United Stales
Environmental Protection
Agency
Office ol
Emergency and
Remedial Response
EPA/ROD/R10 J5/007
October 1985
&EPA Superfund
Enforcement Decision Document
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TECHNICAL REPORT DATA
(Please reael Instructions on the fe"erse IHfol'e co,""lnf1KI
" REPORT NO, 12, 3, RECIPIENT'S ACCESSION NO,
EPA/ROD/R10-85/007
'. TITL.E AND SU8TITL.E ~, REPORT DATE
UPERFUND ENFORCEMENT DECISION DOCUMENT October 24, 1985
Queen City Farms, WA (IRM/EDD) &, PERFORMING ORGANIZATION CODE
7. AuTHORISI 8. PERFORMING ORGANIZATION REPORT NO,
e. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM E~EMENT NO.
", CONTRACT/GRANT NO
12. SPONSORING AGENCY NAME AND ADDRESS 13, TYPE OF REPORT ANO PERIOD COVERED
U.S. Environmental Protection Agency Final ROD Report
401 M Street, S. W. 1., SPONSORING AGENCY COOE
washington, D.C. 20460 800/00
15. SUPI"L.EMENTARY NOTES
-
HI. ABSTRACT
The Queen City Farms (QCF) site is a 320-acre parcel of land located approximately
2.5 miles north of the town of Maple Va lley in King County, Washington. The site
inc ludes a wooded area, a lake known as Queen City Lake, six industrial waste disposal
ponds, an airstrip, several residences, and a gravel pit. The six ponds on the site
'o/ere used for the disposal of industrial wastes from approximately 1955 to 1964.
cause of the time pe riod, few records exist regarding the exact types of wastes taken
_0 the site. Howeve r, in 1980 six waste ponds were sampled by EPA contractors. The
analyses of water, sludge, and sediment samples identified the presence of 44 priority
pollutants. Some of the contaminants found were: chromium, lead, PCB s, acids, volatile
organics, toluene and trichloroethylene (TCE).
The recommended Initial Remedial Measure is to be carried out in three phases. Phase
1 will include mobilization onto the site, installation of the initial upgradient water
diversion system, and processing of Pond 1 waste. Phase 2 will involve processing of
Pond 2 and 3 materials. Phase 3 will include the installation of the final upgradient
water diversion system and cap, final grading and revegetation, and demobilization from
the site.
A truck-mounted phase separator will be located onsite to process the waste. Pond
water will be used to charge the separator. Sludge will be pumped to the separator
(See Attached Sheet)
17. KEY WORDS AND DOCUMENT ANAL. YSIS
a. DESCRIPTORS b.IOENTIFIERSIOPEN ENDED TERMS C. COSA TI Field/Group
Record of Decision
Queen Ci ty Farms, WA (IRM/EDD)
Contaminated Media: gw, sediments, sludge
Key contaminants: acids, carc inogenic
compounds, chromium, heavy metals, PCB s,
phenols, tetrachloroethylene ( PCE) ,
toluene, trichloroethylene ( TCE), VOCs
.... DISTRIBUTION STATEMENT 19, SECuRITY CL.ASS (Tills ReporTI 21, NO, OF PAGES
None 24
20. SECURITY C~ASS iTlJis pI/gel 22, PRICE
I None
I!'. "or", 2220-1 (R.... 4-77)
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INSTRUCTIONS
1.
REPORT NUMSER
Insen Ihc LPA report number as it appears on the covcr of Ihe public;allon.
LEAVE BLANK
2.
3.
RECIPIENTS ACCESSION NUMBER
Reserved for use by c:l.:h report recipienl.
TITLE AND SUBTITLE
Tille shoulj IndlCalC de:lrly and briefly Ihc sUbJe~'1 ~'over:l~e "I' Ihe r~'porl. Jnd be d"I'IJy~'d I'IUl1l1n,'nll)'. S,'I ,"1'1111.'. If 11"..1. m''''JII~'I
type or otherwise subordlnale it to maIn Iltle. When a report I~ I,repared In mor\' Ih:ln "n~' V.,IUIII.... r~'I"';1I 111,' rrull:lry 1111.-.01.1" V,.I:IIII"
number and include sublitle for Ihe specific title.
4.
5.
REItORT DATE
Each report shaU carry a dale india tin. at lea~1 monlh and year. Indi\'ale Ih,' "a,., un ~III.-IIII \\;1' ,,'k,'I,'" (c',/(.. Jilt" "1 tnllc" Jtltc' "1
GPP'O".I. diltt 01 prcptUGtion. tIC.).
'ERFORMING ORGANIZATION COOE
Leave b&ank.
..
7.
AUTHORIII
Give nameCsI in \,<)nvcnllonal order (John R. DoC'. J, Robt." Doc'. c.te), LISI oIulhur\ :lnili:lllun if if .lif""r' rrulII Ilw I,,'rfurlllinj: "'j:;anJ'
zation. '
..
'fRFORMING ORGANIZATION REPORT NUMBER
In.11 if performln. orpnlZallon WIshes 10 ;ani", Ih., number.
t.
"RFORMING ORGANIZATION NAME AND ADDRESS
Give name. street. Cln, nale, and ZIP code. LISI no more Ihan IWO leveb of an ur~:lnll:lllunal hlrellrd,y,
10. 'ROORAM ELEMENT NUMBER
Use the propam elemenl number under whieh the repon W:l' p~epared. Subor"in.lle num""r' 11101)' be 111.-111.1...1 11\ I':lr,'nlh,'"",
11. CONTRACT/GRANT NUMBER
Insert contract or Ifanl number under which report WiI) prepared.
12. SPONSORING AGENCY NAME AND ADDRESS
Include ZIP code.
13. TYPE OF REItORT AND 'ERIOD COVERED
Indica Ie inleram finai. etr.. and .f applicable. dales covered.
14. SPONSORING AGkNCY CO'
Insert appropriate code
15. SUPPlEMENTARY NOTES
Enter information nOllncl\lded elsewhere but useful. such as:
To be published in. Supersedes. Supplements. ele.
Prcpued 11\ ,'ooper:lllun Wllh. I r;oIl,la'"", \II. 1'''',,'nl,',1 :II "\111"''''''''' ..f,
1.. A.TRACT
Include a brief (200 words 0'
significant bibliopaphy or II'
., factual summary of Ihc mOst ,it/nlll,'ani Inform:lllun ,'untalnl'" I" II". "'1'"11, 11111,. '''1''''''\111101111' 01
,lUre survey. men lion II here.
17. KEY WORDS AND DOCUMENT ~NALYSIS
(a) DESCRIPTORS. SeltcI from Ihe Thc~urus of I::nllinecrir.lloind SI:lelllllil' Term, the prup.:r :luIII"III\'d 1"'111' Ihall"enllfy Ihe nl:ll..r
concept of the research and are suffiCiently ~peclfic ilnll pre':llie to be Ulie" a, In\ln enlrlCs fur Iii I:lI"J.:1nj:,
(b) IDENTlrlERS AND OP[N.ENDED TERMS. Use identifien for prolcl.'t n:lm". .:ulle nam.:,. e\julpment dl:Slj:n:lfurs.l'I\'. U-.: "11\:11.
ended terms wrlllen In dcscnplor form for those subjects ror which no dl.'~rlplor 1.'~I)t~.
(c) COSA 11 Ht:LD GROUp. held and poup ilssianmenls .lrc to be laken frum Ihe 1965 ('05A'11 Sulll,'~1 (':lI\'I.!ury 1.i~1. Since thl.' m;&.
jorilY of c1ocumenl~ are multic1isclpltnary In nalure. the Primary belc1/Group ;a"'lnmcnll" WIll bu 'I",'ul.. 111\\ Iphnl.'. ar~':1 III' hUlII:ln
endeavor. or type or physical object. Thc applicationlsl will be crus).rderencell wllh -.:.'un\l:lry Ild"/! .ruul' J"I~II""'lIh thai ~,.II full,,~
the primary postlnglS). '
18. DISTRI8UTION STATEMENT
Denole releaYbihl)' to Ihe public or limllatlon for re,uon) uther Ihlln \C.:unly for cII..mrlc "M.I.'II.'J'I' 1./11/1""\'11." ( "I.' allv J~;III;lhllll)' ,,,
the public. wllh address :lnd pm:e.
1'..20. SECURITY CLASSIFICATION
DO NOT submit clits)lfied reportS 10 Ihe Nallonill TCl.'hnlC:lllnformiitiun 'crvil:e.
21. NUMBER OF PAGES
Insert the lotal number of pages. Includinglhis one and unnumbered pallc'. bUI ellduc.h: c.h,trlbullun 1"1. II any.
22. PRICE
Insert Ihe price ~t by the National rechnicallnformation S\'rvll.'e or th\' Government!'nnllng OITkl.'. II known,
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EPA/ROD/RIO-85/007
Queen City Farms, WA (IRM/EDD)
16.
ABSTRACT (continued)
using a pond skimmer which will be supplemented with mechanical excavation
of sludge. The phase separator will separate the sludge into four
components: grit, cake, oils, and water. The liquid portions of the
separated phases will be stabilized such that an exothermic reaction occurs
and no free liquid is present. Stabilized material and other solid products
produced during the phase separation will be treated as hazardous waste and
transported to a RCRA-permitted chemical waste landfill. In addition,
contaminated soils which surround the ponds will be moved into depressions
created by removal of the chemical sludge (prior to capping). Finally, to
assess the performance of this source control remedial action, a monitoring
system will be installed. Total capital cost for all phases of the selected
initial remedial measure is estimated to be $3,439,000. In accordance with
the CERCLA Section 106 Consent Order, the PRPs will establish a perpetual
trust to assure the continued funding of monitoring and maintenance
activities in the area of ponas 1, 2, and 3, where the Initial Remedial
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SITE:
ENFORCEMENT DECISION DOCUMENT
INITIAL REMEDIAL MEASURE ALTERNATIVE SELECTION
Queen City Farms. King County. Washington
DOCUMENTS REVIEWED:
I am basing mY decision primarily on the following documents describing
the analysis of the cost effectiveness of initial remedial measures for the
Queen City Farms site:
.
Assessment of Hydrogeology and Groundwater Qual i ty. Surfi ci a1
Aquifer. Queen City Farms. December 1983.
Focused Remedial Investigation, Queen City Farms, February 1985.
.
o
Focused Feasibility Study for Remedial Action, Queen City Farms,
June 1985.
o
Public Comment Work Plan, October 1985.
o
Summary of Initial Remedial Alternative Selection, October 1985.
o
Community Relations Responsiveness Summary.
o
Staff Summaries and recommendations.
DESCRIPTION OF SELECTED INITIAL RH1EDIAL ~1EASURE:
o
Phase Separation of Sludge: A truck-mounted phase separator will
be located on-site. Accumulated precipitation in the ponds (pond
water) will be used to charge the separator. Sludge will be
pumped to the separator using a pond skimmer which will ~e
supplemented with mechanical excavation of sludge. The phase
separator will separate the sludge into four components: grit, .
cake, oils, and water.
.
Liquid Stabilization: T~e liquid portions of the separated phases
will be stabilized such that an exothermic reaction occurs and no
free liquid is present.
Excavation of Working Surface Contaminated Soils: Contaminated.
soils which surround the ponds will be moved into the depressions
created by removal of the chemical sludge (prior to capping).
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2
.
Stabilized material and other solid products produced during the
phase separation will be treated as hazardous waste and be loaded
onto trucks and transported to a Resource Conservation and
Recovery Act (RCRA) permitted chemical waste landfill. .
.
Up-gradient Diversion System: A lined, gravel-filled trench will
be installed to intercept surface water run-off and shallow
groundwater flow before the water enters the Remedial Action Area.
Impermeable Cover: An impermeable cover system including a
synthetic membrane will be placed over the contaminated area.
During the final design phase of work, the desirability of
supplementing the proposed cover system with low permeability
soils will be assessed.
.
.
Monitoring System: A series of wells will be installed to monitor
the effectiveness of the system in preventing water from
contacting the waste. These wells will be screened at the contact
between the underlying low permeability strata and the overlying
sand and gravel deposits.
DECLARATIONS:
Consistent with the Comprehensive Environmental Response, Compensation,
and Liability Act of 1980 (CERCLA), and the National Contingency Plan (40
CFR Part 300), I have determined that the above Description of Selected
Initial Renedial t.1easure at the Queen City Farms site is a cost-effective
remedy and provides adequate protection of public health, welfare, and the
environment. The State of Washington has been consulted and is presently
reviewing the approved initial remedial ~asure.
All off-site disposal shall be in compliance with the policies stated
in Jack W. McGraw, Acting Assistant Administrator, Office of Solid Waste and
Emergency Response's May 6, 1985 memorandum entitled Procedures for Planning
and Implementing Off-site Response Actions. In addition, I have determined
that the implementation of the selected initial remedial alternative is more
cost effective than other remedial actions and is necessary to protect
public health. welfare and the environment.
October- 24 . 1985"
Date
~/kl..,-L",n'-1~(/ v...'-...
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-
SUMMARY OF INITIAL REMEDIAL ALTERNATIVE SELECTION
QUEEN CITY FARMS
SITE LOCATION AND DESCRIPTION
The Queen City Farms (QFC) site is a 320 acre parcel of land (S~ 1/2
See 28. T. 23N. R. 6E. WM) located approximately 2 1/2 miles north of the
town of Maple Valley in King County, Washington. The site includes a wooded
area. a lake known as Queen City Lake, six industrial waste disposal ponds,
an airstrip, several residences, and a gravel pit (Figure 1).
Land use in this area is predominamtly low-density residential, except
for King County's Cedar Hills Landfill immediately north of the site and
several small businesses in Maple Valley. There are approximately 105
public and private drinking water wells within a one-mile' radius of the site.
SITE HISTORY
The sitF was purchased by the present owners in 1952. The six ponds on
site were u~ for the disposal of industrial wastes from approximately 1955
to 1964. B~_duse of the time period few records exist regarding the exact
types of wastes taken to the site. Financial records indicate that the
Boeing Company was the major contributor of wastes at this site. Because
disposal activities ceased in the mid-1960's there were never any Federal
permits app1~~d for or received.
CURRENT SITE STATUS
In 1980 the six waste ponds were first sampled by the Environmental
Protection Agency (EPA) contractors. The analyses of water, sludge and
sediment samples identified the presence of 44 of EPAls 129 Priority
Pollutants (Table 1.).
In May 1983. EPA directed their contractor to prepare a test well
drilling program to investigate the area around the waste ponds., In July
EPA's contractor completed their first and only boring at the site. At that
point. QCF's contractor took over the field investigation, drilling an
additional 15 borings. This work was conducted under a CERCLA Section 106
Consent Order signed August 17, 1983. The analyses of 5011 and groundwater
samples confirmed the presence in the 5011 and shallow groundwater beneath
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..."
C'J
c:
;;u
",
....
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Pr;o~;ty Pol~uta~:s Id!n~if;ed in tne Cu!e~ City ~!~s ~as~e ~c~~s
~u~~er fol1o~;~9 chemical is highest concentration fcunc in ~a~:s per ~i11ior.
Me t! 1 s
Base/:ieu:~al E)(t~!~:~~hs
An11mony
.~.rsen i C
(J£ rj' 1 1 i ur:
."~~cm;um
Chrot:ii Ur.l
Copper
Lea a
Mercury
't!;cke1
Selenium
Silver
Zinc
, . :
3. :
C.,3
61
33.EoOO
820
11 00
O. Cl
236
2.3
0.b6
410
1 .2.4-Trich1oro~~n;~~~
1 .2-0; en 1 o~obenzene .
1 .3-Dichlorcoanzen~
n~Japthalene
Bis (2-EthyH.eJey1) Phthalate
Diethyl Pht~aldtc
'.Chrysen,
Anthracene
..Pyrene
Acid EJCtractiblts
2,'.6-'ir'cnloropnenol
P-Ch1oro-N-Cresol
2,4-uiChlorophenol
2.'-DirnetMyl~henol
2-~itropnenol
Pen:ac~loropheno1
Pht:no1
f~; s c e , , a n e 0 U s
CJar.1~e 34
Pher.olics 224
~e~t~cice~
-'PC: I 2,(0
1 ,,:;
Vc1!:'ie C~c!nics
.
w:er,zer.£
Ch 1 orobenzene
, . , ,1 - Tri cr. 1 oroethane
1,1-0i cr., oroethane
"Ch1c,.cfo~
1 ,1-0; cr.l oroetMy' en~
1 .2-rrdr.s-Oic~'crce:r!1e~e
C:S-l .3-~icr.lc~c:;:r::;:e":e
Etny1~el'\:er.e
Met~ylene Chlo,.ice
Titr~hloroetr.:1~~!
ioluene
.'T";Chlorc:r.y1ene
~nown carcinogen
"suspecteo carcinogen
TABLE 1
. -
I. ,
1 ~ -
3.5
2:C
2"
3S~O
140
790
460
- i
Zi 0
90
140
2c 1
SoC
',~ .
, 3 (;
:;:
C.C'
o. "
3.3
C.:f
C.C:S
6 ;;
C.;,
3C
315
1 3
62:
....
.. ...
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2
The findings of this 1983 investigation suggest that a significantly
contaminated shallow groundwater aquifer beneath the waste ponds is perched
on a layer of silt and glacial till stratum at a depth of from 16 to more
than 50 feet. However, approximately 200 feet south of the ponds, drilling
did not encounter this confining layer of till, but instead 75 to 100 feet
or more of dry sand and gravel. This information suggests that the perched
groundwater may be uspilling overu the edge of the till stratum and
percolating downward, which may create a recharge mound in an underlying
aquifer. Deeper on-site wells have shown the underlying aquifer to be
contaminated. Contaminants in this aquifer may pose a significant and
continuing threat to the other aquifer(s) in the area. Further studies will
be conducted during the Remedial Investigation/Feasibility Study (RI/FS) to
determine the continuity, gradient and relationship of these aquifers.
In August and September 1984, QCF conducted an additional field
investigation in the immediate vicinity of Ponds 1,2, and 3. The purpose
of this investigation was to determine the volume of the industrial wastes
- sludges in the ponds and the volume of contaminated sotl adjacent and
beneath these ponds. Seismic profiles, test pits, and soil borings were
also used to characterize the geology and extent of contamination in the
vicinity of the ponds.
This investigation determined the volume of industrial waste sludge in .
Ponds 1,2, and 3 to be approximately 5200 cubic yards, and the volume of
contaminated soil in the berms between the ponds, the soil immediately
beneath the ponds and in the "working surface" adjacent to the ponds to be
an additional 16,800 cubic yards. Chemical analyses of the sludge and some
of the soil samples confirm the presence of significant concentrations of
heavy metals, chlorinated hydrocarbons, phenolic compounds, polycyclic
aromatic hydrocarbons, polychlorinated biphenyls, ketones and aromatic
hydrocarbons.
Subsequent to this second investigation, QCF began work on a Focused
Feasibility Study to examine possible initial remedial measures for the
. removal and/or containment of the wastes in Ponds 1, 2, and 3 and in the
underlying and adjacent soils. On June 28, 1985, QCF delivered to EPA a
. draft Focused Feasibility Study report. This report examined eleven initial
remedial alternatives under the broad categories of infiltration prevention,
groundwater diversion, contaminated soils isolation or removal and chemical
sludge stabilization, solidification, isolation or removal, and incineration.
ENFORCEMENT
On September 16, 1985, EPA issued 44 Notice letters under Section 104
of CERCLA to a list of Pot~ntially Responsible Parties (PRP) provided to EPA
by QCF. These letters request generator information regarding disposal
activities at the QCF site. Most PRP's have responded indicating that
little or no records from that time period exist regarding wastes disposed
of at the site. To date, the Boeing Company has been the only PRP to
provide a brief listing of wastes taken to the site. QCF has financial
records from the operation of the site, but no records of waste type or
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3
ALTERNATIVE EVALUATION
There are twelve potential alternative courses of action identified
below. The initial remedial measures examined would all be characterized
as source control measures as defined in 40 CFR Part 300.68(e)(2). The-
primary objective of the proposed action at this site is to e1imin~te future
groundwater contamination from Ponds 1,2, and 3 and the immediate
vicinity. The general remedial alternatives considered to achieve this
objective were: infiltration prevention; groundwater diversion;
contaminated soil isolation or removal; and, chemical sludge stabilization,
solidification, isolation or removal. A brief description of each option
and the consequence of its implementation is presented.
Option 1: Physical Stabilization and Isolation
.
Description: Accumulated precipitation on the surface of the
ponds will be pumped and treated off-site. Chemical sludge in the
ponds will be physically stabilized by introduction of rock fill
or other material. The contaminated working surface will be moved
to within the pond area. and the berms, and contaminated soil will
be left in-situ. An up-gradient groundwater diversion system, an
impermeable cover and a down-gradient slurry wall will be
constructed.
.
Advantages: Minimizes further contact of precipitation and
shallow groundwater with wastes and that seepage from the ponds
could be intercepted. Short time to completion.
Disadvantages: Source of contamination (chemical sludge) remains
in place. Additionally, the build up of hydraulic pressure could
compromise the barrier properties of the slurry wall.
.
Option 2:
Solidification,- Diversion System, and Cover
.
Description: Accumulated precipitation will be pumped and treated
off-site. Chemical sludge in the ponds will be pumped to a
solidification unit, mixed witn fly ash, and returned to the
ponds. The contaminated working surface soils will be moved to
within the pond area and the berms will be left in-situ. An
up-gradient groundwater diversion system and an impermeable cover
will be constructed.
.
Advantages: Minimizes further contact of precipitation and
groundwater wit~ wastes. Solidification of chemical sludge
(reducing the potential for residual pond seepage). Lower
permeability of remaining wastes. Solidified chemical sludge will
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4
.
Disadvantages: Longer time to completion. source of contamination
remains in place. and no down-gradient barrier to capture residual
seepage. Sludge handling and solidification may be difficult
because of sludge viscosity.
Option 3: Solidification and Isolation
.
Description: Similar to Option 2 except accumulated precipitation
will be solidified along with chemical sludge and a down-gradient
slurry cut-off wall will be constructed to further isolate the
wastes. Berms will be left in-situ.
.
Advantages: Isolation of wastes. Solidification of all liquids
in ponds as well as advantages of Option 2.
Disadvantages: Longer time to completion. increased volume of
material caused by solidifying source of contamination which
remains in place. Sludge handling and solidification may be
difficult because of sludge viscosity.
.
Option 4: Solidification and Isolation with Water Treatment
o
Description: Similar to Option 3 except accumulated precipitation
will be pumped and treated off-site.
o
Advantages: Less time and same advantages as Option 4. chemical
sludge is solidified (reducing the potential for residual pond
seepage).
o
Disadvantages:
Source of contamination remains in place.
Option 5:
On-site Phase Separation. Solidification. and Isolation
.
Description: Chemical sludge and accumulated precipitation will
be pumped to an on-site phase separation unit. The separated.
organic phase will be mixed with a sOlidifying agent and returned
to the pOndS. Working surface soils will be deposited in pond
areas. The majority of the accumulated precipitation and
entrained water will be consumed through evaporation during phase
separation. Any residual water will be solidified. An
up-gradient ground water diversion system. an impermeable cover.
and down-gradient slurry wall will be installed. Berms will be
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5
.
Advantages: Volume reduction of material requiring
solidification, possible reduction in sludge toxicity due to hot,
caustic processing of chemical sludge. Reduced difficulty in
handling sludge with higher temperatures.
Disadvantages: Longer time to complete than some earlier options,
possible air pollution impacts associated with elevated
temperature (approximately 180 F) processing of chemical sludge.
.
.
On-site Phase Separation, Solidification, and Off-Site
Chemical Landfill Uisposal
Description: Similar to Option 5 except the separated solids and
any residual waste (solidified) will be transported to a chemical
landfill for disposal. Also, the down-gradient slurry wall is
omitted. Separated solids would likely not require further
solidification.
Option 6:
.
Advantages: Removal of principal contaminant.source, possible
reduction in sludge toxicity due to hot, caustic processing.
o
Disadvantages: Longer time to complete then some earlier options,'
possible air pollution impacts associated with
elev1ted-temperature processing of chemical sludge.
Option 7:
Off-site Chemical Landfill, Solidification and Water
Treatment
o
Des~ription: Accumulated precipitation will be pumped and treated
of ~ite. An up-gradient diversion system will be installed.
Cht,7I dl sludge from the ponds will be pumped, solidified and
tran$ported to a permitted chemical landfill. An impermeable
cover will be installed. Berms will be left in-situ.
.
Advantages:
Removal of principal source of contamination.
.
Disadvantages: Larger volume of material to dispose of off-site
because sludge in ponds not separated into phases prior to
solidification.
Option 8:
Off-site Chemical Landfill of Sludge, Berms, and Working
Surface Soils with Water Treatment
.
Description: Similar to Option 7 except the berms and working
surface soils will be excavated and transported to a permitted
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6
.
Advantages: Removal of principal source of contamination as well
as contaminated soil.
.
Disadvantages: larger volume of sludge and contaminated soil to
be disposed of off-site.
Option 9: Off-site Incineration of Chemical Sludge
.
Description: Accumulated precipitation will be pumped and treated
off-site. An up-gradient diversion system would be installed.
Chemical sludge will be pump/excavated and shipped to a permitted
waste incineration facility. Contaminated working surface soils
will be moved to within the pond area and the berms would be left
in-situ. An impermeable cover would be installed.
Advantages: Removal of principal source of contamination.
.1
.
.
Disadvantages: Probable delays in incineration due to limited
domestic capacity. May not be practical to ship in tankers. If
drums necessary, cost and time will increase significantly (20,000
drums requ ired).
.
Off-site Incineration of Chemical Sludge, Berms,
and Working Surface Soils
Desc.lption: Similar to Option 9 except berms and working surface
soils will also be shipped to a permitted waste incineration
facility.
Option 10:
.
Advar~~ges: Removal of principal source of contamination and
con1 ,n° "ated soil.
.
Disadvantages: Very long time to complete. Probable delays in
incinerator due to limited domestic capacity. May not be
practical to ship in tankers. If drums necessary, cost and time
will increase significantly (20,000 drums required).
.
On-site Incineration of Chemical Sludge, Berms, and
Working Surface Soils.
Description: An up-gradient diversion system will be installed
and an on-site incinerator will be constructed. Accumulated
precipitation, chemical sludge, working surface soils, and berms
will be incinerated. Ash generated from the incinerator will
either be placed in the area of the ponds or disposed of off-site
at a hazardous waste landfill. In either case an impermeable
cover will be installed.
Option 11:
,
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7
.
Advantage: Removal of principal source of contamination as well
as a portion of the contaminated soils.
Disadvantages: Probable delays due to difficulties of acquiring
on-site incinerator and possible permitting requirements.
.
Option 12:
No Action
Under this option no remedial activities would be conducted at the site
at this time. The overall RIfFS would be conducted over the next year. Any
necessary remedial activities identified in the RIfFS would then be
conducted. Because of this potential delay of up to several years and
because any final remedial action would likely include the removal of the
sludges from Ponds 1. 2. and 3. it was determined that no action was
inappropriate.
ALTERNATIVE SCREENING PROCESS
Criteria considered in the screening included technical feasibility.
effectiveness. institutional requirements. costs. and other site and
technology-related considerations. Because the overall RIfFS has not yet
been conducted. the final remedial actions for the site have not yet been
determined. For this reason. it is most important that the chosen IRM not
interfere with and. to the extent possible. be compatible with future
activities at the site.
Options 1 through 5 were eliminated early in the screening process
because in each of these options the sludge would remain on site leaving
over a million gallons of a highly concentrated source of contamination.
While these options would attempt to isolate the sludge in the pond area. it
is unlikely that on-site disposal of such highly concentrated wastes would
be compatible with the final remedial action at the site.
Options 9. 10. and 11 were next eliminated because of the limited
incinerator capacity around the country at present. particularly in the
Northwest. This limited capacity could potentially extend the time of this
IRM activity to several years which would be incompatible with future RIfFS
activities on site. These three options were also the most expensive.
because of increased transportation costs and the cost of incineration
itself.
These initial screenings narrowed the selection down to Options 6. 7.
and 8. All of these options would remove the sludge from the three ponds
for disposal at a RCRA-permitted disposal facility. The three options
varied primarily in the methods of handling the sludge from the ponds and
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8
EPA favored Option 6 because it employed volume reduction (phase separation
and solidification) processing to minimize the amount of source material
that would have to be disposed of at a RCRA facility. The remaining
contaminated soils would be consolidated in a central location followed by
capping and isolation via a groundwater diversion system. EPA believes
Option 6 will be most compatible with future RIfFS activities at the site.
Tables 2 and 3 list the options and the technologies examined, and also
the relative costs of each option.
COMMUNITY RELATIONS
The following documents were made available for public comment:
.
Assessment of Hydrogeology and Ground Water Quality, Surficial
Aquifer, Queen City Farms, December 1983.
Focused Remedial Investigation, Queen City Farms, February 1985.
.
o
Focused Feasibility Study for Remedial Action, Queen City Farms,
June 1985.
o
Public Comment Work Plan, Option 6, October 1985
Public Comment CERCLA Section 106 Consent Order for implementing
IRM activity, October 1985.
.
These documents were available for review at the Maple Valley Library
and also at the EPA Region 10 library in Seattle.
There was a public comment period for the Work Plan from October 2
through October 16. On October 10, a public meeting was held in Maple
Valley to present and discuss both the Work Plan and the Consent Order.
Notices of the meeting and public comment period were sent out to 68 nearby
residents, county and state agencies, elected officials, and local
newspapers. The notice of the pUblic meting was published in two of the
local newspapers. A second pUblic comment period for the Consent Order was
scheduled from October 10 through October 24.
Eight people attended the public meeting including two representatives
of King County, an attorney for Queen City Farms, two representatives from
environmental groups and two residents. .
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Table 2 - Coat S.-ry for Optlona
Cost in Thoussnds of Dollars
Ite. 1 2 3 4 5 6 7 8 9 10 11
-
Mobilization 100 100 100 100 100 100 100 100 100 100 1600
Up-gradient DlverlloD 14 14 14 14 14 14 14 14 14 14 14
Povn-Gradlent Slurry Cut-otf 239 239 239 239
Imperweable Cover 131 131 131 131 131 131 131 131 131 131 .131
Phystcal Stabi1izatton 471
Soltdification 916 1107 916 378 235 656 656
Off-Site Dtlpolal 1256 3271 8524 0-3015
Incineration 5743 18987 13500
On-Site Phale Separation 642 642
Off-Site Water Treat.ent 140 140 140 140 140 140 140
Excavation, pu.plng and 5 5 5 5 88 5 88 88 .
Te.porary Tanks
On-Site Dhpolal 18 63 73 63 35 18 18 18
Ceneral Conltructlon 125 125 125 125 125 205 200 235 200 200 235
Non-Conltruction 205 265 265 265 265 265 235 385 265 385 385
Subtotal 1443 1759 2059 1998 1929 2866 4770 10'273 6616 20045 15953-189.
Contingency 289 352 412 400 386 573 954 2055 1323 4009 3190- 37~
Total COlt 1732 2111 2471 2398 2315 3439 5724 12328 7939 24054 19J ~3-2271
------------------------------------~--
Construction Time
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Option Summary
-.
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Option 1 . . . . . .
Option 2 . . . . .
Option 3 . . . . .
Option 4 . . . . . .
Option 5 . . . . . .
Option 6 . . . . .
Option 7 . . . . . .
Option 8 . . . . .
Option 9 . . . . .
Option 10 . . . .
Option 11 . . . . .
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9
CONSISTENCY WITH OTHER ENVIRONMENTAL L~S
All facets of the proposed Initial Remedial Measure will be consistent
with the technical requirements of other environmental laws. The off-site
transportation and disposal of the processed waste sludge and contaminated
soil will be in accordance with appropriate RCRA regulations, including
manifesting of wastes and shipment to a RCRA-permitted facility. The cap to
be constructed over the site will be consistent with RCRA guidelines.
Monitoring will be conducted to ensure that the groundwater diversion system
is operating properly to minimize migration of contaminants from the area.
Long term closure and monitoring of the site will be addressed at the
completion of the final remedial activities.
RECOMMENDED ALTERNATIVE
-1
The recommended Initial Remedial Measure is to be carried out in three
phases. Phase 1 will include mobilization onto the site, installation of
the initial upgradient water diversion system, and processing of Pond 1
waste. Phase 2 will involve processing of Pond 2 and 3 materials. Phase 3
will include the installation of the final upgradient water diversion system
and cap, final grading and revegetation, and demobilization from the site.
.
Phase 1 - Mobilization, Pond 1 Sludge Processing, and Off-Site
Transport.
Mobil ization
Mobilization onto the site will be done in six steps, which are as follows:
1.
2.
3.
4.
5.
6.
Set-up of contamination and personnel protection zones
Preparation of the working area .
Bringing in utilities
Set-up of support facilities (field offices, crew quarters, and
decontamination units)
Importation of supplies and process equipment set-up
Activation of the monitoring systems
These activities will be conducted concurrently with the installation
of the temporary upgradient water diversion system. However, both the
mobilization and water diversion system activities will be completed prior
to the processing of Pond 1 waste. The site layout for construction 'and
processing activities is shown in Figures 2 and 3. Three work zones will be
established as shown in Figure 2. Zone 1 will be those areas where direct
contact with the ponds is likely. In general, entry to this lone will.
require Level C protection which will be upgraded to Level B during the
excavation operations. Zone 2 generally encompasses those areas which have
-------
W.ork Zones Location Map
-,
I
I'
..~
. Zone 1
otlC-4
fLll2I Zone n otlC-4A
~ Zone m
~ Roadways
\>
. 0-~
/ 'lJ Queen CUy Lak. ~..
( 0 HA-3
:~:.
..G.\#;-;~~
~)LJC~
O,p..
60
- -----
o HA.2
o
200
400
Scale In Feel
415
c
'ious Explorallons
III p- 1
Te51 PII toea
Jnd Number
FIGURE 2
-
Trill"'" ..' -.
-------
60
- -----
I
~ I
\ (
) Clean Bri' Siockpile
"-
Soo
""'-
I "'-.
Siabilizing Agenl \
Siorage ~ ~
Truck Decon Unil
Emplovee Quarlers
(lunch Aoom/Decon)
o 200 400
Sca'e In Feel
475
o Previous E xplorallons
fU P-1
Tesl PII locallon and Number
. .
FI GURE 3
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10
stockpiled. Protection within Zone 2 is anticipated to Level D; however, as
appropriate, protection could be upgraded as far as Level B. Zone 3 is
comprised of the areas primarily involved in truckloading and the
decontamination cleanup activities. This is a transitional zone to the
clean surrounding areas and no special attention is required in this area.
Set-up Processing Equipment: With the site prepared. the process
equipment and supplies will be brought in. The principal piece of process
equipment is the phase separation unit. This piece of equipment has two
major components: the pond skimmer/intake structure. and the phase
separation/cleaning unit. The large processing unit which does the phase
separation/clea~ing will be spotted such that the pond skimmer/intake
structure and its associated umbilical cord to the processing unit will
allow the skimmer mObility across the entire extent of Pond 1.
The phase separator also requires three support units to take the
recovered byproducts. They are: tankage for the organic fraction.
transport bins for grit. and transport bins for sludge cake. All three of
these support units will be located near the phase separator. To prepare
the wastes for transport and disposal off-site. a stabilization unit will
also be spotted within Zone 2. This batch mixing unit also requires the
support of a stabilization agent storage and feed unit. Output from the
batch mixing unit will be transp~rted to a setup stockpile near the.
truckloading pad. Concurrently. near the field office. a truck scale will
be placed for control of transport activities.
The slurried waste drawn up by the pond skimmer goes onto a shaker
washer device where high pressure nozzles clean and separate the large grit
from the organic fractions. The fractions containing substantial amount of
fines goes through a centrifuge unit where the liquid portion including
water and organics is separated from the solid fines which come out as a
cake. The water and organic fractions are then sent to a phase separator
where the water is recycled back into the pond skimmer after being
reheated. The organic fraction is separated out and put in tankage for
eventual stabilization.
Grit and cake coming off the centrifuge will be disposed of off-site.
The liquid organic fractions from the phase separator will be put in
temporary tankage and eventually stabilized in the ba~h mixer plant.
To dispose of contaminated water and liquid organic fraction off-site.
stabilization to remove the free liquids will be requ.ired. To accomplish
this in a pug mill type device. a set weight of Pozzolanic stabilization
agent and/or other stabilizing materials will be loaded into the batch
mixing unit. The liquid fraction will be metered as the pug mill mixes the
two components. The two components then undergo an exothermic reaction
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11
.
Phase 2 - Processing of Pond 2 and 3 Sludge
Phase 2 is the processing of Pond 2 and Pond 3 sludge. The activities
involved in processing wastes from these ponds are similar to those'
described above for Pond 1 except that approximately the last foot of sludge
from Pond 3 will be mechanically excavated and loaded for stabilization.
Similarly, upon excavation of Pond 2 the remaining stored dirty grubbing
materials will be placed in the pond. It is anticipated that after Pond 3
excavation, dirty grubbing materials will be gone and only working surface
materials will be going into Pond 3. '
.
Phase 3 - Installation of Permanent Upgradient Diversion System,
Monitoring System, Cover, Final Grading and Demobilization
Work in Phase 3 will start as soon as Pond 3 sludge is removed,
processed, and hauled off-site. Tne contaminated working surface soils,
demolished asphalt work pads, and other contaminated soil will be placed
into Ponds 1,2, and 3. .
Once all the area outside the pond site has been cleared, clean
backfill will be imported to raise grade to desired elevations. The c~ver
system subgrade will be compacted and graded.
The purpose of the upgradient diversion system is to intercept surface
water and near-surface groundwater that flows between the ground surface and
the top of the low permeability strata (till or silt) which underlie the
ponds. The water that flows above these strata is a major source of
groundwater flowing beneath the ponds.
The upgradient diversion system will be constructed by excavating a
trench to a depth of at least 0 feet into the till on the northeast side of
all three ponds (see Figures 4 and 5). The downslope, bottom, and upslope
(to above drain pipe invert) side of this trench will be lined with
impermeable membrane to prevent water that enters the trench from continuing
to flow downgradient towards the pond. After the impermeable membrane is
installed, filter fabric will be used to form an envelope about the trench
and a perforated PVC pipe will be laid in the bottom,of the trench. The'
trench will be backfilled with a free-draining sand and gravel so that water
that enters the trench can flow freely down into the perforated pipe 'drain
to the system outlet. In order to prevent surface water from flowing over
the trench, a berm approximately 2 feet high will be constructed on the
downslope side of the trench.
After the sludge has been removed, the ponds will be backfilled with a
combination of clean and contaminated soils. The backfill material will
include contaminated working surface soil as well as contaminated vegetation
that has been removed from the site. The contaminated vegetation will. be
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SA
."-,
-"'...
......
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-/
- ..-- /'
1"
~
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/
r
"'------ I
-------------J
d Number
W.II Location an
d lIo""or'"o
PrOOOI. Numbar
W.II Location and
lIonltorlno
EI'"InO d Location
S.ctlon Oaslqnatlon an
Profll.tCroll
SA
$HC-1
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100
,
o
..,
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Cover
FIGURE 4
-------
Generalized Subsurface Profile 1-1'
1
S20r
500
: 480
IA.
.E
Cover
Drain
Uncontaminated
SILT FILL
~
c
~
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~ 460
UJ
"""-
SLUDGE ./"
~
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-
SLUDGE
~AW?' .~
440
420
---
--..-----------
-
Typlcel Coyer Configuration
Detail 3
GnAVEL--...... /Ilter Fabric
~_--"T.-yr--
SAND ~ fiLL
Sil T Fill
80~r~__-
- CLAY liner
~
-5:~~~~'~
Working Surlace Solis and \
Cover Layer
...-
L--SLUDGE Clo b
F/~y'IA..\V'/A.'V N";:"'\
Native 5011
FIGURE 5
-------
6-inch Topsoil wilh Grass
~'OOI Cobble Animal Barrier
-~r'.ne:": :-.: .:.': .:.-.::. : ~ .::~ '.:.-:::: 2.1001 SAND Cower
~~~~~~~.... ClA'l-
-...
-n/f$!V".--/
-
_lIr....~
Id Unconlaminaled ~I~~
° be remo..edl1
~- -
Typical
Cover
Configuration
E.isllnll Ground Sur lace
5" Slope~
\1
SLUDGE ~
- ",."W7XS.V?A...tVJ'7- - - - ./"
----- ------
---- --
--
--
---
Detail 2
Ma.imum Cobble
Slope Prolecllon
5H: IV 8B
~-~--<: C..
-----r--- ~ /I b
Geomembrane / ~. .-' is'
/ mon
/,,-
"-Filler Fabric
Lo'2-inch ~ PVC
Perloraled Pipe
FIGURE 5
Right Side
Upgradient
Diversion
System
-----
o
_.
Scale .n reo.
1.
----- -
20
-------
.
12
The primary elements in the cover system will be a 2 foot thick layer
of clay and a flexible geomembrane to prevent surface water from penetrating
the subsoils (see Figure 5). A geomembrane consisting of 30 mils of
reinforced PVC will be placed on this impermeable material. To protect the
geomembrane, an additional 18 to 24 inches of sand will be placed on top.
In order to protect the geomembrane from burrowing animals, a 24-inch layer
of cobbles will be placed on top of the sand. The cobbles will range from
3-inch to 12-inch stone. During an appropriate season the cobbles will be
covered with 6 inches of topsoil and vegetated with grasses.
To assess the performance of the source control remedial action, a
monitoring system will be installed. The system will consist of seven wells
located as shown on Figure 4. Six new wells will be installed. An existing
well (HC-l) will be incorporated into the monitoring system. As shown, the
wells are located to monitor water levels above the low permeability units
both upgradient and downgradient of the ponds.
Performance monitoring will be completed after the site construction
activities have ended. This monitoring program will consist of measuring
water levels in the monitoring wells using a chalked steel tape. and
assessing the condition of the upgradient diversion system, cover collection
system. and the cover system. Measurements will be made on the following
schedule:
.
Monthly during the first year and quarterly during the second year
after construction.
.
Semi-annually the next two years (years 3 and 4 after
construction).
.
Annually thereafter in accordance with the provisions in the
Consent Order.
OPERATION AND MAINTENANCE
In accordance with the CERCLA Section 106 Consent Order, the PRPs will
establish a perpetual trust to assure the continued funding of monitoring
and maintenance activities in the area of Ponds 1, 2. and 3, where the
Initial Remedial Measures will be conducted. The trust shall be approved by
EPA and funded by the PRPs upon completion of the activities in the work
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13
SCHEDULE
Seven key milestones have been established under the Consent Order for
the completion of the Initial Remedial Measures: Hazardou
On-site solidification andfor stabilization of sludge from Ponds Informatic
1. 2. and 3 (February 28. 1986); Transportation to disposal site (March US. EPA R.
31. 1986); Placement of work i ng su rface soi 15 into Ponds 1. 2. and 3 ! Phlladelp
(April 30. 1986); construction of final upgradient diversion system ~ --
(June 30. 1986); Construction of cover system without planting of
vegetation (June 30. 1986); Installation of monitoring wells (June 30.
1986); Final implementation of work plan elements (July 31.1986).
FUTURE ACTIONS
A work assignment has already been issued to one of EPAls remedial
contractors to develop a work plan for the upcoming overall RIfFS. This
work plan should be completed by the end of January 1986 and will serve as
the basis for negotiating the RIfFS to be conducted by the PRPs. It is too
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