EPA/540/2-89/037
     SUPERFUNDTREATABILITY
            CLEARINGHOUSE
               Document Reference:
 VeriTec Corp. Case Study, Hazardous Waste Management Utilizing Lime. Paper
presented at the Annual Meeting of the National Lime Association, Phoenix, Arizona.
                   13pp. AprM9,1987.
              EPA LIBRARY NUMBER:

           Superfund Treatabllity Clearinghouse - FAAP
                               U.S. Environmental Protection Agency
                               Region 5, Library (PL-I0'}
                               77 West Jackson Bci,:!"/:.;/  ''  ~~oi
                               Chicago, IL 60604-35,0

-------
                SUPERFUND TREATABILITY CLEARINGHOUSE ABSTRACT
Treatment Process:

Media:

Document Reference:
Document Type:

Contact:
Site Name:
Location of Test:
Immobilization - Flyash Solidification

Sludge/Metal Finishing

VeriTec Corp.  Case Study, Hazardous Waste
Management Utilizing Lime.  Paper presented at the
Annual Meeting of the National Lime Association,
Phoenix, Arizona.  13 pp.   April 9, 1987.

Conference Paper

Andre DuPont
National Lime Association
3601 North Fairfax Drive
Arlington, VA  22201
703-243-LIME

VeriTec Corp. (Non-NPL)

Knoxville, TN
BACKGROUND;  This report presents the results of treating a plating sludge
having high levels of Cu, Ni and Cr with a lime fly ash additive.  The
pozzolonic reaction solidified the sludge.  The results of various leaching
tests are presented and discussed.  An economic analysis suggests that  the
mixture used was more cost effective than other types of solidifying agents
and processes.  Various additive sludge ratios are recommended and a con-
ceptual system design along with costs is presented.
OPERATIONAL INFORMATION;  The sludge that was investigated was a Cu-Ni-Cr
hydroxide sludge from alkaline pH precipitation of a plating-rinse waste-
water.  The untreated sludge contains 35 g/kg of Cu, 65g/kg Ni and 72 g/kg
of Cr.  Sludge density is 1.133 g/cc.  Lab tests revealed that solidifica-
tion was feasible and that the solidified samples displayed considerable
unconfined compressive strength.  The structural strength was reported  to
be between 100-125 psi.  Lab tests were followed with field tests to deter-
mine the effect of leaching on the solid samples.  At 21 days treated
samples were subject to the EPA-RCRA EP toxicity procedures, deionized
water leaching procedures, and the Multiple Extraction Procedure (MEP)
leaching test.  Detailed explanation of the leaching procedures are given
along with methods of analysis used to determine heavy metal concentra-
tions.  No QA/QC information is contained in the report.
PERFORMANCE:  Laboratory simulation studies revealed that the fixation
process could reduce the EP toxicity.  EP toxicity tests for Cr, Ni and Cu
with initial concentrations of 73.0, 65.6 and 22.0 mg/1, respectively, were
reduced by treatment to 2.9, 1.0 and 1.0 mg/1, respectively.  Field tests
reveal that levels of Ni, Cr and Cu can all be reduced by the fixation
process.  The following tables show results from the various leaching
tests.  Cyanide (CN) is not used in the plant, however, CN was found at
0.13 and 0.05 ppm in the raw sludge leachate samples. CN was <0.01 in all
treated sludge samples showing this fixation process also retards low level
3/89-30                                              Document Number:  FAAP

   NOTE:  Quality assurance of data nay not be appropriate for all uses.

-------
leaching of cyanides.  Total chromium was reduced from 22 to .02 - .05 ppm
in one set of samples and from 3.5 ppm to 0.4 - 0.1 ppm in another set of
samples.  Nickel was reduced from 87 to 0.01 ppm with treatment.  The
authors state that they believe the wastes no longer violate hazardous
waste criteria and recommend that the treated wastes be delisted.
    An economic analysis of the costs associated with fixing one ton of
sludge using a 1:1 mass ratio of fixing agent and sludge was conducted.
Pozzolonic process is the cheapest of those evaluated.  Cement costs $70
per ton whereas pozzolonic costs as low as $12.50 per ton depending on the
type of fly ash used (bulk or bagged).  Total disposal costs increase as
the mass ratio of fixing agent to dry weight sludge increases.  The authors
provide a conceptual design of a process along with estimated costs to
construct a one ton per day system.  Total system capital/construction
costs are estimated to be $65,000.

CONTAMINANTS;

Analytical data is provided in the treatability study report.  The
breakdown of the contaminants by treatability group is:

Treatability Group             CAS Number        Contaminants

WlO-Nonvolatile Metals         7440-47-3         Chromium
                               7440-02-0         Nickel

Wll-Volatile Metals            7440-43-9         Cadmium

W12-0ther Inorganics           57-12-5           Cyanide
                                   TABLE 1

           LEACHING STUDIES OF RAW AND LFA FIXATED (2:1) CYLINDERS


       Untreated	Treated               Untreated    Treated

       EPA - RCRA    EPA - RCRA             D.I. H20     D.I. H20

Cr       73.0*         2.9                    0.63        <0.01
Ni       65.6          1.0                    0.61         0.04
Cu       22.0          1.0                    0.24         0.07
3/89-30                                              Document Number:  FAAP
   NOTE:  Quality assurance of data may not be appropriate for all uses.

-------
                                  TABLE 2
        EPA-RCRA LEACH TESTING OF LFA TREATED AND UNTREATED SLUDGES
Metals
Untreated
 Treated
Arsenic
Barium
Cadmium
Chromium
Lead
Mercury
Selenium
Nickel
Copper
<0.001*
0.23
<0.001
7.4
<0.01
<0.001
<0.001
3.9
2.4
<0.001
0.09
<0.001
0.81
<0.01
<0.001
0.002
4.8
0.02
                                  TABLE 3

                      PLATING SLUDGE LEACHATE LEVELS
                                (mg/liter)
                            CNJ
            Cd
Ni
*A11 value* in Bg/1 of leachate.
 CN - Cyanide
Cr
Raw Unreacted
Fixated #1

Fixated #2

Raw Unreacted
Fixated #3

Fixated #4

0.13
<0.01
<0.01
<0.01
<0.01
0.05
<0.01
<0.01
<0.01
<0.01
0.001
0.004
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
87.0
<0.01
<0.01
<0.01
<0.01
76.0
0.15
<0.01
<0.01
<0.01
22.0
0.03
0.02
0.05
0.05
3.5
0.10
0.04
0.07
0.07
Note:  This is a partial listing of data.
       information.
              Refer to the document for more
3/89-30                                              Document Number:  FAAP

   NOTE:  Quality assurance of data ay not be appropriate for all uses.

-------
                                   -lfr- f")
               CASE STUDY

HAZARDOUS WASTE MANAGEMENT UTILIZING LIME



       National Lime Association

              April 9, 1987



             Annual Meeting

            Phoenix, Arizona
      Dennis W.  Weeter,  Ph.D.,  P.E.
          Larry  W.  Jones,  Ph.D.
           VeriTec  Corporation
              P.O.  Box 8791
           Knoxville,  TN 37996

-------
EXECUTIVE SUMMARY

     A plating sludge with high  levels  of  Cu, Ni, and Cr was
treated with a lime-fly ash. additive.   A pozzolonic reaction
between the additive and the plating  sludge brought about a 21-day
structural strength of 100-125 psi.   The solidified product was
tested with EPA-RCRA, extractant procedure (EP) toxicity test;
deionized water leaching; and the multiple extractant procedure
(MEP).  Chromium levels were significantly below RCRA standards;
copper and nickel leachates levels were reduced by solidification.
Based upon these results the waste was  delisted by EPA.

     Economic analysis indicates that the  lime and fly ash
admixture is more cost effective than other .agents studied
(Portland cement, lime, or sodium silicate).  The lime-fly ash
admixture is recommended as the treatment  reagent of choice at a
3:1 or 4:1 reagent to sludge ratio (W/V).  A system process, a
recommended design, and a bid scenario  are presented in this
report.  Projected capital costs and construction costs are about
$50,000 and total project costs are estimated to be $65,000.


BACKGROUND

     This company generates a Cu-Ni-Cr  hydroxide sludge from
alkaline pH precipitation of a plating-rinse, wastewater.  These
metals are plated on plastic predominantly for automobile parts and
consumer products.  Table 1 presents data  on the existing sludge
mass and its characteristics.

     The sludge is thickened by sedimentation to about 1% solids by
weight and then pumped to a 1500 gallon holding tank where it
further thickens to 2-3% solids by weight.  The sludge is then
pumped through a Shriver filter press and  thickened to 28% solids
by weight.  The 28% solids sludge is the topic of the study.  The
filter press filtrate is recycled to the start of the treatment
works.
Table 1.  Raw Sludge Composition
Moisture Content
Cr
Cu
Ni
Mass Produced
Mass Produced
72%
72 g/Kg - wet weight basis
35 g/Kg - wet weight basis
65 g/Kg - wet weight basis
10 cu. yd/month
23 cu. yd/month
  (at maximum plating capacity)
Sludge Density
1900 Ib/cu.  yd or  1.133  g/cc

-------
 RESULTS AND DISCUSSION

      These studies were broken into five phases:  1.  lab-scale
 tests were conducted with several agents to see if stabilization/
 solidification was a possible alternative; 2.  a field-level test
 was run with the most economic stabilization reagent; 3.  a series
 cf lab simulations were conducted in order to evaluate optimal
 nxes of the chosen agent and to evaluate leaching potential and
 hazardous characteristics; 4.  multiple field level, in plant
 tests, were conducted to evaluate process variability; and 5.  the
 resultant sludges were evaluated by the multiple extraction
 procedure (MEP).

      Lab-scale Tests:  Samples of filtered sludge were collected,
 and grated by hand so it would pass through a 40 mesh sieve.   Then
 predetermined amounts (percent by weight) of several stabilization
 reagents were blended with the grated waste.  The final mixtures
 were then compacted by the Modified Proctor Test in several 3 inch
 long by 1 inch diameter molds.  When the samples were removed from
 the molds,  one duplicate was wrapped in cellophane while the  others
 were left to air dry.  Stabilization reagents tested were Portland
 cement,  sodium silicate, Calcilox (Dravo trademark),  lime,  and lime
 plus fly ash (LFA).   Samples were tested for 7  and 14 days
 unconfined compressive strength (UCS).
                                                            

      The unwrapped,  air dried, cylinders retained zero UCS.   For
 optimum strength,  moisture must be available for the  slow LFA
 pozzolonic  reactions.  The percent of  moisture  is a  critical  factor
 in strength development.

      The wrapped cylinders demonstrated appreciable  UCS  gain.   In a
 comparison  of  cylinders prepared  with  different  reagents  at the
 weight-ratio of  1:1  (stabilization reagent  to dry weight  of the
 sludge),  cement  showed UCS values of greater  than 200 psi;  Calcilcx
 ash UCS  values near  100, and LFA  was between  50-100  psi.  Neither
 lime  nor sodium  silicate by  themselves  showed strength gain in
 these  tests.   Sodium silicate in  combination with  other  agents
 (LFA,  cement,  calcilox)  did  not add  nor reduce UCS.   Calcilox
 blended  with LFA increased (3-5 times)  the  strength developed by
 LFA alone.

      Following these  studies,  an  economic evaluation  was conducted
 to determine the best stabilization  reagent.  LFA can either be
 prepared by  blending  CaO and  fly  ash, or  by purchasing a baghouse
 waste  product  produced at  most  chemical-lime kiln operations.  This
 material  is  generally about  40% CaO, 40%  fly ash, and 20% CaC03.

     Calcilox  is also a  large  volume, prepared waste  material.   It
was decided  to conduct  further  tests using LFA alone  and LFA with
 small  amounts  of Calcilox.
FIELD TESTS

     Several barrels of LFA were shipped to the plant for testing,
An air compressor line was placed in the bottom of a 1500 gallon

-------
 sludge storage tank, which was used as a mixing tank.

      A 45:55 mixture of LFA to plating sludge (dry weight) was
 produced by adding approximately 250 pounds LFA to the tank.   The
 mixture was pumped through the filter press and dewatered.  The
 sludge press, which dewatered raw plating sludge to about 20%
 solids by weight,  produced a mixture of LFA and sludge which was
 about 40% solids by weight.   Due to improved dewaterability,  no
 volume gain was seen in the 1:1 LFA-sludge formulations.   However,
 a higher dewatered density (about 1.23 g/cc) resulted since the LFA
 (90 Ib/cu.  ft.) displaced some of the water (62.4 Ib/cu.  ft.).

      During the filter  run,  the composite, liquid filtrate was
 sampled and analyzed for heavy metals (Table 2).   The filtrate  was
 returned to the wastewater treatment system where it is diluted to
 about 1 to  60 based upon raw wastewater flows.   The effect of the
 LFA addition on filtrate water quality is negligible.


          Table 2.   LFA-Sludge Liquid Filtrate  Analysis
                  (all values in mg/1,  except pH)
Arsenic
Barium
Cadmium
Chromium
Copper
< 0.003
0.09
< 0.001
0.79
1.12
Lead
Nickel
Selenium
Silver
PH
0.13 *
0.47
0.015
< 0.002
11.0
      Samples of  raw sludge and LFA-treated  sludge were taken to the
laboratory where duplicate samples were wrapped or  left to air dry.
The  air  dried samples again failed to develop  appreciable
structural strength.  Wrapped LFA-sludge  samples were tested for
UCS  at day 3 (20 psi), day 5 (25 psi), day  7  (40 psi) and day 12
(50  psi).

      At  day 21 treated and untreated, wrapped  samples were
subjected to leaching tests for 24 hours  using the  EPA-RCRA
acetic-acid leaching procedures.  Table 3 presents  the results from
this  study.  First, the raw sludge would  probably violate toxicity
standards since the Cr concentration is greater than 5.0 (100 times
the drinking water standard).  Leachates  from  the treated samples
had a Cr value of 0.81 mg/1.  It should be  emphasized that no
dilution effects (less total sludge in treated samples)  have
occurred since each sample had the same percentage  (20%)  of plating
sludge.  The treated sample had an extra  20% of LFA but  less
liquid.  It is also important that the treated sample did not
contribute excessive concentrations of fly-ash-related metals.
Metals normally associated with fly ash include selenium,  barium
,  and selenium  Csee Electric Power Research Institute,  Coal Ash
Disposal Manual (1979)].   LFA does not reduce  the Cr concentration
in exchange for other heavy metal problems.

-------
 Table  3.   EPA-RCRA Leach Testing of .LFA Treated and Untreated
             Sludges


     Metals              Untreated                Treated
Arsenic
Barium
Cadmium
Chromium
Lead
Mercury
Selenium
Nickel
Copper
< 0.001*
0.23
< 0.001
7.4
< 0.01
< 0.001
< 0.001
3.9
2.4
< 0.001
0.09
< 0.001
0.81
< 0.01
< 0.001
0.002
4.8
0.02
 *  All  values  in  mg/1  of  leachate.


 LABORATORY  SIMULATION
                                                             >
     A laboratory  procedure  was developed  to  simulate the field
 sludge press.  Raw waste  slurry (1-3%) was  placed  in a blender with
 the dry stabilization reagent  (LFA,  Calcilox,  or both).  The
 mxture was placed in a high pressure  (up  to  100 psi) Millipore
 filter apparatus and  dewatered using 0.45u  filters.  The resulting
 cake was then hand molded into the  shape of a  modified Proctor
 cylinder U"x3").

     Studies were  then conducted  in  which  the  ratio of
 stabilization reagent to  dry-weight  sludge was  increased in order
 to improve  structural strength and  further  reduce  leachate
 characteristics.   A set of cylinders was produced with ratios of
 2.0 to 10 (LFA to  dry weight sludge).  On day  14, cylinders were
 leached for 24 hours  using both the  EPA-RCRA procedure and
 deionized water.   Untreated  sludge was also leached by both
 methods.  To make  the proper comparisons, care was given to make
 sure that equal weights of dry sludge solids were leached in each
 case.   Table 4 presents the  results.  Again, the fixation process
 reduced the EPA-RCRA  toxicity to below the Cr  standard of 4.0 mg/1.
 Similar reductions occurred  using D.I. H2O.  Structural DCS was
determined  at day  21  for  the 2:1 samples:  Stabilization, using
only LFA at 2:1 produced  specimens with 120 psi, while a 3 to 1
rrixture of  LFA and Calcilox  gave specimens with 430 psi UCS.

     In-Plant Field Tests;   To obtain representative samples for
each of the four field tests, the stabilizing  reagent was added to
 the sludge  holding tank prior to pumping the mixture to the filter
press.   Mass ratios of stabilizing reagent to dry-weight of plating
 sludge  is presented in Table 5.  After collection and dewatering of
 the sludge  in the  press,  sludge cake was collected from each cell
of the  press.  Then using a  pocket knife, approximately twenty 1
 inch square, 3 inch high  rectangles  were cut from the cake.   Each

-------
square was wrapped  in  plastic,  scaled,  and transported  to  the
laboratory.


Table 4.  Leaching  Studies  of  Raw and  LFA Fixated  (2:1) Cylinders
Untreated

Cr
Hi
Cu
EPA
73
65
22
- RCRA
.0*
.6
.0
Treated
EPA - RCRA
2.9
1.0
1.0
'Jnt
D.I
0
0
0
reated
. H20
.63
.61
.24
Treated
D.I.
< 0
0
0
H20
.01
.04
.07
*  All values in mg/1 of  leachate.
      All samples were cured  for  a  period  of  time at room
te.r.perature and subsequently for several  days at 105F - 100 %
humidity.  Each sample received  an equivalent of 39-46 curing days.
Following curing, two of the twenty samples  from each test were
randomly selected for extraction procedure  (EP) testing, so .that
eight,  1 inch by 3 inch, rectangles were  tested.  Samples of
untreated sludge were also collected at 3 week  intervals and were
submitted for EP testing.

      Treated samples and raw waste samples were subjected to the E?
toxicity test.  The treated  rectangles did not crack or break
during  the structural integrity  procedure  (SIP) so whole samples
were  tested.

      Random cured samples from each test  were submitted to
ur.confined compressive strength  (UCS) testing, giving UCS from 400
to 900  psi.

      The extraction procedure was  carried out following the Federal
Register, May 19, 1980, pp.  33127-28 using the manual pH adjustment
procedure.  Table 5 indicates the  amount  of  0.5N acetic acid that
was used for each sample.  Within  1 hour  of  extraction start up,
all samples stabilized to pH 5.0 t  0.2.   Following 24 hour
extraction, water was added  to bring each sample to 20 times the
original sample weight, and  filtered by 0.45 micron filter paper at
a maximum pressure of 75 psi.  Liquid leachate samples were
collected in new, soap and water washed,  twice D.I. rinsed, plastic
bottles.  Samples were placed in a cold room (40F) and delivered
to the  analytical laboratory two days later.  No preservative was
added.  All samples were analyzed  for Cr  (total), Cd, Ni, and CN as
described in EPA 600/4-79-020, March 1979 (Methods for Analyses of
Water and Wastes).

      Table 5 presents the testing  results of the raw and fixated
samples.  As expected, cadmium values were extremely low on all
samples.  Nickel was reduced from  87 and  76  ppm to 0.01 with
treatment.  These values are well  below proposed nickel standards.

-------
Tst'.e S.  KASS Ratio* of Stabilisation Reagent to Dry-Weight of Plating Sludge
Mass Ratio
*-T '* Fixating Agent
to Dry Wt.
CaJce1
X M
lass of 0.5N
Sludge Acetic Acid
Leached Added CN
LeacKate Ar-ai'jsej
(ag/1)
Cd Ni Cr Cr*'
Rav-t'nrActed  (Samples 1&2)    20


   1           5/1          32
              3.15/1
             2.30/1
27
            (Samples 3A4)     20


             2.55/1        30
30
 36.62      37      0.13    0.001 87.0   22.0


 86.27      34      <0.01    0.004 <0.01   0.03


101.71      24      <0.01   <0.001 <0.01   0.02


 98.14      16      <0.01   <0.001 <0.01   0.05


 86.98      18      <0.01   <0.001 <0.01   0.05


 33.92      37      0.05   <0.001 76.0    J.5


 82.05      30      <0.01   C0.001  0.15   0.10


 97.78      40      <0.01   <0.001 <0.01   0.0^.


 94.37      .,2      <0.01   <0.001 CO.01   0.07


 92.46      31      <0.01   <0.001 <0.01   0.07
NA'


NA


NA


NA


HA


HA


NA


NA


HA


HA
1.  Staples reooved from press before press was cocpletely fill.  Therefore, cajce thickness was less than
2.  Cr*6 not a/ialyzed on leachate saoples since it <-as found to consistently be <0.01 in p'ant waste
    flows.
         Cyanide (CN)  is not  used at  the plant.   However,  CN was  found
   at  0.13 and  0.05 ppm in the  raw sludge  leachate samples.  Recent
   priority pollutant scans  on  the waste effluent have  shown CN  to be
   < 0.04 ppm.   CN was < 0.01 on all  treated sludge samples which
   demonstrates that  the process also retards leaching  of low  level
   cyanides.

         Total Cr was  reduced by fixation from 22 ppm  to between  0.02 
   0.05  ppm on  one sludge sample, and from  3.5  ppm to 0.02 - 0.10 ppm
   on  the second.   Cr+b was  pot analyzed because from the period
   January'- March 1981, Cr+& in the  plant  waste water  has
   consistently been  less than  0.01 ppm.   In that same  period, the
   final liquid effluent has ranged from 0.038  - 0.065  for total Cr.
   Cr  b  was analyzed  by the  DPC spectrophotometric method (Standard
   Methods #14).   The  treated sludge  leachate levels of total Cr are
   all less than 0.10  ppm.    Even is all Cr  was  Cr 5 (which is highly
   unlikely), the  RCRA standard according to the October  30, 1980,

-------
 Federal Register, would not be violated.  Note that total Cr
 leaching is minimized as the stabilization reagent mass ratio is
 increased.   Earlier studied raw sludges which leached total' Cr
 ranging from 7.4 - 73 ppm leached less than 0.05 ppm after
 treatment.   For Ni, the earlier studies shewed raw sludge leaching
 from 4-66 ppm, whereas treated samples were below 0.07 ppm.
 These results confirm those found in this phase of the study.

      Further, the leached,  treated rectangles were still physically
 intact and  sound following  the leaching.  We believe that this
 waste no longer violates hazardous waste criteria.


      The Multiple Extraction Procedure (MEP):   The MEP utilized  in
 this testing is described below.   All samples were ground to  less
 than 150u.   Results of  the  MEP and EP are shown in Table 6.

 1.   Grind sample to particle size capable of  passing through  100
     mesh screen (150u).

 2.   Run the EP  Toxicity test on this  sample  (minimum sample size
     100 grams)  as described in Test Methods  for  Evaluating Solid
     Waste  (SW-846).                                   '

 3.   Analyze the extract  for the constituents  of  concern  listed in
     Appendix VII  (40  CFR 261.32/.33)  using the  analytical methods
     indicated in  Test Methods  for  Evaluating  Solid  Waste  (SW-846).

 4.   Prepare a synthetic  acid rain  extraction  fluid  by  adding a
     60/40 weight  percent mixture  of sulfuric  acid  and  nitric acid
     to  distilled  deionized  water  until  the pH  is 3.0   0.2.

 5.   Next  weight the  solid phase of the  waste  sample  remaining after
     the  Separation  Procedure of  the EP  and place it  in the
     extractor with  20 times  its weight  of  the synthetic acid rain
     extraction  fluid.  Do not  allow the  material to  dry before
     weighing.   Use  the same  extractor as  used in the EP.

 6.   The  pH  should be  recorded  between  5  and 10 minutes after the
     solid material and the  synthetic acid  rain are placed in the
     extractor and agitation  has been started.

 7.   Agitate  the mixture  for  24  hours.  Maintain the temperature at
     20-40C  (68-104F) during  this time.   The pH should again be
     recorded at the end  of  the  24 hour extraction period.

8.  Separate  the material in the extractor into its component
     liquid  and  solid  phases  as described  in the Separation
    Procedure of the  EP.

9.  Analyze  the extract  for  the constituents of concern listed in
    Appendix VII, using  the  same analytical methods as used for
    analyzing the EP extract.

10.  Re-extract the solid material remaining after extraction  with
    the synthetic acid rain  8 additional times.  Use the same

-------
    procedure  for  these  additional extractions and analyses as used
    in the  initial  synthetic  rain .extraction.

11. If after completing  the 9th synthetic  rain extraction the
    concentration  of  any of the listed constituents of concern is
    increasing over that found in the 7th  and 8th extractions, the.-.
    continue extracting  with  synthetic acid rain until the
    concentration  in  the extract ceases to increase.

12. Report  the initial and final pH of each extraction and the
    concentrations  of each listed constituent of concern in each
    extract.

     Table  6 summarizes  the EP and MEP data.  All nickel values
were less than 0,001  mg/1.  Total Cr showed a maximum of 0.82 mg/1
Table 6.  EP and Multiple  (Acid Rain) Extraction (MEP) Data
Sludge Extraction
Sample Namber
1 KEP)
2
3
4
5
6
7
8
9
2 KEP)
2
3
4
5
6
7
8
9
3 KEP)
2
3
4
5
6
7
8
9
Nickel
(mg/1)
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
Total Cr
(mg/1)
0.12
0.58
0.82
0.77
0.59
0.52
0.35
0.29
0.26
2.3
2.5
2.1
1.85
1.55
1.22
0.94
0.67
0.50
0.57
0.74
0.76
1.29
1.32
1.28
1.12
0.86
0.77
Cr46
(mg/1)

*
0.82
*
*

*
*
*
1.6
*
*
1.6
*
*

*
*
*
*
*
*
1.25
*
*
*

* not analyzed

-------
 for  sludge  sample  1,  1.32  mg/1 for sample 2,  and  2.5  mg/1  for
 sample  3.   Cr4  was  analyzed for four samples and  ranged from  7C%
 to  100%  of  the total  Cr.   Total Cr and Cr b  in the  extracts  arc  all
 -ell below  5.0 mg/1.

      For the MEP (acid  rain) leaching,  sample 1 peaked on  total  Cr
 ~r.  extraction  3,  sample  2 peaked at  extraction 5, and sample 3
 peaked  at extraction  II  (i.e., the EP).

      There  appears to be  higher total Cr  values leached from sludge
 samples  2 and  3  than  for  1.   Sample 1 was prepared  at a 5:1 mass of
 fixating agent to  dry weight sludge ratio, while Sample 2 was at a
 ratio of 3  to  1  and  Sample 3 was at 2 to  1.   Since  a  pozzolonic
 reaction is believed  to be occurring,  a stronger product appears to
 i>e  produced at a higher reagent to sludge ratio.  Also, Cr and Ni
 probably participate  in the  silicate  reactants so that more
 stabilization  reagent presents more reaction  sites.

      In  summary, as  in  the earlier cases  (regular EP  testing and
 crushing tests), these wastes do not  appear to be hazardous when
 compared to EPA  regulations.   It is recommended that  the treated
 waste be delisted.
ECONOMIC EVALUATION OF FIXATING  AGENTS

     An economics analysis  using  the various stabilization agents
was also conducted.  For  the  analysis, a  1:1 ratio of fixating
agent to dry weight plating sludge  is assumed.  If a higher ratio
is used, the comparative  analysis is still valid.  The costs are
based on creating about one ton  of  treated waste per day (the
typical generation rate of  wet sludge, about 400 pounds per day,
dry weight).  Table 7 presents the  results:


Table 7.  Cost Comparison of  Fixating Agents with a 1:1 Mass
            Ratio
Additive                     Per Ton Cost     Cost per wet ton
                                                $400/wet ton
Cement
Sodium Silicate
Lime
Calcilox
Lime & Fly Ash (Bulk)
Lime & Fly Ash (Bagged)
$70.00
$250.00
S60.00
$50.00
$12.50
$25.00
$14.00
$50.00
$12.00
$10.00
$2.50
$5.00
     Figure 1 presents the cost versus the ratio of the mixture of
LFA to dry weight sludge.  The cost  is the sum of the disposal
costs plus the chemical costs.  It does not include amortization of

-------
Figure 1. Treatment & Dispose  Costs Versus Mass, Ratio
                                        - ~| = Total Disposal Cost
O	O = Reagent Cost  $12.50/ton
                	O = Savings if Waste is Delisted
CO
CO
o
O
"o ^
o o
 t^
CD CD
0 ^
c^ Q)
^ CL
f"\ -f-..\-
CO v_^
O
CL
CO
O
100

80

60

40


20
n
i
Cost of Hazardous Waste Disposal ^ 

' o. ,''
xo^
 ^
n
-^ \ Q^^^
M' ^><^

- * ^'-^^"u ^\
^P ^C )^ "'\
^t^-> Q ^ Cost of Non-Hazardous Waste Disposal ^--^
O-J ' 	 1 	  	 -^ 	 i - - i. i  i "'.^
       02   4    6    8  10   12   14  16  18  20  22
        Mass Ratio - Reagent to Dry Weight Sludge

-------
 new capital  equipment or  O&M costs.   Also,  these costs are  in  $  per
 wet ton from the  plant.   The increase in density due to addition of
 LFA has been factored into  the disposal  costs.   Clearly,  Figure  1
 illustrates  that  up to about 20:1  mass  ratio the sludge is
 economical  to fixate and  handle as a  ncnhazardous waste.

 CONCLUSIONS

       A low  cost,  high volume,  pozzolonic lime-fly ash material  was
 blended with an hydroxide plating  sludge.   Structural  strength of
 over 100 psi was  obtained and the  hazardous characteristics of the
 sludge were  reduced to a  nonhazardous nature.   The material must be
 cured under  humid  condition  to retain moisture  for the pozzolonic
 reaction.  The  stabilization reagent  was added  to sludge  dewatered
 with a sludge filter press.


 PROPOSED PROCESS

      A modification of  the present  sludge handling system, as
 indicated in Figure 2,  is proposed.   The LFA slurry tank  receives
 stored chemicals  from the dry hopper  on  a batch  basis  and is
 blended with the  liquid sludge  from the  1500 gallon tank.  Then,
 the  sludge plus the LFA slurry  is  pumped through  a dual suction
 diaphragm pump  (at  100 psi)  to  the  sludge filter  press.  Dewatered
 sludge  is emptied  from the press into a  thick plastic  bag and then
 placed  in a  plastic lined container.  This  provides a  double lining
 to keep the  sludge  moist  for  the pozzolonic  reaction.   Each
 container is  coded,  dated, and  placed in storage.   No  waste will be
 shipped to the  landfill until  it has  cured  a minimum of 14 days.
 Permanent records of  the  date  a container was filled and when it
 was  shipped  will be maintained.  SHould  the  slurry tank not be
 emptied  on the batch  run  it  should be drained to  the raw waste
 input  line and diluted.   Records should  also be  kept on LFA
 purchases and utilization rates.


 EQUIPMENT NEEDS AND COSTS

     Referring to Figure  2,   the following capital  items will need
 to be purchased to  complete  the project.  Approximate  costs are
given:

                      ESTIMATED CAPITAL COSTS

                 Dry  Hopper  & Feed        $5,000
                 Slurry Tank  & Mixer        5,000
                 Dual Chamber Pump          3,000
                 Valves, Piping             3,000
                 Controls                   4,000
                                   Total $20,000
                                 10

-------
                                                       1500
                                                      Gallon
                                                      ss=l-3%
Filtrate
              Press

             Sludge
       Figure 2.  Proposed Stabilization Process Schematic

-------
                   TOTAL ESTIMATED PROJECT COSTS

                  Capital                 $20,000
                  Construction             20,000
                  Engineering i
                    Contingencies           10,000
                  Legal  &
                    Administrative
                  Financing

                                    Total $65,000


      A  need  for  additional  manpower to  handle  this  process  is not
anticipated.  Operation costs will  include  the  chemical costs plus
energy  to mix the  slurry tank.


RECOMMENDED  PROCESS DESIGN

      Although the  mass  ratio of 1:1 provided a  nonhazardous waste,
it is recommended  that  a minimum  ratio  of 5:1 be used to design the
process.  This may be desired sometime  in the  future due to changes
in waste quality or the  need for  a  better end product and will give
an adequate  safety factor.

      The following presents  recommended sizes of equipment:

Dry Hopper -   5 ton capacity = 111  Cu.  Ft.

Slurry Tank  -  (assume  2000/day  of  LFA $ 15% solids in slurry and
               that it  takes  2 runs  to  empty 1500 gallon tank due
               to  heavier loading on the filter) =  750 gal = 90 cu.
               ft.

Control Package -

           1.  Screwtype dry  chemical feeder - power controlled
               by  (2) As  level is reached at (2) in slurry tank
               power in  (1)  is activated and measured amount of
               dry chemical  is added;

           2.  High level controller for slurry tank - Controls
               valve from 1500 gallon holding tank.  As level is
               reached,  valve is closed and dry chemical is added
               as described  in (1);

           3.  Low level controller for slurry tank - Controls
               valve from 1500 gallons  holding tank.  As level is
               reached,  valve is opened to refill slurry tank;

           4.  Emergency Level Backup - If this control is  reached,
               purap is shut off until slurry tank is refilled.
               Prohibits filtration of pure waste;
                                 11

-------
3.   Valve - Allows filling of slurry tank from 1500
    gallon holding tank;

6.   High level indicator. (exist ing);

7.   Low level indicator (existing);

-------
5.  Valve  -  Allows filling of slurry  tank  from 1500
    gallon holding tank;

6.  High  level indicator, (exist ing);

7.  Low level indicator  (existing);

8.  Pump  - Two way dual  flow diaphragm pump -  Allows
    controlled flow of slurry and plating  sludge.

9.  Mixer  -  Controlled by  high level  indicator (2) is
    slurry tank and screw  type chemical  feeder (1).
                          U.S. Environmental Protection
                          Region 5, Library (Pi.-1.2J)
                          77 West Jackson Bc'.'!v.v. J, 1':i;.i floor
                          Chicago, IL  60604-3590
                       12

-------