United States
                    Environmental Protection
                    Agency
Hazardous Waste Engineering      ~* &
Research Laboratory                / | \
Cincinnati OH 45268
                    Research and Development
EPA/600/S2-85/091 Dec. 1 985
c/EPA          Project  Summary
                   Study  of  Codisposed
                   Municipal  and
                   Treated/Untreated  Industrial
                   Wastes

                   Larry W. Jones, Tommy E. Meyers, and Robert J. Larson
                                  54
                     A study was undertaken to deter-
                    mine  the long-term effects of codis-
                    posal of industrial waste (IW) and mu-
                    nicipal solid wastes (MSW) under
                    controlled, simulated landfill condi-
                    tions. Three IW's (treated or untreated
                    by solidification) were disposed with
                    MSW in nine specially designed test
                    cells at an approximate volume ratio of
                    1:4. The sealed test cells were leached
                    with distilled water at a rate of 1.27 cm
                    per week. Leachate was collected
                    anaerobically and  analyzed for 28
                    parameters monthly or quarterly over a
                    4-year period. The three IW's were an
                    electroplating waste (EPW), a  chlorine
                    production brine (CPB), and a glass-
                    electronics etching sludge (GES). Two
                    processes were used for solidification
                    of the wastes: one added cement plus
                    a patented ingredient to waste, and
                    the other mixed waste with lime and
                    flyash.
                     In all cases, the codisposal of treated
                    or untreated IW and MSW had signifi-
                    cant  effects on the nature of the
                    leachate produced. All IW's increased
                    the pH of the leachates from about 5.3
                    to 6.3, which alone could affect compo-
                    nent  solubilities  and  biological activi-
                    ties of the MSW. The GES inhibited bio-
                    logical  activity  in the MSW to the
                    greatest extent, and the EPW inhibited
                    it less. The CPB had little or no effect on
                    the MSW biological activity. Both pre-
                    treatment  systems greatly decreased
                    the apparent effects of IW on  the bio-
                    logical activity in the MSW.
                     Heavy metals  in the untreated and
                    treated IW's generally did not appear in
the MSW leachates in appreciable
amounts. However, heavy metal con-
centrations were generally increasing
in the leachates during the last year of
the study.
  IW's containing soluble salts (CPB,
for example) are  not good candidates
for disposal with MSW, even after pre-
treatment. Levels of salts from CPB test
cells were high and consistent over the
entire study period, even when the CPB
was pretreated.
  Interaction of leachates with a 31-cm
layer of soil at the bottom of the test
cells  produced only minor modifica-
tions in leachate quality. However, in-
teraction of soil and leachate can in-
crease rather than reduce the pollution
potential of the leachate.
  This Project Summary was devel-
oped by EPA's Hazardous Waste Engi-
neering Research Laboratory, Cincin-
nati, OH, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).

Introduction
  Disposal of industrial wastes (IW's)
has become increasingly expensive and
difficult because of heightened public
awareness and regulatory restrictions.
In the past, nearly all types of wastes
were indiscrimirtantly disposed of at lo-
cal dump sites. Increasing interest and
progress in  landfilling technology
quickly followed U.S. Environmental
Protection Agency (EPA) bans on burn-
ing at dumpsites.  Landfilling is now the

-------
recommended  and nearly universal
method of disposal for municipal solid
wastes  (MSW), and IW's have  been
delegated  to  secure  landfills  or
incineration.
  Though disposing of hazardous  IW
along with MSW in dumps and landfills
was a common U.S.  practice until a few
years ago, little information is available
in this country on the environmental ef-
fects  of this practice. Codisposal with
MSW is the  recommended practice  for
many hazardous  wastes in Great
Britain,  where  researchers claim that
the scientifically determined disposal of
hazardous wastes with MSW can be an
acceptable and even preferred manage-
ment alternative for  many  toxic
substances.
  This study addresses the effects of IW
and  MSW codisposal in a simulated
MSW landfill environment. Eleven large
(181-cm-diameter) test cells were f'lled
with MSW only or with MSW plus one
of three IW's—an electroplating  waste
(EPW),  a  chlorine  production  brine
(CPB), and a glass-electronics etching
sludge (GES). Two  additional smaller
cells were also filled with  MSW only. All
wastes were collected from actual  in-
dustrial waste streams.
  A secondary goal of the study was to
investigate the possible use of chemical
solidification/stabilization  of the  IW to
reduce contaminant loss  in the  codis-
posed wastes. Two commercially avail-
able methods were used for this
process.
  This report describes the overall  re-
sults of the leaching data from all three
IW's, treated and untreated, for leachate
samples collected above  and  below a
31-cm soil layer over the complete four-
year (1510-day) study period.

Materials  and Methods
  The three IW's, treated or untreated,
were codisposed with  MSW in nine
large (9.65 m3 total volume), especially
designed test cells. MSW and treated or
untreated IW were loaded m the test cells
in a ratio of approximately 4.1 by volume.
The  sealed test cells were leached with
distilled water at a rate of 1.27 cm  per
week. The leachate was collected anaer-
obically and analyzed for 28 parameters
monthly or quarterly over the four-year
study period.
  Four test cells loaded with MSW only
were also included in the study as con-
trols. Of these cells, two  were smaller
and  had half the  height and diameter
(i.e., 1/8th the volume) of the large cells.
Selected Wastes
  The three IW's included in this study
(EPW, CPB, and GES) are largely inor-
ganic, have high levels of toxic  heavy
metals and/or  soluble inorganic salts,
and are produced in large quantities in
the United States. They are considered
to be some of the most difficult to con-
tain and are at the root of many environ-
mental problems.
  The MSW used in this study was pro-
vided by the Sanitation Department of
the City of Vicksburg,  Mississippi, and
by two private haulers operating in War-
ren County, Mississippi. Residential col-
lection routes were selected to exclude
any commercial, industrial, or hospital
wastes.

Test Cell Design
   The test cells were designed to simu-
late a  1.83-m-diameter core through a
typical landfill  in which IW and MSW
might be codisposed. The cells were de-
signed so that deionzied leaching water
of known composition and pH could be
added in premeasured  amounts
through the top of the otherwise  sealed
cells and the resulting leachates could
be sampled above and below a  31-cm
soil layer. The test cells were free-
standing, rolled steel cylinders housed
in a large-scale facility that maintained a
temperature of 25  ± 3°C year-around.
All interior cell surfaces were coated
with an  acid-base  resistant coal tar
epoxy to protect the walls from  corro-
sion or leaching. As mentioned, 11 of
the units were  large (1.83 m internal di-
ameter by 3.66 m high), and two were
small (0.91 m inside diameter by  1.93 m
high).  The small cells were filled with
MSW only and were used to evaluate
the effects of test cell size on leachate
quality. All cells contained polyethylene
beads  in the leachate storage space on
the bottom to provide support  of the
soil  layer and pore space storage  for
leachate.

Test Cell Loading
   Two large and two  small cells were
loaded with MSW only. The  remaining
nine cells were loaded with two layers
of treated or untreated IW interspersed
between three layers of MSW. The
MSW was placed in 30.5-cm lifts that
were compacted to 400 to 415 kg/m3 wet
density  with a 2315-kg  lead weight.
Each layer of chemically treated IW was
made  up of four  cylindrical, 61-cm-
diameter cores of solidified/stabilized
waste  product. MSW was also packed
around the treated IW cores and com-
pacted to approximately the same wet
density by use of a hand-held tamper.
This loading yields an MSW-to-IW vol-
ume ratio of approximately 4 to 1, which
is in the range  recommended for
codisposal.

Leachate Collection and Pro-
cessing
  Leachate samples were handled with
care to preserve their anaerobic nature
during sampling and before  preserva-
tion. Quarterly leachate samples were
drawn by suction from the test cells
through Tygon*  tubing  into  a 500-ml
stoppered  glass aspirator bottle
mounted on the  glovebox.  Leachate
was then forced  inside the glovebox
with He  pressure. The  glovebox  had
previously been purged with He for at
least 5 minutes.  The smaller  monthly
samples were prepared within the
glovebox without contacting atmo-
spheric air. They could be subsampled
and  preserved quickly enough to make
the  He atmosphere  unnecessary.
Parameters measured included the fol-
lowing:*
  Specific conductance     B
  Alkalinity                Be
  Cl                      Cd
  TKN                    Cr
  TP
  TOC
  Ca
  Fe
  K
  Mg
  Mn
  Na
  Al
  As
Cu
Hg
Ni
PB
Se
Zn
BOD5
COD
TVA
pH
F
*TKN = Total Kjeldahl Nitrogen;  TP
  =  Total  Phosphate;  TOC = Total
  Organic Compound;  BOD5 = Bio-
  chemical Oxygen Demand;  COD =
  Chemical Oxygen  Demand; TVA =
  Total Volatile Acids.

Conclusions

Leachates from Cells Contain-
ing MSW Only
  Leachates from the test cells contain-
ing only MSW were typical of those re-
"Mention of tradenames or commercial products
 does not imply endorsement or recommendation
 for use.

-------
ported in the literature. Initial leachates
have very high  organic  loadings,
slightly acidic pH (around 5.3), and sig-
nificant ionic loadings. Early samples
exceeded drinking water standards for
all constituents with an established
standard except Cu. Throughout the
study,  Fe and Mn concentrations aver-
aged 1000 and  100 times the drinking
water standard,  respectively. As, Cr, Se,
Zn, and Cl also exceeded  these stan-
dards in their average concentrations in
the leachate.
  Levels of constituents varied greatly
in the leachates  from the four cells con-
taining MSW only. This variability set
the lower limit for detecting the effects
of adding IW's to the  MSW.
  Levels of constituents varied greatly
in the leachates from  the four test cells
containing MSW only.  This variability
set the lower limit for detecting the ef-
fects of adding IW's to the MSW.
  The two small control cells, contain-
ing only 1/8 the volume of the larger
ones,  received twice the volume of
leachate per kg  of dry MSW. Compari-
son of these  results with those of the
larger  control cells indicated that the
loss of many metals and the oxygen de-
mand were proportional to the amount
of leachate produced and largely inde-
pendent of the  amount of waste or its
configuration. However, losses of the
highly soluble constituents such as Na
and Cl were more nearly proportional to
the amount of MSW loaded into the test
cell than to the  volume of the leachate
produced.

Leachates from Cells Contain-
ing Codisposed IW and MSW
  In all cases, the codisposal of treated
or untreated IW with  MSW had signifi-
cant effects  on the  character of the
leachates produced.

Organic Parameters

Untreated IW's Disposed  with
MSW
  Inclusion of any of the untreated IW's
increased leachate pH from about 5.3 to
about 6.3, which  alone would be ex-
pected to affect  component solubilities
and  biological activities. The  GES ap-
peared to inhibit MSW biological activ-
ity to the greatest extent. Cells contain-
ing untreated GES had leachates with
lower COD and BOD (both  averaged
only 28% of the values for MSW-only
leachates), lower TOC (29% of MSW-
only values),  and lower TVA (34% of
MSW-only values). The untreated EPW
had a smaller inhibitory effect, on these
parameters, averaging  50% to  75% of
their values in the MSW-only leachates.
The untreated CPB had little or no effect
on these parameters; however, it did
produce a small pH change. The inhibi-
tion  appears  to be the  result of minor
components such as toxic metals rather
than high soluble salt levels or high pH.

Treated IW's Disposed with
MSW
  Test  cells containing solidified IW's
and  MSW produced leachates with pH
values  and organic parameters similar
to the MSW-only leachates. Thus, both
processes appeared to overcome the in-
hibitory effects of the IW's on the micro-
biological processes in the MSW.

Heavy Metals
  Heavy metals  in the IW's were not
readily leached out of the test cells. The
EPW, for  example, contained the
highest levels of the heavy metals—6%
Cr, 10% Cu, and 0.3% Ni. This untreated
waste produced  leachates  with signifi-
cantly increased  levels of these metals,
but the increases were very small com-
pared with the total metals added to the
cells. Test cells with MSW and treated
EPW did produce significantly  higher
leachate levels of Ni but not of Cr or Cu.
Test  cells with MSW plus treated or un-
treated CPB or GES produced leachates
without significantly higher or lower
metal levels,  since neither waste con-
tained  appreciable amounts of heavy
metals.
  The codisposal of MSW and IW's con-
taining high levels of heavy metals in
hydroxide sludges may be an environ-
mentally acceptable option  since the
added metals were  not found in large
quantities in the MSW-IW leachates.
Note, however, that the metal levels in
these leachates were slowly increasing
in the last year of the study, and their
levels could increase appreciably over
time. Also, the added IW appears to in-
hibit or modify the microbial activity in
the MSW mass; thus long-term results
cannot be predicted without knowledge
of how metal ions affect MSW microbial
stabilization.

Soluble Salts
  Soluble salts in the IW's were imme-
diately  apparent in the leachates from
those test  cells. The cell containing
MSW plus untreated CPB produced
leachates with extremely high Na and Cl
concentrations, even after four years.
Solidification  of the CPB did reduce the
initial concentrations, but their losses
were still high and consistent through-
out the study. Na  and Cl were also
found at consistently higher levels  in
leachates from test cells containing
both treated  and untreated  EPW and
GES,  but these  concentrations were
only two to three times those of MSW-
only leachates. The codisposal of MSW
and IW's with high levels of  soluble
salts, therefore, appears to be environ-
mentally unsafe  because of the rapid
and large losses  of salts to leaching
waters even  after pretreatment with
solidification.

Calcium and Magnesium
  The divalent cations Ca  and Mg were
prevalent in all leachates,  including the
controls. The  presence of treated or
untreated IW increased their concentra-
tions by 100% to 200%. Ca was  a major
component  in all the IW's and was
found near its solubility limit in all IW
leachates.

Iron
  Fe levels in the leachates are probably
indicators of the overall microbial activ-
ity in the waste mass. Addition of any of
the untreated IW's to MSW consistently
lowered  the  Fe concentration in the
leachates produced,  most  likely be-
cause  of inhibition  of the  microbial
activity in the test cells.

Interaction of Leachates with
the Soil Layer
  Interaction of leachates from test cells
with a 31 -cm layer of a clayey-sandy soil
produced only minor modifications  in
leachate  quality. Most  constituents
were not affected by passage  through
this layer, but As and TP were signifi-
cantly  removed.  Al,  Cd, and Hg were
added to the  leachates from  the soil in
significant amounts. The  interaction  of
MSW leachates with underlying soils
requires  more study. Apparently, the
soil cannot simply be considered as an
absorber of materials from the passing
leachate.  Leachates  can  interact with
the soil and remove selected soil con-
stituents, thereby increasing rather than
reducing the overall pollution potential
of the leachate.
  The full report was submitted  in fulfill-
ment of Interagency Agreement No. D4-
0569 by the  U.S. Army Waterways Ex-
periment Station under the sponsorship
of the U.S.  Environmental Protection
Agency.

-------
     Larry W. Jones, Tommy E. Myers, and Robert J  Larson are with  U.S. Army
      Engineer Waterways Experiment Station, Vicksburg, MS 39180.
     Robert E. Landreth is the EPA Project Officer (see below).
     The complete report, entitled "Study of  Codisposed Municipal and Treated/
      Untreated Industrial Wastes," (Order No. PB 85-235 588/AS; Cost: $20.50,
      subject to change) will be available only from:
            National Technical Information Service
            5285 Port Royal Road
            Springfield,  V'A 22161
            Telephone: 703-487-4650
     The EPA Project Officer can be contacted at:
            Hazardous Waste Engineering  Research Laboratory
            U.S.  Environmental Protection Agency
            Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
     BULK RATE
POSTAGE & FEES PAI
        EPA
   PERMIT No. G-35
Official Business
Penalty for Private Use $300
EPA/600/S2-85/091

-------