-------
KIC.MIRE 3. CALIBRATION CIIHVB KOR CREOSOTE SATURATED WATEH
C
o
o
1.0
0.0
~ O.I
O
o,
(O
U)
o
o
z
Q
Ul
N
tc
o
z
0.7
o.e
o.s
0.4
0.3
0.2
0.1
0.0
Crown to Rump Length
Mortnlity Index
0!10 1:0 2:8 3:7 4:o 6:5 e-.4 7:3 8:2 0:1
DILUTION (Ratio of Sample Solution to Water)
PIC;UltK 4. MORTALITY RESPONSE AS A FUNCTION Of PRESSURE
10:0
1.0*
8 o.t
CO
0.7
0.6
b o.s
o
>•
g 0.4
S °-3
N
< 0.2
CC
O 0.1
0.0
600.0
750.0
1000.0 1250.0
PRESSURE (psig)
1500.0
1750.0
'•432
-------
DURABILITY OF SLURRY CUT-OFF WALLS AROUND THE
HAZARDOUS WASTE SITES
Raj P. Khera
Department of Civil & Environmental Engineering
New Jersey Institute of Technology
Newark, NO 07102
Yuan H. Wu
Dames & Moore
6 Commerce Drive
Cranford, NJ 07016
M. Khalid Umer
Department of Civil & Environmental Engineering
New Jersey Institute of Technology
Newark, NJ 07102
ABSTRACT
This research was undertaken to study the long term behavior
of a bentonite soil mixture interfacing with various chemical
permeants. A chemically treated "contaminant resistant" Wyoming
bentonite and a non-treated bentonite were tested. The tests show
that the changes in the chemical concentrations have a measurable
effect on the swelling index of the soil but the Atterberg limits
were not affected by similar changes in concentrations. Long du-
ration tests showed the swelling index for "contaminant resis-
tant" bentonite to decrease with time whereas for non-treated or-
dinary bentonite its value stabilized in a much shorter period of
time. For a given soil-chemical combination a straight line cor-
relation was found to exist between swelling index and permeabil-
ity.
INTRODUCTION
In recent years the use of
slurry walls has increased as a
containment structure for haz-
ardous waste sites. However,
there are little data support-
ing the long term effectiveness
of slurry walls in controlling
the migration of pollutants
(2,4,5,9). Johnson, et al. (7)
wrote,"... the technology re-
garding the use of slurry wall
to contain hazardous wastes of
all types is in its infancy ...
further advancement is needed
in developing tests of slurry
wall materials to determine
their long term performance."
Of all the engineering
properties, the permeability of
the backfill is the most impor-
tant parameter affecting the
performance of a slurry wall.
However, the permeability tests
are costly and very time con-
suming. Index properties tests
such as Atterberg limit tests,
though less expensive, are be-
lieved not to be reliable.
433
-------
PURPOSE
The purpose of this inves-
tigation was to study the ef-
fect of chemicals of various
concentrations on the long term
behavior of slurry wall back-
fill materials. The usefulness
of Atterberg limits as an index
for determining the suitability
of a backfill material was
evaluated. Other properties,
such as soil swelling which can
be determined by performing
simple tests, were investigated
for the purpose of developing
correlations between permeabil-
ity and the swelling index de-
fined later in this paper.
APPROACH
Soil Specimen
Two types of bentonites,
an ordinary CS-200, a
"contaminant resistant" SS-100
both supplied by the American
Colloid Co., and a commercially
available clean sand, were used
for preparing backfill mixes.
Specimens for the
swelling test were prepared
by mixing 5ml of dry ben-
tonite powder with various
chemicals. To allow the soil
particles and the liquid to
interact freely, small quan-
tities of soil and chemical
were poured alternately in a
graduate cylinder, to yield
100ml of uniform suspension.
To simulate the long term
conditions, the test specimens
were prepared by directly in-
troducing chemical fluids of
desired concentrations into the
blended soils. The liquid con-
tents for the backfill mixes
were adjusted to approximately
thirty percent to facilitate
the molding of test specimens.
E_qjj i pment
Flexible wall and oedome-
ter cells were used to deter-
mine the hydraulic conductivity
(3). The triaxial cell and con-
trol panel were manufactured by
Trautwein. Oedometers were of
fixed-ring type, and sold by
Soil Test.
In an oedo.meter, vertical
stresses can be applied to sim-
ulate field overburden condi-
tions, and the coefficient of
permeability is obtained by in-
direc.t computations (6). The
oedometer was modified to allow
the direct measurement of per-
meability using the falling
head .technique .
Program
The impermeable nature of
the bentonite is attributed to
its unique swelling properties.
When saturated with water, its
volume expands 10 to 15 fold of
its dry bulk (9). The volume
change is governed by the na-
ture of the fluid.
The swelling tests were
conducted in essentially the
same way as described by Head
(6). The changes in the volume
of soil suspension were
recorded for several months.
To saturate a test speci-
men in the flexible wall perme-
ameter, backpressure was ap-
plied in small increments and
at a slow enough rate to pre-
vent consolidation.
The premixed soil slurry
was placed in the oedometer
ring and was loaded to 25kPa.
Direct measurements of hy-
draulic conductivity were made
prior to each subsequent load
increment .
434
-------
The hydraulic conductiv-
ity for water was determined
when the flow quantity versus
the time curve became linear.
For the chemical permeants the
test was terminated when the
rates of inflow and outflow be-
came equal. Since the speci-
mens were prepared by directly
adding the chemical to the
soil, the entire pore space was
assumed to contain the chemi-
cal. Therefore, the waiting pe-
riod for a two pore volume (2)
displacement was considered
unnecessary.
PROBLEMS ENCOUNTERED
The preparation of back-
fill mix required considerable
time. The usual method to con-
trol its consistency through
viscosity measurements (4,10)
was abandoned in favor of con-
trolling its liquid contents
and slump.
The latex membranes,
which are used to cover the
test specimens in a flexible
wall permeameter are readily
attacked by the chemicals. To
protect a membrane from the
chemical attack the test speci-
men was wrapped two to three
times with a teflon sheet. A
thin coat of silicone grease
was then applied to the teflon.
The latex membrane was then
placed over it.
For maintaining the shape
of the specimen during mount ing
the application of a vacuum was
ineffective due to the relative
impervious nature of the back-
fill mix. A perforated sheet of
aluminum foil wrapped around
the sample outside the latex
membrane provided the necessary
lateral support for the speci-
men .
RESULTS
The Atterberg limit tests
were performed with toluene,
aniline and phenol. The liquid
limit with anil i ne dropped as
the concentration increased.
With phenol the liquid limit
did not change even when the
concentration was as high as
10,000 ppm. No correlation was
observed to exist between the
duration of soaking and the
liquid limit. The data with
toluene also showed a consider-
able spread. Thus, for the
chemicals of the given concen-
trations, the liquid limit did
not prove to be a useful index.
Further Atterberg limit tests
were curtailed in favor of
swelling tests.
S_vjg.llin,g__Tesits_
To correlate free swell
with different chemicals a
swelling index Si is defined
as fol 1 ows :
Si= Swc/Sww
where S is soil free swelling
with a chemical and S with
demineralized water.
Initially the value of S.
for CS-200 was forty-five per-
cent larger than that for SS-
100. However, gradually the SS-
100 specimens expanded and af-
ter twenty-five days S. became
constant and its final value
was only fifteen percent less
than that of CS-200.
Among the organic liquids
aniline showed (Fig. 1} the
most effect on S.. With the
concentration of 1,000 ppm and
10,000 ppm, the initial val-
435
-------
ties of S. were almost equal,
but the 1,000 ppm suspension
slowly increased its volume and
became constant in about sixty
days. For 10,000 .ppm ,anil ine,
S. continued to drop. This
change became significant after
four months and by the eighth
month the difference between
the two S. values had
increased from thirty percent
to forty percent. Toluene and
phenol also demonstrated some
effect on S-, though not as
much as aniline. Similarly,
Acar, et al. (1) reported
greater reduction in free swell
for concentrated aniline than
for phenol .
Fig. 2 and Fig. 3 show
the swelling indices for SS-100
with the highest chemical con-
centrations. The observation
periods were almost twelve
months for most of the chemi-
cals. Note that the inorganic
hydrochloric acid has the
greatest effect on S.. Also,
potassium chromate has the low-
est concentration but shows
considerably more effect on Si „
than other liquids with rela-
tively higher concentrations.
The higher charge on chromium
ion is believed to have caused
greater reduction in the thick-
ness of the double layer and,
therefore, lowered its
swelling index. S, for. hy-
drochloric acid and chromium
did not stabilized but for all
other chemicals it became sta-
ble after two months.
Hydrochloric acid affected
the swelling index of CS-200
(Fig. 4) to a greater extent
than that of SS-100. However,
for CS-200 the swelling index
did not decrease with time as
was the case with SS-100. Ini-
tially the S. value for CS-200,
was thirty percent lower than
that for SS-100 but Si de-
creased with time and in four
months the difference between
the S. values for the two soils
had reduced to less than five
percent. The extrapolation of
S. for SS-100 shows it to be
lower than that for CS-200.
With the other chemicals, the
S. values for CS-200 were, ei-
ther equal to or greater than
those for SS-100. Since SS-100
is chemically treated and is
"contaminant resistant" one
would expect its properties to
be less affected by the chemi-
cals. However, the observed re-
sults contradict the expected
behavior. ,
The swelling index is more
sensitive to the chemical type
and its concentration and ap-
pears to be better suited for
predicting the effect of chemi-
cals on soils than the Atter-
berg limits. A swelling test is
easier to perform and requires
less skill than the Atterberg
limit test, even though it
takes longer to complete. Al-
though the behavior of a soil
suspension is not the same as
its in-situ response, S- can
provide a qualitative measure
of the influence of a permeant
on the soil structure.
jj/drau 1 i c Conduct, jyjjy.
As shown in Fig. 5, with
all other conditions remaining
the same (void ratio, consoli-
dation pressure, etc.), the
swelling indices appear to show
a linear relationship with the
hydraulic conductivity for most
of the chemical tested. The
hydraulic conductivity
increases as the swelling index
decreases. These results are in
agreement with the Gouy-Chapman
theory which depicts the
contraction of the diffused
436
-------
double layer primarily as the
reason for the higher
magnitude of permeability in a
clay mass.
When using concentrated
chemicals the change in
permeability is usually
dramatic and easily detected.
At lower chemical concen-
trations the changes in the
permeability are small and not
detectable. The swelling index,
on the other hand, is shown to
be much more sensitive to small
changes in the chemical concen-
trations. It is, therefore, a
good indicator'of. a soils sen-
sitivity to chemicals and the
resulting changes in their
properties.
The permeability values
from pedometer and falling head
measurements showed a good
agreement and are presented
elsewhere (8).
CONCLUSIONS
The use of the swelling
index is a reasonable way for a
qualitative evaluation of a
soil-chemical interaction. The
swelling index is much more
sensitive to both the chemical
type and its concentration.
Long duration tests showed
that the swelling index for
"contaminant resistant" ben-
tonite continued to decreased
over a long period of time.
However, for non-treated ordi-
nary bentonite the swelling in-
dex stabilized in a much
shorter period of time.
For a given soil-chemical
combination a straight line
correlation was found to exist
between swelling index and
permeability. As the swelling
index of a soil decreases its
permeability increases. This
relationship can be used to
predict the trends in soil
permeability even at lower
chemical concentrations.
ACKNOWLEDGEMENTS
This research Was funded
by the National Science Founda-
tion Industry/University Center
for Research in Hazardous and
Toxic Substances, and the De-
partment of Civil and Environ-
mental Engineering, at the New
Jersey Institute ;o.f. Technology,
Newark, NJ. Their support is
great fully acknowledged.
REFERENCES
1. Acar, Y. B., Hamidon, A.,
Field, S. D., and Scott,
L.,"The Effect of,Organic
Fluids on Hydraulic Conduc-
tivity of Compacted Kaolin-
ite," Hydraulic Barriers in
Soil and Rock, ASTM, John-
son, A. I., Forbel, R. K.,:
Cavalli, N. J., and Petters-
son, C. B., Editors, 1985,
pp. 171-177.
2. Anderson, D.,Crawley, W. ,
and Zabcik, J. D.," Effect
of Various Liquids on Clay
Soil: Bentonite Slurry Mix-
tures,"Hydraul ic Barriers in
. Soil and Rock, ASTM, John-
son, A. I., Forbel, R. K. ,
Cavalli, N. J., and Petters-
son, C. B., Editors, 1985,
pp. 93-102.
3. Daniel, D. E., Anderson, D.
C., and Boynton, S. S.,
"Fixed-Wall Versus Flexible-
Wall Permeameters," Hy-
draulic Barriers in Soil
and Rock, ASTM, Johnson, A.
I., Forbel, R. K. , Cavalli ,
.N. J., and Pettersson, C.
B., Editors, 1985,, pp.
107-126.
437;
-------
4. D'Appolonia, D.J.,'"Soil
Bentonite Slurry Trench Cut-
off s,"Journal of Geotechni-
cal Engineering Division,
ASCE, Vol.106, NO.GT4,
April, 1980, pp. 399-419.
5. Evans, J. C., Fang, H. Y.,
and Witmer, K. ."Influenc of
Inorganic Permeants upon the
Permeability of Bentonite,"
Hydraulic Barriers in Soil
and Rock, ASTM, Johnson, A.
I., Forbel, R. K., Cavalli,
N. J., and Pettersson, C.
B., Editors, 1985, pp. 64-
73.
6. Head, K. H., Manual of Soil
Laboratory Testing, Vol. I
and Vol. II, John Wiley &
Sons, New York, 1981.
7. Johnson, A., Forbel, R. K.,
Cavalli, N. J., and Petters-
son, C. B., "Overview," Hy-
draulic Barriers in Soil and
Rock, ASTM, Johnson, A. I.,
Forbel , R. K., Cavalli, N.
J., and Pettersson, C. B.,
Editors, 1985, pp. 1-6.
8. Khera, R. P., Wu, Y. H.,
and Umer, M. K.,"Durability
of Slurry Cut-Off Walls
around the Hazardous Waste
Sites," Progress Report, NSF
Industry/University Copera-
tive Research Center, NJIT,
Newark, NJ, 1986.
9. US EPA, "Slurry Trench Con-
struction for Pollution
Migration Control,"EPA-
540/2-84-001, U. S. Environ-
mental Protection Agency,
Cincinnatti, OH, 1984.
10. Xanthakos, Petros P.,
Slurry Wall , McGraw-Hill
Book Company, New York,
1979.
1.2 r
WoUr
_ Set Typ«: BwitonlU SS-100
0.0
Fig. 1
Elapsed Time (Days)
Swelling Index of'chemically-Treated Bentonite, SS-100 with Aniline.
438
-------
. Soil Type: B«ntonite SS-100
0.7'
0.6
• Wotar
• * Anllln* 1000ppm
o Ph«nol 1000ppm
« 1.1,1-Triehloroathona 1000ppm
D Tolu«n« 1000ppm
0-5 Q ' ' 90 ' ' 180 ' ' 270 ' ' 360 ' ' 450
Elapsed Time (Days)
Fig. 2 Comparisons of Swelling Index for Chemically-Treated Bentonite, SS-100,
with Organic Chemicals.
1.2 r
1.0
0.8 -
x
o
•o
0)0.6
9
9
0.2
0.0
Soil Typ»: Bsntonlta SS-100
* Water
- • Potassium Chromate SOppm
• NaOH 0.1 N
A Hcl 0.1 N
i , i i i i i i i i i t i
90 180 270 360 450
Elapsed Time (Days)
1— — — — — ^ » f
Fig. 3 Comparisons of Swelling Index for Chemically-Treated Bentonite, SS-100,
with Inorganic Chemicals.
439
-------
1.2
1.0
xO.8
0)
•o
jr
a>0.6
0.2
0.0
Potassium Chromate SOppm
Phenol lOOOppm
e*
7 Toluene lOOOppm
1-rtr-
Hcl 0.1N
9
Soil Type: Bentonite CS-200
Water
NaOH 0.1N
400
100 200 300
Elapsed Time (Days)
Fig. 4 Comparisons of Swelling Index for Ordinary Bentonite, CS-200.
1.2 r
1.1
x
o>
•o 1.0
D>
150.9
to
0.8
0.7
10
* Aniline 10OOppm
n Toluene 10OOppm
A Phenol 10OOppm
I I t I I
10
Permeability (cm/sec)
10-r
Fig. 5 Relationships between Swelling Index and Permeability for Backfill Mix
with 10% Chemically-Treated Bentonite, SS-100.
Disclaimer
The work described in this paper was not funded by the U. S. Environmental
Protection Agency. The contents do not necessarily reflect the views of
the Agency and no official endorsement should be inferred.
440
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ASSESSMENT OF LEACHATE MONITORING AND TOXICITY IN
GROUNDWATER AROUND IOWA MUNICIPAL LANDFILLS
Burton C. Kross, Ph.D., P.E.
Department of Civil and Environmental Engineering and
Department of Preventive Medicine and Environmental Health
University of Iowa
Iowa City, IA 52242
ABSTRACT
Historical monitoring data .collected since 1977 at Iowa municipal
landfills were analyzed .to determine if groundwater was contaminated,by
landfill leachates. Monitoring data for indicator parameters - pH, chloride,
and specific conductance - were examined statistically at 67 permitted
municipal/county landfills using the student t-test and an analysis of
covariance technique. Landfills were ranked into quartiles from greatest to
least probability of contamination, based on historical data. A stratified
random sample of 19 sites was then selected for further assessment using the
Microtox toxicity screening procedure, chemical screening tests (TOG and TOX),
and selected chemical analyses (ammonia, sulfate, nitrate, and heavy metals).
Results of toxicity and chemical screening procedures for groundwater
from 93 wells at 19 landfills suggest a poor correlation between the two
screening approaches. Wells that screened positive (12 total) for the TOX
test were generally not the same wells that were considered toxic (10 total)
according to the Microtox procedure. A significant correlation exits between
Microtox and TOG data, as expressed by a Spearman rank correlation coefficient
of 0.29 and a p-value of 0.006. Results of this study also suggest that TOG,
ammonia, and sulfate are not good indicator parameters for monitoring leachate
migration from landfills in Iowa.
The best approach to improving the quality of monitoring data around Iowa
landfills is to increase the number and improve the location of new monitoring
wells at each site. Commitment of financial resources in the future should be
directed toward improved hydrogeologic representation of groundwater flow near
landfills, not better chemical characterizations of groundwater quality.
INTRODUCTION
An important issue facing the
nation is the protection of groundwa-
ter resources. An integral part of
any protection strategy will be to
define the extent, significance, arid
solutions to groundwater cqntamina-
441
-------
tion from existing, identified, and
unknown landfill sites. Initial
investigations (1) of this issue by
the Iowa Environmental Protection
Division (formerly the Dept. of
Water, Air, and Waste Management)
focus on the 125 permitted landfills
in the state, which utilize about
10,000 acres.
Review of existing records indi-
cates that about 50% of these
landfills are known to generate
leachates. However, existing
groundwater monitoring programs
required at these landfills have
detected leachate contamination of
groundwater at less than 10% of the
sites. This information may suggest
one or more of the following sce-
narios .
a) that groundwater contamination
from landfill leachates is not a
problem,
b) that contamination is not yet a
problem,
c) that contamination is not detected
because of the insufficient number or
location of monitoring wells,
d) that contamination is not detected
because the most commonly required
indicator parameters may not reliably
indicate the presence of leachate
contamination, or
e) the methods used to analyze
existing monitoring data are not
effective in determining contamina-
tion.
PURPOSE
Research was conducted to
address scenarios c), d) and e)
through investigating the relation-
ship between toxicity of landfill
leachates and other measured ground-
water quality parameters. The
objectives of this study were as
follows:
1. Evaluate, analyze, and summarize
existing monitoring data from all
permitted municipal/county landfills
in Iowa,
2. Conduct toxicity screening tests
and limited chemical analyses on
leachates and groundwater samples
from chemical analyses on leachates
and groundwater samples from 20 sites
selected by stratified random
sampling procedures,
3. Attempt to correlate results of
the toxicity screening tests and
chemical analyses with existing
indicator screening tests and
chemical analyses with existing
indicator parameter data, and
4. Determine the applicability of a
short-term bioassay screening
procedure, the Microtox test (2), and
several chemical indicator parameters
for detecting leachate contamination
of groundwater from landfills.
APPROACH
In an attempt to improve the
homogeneity of field data, only
municipal/county sanitary landfills
(86 total) were considered for the
database. Based on review of
existing monitoring records, 19
landfills were deleted from further
evaluation for various reasons, i.e.
limited historical data from new
monitoring well installations, only
surface water monitoring at the site,
or farm wells not properly con-
structed or located for monitoring
purposes. The remaining landfills
were then classified into two groups.
Sites that included monitoring wells
located up-gradient and down-gradient
from the landfill were designated as
Type I landfills (52 total). Type II
sites (15 total) had monitoring wells
in only down-gradient locations.
442
-------
Historical monitoring data were
available on a semiannual basis
beginning in 1977-81 for most wells.
Chemical indicator parameters,
chloride, pH, specific conductance,
and chemical oxygen demand (COD data
for 1/4 of sites), were entered into
the SAS, Version 5 (3) statistical
assessment program for further
analyses. The database includes 318
monitoring wells with about 10,000
observations.
Each monitoring well was
classified as up-gradient or down-
gradient. These designations were
based on review of engineering and
soils reports; potentiometric surface
calculations performed using recorded
water-level elevations, topographic
elevations, and stratigraphic
sequences for each monitoring well;
and limited personal communications
with agency staff.
The first level of statistical
analyses used the standard T-test and
a more sophisticated analysis of
covariance (4) procedure for existing
groundwater monitoring data for at
all Type I landfills. The sites were
then ranked and grouped into quar-
tiles according to the calculated
probabilities that a significant
difference existed between up-
gradient and down-gradient concentra-
tions for the historical indicator
parameters of chloride and specific
conductance.
A stratified random sample was
constructed by randomly selecting 6
sites from the first quartile
(greatest probability of contamina-
tion), 5 sites from the second
quartile, 3 sites from the third
quartile, 3 sites from the fourth
quartile, and 3 Type II sites. This
technique permits calculation of an
inclusion probability for use in
weighted regression analysis. Hence,
the method preserves the statistical
validity of this study for drawing
inferences about potential groundwa-
ter contamination from landfills
throughout Iowa.
At each of the 20 selected
landfills, samples of groundwater
from existing monitoring wells were
collected using standardized field
procedures. Measurement of pH,
specific conductance, chloride,
ammonia nitrogen, nitrate, and
sulfate was performed using a
portable spectrophotometer (Hach
Model DR/3). Samples were analyzed
for total organic carbon (TOG) and
total organic halides (TOX) by the
University Hygienics Laboratpry. At
three sites, analyses for 11 heavy
metals and 28 volatile organics were
performed on 24 environmental
samples, including landfill leach-
ates.
The Microtox single point
screening methodology for 100%
samples was used for the groundwater
samples. Responses for three
replicate samples from each well were
compared to the response of three
diluent blanks. Sample pH was
adjusted to 6.0 to 7.0. Testing
temperature was 10°C. This procedure
produced a response that was ex-
pressed as a positive or negative
percentage of light reduction. A
positive light reduction suggests a
toxic response while a negative light
reduction indicates stimulation or
possibly hormesis (5).
The Microtox test is based on
detecting changes in natural light
production from a specific strain of
a marine luminescent bacterium,
Photobacterium phosphoreum, when
exposed to a toxic challenge. The
bacteria are carefully cultured and
harvested to insure genetic stability
and are provided by the manufacturer
in lyophilized form. Each test
involves about 3 million of the
reconstituted bacteria (30 ul. per
443-
-------
1.0 ml. sample). The Microtox Model
2055* Toxicity Analyzer System used
for this procedure contains a
spectrophotometer that measures the
differences in light output of
samples compared to light output of
diluent blanks. Light measurements
were recorded 5 and 15 minutes
following inoculation of the sample
with bacteria.
Results of toxicity testing and
chemical analyses for 93 wells at 19
landfills (one landfill declined
participation) were analyzed using
SAS correlation and regression
procedures.
PROBLEMS ENCOUNTERED
Despite careful use of existing
records and historical hydrogeologi-
cal observations, field investiga-
tions at the 19 landfills detected
probable discrepancies in previous
designations of monitoring, wells as
up-gradient or down-gradient. Nine
wells were reclassified based on
field verification and a third
classification "within the fill" was
created for six wells that were
actually monitoring groundwater in or
near old landfill waste cells. It is
important to recognize that field
verification of monitoring data is
essential. Changes for 15 of 93
wells resulted in reordering and
significantly different statistical
inferences at 8 of the 19 landfills.
Field observations were also
important relative to assessing the
effectiveness of ' each existing
monitoring network. At 8 of the 19
sites, additional wells would be
required to establish a minimal basis
for monitoring groundwater movement
around the site. The most common
deficiency was the lack of good up-
gradient locations to serve as a
baseline. Another monitoring problem
occurs when landfilled areas become
local recharge zones, thereby
changing the local groundwater flow
direction as the landfilling pro-
gresses.
The standard Microtox test
procedure necessarily involves
dilution of the sample to about 70%
of its original concentration;
followed by serial dilutions at even
lower concentrations to obtain data
for a log-log plot of concentration
vs. normalized light production. For
many of the groundwater samples this
standard Microtox procedure at 15°C
resulted in "negative" data points or
stimulation of the bacteria at the
lower concentrations. Perhaps
nutrients in the sample produced true
stimulation of the bacteria or
perhaps hormesis from low levels of
toxicants was the cause of these
observations. In any event, it was
not possible to calculate the normal
Microtox toxicity endpoint, i.e., the
EC20 or EC50, for most of the
samples. Better results for toxicity
screening purposes were obtained
using the Microtox single point
screening methodology for 100%
samples.
RESULTS
The preliminary statistical
analyses of 52 Type I landfills
determined that 13 sites historically
had significantly higher (p-value
<0.05) concentrations for chloride in
down-gradient wells vs. up-gradient
wells. Similarly, 16 landfills had
the same condition for historical
specific conductance measurements. A
total of 7 landfills had significant
differences in historical records for
both indicator parameters. From a
research viewpoint this ranking of
sites was useful to assure that field
testing encompassed the full range of
expected groundwater contamination
around landfills during the limited
444
-------
field study. The environmental
policy and regulatory significance of
these rankings are of obvious
importance, as well.
Validation tests on metal
solutions and diluted landfill
leachates were performed to determine
the sensitivity of the Microtox
single point screening method.
Reference standards containing known
concentrations of metals regulated by
the Safe Drinking Water Act were
analyzed. Based on the results given
in Table 1, the Microtox method
appears to be sensitive enough to
detect small amounts of leachate in
groundwater. Additional chemical
analyses for leachates from two sites
are given in Table 2.
Summary data for the Microtox
tests and other chemical parameters
measured at 93 wells monitoring 19
Table 1. Calibration Data
Compound
Arsenic
Silver
Lead
Selenium
Cadmium
Mercury
Chromium
Barium
Chlorine,,
w/ Ammonia
Chlorine,
w/ Ammonia
Millipore Water
Water Leachates
Leachate A ,
Leachate B
Leachate C
Leachate D
Cone.
me/L
0.05
0.5
0.05
0.5
0.05
0.5
0.01
0.1
0.01
0.1
0.002
0.02
0.05
0.5
1.0
10
0.1
5.0
1.0
5.0
400:1
20:1
400:1
20:1
400:1
20:1
400:1
20:1
Microtox
NPLD-5 min NPLD-15 min
14.1
21.5
25.6
24.1
16.1
22.5
14.1
11.7
5.2
1.1
15.1
4.3
4.3
4.3
0.7
0.0
40.5
327.
3.1
2.4
89.6
11.2
161.
-1.3
23.8
8.7
404.
17.5 .
36.2
28.0
65.2
19.4
41.6
14.4
16.0
,8.1
5.0
17.9
9.4
6.6
6.8
4.2
6.3
172. ,-
—
11.8
3.6
84.0
28.0
194.
-0.5
21.0
14.0
770.
Notes: NPLD = net % light decrease, 10°C.
Lowest cone, of metals is drinking water standard
445
-------
Table 2. Analyses of Landfill Leachates
Parameter
Site A
Site B
Parameter
Site A
Test
NPLD5
NPLD15
TOG
TOX
NH3, N
N03, N
S04
PH
Sp. Cond.
Cloride
Del. Cloride
Del. Sp. Cond.
Mean
5.1
-5.6
14.1
58.4
0.5
1.2
97
7.1
1110
23.3
15.6
130
S.D.
13.5
42.5
31.2
94.0
0.6
2.6
150
0.3
760
65
84
470
Ran?
Low
-15
-27
.5
5
0
0
0
6.0
300
1
-76
-480
je
High
77
386
200
540
3.5
16
785
8.2
5200
460
593
1750
Note: Microtox tests 10°C. All concentrations in mg/L,
except TOX in PPB. Del. = delta, down-gradient minus up-
gradient
Site B
Tox (PPB)
TOG (PPM)
Ba (PPM)
Cr (PPM)
As (PPM)
Cd (PPM)
Pb (PPM)
320
610
.16
< .02
0.03
0.02
0.13
910
2500
1.2
0.36
< .01 (PPM)
0.02
0.19(PPM)
Mg (PPM)
Se (PPM)
Zn (PPM)
Cu (PPM)
Ag (PPM)
Trichloro-
floromethane
(PPB)
260
0.01
0.78
0.06
< .01
1414
300
< .01
0.58
< .05
< .01
< 5
Table 3. Summary Results of Toxicity and Chemical Testing
Table 4. Microtox Data
Classification System
NPLD-5
> 32
18 - 32
10 - 18
0-10
< 0
Class if icat ion
very toxic
toxic
slightly toxic
indeterminate
non-toxic
# of
wells
5
7
8
40
33
Table 5. TOX Screening
Classification System
TOX
>178
100-178
56-100
32- 56
< 32
Classification
strong positive
positive
weak positive
indeterminate
negative
# of
wells
6
6
7
23
49
446
-------
landfills are presented in Table 3.
Results from any toxicity screening
procedure should not be considered
absolute measurements of toxicity. A
classification scheme for grouping
Microtox results into a ranking
system is suggested in Table 4.
Similarly, chemical screening tests
like TOX could be grouped into
classifications that indicate the
need for additional specific chemical
analyses. See Table 5. These
rankings are based on increments of
0.25 on a log 10 scale. For example,
wells that were classified as very
toxic/toxic by the Microtox test or
strong positive/positive by the TOX
test could be analyzed for heavy
metals, specific volatile organics,
or other suspected contaminants.
Microtox and chemical analyses
data are very skewed data sets with
several observations beyond three
standard deviations from the mean.
These observations were deleted for
statistical analyses using non-
parametric methods. The correlation
between Microtox and TOX data is not
significant, resulting in a Spearman
rank correlation coefficient of 0.15
with a p-value of 0.15. Stated
another way, the wells that screened
strong positive/positive for the TOX
test usually were not the same wells
that were very toxic/toxic based on
the Microtox procedure. This result
is not surprising since Microtox
procedures can detect a much broader
range of toxicants in groundwater
than TOX measurements. , Moreover,
Microtox is not particularly sensi-
tive to low concentrations of
halogenated organics.
A significant correlation exists
between Microtox and TOG data, with a
Spearman rank correlation coefficient
of 0.29 and a p-value of 0.006. This
correlation between total organic
carbon and Microtox toxicity is
consistent with the broad screening
nature of both procedures.
An analysis of the 13 study
sites, which have up- and down-
gradient wells (76 total), using the
inclusion probability method yields
statistical inferences about likely
monitoring results for all landfill
monitoring wells in Iowa. The data
presented in Table 6 represents the
best estimate, based on this strati-
fied random sample of 13 sites, of
expected values for chemical parame-
ters and toxicity in groundwater
near Iowa landfills.
Highly significant differences
(p-values <0.01) exist between up-
gradient and down-gradient observa-
tions for the Microtox procedure,
TOX, specific conductance, and
chloride. Of particular note,
measurements of TOG were essentially
the same for up and down locations
while up-gradient measurements of
sulfate, and ammonia were actually
higher than down-gradient observa-
tions. These data suggest that TOG,
sulfate, and ammonia testing are of
limited utility for monitoring
potential landfill contamination.
RECOMMENDATIONS
1. The computerized database for
existing landfill monitoring networks
should be maintained and updated with
semi-annual data by the Iowa Environ-
mental Protection Division. Designa-
tions of wells as either up- or down-
gradient should be carefully reviewed
for all sites by regionally based
state inspectors who regularly visit
each landfill.
2. The best approach to improving
the quality of monitoring data is to
increase the number and improve the
location of new monitoring wells at
each landfill.
3. Given the inherent limitations of
the existing monitoring database, the
simple student t-test procedure is
447
-------
Table 6. Best Estimate for Statewide Monitoring Results
Up-gradient (n=19)
Down-gradient
(n=57)
Range
Parameter
Microtox
NPLD5
TOX
TOG
Sp . Cond .
Chloride
Sulfate
Nitrate, N
Ammonia, N
mean
2.0
40
7.8
870
5.2
92
1.8
0.6
low
-7.8
5.0
.5
415
1.0
10
0
0
high
23.4
160
68
1880
99
700
8.3
3.1
mean
3.8
62
8.5
1080
20.5
88
0.9
0.4
low
-14.9
5.0
1.0
300
1.0
0
0
0
high
45.8
540
150
3550
460
785
12
1.5
Student
t-test
p-value
.0085
.0001
.6060
.0003
.0001
-.0281
-.0060
-.0301
appropriate for determining the
significance of differences between
up-gradient and down-gradient wells.
Student t-tests should be performed
in conjunction with each monitoring
period. Examining data from
individual wells alone with actions
taken if single observations deviate
from the mean by more than 3 standard
deviations will not effectively
utilize the monitoring database.
4. Two baseline monitoring wells
carefully located in up-gradient
locations that will not be disturbed
by on-going landfilling operations
should be required at each landfill.
If the landfill could affect the
groundwater table and additional
aquifers, two baseline monitoring
wells should be placed in each
groundwater regime. These wells
may necessarily be located off
landfill property to insure constant
baseline data.
5. At the time of permit renewal,
each landfill operation should submit
results of . a detailed hydrogeology
report based on site-specific field
testing to justify the number and
location of on-going groundwater
monitoring wells.
6. A recording rain gauge, field
measurements of infiltration rates
into the landfill cap, and field
estimates of evapotransporation rates
over the landfill area should be
added as permit requirements to
assist with water balance calcula-
tions needed to predict leachate
generation rates.
7. Each landfill should establish a
surface water monitoring program to
include upstream and downstream
samples of intermittent drainage
ditches, ponding water, or streams
draining the site. If local
groundwater flows are known to
contribute to streamflow in the
immediate vicinity of the landfill,
sampling of the stream should also
monitor this condition.
8. Sampling of , farm wells in the
vicinity of landfills may have public
relations benefits (assuming all
results are negative), but these
samples have little monitoring
benefit because of inconsistent well
construction and significant poten-
tial for other interference con-
tamination, i.e. feedlot or agricul-
tural chemical spills. Farm wells
should be deleted from future
monitoring requirements.
9. On-site wells used for potable
water supply by landfill workers
should be added to the monitoring
448
-------
requirements. Testing requirements
should parallel those required for
small public water systems under the
Safe Drinking Water Act.
10. Although current indicator
parameters (chloride, pH, and
specific conductance) are probably
not the best approach to consistently
detect groundwater contamination from
landfills, extreme caution should be
exercised before adding new chemical
parameters to monitoring require-
ments. Any additions should have a
specific rationale and stated
interpretation guidelines. As
previously noted in no. 2 above,
financial resources should be
directed toward improved hydrogeolo-
gic representation, not chemical
characterizations.
11. Further assessment of screening
procedures like TOX and Microtox may
ultimately lead to inclusion of one
or more of these tests to a complete
groundwater monitoring program.
ACKNOWLEDGEMENTS
The financial and technical
support of the , U.S. Environmental
Protection Agency and the Iowa
Division of Environmental Protection
is greatly appreciated. Analytical
support and equipment for toxicity
measurements were provided by the
University Hygienic Laboratory and
Microbics Corporation. Special
thanks go to Barbara Torney, a
geologist, who assisted with inter-
pretation of hydrogeological data.
Protection Strategy, Environmen-
tal Commission, Des Moines, IA,
106 p.
SAS Institute Inc., 1985, SAS
User's Guide: Basics, Version 5
Edition, Gary, NC, 1290 p.
Silver, C.A., 1985, Statistical
Approaches to Groundwater
Monitoring, Environmental
Institute of Waste Management
Studies, University, Alabama, 18
p.
Stebbin, A.R.D., 1982, Hormesis
- the stimulation of growth by
low levels of inhibitors, In:
The science of the Total
Environment, Elsevier Scientific
Publishing Co., Amsterdam,
Netherlands, pp 213-234.
DISCLAIMER
The work described in this paper
was not funded in total by .the U.S.
Environmental Protection Agency. 'The
contents do not necessarily reflect
the views of the Agency and no
official endorsement should be
inferred.
REFERENCES
1. Beckman Instruments Inc., 1982,
Microtox System Operating
Manual, Carlsbad, CA, 94 p.
2. Hoyer, B.E., J.E. Combs, R.D.
Kelley, C.C. Leatherman and J.H.
Seyb, 1987, Iowa Groundwater
449
-------
-------
LEACHATE SYNTHESIS FOR CLAY
AND
FML COMPATIBILITY TESTING
Stephen S. Odojewski
Waste Resource Associates, Inc.
2576 Seneca Avenue
Niagara Falls, NY 14305
ABSTRACT
In complying with permitting requirements for land disposal facili-
ties, a new facility faces certain problems not encountered by an
existing facility. In particular, the required demonstration of the
compatibility of the liner system with the wastes and associated consti-
tuents to be handled becomes much more complicated. A logical approach
can however be employed to formulate a synthesized leachate which can
then be used to produce the data needed to satisfy the requirements of
this demonstration.
In this particular project, the leachate which was synthesized was
shown to be compatible with both a FML of high density polyethylene
(HOPE) and a clayey soil liner.
INTRODUCTION
As part of the permitting
process for any existing or new
land disposal facilities in the
United States, the permit applicant
must demonstrate that the various
materials chosen for the liner
system are compatible with the
hazardous wastes and associated
.constituents to be disposed. In
the case of an existing facility,
the compatibility demonstration
usually involves obtaining a
representative sample of leachate
generated from on-going land
disposal operations and subjecting
the various components of the liner
system to the appropriate compati-
bility testing protocols. Since a
new facility cannot begin to accept
any hazardous wastes for disposal
until a permit is issued, the
compatibility demonstration becomes
a somewhat more complicated under-
taking. The new facility permit
applicant is forced to somehow
synthesize a leachate which is
representative of the types of
wastes intended to be disposed
at the facility. This leachate
must then be used to perform
the required compatibility tes-
ting.
451
-------
PURPOSE
Whatever approach is used to
formulate the synthesized leachate
must be technically defensible with
respect to ensuring the leachate is
representative of future land
disposal activity. As certain
assumptions are made in developing
the approach, the permit applicant
must be sure to employ a "worse
case" scenario. This is particu-
larly important when selecting the
range of waste constituents to be
included in the synthesized leach-
ate as well as the concentrations
in which they must be added. Only
with a synthesized leachate repre-
sentative of future land disposal
operations (or a more highly
contaminated leachate) can the
compatibility of the materials of
construction selected for the
proposed liner system be verified.
APPROACH
The first step in formulating
a synthesized leachate involved
determining which waste types the
proposed facility intends to
handle. Part 261 of Title 40 in
the U.S. Code of Federal Regula-
tions presents the methodology by
which a waste generator determines
if his waste is "hazardous." There
are two basic mechanisms by which a
waste can qualify as "hazard-
ous"; inclusion in any one of four
"lists" presented in Subpart D of
Part 261 or meeting any one of four
"characteristics" presented in
Subpart C of Part 261. In re-
viewing each of the waste types
described in Part 261, the permit
applicant must decide whether any
exclusionary land disposal restric-
tions such as physical form (i.e.
liquid or presence of free liquid)
or unique hazards (i.e. highly
reactive, extremely low flash
point) will prevent the proposed
facility from accepting that
waste. It should be noted that
many of the EPA wastes listed in
Subpart D, might initially be
thought to be excluded from consi-
deration because they are liquids
may, in fact, be accepted by the
facility because of the mixture
rule of 40 CFR 261.3 or because
they are residues derived from the
treatment of a particular Subpart D
listed waste. Examples are spill
residues (soil) contaminated with a
liquid commercial chemical product
or the solidified form of a semi-
solid waste.
For each of the Subpart D
wastes which the facility intends
on handling, Appendix VII to Part
261 lists the major hazardous
constituents the EPA expects to be
present in that waste. The con-
stituents listed in Appendix VII
that are contained in the various
listed wastes to be handled by the
facility formed the initial basis
for determining which chemical com-
pounds were to be contained in the
synthesized leachate. This initial
list was further expanded after a
review of the hazardous constitu-
ents presented in Appendix VIII to
Part 261. Append be VIII constitu-
ents which have a flash point less
than 140 F or which may be
present as minor waste constituents
were then added to the initial list
of chemical compounds to ensure it
was as complete as possible.
The permit applicant then
estimated the annual volume for
each of the various waste types
that the facility intends on
accepting. These estimates were
452
-------
based on the type and number of
generating industries located
within the intended service area of
the facility. Ihe annual volume
estimates were then sub-divided and
placed into either "low", "medium"
or "high" receipt volume cate-
gories.
A concentration was then
assigned to each constituent which
was to be included in the synthe-
sized leachate as a result of the
review of Appendix VII and Appendix
VIII. This concentration was
established based on the number of
wastes which contained that chemi-
cal compound and the relative
volume of these wastes with respect
to the annual volume of all wastes
which are expected to be received.
Once the completed list of
constituents and their correspon-
ding concentrations had been
compiled, the appropriate material
for the FML was chosen. Existing
manufacturer compatibility data for
each of the pure chemical compounds
contained in the synthesized
leachate was examined and the FML
which offered the widest range of
chemical resistance was chosen.
In a new facility which
intends on accepting a relatively
wide variety of different waste
types, it is not uncommon to
develop a lengthy listing of
constituents which must be combined
in order to properly synthesize the
leachate to be used for testing.
Such was the result of this effort.
The listing may contain many
chemical compounds which are either
insoluble in water or have limited
solubilities (i.e. chlorinated
hydrocarbons). In order to
attempt to dissolve as many of the
water-insoluble substances in the
synthesized leachate, it was
helpful to prioritize or rank the
chemical compounds with regard to
their water miscibility or solubi-
lity. Four categories for the
prior it izat ion or ranking were
established. These categories
included compounds which are
either;
• completely miscible with water
in all proportions,
• water soluble but not com-
pletely miscible in all
proportions,
• limited water solubility
• insoluble (negligible solubi-
1ity in water).
The chemical compounds which
fall into the first category were
initially added to the distilled
water used as the base for synthe-
sizing the leachate. These were
followed by those in the second
category and so on. By using this
sequence of addition, it is more
likely that some of the compounds
with either limited or negligible
solubilities in water (but which
may be soluble in certain organics)
were actually "pulled into" solu-
tion and dissolved into the synthe-
sized leachate.
PROBLEMS ENCOUNTERED
As the laboratory responsible
for actually formulating (mixing)
the synthesized leachate began
contacting various chemical supply
vendors, certain chemical compounds
could not be obtained. Some exam-
ples of Appendix VIII hazardous
constituents which were found to be
commercially unavailable are:
• Dichlorophenylarsine
• Diethylarsine
453
-------
• alpha, alpha-Dimethyl-
benzylhydroperox ide
• Lead phosphate
• Nickel carbonyl
• symme tr ical-Tr in itrobenzene
Certain chemical compounds
which were deleted from the list
because they were too volatile to
be expected in any appreciable
concentration level in the uncon-
tainerized wastes handled by the
facility and too volatile to be
effectively dissolved into the
synthesized leachate. Examples of
these highly volatile compounds
are:
• Carbon disulfide
• 1,1-Dichloroethane
• Ethylene oxide
• VinyL chloride
Other chemical compounds were
found to be unstable when intro-
duced into an aqueous matrix and
therefore deleted from the synthe-
sized leachate. Examples of these
compounds are:
• Antimony compounds
• Methyl isobutyl ketone
peroxide
• Phosphorous sulfide
• Toluene diisocyanate
In order to enhance the
solubility of certain inorganic
metallic chemical species in the
leachate, the chloride salt of
various inorganic metallics was
chosen in lieu of other chemi-
cal forms with lesser water solu-
bilities.
RESULTS
Upon completing the addition
of all chemical compounds which
could be obtained commercially,
15.0 liters of leachate was pro-
duced. The synthesized leachate
separated into three distinct
phases (or layers). These phases,
from top to bottom, were:
- 8.0 liters of a clear, yellow-
green liquid;
-4.5 liters of a flocculant
precipitate;
- 2.5 liters of a heavy sludge.
Since the minimum technology
guidelines issued by EPA for double
liner systems for landfill facili-
ties requires that an upper FML be
overlain with a primary leachate
collection zone designed to prevent
clogging, only the clear, yellow-
green liquid was used in the
ensuing compatibility testing. A
well-designed primary leachate
collection zone will prevent any
of the fiocculant precipitate
and/or heavy sludge from pene-
trat ing down into the zone and
blinding its hydraulic transmis-
sion capabilities. Therefore, the
only phase from the synthe-
sized leachate likely to penetrate
the entire thickness of the
primary leachate collection zone
and contact the primary FML would
be the clear, yellow-green liquid.
In order to confirm precisely
which of the chemical compounds
originally added to the synthesized
leachate blend did in fact remain
in the upper liquid phase, the
clear, yellow-green liquid was
analyzed. Nearly all of the
inorganic (metallic) chemical
compounds added to the leachate
remained in varying degrees in the
upper aqueous layer while approxi-
mately only 20% of the organics
added were detected. The table
which follows lists the various
inorganics and organics, the
concentrations in which they were
added to the leachate and the
454
-------
concentration for that constituent
found in the upper aqueous layer.
Synthesized Leachate Analysis
pH = 2.7
specific gravity =1.12
conductivity = 185,000
TOC = 5,000 mg/1
organics: (mg/1)
phenol 130
2-picoline 130
2-chlorophenol 56
1,2-dichloroethane 55
methylene chloride 43
nitrobenzene , 32
cyclohexanone 25
aniline 21
nitrophenol 20
chloroform 18
1,1,2-trichloroethane 17
p-chloro,m-cresol 14
MIBK 12
n it rop ropane 12
propanenitrile 12
2-methyl phenol 12
pyridine 10
dichlorophenol 9.1
dinitrotoluene 8.5
methyl chloroform 8.0
tr ichlorophenol 7.1
acetone 7.0
acrylonitrile 6.5
ethyl acrylate 6.2
dinitrobenzene 5.7
1,1-dichloroethane 5.6
benzyl alcohol 4.3
butanbl 2.5
benzene 2.3
3-chloro,2-butanone 1.8
trichloropropane 1.5
chlorobenzene 0.5
inorganics (anions) : (mg/1)
chloride 43,000
sulfate 34,000
nitrate 10,000
inorganics (cations): (mg/1)
sodium 34,000
potassium 12,400
aluminum 4,100
magnes ium 3,680
copper 2,130
zinc 1,310
boron 1,200
cadmium 1,020
1 ith ium 640
bismuth <500
lead 392
manganese 367
nickel 268
selenium 202
strontium 180
mercury 110
arsen ic 106
antimony 53.3
cobalt 43.3
calcium 34.8
molybdenum 28.5
phosphorus 22.0
tin 15.4
iron 9•3
thallium 6.1
beryllium 1.6
vanad ium 1.3
silver 0.22
barium 0.13
There were many organics which
were added to the synthesized
leachate that were not identified
in the analysis of the upper
aqueous layer. It is felt that
these organics were either reacted
in some way to form the insoluble
precipitate or sludge or volati-
lized.
The clear, yellow-green liquid
was used to subject a high density
polyethylene FML to compatibility
testing using EPA Method 9090 and a
sample of clayey soil material to
compatibility testing using EPA
Method 9100.
455
-------
HOPE Testing
The three figures which follow
detail the testing data for percent
weight change, yield strength and
percent elongation at break
for the high density polyethylene
FML subjected to Method 9090
compatibility testing.
« WEIGHT CHANCE
2.O • •
23° C
YIELD STRENGTH (PSI)
S.BOO - -
3.0OO
2.SOO - -
23°C
30 60
' DAYS
No significant deterioration
of the high density polyethylene
FML was identified in the Method
9090 testing which was conducted.
% ELONGATION AT CREAK
tooo- -
so eo
DAYS
120
456
-------
Clay Testing
The recompacted permeability
of a clayey soil sample was deter-
mined by ASTM Method 2434 using
both deionized water and the
synthesized leachate as a permeant.
The results of that testing is as
follows:
Permeant % Moisture k (cm/sec)
Deionized 13.9 3.99 x 10~8
Water
Synthes ized
Leachate:
Trial No.
Trial No.
Average
13.6
14.2
13.9
2.60 x 10'
,-8
2.45 x 10
-8
2.53 x 10'
,-8
The synthesized leachate had
no discernable effect in deteriora-
ting or altering the permeability
of the clayey soil.
ACKNOWLEDGEMENTS
This project was conducted on
behalf of our client, Sechan
Limestone Industries, Inc. (Por-
tersville, PA), who graciously
agreed to share this information.
The blending of the synthe-
sized leachate, analysis for
inorganic constituents and the
clayey soil testing was conducted
by the Calspan Advanced Technology
Center (Buffalo, NY).
The analysis for organic
constituents was conducted jointly
by Advanced Environmental Systems,
Inc. (Niagara Falls, NY) and Compu
Chem Laboratories (Research Trian-
gle Park, NC).
The testing of the HDPE liner
was conducted by Gundle Lining
Systems, Inc. (Houston, TX) .
DISCLAIMER
The work described in this paper
was not funded by the U.S. Environmental
Protection Agency. The contents do not
necessarily reflect the views of the
Agency and no official endorsement should
be inferred.
457
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-------
MINIMIZATION OF WASTE UTILIZING HIGH PRESSURE MEMBRANE FILTER PRESSES
C. Robert Steward, P.E.
Shriver Filter Presses/Eimco Process Equipment Company
1476 Montgomery Highway
Birmingham, AL 35216
ABSTRACT
Presentation to discuss the technology used in high pressure filtration
utilizing variable volume membrane filter plates to produce the highest
dry solids and minimal volume of liquid waste when dewatering a hazardous
waste slurry. Presentation will address,effects of pressure, conditioning,
operation of membrane (diaphragm) plates, and areas to consider in the
design of an installation. ' " *
Disclaimer
The work described in this paper was not funded by the U.S. Environmental
Protection Agency. The contents do not necessarily reflect the views of
the Agency and no official endorsement should be inferred.
*******
WHERE ENTIRE PAPER HAS NOT BEEN INCLUDED IN THESE PROCEEDINGS COPIES WILL BE
AVAILABLE IN THE CONFERENCE LOBBY.
459
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-------
SOIL STANDARDS FOR HAZARDOUS WASTE DISPOSAL
AND CLEANUP IN THE NETHERLANDS
F. B. DeWalle
TNO, Delft, 2600 AD, Holland
University of Washington, Seattle, WA 98195, U.S.A.
ABSTRACT
The present study established reference values for uncontaminated soils in
relation to clay content and organic matter. These reference values are to be
used to designate soils that are contaminated by hazardous waste and releases
from point sources. The limited dose-effect relationships for the different
soil functions indicate levels comparable to the reference values. Soil remed-
iation techniques were generally not able to reach these reference values and
disposal of cleaned-up soil therefore still requires usage restrictions.
INTRODUCTION
The Netherlands is a densly populated
country with 15 million inhabitants
occupying 41,160 km.2. Many conflicting
demands are placed on soil use. More than 2
billion m3 groundwater are annually
withdrawn (influencing 14% of the land area)
and 125 million m^ sand and clay are used
for building materials each year. A large part
of the annual 5 million tons domestic refuse
and 20 million tons industrial waste is
disposed of on the soil. In addition, 12 tons
cadmium, 400 tons lead and 1600 tons zinc
are added to the soil through wet deposition
from the air. More than 7500 contaminated
locations, covering an estimated 20% of the
total soil area have been identified of which
more than 1600 need remedial action
(VROM,1987; Nypels, 1986).
The urban areas, covering 7.6% of the
land, contribute to soil pollution through
leaking sewers , corroded tanks and
infiltrating urban runoff. The soil usage for
roads (1.8% of the land) contribute as a result
of contaminated runoff, spills and deposition
from the air. The agricultural areas (64.5%
of land use) receive large quantities of
fertilizer, sewage sludge and pesticides.
Even the unused natural areas and and
forests (covering 12.1% of the land) and
water (covering 9.0% of the land) are subject
to degradation through upwelling
contaminated groundwater, deposition from
the air and polluted sediments (Biemond,
1978).
SOIL PROTECTION POLICY
Soil protection has received
considerable attention in the Netherlands.
The Interim Soil Cleanup Act covering the
period 1982-1988 deals primarily with
remedial action of locally contaminated areas
and dump sites that pose a harmful effect to
human health or the environment.
The Soil Protection Bill which was first
submitted to parlement in 1980 became law
on January 1, 1987. It is the intention of the
Act that soil use does not diminish its
multifunctionality, i.e., its agricultural
function (crop production and grazing),
groundwater recovery function, ecological
function, mining function and carrier
function, primarily through prevention
measures. The Act provides for a general
level of protection through soil quality
standards and goals and source reduction. It
allows for additional protection in watersheds
461
-------
or groundwater protection areas and soil
protection areas (unique natural habitats, rare
soil strata or archeological sites). The soil
quality standards can deal with physical
(mechanical degradation), biological and
chemical aspects of the soil and are to be
specified in subsequent rules and regulations
(article 20). A policy distinction is made
between chemicals that are harmfull and
cause irreversible damage that must be
prevented from coming into contact with the
soil whenever possible (black list) and those
that may be deposited on the soil providing
strict requirements are met (grey list). Point
sources are covered by ICM (isolate, control,
monitor) criteria, while input from the diffuse
sources (deposition from air, heavy metals in
fertilizer, sewage sludges, etc.) should equal
output (leaching, crop removal).
The first soil criteria established in 1983
under the Soil Clean-up Act were based on a)
nature and concentration of the pollutant; b)
local situation through site specific risk
analysis in which an individual risk of 10"
6/year per substance is maximum tolerable
and 10" 8 is negligible; and c) use and
function of the soil and restoration of its
multifunctionality. It contains "A" or
reference values below which a "good" soil
quality exists, "B" values below which a
preliminary investigation is likely because of
uncertainly regarding good soil quality and
"C" values below which possible harmfull
effects for human health or the environment
can occur requiring further investigation and
above which the soil is heavily polluted
requiring remedial investigations and cleanup
preferrably back to the "A" value. These
indicative A,B,C- concentration values for
both soil and groundwater are shown in
Figure 1. The values for group 1 and 2
components present average background
concentrations while the values for group 3
through 7 represent analytical detection
limits. The EC directive for drinking water
standards apply for deep groundwater and for
drinking water (EC, 1980). The major
shortcoming of the values were the limited
lexicological basis and past experience on
which they were based, the inability to
differentiate according to soil type and the
absence of criteria for radioactive substances
io,ooq
1000
A"B" FUKIH.
D"A" REFERENCE
ZnCrNiSn Mo Cd Zn Cr Ni Sn M3 Cd
BaPbCuCoAsHg BaPbCuOoAsHg
EtEMEOTS
Figure 1. Indicative values for remedial
action ("C"), further investig-
ation ("B") and reference value
("A").
and bacterial contaminants (Moen et al.,
1968). In April, 1986, the Ministry of
Housing, Physical Planning and
Environment (VROM, 1986) proposed
"tentative reference values" for a good soil
quality that met the multifunctionality
criterium. The proposal was submitted to the
Technical Soil Commission (TCB) appointed
by the Minister, to advise on the technical and
scientific merits of the proposal. The material
presented below was the basis for the TCB
advice. It was developed by six task forces
with a total of 43 academic participants
(TCB, 1986).
ESTABLISHMENT OF REFERENCE
VALUES FOR A MULTIFUNCTIONAL
SOIL
The reference values are based on an
evaluation by the TCB of 118 soil samples
collected from the top 10 cm in natural areas
(Edelman, 1984) after removal of the mulch
layer. On these areas no obvious harmfull
effects resulting from the chemicals were
462
-------
observed and the soil was presumed to have
retained its multifunctionality. A linear
regression was established between the
concentration of the element and clay content
(percentage smaller than 2 micron meter and
organic matter content as shown in Table 1.
Some outliers were eliminated because of
special circumstances (natural arsenic
deposits, elevated copper and zinc at
archeological sites, etc). The strongest
correlations between the concentration of the
element and the clay content were noted for
Cr, Ni for all samples. The correlations for
Cu, Zn, Pb and As improved considerably
when only the "mineral samples" with an
organic matter content below 250 g/kg were
considered. The correlation between the
organic matter content and the difference
between concentration estimated from the
clay content and the measured value (DE)
was strongest for Cd, Zn and Pb. A
comparison of the regression coefficient
show that an increase in the organic matter
content has a three times larger effect than an
increase in clay content in predicting the
increse in cadmium concentration (3.3:1).
For Pb the ratio is 1.2:1 while for Zn and Hg
it is 0.45:1 and 0.41:1, respectively. No
relationship with organic matter content was
found for As and Cu (although mineral
samples had higher mean concentrations) and
Ni and Cr (Figure 2.)
The background values from natural
areas can be compared to data collected for
uncontaminated pleistocure sands
(Breeuwsma, 1986) and marine and river
deposits (Salomons, 1983) as shown in
Table 2. The values for the natural areas,
extrapolated to zero clay content, (intercept
value a) are generally higher than the
pleistocene sands probably as a result of areal
deposition. The regression coefficients with
respect to clay content however, show a
much closer agreement The data also show
the large difference between metal content in
the mulch layer and the different horizons
indicating the importance of specifying
sampling depth.
The natural area data were used to
establish an upper limit equal to two times the
standard deviation in the relation between
element concentration and clay content
TABLE 1. Relationship between dement concentration and clay content or organic matter
content for all samples, for "mineral" soil samples (H < 250 g/kg) and for
"organic" soil samples (H) 250 g/kg).
element samples relation*
Cr
Ni
Cu
Zn
Cd
Hg
Pb
As
*The linear regression is (1): E = a+bL, with E = element concentration (mg/kg), a =
intercept, b - regression coefficient, L = clay or lutura content (g/kg) or (2): DE =
difference between concentration estimated from clay content and measured concentration,
a = intercept, b = regression coefficient, H = organic matter or humic content (g/kg). The
number of observations (n), the correlation coefficient (r) and the residual standard
deviation (sx,y) are also shown.
an
mineral
organic
all
minezal
organic
all
mineral
organic
all
rmncrsl
organic
all
mineral
organic
all
mineral
organic
all
mineral
organic
all
mineral
organic
1
1
2
1
1
2
1
1
2
1
1
2
1
2
2
1
1
2
1
1
2
1
1
2
22,5
21,2
0,707
-0,416
3,55
1.41
9,34
27,9
15,5
-39,4
0,333
0,157
-0,197
0,0676
0,0511
0,0503
27,0
15,*
-3.8
4,25
3,03
7,59
0,190
0,205
0,0833
0,0911
0,0608
0,0582
0,27.10-3
0,236
0,278
0,125
0,578 . 10-3
0,623 . 10-3
1,68 . 10-3
0,205 . 10-3
0,181 . 10-3
0,079 . 10-3
0,0872
0,0845
0,095
0,0432
0,0371
0,33 . 10-3
116
89
117
89
113
85
30
93
69
26
111
83
30
99
79
22
103
81
24
110
83
29
0,922
0,917
0,934
0,954
0,732
0,962
0,004
0,771
0,929
0,608
0,191
0,435
0,645
0,456
0,503
0,269
0,422
0,775
0,609
0,796
0,919
0.012
12,2
124 -
4,87
4,04
8,81
2,37^
14,9
31,0
17,0
40,3
0,464
0,186
0,502
0,062
0,045
0,069
28,98
10,0
30,4
5,15
2,31
0,83
AGRICOI/TOSAL AREAS (B)
0 250 500
CLAY COOTEOT (G/KG)
Figure 2. Relation between chromium concen-
tration and clay content in soils
463
-------
allowing an exceedance of 2.5%. These
relations were compared with analysis results
of 266-966 mineral soil samples (H below
250 g/kg) collected from the top 20 cm in
agricultural soil (Van Driel and Smilde, 1982;
Wiersma et al., 1985). The exceedance for
Cr (Figure 2) and Ni was only 0% and 1%,
respectively, (n=266), while for Cd it was
6% (n=965). For Pb, Zn and Hg it was
11%, 12%, and 13%, respectively. For As
and Cu it was as much as 21% and 40%,
respectively, reflecting use of copper
containing chemical and fecal fertilizers and
pesticides.
ESTABLISHMENT OF REGULATORY
SOIL LIMITS
In order to establish regulatory limits
suitable for practical use simplification of the
different relations in Table 1 is necessary. It
is desirable to formulate one relationship that
can be used for all elements. The general
relationship is: a simplification of the
different relations in Table 1 is necessary. It
is desirable to formulate one relationship that
can be used for all elements. The general
relationship is:
Gij = ai + bi. Lj + ci. Hj (1)
Gy = concentration of elements in soil j.
(mg/kg)
ai, bi, ci = contents of element i
Lj = percentage clay in soil j.
Hj ~ percentage organic matter in soil j.
This can be simplified to:
Gij = C0i (a + bLj + c Hj) (2)
CQ: = reference value of element for standard
soil
a,b,c = constants similar for all elements
The equation proposed by VROM (1986)
selected the constants as follows:
Gij = C0i(0.5Lj+1.5Hj)(3)
The value of the organic matter in (3) is
weighted 3 times more than the clay content
From Table 1 it can be seen that this only is
the case for Cd and that for other elements the
organic matter influence is much lower. A
disadvantage of (3) is that it underestimates
TABLE 2. Background Concentration's in Pleistocene Sands and Marine Deposits
Samples
Cr Mi Cu Zn
Content mg/kg
Uncontaminated pleistocene 8,9 5,5 2,0 7,4 0,08 2 9
sands (83, C, G horizon)
Natural Areas**
21,2 0,7 3,6 15,5 0,33
15,8
Marine deposits from Dollard 72 29 13 68 0,25 21
estuary collected in 1922*
Marine deposits from Dollard 69 28 11 70 024 25 • '•'•'
endiked before 1880,
collected from top 20 cm*
River deposits from Rhine 87 35 24 87 0,29 29
polders endiked before
1780, collected from top
20cm*
Concentration in different
horizons in sandy soil:
Ao: Mulch layer 13 8,5 27 ,122 1,3 161
Al: Humic top layer 13 2,2 3,2 14 0,31 23
B2: Precipitation layer 9,5 2,1 1,4 7,0 0,12 4,8
B3: Identical 9,0 3,1 1,4 7,0 0,08 2,7
C: Original material 8,8 4,2 1,8 7,1 0,07 3,1
Regression Coefficient h with rexpr.r.t try c]?y
Marine deposits 1,189 0,071 0,033 0,182 0,51.10'3 0,054
River deposits 0,234 0,089 0,066 0,239 0,63.10'3 0,078
Natural areas** 0,205 0,091 0.058 0,278 0,62.10j3 0.085
* The values for marine and river deposits are standardized for a fine fraction (smaller than
16 urn) of 50%.
**See Table 1 calculated from intercept
the metal content in sandy soil with a low
clay content (resulting in high exceedance of
the regulatory limit) and overestimates the
value in organic soils (resulting in a filling up
of the norm.)
The TCB therefore proposed as an
improved equation:
Gij = C0i (10 + 0.5 Lj + 0.25 Hj) (4)
In this equation the organic matter contributes
only half as much as the clay content to the
estimated element concentration, while the
intercept constant a results in values closer to
the analytical results in sandy soil. The
reference values for "standard" soil (H:10%;
L:25%) are given in Figure 3. The Gij values
464
-------
for other soils are derived from the value of
the standard soil by multiplying the reference
value C0i by (0.5 Lj + 1.5 Hj)/27 according
to (3) and by (10 + 6.5 Lj+ 0.25H)/25 in (4).
The results for sandy soil, clay soil and
organic soil are shown in Figure 3. The
agreement between measured value and
predicted value using (4) is quite good and is
therefore suitable for regulating purposes in
evaluating contaminated soils and directing
cleanup operations.
ESTABLISHMENT OF REGULATORY
GROUNDWATER LIMITS
Regulatory limits or reference values
that are not to be exceeded were also
proposed for groundwater. The values were
based on the analytical results of the country
wide shallow groundwater monitoring
network (Van Duyvenbooden et al., 1984)
and on theoretical equilibrium calculations
(VanHeck and Wassenberg, 1984) as shown
in Table 3. The largest overestimation was
noted for Hg. The observed values were also
compared with the average rainfall
concentrations (using both dry and wet
deposition data) and
concentrations using a
concentration increase as
evapotranspiration (Rivm,
measured values are generally below the
calculated infiltration concentrations
indicating substantial adsorptive processes in
the soil especially for Cu, Zn and Pb. For As
the reverse was observed, likely resulting.
from As upwelling from deeper marine
deposits. The proposed VROM and TCB
regulatory limits allow for a 5-10%
exceedance. As soluble concentrations vary
greatly because of variations in pH, ORP,
and complexities, a differentiation according
to clay content and organic matter was not
feasible.
EFFECT -BASED REFERENCE VALUES
The above proposed approach to
establish reference values for a
multifunctional soil uses the upper limit of the
currently observed ranges in relation to
specific soil parameters in soils that are not
polluted ("preserving current quality")- An
10,000
infiltration
three fold
a result of
1984). The
0 T I I I I I I
'Zn Pb Cu Cd Zn Pb Cu Cd Zn Pb Cu Of'Zn Pb Cu Cd
Cr Ni As Hg Cr Ni As Hg Cr Ni As Hg Cr Ni'As Hg
ELEMENTS
Figure 3. Element concentrations predicted by
the VRQM and TCB model and maximum
observed concentrations for
different soils.
TABLE 3. Concentration in groundwater and proposed reference values (ug/1).
Ele-
ment
Cr
Ni
Cu
Zn
Cd
Hg
Pb
As
Mean
Concen.
of Ground-
water
Monitoring
Network
0,7
3,2
5
30
0,4
0,02
4,8
3,0
Concen
Exceeded
by 10% of
Samples
1,0
16
14
150
2,4
0,03
7
5,4
Theoretical Mean
Equilibrium Concen.
Concen.
4
3
4
26
0,7
0,3
25
7
in Rain-
water
0,5
1,5
7,5
53
0,4
0,02
13
0,8
Mean Proposed
Concen. Refer.
Proposed
Refer.
ofinfil- Values by Values
tration
water
after
Evapotra-
nspiration
1,5
4,5
22,5
160
1,2
0,06
39
24
VROM
5
10
10
70
1
0,2
15
10
by TCB
„
1
15 _
15
150
2
0,05
15
10
465
-------
alternative approach evaluates each of the
multiple soil functions with respect to dose-
effect relationship and level of irreversible
damage. The most sensitive function is then
used as limit to protect the overall
multifunctionality of the soil. This approach
was not chosen at this time, but may be used
when sufficient data for each of the soil
functions become available. For some
elements, however, this approach can already
be taken.
The ecological function was defined
through the functioning of the detrital food
chain, often representing more than 90% of
the production in an ecosystem. The
saprophage invertebrates were evaluated with
respect to nutrient cycles and food chain
accumulation of the biologically available
portion.
No effect levels for Cu were observed
below 60 mg/kg for Lumbricis rubellus and
below 30 mg/kg for Allolobophora longa
whereby cpconproduction was a more
sensitive indicator than mulch decomposition.
A pH increase greatly increased no-effect
levels. The no-effect-level for Cd was 20
mg/kg for L. rubullus. The isopod Percellio
scaber showed no effect levels for juvenile
production at 2000 mg/kg Zn and 10 mg/kg
Cd, and for mulch consumption at 1500
mg/kg Zn and 2 mg/kg Cd. The collembol
Orchesella cincta showed no effect levels of
64 mg/kg for Cd. All of the above
concentrations reflect values in the upper
mulch layer which are higher than the average
concentrations in the top 10 cm of the profile
(Table 2).
All investigated oligochaets, isopods
and collembols accumulated several metals
especially Cd and to a lesser extent Zn
possibly leading to further food chain
accumulation.
The public health effects of
contaminated soil were considered through
summation of six exposure routes through
which the soil contaminants could reach
humans. The approach followed that used by
Van Wynens (1982) and Verwy and Luiten
(1984). The multimedia model assumes a
proportionality between mass flux (human
intake) and soil concentration as shown in
Table 4. It was also assumed that the total
intake originating from contaminated soil
corresponded to 50% of the ADI with the
TABLE 4. Calculation of Cd Soil Concentration Limit Corresponding with Cd Intake of
50% of ADI through Six Exposure Routes
Exposure
Route
Relation
Paramaters
Selected
Values
Soil/Dust xi=ai.fj.y xi=rate through soil ingestion (mg/person.day) , -
Ingestion f i=uptake + correction child/adult (kg/person.day) 5 x 0,2
ai=transfer coefficient (-) 0,0002
y=soil concentration (mg/kg)
Drinking X2=a2-f2-y X2=rate through drinkng water ingestion (mg/ . .
Water person.day.
a2=soil desorpa'on coefficient (-) 0,002
f2=drinking water factor (kg/person.day) 2
y=soil concentration(mg/kg)
Vegetable X3=a3.f3.y x3=rate through vegetable ingestion (mg/person.
day)
a3«=transfer coefficient soil/crop (-) 0,02-0,1
f3=vegetable consumption (kg/person.day)
Meat/Milk/ X4=a4.f4.y x4=rate through meat ingestion (mg/person.day)
Eggs a4=transfer coefficient soil/crop/animal (-) 0,147
f4=consumption (kg/person.day) 0,279
Fish x5=as.fs.y xs=rate through fish ingestion (mg/person.day) 0,012
a5=transfer coefficient soil/water/fish (-)
f5=fish consumption (kg/person.day) 0,014
Breathing xfi=a6.f6-y xg=rate through inhalatin (mg/person.day) < 10-7
a6=transfer coefficient soil/air and dilution (kg/np)
f5=inhalation volume (m^/person.day) 12
Total *t=cty xt=50% of ADI for soil routes (mg/person.day) 0,064
ci=overall coefficient (kg/person.day) 0,09
y=soil concentration limit (mg/kg) 0,36
remaining 50% allocated to other intakes such
as smoking and industrial exposures. For
Cd the corresponding soil concentration was
calculated to be 0,36 mg/kg which value is
slightly below maximum observed reference
soil concentrations.
The effects of soil contamination on the
crop growing function of the soil was
extensively evaluated (LAC, 1985) and signal
values or criteria were developed above
which a crop yield reduction could take place
or whereby the human health through crop
consumption could be harmed. The values
for the different elements are Cd: 0,5-1,0
mg/kg (human consumptive), Cu: 30 mg/kg
(yield reduction), Pb: 100-150 mg/kg
(human consumption/yield reduction), Hg:2
mg/kg (human consumption); Zn: 100-350
mg/kg (yield reduction), hi which the lowest
value in the range applies to sandy soil and
the highest value for clay and organic soils.
These values are in agreement with the
reference values developed earlier.
466
-------
SOIL QUALITY DETERIORATION AND
REMEDIATION
The proposed reference values
representing the upper limits of the currently
uncontaminated soils (with 2.5% excellance)
are expected to be exceeded in the future if
input through sludge and compost application
and fecal fertilizers is not greatly restricted
(Table 5.) Steps to restrict these diffuse
inputs are currently being taken.
The number of soils classified as
contaminated by hazardous waste and point
sources will increase because the reference
values are lower than the earlier established
"A" values used to designate the sites. Most
remedial technologies developed in the
Netherlands that use separation, washing and
leaching techniques have generally been able
to reduce the inorganic elements to the "B"
values shown in Figure 1. However the "A"
value or the above discussed reference values
have generally not been met, indicating that
the use of the cleaned-up soil is not
unrestricted and is still subject to ICM
criteria.
CONCLUSION
The present study established reference
values for uncontaminated soils in relation to
its clay and organic matter content. These
reference values are to be used to designate
soils that are contaminated by hazardous
waste and releases from point sources. In
addition, they will be considered as cleanup
goals (but not as legal standards) to be
reached by soil remediation techniques. The
limited dose-effect relationships for the
different soil functions indicate levels
comparable to the reference values.
Reference values for organic substances (27
chlorinated hydrocarbons, 13 polycydic
aromatics and total alkanes) were also
developed in relation to the organic matter
content of the soil. Because of the limited
data and numerous assumptions, the results
are presented elsewhere (TCB, 1986).
TABLE 5. Input and Output of elements on agricultural soil
input (g/ha/jr) '• output (g/ha/jr)
_. _ Period in which
He- Depo- Sludge & Fecal Plant Concentration ,
Zn
Cu
Pb
Cr
Ni
Cd
Hg
400
60
100
4
10
3
0,2
4000
1200
1000
1000
200
10
10
1080
625
20
--
35
2
0,12
300-500
20-70
30-60
10-15
45-70
2 ,
0,2
100-500
30-1650
1-80
1-10
10-30
0,3-8
0,2 - 1,5
50-60
25-30
120-160
190
500-700
120-300
45-50
*Period in which concentration in top 20 cm doubles from half of reference value to full
reference value for standard soil.
REFERENCES
Biemond, C "The use of the soil," in "Handbook for Environmental Mangement" Edit."
VandenBerg C. et al., Vermande Zonen/Samson Publ. Alphen aan de Ryn( 1978).
Breeuwsma A "Background values for metals in pleistocene sandy soils; contribution to
TCB task force" Institute for Soil Cartography, Wageningen (1986).
EC: European Community "Water quality standards for drinking water, EC directive" EC
Publications Journal, L229-11(1980).
467
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Edelman T "Background concentrations of a number of inorganic and organic substances in
dutch soil," Ministry of Housing, Physical Planning and Environment, Soil Protection
Series 34, Governmental Printing Office, The Hague (1984).
LAC, Agricultural Advisory Committee on Environmentally Critical Substances "Signal
values for concentration of environmentally critical substances in the soil with respect to
agricultural use of polluted soil, Minsterly of Agriculture The Hague (1985).
Moen JET, Cornet JP, Evers, CWA "Soil protection and remedial actions: criteria for
decision making and standarization of requirements" in "Contaminated Soil" Ed. Assihk
JW and VandenBrink WJ, Martinus Nyhoff Publ. Dordrecht (1986)
Nypels ETHM "Opening Speech Soil Quality Symposium," Minister of Housing, Physical
Planning and Environment, The Hague (1986).
Rivm, State Insitute for Public Health and Environmental Hygiene "Monitoring network
for rain water, summary and statistical evaluation of the analytical results"
Bilthoven/Leidschendam (1984).
Salomons W "Preliminary baseline values for Cd, Zn, Ni, Pb, Cu, and Cr in Dutch
sediments" Report R1703, Hydraulics Laboratory, Delft (1983).
TCB: Technical Commission on Soil Protection "Recommendation for Soil Quality"
Ministry of Housing, Physical Planning and Environment, The Hague (1986).
VanDuyvenbooden W, Gast LFL, Taat T "Country wide groundwater monitoring network,
final report of the settup phase" Ministry of Housing, Physical Planning and Environment,
Soil Protection Series 46A, The Hague, Governmental Printing Office (1984).
VROM: Ministry of Housing, Physical Planning and Environment" Is our soil the
forgotten son," The Hague, (1986).
Van Driel W. and Smile K. W. "Heavy metal contents of dutch arable soils" Landwirtsch.
Forsch. Sonderh. 2& 305 - 313 (1982)
Van Heck B and Wassenberg W "Groundwater contamination from industrial activity" M.
Sc thesis, University of Utrecht (1984).
Van Wynen JH "Evaluation of the health risk in a case of soil pollution (Volgermeer)"
Tydschr. Soc. Geneesk. £0_ (1982).
Verwey GCG andLuiten JA "Significance and use of reference framework, concentration
measurements and characteristics of substances in the evaluation of soil contamination"
RIVM, Report 840224002, Leidschendam/Bilthoven (1984)
Wiersma D, Van Goor BJ, VanderVeen NG "Inventory of cadmium, lead, mercury and
arsenic in Dutch crops and related soils" Institute for Soil Fertility, Report 8-85, Haren
(1985).
468
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Land Treatment of an Oily Waste - Degradation, Immobilization
and Bioaccumulatfon
Raymond C. Loehr
Civil Engineering Department
The University of Texas
Austin, TX 78712
John H. Martin, Jr.
Agricultural Engineering
Department .
Cornell University
Ithaca, New York 14853
ABSTRACT
Edward F. Neuhauser
Niagara Mohawk Power
Corporation
Syracuse, NY 13202
Land treatment of ,an industrial oily waste was investigated to determine the loss and immobi-
lization of waste constituents and the impact of the waste and the application process on soil biota. The
waste was applied to field plots of a moderately permeable silt loam in New York. The plots consisted of
four replicates of natural controls, rototilled controls, and each application rate. Wastes were applied in
06/82,10/82, and 06/83 and at seven waste application rates that ranged from 0.09% to 5.25% oil and
grease in the zone of incorporation.
The applied wastes increased the pH and volatile matter of the soils. The half-life of the total oil
and grease ranged from about 260 to about 400 days. Not all of the applied oil was lost. The refractory
fraction did not appear to adversely affect the soil biota. Napthalenes, alkanes and specific aromatics
were rapidly lost from the soil. The half-life of these compounds generally was less than 30 days.
The waste applications increased the metal concentration in the upper 15 cm of the soil. Except
for sodium, all of the metals were immobilized. These wastes did not cause any unexpected
bioaccumulation of metals in the earthworms. The earthworms did not accumulate napthalenes, alkanes,
or specific aromatics that were in the applied waste. Rototilling and waste application initially reduced
the numbers and biomass of earthworms in the field plots. The soil biota were able to recover from these
perturbations.
INTRODUCTION
Land treatment is a managed waste
treatment and ultimate disposal process that in-
volves the controlled application of a waste to a
soil. The wastes are applied to the surface or
mixed with the upper zone (0-1 ft. (0-0.3 m)) of
soil. Land treatment: (a) results in the biological
degradation of organics and the immobilization of
inorganic waste constituents, and (b) utilizes the
assimilative capacity of the soil.
Land treatment has been used as a waste
management technology by petroleum refineries in
the United States for more than 25 years, as well
as by other industries. The major concerns when
land treatment is used for industrial wastes are
the transformations, transport and fate of poten-
tially toxic metals and organics that may be in the
wastes.
As identified in the Resource Conservation
and Recovery Act (RCRA), land disposal methods
are to be protective of human health and the envi-
ronment. The factors to be taken into account in
assessing such protection are the persistence,
toxicity, mobility and propensity to bioaccumulate
hazardous wastes and their constituents.
469
-------
Except as part of organic degradation, the
soil biota rarely have been included in any land
treatment system evaluations. However, the top
layer of soil contains myriad microbes and
invertebrates that degrade and transform the ap-
plied organics. In the terrestrial food chain, earth-
worms represent one of the first levels of bioac-
cumulation that can occur when wastes are ap-
plied to the land. Therefore, in this study earth-
worms were used as a test organism for deter-
mining the impact of industrial waste on soil biota
when land treatment is used for such wastes.
PURPOSE
The purpose of this project was to deter-
mine: (a) the loss and immobilization of con-
stituents of an oily waste when the waste was
applied to the soil at different application rates,
(b) the impact of the waste and the application
process on earthworms, and (c) the general as-
similative capacity of a soil when industrial
wastes are land applied.
APPROACH
Cooperation - This project was a cooper-
ative agreement between Cornell University and
the Robert S. Kerr Environmental Research Labo-
ratory (RSKERL) of the Environmental Protection
Agency (EPA). The research was conducted in
laboratories of the Department of Agricultural En-
gineering, Cornell University, and on land adjacent
to the Cornell campus.
Wastes -- The wastes were obtained from
a site in Oklahoma with the help of RSKERL per-
sonnel. The wastes were black, viscous, and col-
lected from the bottom of a lagoon used to store
wastes from oil refineries. The wastes were ap-
plied to the field plots at different application
rates. Samples of the wastes were analyzed be-
fore each application date, and the oil data used to
determine the volumes of waste to be added to
achieve the desired loading rates.
These oily wastes had been contained in
the lagoon for several years before the required
quantities were removed and transported to the
field site for application. Many volatile compounds
may have been lost while the wastes were in the
lagoon.
Field Site ~ The site used for application
of the waste was an old field in Tompkins County,
New York. It had not been used for agricultural
purposes and had not received lime, fertilizer, pes-
ticides or herbicides for over 10 years before its
use in this project. The soil at the site was a
Rhinebeck silt loam. The soil was moderately
permeable, had a cation exchange capacity of
24.8, and exists on nearly level to moderate slopes
in glacial lake areas.
The field site consisted of 20 plots, 4 me-
ters by 4 meters, with 4 meters of border area
surrounding each plot. Natural and rototilled con-
trols were used at the site. Four replications were
made for each waste application rate and type of
control. All plots were mowed before each waste
application. All plots, except the natural controls,
were rototilled after each application of the waste.
The four rototilled control plots had no waste ap-
plied but were rototilled. The four natural control
plots had no rototilling or waste applied and were
used to separate the effect of the rototilling and
the waste applications. The applied wastes were
distributed over the plot surface as uniformly as
possible and were rototilled into the soil such that
the zone of incorporation (ZOI) was the top six
inches (15 cm).
Each test plot (16 m2) was marked with
corner stakes to permit placement of a grid to de-
fine 400,20 cm by 20 cm sampling subplots. Three
different subplots were sampled on each sampling
date to determine changes in ZOI characteristics
and in earthworm populations. To eliminate edge
effects, no edge subplots were sampled. The sub-
plots that were sampled were determined using a
random number table. Thus, different sampling lo-
cations were used at each plot each time samples
were taken. No subplot was sampled twice during
the study. An elevated plank platform was used
for sampling so that the plots were not disturbed
or contaminated while the samples were taken.
470
-------
Natural vegetation such as grass was al-
lowed to grow on the plots after the waste appli-
cations. Native grasses did re-establish them-
selves on all of the plots in the months after the
wastes were applied.
Soil cores were taken from each plot at
approximately monthly intervals except during the
winter. Hand sorting was used to determine
earthworm numbers and biomass from each core.
Before the characteristics of the ZOI were mea-
sured, the cores from each plot were composited.
Residual soil was returned to the plots and used to
fill in the core holes.
Analytical Procedures ~ Metals and cer-
tain organics in the waste, soil and earthworm
samples were analyzed by personnel at RSKERL,
using ICAP, GC and GC/MS procedures as ap-
propriate. Cornell personnel analyzed the waste
and soil samples for more routine parameters us-
ing Standard Methods or comparable procedures.
Special Studies - Two special studies
were conducted to determine the variability in the
characteristics of the ZOI and the precision and
accuracy of the analytical method used for oil and
grease when used with soil samples. The spatial
variability study identified the extent to which the
variability of the data was due to the non-ho-
mogeneity of waste application and rototilling.
The results of these studies have been published
(1,2).
Waste Application - Table 1 identifies the
application rates, dates of application and the
plots that received the wastes. One set of plots
received wastes three times at progressively
larger rates. Another set received wastes twice.
The effect of seven application rates, covering
those likely to be used under actual field conditions,
was evaluated.
Only the indigenous nutrients and trace el-
ements in the soil and the waste were available to
the micro- and macoorganisms as the wastes
were degraded. No fertilizers or other amend-
ments were added to the plots. The plots were
only cultivated (rototilled) immediately before and
after the wastes were applied. No subsequent
cultivation occurred to aerate the ZOI. This ap-
proach was taken in order to approximate the
changes that would occur under conservative and
nonoptimum conditions such as when single or
highly intermittent waste applications are
administered or when a spill occurs. The approach
also caused one less variable, the frequency and
type of aeration (tilling) to be included in the study.
TABLE 1 -- FIELD PLOT APPLICATION RATES
Average
Date of Waste
Application
June 1982
October 1982
June 1983
Oil Application
Rate (kg oil/m2)
0.17
0.34
0.68
1.46
2.74
4.55
9.5
Field Plot
Number*
5,6,12,18
4,10,11,17
2,8,14,20
5,6,12,18
4,10,11,17
2,8,14,20
5, 6, 12, 18
+ Plots 1,7,13 and 19 were natural controls and plots 3,9,15 and 16 were rototiiled
controls.
471
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RESULTS
The pH of the plots that received the high
applications of the oil waste increased. The in-
crease was pronounced for the plots that received
the very high applications in 06/83 (Figure 1). In
these plots, the soil pH increased by more than one
unit from below 6.0 to about 7.0 After the waste
applications, the pH stayed at above background
levels for the remainder of the study. An evalua-
tion in April, 1986, almost three years after the
last application, indicated the pH in the very high
application rate plots continued to remain higher
than the controls and had a value of 6.7.
The volatile matter in the soil was in-
creased by applying waste. Until the larger waste
applications in 10/82, the volatile matter in all the
plots was about 9% of the soil on a moisture free
basis. After the 10/82 application, the volatile
matter in the plots increased to 10 to 11%. After
the application in 06/83, the volatile matter in the
very high application plots was 14 to 15%. In
April, 1986, volatile matter in the very high plots
was 12.8%, indicating that there had been little
loss of the residual organic matter in three years.
The loss that did occur represents natural degra-
dation processes.
With time, the concentration of oil and
grease in the soil decreased. The pattern of loss is
illustrated in Figure 2 for the oil and grease in the
high application plots. However, the applied oil and
grease was not lost completely. After each
waste application, a new apparent background
concentration in the respective plots resulted.
It was impossible to correlate statistically
the oil and grease losses to the field plot soil
temperatures. Any effect due to temperature
was masked by factors such as the variability in
the oil and grease data, differences in soil moisture
as the soil temperature changed, and differing oil
and grease compounds in the soil during the study.
The immobilization of metals in the soil
was analyzed by comparing the metal concentra-
tions of subsoil samples from the 15 to 30 cm
depth taken in 10/83. The concentrations of Al,
Cd, Ca, Cr, Cu, Fe, Pb, Mg, Mn, Ni, K, Na, Ti,
Va and Zn were analyzed statistically to de-
termine if the deeper soils of the controls and the
waste application plots had differing metal
concentrations. The analysis indicated that sodi-
um was the only metal with a significantly differ-
ent concentration in the 15 to 30 cm depth be-
tween the control plots and any waste application
plot. That difference only occurred for sodium in
the soil of the very high plots.
Soil samples from the plots were taken at
intervals of one month or more to determine the
loss patterns of specific organics. The samples
were extracted with methylene chloride and the
extracts analyzed for CQ to C26 alkanes,
napthalenes, and aromatics such as fluorene, an-
thracene, phenanthrene and pyrene.
The half-life of organics applied to the soil
varied. The loss of specific organics (napthalenes,
alkanes, and certain aromatics) was rapid, espe-
cially in the warmer months (Table 2). The hajf-
life of these compounds was generally less than 30
days. In comparison, the half-life of the total oil
and grease in the field plots ranged from about 260
to about 400 days.
All of the applied organics were not lost
from the soil during the study. The separation and
identification procedures used were not able to
identify the type or structure of the residual
organics that remained in the soil at the end of the
study. However, bas.ed on laboratory studies us-
ing soil from the field plots and the fact that
earthworms could repopulate the soil of the plots
receiving the wastes, the organics remaining in the
soil did not appear to result in a permanent ad-
verse impact to the soil biota.
The application of the wastes had definite
effects on the earthworm numbers and biomass in
the field plots, due to both the rototilling and the
immediate impact of the waste. The earthworms
were decreased by the rototilling and even more so
472
-------
TABLE 2 -- LOSS OF ORGANIC COMPOUNDS FROM FIELD PLOTS
Compound
Napthalene
2-methyl napthalene
1-methyl napthalene
1,3-dimethyl napthalene
2,3-dimethyl napthalene
Ci2 Alkane
Average
Half-Life
(Days)
R*
18
12
8
10
13
Compound
C-|4 alkane
Ruorene
Anthracene
1-methyl-phenanthrene
Pyrene
Average
Half-Life
(Days)
10
13
12
R
77
10
*rapid, loss to below detectable limits occurred in less than one month after application
by the wastes. However, with time, earthworms
did repopulate the field plots (Figure 3). Evaluation
in April 1986 showed a dramatic increase in
earthworm numbers and biomass in all the plots,
and especially in the very high application rate
plots. The project results indicate that these soil
biota can recover from the addition of oily wastes.
The earthworms in the plots accumulated
cadmium, potassium, sodium and zinc. Potassium
and sodium are of physiological but not environ-
mental importance in terms of bioaccumulation.
The cadmium that accumulated in the earthworm
tissue came more from the background cadmium in
the soil than from the cadmium in the applied
waste, since the cadmium bioaccumulated at
comparably high levels in the worms from the con-
trol plots. A comparison of the data from the
peer-reviewed literature indicated that the land
application of these oily wastes did not cause any
abnormal or unexpected bioaccumulation of metals
in earthworms.
Earthworm samples were analyzed for
the same organic compounds that were determined
for the soil extracts (alkanes and certain aro-
matics). None of these compounds were found in
the earthworm methylene chloride extracts at
concentrations greater than the detection limits.
CONCLUSIONS
The results indicated that the soil has the
capacity to treat wastes such as those used in
this study. Many of the organics in the applied
waste were removed (lost) and the metals were
immobilized when the wastes were applied to the
soil intermittently and at varied rates. The soil
cultivation method (rototilling) and the applied
waste had an immediate adverse impact on the
earthworms, but they recovered with time. A
fraction of the applied oil and grease was not re-
moved during the study. The remaining organics
and the metals did not appear to have any
permanent adverse effect on the soil biota.
The study indicated that soil biota can re-
cover from intermittent applications of an oily
waste. With time, the numbers and mass of
earthworms in the plots to which the wastes were
applied can become similar to those in the control
plots. The land application of these wastes did not
have an irreversible, adverse impact on the
earthworms.
ACKNOWLEDGEMENTS
The assistance of staff and students at
Cornell University, of the EPA Project Officer,
Mr. John E. Matthews, and of the personnel at
473
-------
RSKERL who analyzed the samples for metals
and organics is gratefully appreciated.
The complete project report is available
and can be obtained from the National Technical
Information Service, Springfield, VA, 22161 (Order
No. PB-166353/AS).
REFERENCES
1. Martin, J.H., Jr., and R.C. Loehr, "Determination
of the Oil Content of Soils," Hazardous and Indus-
trial Solid Waste Testing: Fourth Symposium,
ASTM STP 886, J.K. Petros, Jr., W.J. Lacy and
R.A. Conway, Editors, American Society for
Testing and Materials, Philadelphia, 1986, pp. 7-14.
2. Loehr, R.C., Martin, J.H., Jr., and E.F. Neuhaus-
er, "Spatial Variations of Characteristics in the
Zone of Incorporation at an Industrial Solid Waste
Land Treatment Site," Hazardous and Industrial
Solid Waste Testing: Fourth Symposium, ASTM
STP 886, J.K. Petros, Jr., W.J. Lacy and R.A.
Conway, Editors, American Society for Testing
and Materials, Philadelphia, 1986, pp. 285-297.
DISCLAIMER
Although the research described in this article has been funded wholly or in part by USEPA, the
article has not been subject to Agency review and therefore does not necessarily reflect views of the
Agency and no endorsement should be inferred.
474
-------
8.0
7.0
X
a
O 6.0
w
5.0
VERY HIGH
WASTE
APPLICATION
PLOTS 5,6,12 AND 18
NATURAL CONTROL
J 1 1 1 1 1 « t t
»— J
«
MAMJJASOND J F MA M J 4
'1983 >• < 1984 >
FIGURE 1
pH of the Soil in Several of the Field Plots
o
M
O
O
30
25
o
2 20
w
o>
15
10
WASTE
APPLICATION
AVERAGE
L
STANDARD
DEVIATION
HIGH APPLICATION RATE
ONDJFMAMJJASONDJ FMAMJJ
» -• 1983 »• < • 1984'
FIGURE 2
Oil and Grease Concentrations in the Soil of Field Plots
2,8,14 and 20
475
-------
200
160
• Natural control
^Rototilled control
D Low
« Medium
OHigh
A Very high
M
en
w
i
,0
15
o
Ul
120
Very high waste application
JJASONDJFMAMJJASO
FIGURE 3
Earthworm Biomass in the ZOI of the Field Plots
476
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THE USE OF CONTAMINATED MATERIAL FOR THE
CREATION OF NEW HOUSING LAND AT THAMESMEAD,
LONDON.
George W. Lowe .
London Scientific Services
The County Hall
London SE1 7PB.
ABSTRACT
Re-development of the Royal Arsenal in Woolwich, London, to form the new town
of Thamesmead has required the reclamation of 1000 acres of derelict industrial land
lying at a considerable distance from disposal facilities able to receive contaminated
material of the quantity arising from the development. This could have caused serious
financial and logistical problems if advantage had not been taken of new river wall
construction associated with the Thames Barrier and the London Flood prevention
scheme. The river wall was constructed in the bed of the River Thames enclosing a
large area of silt normally exposed at low tide.
Space formed between the new river wall and the old river embankment provided
an opportunity to create new land using excavated material from construction sites
known to be polluted by industrial waste from the Arsenal. Licences were granted for
two disposal facilities'to receive a total of 800,000 cubic metres of contaminated soil.
The first facility containing 350,000 m3 is now ready for new housing
development. On completion of filling and prior to final consolidation by surcharging,
the land was investigated as if it were an existing contaminated site. The data
obtained demonstrated a remarkable amelioration of the contamination due to mixing
and consolidation techniques adopted during deposition and the result is new housing
land requring little remediation to make it safe. The savings made in disposal costs
are impossible to calculate at the present time but they are of the order of 5 million
pounds Stirling.
INTRODUCTION
Background - Development of
Contaminated Land.
The decision to make use of
contaminated material to create new
housing land at Thamesmead did not
form part of the original thinking when
development of the new town was
envisaged. At that time, there was little
to suggest that new building would be
seriously effected by ground conditions
arising from industrial contamination,
although there was some concern about
mislaid explosives and unexploded bombs
remaining in the ground from wartime
air attacks.
Ground pollution problems began
to manifest themselves in 1975 when
advance civil engineering work started at
the western extremity of the
development where major armaments
manufacturing and testing facilities had
been concentrated. At the same time,
problems associated with re-development
of contaminated land began to achieve a
477
-------
prominence in London on a scale not
previously experienced. This was mainly
due to increasing demand for new
development land at a time of serious
land shortage in the inner city areas.
This in turn led to the re-use of derelict
land remaining from the decline of
traditional and often noxious industries,
rationalisation of transportation systems
and changing patterns of energy demand
and provision. Sites such as these had
never been much in demand for re-
development except in locations where
site values were so high as to overide
the financial significance of
reclamation.
In common with the controlling
public authority for Thamesmead, the
developers of contaminated land in
London were confronted with the need
to arrange safe disposal of surplus
excavated material arising from civil
engineering and general construction
work. The Control of Pollution Act
1974 was only just beginning to have an
effect, licencing procedures for disposal
sites were in their early stages and not
fully understood, and the construction
industry had yet to fully grasp the
significance of emerging regulations.
Most importantly, it soon began to
emerge that regardless of transportation
costs, available disposal options were
likely to be severely restricted due to
lack of capacity. (1)
These problems compelled
developers and contractors to address
their attention to the disposal of
excavated waste from their sites as a
fundamental part of their operations,
rather than dealing with it as a
consequence of construction to- be
relegated to sub- contractors with the
lowest possible transportation rates,
dubious disposal arrangements and a
commensurate disregard for the
environment.
The scale of the operation at
Thamesmead demanded an approach to
disposal of contaminated material which
would take into account ever increasing
costs of transportation to limited
disposal facilities, risks to the
environment generally and the
inconvenience to newly occupied
households. Additionally, the perceived
social impact of long term, large scale
development likely to be felt in the
surrounding areas prompted Local
Authorities to place restriction on the
routes and movement of heavy vehicles
carrying materials to and from the site.
Fortunately, the Planning and
Design teams for Thamesmead were
able to take advantage of
comprehensive project management
with a direct line to policy making
committees of the Greater London
Council under whose auspices the
development of the town was taking
place. Opportunities thus arose to
profit from circumstances both external
and apparently unrelated to
Thamesmead and find a very successful
solution in financial and environmental
terms to a seemingly intractable
problem. A more positive response to
re-cycling proposals was also beginning
to emerge which was also very useful.
The London Flood Prevention Scheme.
Thamesmead has a frontage onto
the River Thames of approximately 3i
miles (5.6 KM) and in consequence has
been significantly influenced in its plan
form by major civil engineering works
associated with the London flood
prevention scheme. The principle
component of the scheme is the Thames
Barrier which was completed in 1985
and was at that time, the world's largest
movable flood barrier. Downstream, the
embankments of the river have been
raised to accommodate tidal surges
originating in the North Sea. Where
appropriate, new stretches of river wall
have been constructed entirely, and
there is a section of this at Thamesmead
approximately 1 mile (1.6KM) in length.
478
-------
Studies of the flow characteristics
of the Thames indicated that the ideal
location for this section of the river
wall was in the bed of the river itself,
sited to enclose a section of foreshore
composed of deep, hazardous silt which
became exposed at low tide. The
maximum distance of the new wall from
the original embankment is
approximately 150 metres and although
this reduces to zero at its conjunctions
with the bank at each end, the crescent
shaped area of re-claimed river bed thus
formed is approximately 40 acres in
extent. This presented an opportunity
for the provision of major facilities at
Thamesmead to serve the internal flood
control system of the town itself and
provide two disposal sites for
contaminated material arising from
construction works.
PURPOSE
On discovery of ground pollution
at Thamesmead and knowing the
difficulties encountered with re-
development of contaminated sites
elsewhere, the Planning and Design
Teams were instructed by the Council to
undertake initial studies to determine
the geographical extent of the problem,
the implications it would have on
development, and in the longer term to
undertake site by site investigations
leading to remedial action. (2). A
specialist team was established
composed primarily of medical,
scientific and technical officers who
were soon to encounter the difficulty of
making an overall assessment of ground
pollution when the previous land use was
almost totally classified (no
information!).
APPROACH
An essential requirement of the
team was to make an assessment of the
overall, physical influence of ground
contamination on the development form
and programme with particular emphasis
on costs arising from increased muck
shifting and disposal. Following
extensive calculations based on a
number of area planning scenarios it
became very clear that the cost and the
impact on the environment of exporting
possibly li million cubic metres of
contaminated material to out-county
disposal facilities was totally
unacceptable. Other enquiries had also
established that even if the
environmental impact question was set
aside, the capacity of exisiting disposal
sites was too uncertain to guarantee
their availability in the long term.
Under the circumstances, disposal
within the confines of Thamesmead
became the only viable alternative, and
it was fortunate for the development as
a whole that the opportunity to use the
spaces being created by the construction
of the new river wall would be turned to
positive advantage.
Procedures
Before the disposal facilities could
be established, a number of difficulties
had to be overcome both in practical
and managerial terms. Not least of
these was the provision of sufficient
data to obtain a licence under the
recently promulgated-Control of
Pollution Act before the full nature and
extent of ground pollution had been
established. Another was to lay down
criteria for control and management of
the disposal facilities so that on
completion of filling and consolidation
they would provide development land
whose general environmental condition
was no worse than that of contaminated
sites elsewhere in Thamesmead prior to
rehabilitation.
A period of approximately 15
months was seen to be available for
extensive site investigation work before
programmed development of
contaminated land created the need for
disposal of substantial quantities of
479
-------
excavated material. During this time,
data from site investigation provided
enough information for the site
licencing authorities in the GLC to
assess levels of those substances
forming the greater part of the
contamination at Thamesmead which
could be included in the mass of disposal
material.
The conditions of the disposal
licence also demanded a form of
management for the facilities which was
not compatible with normal construction
contract procedures, but was achieved
by placing site supervision,
administrative control and the
programming of filling in the hands of
the Thamesmead management teams.
Controls
Probably, the most significant
factor in the operational control of the
disposal facilities was the ruling that no
material would be accepted unless
removed from sites which had been
subject to full investigation. All
investigation data was subject to
scrutiny by a multi-disciplinery panel of
specialists including those concerned
with assessement of hazardous waste
and site licencing procedures. By these
means, the disposal facilities only
received material from sites whose
general level of contaminaton was
acceptable under the terms of the
licence. This to some extent was to
influence development form.
Physical Influences
The major physical influence on
the eventual condition of the facility
was the condition introduced into the
licence for ground consolidation
purposes which demanded that material
was spread, levelled and compacted in
layers of 9 to 12 inches (225- 300mm)
deep. In practice, this meant that one
vehicle load of say 20 cubic metres
would be spread over an area not less
than 80 square metres in area. The
value of mixing and dilution of the
material under these circumstances is
clearly very great especially when it is
realised from the examination of the
available data that a significant
proportion of excavated material from
polluted sites may not be seriously
contaminated.
PROBLEMS ENCOUNTERED.
The majority of the problems
encountered arose from programme
fluctuations when filling the first
facility, (4J/4K). As this meant that no
material would be received fpr disposal
for several weeks on end, the work force
and heavy plant were deployed
elsewhere. By direction of the Councils
Medical Adviser, at these times the
whole area was covered by a thin layer
of clean soil to avoid contaminated dust
being blown into surrounding areas in
dry periods. This however was
advantageous in further dilution of the
contaminated material in the fill.
It was envisaged that in the long
term, contaminated leachate might exit
to the river via the new river wall and
that there may be problems arising from
corrosion of steel tie rods and raking
piles forming part of the rival wall
construction.
Engineering and scientific opinion
based on analytical data, and extensive
tests carried out earlier to determine
the geological and hydrological
character of the site discounted both
possibilities. Nonetheless, heavy
coatings of bituminous protection were
applied to tie rods in the consolidated
backing to the main river wall
construction.
The backing of heavily
consolidated material and the steel
sheet piling plus reinforced concrete
structure of the river wall taken down
to the base of natural hard chalk is
480
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TABLE 1
Licence Limit Mean
Cadmium
Copper
Mercury
Nickel
Lead
Zinc
Cyanide
Toluene Extract
Sulphide
Thiocyanate
Ferri-Ferro Cyanide
Arsenic
20
1500
10
1000
2000
2000
100
1%
250
200
2000
150
1.07
532.20
1.46
85.70
877.80
870.70
2.98
0.24%
2.64
50.00
100.00
20.29
Total
200
200
200
200
200
200
200
200
200
6
6
200
Unless otherwise stated, all results are expressed as parts per million, i.e mg/kg dry
soil. Please note, 6 samples only were analysed for Thiocyanate and Ferri-Ferro
Cyanide because total cyanide determinations produced only 6 results sufficiently
significant to warrant analysis for complexed cyanides (3).
considered virtually impermeable to
leachate.
RESULTS
When facility 4J/4K was
completely filled, a cover of soil was
placed overall and seeded to provide a
temporary surface pending surcharging
of the site to accelerate consolidation.
Prior to this, the site was subject to
investigation as if it were a parcel of
newly acquired land with a potential
contamination problem. The object of
this was twofold; the first to determine
the general level of contamination in
the body of the site in order to assess
the effectiveness of disposal control
procedures, the second being to aid the
more important evaluation of the long
term health hazards of the facility with
a view to its eventual development as
housing land. Additionally, boreholes
were sunk through the fill to investigate
the possibility of methane gas being
generated in residual organic matter in
the remaining river silt at the base of
the facility.
Effectiveness of disposal methods.
The procedures for control of
disposal in 4J/4K and the specified
compaction methods had a diluting
effect on the fill which had not been
anticipated. Within a selected group of
contaminants comparison of the mean
values calculated from the analytical
data with the limits imposed by the
disposal licence indicates (so far as such
comparisons are valid) a very
satisfactory outcome which also served
to highlight the possibility of using
traditional civil engineering techniques
for in-situ rehabilition of contaminated
land.
A comparative table showing
mean values for contaminants within the
site and licence limits is set out in Table
1. Twenty five trial pits were dug to a,
depth of 6.00m and samples taken at
0.15, 0.50, 1.00, 2.00, 3.00, 4.00, 5.00
and 6.00 m below the surface producing
200 samples in all.
Disposal site into housing land
The transition of 4J/4K into
housing land was accomplished with far
less difficulty than was thought possible
when the project was embarked upon.
The overall level of pollution was found
to be such as to require much less
remedial work than those sites from
481
-------
which the material had been removed in
the first instance. In consequence, it
was recommended that only 0.50 metres
of clean imported capping material be
placed over the whole site to make it
suitable for housing development.
The site will be subjected to re-
investigation when the final layout of
the housing is known and regular
monitoring will be undertaken over a
period of 5 years after building is
completed. This procedure is not
peculiar to 4J/4K, but is part of an
overall monitoring policy for
Thamesmead agreed with the local
authority.
Several years will elapse between
completion of the disposal area filling
and its redevelopment for housing
purposes. Monitoring is expected to
reinforce experience elsewhere at
Thamesmead which has shown that
vertical upward migration of
contaminants via barrier layers does not
take place. Additionally, the depth of
cover will be augmented as necessary to
avoid disturbance by householders.
The value of the exercise in
financial terms is probably impossible to
quantify due to the influence of
changing land values at Thamesmead
attributable to other factors, but it is
known that actual cost savings in
creating new land out of re-cycled,
valueless material will not be less than
£5 million. The true worth of the asset
has also been much enhanced by the
knowledge gained in creating it, in that
it has been found that major disturbance
and localised re-distribution of
contaminated material on two other
major sites has lead to significant
reductions in the level of remedial
works needed to make them safe.
ACKNOWLEDGEMENTS
The officers of the 'Inter
Departmental Assessment Panel on
Contaminated Land' of the Greater
London Council. A uniquely experienced
body of people now disbanded since the
abolition of the G.L.C.
REFERENCES
1. Taylor G. and Lennon A., 'The
disposal of wastes arising from the
development of contaminated
land'.
London Waste Regulation
Authority. North Block, The
County Hall London SE1 7PB. U.K.
2. Lowe G.W. Investigation of Land
at Thamesmead and assesment of
remedial works to bring
contaminated land into beneficial
use. London Scientific Services,
Room 629, The County Hall,
London SE1 7PB U.K.
3. Carpenter R.J. A laboratory
report: Investigation into potential
contamination at Thamesmead
Area 4J/4K. for the G.L.C.,
London Scientific Services, Room
629, The County Hall, London SE1
7PB. U.K.
Disclaimer
The work in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency
and no official endorsement should be inferred.
482
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483
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w
E-
CO
r
94
s
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SECURE LANDFILL DESIGN/OPERATION
TO REDUCE LEACHATE AND CLOSURE COST
Randolph W. Rakoczynski, P.E.
Waste Resource Associates, Inc.
2576 Seneca Avenue
Niagara Falls, NY 14305
ABSTRACT
As permitting delays and increasing capital construction costs force
facility developers to consider landfill cells of increasingly larger
proportions, the tremendous volumes of leachate generated by these larger
facilities act to limit their size drastically. The "central low point"
design and method of operation which is presented allows these larger
facilities to be constructed and operated economically. Volumes of
leachate produced during the operating life of a central low point
fac ility are reduced by as much as 90-95% when compared with leachate
production using conventional landfill designs. Additionally, the
central low point design also allows the cost of closure funding to be
reduced by as much as 90-95%.
INTRODUCTION
As environmental regulations
governing the management of hazard-
ous waste have begun to focus more
closely on landfill facilities,
engineering design and methods of
operation for these facilities have
been forced to change. What may
have been standard operating
procedures a few years ago are now
out-moded methods which no longer
meet the minimum regulatory re-
quirements .
The Hazardous and Solid Waste
Amendments of 1984 (HSWA) and the
minimum technology requirements for
land disposal facilities this
statute has imposed have further
forced facility developers to
carefully reconsider their plans
and designs. The minimum technol-
ogy design requirements along with
the costs associated with closure
and post-closure of these facili-
ties and the unavailability of
non-sudden environmental impairment
liability coverage has all but
stalled the development of any new
landfill disposal facilities.
PURPOSE
In an attempt to stimulate the
development of the new facilities
which will be needed in order to
properly handle future volumes of
industrial hazardous waste genera-
tion and the residuals from "high
technology" treatment processes as
well as the enormous volumes
485
-------
of contaminated residues from
Superfund remedial action clean-ups
and surface impoundment closures, a
landfill design which cost-effec-
tively meets the minimum technology
requirements of HSWA has been
formulated.
In addition to meeting minimum
technical design requirements, the
landfill design incorporates
certain economies of scale and
other economic incentives attrac-
tive to prospective new facility
developers. Since the design
enables much larger tracts of
acreage to be developed, it avoids
the costly permitting delays
inherent in the sequential develop-
ment of individual landfill cells
which are much smaller in size but
when completed provide the identi-
cal total capacity of the larger
cell.
APPROACH
In developing larger tracts of
acreage into a landfill facility,
the design engineer is constrained
by the fact that as the landfill
acreage is increased, the volumes
of leachate produced from the
accumulation of rainfall also
increase. Oftentimes the increased
volumes of leachate associated with
larger landfills and the costs
involved with removing and treating
those volumes exceeds the savings
realized in the economies of scale
provided by construction of
larger facilities. The design
to be presented here circumvents
the problems of excess leachate
generation by larger landfills with
straight-forward, common sense
principles which are uniquely and
innovatively incorporated into the
design and operation of the faci-
lity.
The initial step in the
engineering design of any landfill
disposal facility is to maximize
the disposal capacity of the
proposed facility over the acreage
intended to be developed. The
primary constraints in maximizing
the capacity are usually the depth
to the seasonally-high water table
and the maximum height above grade
which local and/or state environ-
mental regulatory agencies will
permit for the proposed facility.
The desire to maximize disposal
facility capacity has in the past
led the design engineer to locate
the bottom "floor" of the landfill
the required d istance from the
seasonally-high water table with
minimal slopes on the bottom floor
(usually 1 percent-2 percent) to
promote drainage and leachate
collection. If slopes on the
bottom of the landfill are however
increased to on the order of
approximately 2-5 percent and the
floor is contoured to a centrally-
located, common low point, the
landfill facility can be designed
and operated to reduce the costs
associated with leachate removal/
treatment and closure of the
facility.
Liner System
The liner system employed in
the proposed landfill facility
design conforms to the minimum
technology requiranents put forth
by EPA as a result of HSWA.
Starting from the bottom of the
liner system, the liner system is
composed of the following compo-
nents:
« three (3) feet of recom-
pacted low permeability
soil liner (upper portion
of this layer is processed
486
-------
to remove stones and other
foreign debris);
• flexible membrane liner
(FML) of 30 mil high
density polyethylene
(HOPE);
• one (1) foot of granular
material (secondary lea-
chate collection and/or
leak detection zone);
• flexible membrane liner
(FML) of 80 mil high
density polyethylene
(HOPE);
• one (1) foot of granular
material (primary leachate
collection zone);
• geotextile fabric (for
filtration of leachate).
Limiting Active Disposal Area
In order to minimize the
amount of rainfall which is
accumulated as leachate, the active
area of the landfill facility must
be confined to an area surrounding
the common low point. An access
roadway can be constructed so that
heavy equipnient which will be used
to deposit waste transferred from
receiving facilities can easily
place waste in the active disposal
area. In addition to providing
access for heavy equipment, the
roadway also serves as the base of
a segregation berm(s) which separ-
ates the landfill facility into
individual cells which can each be
used to dispose of specific wastes
that would be incompatible if
disposed of together. The place-
ment of additional berms or separa-
tions within the individual cells
allows uncontaminated rainfall to
be kept from contacting the
deposited waste.
Waste Placement
Convent ional waste placement
procedures involve depositing
waste in lifts across the entire
floor of the landfill faci-
lity. Once a horizontal lift is
completed, the next lift is
begun. This method of waste
placement has two major drawbacks;
first the entire surface area of
the floor of the landfill is
subject to leachate generation and
secondly, closure of the facility
cannot begin until the entire
capacity of the landfill facility
is consumed.
In the common low point
design, waste placement is rele-
gated initially only to the active
disposal area surrounding the low
point. Once the elevation of the
waste reaches the level of the
access roadway/segregation berm,
the roadway is raised with the
placement of additional recompacted
low permeability soil. Waste
placement continues from the raised
roadway surface around the central
low point until its elevation again
reaches the road surface and the
roadway level is again raised.
This procedure continues until the
emplaced waste and roadway reach
their desired final elevations.
Waste deposition continues on the
inclined working face which has
been created in each cell.
Progressive Partial Closure
As the bottom toe of the slope
of the working face begins to
approach the temporary rainwater/
leachate separation berm or
device, the installation of the
final closure cap in those areas
that have reached final waste
elevation can proceed. The
components which comprise the final
closure cap are from bottom
to top:
487
-------
one (1) foot of
cover soil;
intermed iate
• two (2) feet of recompacted
low permeability soil;
• geotextile fabric;
• flexible membrane liner
(FML) of 80 mil h igh
density polyethylene
(HDPE)j
• geotextile fabric;
• two and one-half (2 1/2)
feet of soil;
• one-half (1/2) foot of
topsoil;
• vegetation.
As the installation of the
final closure cap is nearing
completion in those areas where
emplaced waste elevations have
reached desired levels, the tempor-
ary rainwater/leachate separation
berm or device is moved further
outward from the central low point
so that waste deposition on the
inclined working face can continue.
PROBLEMS MCOUNTERED
In formulating the design, the
following problem areas were
identified and addressed:
• emplaced waste stability
• installation of secondary
leachate or leak detection
zone (LDZ) on internal side
slopes of landfill peri-
meter
• access to the inclined
working face over the
final closure cap
• drainage of stormwater from
the final closure cap
• identification of the
source of any leaks de-
tected in the secondary
leachate collection zone.
Each of the problem areas was
resolved as follows:
Waste Stability •
In order to insure stability
of the final upper surface of waste
for final closure cap placement and
heavy equipment access, it was
determined emplaced waste had to
meet certain criteria. A minimum
angle of cohesion and load bearing
capacity must be provided. As part
of inbound quality control testing,
a minimum unconfined compressive
strength and absence of "free
liquid" must be confirmed for
wastes to be deposited directly
into the active disposal areas. If
either "free liquid" is present or
insufficient load bearing capacity
is provided, the waste must be
pre-treated using appropriate
chemical fixation/solidification
agents.
Sideslope LDZ
The granular material used in
the secondary leachate removal or
leak detection zone cannot be
placed on the angle required for
the internal sideslopes of the
landfill facility. Along the
internal landfill sideslopes, the
granular material was replaced with
a drainage net fabricated of high
density polyethylene.
Working Face Access
In order to allow heavy
equipment continued access to
488
-------
the working face for waste depos i-
tion, a temporary roadway must
be provided over the final closure
cap.
Closure Cap Drainage
Drainage conduits (clay tile)
are provided to direct closure cap
stormwater run-off to col Lection
channels around the landfill
perimeter.
Leak Identification
Inherent in the design is the
shortcoming that if the primary or
upper FML should leak and 1iquid is
detected in the secondary leachate
collection or leak detection zone,
the source of that leak cannot be
accurately identified. In a
large landfill facility of signifi-
cant acreage this represents
a problem with regard to any
attempt to undertake remedial
action to repair the primary or
upper FML. A leak detection
and identification system has been
provided in this central low
point design. A matrix of electri-
cal probes are placed within the
granular material that comprises
the secondary leachate collection
or leak detection zone. These
probes are monitored so that if a
leak occurs and leachate enters the
zone, the origin of that leak can
be identified.
RESULTS
The most important benefit
resulting from the landfill
design presented is the dramatic
reduction in both leachate genera-
ted during the operating life of
the facility and the volumes of
leachate which must be withdrawn
following the completion of clo-
sure. In conventional landfill
design and operation, completely
dewatering a closed landfill may
extend many years into the post-
closure care period of the faci-
lity. Until the closed facility is
completely dewatered, a head of
leachate exists within the landfill
which can potentially be a driving
force for contaminant migration in
the event of any liner deteriora-
tion or failure. The landfill
design and method of operation
which is proposed are successful in
limiting operational and post-clo-
sure leachate production because;
• active disposal area within
the facility is limited
during the operating
life;
• deposited waste leachate
generation is limited
primarily to the active
working face which is
inclined and minimizes
percolation of rainfall
down into the waste;
» final closure cap is
progressively installed in
increments which eliminates
percolation of rainfall
into the waste;
• bottom floor of the land-
fill has steeper slopes
which improve leachate
collection efficiency.
The economic analysis which
follows demonstrates the cost
savings realized with use of the
proposed design/method of operation
versus use of convent ional secure
landfill design/ operational
methods.
Economic Analysis
The following table presents a
489
-------
comparison of disposal capacity for
a conventional "flat" bottom design
and the "central low point" design
for a landfill which is 30-feet
deep. The "flat" bottom design
assumes floor slopes on the order
of 1-2 percent. The "central low
point" design assumes floor slopes
of on the order of 2-5 percent. No
mounding of the final closure cap
of the facility has been considered
in computing the disposal capaci-
ties listed, since the extent to
which mounding is allowed varies
considerably from state to state.
Landfill Size Disposal Capacity
Landfill Size Leachate Production
(acres) (cubic yards)
5.0
10.0
15.0
20.0
30.0
40.0
50.0
"Flat"
206,000
411,000
630,000
817,000
1,250,000
1,650,000
1,945,000
"Central Low
Point"
181,000
342,000
482,000
604,000
796,000
935,000
1,028,000
In order to compute the lea-
chate production volumes which are
presented in the following table, a
30-inch net annual rainfall minus
evaporation was used. It was
assumed that this net annual
rainfall was responsible for
leachate generation over the
intended operating life of the
facility. .The operating life was
computed by dividing disposal
capacity by a uniform annual waste
receipt volume of 100,000 cubic
yards.
(acres)
(millions
of gallons.]
"Flat" "Central Low
Point"
5.0
10.0
15.0
20.0
30.0
40.0
50.0
8.4
33.5
77.0
133.7
, 305.7
538.0
794.7
0.7
2.8
5.9
9.9
19.5
30.5
41.9
In computing leachate produc-
tion volumes for the "central
low point" design, it was assumed
that only one-tenth of the landfill
surface area would be in active use
at any point in time during the
operating life of the facility.
Landfill Size Closure Cost
(acres)
(millions
of dol]
"Flat" "Central
Poim
5.0
10.0
15.0
20.0
30.0
40.0
50.0
$0.5
$1.1
$2.1
$3.3
$7.4
$13.8
$24.1
$0.05
$0.1
$0.2
$0.3
$0.5
$0.8
$1.0
The above closure cost compari-
son was computed based on closure
490
-------
financial mechanism for assuring
closure must be in-place prior to
facility start-up, the closure
costs presented reflect a 10%
escalation factor over the full
term of the operating life of the
facility.
This escalation factor accounts
for the return on the closure fund
dollars which the facility owner/
operator would realize if those
dollars were not tied up in the
closure funding. The closure cost
funding for the "central low point"
design assumes closure of the
maximum one-tenth of landfill
surface area which is in active use
at any point in time.
By comparing the lost disposal
capacity for the "central low
point" design (valued at $100 per
cubic yard) with the savings in the
costs for removing/treating lea-
chate (estimated at $0.15 per
gallon) and the reduction in
closure cost funding, the following
graph shows clearly that as the
acreage of a proposed facility
begins to exceed 20 acres the
"central low point" design is
justified in lieu of the conven-
tional "flat" bottom design.
150-
loo —
DOLLARS
( x 10°)
ECONOMIC ANALYSIS OF CENTRAL LOW POINT LANDFILL DESIGN
.KEY_
REDUCTION IN CLOSURE
COST FUNDING
SAVINGS IN LEACHATE
TREATMENT COSTS
LOST DISPOSAL REVENUES
JDUE TO REDUCED CAPACITY
50-1
1O
15 2O
LANDFILL SIZE (ACRES)
\
I
50
491
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ACKNOWLEDGMENTS
The "central low point" design
is protected under a U.S. patent
which was recently issued and
was developed in conjunction with a
Part B Application compiled and
submitted on behalf of Sechan
Limestone Industries, Inc. (For-
tersville, PA).
John I. Rolfe, P.E. (Pegasus
Consultants, Niagara Falls,
NY) collaborated on certain selec-
ted portions of the design.
The leak detection system for
the central low point design was
developed by Electronetics Corpora-
tion (Clarence, NY) and is protec-
ted under a patent which is pend-
ing. Waste Resource Associates,
Inc. is the sole agent responsible
for the licensing of the rights to
use the leak detection system.
Disclaimer
The work in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency
and no official endorsement should be inferred.
492
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SAFE, ZERO-MIGRATION ULTIMATE DISPOSAL OF
SOLID HAZARDOUS WASTE IN SALT CAVERNS
.H.-J. Schneider *
'W. Bishop **
1 Introduction ' •
Waste has'until now been regarded as an unavoidable side effect of
industrial production. Every production process, be it raw mate-
rials exploitation, basic materials production, or product manu-
facturing is associated with waste production. Furthermore, the
consumption of the product itself also produces waste. Chemico-
physical treatment, incineration and/or final disposal are avail-
able for the treatment of such waste. According to the 4th Amend-
ment to the Law on Waste Disposal of the Federal Republic of
Germany /!/, priority should be placed on waste avoidance and
waste recycling, with the aim of minimizing the residues for final
disposal.
Despite increased efforts and interim successes in waste reduction
and recycling, the current state of waste management remains cha-
racterized by waste production on a massive scale. According to
research statistics from the Federal German Ministry of the Inte-
rior for the year 1983, the Federal Republic of Germany produces a
volume of 260 million t/a (Fig. 1) of waste (without agricultural
wastes) of which some 5 million tons are hazardous waste. Of these
5 million t/a some 10 % are incinerated, 25 % are exported to be
land.filied generally, 30 % are detoxified and 35 % landfilled.
*) Priv.-Doz. Dr.-Ing. Dipl.-Geol. Hans-Joachim Schneider
KAVERNEN BAU- UND BETRIEBS-GMBH
RoscherstraBe 7, D-3000 Hannover 1
**) W. Bishop, Vice President, Engineering
PB-KBB Inc.
P.O.Box 19672, Houston/Texas 77024, U.S.A.
493
-------
To tackle this problem, the law mentioned previously, prescribed
technical and organizational regulations designed to ensure maxi-
mized environmental waste treatment and disposal.
For waste disposal, this entails continual improvement of concepts
and methods with the aim of avoiding the errors of the past which
led to the creation of the current abandoned site problem.
SEWAGE
SLUDGE
50 m.tons
COMMUNAL
WASTE
HAZARDOUS WASTE
5 m.tons
GENERAL
HAZARDOUS WASTE 98.5 7.
RADIOACTIVE WASTE 1.5 7.
WITHOUT AGRICULTURAL WASTE 260 m.tons ALLTOGETHER
Fig. 1
Annual waste production in the Federal
Republic of Germany (source: Federal
Ministry of the Interior, 1983)
494
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2 Ultimate disposal of hazardous waste
With reference to the current state of engineering the ultimate
disposal of waste should ensure complete isolation of the dan-
gdrous materials. The environmental hazardous waste treatment is
quite insufficiently developed in many industrial countries, ac-
cording to THOMANETZ /2/. The following items are regarded as the
major critical aspects:
landfill disposal of all types of"hazardous waste without
prior systematic waste selection
the treatment of highly water soluble waste or waste particles
in water suspension in the sewage system
off-shore dumping of all types of hazardous waste
- exporting hazardous waste.
To reduce the problems associated with landfill disposal, largely
involving seepage water, long-term safety and follow-up costs,
DRESCHER /3/ proposes the strict separation of waste flows.
Accordingly, only detoxified, fixable and/or degradable waste may
be landfilled, whereas all toxic, non-conditionable and water
soluble wastes are to be finally deposited in underground reposi-
tories (Fig. 2).
In contrast with landfill concepts, underground repositories in
deep salt formations are based on natural geological barriers
which, due to their impermeability and distance to aquifers,
ensure effective isolation from the biosphere (Fig. 3).
Highly toxic, non-pyrolysable waste is currently deposited in the
Herfa Neurode salt mine repository /4/. The large amounts of
hazardous waste to be deposited in future as a result of clean air
regulations call for a more economical underground repository
concept with, higher capacities for bulk wastes. Plans are now
being developed to meet those requirements by disposal in salt
caverns.
495
-------
WASTE
COMBUSTIBLE
1NO
YES
[INCINERATION. PYROLYSIS |
I
I
RESIDUE
| YES
^ YES
IFICATION
|
1
PASTE-UKE pi!-|
| YES
riONABLE L2i
1 *ES
HONING
I
1
1 SOLUBLE P^
i NO
FIXABLE. OEGRADABIE
f YES
5 UNDERGROUND
j REPOSITORY
LANDFILL
Fig. 2
Waste treatment flow chart for hazardous waste
(according to DRESCHER /3/)
U L I- L L
1 Landfill
2 Groundwater zone -
freshwater supply
3 Drinking water well
4 Overburden
5 Caprock of salt dome
6 Rock salt
7 Salt caverns
Fig. 3
Position of surface waste disposal and salt
cavern repository in relation to the ecosystem
496
-------
3 Barrier concepts
The underlying principle of hazardous waste containment is the
shielding of the environment against toxic materials by use of
artificial or natural barriers. Because of the geochemical com-
plexity of hazardous wastes (HERRMANN, et al /5/), this may not be
simply understood as the effective sealing of the repository to
prevent toxic material migration into the environment. The in-
fluence of the atmosphere and geosphere upon the deposited wastes
as well as the interactive chemical reactions between the chemi-
cals themselves must be taken into account (GOTTNER /6/). Re-
actions in landfills are supported by groundwater (mobile phase)
which will bring different types of waste together by acting as a
solvent. This could lead to the formation of new toxic materials
against which the barriers were not designed and consequently to
the uncontrolled release of toxic materials. Typical reactions are
formations of soluble complexes with toxic anions and heavy me-
tals, resulting in mobilization of both. Some organic compounds
may permeate through hydrocarbon-based foil seals.
These criteria placed on the barrier concept require the conse-
quent realization that one should not depend on a single barrier
in order to shield the environment effectively. A number of safety
systems or multibarriers must be integrated.
In the case of landfills such a multibarrier system is designed
around the following individual parameters (STIEF, 1986 /7/):
landfill location
- landfill base sealing system
- landfill shape and dimensioning
surface seals
usage
post treatment, controllability and repairability of the
barriers
497
-------
The individual barriers of an underground repository consist of:
- host rock
- distance to surface and aquifers
- lining and sealing system
- sealing bulkheads
- waste conditioning
- emplacement
- access system to underground cavity as well as
- control possibilities and post treatment.
Disposal concepts for the ultimate disposal of hazardous waste
which ensure the maximum long-term safety and minimum post treat-
ment measures must be selected in the interest of future genera-
tions. Underground waste disposal represents the only solution for
numerous types of waste.
Salt formations, i.e. rock salt deposits possess several charac-
teristics that qualify it as the prime candidate for a hazardous
waste storage medium. Salt is in its native state solid and prac-
tically impermeable. This is a favorable factor to retain the
waste and also to shield it from groundwater,:. thus allowing the
disposal of mixtures of waste rather than segregated ones.
4 Salt cavern repository
4.1
Construction of salt caverns
Salt caverns are constructed in salt formations by solution
mining. The construction places certain requirements on the geolo-
gical characteristics of the salt structure, such as sufficient
thickness, extension above depths of 2 000 m, and relatively pure
salt composition.
To construct caverns using the solution mining process, wells are
sunk with standardized deep drilling techniques down to the pro-
jected final cavern depth. The last cemented casing extends some
100 to 200 m into the salt formation. Three concentric strings are
498
-------
installed for the actual solution mining process (Fig. 4). Fresh-
water or seawater is pumped into the cavern zone through the inner
string. The water dissolves the salt on the walls of the cavern
and the brine is extracted through the first annulus. The outer
annulus is used for blanket material (i.e. oil) injection to
control vertical leaching in the roof zone.
The current state of the art of solution mining engineering en-
ables the construction of caverns of desired dimensions /8/.
Echometrie surveys are performed to monitor the development of the
cavern shape.
FRESHWATER
L r
SUMP
rd
Construction of salt caverns using the direct solution
mining method (schematic diagram)
499
-------
4.2
Geotechnical evaluation of safety of salt caverns
The evaluation of geotechnical criteria for the safety of a salt
cavern repository is analogous to the criteria for evaluating oil
and gas storage caverns. The stability of a cavern is determined
by its position in the salt rock and by the cavern spacing in a
cavern field. The distance between the caverns must be calculated
such that stress interactions are minimized.
Special attention must be placed on cavern convergence or volume
loss. Because of its rock mechanical .properties, salt is subject
to visco-plastic deformation at the .pressures and temperatures
encountered at these depths. A cavern repository at internal
atmospheric pressure causes salt creep into the cavern with conse-
quent volume reduction. To restrict convergence the period during
which the cavern is subject to internal atmospheric pressure must
be limited. In other words, the filling with waste must be com-
pleted within a reasonable time frame.
The problem of flooding has often been raised in the context of
final deposition in salt mines. This problem does not exist in the
case of salt cavern repositories, since salt caverns are complete-
ly packed with waste after filling. Moreover, the access well will
be completely back-filled and sealed, thereby cutting off all
escape routes to the overburden or atmosphere.
4.3
Salt cavern repository operation
Before waste is deposited the brine-filled cavern is evacuated
by use of submersible pumps. The waste is fed into the cavern via
the access well. It will be continuously delivered at an projected
annual rate of 100 000 - 200 000 m3 down an additional string hung
in the well. This string protects the outer casing against corro-
sion and abrasion and can be pulled out and/or replaced in event
of damage.
500
-------
Suitable methods for emplacement are gravity-fall or pump-driven
slurry delivery. For gravity-fall filling, the waste must be
conditioned, i.e. solidified and classified, so that on one hand
it meets the specific gravity-fall dumping characteristics and on
the other, reactions between wastes in the cavern are prevented.
In the case of pump-driven slurry dumping, additives are used for
in-situ solidification.
4.4
Post operational phase
After complete filling of the cavern with waste, the cavern must
be permanently sealed against the biosphere. For this, purpose the
open borehole above the,cavern roof and the whole length.-of the
cased well are filled with cement, clay and bitumen. The surface
site is recultivated and returned to its original use. Post treat-
ment and long-term monitoring1 of the cavern repository are not
necessary, since the waste is virtually permanently (i.e., for
geological periods), isolated from the environment through the
geological barrier and the well plug. The complete back-filling of
the cavern precludes any problems relating to stability and con-
vergence.
5 Summary
Salt cavern repositories represent a significant addition not only
to landfills but also to mined underground repositories. Highly
water soluble hazardous waste, which commonly contaminates seepage
waters of landfills, can be deposited in salt caverns under zero-
migration conditions. • • . .
The operation of salt cavern repositories without -underground
staff and the high disposal capacity render salt cavern reposito-
ries economically and environmentally suitable for the disposal of
bulk waste. Although, highly toxic waste with recycling potential
should continue to be deposited in mined repositories.
501
-------
REFERENCES:
/!/ Gesetz tiber die Vermeidung und Entsorgung von Sonderabfallen
(Abfg). Bundesgesetzblatt, Jahrg. 1986, Teil 1.
/2/ Thomanetz, E. (1986): Ansatze zur umweltgerechten Sonder-
abfallentsorgung, dargestellt an ausgewahlten Beispielen.
Mttll und Abfall, Heft 8, S. 312 - 316.
/3/ Drescher, J. (1985): Ingenieurgeologische Aspekte bei der
Bonderabfallablagerung. Ber. 5. Nat. Tag. Ing.-Geol.,
Kiel 1985, S. 57 - 67
/A/ UTD: Untertagedeponie Herf a-Neurode. Firmenbroschtire,
Kali und Salz AG, Kassel, S. 16
/5/ Herrmann, A.G.; Brumsack, H.J. & Heinrichs, H. (1985):
Notwendigkeit, Mbglichkeiten und Grenzen der Untergrund-
deponie anthropogener Schadstoffe. - Naturwissenschaften
72, S. 408 - 418.
/6/ Gbttner, I.J. (1985): Mogliche Reaktionen in einer Sonder-
abfalldeponie - Folgerungen fur das Deponierungskonzept.
Mull und Abfall, Heft 2, S. 29 - 32.
/7/ Stief, K. (1986): Das Multibarrierenkonzept als Grundlage
von Planung, Bau, Betrieb und Nachsorge von Deponien.
Mttll und Abfall, Heft 1, S. 1.5 - 20.
/8/ Quast, P. und Beckel, S.: Derzeitiger Stand der soltech-
nischen Planung von Speicherkavernen im Salz und die
damit erzielten praktischen Ergebnisse. Erdol-Erdgas-
Zeitschrift (1981), H. 6, Jg. 97, S. 213 - 217
DISCLAIMER
The work described in this paper was not funded by the U.S.
Environmental Protection Agency. The contents do not necessarily
reflect the views of the Agency and no official endorsement should
be inferred.
502
-------
IN SITU TREATMENT PROCESS FOR REMOVAL OF VOLATILE
HYDROCARBONS FROM SOILS; RESULTS OF PROTOTYPE TEST
Phillip N. La Mori
Vice President and Technical Director
Michael Ridosh
Vice President
TOXIC TREATMENTS (USA) INC.
901 Mariner's Island Blvd.
Suite 315
San Mateo, CA 94404
ABSTRACT
This paper reviews the capabilities of a new in situ
remediation technique for soils contaminated by volatile
hydrocarbons and presents the results of the prototype test.
The technique uses two overlapping drills 5 feet in diameter
to dispense heat in the form of steam and hot air into the
soil to depths of 30 feet to volatilize hydrocarbons. The
drills thoroughly mix and pulverize the soil. The escaping
hydrocarbon gas vapors are contained and captured in a
surface shroud and then condensed and removed from the air in
an above ground closed-loop system. The cleaned air is
compressed and returned to the drills. We have treated 4,700
cubic yards of soil in a prototype test, reducing petroleum
hydrocarbon from 39,000 ppm to below 100 ppm in the best
case. The average reduction was 91.4% to 191 ppm. A
redesigned system is currently remediating a chlorinated
hydrocarbon site (concentrations to 8900 ppm) and the results
of this work will be given at the meeting.
503
-------
INTRODUCTION
The objective of this paper
is to review the capabilities
of a new in situ remediation
technique for soils contamina-
ted by volatile hydrocarbons
and present the results of a
site remediation.
Treatment of wastes and
contaminated soils can be
accomplished via off-site or
on-site treatment of the
excavated materials or by in
situ treatment. In situ
treatment offers the following
advantages:
o Eliminates the public health,
safety and environmental
risks which are associated
with excavation, transporta-
tion, storage and handling of
hazardous materials.
o Does not require additional
land areas for treatment.
o Soil is left in place prior
to, during and after treat-
ment.
o The process is more accept-
able to the community due to
low noise, traffic, visual
impact and emissions.
o Liability for off-site han-
dling or disposal areas is
eliminated.
There are major limita-
tions and concerns associated
with remediation approaches
which rely on the use of
liners, caps, slurry walls,
grout curtains, etc., for waste
containment and those which
involve waste excavation and
redisposal. Some of these
concerns are:
o Uncertainty regarding the
long-term effectiveness of
the available containment
technologies.
o Exposure of workers, the gen-
eral -public and the environ-
ment to additional risks
associated with site excava-
tion, transportation, and
redisposal.
o Growing scarcity of approved
off-site facilities for waste
redisposal.
o The high cost of and the in-
creasing public opposition to
schemes involving waste relo-
cation.
o Increasing criticism of on-
site waste isolation and/or
waste relocation at off-site
facilities as shortsighted
strategies that merely trans-
fer the problem to future
generations or to new loca-
tions.
The technology described
here has been used for in situ
soil decontamination using
steam and hot air stripping and
chemical oxidization of vola-
tile hydrocarbons. It has the
potential to treat soils con-
taminated by heavy rnetals, acid
wastes, drilling fluids, coal
gasification plant wastes and
to act as an in situ dispenser
of bioactive materials. We are
actively investigating the use
of the Detoxifier for these and
other applications.
PURPOSE
The purpose of this paper
is to describe a new in situ
technique for soils remediation-
and present the results of the
prototype test. This test was
a full scale commercial remedi-
ation project on a site that
504
-------
was being redeveloped as a
commercial office complex. The
remediation was successful and
permission to continue the
development was subsequently
granted. The results of a
second project, currently in
progress, will also be
presented.
APPROACH
The heart of the Detoxifier
technology is the "process
tower" which is essentially a
drilling and treatment agent
dispensing system, capable of
penetrating the soil/ waste
medium to depths of 30 feet or
more. The process tower
consists of an assembly of two
cutter/mixer bits connected to
separate, hollow kellies. The
bits overlap and rotate in
opposite directions. The
rotating action provides for
simultaneous cutting, mixing,
homogenizing and pulverizing of
the soil. Treatment agents in
dry, liquid, gaseous or slurry
form can be conveyed through
the hollow kellies and ejected
through spray nozzles into the
soil where they are mixed and
homogenized (see enclosed
figure).
The treatment of a site is
on a block-by-block basis. The
site to be treated is divided
into rows of blocks, with the
process tower being moved to an
adjacent block after treatment
of the previous block is
completed.
The bit assembly is two
overlapping cutting blades 5
feet in diameter. To cover all
of the area to be treated, the
drill is positioned with about
10 percent overlap of the grid
blocks. With this overlap, the
effective treatment volume, or
a treatment block, is about 30
square feet of surface area
times the number of feet of
depth to be treated. Each foot
of depth is equivalent to a
little more than one cubic
yard.
A rectangular enclosure
called a shroud covers the
treatment area to eliminate
dust and to capture gas and
vapor released during the sub-
surface treatment process. The
captured offgas is treated in a
process train and recycled
through a compressor back to
the process tower, then down to
the treatment zone.
This closed-loop operation
of the Detoxifier eliminates
the release of volatile contam-
inants into the atmosphere.
The unit processes comprising
the treatment train are selec-
ted and designed based on • the
type and level of pollutants
that are to be removed from the
offgases.
In the treatment train used
for hydrocarbon stripping, the
of fgas from the shroud which
contains the exit air, steam
and volatilized hydrocarbons,
is condensed in a three-stage
cooling system. Each cooling
stage is followed by a cyclone
demister. The final stage
lowers the temperature ofF the
gases to -10 deg. F. The gas
stream is then passed through a
bed of granulated activated
carbon (GAC) for removal of any
remaining hydrocarbons.
Following carbon absorp-
tion, the purified gas is
compressed, reheated and recy-
cled to the treatment zone
through the two kellies in the
process tower.
505
-------
The hydrocarbon content of
the shroud offgas is monitored
continuously by a total hydro-
carbon analyzer with a flame
ionization detector (FID). The
FID reading is used to adjust
the treatment conditions, in-
cluding the duration of treat-
ment, to achieve desired treat-
ment objectives.
The important features of
the Detoxifier system, which
represent significant innova-
tions and advances for in situ
treatment, are the following:
o Delivery of the treatment
agents directly to the treat-
ment zone.
o Thorough mixing and homogeni-
zation resulting in effective
contact between the treatment
agents and the contaminant.
o Closed-loop operation.
o Ability to use a range of
treatment agents in liquid,
gas, solid and slurry forms,
thus providing versatility
and ability to implement a
range of options. These
include thermal treatment,
stripping of volatile organ-
ics, oxidation, reduction,
precipitation, neutralization
of inorganics and stabiliza-
tion, solidification, fixa-
tion or biodegradation of a
wide variety of contaminants.
o The treatment system is
mobile and transportable.
PROCESS DESCRIPTION
A prototype in situ
Detoxifier was utilized in the
summer of 1986 for remediation
of a site in Los Angeles,
California, under development
as a light industrial and
office complex. The site had
previously been used as a truck
terminal. During initial
construction on the site, five
underground tanks were uncov-
ered. The tanks had contained
gasoline and diesel fuel.
Leakage from these tanks had
contaminated over 4,700 cubic
yards of soil. The in situ
Detoxifier was selected for
remediation of the site after
an evaluation of alternatives
because it: 1) did not require
transport of hazardous mater-
ials 2) solved the waste prob-
lem as opposed to merely
displacing it and 3) was an
immediate solution requiring
only a few months to complete.
The remediation process was
initially investigated in a
bench scale test using soil
samples from the site. Those
studies demonstrated that
potassium permanganate, oxida-
tion as well as steam and hot
air are effective for the re-
moval of hydrocarbon contamina-
tion. Hence the cleanup
operations at the site employed
steam and hot air stripping and
varying amounts of oxidation
via potassium permanganate in
the highly contaminated zones.
OPERATIONAL VARIABLES
The only variables associ-
ated with treatment by the
Detoxifier are:
1. The speed of rotation.
2. The rate of penetration of
the soil.
3. The amount of time spent on
any one treatment block.
4. The number of passes of the
drill blades through a con-
taminated zone.
506
-------
The energy supplied by the
steam and hot air for stripping
the volatile compounds are
delivered to the soil at the
maximum output rate of the
boiler and compressor. These
values are presented in Table
I.
RESULTS
The Detoxifier was effec-
tive in reducing the level of
petroleum hydrocarbon compounds
found in the soil at a wide
range of concentrations. For
example, in the northern por-
tion of the site where initial
hydrocarbon concentrations were
on the order of 1,000 ppm or
less, removal efficiencies of
75-90 percent were routinely
achieved with operation of the
unit on a 15' soil column for
an average of 47 minutes with-
out potassium permanganate
addition. In the southern
portion of the site where
initial hydrocarbon concen-
trations averaged 10,000 ppm
but reached 39,000 ppm, removal
efficiencies of 90-95 percent
were routinely achieved with
operation of the unit on a 22'
soil column for an average of.
78 minutes. The Detoxifier
system was demonstrated to be a
viable alternative to the
current technology used in
contaminated soil remediation.
Some limitations in the ability
to remove the higher molecular
weight, less volatile compon-
ents of the diesel fuel were
encountered. Table II below
summarizes the treatment
achieved.
PROBLEMS ENCOUNTERED
The main problem encoun-
tered was related to the
prototype design of the process
train and the anticipated
concentration of the soil
hydrocarbons. Analysis of the
soil chemical samples before
the project showed a maximum of
4-5000 ppm hydrocarbons. The
process train was designed for
TABLE I - OPERATIONAL PARAMETERS
j Volume Temperature j Pressure
Air j 600 cu. ft./min. 400 deg. F j 250 psi
i i
i i
Steam J3,100 Ib./hr. 400 deg. F j 400 psi
TABLE II
TOTAL PETROLEUM HYDROCARBONS (PPM) METHOD 418.1
Initial Final
Mean 2222.5 191.4
S.D. 6059.0 301.8
Maximum 35,980 2170
%Reduction = 91.4%
507
-------
this level. In one area of the
site, the actual concentration
proved to be much higher, up to
39,000 ppm. This caused prob-
lems with the operation,
resulting in overloading of the
carbon filters and recycling of
hydrocarbons into the soil.
When this occurred, the soil
cleanup criteria were difficult
to meet. However, when the
system was operating within
design parameters, the soil
cleanup levels were readily
achieved. The process train
has been redesigned to handle
over 100,000 ppm initial
hydrocarbon concentration in
the soil. The operating
procedures can be adjusted to
alleviate overloading of the
process train so that the
current unit can remediate any
type or concentration of hydro-
carbon contaminated in soil.
The results of the proto-
type test were used to signifi-
cantly modify the Detoxifier
process train and process
tower. The major problem found
with the prototype consisted of
ineffective condensation of the
volatile petroleum hydrocarbons
which resulted in overloading
the granulated activated carbon
(GAG) filter. This resulted in
recycling of hydrocarbon gases
and frequent changes of the
GAG, decreasing treatment
efficiencies. A modified
Detoxifier has been built and
is being used for remediation
of a volatile chlorinated
hydrocarbon site. Results from
this project will be presented
at the meeting.
DISCLAIMER
The work described in this
paper was not funded by the
U.S. Environmental Protection
Agency. The contents do not
necessarily reflect the views
of the Agency and no official
endorsement should be inferred.
"508
-------
-------
-------
THE ONE-STEP METHOD FOR RECOVERY AND REUSE
OF WASTE CHROMIUM FROM ELECTROPLATING PLANTS
BY
YANCEY CHOU
SHANGHt, THE PEOPLE'S REPUBLIC OF CHINA
ABSTRACT
This industrial pollution control method is applicable to the recovery of chromium chemicals
from electroplating waste effluents and sludges from treating electroplating wastewaters.
Through this method, the materials can be recovered and reused to make all sorts of chromium
products. The use of process requires only that two different chelating agents, which are actually
byproducts from a chemical manufacturing plant, be poured together simultaneously. The
procedure can be accomplished with very simple equipment, which is easily installed. The results
are environmental protection for the public, plus complete recovery of the chromium for reuse.
INTRODUCTION
Environmental concerns are in a dynamic
state ail over the world. During the past twenty
years, we have seen a change in philosophy
from near total neglect of the effects of
industrial pollution to the realization, by
responsible people of its serious effects. (1) The
most recent philosophy, in response to the
economic problems experienced worldwide, is
that "pollution control is good business." In
some developing countries and emerging
industrial nations, pollution control is a high
priority rather than just a minor concern. This
was clearly expressed by Dr. Mostafa K. Tolba,
Executive Director of the U.N. Environment
Program at the World Industry Conference on
Environmental Management. (2)
The environmental pollution problems in
China, especially in Shanghai, are still in some
degree of disorder. Pollutants are still being
dispersed with carelessness. Recently, however,
the governments of Shanghai and the People's
Republic of China are beginning to handle toxic
substance control programs as one of the city's
main priorities. Previous regulations only limit
the effluent contents as a percent of volume,
but not in accordance with the quantity of
pollutants.
In the past 35 years since the liberation of
China, the major attention to industry was on
production, and only secondarily was emphasis
placed upon pollution control. Shanghai is an
old-style city: All the sewer lines are outmoded
and currently not available to all sites.
Moreover, the old-style city construction has still
not been altered and upgraded. Some factories
dilute the effluent prior to pipeline discharge.
Factories located at the side of the river might
even discharge directly into the river. Most of
the managers and directors of the factories are
only concerned with production and do not care
about pollution control. They would rather pay
the fines involved since they consider them to
be minimal and furthermore such fines are not
paid out of their own pockets.
A wise man, who is deeply interested in
protecting Shanghai's environment, suggested
dispatching the electroplating plants and
disbursing them throughout the countryside to
avoid polluting the city. But he did not know
that the government could best control the
industry only when the polluters are
concentrated and not when they are dispersed.
According to the geographical and hydrological
situation in China, most of the rivers flow
eastward, as illustrated in Figure 1. The Yantse
511
-------
River, which passes through Shanghai, flows
into the sea. Therefore, all pollutants from the
countryside would be passed through Shanghai
(see Figure 2).
The People's Republic of China now
intends to improve environmental protection.
However, most of the Chinese cadres have not
yet gained acceptance of this new policy. There
is a serious shortage of practical knowledge and
experienced people in China concerning
wastewater treatment technology and
management.
The alternative idea to disbursing the
electroplating plants is that of using large
volumes of water to dilute the effluents to a
point where they are acceptable in the
discharge. This method can be employed only
where water is available and the receiving river
can tolerate the discharge. In an increasing
number of cases, this method is not applicable.
Even where it is, some treatment procedures are
usually necessary, such as reduction of
chromates and pH adjustment. If dilution is to
be applied to meet discharge limits, it is better
to do so" after treatment of the more
concentrated or more toxic rinse waters.
PROBLEM IDENTIFICATION
Most metal finishing operations involve
two main processes. The first consists of
treating the workpiece in a solution or chemical
process tank, and the second consists of
removing excess chemicals, that is rinse, from
the workpiece (i.e., the rinse process). This
excess chemical is called "drag out." Typical
electroplating plant processing operations for
chromium are shown in Figure 3.
Chromium is extremely toxic in its hexavalent
form. Hexavalent chromium in plating rinse
waters must be reduced to the trivalent form,
which is much less toxic (see Figures, Typical
Chromium Plating Line).
CONVENTIONAL METHODS FOR TREATMENT OF
CHROMIUM WASTES
The treatment of rinse waters from
chromium plating operations usually consists of
one or a combination of the following
procedures:
1. Reduction of hexavalent chromium to the
trivalent form followed by the
precipitation of the reduced chromium as
the hydroxide.
2. Reclamation of chromic acid from the
more concentrated rinse stream by
evaporation or ion exchange techniques.
3. Removal of hexavalent chromium by the
addition of compounds that form
insoluble salts (e.g., barium chromate).
Reduction of Hexavalent Chromium and
Precipitation of Chromic Hydroxide
Methods for reduction of hexavalent
chromium vary with each particular plant.
Common reducing agents are gaseous sulfur
dioxide; sodium bisulfite, metabisulfite, or
hydrosulfite; and ferrous sulfate.
Reduction with sulfur dioxide (SO2) is the
method most commonly employed by many
large plating plants. Basic equipment for this
method consists of sulfonators for combining
sulfur dioxide with water and agitated tanks for
conducting the reduction. During reduction
sulfuric acid is normally added to maintain an
acid solution with a pH range of 2.0 to 3.0.
Under these conditions, the following reactions
occur:
S02
(Sulfur
dioxide)
2CrO3 •
(Chromic
acid)
H2O
(Water)
3H2SO3
(Sulfurous
acid)
-» H2SO3
(Sulfurous
acid)
Cr2(S04)3 + 3H2O
(Chromic
sulfate)
512
-------
The approximate chemical usage is
1 gram of SOa per gram of chromic acid (CrOs) in
the waste solution.
PURPOSE
After a series of laboratory experiments, I
have begun a pilot-scale batch trial. It is
expected that the following will be achieved:
• Elimination of chromium VI and
chromium III in the effluent.
• Elimination of the toxic off gases from
the reaction vessels.
• Elimination of trace concentrates of
chromium VI and III from the sediments
and sludges.
Utilization of
technology.
Simplification
equipment.
a simple and easy
of installation and
• Recovery and reuse of the chromium and
rinse water.
APPROACH
Currently, the prevailing treatment in
China for most of the electroplating plants
involves adding ferrous sulfate and sodium
hydroxide to waste chromium liquor. This forms
precipitates of chromium hydroxide. These are
collected as dried sediments, stored in ragged
bales, and left on the ground out in the open
air. To my knowledge, this procedure is
conducted everywhere in China.
Another available process is to use an ion
exchange method, but this has two
Shortcomings: First, the resulting chloride ion
causes harm when the wastewater is reused,
and second, the price of ion exchange resin
often is too high. The method that I selected
and report here uses sodium ferrocyanide (NFC)
together with a tertiary amine, which serve
respectively as chelating and emulsing agents.
However, this method is comparatively
expensive.
As an alternative method, I used the black liquor
from the wastewater diethylamine
manufacturing plant. Excellent experimental
results were achieved from both laboratory test
and batch-scale operations, which gave similar
results. I found that there was 0.7mg/l
chromium remaining in effluent when I used
NFC alone. In the following step, I added the
black liquor containing the diethylamine. The
results indicated there was no trace of
chromium within the effluent or the resulting
sediments. The amines have the capacity for
reacting with hexavalent chromium in acidic
solutions by the following mechanism.
2R3N
Cr2O7= +2H+ -» (R3NH)2 Cr2O7
(amine) (dichromate ion (compound of
in acidic amine with
chrome rinse dichromate with
waters) negligible solubility
in water)
The following table expresses the results
achieved by the reaction of chelating agents on
NFC using various metal ions other than
chromium.
Metal
Ions
Na +
K +
Fe* +
Fe+ + +
Uo-1"1-
Mn-*-
Co
Cu
Zn
Precipitate
Color
IM/A
N/A
Blue
Dark Blue
Brown
Light Green
Bluish Green
Red
White
Adsorption/
Dissociation
Solute
-Sl
si
513
-------
Metal
Ions
Pb
Sn
Sr
Al
Cd
Au
Ag
Ca
Ba
U
Th
Cs
Mg
Mo
V
Tl
Ga
Precipitate
Color
Yellowish White
White
White
Brown
White
Adsorption/
Dissociation
Disso.
Adsorb
Adsorb
Adsorb
Solute
si
si
s
s
s
s
si
s
Character
Cyanide (CN) is tightly bonded with iron
in ferrocyanide form and therefore is not easily
decomposed. This reaction takes place at room
temperature and in a diluted acidic solution.
Finally, the sodium ferrocyanide can be recycled
and reutilized, but tertiaryamine is
decomposed. This process is quite safe and
inexpensive. NFC can be chelated in the
presence of many metal ions. It appears that
neither a precipitation nor turbide solution
form during the reaction. Meanwhile, NFC
chelated with nickel is green in color. Chelated
with copper it is red; with zinc, white; and with
lead, a light yellowish white. When it is
chelated with chromium, no color develops.
The following shows the affinity of metal ions
with Oxygen (O) and Nitrogen (N). (The relation
is arranged in series.)
O > N Mg, Ca, Sr, Ba, In, Tl, Ti, Zr, Th, Si, Ga, Sn, V+5
V+", Cb, Te, Mo, U + 6, (j+4, Fe+3, co+2
N > O Cu + , Ag + , Au, Cu+2, Cd, Hg, V+3, Co + 3, Mi*2
All above relations of affinity never
mention chromium. It was learned that the
radius of the chromium ion is 0.3A.
Chemical Reaction
and Na4Fe(CN6) no evidence
Cr2(SO4)3 and R4Nx Cr(NHR3)H2O
where n = 1-5
R = C - C8
When the effluent contained Nickel (Ni),
Copper (Cu), and Iron (Fe), it reacted with
ferrocyanide, producing various colored
precipitates shown in the table above.
THE RESULTS
By means of the described co-treated
method of NFC and black liquor wastewater,
the final test of the effluent and sludges
resulted in satisfactory concentrations.
Test No.
1
2
6
7
8
Cr(mg/l)
6*
0.05
0.01
0.07
nil
nil
3 +
0.45
0.09
nil
nil
Tests 1 and 2 use NFC alone.
Test 6 is the test of effluent in the batch trial.
Tests 7 and 8 are the sludge analysis when
NFC is used with black liquor.
514
-------
The results of the laboratory and field
batch trials confirm that NFC and wastewater
black liquor from a diethylamine manufacturing
plant can be used to effectively and
inexpensively treat toxic chromium from metal
finishing plants.
ACKNOWLEDGMENTS
The analytical laboratory support service
was received from the Sanitation and Epidemic
Prevention Station of QIN-AN District of
Shanghai. The reuse of the chromium sludge
was sponsored by Mr. ZeeYi-din. He is the
Assistant Engineer in the Dah-fong Chemical
Factory of Shanghai, Peoples Republic of China.
REFERENCES
1. George Rey, William J. Lacy, and
Allen Cywin, "Industrial Water Reuse:
Future Pollution Solution," Environ-
mental Science and Technology, Vol.5,
No. 9 (1971).
2.
3.
4.
5.
6.
7.
8.
Mostafa, K. Tolba, "World Industry
Conference on Environmental
Management," United Nations
Environmental Programme, Versailles,
France, November (1984).
F. P. Dwyer and D. P. Mellor, "Chelating
Agents and Metal Chelates."
E. Arthur Martell and Melvin Calvin,
"Chemistry of the Metal Chelate
Compound."
An Ahorg. Align. Chemia (321) 175-9.
Ibid.. 180-3(1963).
International Solvent
Conference (1980).
Extraction
University Rajptana Studies Physical
Science (1962) 45-55.
515
-------
Disclaimer
The work described in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency, and no official
endorsement should be inferred.
516
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REUSE OF WASTE FERROUS SULPHATE
Lucjan PAWLOWSKI nad Marek KOTOWSKI
Department of Waster and Wastewater Technology
Technical University of Lublin
40, Nadbystrzycka Str., 20-618 Lublin,POLAND
ABSTRACT
Processes of manufacturing of the yellow, red and black iron pigments
from a waste ferrous sulphate are discussed in this paper.
INTRODUCTION
Large quantity of waste ferrous
sulphate generated during either
production of titanium white (tittia-
nium dioxide) or metal pickling
operations creates an environmental
problem with its storage. Stored in
dumps, it penetrates to ground waters.
In Poland, there are a few million
tons of waste ferrous sulphate stored
in dumps. Ferrous sulphate may be a
product for:
- agriculture for production of
herbicide and insecticide,
- wood preservation,
- dyeing and tanning industry,
- production of photographical
developers,
- ink production,
- production of sorbents to
desulphurization of natural and
converter gases,
- waters and wastewaters treatment
(as reductor and coagulant).
All the above applications do
not utilize the huge quantities of
waste ferrous sulphate and therefore
the studies on new applications is
of significant practical importance.
Production of iron pigments from
waste ferrous sulphate seems to be a
proper way of its utilization. The
demand for these pigments in Poland
is about 40000 tons per year and it
is almost all imported. According to
literature, the greatest application .
and demand have been obserbed for yellow
(06- FeOOH), red (<£ -Fe203) and black
iron pigments (Fe304- magnetite). Among
the iron pigments, the yellow one is
commercially most important because
it is widely used for production of
dyes, magnetic supports and for
manufacturing red and black pigments.
AIM OF STUDY
Th3 aim of the study is to work out
a simple method of manufacturing the
yellow iron oxide pigment from waste
ferrous sulphate generated as a waste
product during production of titanium
white.
The manufacturing of yellow iron
oxide pigment may be carried out by:
- oxidation of solution of Fe(II)
-------
2H20
+
salts in the presence of metalic
iron in acidic environment
|Matsuo Y.;1954; Oda M.;1960a|;
- oxidation of suspension of Fe(OH)2.
Such oxidising agents as chlora-
tes (Edwards W.H.;1962|, hypochlorites
Krause A.;1955a|, nitrobenzene
Riskin J.;1946|, H202 JKrause A.;
1955a; Krause A.:1963b|, oxygen
Voigt C.W.;1948| and air
Kasherininov G.0.;1968| are most
frequently used. For neutralization
one of the following agents: NaOH
|Oda K.;1969b; Northern Pigment Co.
Ltd 1964 , Na2C03 |Riskin J.;1946|,
Fe(OH)2 Minot M.A.;1949|, gaseous
NHj or its aqueous solution
|Naganuma U.;1963a; Naganuma U.;
1968b|, may be used.
The oxidation reactions can be
depicted by eqs.:
4Fe+2 + 02 + 80H~ - 4FeOOH + 2H20
4Fe(OH)2 + 02 - 4FeOOH
4Fe+2 + 02 + 4H20 - 4FeOOH + 4H
When NaOH is used for neutraliza-
tion, waste solution left after
separation of <%- FeOOH contains
Na2S04 and NaOH, what makes such
wastewater treatment more compli-
cated. In the case when NH3 is
used for neutralization, the waste
solution contains only (NH4)2S04.
Utlilization of such wastewater
is easier.
Therefore, we have decided to
study only these processes where NH3
is used for neutralization, using
two procedures:
- precipitation of Fe(II) in the
form of Fe(OH)2 with
stoichiometric amount of NH3 and
aeration of slurry with air for
oxidation of Fe(II) to Fe(III);
- fractional precipitation of
Fe(II) in the form of Fe(OH)2
with NH3 and aeration of each
fraction (together with whole
solution) with air for
oxidation Fe(II) to Fe(III).
There were two series of experi-
ments. First one, when solution of
FeSO, was prepared by dissolution of
a ferrous sulphate in pure water and
the second one, when the ferrous
sulphate was dissolved in solution
of (NHJzSO,,.
RESULTS
As Figs 1 and 2 show, it is
imposible to obtain iron oxides pigments
when, before aeration, the total amount
of Fe(II) is precipitated in one step
with a stoichiometric amount of ammonia.
Depending on a concenzration of the
ferrous sulphate in a solution (see
Fig.l) and intensity of aeration (see
Fig.2), the following products of
oxidation of Fe(II) to Fe(III) were
obtained. That is:
- pure Fe(OH)3 or one of the follow-
ing mixtures;
- i - FeOOH + Fe(OH)3 + Fe304 br
- y - FeOOH + Fe304.
Iron oxides having pigment
properties were formed when a fractio-
nal precipitation and aeration of
each precipitated fraction was applied.
At lower intensity of aeration i.e. 10
to 15 mVhm3 the yellow pigment
(cv, -FeOOH) was formed, while at
intensity of aeration 50 m3/hm3 the
orange pigment (if -FeOOH) was formed,
and at intensity of aeration between
these values amixture of ^ - FeOOH
and / -FeOOH was obtained, which have
colour changing from yellow via yellow-
-orange to orange.
Mechanisms of the oxidation reac-
tion Fe(II) to Fe(III) were not
thououghly studied, however some
qualitative obserwations were made.
It was found, that there are three
stages of the oxidation reactions
(see Fig.3):
- the 1st etage, where the reactions
produce an excess of hydrogen ions
522
-------
&
u_
•o
'x
o
01
A-0.018 M FeS04
o-0,18 M FeS04
x-0,25 M FeS04
e-0,50 M FeS04
0-0,60 M
3 A
Reaction time [ h]
Fig. 1. Procentage of oxidation Fe(II) to Fe(III) as a function of reaction
time for various concentrations of the ferrous sulphate. Intensity of
aeration 120 m3 of air/hm3 of solution. Final products: A.- Fe(OH)3;
0 - Fe30A + y - FeOOH + Fe(OH)3; x - Fe3u\ + /- FeOOH;
• - Fe30^ + x -• FeOOH; O - Fe30, + y - FeOOH; - Fe(OH)3 +
+ - FeDOH. 4
and therefore ph drops from 8 to
6;
- the 2 nd stage where pH is stable
around value of 6. In this stage
so called "rust green II"
|4Fe(OH)2. 2Fe(OH)3. FeSO^ nH20]
is formed;
- the 3rd stage, where again the
reactions produce an excess of
hydrogen ions and therefore pH
drops from 6 to 3.
The stages are observed during aera-
tion of each of four fractions.
A flowsheet of the process
based on fractional precipitation
and oxidation is depicted in Fig.4.
In a reactor, a solution of the
ferrous sulphate was mixed with 25%
of stoichiometric amount of ammonia,
then aerated till the sludge in the
reactor reached yellow colour. Then
the next portion of 25% ammonia was
added and a mixture was aerated
untill the sludge reached again
yellow colour. This operation was
repeated four times.
In the next operation a sludge
was separated from a solution of the
ammonium sulphate. The sludge was
rinsed with water circulating via a
strongly basic anion exchanger which
was regenerated with a 4% solution
of the sodium hydroxide. A regenera-
tion effluent containing the sodium
sulphate is discharged as a waste-
water.
523
-------
1
c
o
*a
•o
'x
o
o
-------
A-10m3 of air/h-m^ of solution
«-15m3 of air/h-m^ of solution
x-30 m^ of air/h m^ of solution
o-50m^ of air/h m^ of solution
Reaction time [ h]
Fig. 3. Influence of reaction time on pH of the aerated solution of the 0.5M
ferrous sulphate. Before aeration 25% of Fe(II) was precipitated in a
form of Fe(OH)2 with ammonia. Final products: A - ot - FeOOH; ® - <* -
- FeOOH; x - ex; - FeOOH + y - FeOOH; o - tf - FeOOH.
which decreases with an increase of
a concentration of the ammonium
sulphate in a solution of the ferrous
sulphate to be oxidized (see Fig. 5
and 6).
The ferrous sulphate may be used
also for manufacturing of red and
black pigments (see Fig. 7). The red
pigment was obtained by calsination
of the yellow pigment. To obtain the
black pigment (see right side of Fig.
7) it was necessary to heat a solu-
tion containing a mixture of the
ferrous sulphate and hydrogen
piroxide (H202) to temperature 80-
-95 C, and then to add a stoichiometric
amount of ammonia during stirring. The
black pigment obtained was then
separated, rinsed and dryed on spray-
-dryer.
A solution of the ammonium sulphate
leaving a filtration unit was
directed to an ammonia stripping unit.
The ammonia recovered, in the stripper
was used for fractional precipita-
tion of the ferrous hydroxide.
The processes depicted in Figs.
4 and 7 allow to "convert" an
usless waste ferrous sulphate into
the,useful iron oxide pigments.
Disadvantage of these processes is
that although the waste ferrous
sulphate is elimnated, a problem of
a protection of the environment still
exists, because new wastes, solid
calcium sulphate and wastewaters
containing calcium and sodium
sulphates are generated. Fortunately,
they are less harmful. However, it
is possible to eliminate the waste
calcium sulphate and its solution by
utilization of the ammonium sulphate
as a fertilizer. Usually, the solu-
tion will need to be concentrated or
525
-------
Fractional precipitation
and oxidation
Filtration
CaO
JL
Stripping of ammonia from
solution of
Rinsing
Waste: solid
CaSO/; and
solution-2g
CaSCWdm3
[Spry dryer
NaOH for
Strongly basic
anion exchanger
Fig. 4. A flowsheet of the process for production of the yellow iron oxide
pigment from the waste ferrous sulphate.
even solidified by evaporation.
ACKNOWLEDGMENT
We gratefully acknowledge the
financial suport of the CPBP No
03.08. we also acknowledge the expert
technical assistance of Mrs. Grazyna
Miodawska, Miss Ewa Smulkowska and
Mrs. Elzbieta Zolnierczuk.
Disclaimer
The work described in this paper was
not funded by the U.S. Environmental
Protection Agency. The contents do
not necessarily reflect the views of
the Agency and no official endorse-
ment should be inferred.
526
-------
c
o
-4—
a
x
o
**—
o
a>
Ol
o
H-»
c
ai
0
i_
O_
A f\ r\
—, 1UU
£ 90
" 80
— 70
= 60
i£ 50
o 40
-*-•
— 30
= 20
CD
"• 10
/ s /* /°
/ X • /°
: / / y^
/ :/ ;*'* ^^ e>-0 M (NH4)2S04
^{s>r /* ;oX X-0.5M (NH4)2S04
S&S**' .X*^°^° »-1.0M (NH4)2S04
. & ^r^^tf^ o-1. 5M (NH4)2S04
•Srf^^^O*^^*^, | | l ' - i
0 1 2 3 ; 4 5
Reaction time [ h]
Fig. 5. Procentage of oxidation of Fe(II) to Fe(III) as a function of reaction
time for various concentration of the ammonium sulphate in a mixture
with 0.5M solution of the ferrous sulphate. Intensity of aeration 10 m3
of air/hm3 of solution.Final products:&,x,e,o, - a. - FeOOH.
PH
i
8
7
6
5
4
3
i
^^
%N> e-O M
X?xN> X~0.5M
°^^^o-o-o^o »-1,OM
*»o— ^
^ 'v»a "~ *
Xe-0^rr^x-"
i i i i
0-1 2 3 4
Reaction ti
(NH4)2S04
(NH4)2S04
(NH^)2S04
{NH4)2S04
«— •
,
5
me [ h]
Fig. 6. Influence of reaction time on pH of the aerated for various concentra-
tion of the ammonium sulphate in a mixture with 0.5M ferrous sulphate.
Before aeration 25% of Fe(II) was precipitated in a form of Fe(OH)2
using ammonia. Intensity of aeration 10 m3 of air/hm3 of solution.
Final products: 0 , x , 0 , o, - °c - FeOOH.
527
-------
ammonia stripping
NH3~from ammonia stripping
Solution
of FeSO/,
Fractional
precipitation
and
oxidation
Heating
to 80-95°C
Filtration
and heating
Strongly
basic' anion
Stripping of
ammonia from
solution of
Rinsing
of pigment
.
exchanger
'
j Spry dryer
aste:
solid CaSO/,
and solution
~2g
Yellow pigment
| Spry dryer]
[Black pigmenO
Vapour-to ammonia stripping
Fig. 7. A flowsheet of the process for production of yellow, red and black
iron oxides pigments from the waste ferrous sulphate.
528
-------
REFERENCES
1. Edwards, Webster H.; U.S. Pat.
3,052,644; 4 September 1962;
2. Kasherininov G.O,; USSR Pat.
213 996; 20 March 1968;
3. Krause A., Krang M.,
Fijalkowska J.; Chem. Abstr.
55(1961), 17333;
4. Krause A., Zielifiski S.; Chem.
Abstr. 59_(1963), 7753
5. Matsuo Y, Tanaka H.; Jap. Pat.
8018/54; 7. December 1954;
6. Minot, M.A.; Fr. Pat. 953-329;
5 December 1949;
7. Naganuma U.; Jap. Pat. 17652/
/63; 10 September 1963;
8. Naganuma U.; Jap. Pat. 11661/68;
16 May 1968;
9. Northern Pigment Co. Ltd.; Can.
Pat. 698.715; 24 November 1964;
10. Oda K.; Jap. Pat. 28,372/69;
21 November 1969;
11. Oda M.; Kagitani T.; Jap. Pat.
9027/60; 12 July 1960;
12. Riskin J., Velikoslavinskaya T.;
J.appl. Chem. (USSR), JJK1946),
262;
13. Voigt, C.W.; Chem. Abstr.; 42_
(1948) 70 62 e.
Disclaimer
The work in this paper was not funded by the U.S. Environmental Protection
Agency. The contents do not necessarily reflect the views of the Agency
and no official endorsement should be inferred.
529
-------
-------
BARIUM RECOVERY FROM SPENT HARDENING SALTS
Ryszard Szpadt and Marta Sebastian
Institute of Environment Protection Engineering
Technical University of Wroclaw
PL 50-370 Wroclaw,Poland
ABSTRACT
Spent hardening salts contain water-soluble barium chloride
and are, therefore, classified as waste substances creating se-
rious environmental hazards. Since those hazardous wastes are
produced in relatively small amounts by a number of plants wor-
king for the metal industry of Poland, they have usually been
disposed of at municipal or industrial dumping sites which are
not suitable for receiving such loads. In this paper the compo-
sition and physico-chemical properties of spent salts, water
extracts and extraction residues are characterized. Attempts
have also been made to recover barium from water extracts by
precipitation of low-solubility salts, barium sulphate and ba-
rium carbonate. Owing to a high degree of purity, recovered
salts are suitable for reuse.
Technological systems enabling barium salts recovery and
disposal of extraction residues are suggested. Keeping in mind
that the wastes of interest are produced in a number of sources
scattered throughout the country, barium salts recovery should
be carried out only on a nation-wide or at least on a macrore-
gional scale. The most recommendable concept is that involving
treatment and regeneration by the manufacturer. The waste mana-
gement concept proposed has two inherent advantages - it enab-
les barium recovery and reuse, thus abating environmental pol-
lution from this specific hazardous waste.
INTRODUCTION AND PURPOSE
The most common hardening
method to be encountered in
the machine-building industry
of Poland is the application
of salts containing barium
chloride as a main component.
Displaying a high water-solu-
bility, barium chloride can
easily penetrate the environ-
ment, and particularly ground-
531
-------
and surface waters, thus crea-
ting serious hazards to munici-
pal water supply systems. These
hazards will manifest especial-
ly when spent salts are dispo-
sed of inappropriately, e.g. by
storage on municipal or indust-
rial dumping grounds which fail
to meet the sanitary standards
required. And this is a fre-
quent practice in the metal in-
dustry of Poland. Implementing
an adequate system for the col-
lection and processing of such
wastes should help not only in
the abatement of environmental
contamination by a toxic subs-
tance, but also in the reasona-
ble recovery or reuse of barium
salts (1,2,3) .
Spent and contaminated salt
baths produce two major kinds
of wastes:
( a ) spent hardening salts,
routinely removed from the salt
furnace, and
( b) impurities ( removed re-
gularly, at least once a week,
from the furnace bottom) con-
sisting of small iron fillings,
ash, dust particulates, melted
salts and salt degradation pro-
ducts.
There is only a slight dif-
ference in the composition bet-
ween the two types of wastes -
spent hardening salts contain
less impurities than do the
wastes removed from the salt
furnace bottom. In this paper
consideration is given to the
type itemized as {b), because
these wastes are more difficult
to treat.
The objective of the study
{ 4) was to determine the compo-
sition and physico-chemical
properties of the wastes, water
extracts and extraction resi-
dues, to develop methods of ba-
rium recovery from water ex-
tracts in carbonate or sulphate
form, and to present a general
concept of waste barium salt
management in Poland.
APPROACH
The experiments were run
on a laboratory scale and in-
volved 17 samples, which had
been milled to obtain grain
size <2 mm.
Physico-chemical analyses
and technological investiga- ,
tions included the following:
- determination of Ba, Sr,
l?e,Na,K, Ca,Mg, Pb, Zn,Ni, Ou, Or,
Gd,Mh and Co content in salt
wastes by atomic absorption in
solutions after mineralization
in a mixture of concentrated
HGICL+HNO., acids, using a Oarl
Zeiss-Jena AAS1 spectrophoto-
irieter.
- thermogravimetry invol-
ving an OD-102 Paulik-Erdey
derivatograph made by MOM Bu^
dapest.
- single- and multi-stage
water extraction in order to
dissolve and wash out barium
chloride from salt wastes.
Single-stage extraction invol-
ved mixing of 50g of waste and
1 dm3(liter) of distilled wa-
ter. After 24 h the extract
was decanted. In multi-stage
extraction 50g of waste were
mixed with 1 dnP of distilled
water. The extract was decan-
ted after 4 h. The residue was
subject to five extraction
processes ( each of them invol-
ving 250 cm^ of distilled wa-
ter ) with the aim to determi-
ne barium content in successi-
ve extracts.
- determination of the
composition and properties of
water extracts by making use
of standard methods { for wa-
ter and wastewater) .
- determination of the
532
-------
chemical composition of the
residue from extraction. Ana-
lytical procedures were the
same as those for wastes.
- microscopic examinations
of salt wastes and residues
from extraction, using a Cam-
bridge-Stereo scan 180 scanning
microscope with a link-System.
- precipitation of barium
sulphate ( using sulphuric acid
or sodium sulphate solution)
and barium carbonate { using
sodium carbonate solution)
from water extracts of salt
wastes.
- approximate spectral a-
nalyse of barium sulphate and
barium carbonate, using a Oarl
Zeiss-Jena PGS-type spectro-
photometer. •
- X-ray analyse of barium
carbonate, making use of a
Oarl Zeiss-Jena TUR M-62 appa-
ratus { radiation Cu^ )
- thermogravimetry of ba-
rium carbonate with the use of
a Q-150 OD Paulik-Erdey deri-
vatograph made by MOM Budapest.
- purity determinations
for barium sulphate and barium
carbonate according to the fol-
lowing standards: PN-59/C-
80250, ZN-54/M and PCh/05-228.
PROBLEMS ENCOUNTERED
Barium concentrations in ,
salt wastes, water extracts and
extraction residues were deter-
mined by gravimetry and atomic
absorption. The gravimetric me-
thod, in which barium,is preci-
pitated by sulphuric acid, was
found to be recommendable for
water extracts only. Determina-
tion of barium by the gravimet-
ric method in solution after
mineralization of salt wastes
or in the residue from extrac-
tion is characterized by a
considerable error which should
be attributed to the co-preci-
pitation of other compounds
present in the solution. Fur-
thermore, approximate spectral
analyses have shown that the
barium 'sulphate precipitate
contains Sr,11,Fe,Na,Ca, Si,Zn,
Pb,Mg,Mn and Gr in amounts
grather than 10"*2 dry wt.%.
Thus, it is the atomic ab-
sorption method that should .be
recommended when mineralised
salt wastes or extraction re-
sidues are involved.
RESULTS
Table 1 gives the chemical
composition of two SH-960 salt
waste samples. As shown by
these data, barium and iron
occur at the highest concent-
rations.
Table 1. Chemical composition
of two salt waste
samples ( dry ,wt... %}.
Metal Sample 1 Sample 2
Ba
Pe
Cr
Mn :
Sr
Fa
K
Ca
34.86
30.55
1.98
0.18
0.12
0.36
0.51
0.73
36.69
2,1.4.9
0.06
0.16
0.14
0.58
0.49
. 0.72
Mg,PbjZn,Ni,Cu,Cd and Co have
not been included, because
they are found in amounts below
0.04 dry wt. %.
Barium content in salt was-
tes accounts for 64,.6 to 68.0 %
of its content in fresh harde-
ning salts.
Comparison of results for
single-stage extraction and
multi-stage extraction.shows
533
-------
a distinctly higher effective-
ness of the latter. It has
been found that three stages
are sufficient to yield satis-
factory effects. But it is on-
ly the first extract that con-
tains appropriate "barium con-
centrations to enable recovery
of barium carbonate or barium
sulphate. The second and third
extract should be concentrated.
And this may be achieved by
reusing them for the first ex-
traction of a successive por-
tion of wastes. In the case of
Sample 1, the residue from
single-stage extraction amoun-
ted to 44.28 dry wt.# of the
initial value and displayed
barium concentration accoun-
ting for 8 % of the initial
content. The data obtained for
the residues from multi-stage
extraction were 39.93 dry wt.#
and 4.10 % respectively.
Non-extracted barium persisted
exclusively in the form of low
water-soluble carbonate and
oxide, which was also confir-
med by microscopic examina-
tions and X-ray analyses.
Figures 1 through 9 give
micrographs and maps showing
the surface distribution of
some elements on waste parti-
cles and in residues from sin-
gle- and multi-stage extrac-
tion. They reveal a noticeable
abatement of barium content
and an increasing contribution
of iron to the residues from
multi-stage extraction { as
compared to the remaining two
samples ) .
Technological investiga-
tions on the precipitation of
barium sulphate from water ex-
tracts have shown that it is
necessary to use reacting sub-
stances in slight excess
( 2-4 % ) as compared to stoi-
Figure 1. Backscattered elect-
rons image of SH-960
salt waste.
Figure 2. Distribution of Ba
in the region of
Fig. 1.
Figure 3. Distribution of Fe
in the region of
Fig. 1 .
534
-------
Figure 4. Backscattered elec-
trons image of 3H-960
salt waste after sin-
gle-stage extraction.
Figure 7. Backscattered elect-
rons image of SH-960
salt waste after mul-
ti-stage extraction.
Figure 5. Distribution of BaV(V
in the region of
Fig. 4.
Figure 8. Distribution of Ba,
in the region of *
Fig. 7.
Figure 6. Distribution of Fe
in the region of
Fig. 4.
Figure 9. Distribution of Fe
in the region of
Fig. 7.
536
-------
chiometric doses, i.e.
0.744 g H2S04/g Ba and
1.075 g Na2S04/g Ba .
The disadvantage of using sul-
phuric acid is a strong acidi-
fication of the extract {pH 1.4)
and of the water from barium
sulphate rinsing [ pH 2.4) .
The fine-crystalline barium
sulphate sediment has a white
colour and a water content of
about 40.5 % after decantation
of the post-reaction solution.
Rinsed barium sulphate con-
tains insignificant amounts of
impurities such as Sr,Si,Al,
Ga and Na, but these occur at
concentrations below the admi-
ssible levels for pure product.
Barium carbonate precipita-
tion required application of
sodium carbonate in 10 % ex-
cess with respect to the stoi-
chiometric dose,i.e.
0.845 g Na2G05/g Ba .
The major impurities found in
the barium carbonate sediment
are as follows; sodium carbo-
nate (which can be removed to
a large extent by rinsing) ,
strontium carbonate and cal-
cium carbonate ( both present
in amounts below the admissi-
ble levels for pure productl .
The water content of the ba-
rium carbonate sediment appro-
ached 75 %• The pH level in
the effluent from precipita-
tion was about 10, whereas
that of the rinsing water ran-
ged between 8.3 and 9.4.
The flow chart and mass ba-
lance of barium salt recovery
is given in Figure 10.
Apart from the recovered
product, i.e. barium sulphate
or barium carbonate, both
technological systems produce
secondary pollutants which call
for adequate treatment.
These are as follows:
- residues from water extra-
ction, which take the form of
fine-grained sediments contai-
ning predominantly very fine
iron fillings and non-extracted
barium ( persisting in carbonate
or oxide forms ) . Wastes of
that Icind should be dewatered
before they are stored on spe-
cial dumping sites0 Non-extra-
cted barium may be recovered
by dissolution in sulphuric
acid with simultaneous preci-
pitation of barium sulphate.
Ferrous sulphate persisting, in
the solution can be recovered
either by crystallization yiel-
ding FeS04»7 H20 or by precipi-
tation with calcium hydroxide.
- brine produced during pre-
cipitation of barium sulphate
or barium carbonate from the
extract is practically impossi-
ble to remove by conventional
methods. The only way to remove
this pollutant is a controlled
discharge ,of the solution into
the sewer system. There may al-
so be involved dilution with
water from rinsing of the reco-
vered barium salts. Some part
of the rinsing water can be re-
circulated and reused for ex-
traction ( after discarding the
first strongly polluted bath).
The investigations have
shown that recovery of pure ba-
rium salts from spent SH-960
hardening salts is relatively
easy to achieve. The amount of
barium chloride used for the
manufacture of hardening salts
accounts for some 5 % of the
total barium compounds used in
Poland. Barite, the starting
substance in the manufacture of
barium compounds, is now being
536
-------
WASTE AND SPENT HARDENING SALTS
1000 kg (358 kg Ba )
SEGREGATION. STORAGE
MILLING - Particles < 2mm
RETENTION
BASIN I
WATER EXTRACTION , MIXING
SEDIMENTAT-ION
Extract ll°+III0
4.7m3+4,8m3
Extract )°
19 m3
I 324 kg Ba
Water
10-20m3,5m3,5m3
1000 kg water
Extraction 423 kg solids
260 kg Fe
34kg Ba
residue
RETENTION BASIN II
DEWAT BRING
Filtrate
BaC03 RECOVERY
BaS04 RECOVERY
302.5 kg
REACTION BASIN
MIXING,
SEDIMENTATION
Sewer
I H2S04 266.4 kg
i |Na2S04 384.9 kg
REACTION BASIN
MIXING,
SEDIMENTATION
Post - reaction solutions
RETENTION BASIN III
pH CONTROL
RINSING
BaC03 SEDIMENT
I
Rinsings
DE WATERING
L
Filtrate
Cake 1123 kg
SECURE
LANDFILL,
H2S04 SOLUBILl-
ZING WITH PRE-
CIPITATION OF
57 kg
^ Cake
_
Filtrate
RINSING
BaS04 SEDIMENT
Rinsings
-H-
..
j CRYSTALLIZATION .[
| OF FeS04- 7H20 |
[ __ _l2i1_kl__J
DEWATERING
Filtrate
DRYING
( -- — _._ ___ .
i LIME TREATMENT!
! DEWATERING ~|
DRYING
Filtrate
Cake
REUSE OF
BaC03 or BaS04
466 kg 551 kg +57 kg
Figure 10. SIMPLIFIED FLOW CHART AND MASS BALANCE OF BARIUM SALTS
RECOVERY
537
-------
partly imported from the free
foreign-exchange zone. Hence,
barium recovery from wastes may
radically reduce a high-cost
import.
Hardening salts are produced
by a number of plants scattered
throughout the country. It is
obvious that this scattering
makes the processing of those
wastes a difficult task. A ra-
tional management of barium re-
covery calls for a nation-wide
(or, at least, a macroregional)
system. The most advantageous
and the easiest method of uti-
lizing waste barium compounds
is to return them to the manu-
facturer of barium salts for
appropriate processing.
The industrial plant wherein
waste salts originate should be
obligated to return these by
free door-to-door delivery. It
also seems recommendable to put
the waste originating plant un-
der an obligation to deliver
wastes and spent salts as a
prerequisite to enable purchase
of brand fresh salts. The ad-
vantages may be as follows: mo-
re effective control of spent
hardening salts management, ma-
ximization of barium recovery,
and smooth delivery of wastes
for processing. Preliminary a-
nalyses have revealed that the
recovery of barium salts from
wastes involves significantly
lower costs than their manufac-
ture on the barite basis.
Another alternative solu-
tion to the barium recovery
problem consists in incorpora-
ting a special line for the
processing of barium-containing
wastes in the macroregional
stations of hazardous waste ma-
nagement which are now under
design.
The lanfilling of barium
wastes is neither rational
(when considering economic as-
pects) nor recommendable ( when
taking into account environmen-
tal pollution control) despite
the fact that the direct landfi-
lling costs are lower than the
processing costs.
AGKWOWGLEMENTS
This study has been supported
from the funds of the Institute
of Environment Protection Engi-
neering, Technical University of
Wrociaw.
The authors are greatly inde-
bted to lidia Pe.kalska,D.Sc. and
Marek Maciejewski,D.Sc. for
their valuable co-operation.
REFERENCES
1. Kempa,E.,Szpadt,R.,l985,
A Decision Model Resulting
from the Classification of
Hazardous rfaste, In: Prop.
Intern. Conf. on New Front.
for Hazard, rfaste Manag.,
Pittsburgh PA,pp.171-178.
2. Miiller,W. ,1978, Aufarbeitung
von Hartesalzruckstanden.
In: Materialien 2/78. Salze
und salzhaltige losungen,
Erich Schmidt Verlag Berlin,
pp. 29-37.
3. 3chenkel,¥.,1983, Sonderab-
fallbeseitigung in der BRD,
Wasser. JLuft und Betrieb.
Vol.27, pp. 47-51
4. Sebastian,M. and R.Szpadt,
1986, Regeneration, Treat-
ment and Disposal of the
Spent Hardening Salts, Rep.
of the Inst. of Env. Prot.
Eng., Techn. Univ. of Wroclaw,
No 3PR 44/86, [ in Polish,
unpublished) .
Disclaimer
The work described in this paper
was not funded by the U.S. Envi-
ronmental Protection Agency.
The contents do not necessarily
reflect the views of the Agency
and no official endorsement
should be inferred.
538
-------
ECONOMIC EVALUATION OF SOURCE REDUCTION PROJECTS
David Butler
Carl Fromm, P.E.
Christopher Timm, P.E.
Jacobs Engineering Group Inc.
251 South Lake Avenue
Pasadena, CA 91101
ABSTRACT
This paoer examines costs and savings to a firm that are associated with
source reduction projects. The types of operational costs impacted by such
projects are identified and discussed with respect to their importance to
capital project evaluation. Two examples of waste reduction projects are
provided to illustrate the discussion.
INTRODUCTION
Recent legislative and regula-
tory emphasis on controlling the
management of hazardous waste has
escalated the current and
anticipated future costs to firms of
handling their process byproducts.
According to The New York Times, the
chemical waste management industry
has entered a period of
unprecedented growth and profit
visibility, driven principally by
government regulation (1). Manage-
ment discussions in the annual
reports of the larger chemical waste
management firms indicate that these
companies have very nearly a free
hand in passing compliance costs on
to customers in the form of higher
prices (2). With no reasonable
limit on waste management costs in
sight, source reduction—the
reduction of waste in-process--is
becoming financially more attractive
to companies in waste-generating
industries.
This paoer identifies types of
operational costs and savings asso-
ciated with source reduction
projects and discusses their
relative importance to capital pro-
ject evaluation. Two case examples
of waste reduction projects are pro-
vided to illustrate the discussion.
PURPOSE
This paper highlights operating
costs that are impacted by source
reduction projects. The methods Of
project evaluation are already well
known. The intent of this discus-
sion is to demonstrate the
importance of incorporating these
additional cost considerations into
analyses of source reduction
projects.
For this effort, information
was drawn from the waste reduction
audit experience of Jacobs
Engineering.
.539
-------
APPROACH
Source reduction projects often
have costs and savinqs different
from those of other capital
projects. In practice, the poten-
tial value of most capital projects
has been established on the basis of
savings in raw materials costs;
savinqs in utilities, labor, and
maintenance costs; and enhanced
revenues throuqh the creation of
marketable byproducts. Source
reduction projects can impact these
same areas. However, the goal of
reducing waste at the source focuses
attention specifically on waste
generation costs: disposal fees;
fees/taxes on generators; waste
transoortation costs; on-site waste
storage and handling costs; predis-
posal treatment costs; permitting,
reporting, and recordkeeping costs;
and pollution and safety
liabilities. These costs were
largely ignored in the past because
the lack of an active governmental
presence in environmental affairs
allowed much smaller commitments of
company resources to the waste
management segment of company
operations. Recent hazardous waste
management requirements have caused
these costs to increase beyond pre-
vious proportions.
For the purpose of evaluating a
project to reduce waste quantities,
some types of costs (savings) are
larger and more easily quantified.
These are disposal fees, transporta-
tion costs, predisposal treatment
costs, raw materials costs, and
operation and maintenance costs.
These costs (savings) are usually
considered first because they have a
greater effect on project economics
and involve less effort to estimate
reliably. However, the other, "sec-
ondary" costs can gain importance
deoending on the type of project to
be evaluated.
Two case examples were chosen
to illustrate the role of easily
quantified and less easily
quantified costs in source reduction
project evaluation. In each case, a
fixed-price, fixed-dollar cash flow
projection was constructed, which
assumes no inflation and no change
in the real relationships among
costs. Inflation was netted out of
interest rates per the Fisher
formula (3). Fixed capital outlays
were depreciated according to
methods prescribed by recent federal
tax legislation. All projects are
assumed to begin construction on
July 1, 1987. For each case,
internal rate of return (IRR) and
payback period (PBP) were used as
measures of financial performance.
PROBLEMS ENCOUNTERED .
A fixed-price cash flow
projection ignores the effects that
real changes in prices would have on
project performance. For example,
the avoided cost of waste disposal
could rise against project operating
costs in the future (both costs cor-
rected for inflation), which would
serve to enhance source reduction
project performance. If avoided
costs are exoected to rise against
operating costs\ in real terms, then
fixed-price projections give conser-
vative estimates of project perform-
ance because they understate the
cash generation of the project.
However, they do eliminate the
uncertainty surrounding forecasts of
future prices.
RESULTS
Case 1: Secondary Solvent Recovery
A resin-compounding operation
at a pharmaceutical company uses
1.,1,1-trichloroethane solvent for
equipment cleaning. The present
configuration uses a single-stage
540
-------
atmospheric still for solvent
recovery. The still recovers 92
percent of the 3,455 Ibs of spent
solvent feed per day. The still
bottoms, which contain 20 percent
solids by weight, are sent to a TSD
facility for solidification prior to
landfill ing.
The company is investigating
the feasibility of adding a
secondary recovery system to produce
a nearly solvent-free, "dry" cake
consisting - of filler solids and
polymerized resin. It is proposed
that a scraped-drum evaporator be
evaluated for this application.
Spent solvent would be fed onto a
heated drum as a thin coating.
Solvent vapors would be collected
and condensed into a receiver tank.
The residue on the drum would be
scraped off by a doctor blade
resting on the drum surface and
carried away for disposal. Design
and construction of the system would
require 3 months.
The current and proposed
solvent recovery schemes, along with
the associated mass balance, are
depicted in the block flow diagram
in Figure 1.
The estimated capital outlay,
including an allowance for contin-
gencies, is $69,450. Incremental
operating cost is estimated at
$12,340 per year. The value of raw
material offset by the recovered
solvent is $23,085. Avoided waste
disposal cost is $12,770. Waste
disposal cost is reduced both
because there is less volume of
waste and because the new byproduct
is a solid rather than a liquid.
The project is expected to require 3
months for implementation.
Table 1 reports the economic
performance measures for this
project. The internal rate of re-
turn for this project is calculated
to be 32.37%. The project payback
period is 3.3 years. To highlight
the effect of avoided disposal cost
on project economic performance,
avoided disposal cost was removed in
a subsequent evaluation. Internal
rate of return fell to 8.37% and
payback period was lengthened to 6.9
years. These would generally be
considered as indications of poor
performance. Therefore, • the
scraped-drum evaporator cannot be
justified on the basis of recovered
solvent alone. The presence of sig-
nificant avoided disposal cost
allows the scraped-drum evaporator
project to be seriously considered
as an alternative to continued
solvent waste generation.
Table 1. Summary of Economic Performance Measures, Secondary Solvent
Recovery
Internal Rate
of, Return («)
Payback
Period lyrs)
Including Avoided
Disposal Costs
Excluding Avoided
Disposal Costs
32.37
8.37
3.3
6.9
541
-------
PROCESS EQUIPMENT
CLEANING
PRIMARY RECOVERY
(ATMOSPHERIC STILL)
EXISTING
PLANNED
SECONDARY RECOVERY
(SCRAPED DRUM EVAPORATOR)
TO LANDFILL
Stream 1
Solvent 3,455
Resin 30
Filler 76
Total, Ibs/day 3,551
270
30
76
376
27
30
76
133
243
0
0
243
3,185
0
0
3,185
Figure 1. Block Flow Diagram and Mass Balance for Solvent Recovery System
542
-------
Case 2: On-site Thermal Oxidation
A manufacturer of electronic
components sends approximately
125,000 gallons per year of chlori-
nated and non-chlorinated solvent
waste for off-site management. The
cost of having the waste managed
off-site has grown to nearly
$250,000 per year, including
disposal charges, taxes, and fees,
and now represents a sizeable por-
tion of manufacturing cost. The
company is investigating ways to re-
duce this cost and is seriously con-
sidering on-site thermal oxidation.
Two configurations for a
thermal oxidation system are
proposed. The first, Alternative A,
is a thermal oxidizer with a boiler
for ancillary heat recovery. Alter-
native 8 is a thermal oxidizer
alone. Each system would burn only
non-chlorinated solvents, which com-
prise somewhat more than 90 percent
of the facility's total solvent
waste generation.
Total capital outlay is
estimated at $560,300 for
Alternative A, $143,000 of which is
estimated permitting cost. Alterna-
tive A would require 1 year to build
and permit. The outlay for Alterna-
tive B is estimated at $658,000, of
which $328,000 is permitting cost.
The reason for the difference in
permitting costs is that Alternative
A, because of its provision for heat
recovery, can be permitted as a
resource recovery facility, whereas
Alternative B must be permitted as a
hazardous waste incinerator. Alter-
native B is expected to require 2.5
years to construct and permit.
Table 2 displays the breakdown of
the permitting cost estimates. The
midpoints of the cost ranges were
used in the economic feasibility
analysis.
To establish a benchmark for
comparison, the alternatives were
first evaluated without permitting
costs. The permitting costs were
subsequently added to the capital
outlay amounts and the alternatives
were reevaluated.
Table 3 shows the result of
this evaluation. Without permitting
costs, both alternatives exhibit un-
exceptional economic performance
with regard to internal rate of re-
turn, and each is outside manufac-
turing industry norms for payback
period of 2-3 years maximum. When
permitting costs are included, the
projected performance of each
project is reduced substantially,
though Alternative A still exhibits
average economic performance. In
the case of Alternative B, the pay-
back period has more than doubled.
It should be noted that
Alternative B is expected to require
1.5 years longer to permit than
Alternative A. The permitting costs
in Table 1 do not include the cost
of this delay to the company if it
chooses Alternative B. To approxi-
mate the consequence of implementing
Alternative B over Alternative A in
this instance, the cost of disposal
during the additional 1.5 years is
entered into the operating cash
flows for Alternative B. The result
is an internal rate of return of
3.81% and a payback period of 12.1
years. These figures are more use-
ful for evaluating incineration
alone against incineration with heat
recovery in this instance.
Summary and Conclusion
The costs of waste generation
are no longer a negligible part of
overall operating cost. Two cases
have been outlined where waste gen-
eration costs figure importantly in
543
-------
Table 2. Permitting Costs Associated with the Thermal Oxidizer
Resource
Recovery Facility
Hazardous
Waste Incinerator
1. Prepare Part B Application
2. Agency Review and Response
to Notice of Deficiencies
3. Trial Burn Plan
4. Formal Trial Burn
$ 25,000
$ 4,000-10,000
$ 1.5,000-30,000
5. Test Burn in Lieu of Formal
Trial Burn
6. Public Hearings/Community
Awareness/Local Permitting $ 30,000 (a)
7. Risk Assessment (if required) $ 40.000 max
Subtotal
8. Contingency for Permitting
Uncertainties
9. Optional Additional Monitoring
Instrumentation Costs $
10. State Agency Permitting Cost _$
$ 74,000-135,000
$ 23,000
12,000 max
10,000
TOTAL
$107,000-180,000
$
25,000
$ 10,000-16,000
$ 15,000-30,000
$ 55,000-200,000
depending on number
of tests required.
$ 50,000
$ 25,000-40,000
$155,000-361,000
$
$
54,000
12,000 max
10,000
$219,000-437,000
project evaluation. In the first
case, the magnitude of avoided dis-
posal cost supports secondary
solvent recovery. In the second
case, each > project alternative
involves significant avoided
disposal cost, but the costs and
delays associated with permitting a
hazardous waste incinerator clearly
eliminate incineration alone as an
option for on-site waste management.
These two cases also serve to
indicate how recent regulation has
enhanced the economics of source
reduction. Both projects stand on
the basis of avoided disposal cost.
By changing the relative prices
associated with waste generation and
management, regulation has
encouraged firms to implement source
reduction measures in order to main-
tain production cost efficiency. It
is apparent thai; source reduction in
many cases could represent a lower-
cost alternative to continued waste
generation.
NOTES AND REFERENCES
1. Wiggins, P., "Waste Control:
Strong Outlook," The New York
Times, September 8, 1986.
2. See, for example, Waste Manage-
ment Inc., 1985 Annual Report,
p. 51: "Competitive conditions
and governmental regulations
permitting, the Company expects
to adjust its prices to recog-
nize future cost increases."
See also International Technol-
544
-------
Table 3. Summary of Costs and Benefits, On-site Thermal Oxidation
Alternative
A
Benefits
Recovered Heat 43,400
Avoided Disposal Cost 185,360
, Total Benefits 228,760
Operating costs
Raw Materials & Utilities 6,394
Overhead . 27,000
Operating & Maintenance Labor 52,412
Insurance & Property Taxes 13,562
Total Operating Costs 99,368
Performance without Permitting Costs
Internal Rate of Return (%} 22.45
Payback Period (yrs) 3.9
Performance with Permitting Costs
Internal Rate of Return (*) 15.99
Payback Period (hrs) 5.5
185,360
185,360
6,3.14
18,000
36,920
10,725
71,959
17.54
3.9
7.70
8.4
3.
ogy Corporation's 1986 Annual
Report, p. 16: "The substan-
tial costs associated with (a
major 'investment program for
complying with the new RCRA
requirements), coupled with in-
creased taxation on waste
disposal, ,has resulted in sub-
stantial periodic price
increases. These are expected
to continue as new regulations
impose more stringment
pretreatment standards on dis-
posal to landfill."
(1 + r) = (1 + i)/(l + n),
where
r = real interest rate
i = nominal interest rate
n = rate of inflation
Disclaimer
The work described in this paper was
not funded by the U.S. Environmental
Protection Agency. The^contents, do
not necessarily^reflect the views of
the Agency and no off.icial endorse-
.ment should be inferred.
545
-------
-------
MINIMIZATION OF SOLVENT WASTES FROM
AN ELECTRONIC CAPACITOR MANUFACTURING PROCESS
Harry M. Freeman
Hazardous Waste Engineering
Research Laboratory
Cincinnati, Ohio 45268
Michael S. Callahan
Jacobs Engineering Group Inc.
Pasadena, CA 91101
James R. Teuscher
SFE Techno!og^es, Inc.
San Fernando, CA 91340
Carl H. Fromm
Jacobs Engineering Group Inc.
Pasadena, CA 91101
ABSTRACT
The paper summarizes the results and recommendations of a waste
minimization audit carried out to identify opportunities for reducing solvent
wastes from an electronic capacitor manufacturing process. The major solvent
waste generating operations audited included the cleaning of various
equipment with RM-513 (a proprietary solvent) and with recycled
1,1,1-trichlorethane (TCA); general cleaning with isopropyl alcohol and with
recycled TCA; and the on-site recovery of spent TCA. The audit resulted in
22 waste reduction options being postulated and seven selected for further
investigation. This paper is extracted from the EPA report, Case Studies,of
Minimization of Solvent Waste from Parts Cleaning^ and from Electronic
Capacitor Manufacture Operations presently under review forclearance from
HWERL.
INTRODUCTION AND PURPOSE
In order to increase the accep-
tance of waste minimization by in-
dustrial hazardous waste generators,
the EPA has supported the develop-
ment of a procedure for facilitating
identification of opportunities for
waste reduction.
The general procedure is
summarized in Table 1. (A manual
based on the procedure is currently
under preparation by the EPA. The
manual will be available from HWERL,
Cincinnati in the fall of 1987).
The case study summarized in this
paper was one of five such studies
carried out to test the auditing
procedure.
performed in
APPROACH
The work described was
the fall of 1986.
The facility chosen for the
study is a major manufacturer of
multilayer ceramic capacitors used
primarily by the telecommunications
and military electronics industries.
Production operations are performed
in two separate buildings located
within close proximity to each
other. Ceramic materials are formu-
lated in an Annex building and then
transferred to the Main Facility
where the capacitors are formed.
Various finishing operations are
performed at both buildings.
547
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Table 1. Recommended Waste Minimization Audit Procedure
Program
Phase
Activities
Product
Pre-Audit 1. Preparation for the audit
2. Pre-audit meeting and
inspection •
3. Data compilation and
waste stream selection
o needs list/inspection agenda
o notes
o facility and process
description
o waste description
o rationale for selection
Audit
4. Facility inspection
5. Generation of a compre-
hensive set of WM options
6. Options evaluation
7. Selection of options for
feasibility analyses
o
o
notes
list of proposed options
with written rationale
independent options ratings
by audit team and by
plant personnel followed by
joint review
list of selected options
options interim report
Post-Audit 8. Technical and economic
feasibility analysis
9. Final report preparation
study or budget grade
estimates of capital and
operating costs; profit-
ability analysis
final report with
recommendations
Major operations are depicted
schematically in the block flow
diagram (Figure 1).
The solvent wastes are generated
mainly by various equipment cleaning
operations:
o ball mill cleaning and off-spec
slurry disposal;
o cleaning of the transfer pots;
o off-spec slurry disposal, clean-
ing and flushing of the slurry
application system;
o general cleaning;
o still bottoms from the on-site
TCA still.
The most common solvents used
for cleaning include 1,1,1-trichlor-
ethane (TCA), RM-513 (a proprietary
solvent), and isopropyl alcohol
(IPA).
Development and Screening of Solvent
Haste Minimization Options
Each main solvent cleaning
operation was scrutinized by the
audit team so as to develop a list
of options that would reduce or
eliminate waste generation. at
source. The focus was mainly on
recycling of spent cleaning solvent;
such approach was deemed as the most
548
-------
effective short-term option. The
long-term solutions (e.g. develop-
ment of non-solvent formulations)
could not be meaningfully addressed
in this study.
Table 2 lists the various waste
minimization options identified by
the audit team for each operation.
For initial screening, each option
was rated on a scale of zero (low)
to ten (high) for its waste reduc-
tion effectiveness, extent of
current use, and future application
potential. After rating each
option, the current and future re-
duction indices were determined.
Following discussion with
facility personnel, several of the
options described above were
selected for further investigation
based on their high future reduction
index. The options evaluated in
further detail were:
o Ball Mill and Slurry Application
Wastes:
Segregate and recycle RM-513
based off-spec slurry.
o Ball Mill, Transfer Pots, and
Slurry Application Wastes!
Segregate,standardize,and recy-
cle cleaning solvents.
o Slurry Application Wastes:
Segregate arid recycle RM-513
flushing solvent.
o Slurry Application Wastes:
Convertapplicationsystem
filters to bag/wire mesh type.
o General Cleaning Wastes;
Segregate and recycle isopropyl
alcohol waste.
o TCA Primary Recovery Wastes:
Install secondary recovery
system.
Figure 2 partially depicts a
proposed . scheme for segregation and
recycle of cleaning solvents based
on the . options indicated. Para-
graphs below detail the results
of feasibility analysis performed
for each option.
Ball Mill/Slurry Application Wastes
By segregating the off-spec
slurry waste from the other wastes
generated at the ball mill and
slurry application operations, 20
gallons per week of RM-513 waste
would be rendered recyclable.
Segregation would require that
separate storage containers be pro-
vided to the operators. Proper
training of the operators to use the
special storage containers should
not be a problem, since the facility
has recently implemented a success-
ful waste segregation program.
Once this waste is segregated,
a small 55-gallon batch distillation
unit could be procured for the
recovery of RM-513). The cost of
procuring and installing an auto-
mated still is estimated to be
$25,750. Annual savings based on
recovering 14.4 gallons of solvent
per week and reducing waste disposal
costs would amount to $6,040. This
equates to a payback period of 4.3
years. Since this period exceeds
the required hurdle rate of 3.0
years, procurement of a still to re-
cycle this waste stream alone cannot
be justified.
Ball Mi 11/Transfer Pots/Slurry
Application Wastes"
After segregating the wastes
according to solvent type (RM-513 or
TCA), efforts should be made to
standardize the type of solvent used
for cleaning. Figure 2 presents a
modified block flow diagram for
standardizing the solvent used for
cleaning the equipment which handles
RM-513 based materials. The follow-
ing major changes to the currently
employed cleaning scheme are
proposed:
549
-------
o Primary ball mill rinse would use
RM-513, instead of TCA.
o Primary transfer pot cleaning
would use RM-513, instead of TCA.
o Slurry application pot rinsing
would use RM-513, instead of TCA.
Once these changes are made,
the amount of RM-513 based waste
will increase so that the economic
justification for procuring a still
is improved. Assuming that all 50
gallons per week of waste can be
converted to RM-513 based waste,
annual savings of $19,130 would
result. This equates to an accepta-
ble payback period of 1.3 years.
Slurry Application Wastes - Solvent
Flush
By segregating the flushing
waste from the other wastes that are
sent off-site for incineration, 14.5
gallons per week of RM-513 could be
recovered by use of a small batch
still. The cost of procuring and
installing an automated still is
estimated to be $25,750. Annual
savings based on recovering RM-513
and reducing waste disposal costs
would amount to $5,400. This
equates to a payback period of 4.8
years which makes this option, by
itself, economically infeasible.
Slurry Application Wastes - Filter
Cartridges
Waste containing spent car-
tridge spent filters could be
virtually eliminated by changing to
a wire mesh filter. A major
advantage of this style of filter is
that it is reusable and that no
filter housing replacement would be
necessary. The envisioned system
would consist of replacing the cur-
rent filters (4 per system) with
washable wire mesh filters and
adding a few valves to allow for
backwashing of the filters with the
solvent used for system flushing.
Based on a total installed cost of
$9,830 for all six systems, the
annual savings would amount to
$6,660. This equates to a payback
period of 1.5 years, making this a
viable option.
General Cleaning Wastes - Isopropyl
Alcohol
General facility cleaning
generates 94 gallons per week of
dirty isopropyl alcohol (IPA).
Since the overall quality of this
waste is unknown, it is assumed that
only 50 percent of the waste would
be amenable to recycling. The re-
maining 50 percent (assumed to be
too heavily contaminated to allow
for efficient recovery), would
continue to be sent off-site for
incineration. Included with this
waste would be the still bottoms
from IPA recovery.
Recycling of IPA waste is esti-
mated to save the facility $11,650
per year. Based on a total
installed cost of $25,750, the
resulting payback period is 2.2
years. Since this is less than the
required hurdle rate of 3.0 years,
and since it was conservatively as-
sumed that only 50 percent of the
waste was recyclable, this option is
considered viable. For IPA waste
that was too heavily contaminated
with water to allow for recycling,
drying with unslaked lime could be
performed. While this would
increase the amount of recyclable
IPA, the effects of increased solids
disposal would have to be addressed.
TCA Primary Recovery Wastes
The facility currently generates
55 gallons per week of still bottoms
from the operation of their TCA
primary recovery system. This waste
is sent off-site for additional
550
-------
recovery of TCA (estimated to be 65
percent). Use of an on-site still
that could achieve a secondary
recovery of 80 percent would reduce
annual costs by $7,100. Based on a
total installed cost of $25,750 for
a still, the resulting payback
period is 3.6 years.
In addition to the marginal
economic performance, the residuals
(distillation bottoms) may pose dis-
posal problems after November 8,
1986 if the TCA level exceeds
10,000 ppm. It is recommended that
the solvent content of residuals be
determined experimentally before the
secondary recovery of the still
bottoms is attempted on a larger
scale.
SUMMARY
Five major solvent waste produ-
cing operations were investigated
during the initial audit. The five
operations involved ball milling,
slurry transfer pot cleaning,
cleaning of the slurry application
systems, general cleaning performed
throughout the facility, and opera-
tion of the on-site TCA still.
Waste minimization options were for-
mulated for each operation, with the
main focus placed on ways to
increase the recyclability of the
waste produced. These options were
then tabulated and . rated. From
these ratings, options were selected
for additional economic analysis.
The results of this analysis are
shown in Table 3.
Many of the options discussed
above rely on the use of a small
batch still for solvent recovery.
Since the still operates in a batch
mode, all of these waste streams can
be separately .processed in the same
unit. By dividing the capital cost
for one system by the savings resul-
ting from implementation of the four
options indicated in Table 3, the
overall payback period is calculated
at 0.9 years, as opposed to periods
ranging from 2.2 to 4.8 years for
each option individually. By incor-
poration of the above-mentioned
measures, the facility can reduce
solvent waste generation by 54 per-
cent (5,810 gallons per year) at an
estimated annual savings of $30,190.
In summary, the economic and
technical feasibility for on-site
reclamation of cleaning solvent is
demonstrated.
DISCLAIMER
The work described in this paper was
not funded by the U.S. Environmental
Protection Agency. The contents do
not necessarily reflect the views of
the Agency and no official endorsement
should be inferred.
551
-------
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SELECTION OF A MOBILE INCINERATION SYSTEM
John C. Reed
Steven R. Strauss
James D. Cobb
Illinois Environmental Protection Agency
Springfield, Illinois 62794-9276
ABSTRACT
Recognizing the need to develop a mobile incineration technology
in the State of Illinois, the Illinois Environmental Protection Agency
("IEPA" or "Agency") formed an inter-Agency task force in 1984
consisting of members from the divisions of Land Pollution Control, Air
Pollution Control and the Office of Chemical Safety. A series of
meetings with interest contractors was initiated, site visits were
held, a Request for Qualifications was issued and in the latter part of
1985, a Request for Proposal ("RFP") for a Remedial Action utilizing a
mobile incineration system was issued by the Agency. After a thorough
evaluation of the proposals submitted, a contract was awarded to Roy P.
Weston, Inc. to mobilize a mobile incineration system at a designated
site and conduct remediation activities. The unit was mobilized in May
of 1987 and treatment of contaminated soils is expected to be completed
by the end of 1987.
This paper describes the background of the selection of the mobile
incineration technology as it has been developed by the IEPA. In the
course of this selection process, IEPA has developed evaluation tools
and techniques that will be useful to others involved in hazardous
waste cleanups. The IEPA believes that the information and methods
described here will ensure the selection of the best treatment system
with the lowest probability of foreseeable difficulties.
INTRODUCTION
For many years, the most
common practice for disposing of
hazardous substances was dumping
into available landfills. Now,
the need for technological
alternatives to landfills is well
recognized. This need has become
more acute with the advent of the
Comprehensive Environmental
Response, Compensation and
Liability Act, the discovery of
many nonpermitted treatment,
storage and disposal facilities
requiring remediation of
significant amounts of
contaminated soil, sludge and
liquids, and the enactment in
Illinois of a legislative mandate
requiring that hazardous waste
streams may be landfilled only
after a demonstration has been
made that recycling, incineration
or chemical, physical or
biological treatment of the waste
is not technologically feasible or
economically reasonable
(1).Incineration and other means
of thermal destruction have been
555
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well accepted as attractive
alternatives for disposing of
hazardous substances but are
costly and suffer from the
"NIMBY" (not in my backyard)
syndrome. Thus, the concept of a
mobile incineration system that
can be transported from one
hazardous waste site to another
becomes very attractive. The
hazardous substances can be
treated on site, thereby avoiding
the necessity for transport of
the waste to a stationary
incineration facility or
landfill; the unit is on site for
a limited period of time
correcting a known problem and
then moved, thereby avoiding the
public resistance to a stationary
facility; the stationary
incinerator facilities are not
backlogged by a deluge of
hazardous substances emanating
from a hazardous waste cleanup
(often between 7000 and 15,000
tons of contaminated materials)
and the cost of treatment of the
waste on site with a mobile
incineration system appears to be
significantly less than
transportation and treatment of
waste to a stationary
incineration facility.
ORIGINAL CONCEPT
Stationary incineration has
been long considered an adequate
disposal technology and many
units have been built and
operated (2). The original
concept of mobile incineration
technology was first actively
investigated by the USEPA in
Edison, N.J. with a
trailer-mounted rotary kiln (3).
The first field test of
USEPA's mobile incineration
system was at the Denney Farm
site in southwest Missouri
(McDowell, Missouri)(3), This
field test gives a guide to the
various problems that can be
encountered by a mobile
incinerator and has been very
helpful in the Agency's own
evaluation of the process.
BACKGROUND OF SELECTION PROCESS
The early background of the
selection process has been
described in a previous paper
(4). In October, 1984, a task
force was formed at the IEPA
consisting of the divisions of
Land Pollution Control, Air
Pollution Control and the Office
of Chemical Safety to consider the
feasibility and appropriate
technology for alternate treatment
technology at Superfund and "Clean
Illinois" sites. "Clean Illinois"
is a state-funded program
analogous to the Superfund Program
at the federal level.
As a result of these efforts
in October, 1985, a Request for
Proposal ("RFP") to remediate a
specific site in Illinois
utilizing a mobile incineration
system was issued to prospective
bidders. The site proposed for
remediation was an abandoned
salvage yard containing
approximately 7000 tons of soils
contaminated with polychlorinated
biphenyls in concentrations up to
1650 PPM. Six bidders responded
to the RFP by submitting proposals
to the Agency.
EVALUATION FORMAT
An evaluation committee was
selected to evaluate the proposals
submitted in response to the RFP.
The evaluation committee consisted
of members from the Divisions of
land Pollution Control and Air
Pollution Control as well as a
consultant from a large private
556
-------
engineering company having
substantial on-hands experience
with incineration technology.
The committee evaluated the
technical adequacy of the
incineration system, the proposed
methodology for accomplishing the
scope of work, and the permitting
experience of the bidders. In
addition, inasmuch as the RFP
requested a turn-key type of
proposal, the Agency anticipated
the bidders being composed of a
composite group, consisting of an
incinerator
manufacturer/fabricator, an earth
moving remediation contractor and
an engineering company with
permitting experience.
Accordingly, the organization of
the bidder and the cohesiveness
of the proposal were evaluated.
An evaluation form was designed
to thoroughly examine the above
described components of the
bidder's proposals.
TECHNOLOGY OF THE MOBILE
INCINERATION SYSTEM .
The IEPA wanted as much
assurance as possible that the
incineration system ultimately
chosen would have a high
likelihood of success in the
field. Accordingly, the system
had to be designed to meet or
exceed the performance standards
established by the Toxic
Substances Control Act (TSCA) for
incineration of PCB's as well as
performance and operating
standards established by the Air
and Land Divisions of the
Agency. Process flow diagrams
and process and instrumentation
diagrams as well as lengthy
narratives were evaluated to
determine the capabilities of the
proposed systems.
The proposed control room of
each bidder was evaluated to be
certain monitoring with continuous
data recording would be done for
the parameters deemed essential by
the Agency, as well as contain an
automatic control system and shut
off system when operations of the
incinerator failed to meet
acceptable temperature and stack
gas concentrations. Additionally,
the waste capacity of the system
and backup and redundancy of the
system were evaluated. The Air
Pollution Control equipment was
evaluated utilizing descriptions,
specifications and drawings. Air
monitoring procedures and
equipment were evaluated. The
evaluation committee also
evaluated how the proposals dealt
with problems that had arisen in
the USEPA field test (4) such as
carryover of ash into the
secondary and combustion controls
to assure proper and complete
combustion.
The major technical
disparities among the proposals
were the level of sophistication
of the proposed control rooms,
vertical afterburners versus
horizontal afterburners, wet
scrubbers versus dry scrubbers,
waste throughput capacities,
energy efficiencies of the systems
and the types of air pollution
control equipment.
SCOPE OF WORK
The bidder's proposed
methodology to implement the
required work was evaluated.
Sampling techniques, laboratory
facilities, excavation techniques,
dust suppression techniques,
runoff control, treatment and
disposal of waste water and
ambient air monitoring were
evaluated. The type of variations
within the proposals dealt with
such issues as the extent of soil
sampling necessary at the
557
-------
excavation areas, extent of
sampling necessary of the ash
residues and the method of
analysis of both feed soils and
ash residues. Also, there were
variations in extent of ambient
air monitoring necessary to
detect particulate and organic
emissions.
Based upon the difficulty
encountered in evaluating certain
of the above criteria, the IEPA
concluded that the proposals
would have been more amenable to
comparison in certain areas if
the RFP had contained more
specificity. In addition, where
federal approval is necessary in
the permitting process, such as
TSGA, engaging in a dialogue with
federal officials early in the
process as to federal
requirements would have helped
facilitate the evaluation and
contracting process.
After the initial
evaluation, each of the bidders
was given an opportunity to make
a presentation of their proposal
to the evaluation committee. The
meetings gave the evaluators an
opportunity to ask the bidders
questions concerning the bidders'
proposals and receive needed
clarification. In addition, the
bidders had the opportunity to
meet the evaluation committee and
to accentuate these portions of
the proposal they felt the most
important. Finally, it provided
the evaluation committee an
opportunity to inquire and
discuss with the bidders the
types of unforeseen circumstances
that might occur at the site
which would cause delays and cost
adjustments. Issues affecting
the time schedules and cost
proposals of the bidders were the
availability of an adequate fuel
source, availability of
sufficient quantity of water of
requisite quality, excavating
into the ground water table, high
moisture content soils
necessitating higher residence
time, high or low BTU soils
affecting throughput in the
system, potential of contamination
of the field laboratory and the
advent of winter weather.
At the conclusion of the oral
presentation, the bidders were
given an opportunity to submit
clarifications to their proposals
which were discussed during the
presentations and their "last
best" bid, at which time the
bidders had the opportunity to
alter the cost proposal portion of
their proposals. I
The evaluation committee then
went through the score sheet a
final time to deal with any
changes in scoring arising from
the clarifications. The RFP
stated the technical criteria
would be evaluated independent of
the cost portions of the bidder's
proposals. The RFP also stated
that, to the extent that there
were no significant differences
among the proposals, price would
become increasingly significant.
The ultimate purpose of the
evaluation was to award a contract
to the bidder whose proposal was
the most advantageous to IEPA,
cost and all other factors
considered. Accordingly, the cost
proposals were evaluated and
weighed into the evaluation
process at the completion of the
technical evaluation.
Based upon the conclusions
derived from the evaluation
process described above, a
contract was awarded to Roy F.
Weston, Inc. of West Chester, PA.
The requisite permit and approvals
have been obtained and the
remediation is proceeding on
schedule.
558
-------
REFERENCES ,
1. Illinois Environmental
Protection Act, Section
39(h), 111. Rev. Stat. 1985
Ch. 111|, para. 1039(h)
2. Frankel, I., N. Sanders and
G. Vogel, March 1983, Survey
of the Incinerator
Manufacturing Industry,
Chemical Engineering
Progress, pp. 44-55.
3. Freestone, F. et. al., 1986,
Evaluation of On-Site
Incineration for Cleanup of
Dioxin-Contaminated
Materials, In: Land
Disposal, Remedial Action,
Incineration and Treatment of
Hazardous Waste. Proceedings of
Twelfth Annual Research Symposium,
EPA/600/9-86/022, Hazardous Waste
Engineering Research Laboratory,
Cincinnati, OH., pp. 298-318.
4. Reed, J.C., S.R. Strauss and
J.D. Cobb, 1986,
Considerations in selecting a
Transportable Thermal
Destruction Unit (TTDU), In:
Toxic and Hazardous Wastes.
Proceedings of the Eighteenth
Mid-Atlantic Industrial Waste
Conference. G.D. Boardman
(ed.)| Technomic Publishing
Co., Lancaster, PA., pp.
187-197.
Disclaimer
The work described in this paper was
not funded by the U.S. Environmental
Protection Agency. The contents do
not necessarily reflect the views of
the Agency and no official endorse-
ment should be inferred.
559
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-------
TRACING CONTAMINANT LEAKS USING BOREHOLE TELEVISION
Alan M. Jacobs
GEOPROBE
Pittsburgh, PA 15235, U.S.A.
ABSTRACT
Borehole television cameras are used to document stratigraphy or internal
structure of wells, and can detect the presence and movement of fluids or
solids. Cameras are designed for 2+-inch air- or water-filled boreholes. The
images can be titled on the screen and videotaped with voice-dubbed notation.
The tapes can be replayed for non-field personnel, permitting officials, and
in courtrooms. Television has the advantage over other geophysical methods of
downhole sensing in that one can actually see the features in question.
Contaminant leaks were investigated in 8 states. Monitoring wells had
been placed at site perimeters to sample water-supply aquifers. The wells
were installed with screens/slots at the aquifer horizons. Surface
contamination from perched ground-water zones above the slots were sometimes
caused by improper installation or damage to the well. Sometimes contaminants
were observed entering the well through the slots at the horizon of the
aquifer. Solids could be seen adhering to the casing, clogging the slots,
settling in water, and oozing into the well at splices. Gasoline, having a
different optical index of refraction from water, formed a visible layer
floating on water.
Additional ground-water information in uncased boreholes has been
collected by observing the water movement above and below the water level.
The water could be seen entering or leaving the borehole where the hole
intersects aquifers, fractures, and contacts between strata of different
permeabilities. Quantitative measurements of flow could be obtained by
duplicating the video image in the laboratory where a known flow—rate was
produced.
INTRODUCTION
Television camera probes are
presently being used to examine the
subsurface strata, ground water, and
the internal structure of well
casings, screens, and down-hole
instruments. This method allows
actual real-time images to be
monitored and recorded on videotape.
The replay can be viewed immediately
(no photo processing) or viewed
later by others not involved with
the field work, by permitting
agencies, and in the courts.
Since 1980, the author has been
asked to televise uncased boreholes
and completed wells in Maryland,
Tennessee, Louisiana, Pennsylvania,
New Jersey, Nevada, Virginia, and
California for the purpose of
evaluating the hydrogeology of a site
or to explain the movement of
contaminants at hazardous-waste
facilities and at cleanup sites.
This paper summarizes what is being
done using borehole television to
detect and assess the movement of
contaminants in ground water.
561
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FEATURES OF BOREHOLE TELEVISION
The borehole television camera
system used by GEOPROBE is
manufactured by the Westinghouse
Electric Corporation, Industrial and
Government Tube Division, in
Horseheads, New York. The camera
can transmit a clear,
high-resolution image to a surface
TV monitor for the insitu inspection
of subsurface conditions (1).
The closed-circuit TV system
(ETV-1252) consists of a camera head
(probe) and a camera control unit
(CCU) connected by a flexible
multilead underwater cable' (Figure
1). The probe contains a 16-mm
remote focus lens, a low-light level
Newvicon pickup tube, quartz-halogen
lighting on various attachments:
down-hole viewer, side-hole viewer
(with prism), combination down-hole
wide—angle and side—hole viewer
(with mirror), spotlight viewer
(with prism), and directional
spotlight (with prism and magnetic
compass). The CCU contains remote
focus and light-intensity controls.
The cable contains armored,
sheathed, and shielded bundles of
single conductors (24) and coaxials
(2), and is lowered and raised by an
electric-powered cable reel and
winch. This system is used with
other video equipment for
video-titling, tape recording, and
monitoring. The down-hole portions
of the system can operate under
water and in a dry hole. The probe
can be lowered and raised from air
to water and from water to air
without pausing. This ETV-1252 can
survey wells as small as 50 mm in
diameter and as deep as 150 meters.
In the field, a van functions
as a mobile TV studio (Figure 2).
The van protects the control,
monitoring, and recording units from
the elements. A sheave and boom
guides the cable off the reel, out
of the back of the van, and down the
hole. Inside the van, the operator
controls the descent/ascent, the
focus and light intensity, the video
recording, the audio-dubbing of
verbal notation, and the
video-titling using a 'character
generator (depth, date, location,
client, borehole number,
hydro-geologic features, etc.). The
amount of cable that is played out is
noted by observing markings on the
cable and entering depth values or
elevation by means of a keyboard.
Power (110 VAC) is provided by a
gasoline-powered alternator.
Because the image is in black
and white, the resolution is
three-times better than with a
similar color pickup tube. The
ETV-1252 can televise a strand of
wire only 1/3 the thickness of a
human hair. It can focus from
infinity down to the lens plate of
the camera probe. The 'high
resolut ion -and closeup focus enables
the camera to sit close to the object
being televised; thereby allowing
relatively clear images in murky
water.
The probe is made of stainless
steel, the down-hole attachments are
made of either stainless steel or
cast alluminum, and the cable sheath
can be made of various flexible
materials such as PVC, polyethylene,
and polyurethane.
MONITORING-WELL INSPECTION
Monitoring During Drilling and
Installation of Wells
During and after drilling,
portions of the hole are either cased
or uncased. In a cased hole the
side-wall bedrock or soil cannot be
viewed. The side walls can be
televised prior to the installation
of casing if the borehole can be kept
open without casing. Well casing can
be installed in stages with the upper
562
-------
part of the borehole cased to keep
the side walls from caving and the
lower part of the borehole uncased
for televiewing.
The camera can be introduced
into the hole during the drilling
operation (between runs) if
hollow-stem augers or wire-line
methods are employed to look at the
down-hole tools or peek out at the
rock or soil in the bit area. The
driller can usually guess about
down-hole conditions, but seeing the
situation first hand is more
reliable. The driller can suggest
the need for the camera during the
drilling operation depending on the
speed of drilling, bit resistance,
loss of circulation of drilling
fluids, tool drops, cuttings, etc.
The camera can also stand by
during the installation of the
casing and screens, the well
development, and the grouting to see
if materials are properly in place
before proceeding to the next step.
After completion of the
installation, the well can be
visually inspected by introducing
the camera into the completed well.
Water Level
The measurement of the water
level is usually accomplished by
lowering a probe down the hole
(Figure 3). The probe sends a
signal to the surface when it
touches the top of standing water.
Discrete readings can be taken
periodically in this manner. We
have noticed that the probe can be
triggered by moisture above the
static water level, thus giving an
erroneous reading. Perched water
sometimes enters the casing through
cracks or unsealed joints in the
casing and sets off the probe.
Droplets of water from condensation
(not associated with ground water)
can also trigger the probe. TV
monitoring of the water table and
comparison with the probing method
should be done periodically.
If continuous readings are
needed, a pulley can be installed
which balances a float with a
counterweight. The float rests on
the water surface. If water levels
change, th,e float and the
counterweight adjust and the rotation
of the pulley wheel moves a pen on a
continuous recording chart. If
unusual fluctuations are recorded,
the camera should be used to visually
check these fluctuations. One could
perform a 1- or 2-day surveillance of
the water table by videotaping the
view of the top of the water column.
Water Sampling
Contaminants in the water
column of a well are in solution or
suspension. Dissolved material will
come up with the water sample in a
representative concentration.
However, suspended material may not
be present i.n the water sample in a
representative concentration.
Suspended solids (including oily
residues) can stick to the sides of
the casing, side wall, or slots and
not come up with the water to be
analyzed, thus being
under - represented in the water
sample. Suspended solids floating on
the water or adhering to the sampling
device can be over-represented in the
water sample. Therefore, it is
important to see the actual amount of
suspended matter in the water column
prior to sampling. The TV camera can
be used to visually assess the actual
amount of suspended solids in the
well water at different depths
(Figure 4).
563
-------
Examining the Integrity of the Casing
A well with damaged casing may',
not fulfill its function of
assessing the true ground-water
conditions. In some cases, the well
is used for detection of
contaminants from'a subsurface
aquifer. For this, the well .is
installed so that the water entering
thewell comes only from the
aquifer. This is accomplished by
putting slots or screens only where
the well intersects the aquifer.
All other horizons are sealed.
(casing, grout, ,ben tonite,; >etc . ) .
If the casing is cracked (Figure 5).
or if there is a leaky seal between
joints of casing (Figure 4),
however, the ground water from
perched zones or from the surface
can enter the well and contaminate
the water. This may incorrectly
indicate that the aquifer is
contaminated. .
Damaged casing can also provide,
incorrect water level data. If one
wishes to .measure the hydraulic
gradient of a specific aquifer, the
wells must be open only to the. water
of the specific aquifer. Cracks or
holes in the casing may cause other
strata (not being tested) to affect
the level of the water in the well.
T.he camera can locate damages in the
casing.
Finally, if an obstructing
object falls into the well, the
camera can be used to determine what
may be needed to remove the object.
Examining the Screens and Slots
The purpose of screens and
slots, it to allow ground water to
freely enter the well and prevent
insitu sediment from coming in. The
slots or screens actually keep back
the gravel and/or sand in the
annular space of the well that was
installed to filter out the the soil
and rock part.icles , adjacent to..the
well. I Proper well development using
flushing techniques keeps the slots
free- of c logging ma tte.r , But-:how
free are the .slots? , The camera cafn
view, the s 1 o t:s (figure 6)-and
determine the .effectiveness of.
-------
impermeable strata. Water sometimes
comes in very slowly, a trickle or
just moisture on the side hole. At
other times the water comes in
quickly in streams. One would
expect the shape of the:stream to be-
laminar or sheet like, because,the
fractures or planes that permit its
entry are laminar and sheet like in
form. However, the shape of the
stream is usually pencil shaped
(Figure 8); water virtually squirts
into the hole. The direction of its
spray is always towards the center
of the borehole, no matter in what
direction the regional ground water
flows. The center of the borehole
is the point of lowest pressure.-
There may be a section of borehole
where one can see water flowing into
the borehole from different and even
opposite directions.
Below the water level one can
identify movement of ground water in
several ways. Water seldom will be
turbulent. Normally' the water
movement is almost imperceptable.
The movement can be observed by
watching suspended-sediment
particles moving in the flow of
water. Flow caused by secondary
permeability is easiest to see'
(Figure 9). A settling particle
passing a fracture or bedding plane
separation will be unaffected by it
if there is no flow. The particle
will be pushed away from the side
wall if water is flowing into the
hole. Or, the particle will be
sucked in towards the side wall if
water is flowing out of the hole.
Flow into the borehole from the pore
spaces of an aquifer is the most
difficult to see; particles will be
relatively more "active" than in
non-aquifer zones.
QUANTITATIVE ANALYSIS'.'
Contaminants in Suspension
Solid, s can be,, observed
suspended in the ground water of. a
borehole: or well. The actual
identification must be done by
sampling and laboratory.analysis. As
mentioned in a previous section of
the paper,' the spec if ic :gravity .of
t h'e suspended material can be
evaluated depending o'n whether it
floats or sinks. The texture of the
material would help to identify it.
Some materials observed are fibrous
(algal, growth)' or gelatinous (tar).
Color television would help to
further identify some of the
materials.
Immiscible Liquid Contaminants
One of the wells examined, by
the author was tested for the amount
of gasoline contamination. Gasoline
floats on water and has a different
index of r-effaction from water. The
camera >probe was lowered, into the
fluid column. It passed into- one
liquid and then into another. A
clearly defined miniscus was present
and-easily seen between the upper
(gasoline) and lower (water) fluid
layers. The volume of gasoline was
calculated by -using the value
measured by the television probe of
the thickness of the gasoline layer.
Measuring Flow Rates
To quantify flow rates, one
should recreate the visual image in a
laboratory with the sizes ,to proper
scale. The TV camera can be used in
the laboratory to verify the image.
The f 1 o w- o r di'scharge rat'es of
perched water and sa tur ated^-zone
water can. be. measured.in this
fashion. ,:-'•;:
565
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REFERENCES
Beyer, R. R. , and A. M.
Jacobs, 1986, Borehole TV for
the Problem Sites...A New
Investigative Tool,
Engineering and Mining
Journal, May 1986.
Recovery of the water level
during down-hole pump tests, could
also be observed with the camera.
One could also evaluate the effect
of perched water zones on the
recovery rate of the water level.
CONCLUSIONS
The use of borehole television
for the detection and assessment of
the contamination of ground water is
an important breakthrough in the
technology available to the
hazardous-waste management industry.
Current technology provides a black
and white, high-re solution image
from equipment that can be used in
most underground situations. The
addition of co1or-television
borehole probes, presently being
introduced, will make this technique
more valuable to this industry.
Disclaimer
The work described in this paper was not funded by the U.S. Environmental
Protection Agency. The contents do not necessarily reflect the views of the
Agency and no official endorsement should be inferred.
566
-------
FIGURE 1 - Borehole Camera with Lighted Attachments.
FIGURE 2 - TV Van
567
-------
FIGURE 3 - Down-hole View of Surface of Static Water Level.
FIGURE 4 - Suspended Solids Leaking into Well and Adhering to the Casing,
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568
-------
FIGURE 5 - Cracked Casing and Grouted Annular Space
FIGURE 6 - Slotted Casing (Underwater) as Seen in Elliptical Mirror at Upper
Right. •
569
-------
FIGURE 7 - Horizontal Fracture in. Bedrock-
FIGURE 8 - Pencil-shaped Streams of Water from Perched Aquifer
570
-------
FIGURE 9 - Sediment Mnvino in Flow of Water from Fracture at 323-ft Depth
571
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THE EFFECT OF pH ON 2,4-D BIODEGRADATION
G. L. Sinton, L. E. Erickson and L. T. Fan
Department of Chemical Engineering
Durland Hall
Kansas State University
Manhattan, Kansas 66506
ABSTRACT
Considerable uncertainty exists as to if and how 2,4-dichlorophenoxy-
acetic acid (2,4-D) inhibits microbial growth. The uncertainty may be
induced totally or partially by the observed inhibition effects of a
metabolic product 2,4-dichlorophenol (2,4-DCP). The results of experiments
with Pseudomonas sp. NCIB 9340 in one and two liter fermenters have shown
that culture pH is an important factor in determining the growth rate of
this microorganism and the extent of 2,4-DCP accumulation. Experiments with
1-liter batch fermenters over a pH range of 5.1 to 9.4 have shown that the
highest growth rates occur between pH 6.5 and 7.9; the specific growth rate
decreases as the pH is increased or decreased from this range until it
reaches zero at 9.4 or 5.1 respectively.
Extensive accumulation of 2,4-DCP occurred at a low pH; it was
accompanied by a reduction in the biodegradation rate, presumably due to
inhibitory effects of 2,4-DCP. 2,4-D biodegradation ceased completely when
the concentration of 2,4-DCP reached about 44 mg/L. No growth was observed
even after the 2,4-DCP concentration was reduced by non-biodegradation
mechanisms and new 2,4-D substrate was subsequently added to the culture.
Cultures exhibiting no growth for seven days at pH 5.1 could be revived to
resume normal growth by increasing the pH to 6.0.
INTRODUCTION
2,4-Dichlorophenoxyacetic acid
(2,4-D) is an aquatic and terrestrial
herbicide. It has been selected as a
model compound for study because of
its wide use and structural simi-
larity to other toxic and hazardous
compounds currently of interest, such
as other halogenated aromatic and
phenolic compounds. Furthermore,
2,4-D is among 38 compounds that the
EPA has proposed to add to a list of
chemicals used for identifying wastes
as hazardous and appropriate for
management under the Resource Con-
servation and Recovery Act (19).
Organisms capable of degrading
2,4-D were studied in pure and mixed
cultures mostly under aerobic condi-
tions (20) . A typical metabolic
pathway is illustrated in Fig. 1 (4).
Numerous investigations were under-
taken to develop kinetic models for
the biodegradation of 2,4-D and
573
-------
O.CHa.COOH
OH
OH
2.4-D
Cl Cl
2.4-dichlorophenol 3.5-dichlorocatechol
Cl .COOH
V COOH
- v
Cl
cis.cis-2.4-
dichloromuconic acid
N-.ci~
COOH
CH2
O
Cl
(acetate] -i- I
CH2
COOH
succinic
acid
COOH
COOH
Cl Jl .
To ?OOH
ky
chloromaleyl
acetic acid
4-carboxy methylene-
2-chlorb bu't-2-«nolide
Figure 1. Aerobic pathway for 2,4-D biodegradation (Cripps, R. E.,
and Roberts, T. R.) (4).
related compounds (2,10,14-17,22).
These studies have given rise to
various models, some of which appear
to yield conflicting results. Part
of the diversity among these models
can be attributed to the variability
of experimental conditions, such as
pH, temperature, aeration, supple-
mental nutrients, culture enrichment,
and substrate concentration range,
all of which have been found to
affect appreciably the rates of
biodegradation (20).
Many of the proposed biodegrada-
tion models do not account for in-
hibition effects (2,10,16,22). Most
of them are of the Monod type:
^ - WSl'^s
(1)
Specifically, e.g., Tyler and Finn
(22) have reported that this model
accurately describes growth on 2,4-D
up to 2000 mg/L and for 2,4-DCP up to
25 mg/L. Moreover, they have found
that 2,4-DCP inhibits growth at
concentrations above 25 mg/L.
Considerable uncertainty exists
as to if and how 2,4-D itself is
actually inhibitory. Some
researchers have reported inhibitory
effects of 2,4-D at various levels
such as 35 mg/L and 45 yg/g-soil
(14,17). Others (2,10,16,22) have
successfully employed versions of the
Monod model that neglect inhibitory
effects. The uncertainty may be
induced totally or partially by the
observed inhibition effects of a
metabolic product, e.g., 2,4-DCP.
Several researchers have found
2,4-DCP to be inhibitory at
relatively low concentrations
(3,12,22)
The Haldane model
y = (y rs])/([S] + K + ([S]2/K ))
ulcLX S J-
(2)
appears to be the most promising
model for the description of
inhibitory substrate degradation.
Numerous researchers have
successfully fitted this model to
their degradation data for 2,4-D. or
related compounds such as phenols or
574
-------
benzoate (6,14,18,21); nevertheless,
it does not appear to fit the data of
Tyler and Finn' (22) well.
PURPOSE
The primary goal of this
research is to examine the effects of
pH on the rate of 2,4-D biodegrada-
tion. The forms of 2,4-D biodegrada-
tion models and the values of their
kinetic parameters need be clarified
to understand the mechanism of 2,4-D
biodegradation under a variety of
conditions. An understanding of the
effects of pH is essential for the
design and evaluation of biological
treatment options to eliminate
production wastes and to manage bio-
degradation in field applications.
The pH should also be considered in
assessing environmental persistance
of 2,4-D and in determining if
undesirable metabolic products are
produced as a result of 2,4-D bio-
degradation.
APPROACH
Organism and Media
The organism used in the present
experiments was Pseudomonas sp. NCIB
9340. The growth media for this
organism contained the following:
1.5 g/L of K HPO,; 0.2 g/L of MgSO, .
7H 0; 0.05 g/L of CaSO, . 2H.O; 0.5
g/L of NH4NO_; 0.5 mg/L of FeSO, .
7H_0; de-ionized water; and either
2,4-D or 2,4-DCP as the sole source
of carbon. Cultures of the organism
were continuously maintained to
provide inocula throughout the
experiments by regular subculturing
in shake flasks with either 2,4-D or
2,4-DCP as the carbon source. The pH
and temperature of the maintenance
cultures were not controlled but
generally remained at levels of 6.5
to 6.9 and 22 to 25°C, respectively.
Assays
Substrate and product concentra-
tions were assayed by high perfor-
mance "liquid chromatography (HPLC); a
Varian MCH-10 column was employed
(monometric octadecasilane bonded to
silica). Detection was accomplished
by UV absorption at 283 nm. Acetoni-
trile and 0.015 N H SO served as
solvents in a gradient elution. This
HPLC procedure made it possible to
analyze aqueous samples directly
without any extraction or concentra-
tion. The only sample preparation
required was filtration through a 0.45
ym nitrocellulose filter to remove
the biomass. Biomass concentration
was monitored using a Bausch and Lomb
Spectronic 20 to measure absorbance
at 545 nm.
Batch Fermentations
Batch fermentations were con-
ducted in one and two liter fermen-
ters by controlling pH, temperature,
aeration, and stirring rate (tempera-
ture = 25 °C, aeration = 0.65 wm,
stirring rate = 700 rpm). These
controlled variables as well as the
concentrations of biomass, 2,4-D and
2,4-DCP were monitored. Experiments
were conducted over a pH range
between 5.1 and 9.4; the initial
concentration of 2,4-D was 200 mg/L.
PROBLEMS ENCOUNTERED
The determination of an
appropriate method of storage for
Pseudomonas sp. NCIB 9340 to provide
a consistent source of inocula was
the major difficulty encountered in
the present research. It has been
known that biodegradation rates of
2,4-D and other xenobiotic compounds
can be greatly increased by allowing
the organisms responsible for the
degradation to become acclimated to
the new substrates (1,10,13). Thus,
575
-------
it is desirable to have experiments
inoculated with organisms that are
equally acclimated to the test
substrate. In an attempt to provide
a supply of organisms with a uniform
history of acclimation, the original
freeze-dried sample of Pseudomanas
sp. NCIB 9340 was revived and grown
on 2,4-D. It was then dispensed into
a large number of test tubes contain-
ing the regular 2,4-D media, as
listed in the approach, plus 10
weight percent glycerol. Subsequent-
ly, these samples were placed in a
freezer at -10°C for long-term
storage. Unfortunately this method
of storage caused the organism to
loose its ability to degrade 2,4-D
and 2,4-DCP. Storage on refrigerated
agar slants was also attempted;
however, revival of 2,4-D degrading
organisms was generally not possible
after more than about two weeks and
was very inconsistent even over
shorter intervals.
The genes required for the bio-
degradation of xenobiotic materials
are often found on plasmids (5,7-9).
Based on the assumption that the
ability of Pseudomonas sp. NCIB 9340
to degrade 2,4-D was plasmid
mediated, Leslie (11) at the National
Collections of Industrial and Marine
Bacteria Ltd. investigated several
storage methods in response to our
inquiries concerning long term
storage of the organism. Pseudomonas
sp. NCIB 9340 plasmid DNA was well
maintained by regular subculturing on
2,4-D, and storage in liquid nitrogen
apparently maintained the plasmids,
but at a somewhat lower level.
Finally, in agreement with our
results, storage in 50% glycerol at
-20°C is unsuitable for plasmid
maintenance.
Because of the failure of the
glycerol and the agar slant methods,
regular subculturing was selected as
the procedure for culture mainte-
nance. It is generally observed that
after a certain period of acclimation
the organisms are not greatly
affected by further acclimation (10);
thus this method should provide
fairly consistent inocula.
RESULTS
The shake flask experiments gave
no indication of substrate inhibition
by 2,4-D in the concentration range
from 0.0 to 370 mg/L. In the 50.4,
94.5, 198, and 370 mg/L shake flask
experiments, accumulation of 2,4-DCP
was observed to reach levels of 0.1,
1.0, 13.2, and 16.9 mg/L, respec-
tively. The 2,4-DCP and 2,4-D were
eventually completely degraded. The
data from the flask initially con-
taining 2,4-D at 198 mg/L in Fig. 2
illustrate the basic pattern of the
substrate and product concentration
profiles obtained in the shake flask
experiments. The pH in these experi-
ments were not controlled; it
generally dropped from the initial
value of 6.8 to about 6.4 to 6.7 with
the largest drop occurring in the
flasks with the highest initial
concentration of 2,4<-D.
The results of experiments in
1-liter batch fermenters with 2,4-D
as the substrate indicate that
culture pH is a significant factor in
determining growth rates. Figure 3
demonstrates the relation between the
pH and specific growth rate. The
latter was obtained from the slope of
a logarithmic plot of the biomass
concentration against time during the
exponential growth phase. The
highest specific growth rates were
observed in the pH range from 6.5 to
7.9. The specific growth rate
decreased as the pH was increased up
to 9.4 where no growth or biodegrada-
tion was observed over a period of
four days. The specific growth rate
also decreased as the pH was reduced
from 7.0 to 5.1; at pH 5.1, no growth
576
-------
250.00
100.00
o.
'TIME, h
Figure,2. 2,, 4-D degradation by'Pseudomonas sp. NCIB 9340 in a shake flask
at 25 C .and.initial pH = 6,8; • , biomass concentration; * , 2,4-D concen-
tration; o , 2,4-DCP concentration.
i-t ' '
UJ
1—0.16-
1 •'-
00.12-
0
O
u_ •
"0.08-
UJ ,
Q_
CO
z:;
X
z:
sis *
, * 3K
*
•--....' ' ' - -.
SK . ' ' ' . •• , '
•. • • * .'••/:. . -
-•'•'• " • •
. sts
y 1 1 t t v
0 6.0 7.0 8.'0 9-0" 10
- . . - - PH •• ' '
Figure 3. Effect of pH on the maximum specific growth rate o'f Pse'udomohas
sp. NCIB 9340 growing on 2,4-D in batch fermenters at 25 C.1 ••'•'•
577
-------
was observed. Cultures exhibiting no
growth for seven days at pH 5.1 could
be revived to resume normal growth
and substrate consumption by
increasing the pH to 6.0.
Appreciable accumulation of
2,4-DCP was observed in batch fer-
mentation experiments conducted at pH
5.5 and 5.7. These were the two
lowest pH levels where growth was
observed. In both cases the
accumulation of 2,4-DCP appears to
have completely stopped the bio-
degradation of 2,4-D. In the pH 5.7
experiment, the 2,4-DCP concentra-
tion reached 49.5 mg/L with 2,4-D
biodegradation stopping at 38 mg/L.
No further growth or degradation was
observed even after the 2,4-DCP
concentration was decreased to below
20 mg/L and additional 2,4-D
substrate was supplied. The pH 5.5
experiment resulted in 2,4-DCP
accumulating to 44.5 mg/L with 2,4-D
biodegradation stopping at 84 mg/L as
shown in Fig. 4. The specific, growth
rates given in Fig. 3 for pH 5.5 and
250.00
00200.00
B
5.7 were based on growth, before
significant amounts of 2,4-DCP
accumulated. Accumulation of 2,4-DCP
is accompanied by a reduction in the
biodegradation rate, presumably due
to inhibitory effects of 2,4-DCP.
The results of experiments in 2-liter
batch fermenters with 2,4-DCP as the
only carbon source have indicated a
strong inhibitory effect . above
concentrations of 30 to 35 mg/L.
2,4-DCP accumulation does not
appear to be a factor in reduction
of the growth rate in the higher
range of pH (above pH 7),, but it
affects appreciably the growth rate
in the low pH range where it can
inhibit and possibly completely
arrest the degradation of 2,4-D. It
is not clear why 2,4-DCP accumulation
was observed at slightly higher
values of pH in the shake flasks;
this may be due to a difference in
vapor loss or other nonbiodegration
mechanisms compared to that observed
in the fermenters.
so. oo
°-0(o«o eH9e$o7o 4oTo eoTo §o7o"
TIME, h
Figure 4. 2.4-D degradation by Paeudomonas sp. NCIB 9340 in a 1-liter batch
fermenter at pH 5.5 and 25 C; * , 2,4-D concentration; o , 2,4-DCP concentration.
578
-------
CONCLUSIONS .
The shake flask and" batch
fermentation >. experiments gave no
indication of inhibition of growth by
2,4-D. Accumulation of 2,4-DCP was
observed in the shake flask experi-
ments but all of the 2,4-D and
2,4-DCP were completely eliminated
eventually. The Batch experiments
with 2,4-D indicated that pH is an
important factor in determining
growth rates. The highest growth
"rates were observed between pH 6.5
and 7.9. Accumulation of 2,4-DCP was
also dependent on pH; accumulation
^occurred at pH 5.5 and 5.7, the
lowest pH levels' where growth was
observed. In these two cases, the
accumulation of 2,4-DCP appears to
have stopped the biodegradation of
2,4-D, possibly killing the microbial
population. 2,4-DCP inhibits growth
above concentrations of about 30
ing/L.
ACKNOWLEDGEMENT
This work was conducted under
the sponsorship of the Engineering
Experiment Station (Office of
Hazardous Waste Research) of Kansas
State University.
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Relationship of Halogenated
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W.J., 1982, Kinetics of Bio-
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Parker, L.W., and Doxtater,
K.G., 1982, Kinetics ~ of '.
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Disclaimer ' "
The work described in this paper was not funded by the U.S. Environ-
mental Protection Agency. The contents do not necessarily reflect the views
of the Agency and no official endorsement should be inferred.
580
-------
NDEX
acid
wastes, 33
neutralization capacity, 34 ,
aery)ates, 23
Afri ca
mining wastes, 21
air' ' " • •
samp)ing of, 12
air stri pping, 42
ash
i ncinerator, 18
resi dual,3
assays
pH-stat, 23 .
ASW matr i x ,
concentrated, 20
attenuation, 33
Atterberg 1imits, 45
audi ts
waste minimization, 59
Australi a
mining wastes, 2f
bacter i al
treatment, 26
bari um, 57
Batch Reactor, 15
benton i te, 15
bioaccumu1 atioh, 56
bi oassays
jet fuel contamination, 14
plant responses to petrochemical Wastes, 24
biodegradation, 39
i n-s i tu, 25
1i gn in, 28
mi crobi al , 1.4
of 2,4-D, 62
P. chrysosporium, 28
soi1, 13
white rot fungus, 28
b i o1og i ca1
treatment, 41
b i pheny1s, 28
bo i1ers
i ndustr i al, 1
watertube, 21 ,
B.S procedure
penetrometry testing, 33
buffers
borate,23
calc i um .
a 1g i nate,23
si 1 icate matrix, 33
su1 fate, 56
• . $81 '.. '••-•'•
-------
Cambridge-Stereoscan, 57
Canada
mining wastes, 21
carbon
activated, 17
carbon dioxide
evolution, 14
carbonyl diimidazole, 23
Carl Zeiss-Jena TUR M-62, 57
eel 1
1ined, 16
cement, 3O
chemical
destruction, 43
China
electroplating wastes, 55
mining wastes, 21
chlor i de
acryloyl, 23
chlorine
contamination, 6
destruction, 43
organo- compounds, 3O
chromi urn
removal of, 8
waste recovery/reuse, 55
cl ay
soi1 1iners, 47
cleaning system
flue gas, 23
closure
cost, 52
coal
conversion residuals, 27
combustor
secondary, 6
compressive strength, 33, 34
conductivity
hydraulie, 33, 34
contaminat ion
groundwater, 11
hydrocarbon, 11, 14
soi1, 11, 14
Cracov, Poland, 11
creosote, 13
cultivars, 39
cutoff walIs
plastic/concrete, 19
cyan i de
destruction of, 41
waste, 33
oxidation of, 9
Daphnia, 13, 39
582
-------
5O
23
of the Environment (DOE), UK, 18
4
decontamination
electrical equipment, 36
Polychlorinated biphenyls
so i 1 , 7
transformers, 36
degradat i on
oily wastes,
proteolyt i c,
dens i ty
bulk, 12
Department
desorpt i on
thermal,
destruct i on
chemi ca1, 43
cyanide, 41
thermal, 31, 37, 39
Destruction Removal Efficiency
Detoxifier System, 54
d i ox i ns
waste incineration, 39
chlorinated, 43
di sposal
of solid hazardous waste, 29
d i st i 1 1 at i on
batch, 59
leachate, 38
process of, 41
solvent, 9
drainage front, 2O
dust
clay or kiln, 3O
fi1ter, 35
1 i me, 3O
econom i cs
evaIuat i on, 58
electrical equipment,
electrodes, 8
electronic capacitor
manufacture of, 59
electroplating plants,
sludges from, 55
electrostatic precipitator,
electro-kinetics
DC electrical field, 8
encapsu1 at i on
micro-, 23
surface, 33
entrapment, 33
gel, 23
enzymes
chymotryps i n;
cross 1 i nk i ng
stabi1 i zat i on
(PCBs), 36
(DRE) , 1
36
55
30
covalent attachment of;
of; crystaI 1i ne;
of, 23
583
-------
in field so i1s, 22
evaluat ion
capital project, 58
evaporat ion
process of, 38
extract i on
equi1i bri urn, 34
method of, 7
PCDD/PCDF, 43
sequential chemical, 34
treatment, 7
Federal Republic of Germany
mining wastes, 21
ferrous
phosphates, 56
f i re hazards, 11
fixation (see solidification)
metal, 3O
soluble silicates, 30
flexible membrane liners (FMLs)
polyethylene, 47
flow rates
di stri but i on
flue gas
samples, 1
flyash, 3O, 37
samples, 1
soli d i f i cat ion, 33
furans
chlorinated, 43
Furnace Bottom Ashes
gas
odours, 18
gasoline
contamination, 61
gel
stabi1izat ion, 30
glacial drift deposit, 11
glutaraldehyde, 23
grasses
bent-; brome-;
reed canary-,
gravity
of specific solids, 12
groundwater
contamination, 11, 14
movement, 61
grouting
i-njection, 30
Harwell, Waste Research Unit, UK, 33
hazardous wastes
management of, 12
treatment of, 9, 32
heat
recovery, 10
(FBAs), 18
dess i cat i on
39
of;
584
-------
33, 34, 45
1 1
27
54
homogen i zat i on
t i ssues of, 23
hydrau1i c
conduct i v i ty,
measures, E5
hydrocarbons
contami nat i on
aromatic, 25
polynuclear aromatics,
in-situ treatment of,
hysteresis, 20
immob i 1i zat i on
degradat i on, 50
incineration, 3
d i ox i n waste, 39
hazardous waste, 35
mobile system, 6O
oily siudge, 16
Polychlorinated Biphenyls (PCBs)
rotary k i1n, 16
siag, 5
i nc i nerator
liquid, 6
MWP-2000, 6
industrial wastes
d i sposa1,53
i norgan i c
acid wastes, 33
wastes, 33
irrigation (water), 3O
jet fuel
contamination, 14
Kuwait, Shuaiba Industrial
land treatment
oily wastes, 50
1andfarm fac i1 i t i es
Area (SIA), 16
16, 39
1andf i 1 Is
51
central low point, 52
design/operation, 52
gas odours, 18
hazardous wastes, 38
leachate test
dynami c, 34
leachates, 27
col 1ect i on, 42
di st i11 at i on, 38
reduction, 52
monitoring of, 46
organic halides, 46
synthesis of clay, 47
Total Organic Carbon (TOG), 46
treatment of, 15
585
-------
leaching, 3
characteristics of, 33
hydrauli c, 8
leaKs
identification, 52
contaminant, 61
least cost alternative, 23
1iners
clay, 47
Flexible Membrane Liners (FMLs), 47, 52
1inK system, 57
Low-Level Wastes (LLW)
treatment of, 3£
management
hazardous waste, 12
matri x
hydrated calcium silicate, 33
membranes
high pressure, 48
latex, 45
swel1i ng tests, 45
metals
bearing slags, 33
emission, 37
finishing industries, 33
hydrated ions, 30
polyvalent, 30
solidifi cat ion, 30
microbiology, 25
microtox test, 46
biodegradation, 13
migrat ion
i on i c, 8
minimization
wastes, 59
mining wastes
Africa; Australia; Canada;
China; Federal Republic of Germany;
legislation; Poland; research;
United Kingdom; USSR, 21
MODAR oxidation process, 10
nerve gas, 12
neutralizat ion •
of caustic/acid wastes, 33
new housing land, 51
Laboratory (ORNL), 32
(OWEP), 30
Oak Ridge National
oedometer, 8
Oily Waste Extraction Procedure
organics, 4O
free-phase, .20
gross (disappearance of), 15
particulate/semi-volatile, 1
polymer, 33
refractory, 15
586
-------
46
outf1ow
cl ay soi1s, 22
ox i dat i on
cyanide, 9
therma1, 58
oxygen
demand, 27
rate of uptake, 27
PCDD/PCDF, 43
penetrometry testing
BS procedure, 33
pesticides, 23
petrochemi cal
phytotoxicity, 39
wastes, 39, 24
PH
effects on 2, 4-D, 62
phase interactions
mass transfer, 2O
phosphate
ferrous, 56
Photobacterium phosphoratum,
phytotoxicity
petrochemical, 39
pi gments ,:,?. ? -
oxide, 56
pi 1ot seale, 41
plast i c .
siurry wal1s, 19
Poland
mining wastes, 21
remedial action, 11
pol1utants
enhanced movement of, 8
Polychlorinated Biphenyls (PCBs)
contamination of, 6, 26
decontamination of, 36 • .
metabol i sm of, 26 , r , ,' ,
polymerization (co-),23
Polytetraf1uoroethylene (PTFE), 18
Portland Cement, 33
post-closure, 52
Powdered Activated Carbon Treatment (PACT), 17
pozzolanic processes, 33 ,
preci pi tat ion, 41
Principle Organic Hazardous Constituent, (POHC) 1, 2
prototype test
hydrocarbon treatment, 54
Pseudomonas
biodegradation, 62
587
-------
58
55
1 1
Pulverised Fuel Ash (PFA), 18
pyrolysis
plasma arc, 2
qua Ii ty pred i ct i on
solidification process, 33
Q-150 OD Paulik-Erdey derivatograph,
rad i oact i ve
wastes, 12
Radioactive Mixed Wastes (RMW)
treatment of, 32
reactor
squelching batch, 27
recovery
heat, 10
secondary solvent,
waste chromium of,
recycling, 59
reduction
source, 58
remedial action
hydrocarbon contamination,
remedi at ion
soi1, 27
retarders, 3O
reuse
waste chromium of,
robotic technology,
rotary kiln
incineration, 4
Rotating Biological
Royal Arsenal
Woolwich, London,
Saint Vulbas, France
incinerator plant, 36
salt caverns
hazardous waste disposal, 29
repository, 29,53
salts
hardening, 57
scrubbing system
exhaust gas, 30
Shuaiba Industrial
si 1i cates
fixation of, 30
slags, 35
extraction, 5
incineration, 5
metal-bearing, 33
57
55
12
Contactor (RBC), 15
51
Area (SI A), Kuwait, 3O
fudges, 3O
alkylation, 39
and 1ime dust,
electroplat ing
farming of, 3O
homogenous, 3O
30
waste,
55
588
-------
14, 26, 31
Kuwa it, 16
oily, 16
supercritical fluid, 40
slurries, 3O
filter presses, 48
wal1s, 48
s1urry wal1
durabi1i ty of, 45
sodium hydroxide, 33
sodium hypochlorite, 33
so i 1 s
catalytic oxidation, 40
c1 ay, 22
contamination of, 11
decontamination, 7
fluid extraction, 40
humus content, 3O
remediation of, 27
solidification techniques
s i 1 i cate-based, 33
s i te-spec i f i c, 33
solidification technology, 33
cement-based;
hazardous wastes;
inorganic wastes;
long-term stability;
qual i ty control
sol ids (dry), 9
solvents, 59
di st i11 at i on of, 59
stab i1 i zat i on
gel, 30
steam str i pp i ng
process of, 41
st i11 bottom
trichlorophenol, 39
sulfates
calcium, 56
supercritical fluids
extraction of, 44
Superfund sites, 8
Stri ngfel low,15
New Lyme, 15
supernatant production, 33
telev i s i on
borehole, 61
Test & Evaluation Facility (T&E), 15
tests
freeze/thaw, 34
wet/dry, 34
Thames Barrier
London Flood Prevention, 51
Thamesmead, London, UK, 51
589
-------
thermal
desorpt ion, 4
destruction, 37, 39
oxidation, 58
vitrification, 31
thermoplastic processes, 33
toxicity test, 46
Toxicity Char. Leaching Proc. (TCLP), 9, 34
toxi cology
validation, 44
tracer breakthrough
clay soiIs, 22
transformers
decontamination of, 36
Transuranic Wastes (TRU)
treatment of, 3E
treatment
bi ologi cal, 27, 41
extraction, 7
hazardous wastes, 9, 32
in-situ, 54
leachates, 15
low-level wastes, 32
radioactive mixed wastes, 32
removal of volatile hydrocarbons, 54
Transuranic wastes, 32
wastes, 32
Treatment, Storage, Disposal Facil's (TSDF's)
tri chlorophenol
st i11 bottom, 39
UK Department of the Environment (DOE), 33
United Chrome Products, Inc., 8
United Kingdom
mining wastes, 21
Thamesmead, London, 51
USSR , •
mining wastes, 21 . <
Utica Gas & Electric Co., 27
Vapour Phase Adsorption (VPA), 42
Vapour Phase GAG Adsorption, 42
vermi cu1 i te, 39
v i trifi cat ion
i n-s i tu, 31
vitrification processes, 33
Waste Research Unit Odour Index (WRUOI), 18
wastes
ac i d,33
caustic solution, 33
decomposition, 18
destruction, 2
dewatering, 16, 30
hazardous, 5, 38
590
-------
hazardous generation, 35
hazardous incineration, 35
hazardous liquids, 1
inorganic, 33
inorganic acid, 33
1 i qu id cyan i de, 33
minimization of, 59
mi ning, 21
muni ci pal soli d
oily degradation, 50
petrochemical, 24, 39
radioactive, 12
reduction of, 59
repos i tory, 53
sol id cyan ide, 33
wastewater, 17, 34, 55
water
content of, 34
weather resistance, 34
we) I
inspection, 61
wood preservation, 13
zero-migration, 29, 53
The editor of these Proceedings wishes' to tender special thanks to:
Daniel W. Farrell, Adam Dolby, Jacqueline Lewis, and Ellis Chu.
591
•h U.S. GOVERNMENT PRINTING OFFICE: 1987—7 48 -121 / 6 7 0 2
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