United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROO/R08-90/036
February 1990
S»EPA
Superfund
Record of Decision
Rocky Mountain Arsenal
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50272-101
REPORT DOCUMENTATJON 11. REPORTNO. 12.
PAGE EPA/ROD/R08-90/036
2. A8c1p.nr. ACC8881an No.
4. nee end Subfte
SUPERFUND~RECORD OF DECISION
Rocky Mountain Arsenal (Operable
S~ ~d Remedial Action
7. AuIII
s. A8pIrt Date
02/26/90
Unit 16), CO
L
L P8rfoftnIng 0rg8nII811on ~ No.
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10. PtojIc\fT ulllWortI UnIt No.
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U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
(a)
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The Rocky Mountain Arsenal (RMA) (Operable Unit 16~comprises part of the 17,000-acre
RMA site, which is a former U.S. Army chemical warfare and incendiary munitions
manufacturing and assembly plant in Adams County, Colorado. From the 1950s until late
1969, the U.S. Army used the RMA facility to produce the nerve agent GB (isopropyl
methyl-phospho no fluoridate) . From 1947 to 1982, private industries leased major
por~~ons of the plant facilities to manufacture various insecticides and herbicides.
Si~ ~1970, facility operations primarily have involved the destruction of chemical
wai--~e materials. Because final remediation of the RMA site will take many years to
complete, thirteen Interim Response Actions (IRAs) were determined necessary prior to
implementing the final On-Post Record of Decision (ROD). Operable Unit 16 (M-1 Settling
Basins area) is one of several areas being addressed as part of the Other Contamination
Sources IRA. The M-1 Settling Basins area occupies 84,500 square feet and consists of
three unlined basins used to treat waste fluids from the lewisite facility. The basins
also may have received lesser amounts of waste materials including mercuric chloride
from alleged spills within several onsite buildings. The basins have been backfilled
and are partly covered with soil or structures. Site investigations by the Army
(See Attached Page)
17. 00cunwt1 Anal'" .. o..a;p1CM8
Record of Decision - Rocky Mountain Arsenal (Operable Unit 16), CO
Second Remedial Action
Contaminated Media: soil, sludge, qw
Key Contaminants: organics (pesticides), metals (arsenic)
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(FonMIty NT1~)
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EPA/ROD/R08-90/036
Rocky Mountain Arsenal (Operable Unit 16), CO
Second Remedial Action
Abstract (Continued)
revealed that the waste material in the basins is a source of arsenic contamination i
ground water. This ROD addresses interim remediation of source areas and management of
contaminant migration. The primary contaminants of concern affecting the soil, sludge,
and ground water are organics including pesticides, and metals including arsenic.
.
The selected Interim Response Action for this interim remedy includes sampling and
relocating tanks trom the basin area to an adjacent area to await a final disposition
in the tinal On-Post ROD; constructing a temporary 360-degree subsurface barrier such
as a slurry wall or sheet pilings around the basins; performing an in-situ
vitrification demonstration test; treating approximately 2,600 cubic yards of soil and
6,400 cubic yards of sludge using in-situ vitrification followed by carbon adsorption
to treat off-gasses; treating the recovered water driven from the sludge during the
vitrification process onsite ~t ~h~ CERCLA Wastewater Treatment System or by another
~~od to be determined during remedial design; and conducting ground water and air
monitoring. The vitrified soil will remain onsite, pending determination of a final
remedial action in the final On-Post ROD. No costs were provided for this remedial
action.
r
PERFORMANCE STANDAPflS OR GOALS: The treatment process will be constructed to provide
99.99% destruction and removal of organics. Treatment standards for effluent from the
off-gas control process and other liquids generated through dewatering of the area are
contained in the ROD for the CERC~A Wastewater Treatment System IRA. Air emissions
from the vitrification process will comply ~ith applicable Clean Air Act emission
standards. .
.
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Consutting Englneen. GeologIstS and Environmental Scientists
StanfOfd Place 3. SUIte 1000
4582 Soud'l Ulster Street Pancway
Denver. ColOrado 80237
(303) 694-2770
REQUESTS FOR COPIES OF THIS DOCUMENT
SHOULD BE REFERRED TO THE PROGRAM MANAGER
FOR THE ROCKY MOUNTAIN ARSENAL CONTAMINATION CLEANUP.
AMXRM-PM COMMERCE CITY. CO 80022.
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FINAL DECSION DOCUMENT
FOR TIlE INTERIM RESPONSE AcnON
AT TIm
M-t SETIUNG BASINS
ROCKY MOUNTAIN ARSENAL
MARCH 1990
CONTRACT NO. DAAAl5-88-~/
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Woodward.Clyde Consultants
TABLE OF CDl'n"ENTS
'"
\
Secrion
~
LD INrRODUcnON
2.0 HISTORY OF THE M-1 SETIUNG BASINS
1-1
2-1
.
3.0 INTERIM RESPONSE ACI'ION OBJECnVE
4.0 INTERIM RESPONSE ACI'ION AL11::RNA'I1VPS
>1
4-1
4.1 NO ACI'ION
4.2 MONITORING
4.3 INSTITU"ONAL CONTROLS
4.4 SLURRY WAll. wrm CAP
4.5 MUL TI1.A YERED CAP
4.6 IN srru VITRIF1CA TION
4.1 CHEMICAL F1XA TION WITH ONSITE STORAGE
4.8 CHEMICAL F1XA TION WITH OFFSITE DISPOSAL
4.9 CONCLUSIONS
5.0 CHRONOLOGY OF EVENTS
4-1
4-2
4-2
4-2
4-3
4-3
4-4
4-S
4-S
5-1
6.0 SUMMARY OF THE INTERIM RESPONSE ACI'ION
6-1
6.1 HEALTH & SAFETY PlAN
INTERIM RESPONSE ACI'ION PROCESS
6-2
7-1
8.0 APPUCABLE OR R.El.EVANT AND APPROPRIATE REOUtREMENI'S FOR THE
REMEDIATION OF ann::R CDNT AMINA 'nON SOURCES - M-1 SE'ITUNG
BASINS INTERIM RESPONSE ACI'ION
8.1 INTRODUCI10N
8.2 AMBIENT OR CHE."AICAL-SPECIFIC ARARs
8.3 LOCATION-SPECIFIC ARAR.s
8.4 ACI10N.SPECIFIC ARARs
8.5 COMPLIANCE wrm THE OTHER ENVIRONMENTAL LAWS
8-1
8-1
8-1
8-3
8-4
8-11
9.0 SOIEDUU!
10.0
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I-I DECISION FLOW CHART FOR ornER CONTAMINATION SOtJRCES IRAs
2-1 LOCATION MAP, ROCKY MOUNTAIN ARSENAL
2-2 M-l SEITLING BASINS AND LL'\fE SETrLING BASINS AREA MAP
1-2
2-2
2-3
...
(~I~Jf) ~Iccvg) (fI:&IfI/flI) (1U44)
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1.0
INTRODUcnON" '
.
The Interim Response Ac:Uon (IRA) aJtematives UY'uft'lem and decision process for the M-l Settling Basins
at the Rocky MoUD1aiA ArscD.aJ (RMA) is bciDg coaduczed as part o( the IRA process for RMA in
accordance with the Federal Facility Agreemem aDd the Tcchaica1 Program PlaD..
Determ.inatioas CDncenUng the implemcnwion of this IRA have been reached through a considcration of
the objecives of Sectioas 2.3(a), 22.5, and 22.6 o( the Federal Fac:ility Agrcement and by application of the
Decision F10w Chart for Other Contamination Sources IRAs adoptcd by the Orga.o..iz.atioas and the State
in the June 7, 1989 Subcommittee meeting (FIgure 1-1).
Altcrnatives have been reviewed based OD thcir overall protcc:Uveness of human health and the cnvironmcnt;
compliance to the maximum extem practicable with Applicable or Rclevant and Appropriate RcquiremcDts
(ARAIU); reduaioD in mobility, toxicity, or volume; short-tcrm and long-term cffcaivcness;
implcmcntability, and .cost-efrec:tivcncss, The preCerrcd IRA will coasist of coastruction of a temporary 360-
degree subsurface barrier such as a slurry wall or sheet pilings around the M-l Settling Basins area. and the
treatment of the waste materials in the basins with in situ vitriIicatioD.
1-1
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SITE CHAAACTERIZATION
''''
DOES SITE
POSE A
SIGNIFICANT RISK
TO HUMAN OR
BIOTA RECEPTORS
7
INTERIM RESPONSE
ACTION SELECTION
NO
OR DATA
INADEQUATE
NO
JOO No. : 22238-.,00
Pr-eoOrec2 tIy: K.A.S.
001.: 12/18/89
1-2
.iIIl_11 III III III I .' 1It-'- ....'~~ l..,orts.I.I.4n...S.
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MQNITORINGI M AINTENANC E
NO
YES
DECISION FLOW CHART FOR OTHERI
CONTAMINATION SOURCES IRAs
F'tQure 1-1
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2.0
HJSrOR.Y OF TIlE M-l SEn'LING BASINS,
Rocky Mountain Arsenal (RMA) ocaJpies more t.haD 17,CXXJ aaes (approximately 27 square miles) in ~dams
County, directly northeast of metropolitan Denver, Colorado (FtgUJ'e 2.1). The property was purchased by
the U.S. government in 1942 (or use in World War n to manufacture aDd assemble chemicaJ warfare
materials, such as mustard aDd lewisite, aDd incendiary munitions. Starting in the 19SOs, RMA produced
the nerve agent GB (isopropyl methylphosphonofluoridate) uatillate 1969. A signilicaat amount of chemicaJ
warfare materials destruction took place during the 19505 aDd 1960s. Since 1970, RMA bas primarily been
involved with the destruction of chemicaJ warfare materials. The last military operations at RMA ended in
the early 198Os. In November 1988, the R~tA was reduced to inactive military status reflecting the fact that
the only remaining mission at the Arsenal is contamination cleanup. In addition to these military activities,
major portioos of the plant facilities were leased to private industries, including Shell Oil Company, for the
, manufacture o( various insecticides and herbicides. betWeen 1947 aDd 1982.
The M.l Settling Basins arc loated in the South Plants are:!. just south of December 7th Avenue along the
northern edge of the northwest quarter of Section 1. The basins aDd the berms surrounding them, all of
which are DOW buried and partially built upon. occupy an area of approximately 34,.500 square'feet (Figure
2-2). For the purpose of the alternatives assessment it was estimated that approximately 6,400 cubic yards
of sludge plus 2,600 cubic yards of soil overburden would be addres.scd by this IRA.
The M.1 Settling Basins were constructed to treat waste fluids from the ~wisite facility. Two basins were
coostructed in 19~2, aDd a third basin was consuucted in 19~3 when the original [WO filled with solids. All
three were unlined, and each measured approximately 90 feet wide, 115 feet long, and 7 feet deep. In
addition to the waste fluids from the lewisite disposal (acility, the basins may have contained lesser amounts
-
of waste materials from alleged spills within the acetylene generatioa building, the thionyl chloride plant, and
the arsenic: trichloride plant, which may have been routed through floor drains aDd the coanecting piping to
the basins (Ebascc 1987). The basins also rec.cived I considerable amount of mercuric: chloride C3talyst,
possibly from a spill (Ebasc:o 1988).
The liquids discharged into the basins fl1st passed through a set of reactor towers where calcium carbonate
was added, thea through a wood trough into the M-1 SettliDg Basins where the arsenic: precipitated out of
solutioD. The liquid from the settling basins was decaated through aD 18-iJJch.diameter pipe to the Lime
SettJiag Basios in SeaioD 36 where fmal treatment occurred, before being routed (0 Basin A (Ebasco 1987).
2.1
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SCALE IN MIL.ES
JOD No. : 22238-.'00
LOCATION MAP RMA
PfotoO,..cs by: 1<. A. S.
001.: 12/18/89
Figure 2-1
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LIME SETTLING BASINS
December 7th Avenue:
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KEY MAP
JoO No. : 22238-.100
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Ooft: 12/18/89
2-3
I
M-1 SETTLING BASINS
A
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SCALE IN FEET
M-1 SETTLING BASINS AND
LIME SETTLING BASINS AREA MAP
F"tgure 2-2
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Woodward.CIyde Consultants
The M-l Seuling Basins were backfilled, probably in 1947, and are now covered with soil. Portions of the
basills are covered with structures. These struCtures will be relocated before implementation of the IRA.
Based on several investigations, the contaminants in the 'waste material in the M-l'Settling Basins are
primarily arsenic: (about 8 percent) and mercury (about 0.5 percent), with the bulk of the material being
oxides or carbonates of c:aJcium- Organochlorine pesticides and other organics have also been found in the
Dear-surface soils (Ebasco 1988). The bottoms of the basins appear to be about 7 feet below ground surface,
based OD as-built drawings and field investigatioD.\. The groundwater elevatioD in the vic:iniry of the M-l
Set~liDg Basins is appro=ately 8 (eet below ground surface. with some seasonal variation that may bring
the water table intO contaCt with the basin conteDts during parts o( the year. The M-1 Settling Basw are
a source o( arsenic contamination to the groundwater (RMA data base and WCC 1989b).
'.
On February I, 1988, a proposed ConseDt Dcaee was lodged in the case: of United States v. She!! Oil
Como3nv with the U.S. District Court in Denver, Colorado. The proposed Coa.sent Decree was revised after
public: comments were received, and a modified proposed Consent Deaee was lodged with the Court on
June 7, 1988. In February 1989, a Federal Fac:iliry AgreemeDt was eDtered into betWeen five federal
agencies: the U. S. Environmental ProteaioD Agency (EPA), the Army, the Department of the Interior, the
Department of Health and Human Services. and the Department of Justice, wlUch established procedures
(or implementing the Arsenal cleanup program as speci1ied in the Technical Program Plan. and incorporated
many provisions of the modilied proposed Coascnt Deaee. The Army and Sheil Oil Company agreed to
share certain costs of the remediatioD to be developed and performed under the oversight of the EP A. with
opportunities for participation by the State of Colorado. The long-term remediation is a complex task that
will take several years to complete- The Federal Fac:iliry Agreement specifies 13 Interim Response Actioa.s
(IRAs) determined to be necessary and appropriate. The Remediation of Other Contamination Sources is
one of the 13 IRAs. The M-I Settling Basins area is oae of several sites beiag addressed by the remediation
of other contamiaation sOurces IRA. The actioD at this site consists of asscs.sment and, as necessary, the
seleaioD and implementatioD ot an interim action.
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3.0
INTERIM RESPONSE AcnON OBJECTIVE
~
The objeCtive of the Interim R~poDSe ACtiOD (IRA) Alternatives ~ment Cor the M-l Settling Basins is
10 assess whether immediate action at this sile is appropriate and 10 re.c:ommend, if DeCt~cary. aD IRA
alternative 10 miligate the threat of release Crom the M-l Settling Basins on an interim basis. pending
determination of the final remedy in the Onpost Record of Decision (ROD).
The IRA alternatives have been evaluatcd based on the CoUowing critcria:
.
Overall protectiveness of buman bea1th and the en..ironment
.
Compliance with Applicblc or Rclcvant and Appropriatc Requirements (ARARs) to tbe mmmum
extcnt praajcable
.
RcductioD of mobilicy, toxicicy, or volumc
.
Short-Ierm and long-term effcctiveness
.
1m plcmcDtabilicy
.
Cost
TbU decision documcnl provides a summary of the altcrnative technologies considcred, a chronology of the
significant cvents lcading to the initiatioD of tbe IRA. a summary of the IRA project, and a summary of the
ARAR.s (lcgal and regulatory standards. aitcria. or limitations) associatcd with the program.
As specified in the Fedcral Facilicy Agreemcnt, this IRA will. by containing and treating a contamination
sourc:.c. 10 the maximum extent practicable, be coasistcnt with and contribwe to the efficient performance of
the rmal Response Actioa.
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Woodward.CIyde Consultants
4.0
INTERIM RESPONSE AcnON ALTERNATIVES
"4
This sectiOD describes the Interim RCSP'?DSe ActiOD (IRA) alternatives developed Us the IRA Alternatives
"f~umeDt for the M.l Settling Basins (WCC 1989a). These alternatives iDcluded:
.
No ActiOD
MonitoriD3
lAstitutiODaJ Coatrols
Slurry Wall with Cap
MuJlilayered Cap
ID Situ Vitrification
Chemic.a1 Fixation wirh Onsite Storage
Chemic.a1 rlxatioD with Offsite Disposal
.
.
.
.
.
.
.
. .
All of these alternarives were subject to an evaluatioD in the IRA. Alternatives A.\Kssment. The IRA
Alternatives Assessment for the M.l Settling Ba.sias CQacludes that there appears to be' both a long. term
techDic.a1 and cos& benefit iD performing an IRA DOW since uearment after arsenic bas spread ~mes both
more CQmplex and costly insofar as a Larger area must be addressed.
FoUowing is a description and a brief summary of the evaluatiOD of each alternative. All of the alternatives
caD be designed and implemented to meet Applicable or Relevant and Appropriate Requirements (ARARs)
to the maximum extent practicable. Details of the evaluatioD caD be found Us the IRA Alternatives
M$e"",,ment for this site (WCC 1989a).
4J. NO AcnON
This alternative consists of taking DO action to coDU.i.n or Uca1 CODt2m1ft2tcd soil and sludge at the M.l
Settllng Basins. This alternative is not CQJWdercd prOtedM: of humaD health and the environment and would
DO( reduce CODt2mlft2n( mobility, toxiCty, or volume. This alternative has DO shon-term impac:u. however,
iI also has DO long-term eff'ec:tiveDess. It could be ca.sUy implemented at DO cost. The DO actioD alternative
would Dot be Uscon.sistent with any rmal remedy at the site.
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4.2 MONITORING
This alteJ"Dative c.oasisu of c.onduc:ti.ng upgradient and downgradient groundwater sampling aDd analysis.
MoDitoring would allow coatinued tracking ot c.ol1t2min:llnt movement, thereby providi.a3 additional
iDCormation which could be used to coatinue to evaluate the protection of human bealth and the environment.
MoDitoring would not reduce c:oa'2",in2nt mobility, tozicicy, or volume. It would have minimal short-term
impacts on workers during monitoring weU inu2lhtion, which could be mitigated through the use of personal
protective cqwpment. The long-term eff'ectivenesa of this alteruative is limited to iu uSe as an indic:ator of
future impact at sensitive receptors. It c.ould be easiJy implemented at a relatively low cost. The monitoring
alteruative would not be inconsistent with any rmal remedy at the ~te. Groundwater monitoring would also
be included in all foUowing a11eruatives.
~
4.3 INsrmmONAL
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Woodward.CIyde Consultants
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This alternative is coasidered protective of human health aDd the cnvironment, since the waste material is
isolated Crom the cnvironment. Both vertical aDd horizontal contaminaat migration would be greatly
iDhibited. However, this alternative does nO( affect the tozicity of the material aDd may aaually iDacasc the
volume of materia! that may ultimately require remediation, since some of the containment materials may
Q)me in contact with the sludge. ArJy minimal short-term impacts to worken or the community could be
addressed through the use of penoaa1 protecUve equipment aDd eagiaeering coatrols. The long-term
effectiveness of this alternative is limited since this is a containment techaology that does nO( aaually remove
or treat the source of contamination. This alternauve could be implemented with straightforward coDStrUc:tioa
techaiques at a relatively moderate cost. Containment would be coasiuent with the flnal remedy bcc.ause it
would reduce-potentia1- cont~~t m~ .)(;0110
4..5 MULTIl..A YERED CAP
This alternative would coasiu of constructing a multiUycred cap over the M-I Scttling Basins as described
in subseaion 4.4. In addition, groundwater monitoring would be coaducted. , The cap would inhibit
intl1trauon of precipitation aDd surface water. However, I cap would nO( address the horiz.cntal flow of the
a1JuviaJ aquifer through the M-l Settling Basins. which is probably a more sigzWiC3Dt migratioa pathway in
this area tha.a dowaward migratioa by ini'utratioa.
This alternative is coasidered protecUve of human health aDd the environment. The cap would limit the '
downward mobility of the contaminants. However, it would ~ve no effect On the toxicity of the sludge aDd
may actually inaeasc the volume of coataminated material that would ultimately have to be treated. since
some of the cap materials would come in contact with the sludgc. There would be minima! short-term
impacts associated' with the implementauon of this altenwive, which can be addressed through the use of
penoaa1 prO(ective equipmCJ11 and eagiaeering controls. Since this is a containment alternative, the loag-
term effectiveness is limited. This alternative could be implemeDted with uraightforward CODStrUaion
techniques at a relatively low COSL Conf:llil'lf"eDt would be coas.i.ueDt with the final remedy because it would
reduce pcxential c:onf2min2nf migralioa.
4.6 IN srnJ vrrRIFICATION
This altcrnative coDSisu of coasuuaing a temporary ~gree subsurface barrier such as I sluny wall or
sheet pilings around the M-l SenliD.g Basins to temporarily bydraulic.al1y isolate the site &om the surroundiag
aquifer. The soil/sludge in the M-l SenliD.g Basins would then be vitrified by introducing UI cJcc:tric current
through a square array of cJec:uodes set in the sludge. The elec:uic cuneDt raises the temperature of the
udge to apptomuately 1600 degrees centigrade, forming a melt that subsequently cools to aD impermeable
(DWlo.Jf) (W14DaA) (a/%1'" (aMA)
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Woodward.CIyde Consultants
gJass. AzJy organics in the sludge are either pyrolyzed in the melt. rapidly oxidized at the surface of the melt.
or captured in the offgas treatment system. Most of the mercury and possibly some arsenic: would be
vapor1zcd and subsequcntly condcnsed in the offgas treatment system. The remainder or the arsenic: and the
other metals would be incorporated into the gIas.s. Air monitoriDg would be conducted during
implementation of this alternative. Groundwater mODitoriDg would also be conducted to evaluate the
coatiaucd effectivencss or" this alternative.
'#
This "alteraative would be protective of human health and the cnvironment. ContaminantS would cithcr be
destroyed in the melt process, captured in the offgas treatmcnt system. or permancntly incorporated in thc
gJas.s. The proc:es.s ~cantly reduces the cont2minaDt inobility, toxicity, and volume. There are some
shon-tcrm impac:u usoci.ated with the implcmcntation or the proc:es.s that can be mitigatcd through the use
of personal protective cquipment during construction and setUp, and throU3h proper design or the offgas
treatmcnt systcm. This altcrnative provides ror JoDi-tcrm cffectivcncss because. ror those soils and sludges
vitrified, it is a permanent trcatment and leaves no untreated waste or toxic and mobile rcsiduab on site.
The technology has gone through treatability testing. which has shoWlS itS cffectivencss on M-l Settling Basi.a.s
sludge. Implementation of in situ viuifiation would requite offgas monitoriDg to ensure the effectivencss
of the air pollution control equipment. Due primarily to the ~c:ant power requirementS to maintain thc
meJt. the costS (or this altcraative are rel.1tively high. Implemcntation of this altcraative would be consistcnt
with and contribute to the efficicnt performance or the fiAa1 response action by providini sigz1ificant interim
remediation or 'a source or contamination.
4.7 OIEMICAL FIXATION WITH ONSITE ~R.AGE
This altenwive coasisu or excavating the soil and sludge in the M-l Settling Basins by sections or subarcas,
mixing the excavated materials with oae or more rlXation agcntS to immobiliz.c'the contamiDaDu, testing the
treated portions to ensure treatmcnt cffCdivcncss, and placing the treated soil/sludge ill an oasite temporary
waste pile. The sequence would be repeated (or su..-"ive subareas until the entire area to be. c.hcmically
filed is treated. La addition. groundwater monitoring would be conducted.
AD oasite aboveground temporary Q5tc pile would be constructed to st~ the chemica11y fW:d matcrials.
For the purposes of this study, the bonom liDcr aDd lcac.bate collCdioD ~m would consisr oc. from the base
upward, aD 18-iIIch-thic:k compac:ed clay layer, . f1aib1e membrane liDcr, . syath~ti( draiDage net, aDd a
gcocwe filter fabric. The bottom layer would be doped at a minimum of 2 percent toward. leachate
coDcaioD sump. Once the chemically fixed materials ba~ been placed ill the waste pile, . cap would be
consuuc:red to dose the temporary waste pile. The cap des.igD would be. the same as that used in the
multilayered cap alteraative (subsection 4.4).
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This altcrnativc is considcrcd to be protCd.ive of human health and the environmcnt since the contaminants
would be immobiliz.cd by the fixation process. The tematy of the material Viould be reduced by the chemical
fixation. howcvcr, the volume of matcrial would increase. This alteruative provides (or long-term cffCd.ivencs.s
because, (or the fixed matcrials, it is a permancnt treatmcnt and leaves no UDtreated waste or to%ic and
mobile residuals OD site. There would be SOme shon-term impacts usoci.ated with implementation which
c:ouJd be addressed through the use of persoDaJ procCdive equipment and eagineering coatrols for odor and
dust. Although fixatioa technology is weU esublished at sites with similar wastes. treatability testing would
be required 10 ~ablish the cffeCtiveness of the lechnology oa the. specific coat.2mi"~."ts at the sUe. This
alIeraative could be implemented at moderate COSt. Implementation of this alternative would be COnsistcnt
with aDd contribute to the efficieat performance of the final response actio a by providing interim remediation
of a source o( coata.mii1atioa.
4.11 CHEMICAL fIXA nON WTI1i OFf'SrI'E DISPOSAL
This alteruative would coasiu of excavating the sludge aDd soil in the M-I Settling Basins aDd chemially
fixing the matcrials in the same maDDer dcsaibcd in subseaioa 4.7. The chemicaUy fixed materials would
theD be transponed 10 aD offsite b.azatdous waste landfill for disposal ID addition. groundwater mOlUtoring
would be conduacd 10 cvaluate the continued cffcCtivcness of this alteruative.
.'
This alteruative is coasidercd to be protCd.ive of humaD bealth aDd the cnvironmcnt since the coataminants
would be immobilized by the fixatioa proccs.s. The to%icity of the material would be reduced by the chemical
fIXation. howcver, the volume of material would increase. This alteruative provides (or long-tcrm effcaivenes.s
because, (or the materials fixed.. it is a permaDent treatment aDd leaves DO UDtreated waste or to%ic: aDd
mobile residuals OD site. There would be some shon-term impacts usociated with implemcntatioQ which
could be addressed through the use of personal proceaM equipment aDd cagineering controls (or odor aDd
dust- Although fixatioD technology is weU ~abllshed at sites with similar wastes. treatability testing would
be required 10 establish the cffectivenCSl of the technology OD the specific CODf:amifta.ats a1 the site. The cosu
associated with this technology are relatively hi3h. primarily' due to offsUe traasponatioD IDd disposal.
ImplemeDtatioa of this alternative would be coasiucnt with aDd coDtribute to the efficieDt performance of
the final respomc acnOD by providing interim remediation of a soura: of coataminatioa.
4.9 CDNa..uSIONS
III sitU vitrificatioD is the preferred alternative. A treatment is preferable to . containment alternative at this
site because the soura: volume is mown, the waste c:haraaeristics are weU-defined, there are high
DceDtratioas of coDtamiDa.au. aDd because the site is a groundwater contaminatioa source. The advantages
~IWI) (W14JIIA) CllJlrtf'l/l) (1'WA)
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of in situ vitrification arc that thc mctals arc cithcr immobilized or captured and that any organic
contaminants arc destroycd. thcreby reducing thc mobiliry, toJiciry, and volumc of the matcrial. In sit~
vitrification will effectivcly prcvent future potential cont2min:ant migration from the M-1 Scnling Basins.
Therefore, implcmcntation of this action now will yicld a te.c:hnic.a1 benefit and possibly a cost benefit, and
wi1J be co~ent with and contribute to the cfficient performance of the final response action. In addition,
data resulting Crom implementation of in situ vitrification at this site is benefic:iaJ because it will contribute
to the alternatives ~~lttent for the Feasibiliry Study.
"
Although the containment alternatives are less eost!y ill the short-term. the treatment costs during any
subsequent rmal remediation would inaease due to the inaeased volume of matcrial. which would then
wdude thc cOntainment consuuction marerUls. Chemical fixation with onsite storage. is a less expensivc
treatmcnt tec.hnology, but again. thc chemic.alJy fixed materials. as weU as the wastc pile coDStruction
materials, may nced to be movcd during the rmal rcmedy. Chcmical f1JQtion with ofTsite disposal is as costly
as the in situ vitrification, but it does nO( bave the advantage of aaually destroying the organic contaminants.,
it could result in some short-term impaas during initial aavation activities. and thcre is some potcntial for
transportation risks.
~I~.) (WI~) Ct4/rr,., C1'WA)
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5.0
amONOLOGY OF EVENTs
11
The signiliQl1t events leading to the proposed dcQs.ioa to remedi~te soils in the Mol Settling Basins as
described in Sedioa 6.0 o( this report are presented below.
Date
E"o'ent
JUDe 1987
State o(Colorado. Shell OiI"Company EPA. and the Army develop and agree,
in a June 1987 report to the Coun, to a prospective boc spot list whicb
identifies candidate Interim Response Actions (IRAs) to be conducted. The
hot spec liu coasisu of five areas (the Section 36 Trenc:hes. the Section 36
Ume Pits. the Mol Settling Basia.s. the Motor Pool Area, and the Railroad
Housing Track in the Rail CLusification Yard) re{erred to as Other
Contamination Sourc:.cs in the proposed Consent Decree (Section. 9.1,
paragraph I), and in the Federal Facility ~ecment. paragraph 2:.1 (I).
Jaou;uy 31, 1989
The Army insuucts Woodward.Oyde ConswtaDt5 (WCe) to develop plans
(or interim action investigatioa work in response to the boc spot liu. Interim
adioa investigation work includes the Mol Settling Basins.
April 1.3, 1989
A draft fU1aJ Task Plan. including the work for the Mol Senling Basins, is
submiued by the Army to the Organizations and the State for comment
April 17, 1989
field investigations begin for the Other contamination sourc:.cs IRA. Work
iDcludcs investigation o( the coor:nnin:.nt sourc:e(s) within the Mol Settling
Basins.
June 29, 1989
A fiAa1 Task P1a.a is issued by the Army with comment5 incorporated.
September 7, 1989
Draft F'uaaI AlteraatM:s .4c.~crnent o( Interim Response Actions (or Other
Coar::arnin::ation Sources 0 M-l SenliDg Basins and draft ARAR.s are distributed
by the Army to the Orvni'7::arions and the State for comment.
eptember 11, 1989
field investigatiOD completed.
~Io.)t) (MI.sJRA) <=I»f!IO) (RMA)
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November rr, 1989
November rr, 1989
December 7, 1989
February 28, 1990
March 28, 1990
~lo.31) (WI..s.IRA) (1D/at/'JO) (RWA)
Woodward-Clyde Consultants
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Draft rLOal Rcsults of Field and Laboratory Investigations Conducted Cor thc
Rcmediation of Othcr Conr~min~tion Sourc:.cs Intcrim Responsc Action is
distributed by the Army to the Organizations and thc Statc.
F'mal Alternatives AsKument of Interim Response Actions for Other
Cof'lr~mination Sources - M-t Settling Basins, is disuibuted by the Army to
the Organizations and the State with comments incorporatcd.
It'
Proposed Decision Document for the Interim Responsc Action at the M-l
Settling Basins at the Rocky MOUDtam AncnaJ..is.-disuibuteci-by th~Army-to
the Organizations and the State for comment.
Public: meeting on the Proposed Dec:ision Document for the Interim Response
Action at the M-1 Settling Basins at the Rocky Mountain Arsenal.
Craft Final Decision Document (or the Interim Response Action at the M-
t Settling Basins at the RoCky MountamArsenal is disuibuted by the Army
to the Organizations and the State with comments incorporated.
The Dec:isioQ Document (or the Interim Response Action at the M-l Settling
Basins at the Rocky Mountain Arsenal is rUlalizcd and disuibuted by the Army
to the Organizations and the State.
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6.0
SUMMARY OP THE INTERIM RESPONSE AcnON
.
Performiag in situ vitrificatioa ac the M-t Settling Basias is the chosea alteraative. This is I technically
feasible alteraative that destroys the organic coa,~",in2n'J and permaneatly immobiliz.es or captures the
metals present in the M-t Sett.lia.g Basias. This alteraative provides for loag-term effectiveness beausc, for
the soils and sludges vitrified, it is a permanent treatment and leaves no uaueated waste or temc and mobile
r~dua1s oa site.
Prior to conducting the in situ vitrification operations. several tanks CUlTently situated over the M-t Settling
Basins will be relocated to an adjacent area oC the South PlantS to await a demolition and disposal
determination in the fU1a.l ODpost Record of DecWon (ROD). Sampling of the tanks may be required prior
to their relocation for bealth and safcryrC3.S0DS. The method and quantiry of sampling will be determined
during tbe design of this IRA.
A temporary 360-degree subsurface barrier, such as a slurry wall or sheet pilings. will be consuuC1ed around
the M-t Sett1iag Basins and keyed .into the Denver Formation. This will provide a temporary barrier to
bydraulic.a11y isolate the !DateN! in the basins Crom the s~ounding aquifer durmg the in situ vitrifiation
process. AD in situ vitrification demoasuation test will thea be performed on site.
Following completion of the demoasuation test. the sludge will then be vitrified in stages by introducing an
electric CUlTent through a square atTay oC electrodes (apprOJimate1y 20 feet by 20 (eet square) set in the
sludge.. The electric: CUlTent will raise the temperature of the sludge and surrounding soil to approximately
t600 degrees centigrade, formiag a melt that subsequently cools to form an impermeable glass. Ally organics
ill the sludge are either pyrolyzed in the melt or cap«ured in the offgas treatment system. MOSI oC the arsenic
and the beavy metals will be incorporated into the gW$. MOSI oC the merc:ury and some of the arsenic: will
bC vaporiud and subsequeatly condensed in the offgas treatment system. The vitrificatioa will be performed
to a depth at lcasI to the boaom of the basias. U the groundwater table is below the boaom 01 the basiDs.
the melt may extend to a maximum depth equal to the groundwater table elevation. The CDCI depth will be
dctermiDed duriDa the d.csip and implemeatation of this IRA.
The vitrificatioa process will be condUCIed under I bood that will be operated under vacuum coaditions and
be designed with redundancy to prevent any re1cascs or the offgas to the atmosphere. The offgas control
system will cool. scrub, and filter the vapors coUected Crom the off'g=,uing melt.
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Assuming this process drives off the water CractioD of the sludge, coDdeased water, will be recovered. The
coDdensate will have elevated coDceDuations of arsenic aDd mercury, as wcll as aD alkaline pH. This will
require UeatmcDt to rcduce arsenic aDd mcrcury levels to acceptable divh~rge limits. Mcrcury may be in
a .recoverable Corm. Acrua1 wastewater UeatmcDt will be determined during dc.sigD aDd may be performed
at the CERCLA Wastewater TreatmeDt Syuem.
»
NODCODdcased gases will be absorbed in a packed scrubber colWDIL As a fiDal seep in the air pollutioD
coDuol sequeDce, the exhaust gases will pass through aD activated carboD absorber prior to veDting to the
atmosphere.
Air monitoring will be coDduaed during implemeDtatioD of this alteruativc. A groundwater mODitoring
program will also be implemcDted (0 evaluate the coDtinued effeaiveDcss o( this alteruative.
6.1 HEAL 11i &. SAFETY P1J\N
A Health &. Safety Plan bas beeD developed Cor the preventioD o( oa:upatioaa1 injuries aDd illnesses during
field aaivities at RMA. This plan addresses health aDd safety requiremeDts 01 coDuaaors and their
authoriud subcanuaaors. Comp1Wsce with this plaa will be compulsory, aDd the coDuaaors will be
responsible (or selI-eDforcemeDt aDd comp1Wsce with this plaa. The Health &. Safety Plan was developed
taking into consideratioD known hazards as well as poteDtial risb. Comprehcnsive eDvironmeDtal moDitoring
aDd site-spcc:ific persoDal proteaioD are combined in aD effort to best protea workers.
. A site-specific Health &. Safety PlaD Cor work to be performed 021 the M-l Settling Basi.a.s during
implemeDtatioD of this IRA will be developed.
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. 7.D
INTERIM RaPONSE AcnON PROCESS
With respea to the Interim Response Action (IRA) (or the remediation o( other contamination sources Cor
the M-l Settling Basins ae Rocky MO\1Qeaia Arsenal (RMA), the IRA proce.s.s is as (ollows:
1.
The scope o( the IRA is desai~d in the June 5, 1987 report to the UJUrt of the United,States (the
AnDy and EPA), Shell. and the State in Un ired Srares v. Shell Oil Co. A similar desaiption is included
in the proposed Consene Deaee, paragraph 9.1 (1), and the Federal Facility Agreemene (FFA),
paragraph 221 (I).
2.
The Organizations and DOl shall nave the opportUniry to partic:ipate, at [~e RMA Comminee level. in
the identilicatioD and seleaioD o( Applicable or Relevant and Appropriate RequiremeDts (ARARs) that
may be applic:able to lRAs.
The Army issues the proposed DecisioD Document Cor the IRA (or the interim remediatioD of other
contaminatio~ .sour~s. M.I Settling Basins. (or a 3O-day public: comment period. Duril1g the 3O-day
comment period, the Army will hold ODe public meeting add(essing the IRA dec:isjon. The proposed
DecisioD Document is supPOrted by an administrative rec:.ord.
4.
Promprly after the close o( tbe comment period, tbe Army shaH transmit to the otber Organizations.
Dep3rtment o( Icterior (DOl), and the St3te, a Draft Final IRA Decision Documene for the remediation
o( other c:.ontamil1ation .sour~s. M.I Settling Basins.
5.
Within 10 days after the issuan~ of a Draft Final IRA DecisioD Documene for the interim remediation
of other contamination sourc:cs. M.I Settling BasiJu. an Organization (including tbe State it it has agreed
to be bound by the Dispute Resolution proces.s, as required by the FFA. or DOl under the provisions
set (orth in the FFA) may invoke Dispute Resolution.
6.
After the close of the period for invoking Dispute Resolution. it Dispuee Resolution is DOC invoked. or
after the completion of Dispuee: Resolution. if invoked, the AnDy sAaJJ wue a rUlal IRA Decision
Document to the: other Organizations. DOl, and the State. The AnDy shaJ1 also notify the public of the
availability of the rU1al IRA Decision Document with the supporting admiaistrati~ record. Oaly
preliminary design work (or the IRA may be conduded prior to the issuance of the rUlal IRA Decision
Document.
(~~I~Jt) (Ml.7JRA) (=/19/'110) (RMA)
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7.
The IRA Decision Document for the remediation activity at the M-l Settling Basins will be subject to
judicial review in accordance with SecUon XXXIX of the Federal Facility Agreement except where such
review is barred by Sections 113 and 121 of the Comprehensive Environmental RespoQSC, Compensation
and Liability Act of 1980 (CERClA), as amended, 42 U.s.C. Sections 6913 and 9621.
8.
Following issuance of the final IRA Decision Document. the Army shall be the lead party responsible
for designing and implementiJ2g the IRA in conformance with the Decision Document. The Army shall
issue a draft IRA Implementation Document [0 the DOl, the State, and the other Organizations for
review and comment. The draft Implementation Document Y1all include fU1al drawings and
~~c:i1ic:a[ion.s. f1l1~ign analysis, a-cost estimate, and IRA deadlines for implementation of the IRA.
..
9.
If any Org:J.Diz.ation (iDc1uding tbe State) or tbe DOl believes that the IRA is being designed or
implemented in a manner that will not meet the obj!=ctives for the IRA set forth iD the Final IRA
Decision Document, or is otherwise not beiJ2g properly implemented, it may so advise the others and
shall recommend bow tbe IRA should be properly designed or implemented. Any Organization
(including the State, if it bas agreed [0 be bound by tbe process of Dispute Resolution, as required by
the FF A. or the DOl under tbe circumstances deflDed in .the FF A) may invoke Dispute Resolution to
resolve the dis4greement.
10. As lead Party for the design and implementation of this IRA. the Army will issue the fU1aJ
Implementation Document, as described above, and will be responsible for implementiDg the IRA in
accordance with the IRA Implementation Document.
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8.0
APPUCABLE OR ~ANT AND APPROPRIATE REQUtREMENTS
FOR 'mE REMEDIATION OF amER CONTAMINATION SOURCES-
M-l SETnJNG BASINS INTERIM RESPONSE AcnON
.
&.1 INTIlODUcnON
These Applicable or RclCYW and Appropriate Requirements (ARARs) addres.s the M-l Settling Basins.
. specific area Micntified (or remediation prior to the issuance o( . Record o( Decision (ROD) (or the
Onpost Operable Unit o( the Rocky Mountain Arsenal The action described in this document is interim.
lubject to further remediation as identified in the Onpost ROD.
&.2 AMBIENT OR an:;MICAL-SPEaF1C ARARS
Ambient or chemial-spcc:ific requirement! set conceuuationlimitS or ranges in various environmental media
for specific h.az.a.rdous substances. poUut;mu. or cont~",,;"2"tS. Such ARARs either set protective cleanup
levels (or the chemic3ls o( concern in tbe designated media or indicate an appropriate level of discbarge
based on technologic:a1 considerations.
'The objcaives of this IRA arc discus,scd in the FInal As.snunent Document and Final Decision Document..
This IRA will be implemented prior to the final remediation to be undertaken in the contcn o( the 00p05t
Operable Unit ROD. 'The media of concern bere arc the air emissions [rom the system bood. the liquid
effiuent remaining after completion of the off-ps conuol process (see Section 6.0), any liquid generated
through dewatering of the area. and the soils which will be subject to the vitrification process. However, DO
ambient or chemial-specific ARARs were identified concenW1g levels of contaminants (or soils which bave
been vitrified. Section 8.4 discu5-~ action-specific ARARs for the vitrified mass that remains after
ueatment. The liquid effluent and any other liquids generated are 10 be treated by the CERClJ\
Wastewatcf Treatment System under development at the Ancna1and ueatment standards for liquids treated
by that system are contained in the ruW Decision Document for that IRA. These standards do Dot become
fiDa1 until the completion of the decision document process for that IRA. which is currently underway. The
selected alternative docs not include a groundwater treatment system.
8.2.1 Air Emi~~ions
The treatment system will result in air emissions, which result from the ueatment process. These emissions
will be contained during the treatment prQa:ss. be subject to treatment themselves and then be released 10
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the atmosphere after treatment. The standards identified below addrw the emwions from the emwions
control system which will operate as part of this IRA treatment system.
The standards contained at 40 CFR Part SO were revi~ and determined to be neither applicable nor
relevant and appropriate to apply ill the contCJa of this IRA. These sundards apply to Air Quality Control
RegioDS, large air masses which are markedly diui",ilar from the area that may' be affeded by the operation
of aD off-gas conuol system which is iDtcnded to be used for treatment by this IRA system. The specific
compoW2ds addressed by these sundards. sulfur cmdes. carbon monoxide, ozone, nitrogen oxide and lead
are nOC aDtic:ipated to be coDUiDed ill significant amoW2U ill aD}' pocential air emissions. These standards
are def1l1ed ill terms of measuremenu ill large air masses aDd nOC generally applied to specific emwioD.S
sour~s.. such as smokestacks aDd awomobile tailpipes. but to the AQCR as a wholc, so are nOC considered
relcvant aDd appropriate to apply to the type of emission source which is intcnded to be uUliz.cd in the
conte:a of this rRA. Othcr speci1ic standards have been identified as being appropriate to apply to this IRA
treatmcnt system aDd are identified below.
..
The standards contained at 40 CFR Pans 60 aDd 61 were reviewed aDd determined nOC to be applicable to
operations conduded as part of the treatment by this IRA system. These sundards apply to specific sources
of thc listed poUutanu. For cumple, Subpart E of 40 CFR Part 61 applies to sourc:.es which proces.s mercury
ore to recover merc:ury and other spec:i1jc processes aDd the arsenic prO'lisions of Subparts 0 aDd P of this
pan apply to very specific pWw., smelte.n or fac:ilitics. Since the operations contemplated by this IRA
treatment system are extremcly dis.similat Crom the pr()t'~~s identified aboYe as described in 40 CFR Part
61, these standards were also nOC considered to be relCV1J1t aDd appropriate to apply to this IRA treatment
system. However, Subpart N of Part 61 applies to glass melting furnaces which use commercial arsenic as
raw material The treatment system contemplated by this IRA is neither a glass melting furnace nor uses
commercial arsenic as raw materia!. making this subpart nOC applicable. The vitrificauon proces.s does result
in the aeation of a glass-like material ill the groW2d aDd there is a sigDificaDt amoW2t of arsenic in the soil
which will W2dergo viuificatioa. These CODSidera,tioDs lead to the determiAation that the arsenic emi.uions
from the vitrification procesa should be subject to the ~miuinns li",il21ioas contained ill 40 CFR S 61.162{b)
(2) aDd this ~dion is considered rc1eYaDl aDd appropriate to apply to this IRA. Aa:ordiDgly, arsenic
emissions will be ooaveyed to a conuol device aDd reduced by aIleasI8S%. Specific moaitoriDg and control
devices to be tIIm7j8~ will be developed during the desip IDd imp1ememacion proccs.s, as more iDCormation
aDd test data is available.
The Army has identified the standard coDUiDed ill 5 CCR 1007-3, regu1a1ioa 8, as relevant aDd appropriate
to apply to merc:ury emissions Crom the trea.tment sy'5Iem aDd as more stringent than comparable Cederal
requiremenu. This regulation is nOC applicable siDce the IRA treatment syst~m will aOC use mcrc:ury, as
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dermed by the regulation. Mercury emissions will not acced 2:300 grams/five pounds per day,. c:onsistent
with this requirement.
..
The Army has identified thc sundard {or particulate emissions c:oDUined in 40 CFR S 264.343 as relevant'
aad appropriatc to apply to this IRA treatment system. This requiremcnt is aot applicable ~ce it applies
to iaciacrators, which are different from thc treatmcnt system to be iD.sta1led as part of this IRA. However,
the particulate emissioD Slaadard is c:onsidcred relcvmt aad appropriate to apply to. this IRA treatment
system. Aa:ordiDgly, particulate emissions Crom the treatment system will be limited to 0.08 grains per dry
"mdard cubic {OO(.
The Army intends to develop performance Slancbrds {or the system hood during the design and
implcmcntation pba.sc ol this IRA when more data is avaiUble c:oncenUng the spec:ific equipment which is
to be utilized lor this IRA. The Army will eoordWtc this aaion with the other Organizations and the State.
Other standards (or to(al organic destruaioD efficicncy and opacity are discussed in seaiOD 8.4, actio a-
specific ARARs.
8.3 LOCA TION-SPECFYC ARA.RS
Location-specific requirements set restriaioDS OD aaivitics. depeDding OD the characteristics ol the site or
the immediate enviroamenl, aad funaiOD like actioD-specific requirements. Alternative remedW actions
may be restricted or precluded. depending OD the locatioD or charactcrisaic o( the sitc aad the requirements
that apply to it.
Paragraph 44.2 o( thc Fedcral Facility Aireemcnt prcM~ that -wildlifc babitat(s) shall be preserved and
managed as n~.('~u2ry to proted endangered species o( wildlifc to the alcnt required by the Endangered
Species Act (16 U.s.c. 1531 ~.), migratory birds to the alent required by the Migratory Bird Treaty
Act (16 U.s.c. 703 ~.), aad bald eagles to the e::uenr required by the Bald Ea31e ProtCdioD Acz, 16
U.s.C. 688 ~..
While this prOYisioD is DO( aa ARAR. the swwory requircmcnts themsc!\a are ARAJU. applicable to this
IRA aad will be complied with. Based OD where this treatmCDt systcm is likely to be loaled the Army
believes that this IRA will have DO adverse: impac:f OD aay end.aqered species or migratory birds or OD thc
protcaiOD of wiJdIiIc habitats. CoordizwioD will be maintained with the U.s. FISh and Wildlife Service to
DSUle that ao such adverse impac:f arises from implcmentation of this IRA.
(""10031) (Wlo&.111A) (rAlrt,.,
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The Army considers relevant and appropriate and will comply with 40 CFR 6.302(a) and (b) concerning tbe
location of this treatment system. avoid.ing the coasuuction of such system in a manner the would bave an
adverse impact on wet1a.ads or be withiA a flood plaia.
The regulations at 40 CFR 2:30 were reviewed aDd determined nO( to be applicable withiA the contCU of this
IRA because no discharge of dredged or fill material into waten of the United States is contemplated.
Be~use these regulations address only the disposal of such materials into the waten of the U aited States.
which is nO( contemplated, they are nO( considered to be relc:vmt aDd appropriate to apply in the context
of this IRA.
~
The regulations at 33 CFR 3:.0.3:30 were reviewed aDd determined to be neither applicable nor relevant and
appropriate beause they address actions a.ff~ing the waters of the United States. No such actions are
contemplated withiA the contCU of this IRA.
8.4 ACI10N-SPECIF1C ARARS
8.4.1 Dcsrnptioa
Performance. design. or other actioa-specific requirements set coatrols or restriaions oa activities related
to the management oC hazardous substances. poUutants.. or coatamiDanu. These action-specific requirements
may specify particu1a.r performance levels. actions. or tcchDologies as weU as specific levels (or a methodology
Cor setting specific levels) (or discharged or residual chemic:a1s.
8.4.2 Constnlction or Trc3tment S~tcm
8.4.21 Air Emissions
The coasuuctioa alIA in-siN vitrificatioa system does DOC UlwiYe ~i!P'ificaDt aavatioa in the area oa the
M-l B:acinc.. providing very lin1e potential (or the generatioa ol air emissions during coasuucti011. On the
remote possibility that there may be air emissions during the course of the coasuuction of this treatment
system. the Army has reviewed aU potential ambieac or chemic:a1-speciJic air emission requirements. As a
result oC this review, the Army (oUDd thai there are, at prcsezu.. ao Natioaa1 or State ambieac 'air quality
standards currently applicable or rclcvaDt aDd appropriate to any of the volatile or semivolatilcs chemicals
in the groUDd water (oUDd in the area in which CODSU'UCtioa is coacempwcd.
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.
In the .eoat'" of this IRA. there is oaly a very remoU>S of ~ micrograms per cubic me.er (illlDuai geometric mcan) aDd thc
....,dard of 150 micrograms per cubic meter.. a maximum 24-bour eooc.eauatioa ..;nool be e>«eded morc
lhaA ODte per year.
8.4.2.2 Worker ProtectioQ
The provisiollS of 29 CFIll901.UO are applicable '0 _ken at the site beause these provisioos .pecifically
address hazardous.\IbsIaIIc.e rcapo"'" opentiollS WIder CERaA 11 should be DOled thai these activiuca
are prescotly gavensed by the iDIerim rule foUDd II 29 CFIl191o.UO bu1 thai by the lime IRA activity
_ea- at the sit.. the 6aal rule foUDd at 54 FR ~ (March 6, 1989) ..;n be operatM:. ("Ibc 6aal rule
becomcs cffccUve OD March 6, 1990.)
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. 8.4.2.3 General ConstructiQn Acthities
The foUowing performance, design, or Other actioa-specific State ARARs have beea preliminarily identified
by the Army as appliable to this portioa of the IRA and more stringent than any applicable or relevant and
appropriate federal staDd.ard, requirement, criterioD, or Limiutioa:
.
.
Colorado Air PoUutjon Control Commiuion Regulatioa No; 1. 5 CCR 1001-3, Part m(D)(2)(b),
Consuuc:rioa Ac:ivitjes:
a.
Applicabwry - Attainmeat and NOIWL1iDment Ateas
b.
General Requirement - Ally owner or operator engaged in clearing or leYeliq of land or
owner or operator of laad thai bas beea cleated of greater than oae (1) aae in
aoaaua.U1mezu areas (or which fugitive pattic:uJate emiuioDS wiU be emitted ~ be required
to use aU avaiUble and prac:riaJ methods which are techDologic:aUy feasible and ccoaomic:aUy
reasonable ia order to minimize: such emi.s.sioa,s. in ICC)rdaace with the requirementS of
Sec:rioa m.D. of this re~tioD.
Co
Appliable Emi.s.sioa Llmitatioa GuideLiae - Both the 20% opaary and the no off-property
trampon emiuioa limjutioa guideLi.acs shall apply to coasuuc:tioa activities; exccp( that with
rcspecz to sources or ac:ivitics n~ed with consuuc:rioa (or which there are separate
requirements set (orth in this regulation., the emiuioa limitatioa guideLiacs there specified
as applicable to such sources aad ac:ivitics sh.alJ be evaluated (or compliance with the
require meatS o( Sectioa m.D. of this regulatioD. (Cross Re(ereace: SubsectioDS e. and f.
of Sec:rioa m.D.2 of this re~tioa).
d.
Coatrol Measures and Operating Procedures - Coatrol Measures or operatioaaJ proa:dures
to be employed may iDdud.e bUt are DO( DCO-.etrUy limited to planting Yegctatioa cover,
providiag synthetic ~ri watering. chemical subilizacioD, furrows, compacting. ",inimi~ng
disrurbed area in the winter, wind breaks, aad Olber methods or tedWqucs.
Colorado Ambient Air Oua1icy SWidatds, 5 CCR 1001-14, Air Oualiry Regulatioa A. Diesel-
Powered Vehicle Emissioa SWSdards (or Vw"ble POUUUDts:
a.
No persoa ~ emil or ause to be emitted iDeo the atmosphere (rom aay diesel-powered
Yehicle aay air coataminant, (or a period grca1er than 10 consecutive secoads, which is o(
~lo.J8) (NI.&JRA) «(JJfrt/9O)
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such a shade or densicy as to obscure au obServer's vision to a degree in excess of 40%
opacity, with the excepuon of Subpart B below.
b.
No person s.halJ emit or cause to be emitted into the atmosphere from any Daturally aspirated
dieseJ-powered vehicle of OYer s.soo Ibs gross vehicle weight rating operated above 1,())) fect
(mcu sea level), auy air cont.2lft;ft!U'r for a period of 10 CODSCC\luve seconds., which is of a
shade or density as to obscure aD observers vision to a degree in excess of 50% opacity.
c.
Diesel-powered vehicles ~~~iftg these requiremenu s.halJ be exempt for a period of 10
minutes, if thc emissions are a Wed result of a cold engine stan-up and prcMded the vehiclc
is in a stauonary posiuon.
d.
This standard s.halJ apply to motor vehic;Jes intended. designed. aud manufaaured primarily
(or use in carrying passengers or cargo on r~ds., sueeu. and highways.
Colorado Noise Abatement Statute, C.R.s. Sectioa 25-12-103:
a.
Each activity to which this article is applicable s.halJ be conduaed in a maDDer so that any
noise produced is Dot objeaionable due to intermittence, beat (requcncy, or shrillness.
SoUDd levels of DOise ra~ting from a property line at a distance of tWenty-five feer or more
there from in excess of the db(A) ~ab1isbed for the following time periods aud zones shall
constirute prima facie evidcDce tJw such noise is a public Duisaace:
1:00 a.m: to 1:00 p.m. to
~ nett 1'00 D.m. Dett 7'00 a m
ResidezWaJ 55 db(A) 50 db(A)
u>mmcrciaJ 60 db(A) 55 db(A)
LigJu Indusuial 70 db(A) 6S db(A)
Indusuial 80 db(A) 15 db(A)
III the boW'S berweeD 1:00 Lm. IDd the ac= 1:00 p~ the noise IcYeJs permined in.
subscuion (1) of this seaion may be macased by tea db(A) (or a period of DOC to acced
fifteen minwes in any oae-hour period.
Periodic, impulsive, or shrill no&scs shall be considered a public nuisance when such Daises
arc at a soUDd leveJ of rIVc db(A) less tb.aa those listed in Subpart (a) of this section.
(~lo.Jf) (WI~) (am f9tl)
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"\
d.
CoasUUctiOD projccu shall be subject to the maximum permiuiblc DOise levels specificd for
iIIdusuiaJ l.oDCS for the period within which COasUUctiOD is to be completed pursuant to any
applicable coasuuction permit issued by proper authoriry or, if DO time limitatioD is imposed,
(or a reasonable period o( time (or completion o( the project.
Co
For the purpose of this article, measuremeDts with sound level meters W11 be made wbeD
the wiDd velociry at the time and place of such measurement is DOC more than five miles per
hour.
-"
c.
In all sound level measurements. coasidcration W11 be giVeD to the effed of the ambicDt
DOise level aeated by the eDcompassing DOise of the eDvironmcDt from all sources at tbc time
and place of such sound level measurements.
In substantive fulfillment of Colorado Air Pollution Conuol Co",,,,iuioD Regulation No.1. this IRA will
employ the speCfied methods for mini",i7ing emission from Cud burning equipmcnt and coasuuaioD
activities. ID substantive fuU"illmeDt of Colorado's Diesel.Powered Vehiclc EmissioD Standards. DO diesel
mocor vehicles usociated with the coasuuction sh.aU be operated in manaer that will produce emissioas in
excess o( those specified ill these standards.
The noise levels pertineDt for COasuuctiOD 3aMry provided in C.R.S. Sectioa 25. U.l03 will be attained in
accordance with this applicable Colorado statute.
8.4.2.4 Wetlands ImQljc:1tioD.5
Through estimatioa of the geaeral area where any system would be locatc:4. the Army does a9C believe that
any wetlands could be adversely affected. However, until a final d.e.sigD is seleded and a fiaa1 siting decisioD
made, it caDDO( be defiait.ively determined that DO impad oa wetJaDds will oc.c:ur. U the fiDa1 site se~a
and/or design resulu in aD impact OD wetJaDds, the Army will review the regulatory provisions coaccraiag
wetlands impad aDd other appropriate guidance. aDd will proceed iD . manaer coasiuent with those
provisioas. CoorcWwioD will be m:ain'a;ned with the U.5. F"tSh and Wild1ile Servic.c coac:erniD8 any poteatial
impacts OD wetlands.
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8.4.2..5 t :1nd DisoosaJ Restrictions aIld Removal of Soil and Debris
There are DO actioD-sPecific ARARs that pertain to the acavation of soil duriD3 the COasuuctiOD of this
treatment S)'Stem which caD be specific:ally ideatified at this time. IA any event. very little such activity is
caDlemplated by this IRA.
EPA is currently developing guidance CODcerning the Land Disposal Restrictions (LDR). While guidance
is limited. the Army has DOt, at this time, made I determination that any materials subject to LDR will be
present in the iD.f1uent treated or soil removed by this IRA. More listiDis are sd1eduled to be completed .
prior to the implementation of this IRA and the Army will rC"iew these as they are released. U it is
determined that a restricted disposal waste is present. the Army will act in a manner coasi.stent with EP A
guidance then in effect (or the maJlaiement of such within the contCXI of CERClA actions.
Soil removal (rom the area will be performed in acccrdance with the proc.cdures set (orth in the Task No.
32 Tcc.hnic:al PWI, Sampling Waste HandliD& (November 1987), and EPA's July 12. 1985, memorandum
regarding "EP A- Rcgion vm Proc.edure for H~dliD& of Materials frOID Drilling. Trench E:ccavation and
()ea)DtaminatioD duriD3 CERCl.A RIfFS Operations at the Rocky Mountain Arsenal.. While DO( an
ARAR, EPA's July 12. 1985 guidance memorandum applies to this action as a TBC. Soils geDcrated by
aavatioD during the course of this IRA. either at surface or subsurface, may be returned to the locatioD
Crom which they originated (i.c~ WI out. firu in). A1Jy materials remaiAing after completion of backfilling
that are suspected of being CODtaminated (ba.sed on field saeeai.ag tcc.hniques) will be properly stored.
sampled. analyz.cd. and ultimately disposed as CERClA hazardous wastes, as appropriate.
Hazardous waste resulting Cram CODSU'Uction Ktivitics. will be iDan.aged in accordanc.c with substantive
Resource Coascrvation and RCCOYery Act (RCRA) provisions. These s~antive provisions include but are
DO( limited (0: 40 CFR Part 262 (Subpart C, Pre- Tramport Rcquiremenu), 40 CFR part 263 (Tramporter
Standards), 40 CFR Part 264 (Subpart 1, CaataiDu Stonge and Subpart L. Waste Piles) and any more
s&riD3ent substantive provisions of comparable stale regulations contaiDcd in 6 CO .1007-3. The specific:
substantive standards applied will be determined by the facNa1 c:irc:umSUDCCS of the ac:cumulatioD, storage
or disposal tcchDiques acrually applied (0 any such material
As part of this IRA. some structures and remains of SUUCNrCS will be remOYed. rcsultiDg in debris. The
Army will analyze this material to determine whether it is ha%Mdous or subject to aay rcstridioDS conc.crning
disposal. 1D m:lln:tg;ng and disposing of this material, the Army will act coasistent with the EPA guidance
tbcD ill effect c:onc.crning such. material generated CD CERClA sites. Material determined to be hazardous
wiD be managed and disposed of as discussed aboYe.
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8.4.2.6 Operation of Tr~3tm~tlt SV5t~m
As descneed in ScaiOD 6.0 of this documeDt, the propolCd treatmeat system will provide sigDific:.ant air
poUUtiOD coDtrols including a packed scrubber colWDII &ad aaivated carboD adsorber.
The Army bas ideatified the requirements of 40 CFR S 264.343 conc.eraing the removal of organics as
relevaDt aDd appropriate to apply as a performaace standard for this IRA system. This requirement is Dot
applicable because it specific:.aUy ~pplies oaly to inc:iDeraton. In substantive fulfillment of this requiremeDt,
the IRA treatmeDt S)'5tem will be CODStrUC%ed to prOYidc 99.99% desuuctiOD aad removal of organics. as
caJcuJated from the total in the soil before treatmeDt throUib the venting of treated air to the atmosphere.
The complete pr~ss will be designed to auai4 this requirement.
The reguJatioDS coDta1ned in 40 CFR Parts 60 and 61, and the comparable State reguJatioDS were reviewed
to determine whether aDY ac:tioD-specific requirements were either applicable or relevaDt and appropriate
to apply to this IRA treatment system. Chemic:a1-specilic determiDatioDS are disaw.ed in SeaiOD 8.2. above.
The processes disaw.ed in those reguJatioDS were DOC coasidcred sufficieDtly similar to the ID Situ
ViuificatioD pr~s.s to make any actioD-spec:ific prCYisioa relevaa.t aild appropriate to apply to this IRA.
For example"Subparts F, I, Na and 000 of Put 61 were recommeDded for review by EPA in tbeir
commeDts OD the Proposed DecisioD Document. These Subparts were reviewed aDd (ound to address very
specific pr~s.scs and to CODta1n varying standards. indic:ati.ag that the standards were developed specific::illy
Cor the pr~sses identified aDd were DO( appropria1e to apply to Olher pr~s.s.ts which are DO( eXtremely
similar to the identified pr~s.s. The primary focus of these provisioDS is OD particulate emwioDS and
opacity. The Army has ideDtified a particulate emLWoD standard (or this IRA of 0.08 grams per dry staDdard
cubic (00( based OD the inc:i.neratioD staadard, U DOted in ScctiOD 8.2. above. The Army coDSiders the
opacity staDdard coDta1ned in Colorado Air PoUutioD CoDuol ReguJatioD No. 1. ScaiOD n, as relevant aDd
appropriate to apply to this IRA. Accordi.a.gly, the emissioDS Crom this IRA treatment system will DO( exc.eed
20% opacity.
8.2;4.7 Man:urement of Vitrifi~d Soil
The viuified soil will remaiD. peDding determiDatiOll of 5D.a1 remedial actioD in the ROD for the OD Post
Operable Uait. Dwing this period, the CIIezWve EZl(iangerment.A~~u"'ent and Feasibility Study processes
underway for the OD Post Operable UDit will be used to evaluate the aced for aad type of further actioD
appropriate (or the vitrified soil. These pr~ will address most of the matten contai4ed in 40 CFR Part
264, Subpart X. The Army will comply with the substantive requirements of 40 CFR 5 5 264.15, 264.33,
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264.7S and 264. i7 during the period oC management of the vitrified soil while rmaJ remedial action is
undergoing development.
The Army will comply with the substantive requirement3 oC 40 CFR ! 264.97 in conducting groundwater
monitoring in the area of the M-1 Sea.l.Lng Basins in order to moairor the effectiveness oC the vitrification
. .
process and determine any impacts on area groundwater from the vitrified mas.s..
8.4.28 Soil Treatment and Disoo~
These proposed remedUJ actions do nO( include the pouibiliry COf.oGIir~Ot-offsite dispOiW of.soils,debris--
or contaminated material e~vated pursuant to this IRA. excepc those that may be gcncrated Crom thc
construCtion activities dis.cus.sed above.
8.S COMPUANCE WITH nIE 0"rnER. ENVIRONMENTAL LAWS
As is evident Crom the various portions oC this document. this IRA was prcpared in subsuntive compliance
with 40 CFR l.S02.16 (the rcgulations implemcnting the Nation.a1 Enviroamental Policy Act oC 1969).
(~lo.Jt) (WI~) c=lrt{90)
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9.0
SCHEDULE .
The Craft ImpJemeDtation DocumeDt is scheduled for completion on 28 December 1990. The coDSUUaion
schedule will be contained in the Craft ImpJemeDWion DocumeDt for this Interim RespoDSe AaiOD (IRA).
This milestone bas beeD developed based upon the rmal A~~u"'eDt DocumeDt aDd the assumption that DO
dispute resolution will oc.c:ur. If C\'CD1S that necessitare I schedule change or c::aeDSion oc.c:ur, the change will
be incorporated in accordance with the Federal Facility A3feemeDt.
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10.0
CONSISTENCY wrm TIlE FINAL REMEDIAL ACI10N
The Federal Faciliry Agreement States that all Interim Response Actions (IRAs) shall °to the maximum eXtent
pracricabJe, be coa.si.stent with aDd contribute to the efficicnt performance of Fu1al Rcsponse Actionso
(paragraph 22.5).
Thc altcrnatives a.s.ses.sment aitCN (WCC 1989) werc used to evaluatc thc altcrnauves. Thc ~Iccted
alternative, by providing sig:nific.ant interim remediauon of a source of contamination, will be consistent with
any Fmal Response ACtion.
C~lo.:J!I) (W1.IClJRA) CCUlI9f'J1O) (1U4A)
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REFERENCES
D. P. ~es. IDe. 1986. Oczober. Rocky MOUDWD Anea.a1, Geohydrology Chemica1 Data: 1979-1985,
Volume 5 (Scdioas 34-36).
RMA CaLI Base. Augu.sIl].. 1989.
Eba.sco Services. Ine. 1988. Sepcember. rm.aJ P1wc I Data PrCSCDtaUOD Report, Army Spill Sites. South
PbAu ManuUauriDg Complcz. Task No. 2A, VenWa 3.2. RlC 88286R10.
GeoS~e Corp. 1989. 31 AUiUSL Treatabiliry Tcu Report ror Applic:atiOD oCID Situ ViuificauOD TecbDology
to Pesticide-, Arsenic., aDd Mcrc:ury-Coaf"If'PIin2ted Soils from the M-l PODds Sitc o( Roc:.ky MOUDtaia
Anea.a1, Colorado.
Woodwud-C1yde Conswtants. 1989a. r1Ul AlIeru.ative .Aj.~uft'lent o( Interim Response Actions for Other
Coftf21'P1in2riOQ Sourc.cs M-1 SenliD.g Basias.
Woodwvd-Oyde Conswtants. 1989b. rm.aJ Results 01 Field aDd Uboratory Inve.uigauons Conduaed to
Evaluate IDIcrim Response Actioas for Other Conf2min2fiOQ Sources.
..
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APPENDIX A
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION vm\
999 18th STREET - SUITE 500
DENVER, COLORADO 80202-2405
0~
Ref:
8HWM-SR
DEC :. 7 1~j
. Mr. Donala L. Campbell
Office of the Program Manager
Rocky Mountain Arsenal
ATTN: AMXRM-PM
Commerce City, Colorado 80022-2180
Re: Rocky Mountain Arsenal (RMA)
Proposed Decision Document tor
the Interim Response Action at
the M-1 Settling Basins, November
1989.
Dear Mr. Campbell:
We have reviewed the above referenced report and have the
enclosed comments. We have several major concerns. 'tiith the
~~tus of this IRA. These include, but are not limited to: the
...~ to carefully evaluate the potential of dewatering as a cost-
e~ective approach to assist the implementation ot the in-situ
vitrification process; the depth to which the process will reach;
the selection of air ARARsi the need for a risk analysis on any
emissions from around the hood, and further air pollution control
devices to ensure protection ot human health and the environment;
the need for selection of an ARAR as a performance standard for
the operation of ~he hoodi the need tor a monitoring system for
both air and groundwateri the need to specify the fate and ARARs
for structures now on a portion of the M-1 Basins; and the
potential need for further testing ot the selected process. We
encourage discussion 'tiith the RMA parties before preparation of
the next version ot the Decision Document.
Extensive revisions to address our concerns may result in a
need to reissue the Proposed Decision Document or otherwise
modify the schedule for the Draft Final Decision Document.
Please contact Linda Jacobson at (303) 294-7093, if you have
questions on this matter.
Sincerely,
~)~
Connally ~arf5
EPA Coordinator for RMA
Cleanup
Enclosure
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cc:
Col. Oan Voss, RMA-PMO
J. O. Smith, RMA-?MO
Jeff Edson, COB
Oavid Shelton, COB
Brad Beckham, COB-Air
John Clouse, COB-Air
Vicky Peters, CAGO
Lt. Col. Scott Isaacson
Chris Hahn, Shell
George Role, Shell
Robert Foster, OOJ
-
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Comment!:
Response:
Comment 2:
Response:
Comment 3:
Response:
'... ..
REC;PONSE TO COMMENTS ~OM THE'EPA
ON THE PROPOSED DECISTON DOCUMENT
FOR THE M-l SETTLING BASIN~
NOVEMBER ~
The grouadwater elevation has becD estimated OD rtgUte 2-2, yet the satUrated thickness of
alluvium with seasonal variatioDS, which affects several alternative actioDS, is not discussed.
The text has beeD revised to d.iscuss this point (Section 2.0). Figure 2-2 has beeD revised. The
grouadwater elevations have beeD re=oved since they are not relevant to the location map.
The subsurface barrier (or the -Slurry WaJJ and Cap. alternative would extend about five feet
into the Denver Formation; whereas. the slurry wall (or the in situ vitrification (T5\1) would
extend only CWo (eet into the Denver Formation. This difference should be explained.
The subsurface barrier (or in situ vitrification is intCDded to serve only as a temporary hydraulic
barrier during the ISV pr~ rather than as a contaminant containment system. The Proposed
Dec:isjon Document stated that the subsurface barrier would be constructed to 1.S feet below
grouad surface. However, because of comments Crom the EPA and the State, the Army aas
agreed to construct the subsurface barrier for the ISV alternative to be keyed into the Denver
Formation. The contact berween the Denver Formation and the alluvium is berween 11 and 19
feet below grouad surface in this area. Exact installation depth for the subsurface barrier will .
be determined during design.
SectioD 4.9, ConclusioDS, the text does aot mention the requirement for a slurry wall for the In-
Situ Vitrification Alternative. Sectioa 4.6, la-Situ Vitrification. and Sectioa 6.0, Summary of the
Interim Response Action. do aot d.iscuss the reasons for a slurry wall. The slurry waJJ has at
least tWo benefits. which should be mentioaed in the tat: 1) it provides a barrier for dewatering
the: mass to be vitrified (dewatering is usU.1lly less expensive than removing the: water as steam
during vitrification) and 2) it provides a long term barrier against leaching of contaminants away
Crom the: virriiie:d mass.
Subsection 4.6 and Section 6.0 both d.iscuss the fact tlw the: subsurface barrier is constructed to
temporary hydraulic barrier to isolate the: site: from the surrouading aquifer. Subsection 4.9
discusses the: reasons ISV is the preferred altcruative and does not address specific
imple:mentation steps for this alternative..
Dewatering is aor anticipated to be a~«~ry for this alternative.. The: vitrification process
produces an inert glass. It is nor ne.t"~u2ry to provide a long-term barrier because cont:uni"anu
will not leach Crom this glass. A toxic characteristic Ie:ach procedure (Ta.P) test was performed
on the vitrified soil using the: grind and sieve method rather than the: monolith method. The: glass
(2IQa.6IO) (1D/)lfIIO) (1iP A.Ml)
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Comment 4:
" Respoase:
Comment 5:
Response:
Comment 6:
Response:
Comment 7:
.
."\
passed the TCLP test for both arsenic and mercury, which are the more difficult metals to
immobilize (GeoSafe Corp. 1989).
The cost of melting a unit weight of soil is approximately equal to the cost of removing the same
unit weight oC water as steam; therefore, the installation of the slurry wall in combination with
dewatering weUs. possibly with some blind wells or "wiebe through the sludge may be the most
ecoaomica1 dcsigD. U dewatering is used. the water wilt require treatment; however, iC the slurry
trench is properly installed and keyed adequately into the Denver Formation. the Watet requiring
treatment wilt be mi"i",i7~d. The dewatering option should be carefully evaluated before release
oC the Draft FInal Decision Document., especWJy since the depth of coDtaminatioD c=ends into
the saturated zone.
The melt will be maintained to a minimum depth equal to the bottom of the sludge matcri:1l.
If the groundwatcr table exisu below the bottom of the sludge matcrial dwing operation, the mclt
may be allowed to alent to a maximum depth equal to the groundwatcr table elevation. Tbc
Army docs not intend to attempt to vitrify saturated soils bencath the M-I Settllilg Basia.s.,' nor
does it intend to dcwater the aquifer for purposes of vitrifyiag soils beneath the M-I Settllilg
Basins. The cxac:z depth of the melt will be determined dwing the design and implementation
oC this IRA.
rmal design of any slurry trench at this site should be based on a few additional geotcclWcal
borings with continuous sampling aa-oss the Dcnver Formation contac:z in combination with
cone penetration tesu (correlated to the borings) along the alignment of the wall to accurately
establish the penetration requiremenu of the slurry wall into the Denver Formation.
These recommendations will be considered during the design of this IRA.
The Decision Document docs DO( spec:iCy the depth to wb.ich the M-I Settling Basis will be
vitrified under the preferred alternative. The Decision Document needs to specify that
vitrification will be performed to a depth below the depth of mown contamination. U all the
contaminanu were DOC vitrified, the resulu would be a glass cap over the contaminated soils.
which is not acceptable since it would nO( be consistent with a final cleanup remedy, since it
would leave a continued source of COQr:.min"tion basica1Jy iJJacc.cssible to further remediation.
A sound scenario must be developed to ensure the source of contaminanu will be remediated.
The text has been revised to specify that vitrification will be performed at least to the bottom
oC the basins. U the groundwater uble is below the bottom oC the basins, the melt may extend
to a maximum depth equal to the groundwater table elevation. The cxac:z depth wilt be
determined during the design &ad implementation oC this IRA.
The preferred altcmative oC In-Situ Vitrification has aspects which are simiIar to inc:i.neration
altcmatives. AI such. the Decision Documcm Deeds to specify the actions to be taken to prevent
emissions of organics or metals to the atmosphere. The Decision Document should specify the
~IO) (CD/~,1a) (1!PA.WI)
-------
-
Respoasc::
UJmmeDt 8:
Respoasc::
Commcm 9:.
" Rcspoase:
~ ..
. desttuajOD and removal efficiencies to be achieved duriag the implemeDtatioD of the preferred
alteraative.
The quantity o( mercury that may be emitted &om the ~udge c:.ould be as great as 40 tODS,
although tha1 reprcscau lcsa than 0.5% of the sludge mass (page 2"17 of the Alternatives
~-.-eDt). The DecisioD Documc= should address the vaporizatioD and c:.ondeasatioD of
avaiIable mercury aDd arsenic (there is apparently 700 tODS of arsenic in the ~udge). whether
or DOt the existi.Dg-desiga ofTgas coDuol system caD handle the estimated quantities and whether
or DOt estimated quantities should be considered ~aces- (OD page 6-1, third paragrap~ the text
desaibes them as "trace c:.oDt:n.,.'n~ntl-, while the (ourth paragraph says they will be -elevated").
There should be =ensive iDformatioD aDd operating requiremeDts OD the hood performance
specified to ensure that the c:.oDt2""n~nts arc captUred through the system and do Dot escape
&om U'ouud the hood, ete. The per!OtmaDce of the hood should be analyzed for the abiliry to.
c:.omply with opaciry, VOCl, NESHAPs. ete. ARMS. There should be a risk analysis performed
regarding any escaping c:.oDtamiDanu from the hood aDd the air poUutiOD c:.oDUO! devices so
health-based emissioDS limiu caD be derived. (See specific ARA1U c:.ommeDts below.)
The Army agrees that these issues arc imporwu aDd will Deed to be addressed during the design
phase o( this IRA. However, these issues do DOC preclude the selectioD of ISV as the preferred
ahcnwive at this site.
A risk &Da.Iysis (or the pr~set involved in this IRA will be performed.
The proposed site remedy, iD-situ vitrification. is likely to be at least a sigaificaat part of the
permanent remedy (or the M-1 Senling Basins themselves (but Dot the resulting plume). The
public shouJd be made aware o( that. This is a source desttuajOD and immobilizatioD alternative
which docs DOC address the existiDg plume, bUt if employed would reduce the poteDtial of further
grouudwater impac:u.
ISV will result in de:suoyiD; the COftt2""n_nts in the M-l Settling Basins or permanently
immobilizing CODf2""rulntl in aD iAert glasa. The ww Onpou Rec:.ord o( DecisioD (ROD) will
determine whether this iDcrt g1asa C3D be le£t in place aDd considered a ~ remedy (or the M-
1 ~liftg Basins. or wtwher some I~Ai(;~&I aaioa is required. Groundwarer c:.oDtamiDatiOD will
be addressed in the fiDa1 ROD.
The 6DaI Record of DecisioD will ~ to addreu the Army's plans (or the vitrified mass alter
completioD of the acticm.
Agreed.
Commcm 10: The DeciSioa Document Deeds to establish . comprehensive monitoring program (or both air
aDd sroUDdwater emissions, the objectivcl of which indude the (ollowing:
(3IIW1I) (fIJ/2AIW) (lPAMI)
-------
Response:
Comment 11:
Response:
Comment 12:
what 10Dg-term re.wictions (instituuonal conuols) may have to be placed on the viuified
mass;
whether the IRA action is indeed a final action;
whether the IRA is operating suca:ssful1y;
whether there is any c:ha.age or impact to regioaa1 groundwater flow.
Such issues will have to be decided in the final Record oC Decision and revisited during the
mandatory post-~OD five-year reviews, as well
. The groundwater and air monitoring program will be establisbed during the design of this IRA.
The objcaives suggested by the EP A will be taken into considerauon at that time. The Army
agrees that these issues will be revisited during the mandatory post-ROD five.year reviews.
Re~ult~ of Field and Laboratorv Inve~till3tioM Conducted for the Remedi:1tioD of Other
Contamination Sourcc:s fRA~. November, 1989, stated there arc currently SUUdurc:s located on
the M.l Settling Basins. No otber informauon was presented on this Cad in other docUmentS
on this IRA. It is nc~"~s~ry to fully d.i.s.c1w these structures and their ueatment relative to the
ISV process. The AltARs reg:uding the Ueatment of these suuaures must appe:u in tbe
subsequent decision document.
The sUUctures reCerred to include scvcrallarge tanks in a cona-ete bermed area on tbe east basin.
These structures will be relocated before implemezu.auon of the ISV process The Draft Final
Decision Document was revised to disaw relocauon of these SUUcturc:s (Section 6.0). Specific
procedures Cor relocation will be pan of the implemezu.auon document- The ARARs regarding
these structures arc tii.KUSscd in the revised Decision Document.
In conclusion, ISV technology is c:W.sified by EP A as aD izmovauve technology: one that bas
been developed to large-scale and is ready for commercial deployment. but Cor which there is
not a significant commerc:iaJ experience base. It is necessary to thoroughly evaluate all aspectS
of ISV applicability for a specific site prior to commitment to large-scale operation. Geosafe
recommends that trcatability testing be performed u an imporu.at pan of the applicability
evaluation. The objccUvcs of the treaubilicy testing include generation oC specific operational
performance data needed to support operating parametcn/c:.ompliance efforts and generating
of data to support community relatioDS efforts. DepcndiJ2g on the resuJu of the ucatabiliry
tcsriD& Gcosafe may detcnainc that demonsuation testing is also. advisable.
The RMA partics need to discuss the potential oC further ucatability testing and demonsuation
testing to determine emis.sioDS oC arsenic aDd mercury aDd to revise the risk analysis oC this
cleanup altcnwive Cor the M.l basins. .
(3IIW1C1) (aI/181'O) (IIP.un)
-------
Response:
---
\
Two treatabiliry tests have been succcssfulIy performed on the M-l Settling Basins sludge. .
Results of these tests have been di.scu.ss.c.d with and distributed to the Organizations and the State.
Resulu show that ISV is an effcaive ttcatmcnt proa:s.s for the M-l Settling Basins sludge.
The Army has agreed to perform a demonstration tcst immediately prior to implementation. The
Army will keep the Organizations and the State informed during this additional testing.
SPECIFlC COMMENTS
Comment 1:
Response:
Comment 2;
P.8-1 Depending on what is later to be done with the vitrified mass. there are pos.sible standardS
. in 40 ~ Part 264. including Subpart X. that c:ould be utilized for monitoring or analysis of the
process.
Additionally. there is DO spec:i1ic dewatering scenario set for the in the di.s~on. Due to the
presence of arsenic:. the dewatered liquids could be bandled by the CERClJ\ Wastewater
Treatment System.
Condensate from the hood of tbe in situ vitrifiation ueatment system and any other liquids
generated by this IRA will be bandled by the CERClA Wastewater TreatmeDt System.
P. 8-3 We disagree with the statement that there are DO air ARARs.. NESHAP levels for
arsenic and mercury are "relc85% c:ontroL The approximate quantity of arsenic to be dealt with by the ISV
operation is approximately 1.400.(0) Ib/yr. Assuming 90% is retained in the melt, potential
emissions are approximately 14O,(XX) Ib/yr. To reduce these e~ons below 900 Ib/yr, >99%
s
-------
Response:
Comment 3:
R~ponse:
Comment 4:
Response:
Commcnt 5:
.,
control efficiency would be nccessary. Control efficiency and melt retention of arsenic: should
be discus.sed in the documents.
Since thc NESHAP rcgulations are conc:crncd with these levels of emissions. onc might apec:t
that greater emis.sion levels of arsenic and mercury might threatcn public: health in thc area.
ne ISV cJe.anup of thc M.l basins has poccmia1 (or such emis.sions and yet these were not
considered ill the selution pr~ A risk analysis of the air emissions should be considered
ill the selection of the cleanup alternative to ensurc all emissions limitations protec:r human
health and the e1Mroament. .
The arsenic: NESHAPS (or glass manufaauring is idcntified as relevant and appropriate in thc
Fusal Decision Document. The State stand.vd. outlined in 5 CCR 1007.3 Regulation 8 for
mercury is also identi1ied as relevant and appropriate.
P. 8-3, fltst paragraph. this paragraph sc.cms to be a 1>oilerplatc" statement. It is not ac:c:urate
with regard to NMQS applying to AU Qualiry Control Regions wl1ic:h are dissimilar to this IRA
area. and with regard to appliC4biliry to largc air masses. See previously agreed to language
(or past J:RAs.
This seaion has becn revised to rc11ca the Army's detcrmination that NMQS standards arc
ncither appliC4ble nor relevant and appropriate to apply to a specific: emWions source such as
this treatment system. .
P. 8-3, 2nd paragraph. Assuming that thc 40 CFR Pans 60 and 61 regulations were developed
to prcvcnt ambient air concentrations of mercury and arsenic: (thereby to protec:r public: health),
these ambient concentration sund.vds need to be reanalyzed as potentia! ARARs. The
appropriate baclcground documenu Deed to be revicwed to determine thc mcrcury and arsenic:
concentrations which may have becn thc goals behind these regulations.
Thc CERCLA Compliance with Other uws Manual (EPA/S40G.S/OO9) on pages 2.5 and 2-6
list NESHAP emis.sion rates (or mercury and arsenic:. These rates, while appliC4ble to mcrcury
smclters, c:hJoralk.1li planu. sewage sludge incinerators/dryers or glass manufac:numg, show a
conceru by EP A (or emissions of mcrcury aDd arsenic:. Potentia! emissions Crom the ISY
remediation could be far greater than these NESHAP emission rates and therefore may have the
potential (or ~"'~~~~i~g the goal ambicm coac:cntrations behind the NESHAP regulations. The
NESHAPS rates should be selcacd as rcJcvw IDd appropriate stand.vds (or the ISV proc:.css,
unless beath;.based stand.vds arc morc SU'ingcnt.
See response to £lA's Specific Commem No. 2.
Page 8-4 The report docs aot recognize that emissions Crom the iii-sitU vitrification process
could be subjca to "Action-Specific ARAJU". The rcport di.scus.scs consuuaion type cmis.sions
and ignores emissions resulting from the operation of the vitrification process.
(8IW10) ('111/)11'0) (EPA.Wl)
-------
Response:
Comment 6:
Response:
Comment 7:
. pense:
. . .. --
The rmal Decision Document addresses emis.s.ions from the operation of the in situ vitrific::ltion
process under action-specific: AR.AR.s. This information can be Cound in the Operation of
Treatment System Section of the Action-Specific ARARs. Chemic:al-specific: ARARs are also
scleaed. See Response to EPA's Specific Comment No. 2.
Page &4, Section 8.4, AJ1 ARAR(s) needs to be selected in the Draft rmal Decision Document
that will be the standard of performance (or the capture efficiency of the hood. The parties
need to discuss as potential ARAR.s: the AOCR Regulation No.!, Section n. Smoke and
Opacity, and EP A's Ne Source Performance Standards (or relevant and appropriate subpartS.
such as NSPS, Part 60, Subpart 1. Hoc Mix Aspha1~ 6O.9'2(a)2; Subpart F, Portland Cement,
60.62(b) (2); and Part 60, Subpart Na, Standards of Performance Cor Secondary Emissions Crom
Basic: Oxygen Process Steel-making. 6O.142(a)(1), fugitive emis.s.ion Control, 10% opacity, and
Subpart 000, Standards of Performance for Nonmetallic Mineral Processing Plants.
The rU1al Decision Document addresses ~ for the capture efficiency of the IRA treatment
system.
Page 8-5, seaJnd paragraph. this c::mned sutement may be appropriate (or the construction
phase of this IRA. However, it is irrelevant to the operation of the pr~ since the proc:ess
canaot be shut down quickly and involves bcatiDg of soils, not installati.on of wells.
This paragrapb oaly addresses tbe construction pbase of this IRA and the related exavation of
material and is contained in tbat section of the document. The treatment system will be designed
to prevent the emission ~f 99.99 percent of the orgmics in the ground at the beginning of the
treatment process. Air pollution controls include a pac:.ked saubber column and activated carbon
absorber.
7
-------
Shell Oil Company
December 19. 1989
Office of the Program Manager for Rocky Mountain
ATTN: AMXR~M, Mr. Donald~. Campbell
Rocky Mountain Arsenal, Building 111
Commerce City, Colorado 80022-2180
Dear Mr. Campbell:
Arsenal
~
Or'le Shell Fla:a
F 0 Boa 4J20
t'40uston. Tellis ;'7210
Enclosed herewith are Shell Oil's comments on the Proposed Decision
Document for the Interim Response Action at the M-l Settling Basins,
November. 1989. Version 2.0. Shell's comments on ARAR's are being
sent under seoarate cover. .
incerely,
f2-~~4J
R. D~~l
Manager Technical
Denver Site Project
/ajg
Enclosure
cc:
(w/enclosure)
Office of the Program Manager for Rocky
ATTN: AMXRM-PM: Col. Daniel R. Voss
Bldg. E-4460
Aberdeen Proving Ground. MD 21010-5401
Office of the Program Manager for Rocky Mountain
ATTN: AMXRM-RP: Mr. Kevin T. Blose
Rocky Mountain Arsenal, Building 111
Commerce City, CO 80022-2180
Arsena 1
Mountain Arsenal
Office of the Program Manager for Rocky
ATTN: AMXRM-IA: Mr, Bruce M. Huenefeld
Rocky Mcu~tain Arsenal. Building 111
Commerce City, CO 80022-2180
Mountain Arsenal
~ .1' ~
Q'''I_1?''''~--
.~...-
~ I ~
-------
cc: Mr. Eradley S. Bridgewater
Department of Justice
c/o Acumenics Research & Technology
999 18th Street
Suite SOl, North Tower
Denver, CO 80202
Department of the Army
Environmental Litigation Branch
Pentagon Room IC480
ATTN: DAJA-ELL: Major Lawrence
Washington, DC 20310-2210
E. Rouse
Victoria L. Peters, ESQ.
Assistant Attorney General
CERCLA Litigation Section
1560 Broadway, Suite 250
Denver, CO 80202
Mr. Robert L. Duprey
Director, Hazardous Waste Management Division
U.S. Environmental Protection Agency, Region VIII
One Denver Place
999 18th Street, Suite 500
Denver, CO 80202-2405
Mr. Connally Mears, 8HWM-SR
EPA Coordinator for Rocky Mountain Arsenal
US EPA, Region VIII, Superfund
999 18th Street, Denver Place, Suite 500
Denver, CO 80202-2405
Mr. Thomas P. Looby
Assistant Director
Colorado Cepartment of Health
4210 East 11th Avenue
Denver, CO 80220
Mr. Jeff Edson
Hazardous Materials and Waste Management
Colorado Department of Health
4210 East 11th Avenue
Denver, CO 80220
-------
"
.
REsPONSE TO CO~ ~OM ~, On. COMPANX
ON PROPOSED DECISION I>OCtJMF:N'I
FOR nIE INrFRTM RF~PONSE AcnO~
AT THE M-t SF:MUNG BASIN~
VERsION 2.0.
NO'VE'ARER ~
GENERAJ- COMMENr
Comment 1:
In Shell's opinion, d.u~ prcsczued in the rec.cntly Wue4 repon1dcscn"bing 1989 laboratory
and field investigations of [be M-1 Settling BaWls fail to validate [be undocumented
c.onclusion used by the Army in preparing [bc Alteru~tivc Assessmcnt [bat this site i.s an
aCtive source of u~nic c.onUmwuonl. Al[bough elevated c.oncentrations of u~nic were
deteaed in wells immediately dowugradicDC of bo[b [bc M-1 and Lime Settling Basins.
arsenic c.oaceatrations dccliac very rapidly shon distances downgradient of lhesc wells.
Since [bcse basins have aisted since 1942, [be data suggest that u~nic. in [be fona pre~at
in [bc baWls is relatively immobilc. Studiesl in [be literatUre OD u~nic mobilicy suppan
that cenaia inorganic species of arsenic ue csscatiaUy immobile in soil.
Even it [be M-1 Basins ue coas.idered an aCtive source, because of [be very slow movement
of u~nic it seems unlikely that a 10118 tcrm tcduUc.a1 or aJS( beaefit would be gained by
c.oaduaia3 an interim respoase KriOD at this ~tc. Shcll urges [bc Army to reconsider
whc[bcr any aCtioD Wer thaa Monitoriag/Maintcnance would be appropriate, Lc., is tbc
~tc an aCtive source and. it so, spccifiQUy wtut beaefic(s) would be e:rpeacd (rom an
intcrim respoase aCtioa? Purs\WJt to the Decision Aow Chart, Monitoring/Maintenance
is the appropri~te aCtiOD it ei[bcr .[be sile is aoc an aCtive primary source, data ue
iludequatc to detcr'D1U1e whethcr it is an aCtive source, or [bcre is ao clear ideatifiable
bencw Crom coaduaia3 an i.aterim respoase aaioa. '
Nocwithstandiag the above, SheU has [bc (ollowing c.ommeats OD the evaluation of
aheruatives as prcsczued Ua the Proposed DecisioD Document.
Although i.a-sicu vitrificatiOD may be ID applicable techaology (or I remcdiaJ respoase aCtioa
II this ~te. SheD belie-..es that. based OD Federal Facility Agreement IDd CERClA
guideliaes. the Slurry Wall with ~p Iltcnwive is clearly the bettcr choice of the tWo (or
18Results of Ficldand Laboratory Investigations cODducted (or the RcmediatioD of Other CoDt2ft'1in:lfiOD Sources
IDterim Respoase ACtiOD November, 1989, VersiOD 2.0. This report, which was issued c.oncurreDtly (November
27, 1989( with the Proposed DecisioD DocumeDt, prCSCDts srudies OD wbich the Army c.oacluded in [be
Al1emative A.s.R""~alcZU Documczu tJw this sile is ID aaive soure=.
ShcU's c.ommcnu, dated December 19, 1989, to D. 1.. campbeU. OD the repon listed i.a (oocnoce No. 1.
(11111c:m...1C1D)(C'OtoOaHft.SHL)(CIIIZ71'O)
-------
.
Respoase:
aa iatenm response action. it more than moDitoring/maintenance berweeD the tWo is
dumed a~.
The Slurry Wall with Cap aJternative fully satisfies the IRA objective of mirigatiag the
release of CODtamUww Crom this site. Thus.. it is protective or humaa health aad the
aMrOameDL The other threshold c:ri.reria. compliaDce with ARARs. .should aot be a
problem because of the relative simplicity of. and experieDce with. the technologies iavolved.
It SCOlCS much higher than the la-situ V11rific:ation altei-aative OD implemeDtabilicy with
~pecz both to timiag aDd casc of imp1emezuatioa. Slurry Wall with Cap also scores hi;her
OIl shon-term effectiveDess because of much lower po(eatial for emWioas and DO residual
treatmeDt wa.stes.
A major cost compoaeat of Slurry Wall with Cap it the slurry wall. which is a common
elemeDt ia both alternatives. Thus.. a major portiOD of the cost of this alternative is
compatible with ia-situ vitrification or other technology aJteruatives requirins a slurry wall
it they were applied to this site II a final respoase actioa.
SheU eDcourages CODtinUed developmeDt of ia-situ vitrification for possible application to
this aDd other RMA sites. It belie-..es., however, that implemeDtatioD of this technology ia
the f'nmework of an IRA at the M-l Settling BasiDs ia u.anea:ssary since the Slurry Wall
with Cap alteruative meetS the IRA objective and guidelines., is compatible with possible
future use of ia-sicu vitrification technology, and at less than a fifth of' the estimated cost
(with substantially greater upside cost risk associated with ia-situ VitrificatiOD). Furtber,
c:arryiag the ia-situ vitrification technology forward ia the FS, rather than as aD IRA. will .
easure consisteacy with fuW respease aaioas (e.g.. will the block of vitrified residue be
compacjble with other respoase ~oas and with !&ad use?). ID additioD this technology,
which has aot yet beeD applied commerc:ia1Jy, eDtails po(eDUaJ riskS which dearly could be
bener managed ia the coateXI of the fia.aJ remedy. These riW relate to po(eatW emis.sioas
from the work site and dOWDSUeam emWioD coauol systems and the residual wastes
produced.
.
SheU bdieva that because of these poteDtial riW and limited commerc:ia1 apc:rieDce with
this technology, implemenuUon of the in-situ vitrification alteruative would eDtail
subct:llui.2l1y greater time and COlt th&a eavisioacd by the Prop0sc4 DecisiOD DocumeDt.
Based OD available data, the M.t Scn1iDg BasiDs appear to be aa active source of arsenic:
conf.2lnin.2UOD to the groundwater. The Army agrcca that the arsenic appears to be
aneDuating rapidly. However the M.t Scn1iDg Basins are a highly CODceatratc.d, weU-
defiDed area of CODf.2lnift.2fiOD. The grouadwatcr table appareaUy iatenecu this
CODtamiDatiOD during pans of the year. There is a beaefit in performing aD IRA at this site
to elilnin.2fe the coataa of the groUDdwater with this highly CODt:amift.2tc4 source. There
is also a beaefit in performing treatmeat instead of coDtainmeDt because the area is weU.
derIDed. aDd the treatmeDt process cho5cD for this IRA ia oae of the f'ew appropriate
treatment proc~~~ for the combinatioD of coatamiDants at this site (high conceDuatioas
.
(1tIUc:az..1C11)(~)(Cll/21~
-------
of metals, peSticides in surface soils. and the possible presence of Army agents or agent
degradation products). .
The Army acknowledges that the slurry wall and cap alternative would meet the objective
of mitigating the release, and be easier and less c:.ostly to implement. However. ISV will also
satisfy technology investigation objectives ot the Feasibility Srudy. Although not required
by the Federal Facility Agreement. the Army is choosing to coordiAate the .bot spotS. IRA
with the Feasibility Srudy. Several pocential benefits of this coordination exist. which the
Army believes justify the additioaaJ COSlS. Primarily. the benefits the Army sees are
poccntiaJ applic.arion at Other sites and the potential that ISV otthe M-l Settliag Bam might
be considered a finaJ remedy by the 6.aa1 Onpost ROD. For this reason and the reasons
stated above. the Army is committed to pursuing the design and implementation of ISV as
the IRA for the M-l Settliag Basi.as.
ISV will result in permanently immobilizing the contaminaa.ts in the M-l Scttliag Basins in
an inen glus. The Record of Decision (ROD) will determine whether this iDen glass c.aa
be left in place and considered a final remedy for the M-l Scttliag Basins. or wbether some
adclitioaaJ action is required. .
SPECIF1C COMMENTS
Commcnt 1:
Response:
Comment 2;
Response:
Pl.Ile 1.1. r1t$t paragrapb.
In the WI sentcnce. the time period betWeen 1947. a..nd 1982 applies to the manufaauring
period. not the lease period.
The teD bas been changed.
PJ.lZe 2-4. WI paragrapb.
Shell Oil Company is a signatory ot the Federal Facility Agreement.
"The Fedcn1 Facility Agreement s~es 13 Interim Response Actions (IRA's)
determined to be ~U.:lry and appropriate..
However, for the Remediation of Other Conf2fftin:arion Sourc:cs IRA. the Federal Faciliry
Agreement SUtcs that "1"his action CODSisu ol .J~t"'ent and, as nec:e~u~- the selection
IDd implementation ol ID IRA for the . . . M-t Sett1i.ag Basins . . .. (Anide 22.1(1);
emphasis added).
The Army interpretS the FrA.s ~6.zUtion of aD IRA to be the process which consists ot
u-'-c"'ent and, u a~--"c..:a"Y, the selection and implemCDLation of an interim action.
Thcretorc, UKu"'ent ot the 13 IRAs is n~l"fOC.c..:ary. but implementation of an interim action
mayor may aO( be n~~""2ry, as determined by the useu"'ent for this site.
(11111~ICID)(~)(aZ/%1~
-------
CommeIU 3:
Response:
Comment 4:
Respoase:
Comment S:
Respoase:
Comment 6:
Response:
The Army conduaed Ihe IRA Alternatives Assessment o( Ihe M-l Settling Basins and has
determined that Ihe interim aaion alternalive chosen (or implementalion is Dec:.cs.sary and
appropriate.
P~e 4-1. 40 {DteM Resoonse Action Alternatives.
. Alrernatives
Although long-term effeaivenes5 is leu imponazu (or an interim respoase action lhaD (or
I fiDaJ respoase action. this aiterion seems ro rec.eive major empha.s.is in Ihese summaries.
whereas shon-term effectiveness (e.g.. impaa OD workers &ad Ihc communiry) is hardly
meationed.
The t= has been changed to provide a more bal.u1c:.cd summary o( Ihe detailed evaluatioD
presented in Ihe IRA Alternalives A~~u""ent (or Ihe M-l Seuling Basins (WCC 1989a).
Pallc 4-2. 4 oS SIuTr-I Wall ..v;th CaD.
The mulUJayered cap described (or inhibiting surlac:.c infiltration is (ar more complex Ihan
is n~~"'-~ry (or shon-term use. A CODtOUted. low-perme.abiliry layer o( clay plus a vegetative
cover would subslaatialJy reduc:.c infiluali,?D.
The cap described in this seaion is (or evalualioD purposes oaly. - The Army agrees Ihat a
less complex cap may be appropriate (or this sjte. up specificatioDS would be considered
further in Ihe desigD and implemeDl.1tioa pbase o( this IRA if this alternalive was chosen.
Paae 4-3. 46 In-situ Vitrifkatioa
-nus is a technically (e.a.sible alternative that destroys Ihe organic contaminants. . ..
Some organics will be carried away in Ihe off'gas. and Iheir (ate will depend aD Ihe
dowastream coDuol technologies employed.
The oB'gas tre.aUDeztt system will be dcsigued to capnue and address any organic
coatamiaants DO( destroyed by the ISV proc:.es.s.
Pae 4-4. 4.9 ConclusioM.
As discu.s.s.ed UDder General Comment.\, oa the basis of results of the 1989 field a.nd
laboratory ~ifP'rioas, the AnDy should rccoa.sider the MoaitoriDgfMainteDaDc:.c
akcnwM.
See respoase to SheD's Genera! CommeIU No. 1.
(11111CIIWI8)(~)(az/:f""
-------
Comment 7:
Response:
Comment 8:
Respoa.se:
Comment 9:
Response:
.
. .
Page ~.l. 5.0 Chro[lolo~ of Even~.
Reference to the report issued OD 1989 field iDvestig.ations should be iDcluded iD this
chroDology.
The CAtry (or Febnwy 1988 should be deleted. because it is oUtSide the process prescribed
by the FFA. See paragraph 12.7 of the FFA. U the eauy is to be rerained. a dare should
be provided (or the request, so t1w the Organizations may verify thar such a request was
iD (aa made. The March 7, 1989 letter from David L. AaderSOD to Edward J. McGrath
iDcludes a summary of the SUNs o( various requests (or ARAR identifications. bw does aot
. meDtioD any request iD c.onneetioD with this IRA.
The texx has been changed to iDclude reference to the field and laboratory report. The entry
(or Febnwy 1988 has been deleted.
Page 6-1. first paragraph.
See speci1ic c.ommenu 3 and 5.
See responses to SbeU's Speciljc Comment Nos. 3 and 5.
Page 6-1. 5UOad paragraph.
SiDce the c.ontamiDarioa mae exxeads below the groUDdwarer table, wouldn't a dewatering
Slep be required? U so, tr~tmeat and dispos.aJ of groUDdwarer would be aCCCMary.
"MOS( o( the arsenic and the other merals will be iDc.orporated iDro the gJas.s. All of
the mercury and possibly so~e arsenic will be vaporized and subsequeauy c.oadeased
m the offgas treatmeat system."
These nwo sentences are c.oauadiaory with res~ to mercury. Based OD the relatively
high volatility of mQSl arsenic c.ompoUDds. VOlatilizatiOD o( the arsenic present is possible.
DeterminatioD of arsenic (ate should be a key objective of the tr~tability srudy.
The mcIr will be maiat.aiaed to a minimum depth equal to the bonom o( the sludge material.
U the gr'OUDdwater table cxisu below the bonom of the sludge marerW during operations.
the melt may be allowed to a maximum depth equal to. the groUDdwter ~Ie elevation. The
Army docs DOC wend to anempc to Yiuify sarutared soils beneath the M-l Senliag Basins
aor does it mrend to dewarer the aquifer (or pW'pOSel of vitrifymg soil beneadl the M.l
ScttJiq Basias. The aacz depth of the melt will be determined during the dcsiga and
impIemcftticioa of this IRA.
The teu bas been cha.aged to stare that "mOSt of the arsenic and the heavy metals will be
mcorporated iDto the glass. MOSt of the mercury and some o( the arsenic will be vaporized
" Determination of arsenic (ate was a key objCClive of the treatability srudy.
(Ulll~ICIO)(C'OWW!:Hft.sHL)(=/Z71'JO)
-------
Comment 10: P~e 6-1. third paragrapb.
In addition to toxic: metals., it should be nQ(ed that the sludge, soil and groundwater iD and
Dear the M.l Basins contaiD some Ai&.bJx oderiIerous compounds. The abilicy o( a vacuum
. hood with redundancy to col1SW1dy capnue ~ntiaUv aU o( the off'gas would need to be
carefully coasidercd.
.
Why is a glycol system (or condensing off'gas specified at this time? Why is iDdirect
condensation spec:Wed at this time (versus. (or aample, quench cooLiDg)? These
spec:Wcations are wmcas.wy at this time and should be left (or design decisions.
Response:
The vacuum hood will be dcs.iped to capcure esseD1ia1.ly aU of the off. gas. The glycol
cooLiDg system is a standard iDtegraJ part o( the proprietary process. Indirea condensation
was referenc:.ed s.inc.c it was the control method used during treatabilicy testing. However,
otber methods can be reviewed during desip.
Comment 11: P:l2e 6-1. (ourth paragraph.
.AIly sludge generated iD the wastewater treatment will be added to unvitrified
sou/sludge (or subSequent' .,;trUicatioD..
It is wme«~ury and., s.inc.c the wastewater treatment will be determined during pilot testing.
premanue to make this statement. For aample. if constituenu iD the recyded sludge
partition strongly to the ofTgas. they will merely rccyde.
TrcatmeDC and disposal o( scrubber efl1ucnt would also have to be dealt with during design.
Response:
This SUtement W becn removed Crom the tc:a. Treatment and disposal o( scrubber
efl1ucDC will be addzcsscd during dc.sigD.
CommeDC 12:
P3.!lC 7.1.
Paragraphs 2. &ad 3. should be elimiAated. because they do DC)( apply to the M.l portion
01 the 8Hoc Spou. IRA.
Responsc:
Tb.csc paragraphs have been d.c:letcd.
Comment 13: P~ 1.1. paragraph 4.
To conform to paragrapb Z2.1 of the FFA. replace -rhe AnDy, SbeIJ. and State are given
the oppommicy to identify, On a prelimin:ary basis. 8 with '"The Organizations and DOl shall
have the oppommicy to participate, at the RMA Committee level. in the identification and
selection of..
6
-------
Response:
Tbe texz has 'been changed.
Comment 14: Page 8.2. fifth paragraph.
., . . this interim response aCtioD., which is DOC inteaded to be . . , a fmaJ response actioa
.
. . .
.
In.situ vitrificatioa should be c:oasidered gA1x it such treatment caD reasonably be
ezpe.cted to coa.stirure the fi.aal response aCtioD (or this site. It. would be very difficult
aDd c:ostJy to coDdua a further remedW actioa 012 I luge block o( embedded vitrified
soill sludge.
In addiooD to arsc~* and mercury, some organic compoUDds would also be preseat in liquid
~~~ . .
Response:
It would be pouJole to consider ISV a fuW remedy. However, the final dispositioa o( [be
vitrified soil/sludge will be determined by the Oapou Rec.ord of Decisioa (ROD),
Comment 1.S: P:llle 8-3. SCaJad paragraph.
In the pnuJtimate line of this paragraph. Section J should probably be B.;!.
Response:
Tbe tar bas been changed.
Comment 17: P:tlle 8.4, l.asr paragraph.
~e CODSUuc:tiOD ~( aD in.situ vitrificatiOD system docs DOC iavolve signilic:aat
excavatiOD in the area 011 the M-l BuiDs, providUlg very little poceatiaJ (or the
gener.uioD o( air emissions during construCtioa.,
lIwallatioa of a slurry wall arOUDd this site. as proposed in the in-siru vitrificatioa alternative,
will inYOlve subu~tiaJ acavatioa into COnt~",inJlted soil
Respoa.se:
The Army disagrees r1w the coDSUUaioa of the subsurface barrier bas the pocenUaJ to result
in significant air cmiuioaa Which could DOC be adequately moDitored aDd coatroUed through
the Hc.a1th aDd ~ery Piau (or this IRA as is ocbet CODStrUctioa aaivity. The 1W'r0w
aava1ioa av-~ry (or mu~natioa oil barrier is very UD1ikeJy to result in large amOUDts
of soil being ~ in I maaaer which wou1d cause YO~ti)i~cjoa of compoUDds which may
be pn:scar in those soils.
.
Comment 18: P~ to-t.r lase SCDteacc-
See commeat 6.
Response:
See response to Shell's GeneraJ Comment No.1.
(11111aa...1GD)(~)(allrtfWl)
-------
Comment ~
Response:
Comment:
Response:
.
'\
JlF~PONSES TO COMMENTS FROM SHEil. On. COMPANY
ON THE APPUCABLE OR RELEVANT AND APPROPRIATE
REOUIREMENt'S FOR THE RFMFDIATION OF 011{ER
CONTAMINATION SOURCES l'M-l SE'M1..ING BASINS)
INTERIM JlF~PONSE AcnON
~
SheU disagrees that the MC-s for arsenic and mercury are relevant and appropriate and
apply at the point of discharge of treated liquid effluent. Iu stated by the Army, tre3tment
utiliz.ed by or constructed for this IRA will Dot provide drinking water and will Dot be a
public water system. Further, this IRA is not intended to be a comprehensive groundwater
remedial aaion or final response aaioD. MCL.s. wbich are intended to protect drinking
water at the tap, are irrelevant to this IRA. Nevertheless, SheU docs Dot object to the
concentratioD levels identified as AR.AR levels ad operational criteria.
The Final Decision Document reflects that liquids generated by this IRA trC3tment system
will be treated by the CERClJ\ Wastewater Treatment System.
SheU questions wby the Army cites Regu1.1tion 3, Seaion IV(D)(3)(a) as relevant and
appropriate. The Army provides DO dis~OD of wbich, or why, the PSD requiremects
are relevant and appropriate.
Tbe Final Decision Document bas been revised in response to this comment.
"
(11111c:m..ICID)(c::owwmn'UHL)(a:t(38{f1t)
-------
I
-------
\
Mr. campbell
Rocky Mountain Arsenal
December 27, 1989
Page 2
If you have questions
please feel free to call me.
etf Edson
RMA project Manager
Hazardous Materials and
Waste Management Division
J'TE: jrnb
C:\WS2000\~~\C~~PBELJ.LTR
Enclosures
cc:
Michael Hope, Esq.
John Moscato, Esq.
Chris Hahn, Shell
Edward J. McGrath, Esq.
Connally Mears, EPA
Bruce Ray, EPA
Major LawrenceE. Rouse
Tony Truschel, GeoTrans
or wish to discuss
these
lssues,
~
-------
.
RESPONSE TO COMMENT'S FROM THE STATE OF COLORADO
ON THE PROPOSED DECISION DOCUMENT
FOR 011-IER CONTAMINATION SOURCES IRA
M-l SETI'UNG BASINS
GENERAL COMMENT'S
Comment 1:
Rcspol1SC:
Comment 2:
Respol1SC:
~
The ~y bas e%prcs.sed its relucunce to trcaI grouadwatcr contamination from the M-l
SeriliDg Basins. However, Arsenic cont2mifl2tion remains a problem. As the State has
previously and repeatedly werted, the Army should aplore the possibility o( treating inorganic.s.
if DO( immcdately dOViD-gradient o( the M-l Settling Basins. then at the Basin A neck.
The Army acknowledges wt grouadwa&u~area--is-conumiuted-wilh-both organics and
iDorganic:s. However, grouadwater treatment is nO( withiD the scope of this IRA. The treatment
proa:ss for Basin A Neck is DO( pan of this IRA specifically, and comments on the operation
of tbe Basin A Neck s~tem should be referred to Wt IRA.
In the Treatability Test Report for Application of In SitU Vitrification Technology to Pc:sticidc:-,
Arsenic-, aDd Merc:ury-QJDUmUwed Soils from the M-l Ponds Site of Rocky Mouatain
ArsenaJ., Colorado (Treatability Document), Table" aDd the Addendum show that a mus
baJuce calculated the results of the pilO( test indicates a 37% deficit of arsenic, and it ~%
deficit of merc:ury. In the Addendum it was bypotbcsiz.cd that the missing arsenic and. aJtbo~
DO( explicitly mentioned. the mWing mcrc:ury was in the melt. Ac.cording to the explanation
offered. the amouats of these metals in tbe melt were UDdercstimated because the coDc:.cntralioD
of these metals varied aaosa the melt. U the melt is DO( bomogeneous then the degree of
vamuon should be a.sc:.crtained through Idditional wnplcs of the pilot test melt. so that (1) it
caD be determined if this caD reasonably ac.cowu for the mWing metals aDd (2) TCLP tcsu an
be repeated on enough different piec:.cs of the melt of the M-l Basins during impleme:ntation
to insure: that the results are: reprcscntative of the enUre me:lt.
Geosafe bas becn conducting (ollow-up analytical work in aD ane:mp( to reduc:.c the mus baJanc:.c
deficits (or me:rc:ury aDd arsenic reported in the refe:renc:.cd document.
Then: arc seYC1'al areas where ugJ'ilit"2f1( KCW'acy margins werc or could have been inuoduc:.cd
duriDg test pre:paration:
.
SIudllc Volume
The sludge was placed in the tcsI container COnCUlTCDt with the plac:.cment o( the
surrouading soils. All open-ended squ.are cardboard box was utiliz.ed to segregate the:
sludge Crom the surrouading soils during the plac:.cment process.. Once the sludge and
soil bad bee1i placed. the box wu withdrawn. leaving a square column o( sludge
surrounded by soil. During waste placement. the eledrodcs occupied the inside corne:rs
of the boz. Geosaie neglecte:d to subuact the volume occupied by the eledrodcs before:
~IO) (G/:7fW/1 (!!'A11tWI)
-------
(8II.41G) (tlllZ7f'11111 (SfAmwl)
calculating the total mass o( the sludge (based upoa density and volume). In additioD.,
the volume betWeea the electrodes and the corners o( the box was observed to be empty
during waste placemeat. By subtracting these volumes from the amount o( waste
reponed to be placed. the taul amount o( mercury and arsenic: preseat in the test
coatainer prior to the test was less than that whic.h was used to calculate mass balances
ill the report.
.
SIud2e De~i(y
The dry deasiry o( the lime sludge &om the site was provided to G~e prior to the
test and was wumed to be 1.1 g/cm'. Beause o( the naCUfe o( the sl~dge. the dry
density o( the Wasle is vamble. It was DOCed in the field that, after the sludge was
cxavated and placed in a drum. senlin3 was observed. If a sample were takea of sludge
whic.h b.ad settled. the dry den.sicy (based upoa the wet volume) would be higher than
that (or sludge whic.h b.ad DO( settled.
Whea G~e plac:.ed the sludge into the test coatainer at its facility in Seattle. it was
moved with a smalJ trowel The acE of moving the sludge in this manner slurried the
sludge and probably resulted in a dry density (based upoa wet volume) whic.h was lower
than that (or the wasle prior to. being disturbed. U the densicy o( the sludge in the test
coataiDer was lower than 1.1 g/cm'. the Det effect o(this phenomenon would mean that
there was lesa mercury and arsenic preseDl in the test coatainer prior to the test (ban
that which was reponed. Geosale believes that this was the case.
.
Ar~enic: Conc:entrarioa i.n Glass
The resuJlS o( the aewoa aaivation analysis (NAA) showed that arsenic coaceatrations
varied Crom apprcmmately 400 ppm to 1345 ppm. Since the glass samples were
coUected Crom the cenual ponion oC the gWs monolith, it is reasonable to as.sume that
there was g1.a.s.s in the moaolith with arsenic coacenuations greater than and less than
the measured amounts. It is pr~le that, IS bubbles (whic.h coDLaiDed vaporized
arsenic) rose in the melt, thevaporizcd arsenic in the gas bubbles was absorbed by the
melt on its way to the surfaa:. Duriq the test, bubbles were seen to reside Deat the
surface alter risi.q through the mea ad . &cxhy layer of glasl was observed in the
upper ponion of the solidified moaolith. Based upon these obsemtioas, it is possible
that I higher arsenic co~ ia prCSCDt near the top of the monolith.
Cieosate will SOOn be coDduaiq UO«lIer ueaubility tcst on soils conr2lftift2ted with
anenic. ID this tea czzeasiYe borizoma1 and vertical sampling will be performed to
determiDe it there is any pre(erc2Uia1 conccntration of arsenic in the monolith. They
will aaCZDpI to pia permission to share the results of this tcst with the Army.
3
-------
New ~cu1ations. wllich take into ac.couat the corrc.ded sotatting volume of sludge and a Dew
assumed dry deosicy of 0.9 g/cm reduce the mass balance deficiu for arsenic to 14% and
mercury to 34.7%.
.
.
AD additional area wbere systematic accuracy ranges could have bad an influence during
placement of the sludge, was in the measurement of the sludge volume. Minor irregularities
CD the soils surface upon which the sludge was placed and minor irregularities on the surface
of the sludge when itS depth was measured could have resulted in a sludge volume which was
less than that which was measured. U thiI margin of error was oaly 0.25 in.. the effc.d would
be to reduce the mas.s balance deficit for arsenic to 3% and reduce the mercury deficit to 30%.
These mas.s balance figures are low ~DOUgh to ac.couat for other apcc:ted systematic accuracy
ranges which could occur throughouc the treaUbilicy test process (such as measurement of offga.s
flow volume).
The analytical results from the carboa aDd the de.s.ic.cant used in the test show low
concentrations of mercury. This is what was expeaed. U high concentrations of mercury were
fouad in these me~ then the offgas ~pliq ac:.curacy would be. open to question. With the
low concentrations of mercury fouad in the carboa and de.s.ic.cant. GeosaCe believes that the
offgas sampliq procedures were valid.
The results of aD energy dispersive spcaroscopy (EDS) analysis showed that mercury clid Dot
amalgamate with the sotainles.s stc.eJ offgas pipes.
The X.ray diffractioa an.aJysis performed oa the sludge. which coUcaed in the coadea.sate tank
dW"iag the test, showed that anenic triolide was present. Several experts ~~mifted the
diffraaograms and determined that mercury compounds were DOC present at detectioa limits.
Mercury is a liquid (and therefore amorpbous) a.t room temperature and X.ray diffractioa is
noc capable of detcaing amorphous materials. This would suggest that mercury found in the
sludge (using cold vapor atomic ahsorptjoa) ia in the elemental stage.
c
In summary, GeoSale bas continued effo~ to reduce the mas.s balance deficits for mercury and
aneaic reported after the treatabilicy tc:st.i.ag of the M.l Settling Basins sludge. Several areas
haw heeD ideDtified where sigzWicam ac:.curac:y margins were or could have beea introduced
during test preparariOD, which could affect the masa balaDc:e. ID additioD, GeoSale will sooa
be conducting another treatabilicy test oa arsenic coar:lmin.2red soils, and will perform ateasive
borizonw and vertical sampling to determiDe if there is any preferential coacewatioD of arsenic
ill the monolith. F"uWJy, a fuU.saJe ISV demoDSU2tion test will be performed prior to
implemc:nwion to alleviate swc c:.oac:ems.
.
CommeDt 3:
Results of the Toxic:iry Charaaeristic t ~_hiftg Procedure (TCLP) were shown for oDly mercury
aDd arsenic. The TCLP should be fUll on samples of the melt Crom the M-1 test. with analyses
for aJJ of the other ccfttaJ7'ift2ftts which are lisred ill the proposed TCLP regulations and known
to be present ill the sludge or surrouadi.ag soil.
3
-------
Response:
CommCDI 4:
Respoasc:
.
Mercury and arsenic are among the most difficult metals to fix. It is assumed thar.. if these
clements are sucas.sful1y fix.ed. wer iDorganics would be ~ eYeD more efficicntly. Virtually
all organics are destroyed iD the approximately 1700. C temperaNre of the melL Thc balance
would be vaporized aDd collcaed ill the offgas treatment system.
.
IDc:iDeraton operating at temperatures as high as those (ouad in the melt are significant sources
01 NOx. The interior o( the melt is probably. reduciDg esavUoament but the boc surface of tbe
melt. exposed to oxygen in the ambient air (the stack gases were found to contain 20.9% o~gen)
may be the source of NOx emWioDS. Additionally, the air a.boYe the melt may be boc enough
to oxidize the atmospberic nitrogen. La response to earlier State questions on NOx emission
(Dca:mber, 1989) it was stated that previous ISV testing had resulted Us DOn-detCdable NOx
e~oDS. However, because iDcomplete c:iwions were giv=. it was DOC pouible for the State
to determine if operating condiuons during these tCSU were comparable to those proposed for
the ISV of the M-l Settling Basins. Specilica1Jy, (1) were these testS done with the same large
amount of ex.ccsI air fIowing through the hood aDd over the melt?, aDd (2) was the air above
the melt during the testS maintained at a similar temperature to what is apec:ted during the ISV
of the Basins'1
It is true that iDciDeraton are QgJ'ifiant sources of NOx. This is beause Large volumes of
air are beated to mamnum pr()t"..ui"B temperatures aDd maiDtaiDed at these temperatures for
sigDilic:ant periods of time. During ISV, the ouIy pba: wbere air an be exposed to
temperatures sufficient for produaioa of NOx is within I few ccntimeten of the melt. During
smaU- aDd Large.sca1e pro«ui,,& the melt is c:oYered with a ccnmic insulating bW1kct which
lfti"irni7'" beat IosL T1Us bWlket is several iAc.bcs thick.
It was correcJy stated that condiLions iD the melt are suongJy reducing aDd the NOx is reduced
to N2 and 02" While it is pouible that NOx could be produced at the surface of the melt. the
very small regi01l (wben compared to iDc:incra.ton) at which this could take place, the high fIow-
through of cxc=s air, the iAbibited air mobility at the mch surface aDd the reduced beat loss
resulting from the insulating bWlkca all c:oauibwe to inhibited NOx production. The result is
NOx c:oDcenuaUons consistently below dacction limits.
The chemistry 01 the \V&SIe bciDg mched wi11 daermiAc the melt temperature, IDd hence, the
tcmpencure of the air aboYe the melt. In the large-scale tese cited in the rcpo~ soils Crom the
HaAlord site were melted. These soiIa bYe Si02 coDCl:DUUions of &boUi 65%. The RMA
waste (COft.icli"B of. mimue of soil aDd sJud8e) bas Si02 COIIcentnUOllS which are c:.oasidcrably
Icsa IDd bas I hiP (20% to 30%) caJcium ~DtralioL "The c:alcium adS II a fIux fOl' the melt
aad results in . lower mell tcmpenrurc tJwa tba& from teus conducted 011 Hanford soil AI
. result. the temperature 01 the air above the mell in the RMA projcc:l ia cxpcded to be lower
tIwI tba& (or the tCSl conducted 011 HaAlord soil. The bulk hood temperature for the M-l
projcc:l ia ~ac4 to be 150 degreca c=1igradc.
>
.
. The tun-scale tests conducted on Hanford soil were done with roughly twice the volume of air
Bow-through as that which is anticipated (or tun-scale operations at the RMA site.
(8Do41t) (f4/rr,." (7I'A1UU)
-------
ommeDt 5:
.
.
Response:
mmeDt 6:
.
..
Respoase:
A major concern in the dcsigD of the ISV system should be the capability of the hood to
withstand the (orc:.cs that may OCCW' during operation. A tear in the hood would result in the
dangerous emiuion of untreated organics and volatile metals and metal compounds. Even if
the elccuic power to the melt were immediately cut off, the melt would emit bazardous
substances for several hours while cooling. Is there a back. up to the hood? Is there a chance
for hoc-spots ill the melt th.a1 might superheat small areas of the hood or the possibility that
large bubbles of hot gases might pressuriz.c the hood? Is there a chance of flames? ISV is a
reJatjyeJy unproven techDology aDd we be1ie..-e th.a1 a wge measure of redundancy ill the design
of the hood or other safety precautioas is required to "'1ni"'171" the risks Crom unforeseen events
which could poteD1ial1y compromise the hood's intcgity. The State also believes some rypc of
emergency response plan 5hould be prepared to ass.i.st ill respondin3 to t¥s rypc of event.
The hood i.s a steel supersuuaure with a high temperacure fibergJas.s skin. The (orc:.cs required
to damage this hood would likely come Crom the pressure inaea.\C iWOciated with contact
betWeen the melt aDd a drum of flammable liquid. However, the site history and field
iDvestigatioas at this site do not iDdicate th.a1 aDY drums would be encountered. The hood i.s
operated under negative pressure. The system will be designed with redundant vacuum blowers
u weU as sundby elcarica1 powe1' generation capability (or the offg.a.s treatment system.
AJI emergency response plan will be prepared aDd delivered with the Implementation Document.
This plan will be tied iDto the RMA emergency response plaa.
The offgas treatment bas been loosely described iD the Proposed Decision Document. Properly
dcsigDed it should be capable of effectively d~"nin~ the efDuent gases. The pilot plant report
indicates that ooJy aldrin, dieldrin, mercury aDd 3nCniC were monitored iD the offgascs. In the .
pyrolysis proc:.ess wge organic molecules are first broken dowa iDto smaller organic molecules
before final molecular decomposition. Thus the: low levels iD the offga.\CS of the: high molecular
weight pesticides. aldriD aDd dieldrin, c:anDOC be interpreted to mc:an that all organics have been
destroyed to the same c.xEenL
Proper design will include consideration of the presence of other contaminants, Le.. smaller, less
easily absorbed (on carbon) orgaaic:s IDd the presence of other metals, iDcludin3 cadmium.
~dmium is present ill the slud3e a& conCCDUa.UoDS of up to 3900 ug/g ac:.c:ordin3 to Table 2-
1 in the F'mal Al1cnwivea A.1Ku-eDL 10 a reuDt paper by Buelt (1989) the ratio of the
cadmium originally in the waste to the amount ewlved from the soil (as a gas) in alSV pilot
tcst was between 3 IDd .. to 1. i.e. m to 25% 01 the cadmium present in the treated soil was
traDSlerre.d into the offgascs.
Buell. J.1- 1989. ~o1ten..(j1asa Pr~,",. in Freeman. H.M.. cd.. Standard Handbook of
Huudo~ Waste Tre3fment and Dis~ McGraw-Hill.
The priDc:ipals aff'cctiog the behavior o( organie vapon during ISV are such that they are drawn
into the melt and experieoa: temperarures equivalent to melt temperatures. No mowa organic
material c:u survive these temperatures (1600 to 2000 degrees centigrade) which means that
5
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Comment 7:
Respoa.sc:
\ .
aU organic material exposed to these temperarures are converted to their atomic or diatomic
Corm such as hydrogen. carbon. and c:hJoriae. There is a possibilicy that organic materials coula
escape destruction during start-up it they were at or very neat the surface. These materials
are effectively c:apnued in the scrubber IDd/or the activated carbon filter in the offgas system.
By coaduaiDg start-up in a la~r of c:Jcu soil oycrlyiDg the coatammated material, the poWbilicy
of rel~~cif'lg any orga.a.ic material to the ofrgas system is reduc.ed to neat zero. A detailed
disau&ioa of the behavior of organic materials is included in the Theoretical Discussion section
of the repon. .
.
..
In the cited mJormatioa: In Situ Vitrific:.3t.1on oC Tr3mura.n.ic: Waste: An Uod:lted S~tc:ms
Evaluation and ADDtic:.3tion.s ~e~ment. PNL-4800 Suppll, p. 57, shoW'S that the release of
cadmium in the wge-scaJe tCSl-wu-~ed .;t.ltgaseous~T!Usmeans that when large
YOlumes of gas were released to the off'gas system (as bubbles Crom the melt), the contaLaed
vaporized cadmium did Dot have a chaDce to be absorbed by the mclt before reaching the
surface. The wormation also shows th.a.c cadmium release was oower during periods when
gas was not being released in significant YOlumcs. In addition. the offgas system captures
substantially all o( the cadmium released Crom the melt aDd ccaceauates it in the scrub solution
which is filtered. The mters are then Pfnt'''''''Y'd in I s~ueDt melt to allow (or additional
absorptioa of cadmium. ~um is not released to the atmosphere. This caD be demoDSUated
with appropriate oifgas Ympling. Since large quantities of combustible material or other gas-
geaerating material is abseat of the M-1 waste., cadmium retentioa in the melt is C%pCded [0
be.
In the November 1989 Resulu of Field IDd Uboratory InVcstigatioDS Conduaed for the
Remc4iatioa 01 Other ContamUwioa Sources Interim Response Adion (M-1 Field Report),
the lhiwCSl o( the alluvium in the viciniry of the M-1 Basins was reported to vary from U feet
in the SOwhweslCt'D ccrner of the site., to 20 feet in the southcastenl corner (FtgW'e 2.2).
Therefore, the slurry wall completion depth. it keyed into the Deaver Formation. would also
vary across the site. The Army has indicated th.a.c the slurry waJJ would be ccuSuuded [0 a 15-
(00( depth (M-1"n~u",eDt Document. p. ~S), aDd that keying into the Deaver would noc be
n«~'I..C..2r'Y. However, this would result iD . maximum dewatering depth of 15 (eet. aDd allow
UDderOow to ccme iD .CCDUCI with the melt. The pouibiliry exists that during field
implemeDtation.. ic may be D"'~u..sry Co apply ISV cO depths greater thaa iDitia11y estimated.
Therc!ore, U I ~ measure, aDd to isolate the mell &om SurrOUDding groundwater,
the: slurry wall should be securety keyed wo the Deaver FormalioD.
The subsurface barrier (or iA situ vitrilicatioa ia intended Co sctYe oaJy as. temporary hydraulic
barrier. rather thaa a ccf'lr::a",if'l~f'lr ccf'lr::ai""'eDt system. Thia barrier wi1J isolate the material
ill the basins &om the surrounding aquifer duriq the: ISV proa:sa. HoweYCf. because of
comments &om the EP A aDd the SUte. the Azmy has agreed to coasuucr the subsurface barrier
Cor the ISV altcnwive co be keyed iDto the Denver FormatioD. The type of subsurface barrier.
either slurry wall or shed pilings. will be ddcrmiDcd duriq dfl'c'l.ig1'
,
-
(aD:WIG) (flUZtfWl) (ft'AftJ'U)
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Comment 8;
R~poasc:
.
.
Comment 9:
R~poDSC:
Comment 10:
RespoJUC:
.
4
Comment 11:
. ... , .
Because dewatering will be nc:cessary to lower the water table below the base.
the design of the dewatering system mUSl be included in the implementation
The melt will be maintained to a m.i.ui.mum depth equal to the bottom of the .
U the groundwater table ai.us beJow the bottom of the sludge material during
meJt may be aUowed to =tend to a maximum depth equal to the groundwater
The Army does noc intend to attempt to vitrify sacurated soils beneath the M.l
nor does it intend to dewater the aquifer for purposes of vitrifying soil beneath {
Basins. The CDC% depth will be determined during the desigD of this IRA.
In the lithologic descriptions presented by Woodward.Oyde for the eight so
showu in F'IgUrC "'2 (Section 4.U), depth to bottom of pits wcu not given for a
soil borings, SB Nos. 6. 7, or S. that were-c:omplctcawilluntlie M.l Settlli:
example, SB No.6 COnsisted of sands to a depth of 2 feet, sands and waste to
oaly from 2.6 to 6.5 feet, m~d sand and wcute &om 6.5 to 7 feet, and wet $;j
Where is the bottom of the pit located? How extensive is vertical migration 0
below bottom of pit? What contaminant concentrations were found with depc
do~ not list sample depths.) Since it is not clear wbere the bottoms of the pits a.
since there appears to be signi1!c:ant contamination beneath the pits, the ver
. contamination, including soils beneath the waste pits. The Army, therefc
underestimated the: depth and amount of material to be treated using ISV. Vc:
significant conUmination showd drive the scJc:aion of the depth of ISV treatmc
showd propose aitena (or de:termining the: depth of treatment based c
contamination8 in the: implementation document. These: aiteN showd be
additional site charaaeriz3tion may be: required it inadequate information is avo
The bottom of the M-l Settling Basins is approximately 7 (eet below ground sur
soil borings will be drilled and sampled during desigD to more clearly evaluate the
of contamiaatjoa. The vitrification will be performed to a depth at least to the I
basins. U the groundwater table is beJow the bottom of the basins, the melt mOl
maximum depth equal to the groundwater table elevation.
In the M-l "",~.:",= Document, the Army mentions that struaures are prCSCD!
areas ot the M-1 Basins (page 2-1). Which struc::ures are referenc:.cd and what is
the struc::ure (interms of contamination)? Wall thcsc: struc::ures be moved or rais
the ISV proc:.as?
The struc::ures referred to include several large tanks in a concrete berm cd area
basin. Thcsc: struc::ures will be relocated before implementation ot the ISV prace
ot the Draft F'1D3J Decision Document wcu revised to discuss relocation ot the:;
(Sc:aion 6.0). SpeQfic procedures will be pan ot the implementation document.
In the M-1 Field Document, SB No. 5 is leared outside (approximately 20 (eet Ie
ot the M-I Settling Basins (FIgUre 2-6). However, this boring had the high=t cor
~IO) (aI/18f11) ~A~J)
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. Respoasc:
CommeDt 12:
Response:
of the [Wo volatiles and (our of the five semivolatiles (ound in previous soil sampling programs
(Table 2.1). After review of the as-built drawings and aerial phexographs is the Boring SB No.
S incJud~ within the area of the M-l Basins? U nO(, further ch.araaerization of the soil
contaminatioD surrounding this boring wilJ be required during the (easibilicy srudy.
.
SB No. S is Ioc:at~ ouuidc the M-l Settling Basins, as shoWD 012 .FIgure 2~ of the M-l neld
Document. This IRA is inteDded to address the source material within the M-l SenliDg Basins.
Other soil coar:afftiqatioD in the SoUth Pb.Du area will be addressed by the Oapost ROD.
.
In the M-l DecisioD Document (page 6-1) the VOlume of water CODdea.scd in the offgas
treatmeDt system was csUmar~ to be 7OO,()X) gallons. (which includes a 1.5% contingeDCY). [a
making this csUmate it was assumed. crrODCOusJy, that the weigJu &Utioa of water in the sludge
wu equivaleDt to the volume (naioD. GiveD a sludge deasjcy o( 1.35 tons/ycf (as ~ated in the
rusaJ AlterDaUves ASY~~~eDt of [aterim Response Aaions (or Other CoDtamination Sourccs
M-l Settling Basins M-l A~~c:"'eDt Document), the aauaJ amount of condensate geDerated
by the ISV of 6400 ycf of sludge would be 980,()X) gallons. or I.U million gallons with a 15%
contingeDCY. (This is based 012 a sludge thickaes.s of five (eet. which may bave to be modified
based aD depth of significant coatamwtioa in soils beaeath the sludge.) For the design o(
the ISV system, the Army Deeds to modify the estimate of the volume of coadensate which will
be geDerated. .
. The volume estimates in the IRA Alteruatives A5-~u"'eDt were oaly used (or cou estimating.
More accurate water volume estimates would be caJc:uUt~ during design. ThC3C estimates will
depead 012 the depth of the melt.
SPECIFTC CO~
CommeDt 1:
Response:
CommeDt 2:
Response:
Comment 3:
Please indicate the locations of treDches M-lT.3, M-lT-5, and M-lT ~ 012 rJgW'e 4-2 of the M-
1 neld DocumeDt. AdditioaaUy, plca.sc indiCate wasle material/soils coataa aD all soil borings
and piu showa in the figure.
This commeDt will be tUcD into consideratioa during revisioa of the field and bboratory
~iptiOIl report.
The arsenic value (or Well 361.93 ia lisI~ 113920 ug/1 all page 4-1.5 ol the M-l neld DocumeDt,
ad 342D ug/1 in rJgW'e 4-3. Please correa this iac.oa.siueacy.
This iDconsisreDcy will be corrected duriag n:vWoli of the field aDd bborarory inYeStigatiOIl
report.
.
Lcgcads aDd UDiu should be prescated in Table 4-3, 4-4, 4-7, 4-8, 4-1~ and 4-u. Please
refereDce soil sample IDs in the same JDaADer ill the t= as ill the tables. AdditioaaUy, please
list sampling intervals (or all samples prC3Cnted in the tables.
.
(aa.u" (f!4!r1 /fill ('IfAftJoIJ)
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csponsc:
,
J
.
.
.'\
This comment will be takcn into coasideratioD during revision of the field and Laboratory
investigation report.
(~IO) (=171/90) (~A11!.WI)
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RF~PONSE TO COMMENT'S FROM THE STATE OF COLORADO
ON DRAFT APPLICABLE OR ~J:'T J:'VANi" AND APPROPRIATE REQUIREMENTS
FOR TIlE M-l SETTUNG BASINS
Im"ERIM RESPONSE AcnON
GENERAL COMMEm"S
.
Comment 1:
Response:
To the exzent that this document repeats tel contained in previous Army draft ARARs
documents witho1U acknowledging prior comments offered by the parties. the State refcrs the
Army to previous State ARAR.s comments.
Please see the Army's previous respol1SC$ to the State's comments.
SPECIFTC COMMENT'S
Comment 1:
Response:
Comment 2:
P. 8-~ para. 3: The Army statcs that -'The liquid effluent is to be trcatcd for arsenic and
merCW')', wlUch arc the contamma.ats cxpeac.d to remain with this effluent after completion of
offgas conuol process. 8 Nowbere in the proposed decision document does the Army list all
products of the offgas control process. However, in 8Response to Comments, State of Colorado
QUcsUon on M-l Basins, In Situ Vitrification (December 1989): the Army stated that thc
foUowmg contaminants were present in the offgas: dieldrin, aldrin. merCW')', carbon dioxid:,
oxygen. arsenic:, arsine g~ carbon monoxide and particulates. Although the Army claims tbat
treatment equipment will remove over 99 percent of particulates larger than 0.5 miaons and
0.3 miaons. and 99.9 percent of the volatile and semivolatile compounds, the Army should
include ARARs for all these cont:lmi":I"tS.
The Final Decision Document addresses, in greater detail. ARARs for tbe anticipated air
emis.sions (rom the in situ viuificatiozi process.
P. 8-2, para. 1: The Army statcs that consistent with the Proposed National Contingency Plan.
Maximum Contaminant Level Goals were not considered applicable, relevant or appropriate
to apply in the contexl of the treatment system.
However, CERa.A iuelI. regulatio~ (sic), requires that remedial actions at least achieve
MCLG's. Moreover, even the proposed NCP docs not categorically dismiss MCLG's as
ARAR's.
The CongrcssioaaJ coaferees who drafted S 121 or CERaA (wlUch was part or the 1986
CERa.A amendments) have been emphatic that CERaA remedial actions are to achieve
MCLG's as disrmguished Crom MCl.'s. A March rr. 1987 letter Crom United States
Representative Jamcs Aorio (and other committee coaferees) to Lee Thomas, (ormer EPA
Administrator, states:
.
.
C2IDo'IO) (\'11/311'0) (STA11LMI)
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,
R~poase:
fI
Comment 3:
~
" . ' .
-Yn auy circumstauces iD wlUth MCL's are relevant aud appropriate, MCLG's are
equally relevaut aud appropriate. Section Ul(d) (2) (A) states:
-Such remedial action shalJ require a,level o{ staudard of aJntrol wlUth at least attains
Maximum Contamiaaut LcveJ Goals established UDder the Safe Drinking Water Act
aad water quality aJntrol criteria are relevant aad appropriate UDder the circ:um.stauces
of the release or threatened release..
-rhe speciLic reference to MCLG's iD the law mak~ it clear that th~e particular
SlaDdards, where they are more striageat th.a.a the aJmparable MCL's, are the primary
SlaDcUrds that musz be attaiacd by Superfund cleanups of groUDdwater: .
-rhe reasoa the Congrw those to specify MCLG's is that UDder the Safe Drinking
Water Aa. the difference betWeen the tWo requirements c:aa be signific:aar. In
{ormulating MCL's the Agency aJzWders (ca.Ubiliry (aud ~pecially aJst) as well as
hcaJth-b~d faaors. MCL's coasequezuly may offer signiiic:aady Iw protection of
humau health aad the ezMrODmCDt than MCLG's..
A5 the cited statutory language rc:11ca.s, MCLGs are to be attained where thev are determineQ
relevant and aoorooriat~ (emphasis added). EPA. as the (ederal agency responsible for
implementing the statute., has issued the proposed NO' iD order to implement the statute,
EPA's stated policy, as cited in the propo,scd NCP is that MCI..s are generally relevant and
appropriate as cleanup staudards. While iDdividual members o( the (ederallegislature may have
expressed ,disagreement with EP A's interpretatioa of the statutory provision, this do~ not affect
the validiry o{ EPA regulatory guidauce. Individual federal and state legislators do sometimes
disagree with the implemezuatioa by (ederal and state agenci~ of particular statut~ U the
{ederal or Slate legislanue., as a body, determin~ that the implementation by the agency is not
wbat was,iDteaded by the legislanue, they may eDaa furtber legislation to clarify the statute or
rcdUea the agency. The cited EP A policy has been iD effea (or several ye31s and no legislative
aaion has been taken [0 require c:haagc.
The State also appears to overlook the (aa that this is an iDterim response aaion, not the fmal
r~ponse aaion. There is no legislative or EPA guidance whicl1 implies MCLGs should be
applied [0 sucl1 interim aaioDS whicl1 are ccaduaed iD advance o{ final response aaions. A5
the proposed NCP makes clear, site specific detcnni.aations can be made that establish different
cleanup criteria {or the spec::ilic site. The =cnsive RI/EA/FS process is designed to provide
the basis {or determining site spec:ilIc aiteria (or fiDaJ response aaions and that process is
underway 11 the Arsenal. f"'mal cleanup aitcria based Upon the RI/EA/FS proc.cs.s, will be
established (or the Arsenal ccDSi.u= with the. CERClA guidance developed by EP A.'
P. 8-3, para. 2: The Army SUtes that 40 c.F.R. S 61 was not cczWdered applicable, relevant
or appropriate to the IRA t:reatmenr system. However, 5 CCR 1007-3, regulation 8 lists
emissions standards for merc:ury whicl1 are applicable to .aU stationary sources whicl1 . . .
iDc:inerare or dry wastewater treatment plant sludge and' to any other source usmg mercury in
~IG) (ID/~,.." ('S1'A'mWI)
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Response:
CommeDt 4:
Response:
CommeDt 5:
Respoa.sc:
CommeDt 6:
Response:
any (orm.. Although the treatmeDt syste~')~s not ~y def1D.ition .use. mercury, the process is
sufficiently similar (or the emissioD suadard in regulatioD 8 to apply as a relevant and
appropriate requirement. ID addition. the reporting requirementS of 40 C.F.R. ~ 61 subpart P
(arsenic) should also be considered relevant and appropriate.
The ruW DecisioD Document ideatWes ARAR.s Cor air emissions Cor both arsenic and mercury,
idenWyiDg the Stale mercury standard..
.
P. 8-4, para. 6: The Army states that coasuuaion of an oD.site vitrification system does not
involve sigDific:ant acavatiOD in the area of the M.1 basins, with thereCore little potential Cor
air emissions during consuuaion. However, the proposed decisioD document states that the
system will include the coasuuaion of a slurry wall. wllich requires excavation. Therefore the
constructioD clearly has the potential Cor release of air emissions during construaion. The Army
should expand itS ARARs analysis to include S!andards Cor air emissions Crom the construction
o( the slurry wall.
. 1
The Army di.s.agrees that the COnsUUaiOD oC the subsurface barrier bas the potential to result
. in significant air emissions wllich could not be adequately monitored and controlled through the
Health and Safety Plan for this IRA as is other coasuuaion activity. The narrow excavation
necessary for installatiOD of a barrier is very unlikely to result in Large amountS oC soil being
exposed in a manner wllich would cause VOlatiJ..izatiOD oC compo\U1ds wllich may be present in
those soils.
P. 8-5, para. 1: The Army states Wt there ue no cational or state ambient air qualicy stan duds
applicable, relevant or appropriate for any oC the volatile or semivolatile c.hemic:a1.s in the.
groundwater in the M-1 area wbere consuuction is contemplated. However, methylene chloride,
a volatile organobalogeD compound. was Cound in the soil and/or sludge oC the M.1 basins. The
Army should therefore include 6 CCR 1007.3 regulation 7 in itS ARAR's analysis (or air
emissions due to treatment system construaion.
The Army reviewed 6 CCR 1007.3 and found no regulation #7. Methylene chloride is listed
in 5 CCR 1001.9 RegulatioD #7. However, in Sccion IIB (Excmptions), methylene chloride
is exempt Crom Regulation #7. Also see response to the State's Specific: Comment No.4.
P.8-5, pan. 4: The Army S!ates that the provisions of 40 c.F.R. 5 50.06 are considered relevant
and appropriate. Howcvcr, the Army must also consider Colorado RegulatioD ~ which regulates
all total suspended particulars (I'SP) and is therefore striaer than the federal S!andard. The
Army has also misslatcd the Cederal S!andard.. The correa federal standard is that the
partic:ulate matter must nOC exceed SO miaograms per cubic: meter, Dot 75, as the Army states.
The federal standard also li.u partic:ulate emission Cor a 24 hour average at ]j() miaograms per
cubic: meter. .
~
Fugitive partic:ulatc emissions requirements of Colorado Regulation 1 were considered. The
Azmy rec:ogniz.cs this requirement aDd will use best practical technology to minimize such
~IO) (CD"',.., (STA~l)
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.
Comment 7:
Response:
Comment 8:
Response:
J
t
''\
emissions. This,section has been revised to reflect the current standard in 40 CFR Part 50.6.
This document also includes the State's speci.6c: standard in Regulation No.1 (or construc:tion
activity.
P. 8-5, para. 3: The Army states that the standards (ound in 40 C.F.R. 5 61 (.NESHAPS.) werc
Dot considered applicable, relevant or appropriate. The Army should consider NESHAPS
reJcvaD1 and appropriate if the CODf2m1ft2ftts subject to NESHAPS are emitted in quantities
contemplated by the regulatioa.
NESHAPS arc proc:.csa specific and arc nO( considered relevant and appropriate to apply to any
treatment system unless such system is similar to the specific: process (or which that standard
was developed. The FmaJ Decision Document doc:.i reflect the determination o( an arsenic:
NESHAPS-mndarctforgIass-manufac:turing as relevant and appropriate to apply to this IRA
treatment system.
P. 8-10, para. 4: The Army states that the IRA was prcpared in substantive compliana: with
40 C.F. R. 5 l.S02.16, the regulations implementing the National Environmental Policy Act o(
1969. The Army must also be in compliana: with 32 C.F.R. pt. 651 which are Departmcnt of
Army regulations dealing specific:alJy with NEP A requirementS at CERClA sites.
The Army is proc:edin3 in ac:CDrwa: with the regulations contained in 32 CFR 651.
(~IO) (CII/)lf'O) (SfAT1LW1)
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