies with XE-
340 Resin
Resin adsorption studies carried out
during Phase I compared the effects of
various resin bed depths on contaminant
breakthrough and exhaustion service
times. For the 1 - and 2-ft (0.30-and0.61-
m) columns, breakthrough and exhaustion
were proportional to resin bed depth.
Though effluent contaminant levels were
lower, the exhaustion of the 4-ft (1.22-m)
column was not proportional to bed depth
and service time required for breakthrough.
The Phase I evaluation indicated that
Ambersorb® XE-340 was most effective
in adsorbing tetrachloroethylene, and
slightly better at adsorbing trichloroethylene
than cis-1,2-dichloroethylene.
During Phase II, adsorption studies were
performed at a constant amount and
depth of resin (2 ft, or 0.61 m) and an
application rate of 4 gpm/ft3 (0.42
Lpm/m3) of adsorbent. Comparisons
were made of the upward and downward
flow application modes as well as the use
of virgin and regenerated resins. The
results show that downflow operation
resulted in the lowest contaminant levels
and that virgin resins in the same mode of
operation performed slightly better than
the regenerated resin.
Separate resin and aeration testing
conducted during Phases I and II indicated
that a system combining the two unit
processes might be desirable for organic
contaminant removal. Phase III studied
the best and most economical mix of
aeration and resin to achieve desirable
water quality. Testing included determin-
ation of the maximum hydraulic loading
that could be applied to the resin.
Two resin adsorption systems (one
receiving unaerated well water and the
other receiving pre-aerated well water)
were evaluated during Phase III. Applica-
tion rates of 2, 4, 6, and 8 gpm/ft (0.21,
0.42, 0.63 and 0.84 Lpm/m3) were used
in the system evaluating direct treatment
of the raw well water, and rates of 4,6, and
8 gpm/ft3 (0.42, 0.63 and 0.84 Lpm/m3)
were used in the treatment approach
combining aeration and adsorption.
Resin saturation and exhaustion had a
direct relationship to the applied hydraulic
loading in both treatment system approaches.
For air-to-water ratios of 8:1 and 15:1,
resin service was about five times longer
for the pre-aerated well water than for
the unaerated well water.
Initial regenerations during Phase I
were done using a steam flow concurrent
with that of the water flow. During these
regenerations, cis-1,2-dichloroethylene ^
was steam-stripped from the resin more m
readily than were the other major
contaminants. Contaminant adsorption
onto vacant sites in the lower portion of
the resin bed was probably occurring
because the steam and operational water
flow were in the same direction. For this
reason, countercurrent steam regenera-
tion was attempted.
Improvements to enhance the degree
of regeneration resulted in more success-
ful regenerations in Phase II. High
concentrations of organics stripped from
the resin produced a phase separation
between this layer and the aqueous
steam condensate. The percent of regen-
eration (or the percent of organics removed
after being loaded on the media) was
used as a measure of regeneration
success. Though this measure was only
an approximation, it indicated a high
degree of success for Phase II regenera-
tions. The steam rate used in Phase II was
one bed volume per hour.
Superloading, which is the practice of
introducing the condensate from one
regeneration cycle into the column to be
regenerated next, was performed in
Phase II as a potential solution to the
problem of condensate disposal. Testing
confirmed the belief that superloading
would further concentrate the organics 4
and yield a larger organic phase. "
Granular Activated Carbon
Steam Regeneration Studies
The feasibility of regenerating spent
granular activated carbon with steam
was also examined. Because the tests
use a hydraulic loading that wastwicethe
manufacturer's recommendation to load
the carbon in as short a time as possible,
no attempt was made to evaluated the
adsorption results of the activated carbon
or compare them with those of the resin.
Regeneration of activated carbon with
steam took place twice for each of two
GAC's using the equipment sized for the
regeneration of resin in Phase II. No
special considerations were given to the
carbon. The maximum steam flow avail-
able was used to regenerate the carbons
over a 24-hr period. No attempt was
made, however, to achieve zero contami-
nants in the steam condensate.
Several steam regenerations were
conducted and showed low regeneration
efficiencies compared with the resin.
Mass balances indicated that only 25% to
35% of the organics were stripped from
the carbons. In addition, the effluent from
the regenerated carbon columns exhibited
breakthrough contaminant concentrations M
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in approximately half the service time of
virgin resin or the previous carbon run.
Aeration Studies
Diffused Aeration Studies
The diffused aeration method was the
only approach tested during all three
phases. Testing in Phase I was performed
using a 30-in.-diameter (0.76 m), 10-ft-
high (3.05 m) column with air-to-water
ratios of 30:1, 20:1, 15:1, and 5:1.
The results showed that diffused aera-
tion at air-to-water ratios of at least
15:1 would meet the current New York
State guidelines of 50//g/L per contami-
nant and 100 /ug/L for all organic con-
taminants.
The diffused aeration studies in Phase
II included the same diffused aeration
column used in Phase I and a new
identical column with packing so that the
principle of packed-column diffused
aeration could be evaluated. Both systems
were tested at air-to-water ratios of 15:1,
10:1, and 5:1. During the last stages of
Phase II, the packing from the second
column was removed, and the two
columns were operated in series as
diffused aeration columns. The results of
the diffused aeration testing in Phase II
confirmed the results of Phase I — that
the diffused aeration system could meet
present New York State guidelines at air-
to-water ratios of 15:1 or higher. The two-
stage diffused aeration testing (which
was mainly run to determine a mass
transfer coefficient for diffused aeration)
indicated that second-stage diffused
aeration continues the air stripping
process and improves the effluent water
quality.
In general, the overall removal of
contaminants for the diffused aeration
column was 84% at an air-to-water ratio
of 15:1. This removal efficiency was
improved to an overall average 90% by
the two-stage aeration. The packed
column diffused aeration system showed
an overall removal of 83% using a 10:1
air-to-water ratio.
The performance of the diffused
aeration column was monitored during
Phase III as a part of the combined
aeration-adsorption evaluation. Results
were similar to those obtained during
Phases I and II.
Induced-Air Spray Aeration
Studies
The induced-air spray aeration system
tested during Phase III used the column
from Phase II for the packed-column
diffused aeration study. This column was
modified so that ambient air could be
drawn near its base by a fan mounted on
the top of the column. The initial
approach was to study several spray
systems using nozzles. As the testing
proceeded, packing was added to the
column. Air-to-water ratios between
450:1 and 12,000:1 and natural draft
conditions (fan not operating) were used
during the Phase III testing. Results of the
induced-air spray aeration studies indi-
cated that removals between 50% and
75% were achievable with spray nozzles.
When packing was added to the column,
overall removal of contaminants exceeded
90% and met present New York State
guidelines. The natural draft approach
was examined with and without packing
and resulted in greater than 80% and
43% to 63% removals, respectively.
Packed-Column Air Stripping
Studies
During Phase III, an EPA-designed,
packed-column air stripper was operated
at the Glen Cove site. The column
contained 18 ft (5.5 m) of packing
material and both 1- and 2-in. (2.5- and
5.0-cm) plastic saddles were independent-
ly used as packing. Air was drawn up
through the column using the suction
side of a low-pressure blower. During the
two evaluation periods, several air-to-
water ratios ranging from 5:1 to 85:1
were tested. The overall contaminant
removals ranged from about 63% to
greater than 95%.
Air-lift Pumping Studies
A field-fabricated air-lift pump was
installed during Phase III. The air-to-
water ratio was varied by increasing or
decreasing either the length of the air
pipe in the well or the volume of air
supplied to the well by the blowers. The
results of Phase II testing indicate an
average overall contaminant reduction of
about 50%. A review of the data and the
Phase III operating conditions and
methods shows that the air-lift pump was
not operated under optimum conditions.
Induced Draft Cooling Tower
Studies
The unit used to evaluated this method
was a small demonstration model operated
at air-to-water ratios from 350:1 to 600:1.
Contaminant removals ranged from 48%
to 61%, resulting in a water quality
insufficient to meet state guidelines
levels.
Air Sampling
Because the air discharged from any
aeration treatment system mixes with the
ambient air in the vicininty of the
treatment plant, effects on ambient air
were evaluated during Phases I and III.
Air being discharged from each aeration
unit tested was sampled and analyzed
along with the ambient air. The results
indicated no appreciable impact on the
ambient conditions.
Particulate and Suspended Solids
Measurements
Phase III partially examined how the
introduction of ambient air in aeration
systems affected water quality. Influent
and effluent particulate and suspended
solids analyses were made for the
aeration systems that used ambient air.
Results indicated little or no effect on the
treated water quality. Note, however, that
the ambient air in the Glen Cove area is
relatively clean, and the effect may be
positive in an area with air pollution.
Estimated Costs for Full-Scale
Installations
The estimated costs for full-scale
treatment were based on flow rates of 1,
2, and 5 mgd (3,785, 7,575, and 18,925
mVday). These flow rates were used to
obtain a range of capital and operating
costs (Figures 1 and 2) for full-scale
installations with the following systems:
single-stage diffused aeration, packed-
column diffused aeration, induced-air
packed column spray aeration, packed-
column air-stripping, air-lift pumping,
and resin without pre-aeration. All
estimated costs include expenses for
required buildings for mechanical and
electrical equipment but not those for
laboratories, offices, or worker facilities.
Conclusions
A. Aeration Studies
1. Aeration as a technique for remov-
ing volatile organic compounds
present in ground water will re-
duce cis-1,2-dichloroethylene, tri-
chloroethylene, tetrachloroethylene,
and 1,1,1 -trichloroethane to levels
that will meet existing New York
State guidelines and to levels that
might be universally acceptable.
2. The greatest contaminant removals
were observed with those systems
that used packing material.
3. No apparent effect on the ambient
environment resulted from the air
that was discharged from the
aeration units.
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Figure 1. Capital cost comparisons (Feb.
1983).
4. The packed-column air-stripping
system was estimated to have the
lowest capital and operating costs
of the systems evaluated.
B. Resin Adsorption Studies
1. XE-340® will reduce the volatile
organic compounds present in
Glen Cove well water to < 1 /ug/L.
2. The order of contaminant break-
through was cis-1,2-dichloro-
ethylene, trichloroethylene, and
tetracrtloroethylene.
3. The resin is steam-regenerable,
but proper handling of the result-
ing condensate needs further
study.
4. Countercurrent operation (i.e.,
downward flow application and
upward steam regeneration) was
the optimum mode.
5. Pre-aeration extends resin life
significantly, but the economics
are unattractive relative to resin
adsorption alone.
The full report was submitted in
fulfillment of Cooperative Agreement No.
806355 by Nebolsine Kohlmann Ruggiero
50
40
30
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•Air-Lift Pump System
• Diffused Aeration System
Packed-Column
Diffused Aeration
System
Resin System •
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\j« - Induced-Air. Packed-Column
-Spray Aeration System
Packed- Column
Air-Stripping System •
I
1.0
2.0
3.0 4.0
Flow, mgd
5.0
6.0
7.0
Figure 2.
Comparisons of annual operating costs (Feb. 1983) per 1,000 gal treated (energy
cost at 9C/kW-hr).
Engineers, P.C., for the City of Glen Cove,
NY, under the sponsorship of the U.S.
Environmental Protection Agency.
4
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Dominick D. Ruggiero is with Nebolsine Kohlmann Ruggiero Engineers, New
York, NY 10001; the EPA author. Walter A. Feige (also the EPA Project
Officer, see below) is with Municipal Environmental Research Laboratory,
Cincinnati, OH 45268.
The complete report, entitled "Removal of Organic Contaminants from the
Drinking Water Supply at Glen Cove. NY," (Order No. PB 84-151 349; Cost:
$26.50. 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:
Municipal Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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