United States
Environmental Protection
Agency
Water Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-85/058 Aug. 1985
&EBA Project Summary
Solidification/Stabilization of
Sludge and Ash from
Wastewater Treatment Plants
Philip G. Malone and Larry W. Jones
Tests were performed to determine
the physical properties and chemical
leaching characteristics of the residuals
and the stabilized/solidified products
from two publicly-owned wastewater
treatment works (POTW). The two
POTW waste products included in this
study were an anaerobic digester
sludge from an Imhoff digester and an
ash from a rotating hearth incinerator
used to destroy primary settler and di-
gester sludges.
Three different solidification/stabili-
zation systems were used. One of the
systems was based on the addition of
cement and soluble silicates in various
proportions and formed soil-like solids
that were soft and easily broken. A sec-
ond system used lime and flyash to
form a pozzolanic material that pro-
duced a hard, concrete-like solid. The
third system was based on the forma-
tion of gypsum in the waste after acidi-
fication; these products remained wet
and did not harden. The Imhoff sludge
(anaerobic digester waste) was treated
only with the cement-soluble silicate
process; the incinerator ash was
treated using all three processes.
None of the treated products were
very durable, as none survived the full
sequence of 12 cycles and the wet-dry
or freeze-thaw testing. The concrete-
like, lime and flyash solid had the high-
est durability, surviving 11 freeze-thaw
and 5 wet-dry cycles. The soil-like prod-
ucts survived two or fewer cycles of
both durability tests. The gypsum-
based product remained moist and
putty-like and could not be tested.
The pozzolanic, flyash-lime product
reduced the loss of constituents to the
leaching medium to the greatest ex-
tent, rt also produced by far the small-
est increase in the weight of the waste
to be disposed for any of the pro-
cesses—170% of the dry sludge solids.
These facts coupled with the low cost
of the solidification agents make this
process the most cost-effective of
those tested in this study.
This Profect Summary was devel-
oped by EPA's Water Engineering Re-
search Laboratory, Cincinnati, 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
The effects of contaminating ground-
water and surface water with residues
from publicly owned sewage treatment
works (POTW) are not completely
known. POTW wastes are sludges with
high-organic content that can be dis-
posed of directly or further treated by
incineration, pyrolysis, or composting
to lower the water and organic matter
content before disposal.
The potential for unacceptable levels
of groundwater contamination has
been documented in several cases
where POTW wastes were disposed of
in lagoons, landfills, or land farms. Ele-
vated levels of certain metals (cad-
mium, copper, iron, lead, magnesium,
manganese, silver, and zinc) and the nu-
trients ammonia and nitrate have all
been reported in at least one of several
studies of pollutant losses from POTW
waste disposal sites. In one study, 85
cases of groundwater and/or surface
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water contamination were associated
with leaky sewage sludge impound-
ments in 29 States. Several responses
to this problem are being actively pur-
sued under government and private
auspices. Special land treatment or land
cultivation techniques are also under
active investigation for sewage sludges.
Systems for isolating lagoons and land-
fills with impervious liners and covers
or other containment strategies are also
under development.
This study is concerned with another
alternative—that of chemically stabiliz-
ing, fixing, or structurally isolating the
POTW wastes in a suitable matrix so
that the resulting treated product can be
safely handled, transported, and dis-
posed of using established methods of
landfilling or burial. Chemical fixation
and solidification/stabilization are gen-
eral terms used to designate processes
that can be used to immobilize, isolate,
or otherwise contain wastes. Solidifica-
tion suggests the production of a solid,
monolithic mass with sufficient struc-
tural integrity to be handled, trans-
ported, and disposed of in some con-
veniently sized pieces without requiring
any secondary containers. Stabilization
implies the immobilization of toxic sub-
stances by inducing chemical reactions
to form insoluble compounds, or by en-
trapping the toxic element or com-
pound in a watertight, inert polymer or
stable crystal lattice. In stabilization,
much of the emphasis has been placed
on preventing the waste from coming
into contact with leaching water, or on
creating pH and/or oxidation-reduction
conditions that minimize the solubility
of the toxic constituents. Many fixation
systems combine these two concepts
by producing an impermeable mass
that isolates the waste (or reduces its
leachable surface area) and also main-
tains minimum solubility of the toxic
components.
The three solidification/stabilization
processes included in this study are
those marketed by companies that vol-
unteered to treat the POTW wastes;
they do not necessarily represent a
cross-section of those processes avail-
able commercially or being developed
at this time. One is a pozzolan-based
process using flyash and lime as the
major treatment reagents; another uses
cement and soluble-silicate; and the
third is a process that attempts to pro-
duce solid gypsum in the waste after
acidification.
The POTW residues selected for use
included an anaerobic digester (Imhoff)
2
sludge of relatively high organic con-
tent and an ash from an open-hearth
incinerator.
The leaching procedure used in this
study incorporated several unique as-
pects compared with those found in the
literature. The sample specimens were
of a size and shape (a right cylinder 5 cm
high x 5 cm diam) suggested for use in
the universal leaching procedure (ULP),
which is a proposed standard test for
solidified wastes. The sample speci-
mens had a surface-to-volume ratio of
1.20/cm. The leaching samples were
placed in a cellulose thimble to prevent
particulatesfrom being lost to the leach-
ing medium. The thimble also allowed
the leach testing of untreated and
treated specimens using identical pro-
tocols. The volume of leaching medium
(1 L) was 10 times that of the waste and
was changed daily over the 90-day
leaching test.
Methods and Materials
Description of POTW Wastes
The wastes used in this study repre-
sent typical residuals produced in
POTW operations: ash from sludge in-
cineration and an anaerobic digester
sludge of relatively high organic con-
tent. The two wastes were obtained
from two wastewater treatment
plants—the ash directly from a rotating-
hearth incinerator and the sludge from
the drying bed associated with the oper-
ation of an Imhoff digester tank. Both
treatment plants received waste from
industrial areas that contain heavy
metals, so both residues cause some
disposal problems.
The Imhoff tank sludge is an air-dried,
felt-like material containing recogniz-
able debris such as hair, plastic scraps,
and rubber bands; it has little odor and
has a greenish to grey-black color. This
sludge has been marketed as a soil ad-
ditive. The incinerator ash is a dry, light
powder, brown to orange in color, with
a few large (5- to 10-cm diameter, black,
slag-like agglomerates. The ash was
collected directly beneath the incinera-
tor gratings.
The constituents determined in the
chemical analyses (Table 1) were cho-
sen based on previous studies that indi-
cated they were important indicators of
leaching activity. The Imhoff sludge had
a much higher percent water (42.3%
w/w compared with 22.8% w/w for the
ash and total organic carbon than the
incinerator ash. The sludge also gener-
ally had higher levels of most heavy
metals (especially chromium, selenium,
copper, iron, and zinc) and volatile con-
stituents such as sulfate and cadmium.
Of the toxic metals, only manganese
was present in higher concentrations in
the ash.
Stabilization Techniques
After thorough mixing, each sludge
was sampled using standard proce-
dures, and samples were stored in
sealed plastic containers maintained at
Table 1. Concentration of Selected Constituents in POTW Wastes (mg/kg dry sludge solids)*
Parameter Imhoff Sludge Incinerator Ash
Arsenic
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Selenium
Zinc
Sulfate
Chloride
Total organic carbon
17.4
213
3,060
1,370
22,600
1,130
283
2.65
4,140
1,880
333
127,000
13.4
2.26
566
750
16,800
1,160
783
0.20
705
6,200
455
1,700
*AII values in mg/kg dry sludge solids as digested in hot, concentrated nitric acid.
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room temperature until use. The rela-
tive amounts of dry sludge solids, dry
reagents, and water in the treatment
processes for each sludge processed
are listed in Table 2. Specific informa-
tion on the additives used by each pro-
cessor is not given, as the formulations
are proprietary; only the general cate-
gory of each additive is given when
known.
Process X
Process X processed both sludge
types as shown in Table 2. The waste
and water were slurried in a cement
mixer before the proprietary dry
reagents (cement and other materials)
were added. A liquid reagent was then
added, and the mixture was pumped
into the molds. The molds were covered
with plastic and set aside to cure.
Process Y
Mixes were prepared in a container
equipped with a turbine mixer. After the
ash was adjusted to optimum moisture,
5% additive (on a dry weight basis) was
added. The final mixture was placed in
the molds, compacted with a hand tam-
per, and covered with plastic to cure.
Process Z
The ash, water, and acid reagents
were mixed using a propeller mixer.
More than an hour was required to dis-
sipate the considerable heat produced.
Then a lime and water slurry was added
while mixing continued for another 30
min. The residue was placed in contain-
ers to settle. The treated waste had to be
filtered to remove excess moisture be-
fore it could be compacted in molds.
Leaching Apparatus
The leaching apparatus (Figure 1) al-
lows the manipulation of such parame-
ters as contact time, surface area, and
leachate quantity and renewal fre-
quency. For this study, leaching fluid
was renewed daily, and samples of
leachate for chemical analysis were
taken weekly for the first month, bi-
weekly for the next month, and monthly
thereafter for a total of 90 days of leach-
ing (pH and conductivities were taken
daily). All leaching tests were run and
sampled in triplicate so that a total of
192 leachate samples were generated
for each test. The leaching vessel was
constructed of materials that were inert
with respect to the waste and leaching
fluid. Blanks were carried through each
set of tests.
Table 2. Formulation of Treated and Untreated Waste Samples Used in Physical and
Leach Testing*
Formulation
Sludge and
Process Code
Dry Sludge
Solids
Treatment
Reagents
Water
Core
Weight
(9)
Dry Solids
in Core
(9)
Imhoff Sludge
Untreated
XA
XB
Incinerator Ash
57.5
5.5
75.8
26.0
77.7
42.4
68.5
66.6
121.2
104.8
105.2
69.9
66.4
65.6
Untreated
X
Y
2
77.2
20.6
(59)f
20.0
.
11.3
(3)
15.6
21.8
68.1
(39)
64.4
67.4
106.0
134.3
132.7
52.0
62.2
87.4
67.9
"All data are averages of three cores used in leaching experiment. Variations in weight were less than 5%.
{Formulation for Process Yis not known because of unspecified water additions. Figures given are estimates
derived from chemical analyses and vendor information.
— Leach Liquid
Pumped in Here
,Lid
Column
180 x 115 mm
180 mm
All
Plexiglas
Construction
\-Air Holes
^lllEGIiiii
115 mm •
- Support Ring
_, 60 * 750 mm
Cellulose or
Alundum
Extraction Thimble
-Liquid Level
Test Specimen
50 x 50 mm
Rt. Cylinder
Plastic
Base Support
Drain for Sampling
With Teflon Valve
Figure 1. Design of leaching apparatus.
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The test specimen (a 50- x 50-mm
right cylinder) was supported in the
leaching medium (carbon-dioxide-
saturated, deionized water at pH 4.0 to
4.2) in a 60- x 150-mm cellulose extrac-
tion thimble that was supported both at
the top and the base. The cylinders of
untreated samples were formed in a
small pellet press. All treated samples
were cored from the solid or semisolid
products cured in large molds.
All chemical analyses and sample
preservation were done using EPA-
approved methods. The leaching fluid
was monitored throughout the testing,
and a triplicate set of vessels without
waste samples was run as a control. In
all cases, blank corrections were in-
significantly small.
Physical Testing
Physical testing of the treated sam-
ples was performed to assess their
strength, durability, and trafficability.
Cores of the treated wastes 10 cm in
diameter were submitted for testing for
moisture content, unconfined compres-
sive strength, cone penetration, and
freeze-thaw and wet-dry durability.
Results
Leach Testing
The leaching test was designed to de-
fine quickly and accurately the potential
loss of constituents from treated and
untreated sludges. The waste samples
frequently broke apart or sloughed (ex-
cept those of process Y) in the cellulose
extraction thimbles, increasing their
surface area and accelerating con-
stituent losses. But suspended materi-
als were confined to the extraction thim-
ble and were not collected in the
leachate samples, so not all con-
stituents in the leachates were in solu-
tion. Chemical factors such as solubility,
diffusion rates, and adsorption/desorp-
tion were probably of major importance
to the leaching behavior of the materials
in the vessels because of the small sam-
ple size, its complete submersion, and
the daily replacement of the leaching
fluid.
Three patterns of leaching were ap-
parent for the constituents of the
sludges studied here. For highly soluble
constituents such as chloride and sul-
fate, most leaching took place in the first
few changes of leaching fluid, their con-
centration quickly dropping to a con-
stant, low value. The more insoluble
constituents (lead, manganese, and
chromium, for example) showed rela-
tively constant, low concentrations
throughout the test period. The third
pattern consisted of low initial concen-
trations followed by higher levels later
in the leaching period resulting from pH
changes, common ion effects, or ion ex-
change phenomena. The pH of the
leachate became lower (more acidic) in
all vessels throughout the leaching pe-
riod, especially in the untreated wastes.
The results of the leaching tests are
summarized as the total mass of each
constituent leached averaged for the
triplicate samples. These data are
shown in Tables 3 and 4. Other presen-
tations and derivations of the data are
given in the complete report along with
a thorough statistical analysis.
The three treatment processes pro-
duced very different treated waste prod-
ucts. Only those of process Y were true-
ly solidified into a monolithic block with
good structural integrity. This solidified
product also contained the sludge con-
stituents best of all the treatment pro-
cesses, releasing smaller amounts of
most metals and anions than the un-
treated incinerator ash. Leachates from
process Y-treated ash also had the low-
est conductivities and caused less
change in leaching fluid pH (indicating
little interaction) than those of the other
treated specimens.
Process X produced a cured material
that looked liked a hardened, clay-soil
material that crumbled easily into small
chunks. The samples produced from the
Imhoff sludge by this process were
much softer, perhaps because of the
higher organic content (Table 1). Over-
all, the specimens produced by process
X from both wastes lost smaller
amounts of many constituents to the
leaching medium than the respective
untreated wastes. Leachates from these
samples were more alkaline than those
of any other treated or untreated sam-
ples, indicating the strongly alkaline
character of the treated material. After 2
or 3 weeks of leaching, the conductivi-
ties of the leachate from these samples
were generally higher than those of the
untreated wastes after a comparable
period of leaching, meaning that the
long-term levels of dissolved materials
in their leachate exceeded those of the
untreated sludges. This fact should be
considered in any future evaluation pro-
cedures or leaching test designs.
Process X was the only formulation
used to treat both waste types. Since
treatments XB of the Imhoff sludge
(Table 3) and X of the incinerator ash
(Table 4) were most similar in the
amounts of dry solids and treatment
reagents, they gave the best basis of
comparison of the treatability of the two
Table 3. Total Mass of Constituents Leached from Treated and Untreated Imhoff
Digester Sludges (mg)*
Parameter
Arsenic
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Selenium
Zinc
Sulfate
Chloride
Total organic carbon
Untreated
Imhoff Sludge
0.742
3.30
0.566
3.86
48.4
0.238
11.5
BDLf
120
2680
130
199
Process X,
Treatment A
(XA)
0.049
0.126
1.15
3.20
1.57
0.019
1.48
0.255
3.02
621
28.3
190
Process X,
Treatment B
(XB)
0.020
0.341
3.29
12.38
11.86
0.040
2.48
0.005
12.22
1440
65.0
654
*AII data are the means of three replicates.
tBelow detection limits in all leachate samples.
-------
wastes. The treated products of both
sludges had significantly lower masses
leached than their respective untreated
sludges for arsenic, cadmium, man-
ganese, zinc, sulfate and chloride; but
both leached higher masses of
chromium, copper, and total organic
carbon (TOC) than did their untreated
counterparts. Both of these treated
products had similar physical proper-
ties. Both the Imhoff sludge products
contained high levels of TOC and heavy
metals, and the relative containment
properties of the two treated specimens
were quite similar.
Two different levels of solids and
treatment additives were used by pro-
cess X on the Imhoff sludge (see Table
2). Treatment XA was designed to give
optimum containment, and treatment
XB was typical of commercial treatment
proportions. Although both treated
specimens yielded leachates signifi-
cantly lower than the untreated sludge
leachates in arsenic, cadmium, man-
ganese, zinc, sulfate and chloride, treat-
ment XA lost significantly lower levels
of chromium, copper, manganese, sul-
fate and TOC than treatment XB speci-
mens (see Table 3). The much higher
relative additive level in XA specimens
did increase the containment efficiency
for some constituents and did increase
the strength to a small degree (Table 5).
Selenium, however, appears to be
added in the treatment process, since
none was detected in the untreated
sludge leachate, and since process XA
leached significantly more selenium
than process XB (the reverse of that for
the constituents listed above).
The treated product from process Z
remained wet and did not harden. At the
suggestion of the vendor, the material
was filtered and air-dried before being
tested. Even after this processing, the
material remained wet and would not
hold its shape. Process Z specimens lost
the largest proportion of their con-
stituents in the leaching test and had the
most acidic leachates of all samples
tested. The addition of acidic reagents
to the ash apparently brought many
metals into solution; also, the level of
sulfate in these leachates was ex-
tremely high and persistent.
Physical Testing
A comparison of the physical proper-
ties of the treated sludges permits judg-
ments about the relative ability of the
treatment processes to improve the
handling characteristics of the wastes
and to provide durable materials suit-
Table 4. Total Mass of Constituents Leached from Treated and Untreated Incinerator Ash
(mg)*
Parameter
Arsenic
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Selenium
Zinc
Sulfate
Chloride
Total organic carbon
Untreated
Incinerator Ash
0.472*
0.046
0.336
2.77
BDL
0.325
5.61
BDL
4.48
1050
102
70.6
Process X
BDLf
0.044
0.637
0.389
BDL
0.042
3.56
BDL
BDL
656
55.0
30.8
Process Y
0.511
0.0185
0.0627
0.156
BDL
0.074
0.10
BDL
BDL
111.5
BDL
30.2
Process Z
2.19
0.083
0.038
1.20
8.00
0.625
11.7
BDL
1.38
8970
BDL
42.2
*AII data are means of three replicates.
tBelow detection limits in all leachate samples.
Table 5. Summary of Physical Properties of the Treated Wastes
Imhoff Sludge Incinerator Ash
Physical Property
Free moisture
content (%)
Cone penetrometer
Center (cm)
Edge (cm)
Unconfined compres-
sive strength
Load (N)
N/sq cm
Durability tests
(cycles to failure)
Freeze/thaw
Wet/dry
XA
36.6
0.8
1.4
100.8
24.3
2
2
XB
37.7
0.8
Fractured
114.3
27.6
2
2
X
41.3
0.4
1.4
118.1
25.5
2
2
Y
34.9
ND*
ND
169.9
41.6
11
5
Z
49.8
ND
ND
ND
ND
ND
ND
*Not done on this sample.
able for landfilling. Results of the physi-
cal properties testing are summarized in
Table 5.
All of the treated products made
using process X had physical properties
similar to a crumbly soil-cement with
low strength durability. All contained
between 37% and 42% free moisture
(not bound in hydration reactions).
Process-Y-treated ash was the hardest
and most durable material and had the
lowest free moisture. The treatment
products from process Z did not harden
and were not tested.
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Conclusions
The treatment processes did not al-
ways change the physical properties of
the wastes in a way that would insure
production of a solid. Only one of the
treatment processes produced a mate-
rial that resembled low-strength con-
crete in character—the pozzolanic
flyash-lime process applied to incinera-
tor ash. Other treatment of the incinera-
tor ash produced a soil-like product and
a wet, plaster-like product that did not
harden even after filtering and air-
drying. The two formulations used on
the Imhoff sludge both produced
soil-like products. The durability of the
final products was low; no product sur-
vived the full 12 cycles of the wet-dry or
freeze-thaw testing (Table 5).
The leaching procedure used in this
testing program was designed to con-
trol many of the factors that affect leach-
ing rates, such as surface area, leaching
time, waste-to-leaching-fluid ratio, and
loss of particulates. The concentration
of constituents in the leachates from the
test samples followed one of three dis-
tinct patterns:
1. Highly soluble constituents (e.g.,
sulfate and chloride) were leached
in high concentrations initially, but
very quickly reached low, stable
concentrations near or below the
detection limits.
2. Less soluble constituents (e.g.,
lead and chromium) were found at
relatively constant levels in the
leachates over the leaching period.
In several cases (cadmium, cop-
per, manganese, and zinc) the ini-
tial leachate samples contained el-
evated amounts before the stable
concentration was obtained.
3. Some constituents, like arsenic
and iron, were at or below the de-
tection levels initially but in-
creased in concentration in later
samples, apparently as the pH of
the leaching liquid became more
acidic.
The leaching tests indicated that sev-
eral of the processes significantly
slowed the leaching of selected con-
stituents. Overall, both formulations
used in treating the Imhoff sludge sig-
nificantly slowed the leaching of most
soluble constituents. The formulations
with the higher reagent-to-sludge ratios
were more effective, as predicted. With
incinerator ash, the gypsum-based pro-
cess was not effective in solidifying the
waste or in limiting the loss to the leach-
ing fluid. The lime-flyash process prod-
uct was the most effective treatment for
both solidification and constituent con-
tainment.
The one process used on both types
of waste was the cement/soluble silicate
system. The results obtained by this
process showed no difference in the rel-
ative effectiveness of treating the two
waste types. The appearance, physical
properties, and leachability of the two
wastes fixed by the same process were
quite similar.
Only process Y produced a stabilized
product with more than 20% dry waste
solids (by weight). This process con-
tained about 60% dry waste solids, so
that the weight after treatment was only
about 1.5 times that of the original dry
waste. The other processes increased
the amount of waste to be landfilled by
4 to 10 times the original dry waste
weight. The increase was due largely to
the addition of large proportions of
water (65% to 70% of the final weight of
the treated product). In evaluating the
commercial use of solidification/sta-
bilization, the increased mass for dis-
posal must be considered along with
the improved pollutant containment af-
forded by successful treatment.
Recommendations
Solidification/stabilization as used in
this preliminary study represents a
method of reducing the pollutant poten-
tial of POTW wastes when they are dis-
posed of in landfills. The results appear
to warrant further testing and evalua-
tion. Specifically, actual field tests using
large-scale processing equipment and
treated waste samples may show that
the material behaves differently from
the small samples used in this study.
Large-scale, controlled tests using
treated waste samples that have
surface-to-volume ratios more typical of
those actually encountered in landfill
situations are needed to give more real-
istic estimates of treatment benefits.
The economics of the process and the
increase in waste mass for disposal
should also be carefully addressed. In-
termittent saturation of the treated sam-
ples in contrast to continuous submer-
sion should be considered in future
testing.
This study incorporated treatment
processes with completely different
physical and chemical bases. Tests
need to be made using one overall pro-
cess type to optimize its additive, cur-
ing, and mixing requirements. All of
these studies should be compared with
the results of a standardized solidifica-
tion technique. Comparing selected
physical properties with the leaching
characteristics of each process type
might reveal those properties of the
treated products that can predict their
containment efficiencies.
A standardized leaching test must be
developed to facilitate valid compar-
isons and to increase the predictive
value of bench-scale leaching tests. An
optimum standardized leaching test
would be expected to mimic the condi-
tions under which maximum leaching
takes place, (i.e., be a worst-case test).
Characteristics of such a test would be a
short term of leaching, a small and uni-
form test sample size, an aggressive
leaching fluid, and paniculate contain-
ment for nonsolidified samples. The
leaching apparatus developed for this
study warrants further use in the devel-
opment of a standardized leaching test.
The full report was submitted in fulfill-
ment of Interagency Agreement No.
EPA-IAG-07-0046 by U.S. Army Engi-
neer Waterways Experiment Station
under the sponsorship of the U.S. Envi-
ronmental Protection Agency.
U. S. GOVERNMENT PRINTING OFFICE: 1985/559-111/20628
-------
Philip G. Malone and Larry W. Jones are with the U.S. Army Engineer Waterways
Experiment Station, Vicksburg. MS 39180.
AtalE. Eralp is the EPA Project Officer (see below).
The complete report, entitled "Solidification/Stabilization of Sludge and Ash from
Wastewater Treatment Plants," (Order No. PB 85-207 504/AS; Cost: $ 11.50,
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:
Water Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45^68
BULK RATE
POSTAGE & FEES PAI
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use $300
EPA/600/S2-85/058
11 6 9'! d 4 V = p
ST.
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