United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-84-006 Jan. 1984
&ER& Project Summary
Removal and Treatment of
Contaminated River Bottom Muds:
Field Demonstration
Robert W. Agnew
A field demonstration was conducted
to remove creosote-contaminated
muds from a small stream, the Little
Menomonee River, in Milwaukee,
Wisconsin. River bottom muds from
approximately 1,230 lineal meters
(4,040 lineal feet) of river were
removed and treated during this study
at a cost of about $100.70/lineal meter
($30.80/lineal foot). Analyses before
and after treatment showed that about
76% of the creosote contamination was
removed from this section of the river.
Before the cleanup was started, a
residual level of 5000 mg/kg of creo-
sote was established by bioassay tests
to be safe for incumbent or potential
aquatic species. Skin irritation tests
were also carried out to protect the per-
sonnel involved in the operation.
The field cleanup procedures were
designed to minimize damage to the
shoreline and the river. Two floating
river sweepers equipped with suction
heads were used to dredge mud from
the river bottom and pump it to a land-
based basin, where it was allowed to
settle. The liquid overflow was then
treated with coagulants and clarified,
passed through multi-media pressure
filters, and given a final polishing with
granular activated carbon. The liquid
was then returned to the river, and the
sludges and solids were taken to a
landfill.
This Project Summary was developed
by EPA's Municipal Environmental
Research 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
After a member of a citizens' group
received chemical burns while partici-
pating in a 1971 cleanup of the Little
Menomonee River in Wisconsin, it was
determined that nearly 5 miles of the bot-
tom mud and river banks of this small,
meandering stream in northwestern
Milwaukee County were heavily contami-
nated with creosote or creosote residues.
The creosote had allegedly been dis-
charged to the river over a number of
years as the waste from the preservation
of railroad ties. Observation indicated
that the creosote was not uniformly dis-
tributed along the river but tended to pool
where velocity was low. Testing later
indicated that creosote was unevenly dis-
tributed to depths of 0.6 to 1.0 meter.
First-phase studies were carried out in
1972' under contract to the U.S. Environ-
mental Protection Agency (EPA) to
develop practical means of correcting the
situation. That study found that froth flo-
tation could remove 76.5% of the hexane
extractables, sedimentation could
increase the removal to 98.8%, and
polishing of the liquid phase with carbon
adsorption could result in a total removal
of 99.8%. The results of that study served
as the basis for the field demonstration
reported on here.
'Hansen, C. A andR G.Sanders, Removal of Hazard-
ous Material Spills from Bottoms of Flowing River
Bodies EPA-600/2-81-137 US Environmental
Protection Agency, Cincinnati, OH, 1981. 112 pp
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River Cleanup
Cleanup of any river stretch is a rela-
tively new field, and the Little Menomo-
nee presented numerous challenges. The
river is narrow and shallow, and it
meanders often in the 5-mile stretch that
was the subject of this program. Access
to the river is limited, and its marshy
banks preclude the use of powered vehi-
cles to assist in cleanup of most areas.
Cleanup of the banks consisted of
removing debris, overhanging branches,
creosote-soaked vegetation, creosote-
contaminated bottom and bank muds,
and an accumulation of trash. The latter
had to be moved in flat-bottomed boats to
the nearest access point, where it was
transferred to dumpsters for disposal in a
landfill. Bank areas showing visible signs
of creosote contamination were stripped
and seeded with a quick-germinating
grass seed to minimize erosion. Approxi-
mately 4,000 lineal meters (13,000 lineal
feet) of river bank were cleaned up, and
about 305 m3 of debris were removed.
This effort required some 2,800 man-
hours because of the inability to use
heavy, land-based equipment.
The river bottom was cleaned with the
use of two, shallow-draft, pontoon
supported sweepers equipped with
suction heads that could be maneuvered
on and in the river mud. The suction head
was connected to the land-based
treatment system by flexible rubber
hosing 7.6 cm in diameter. The sweepers
were not powered but were moved
downstream by winch. The second
sweeper had a more sophisticated de-
sign, including hydraulically operated
cutting knives in the suction head to
prevent clogging by debris and to help
remove stable muds. Maneuverability of
the suction boom was also improved to
give a better sweep.
The bottom muds were pumped to a
land-based settling basin where the
heavier solids were removed. The
resulting sludge (6% to 10% solids) was
allowed to thicken and was taken to a
landfill. The liquid supernatant was
transferred by gravity to the mobile physi-
cal chemical treatment system, where
ferric chloride and Altasep 105C* were
added as coagulants. After the solids had
settled, the liquor was pumped through
three multi-media pressure filters
containing anthracite over sand and then
through a single column of granular
activated carbon (Witco Grade 718)
before it was returned to the river.
'Mention of trade names or commercial products
does not constitute endorsement or recommend-
ation for use
The 3.5-month operation cleaned
about 1,231 lineal meters (4,040 lineal
feet) of river bottom, processed 5.8
million liters of river muds, and removed
740,000 liters of grits and liquid sludge.
As cleanup of each river reach was
completed, the section was sampled to
ensure that the residual creosote levels
were lower than the 5,000-ppm limit
established for protection of the aquatic
fauna. If the residual cincentration ex-
ceeded 5,000 ppm, the section was
recleaned.
Though accurate results are difficult to
report, the mean creosote concentration
was 6,911 ppm before cleanup and 1,670
ppm afterward, indicating 76% removal
of the contamination. Within 45 days of
the cleanup, bluegills, largemouth bass,
black bullheads, white suckers,
muskrats, and turtles were sighted in
river areas previously devoid of such
species.
The cost for this operation, excluding
capital equipment, is itemized in Table 1.
Table 1. Clean-up Costs
Item
Bank cleaning
River bottom
Total Cost
$ 24.080
123.975
Cost/lineal
meter
$ 6.04
100.79
Toxicity Studies
To prepare for the cleanup effort, a safe
and acceptable creosote level had to be
established. Bioassays were carried out
using four different species to estimate
aquatic toxicity, and rabbit skin tests were
used to estimate a safe level for human
exposure. In addition, a rapid field test
was developed to monitor the progress of
the cleanup.
The procedure used for bioassay of the
muds was essentially the static
procedure described in the Standard
Methods for the Examination of Water
and Wastewater2 except that air was
added during the tests to ensure high
levels of dissolved oxygen. The test spe-
cies were Daphnia pulex (deGeer) (water
flea), Rhinichthys atratulus (shortnosed
dace), Laponis Macrochirus (bluegill), and
Procambrus sp (crayfish). Though these
species are all native to southwestern
Wisconsin waters, only the dace were
actually present and collected for the
bioassay for the upper, uncontaminated
reaches of the Little Menomonee River.
2M J Taras, A E. Greenberg, R D. Hoak, and M C
Rand, eds Standard Methods for the Examination of
Water and Wastewater, 13th Ed American Public
Health Assoc , New York, New York, 1971 874 pp
The mud used in the controls was taken
upstream of the contamination and
contained only 27 ppm of hexane
solubles; the contaminated mud used in
the tests contained 15,150 ppm.
The bioassays were run in duplicate at
four different levels of creosote loading.
Mud was allowed to settle for 24 hours
before the test species were introduced.
All tests used City of Milwaukee water
treated with activated carbon to remove
chlorine.
The 96-hour survival ratios from the
first series of screening tests
demonstrated that little or no toxicity was
exhibited at creosote levels up to the
15,150 ppm. But signs of distress and
coloration change occurred in all species
at the higher concentrations.
A second series of tests placed added
stress on the test organisms by reducing
the pH or increasing the temperature.
Only the highest creosote concentration
(15,150 ppm) was used. Lethality was
observed only with the dace, but
symptoms of damage (lesions and fungal
infection) were more pronounced in all
surviving organisms. The observed
symptoms appear to be consistent with
the response seen in humans. Though
not toxic at the levels tested, creosote
appears to be an irritant, particularly
when combined with other stresses.
Skin Irritation Studies
Skin irritation tests were carried out on
groups of six albino rabbits with mud
containing various concentrations of
creosote up to 10,000 ppm. Visual
inspection and rating indicated that the
muds were nonirritating at all levels
tested. (All ratings were less than 1.0,
and the Federal Hazardous Substances
Labeling Act Regulations require a score
of 5.0fora chemical to be designated as a
primary skin irritant).
After several crew members suffered
chemical burns, however, tests were
conducted on an oil/water scum or
emulsion found at the site and new muds
containing as much as 20% creosote. In
this series, the 20% creosote samples still
qualified as nonirritants, but the scum
was rated at 4.58, a score that is close to
trie 5.0 of a primary irritant.
Procedure for Field Analysis
A direct comparison procedure was
developed for monitoring the creosote
content of river muds during the cleanup
operation. The procedure consisted
simply of agitating a 5-gram sample of
mud in a mixture of 45 ml water, 0.5 ml
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HCI, and 50 ml petroleum ether for 1 hour
in a closed Erlenmeyer flask. The
supernatant organic layer is then filtered
into screw-capped vials and visually
compared with color standards. The
standards are concentrates of petroleum
ether extracts from the conventional
Soxhlet extraction procedure.
Comparison of field test results and the
Soxhlet procedure demonstrated that any
errors were consistently on the
conservative side (i.e., the field data were
high). The visual test could thus be used
in monitoring the progress of the cleanup.
Conclusions
Bioassays indicate that incumbent and
potential aquatic fauna will be protected
if the residual creosote level in the mud
after cleanup is less than 5,000 ppm of
hexane solubles. As a 24-hour zone of
passage, the creosote level should not
exceed 10,000 ppm. And even though
skin irritation tests demonstrated that the
mud is not a primary skin irritant (even
when it contains 20% creosote), no scum-
generating areas exceeding 10,000 ppm
should be present after cleanup.
The cleanup system developed earlier
and scaled up for this effort achieved the
desired residual levels and restored the
quality of the river so that land and
aquatic species long absent were again
observed.
The cost for cleaning the river banks of
creosote-contaminated trash, debris, and
soil was $6.04/lineal meter. Removal,
treatment, and disposal of contaminated
muds cost approximately $13.35/m2, or
$100.79 lineal meter of river bottom.
Quick response to spills of hazardous
materials is of the utmost importance in
reducing dispersion of the material and
ultimately minimizing the cost of cleanup.
3. The cleanup of the remaining
reaches of the Little Menomonee
should be completed as soon as
funds become available-perhaps by
diverting the river and using land
vehicles.
4. A small dredge such as those used
on the Little Menomonee may be
suitable where the pollutant is not
interspersed with the bottom muds.
Otherwise, damming or diverting
the river coupled with mechanical
removal using front loaders or
bulldozers would be preferred.
The full report was submitted in fulfill-
ment of Contract No. 68-03-0182 by
Envirex, Inc., under the sponsorship of
the U.S. Environmental Protection Agency.
Robert W. Agnew is with Envirex. Inc.. Milwaukee, Wl 53214.
Joseph Lafornara is the EPA Project Officer (see below).
The complete report, entitled "Removal and Treatment of Contaminated River
Bottom Muds: Field Demonstration," {Order No. PB84-129 022; Cost: $ 10.00,
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:
Municipal Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
irUS GOVERNMENT PRINTING OfFICE 1984-759-015/72%
Recommendations
The contractor's experiences during
the cleanup of the Little Menomonee
resulted in the following suggestions:
1. Additional testing should be con-
ducted to determine the levels at
which creosote is dangerous to
humans, particularly in light of the
hypersensitivity exhibited by some
workers.
2. Methods for locating and quanti-
fying contamination of river beds
need to be improved.
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
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