Environmental Protection
Agency
Emergency and
Remedial Response
June 1984
SEPA
Superfund
Record of Decision:
Ponders Corner Site,
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TECHNICAL REPORT DATA
(Please read Instructions on .the reverse before completing)
1. REPORT NO. 12. 3. RECIPIENT'S ACCESSION NO.
EPA/ROD/RIO-84/002
4. TITLE AND SUBTITLE 5. REPORT DATE
SUPERFUND RECORD OF DECISION 06/01/84
Ponders Corner Site, WA 6. PERFORMING ORGANIZATION CODE
7. AUTHORIS) B. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT ~O.
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED
U.S. Environmental Protection Agency Final ROD Report
401 M Street, S.W. 14. SPONSORING AGENCY CODE
Washington, D.C. 20460 800/00
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Drinking water wells in the Tacoma, Washington area were sampled for contami-
nation by purgeable halocarbons. The sampling results showed that Lakewood Water
District's production Wells H-l and H-2 were contaminated with 1,2-(trans)dich-
loroethylene, trichloroethylene and tetrachloroethylene. These wells were taken out
of production.
It was determined that the septic tanks and the ground disposal area of a com-
mercial cleaners were the probable source of well water contamination. Solvents used
in the dry cleaning process were disposed of in the septic tank and liquid wastes
consisting of solvent-contaminated sludges and water draw-off were disposed on the
ground outside the cleaners. The cost-effective initial remedial measure for the
site is construction of air stripping towers. The 3-year present worth cost for
this remedy is estimated to be $1,163,000 and annual operation and maintenance is
estimated to cost $82,000.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. OESCRIPTORS b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Record of Decision
Ponders Corner Site, WA
Contaminated media: gw, soil
Key contaminants: volatile hydrocarbons,
organic solvents
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RECORD OF DECISION
INITIAL REMEDIAL MEASURE ALTERNATIVE SELECTION
SITE: Ponders Corner, Washington
DOCUMENTS REVIEWED:
I have reviewed the following documents describing the analysis of
cost-effectiveness of Initial Remedial Measure alternatives for the
Ponders Corner Site:
.IIFocused Feasibility Study: Ponders Corner Well Water Treatment
Facility, lakewood, Washington, II May 1984.
.The attached IISunmary of Remedial Al ternative Sel ection, Ponders
Corner, Washington,1I May 1984.
.Community Relations Responsiveness Summary.
.Staff'sunmaries and recommen~ations.
DECLARATIONS:
. .
Consistent with the Comprehensive Environmental Response, Compensation,
and Liability Act of 1980, and the National Oil and Hazardous Substances
Contingency Plan, I have determined that the construction of air stripping
towers at Lakewood Wells H-l andH-2 effectively mitigates and minimizes
damage to, and provides adequate protection of public health, welfare, and
the environment. I have also determined that the action being taken is
appropriate when balanced against the need to use Trust Fund money at
other sites. In addition, I have determined that the construction of air
stripping towers is more cost-effective than ot~er remedial actions and is
necessary to protect public health and welfare and the environment from a
potential risk ~mich may be created by a continued shut-down of Wells H-l
and H-2 and, therefore, consistent with Section 101 (24) of CERCLA.
,
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I " .t ,-; ....; . \ :..: -, .\
ERNESTA B. BARNES'
REGIONAL ADMINISTRATOR
JUN
DATE
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SlMMARY OF REr-fDIAL AL TERNATI VE SELECT ION
PONDERS COR.~ER, WASH INGTON
A.
Site LDcation and Description
Lakewood Water District's Production Wells H-l and H-2 are located in the
Ponder sCorn er nei ~borhoo d 0 f Lakewoo din Pi erc e County, Wash i ngto n, jus t
north and west of McChord Air Force Base and southeast of Interstate 5, as
shown in Fi gures 1 and 2. Lakewood is a predominantl y comnercia 1 and
residential area located south of the Ci ty of Tacoma.
Well s H-l and H-2 make up the Ponders Corner well field. Both well s are
apP'"oximately 110 feet deep, and together they can supply up to 2.800
gallons per minute (gpm). Before the well s were taken out of production
because of contamination, they suppl ied water to the Ponders/Nyanza Park
area and provided over 10 percent of the District I~ needs.
B. Si te Hi story
In July 1981, EPA sampled dri nking water wells in the Tacoma, Washington,
area for contami nati on by purgeabl e halocarbons. The sampl i ng showe dthat;
Lakewood Well s H-l and H-2 were contaminated with 1,2- .
(tran s )di chl oroe thyl ene, tri chl orOe thyl ene. and te trachl oroe thyl ene. In
mi d-h.I gust 1981. La kewood Wa ter Di stri ct took Well s H -1 and H-2 out of - ..
production, notified its customers of the well contamination. and
requested that a water c onservati on pl an be foll owed.
A subsequent inspection-and sampling effort by EPA and the Washington
Department of Ecology (WDOE) detennined that the septic tanks and the
ground disposal areas of a comnercial establishment known as Plaza
Cleaners were the probable sources of well water contamination. Plaza
Cleaners is located several hundered feet north of the well s and across
Interstate 1-5.
In the past, Pl aza Cl eaners operated a dry cleaning and 1 aundry business
with dry cleaning machines. reclaimers (dryers). and comnercial washing
mathi nes. Pl aza Cl eaners processed approximately 6,000 pounds of dry
cleaning and 2.000 pounds of laundry per week. Some solvents used in the
dry cleaning process were disposed of in the Cl eaner's 4,250-gallon septic
tank system and were flushed through by approximately 12.000 ga110ns per
day of wastewater from the 1 aundry operation. Al so, some liquid wastes
contafnf ng sohent~ were deposf ted on the ground outsi de the bufl di ng.
The 1 fquid w~tes disposed on the ground were solvent-contaminated sludges
and water draw~ff from the vapor recovery system. Thi s water draw~ff
contained from 60 to 100 ppm chlori nated sohents and amounted to about 30
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TACOMA
AREA OF FIGURE 2.2
Pond.... Com.
2 4 6
. . .
Scale in Miles
10
.
8
.
@
~
n
SEATTLE
RENTON
.
.
1.5
FIGURE 1
PONCERS CORNER
LOCATION MAP
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.,
r,
,
,
L
f')
n
., I;~".'
~
. .
LJ.tt
o I
.
BASE
..,
~ , c.-.,,,
""
-
\
.r.--:-.~. ,.. _. . - G.-
4.. . . ... .8. . -.,- .. ~
E.."'GddMt~.,,'-". '';' .1 -~COft 1118 :.
=-:'1~~~ '- -{-.- ; e..
A LAKlWoOD WATIJI DIITJIICT '..ODUcnON WILL
-.
IOUAca VIOl ,....""" OUAD&NGLI:
.,.... "coo.. WA8MtNGTON
j
-I-
i
I~I
FIGURE 2
VICINITY MAP
PONDERS CORNER F.FS
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,
Contamination 1 evels at and near this source have been measured as hf!tt as
the following values:
Tn chl oroe tt1Yl en e
Te trach 1 oroethy 1 ene
l,2-Ctrans )di chl oroethyl ene
Co ncentra ti on
Parts per 811110n (ppb)
3,600 1 n sludge
3,460,000 1 n so11
9,600 in sludge
Groundwater movement dictates the spread of th1 s contamination when the
wen s are not operating. Thi s movement has not been fully characterized
but f s known to flow generally 1 n a northwest direction. When one or both
wen s are operated, the maj or f1 ow 0 f the con tam; nants ; s toward the well.
WDOE took over enforcement and cleanup actions at the s1te under the
State's Water Pollution Control law. WOOE issued an administrative order
to the Cl eaners in early sunrner of 1983 to assess the problem and clean up
the source. The fonner and current owners of Plaza C1eaners sUbsequently
signed a stipulated agreement with WDOE before the State Pollution Control
K!an ngs Board.
As a resul t of the order and agreement, Pl aza Cl eaners stopped disposal of
so1vents to the ~und and septi c tank s, and much of the contaminated
surface so11 has been dug out and repl aced with uncontaminated soil. Irr .
addition, comnerc1al1aundry operations ceased. decreasing the possibility
.of further flush1ng of solvents into the groundwater from the septic tanks.
It is therefore believed that continuing discharge of contam.1nating
sol vents into the ground has been stopped and th at res1 dual so1vents in
the so11 and the underlying aquifer constitute the source that is
presently contaminating Wells H-l and H-2.
The excavated contaminated so11 wa s removed to the P1 aza C1 eaners park; ng
lot, where it remains tOday (albeit covered by pl astic). Al so. WDOE was
unable to get the C1eaners owners to develop and implement a plan for
protection of the aquifer from possible further contaminant releases from
Plaza Cleaners. 'This is important, as it 1$ expected that a substantial
amount of solvents were flushed throug, the septic tank system. and remain
under the property as a contfnuf ng source of contamination.
EPA sent combfnatfon notfce/l04(e) 1 etters to the current and fonner
owners of PlaH C1eeners f n September 1983. In January 1984 WOOE turned
the site over to EPA. A federal.lead SUperfund fnvestigatfon was .'
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C. ' CUrrent Site Status
Ouri ng December 1983. a 10-day pumping test was conducted on Well H-2.
Sample analysis indicated that the solvent concentrations decreased during
the first few days of testing and then tended to 1 evel off. Fi gure 3
shows the data from these tests for tetrachl oroethylen'e and
1.2-(trans)dic:hloroethylene. Trichloroethylene (TCE) was also detected at
less than 50 ppb but was not quantifiabl e. Subsequently. in February
1984. TCE was quantified at 28 p~. These data have been used to provi de
a desi gn basi s for i nfl uent treatment.
Al thoug, the concentrations appeared to 1 evel off after several days
during the test. individual samples still showed variations from the
average. In addition. earlier tests at the source showed much hig,er
concentrations of contaminants and a greater margi n for variation. For
these reasons. the contamination 1 evels at the 2-day point duri ng the pump
test were selected as a conservative desi gn basi s contaminant loadi ng for
the treatment facility. A TCE level of 40 p~ was selected to provide
conservatism above the measured 28 ppb.
Design basis contaminant loadings are therefore as follows:
Tri ch 1 oroe thyl en e
Te trach 1 oroethy 1 ene .
1 .2-(tran s )di chl oroe thyl ene
~
40
250
360
These values are assumed to apply to 'both wells because the. wells are
close together and pump from, the same aquifer. Either well would
therefore receive essentially the same input after long-term pumping.
All members of the chloroethylene series are central nervous system
depressants. Acute exposure results in lassitude and mental fogginess.
Complaints of mil d irritation. li ghtheadedness. and mil d headaches have
been reported. Prolonged occupational exposure to tri chloroethylene has
produced impainnent of the per1~eral nervous system. The long-tenn.
low-dose effects on the central nervous system. however. have not been
well characteri zed in the scienti fi c literature. kute exposures can
produce damage to 1 fver and kidneys. Trichloroethylene. however. is a
less potent renal toxin compared to chlorofonn or carbon tetrachloride.
Long-tem toxicity of trichloroethylene appears to depend principally on
itsmetabol1c,prod~ts. As a result, other chemicals that enhance or
inhibit its metabolism may act to increase or decrease its toxicity.
Simil ar effects woul d be expected ~i th the other two chloroethylenes
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.~
-
--
-
.
400
t'
~ 320 . . .
~ DESIGN PT. 250 PPB
.
~ 240
I . .
I .
160
80
o
o
12/8/83
I
1
2
3
4
5
DAYS
8
7
8
8
10
12/16/83
. TET'AACHLOROETHYLENE
.1,2 (TRANS) DlCHLORO ETHYLENE
FIGURE 3
PONDERS CORNER
10 CAY PUMP TEST - WEll H2
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Al though few studies have been perfonned, the three chemical s have not
been found to be teratogenic in laboratory animals tested. All chemicals
appear to require metabolic activation for any mutagenic effect.
Technical-grade trichloroethylene, which is mutagenic if metabolically
activated, contains epichlorot,ydrin and epoxibutane, which are more potent
mutagens than the pure TCE. l,2-(trans)dichloroethy1.ene has been found to
be nonmutagenic. There is generally insufficient evidence on the
mutagenicity of the three chemicals.
Both trichloroethylene and tetrachloroethylene have been shown to be liver
carcinogens in at least one strain of mice. No data are available on the
carcinogenicity of l,2-(trans)dichloroethy1ene.
EPA has developed preliminary risk level s for human carcinogens based on
analysis by EPA IS Carc i nogen As sessment Group. Its estimates for
trichloroethylene and tetrach10roett,y1ene are shown in Table 1. For
example, a trichloroethylene concentration of 2.7 p~ (with a risk level
of 10-6) is expected to increase the number of cancer deaths by one for
a million people exposed to the chemical in drinking water over a lifetime.
No data are available to describe the potential carcinogenicity of
l,2-(trans)dich10roett,y1ene. Icceptab1e drinking water concentrations for;
noncarcinogenic risks are shown in Table 1 for this chemical. .
The concentration desi gn points. reached after 2 days of pump; ng at Well.
H-2. are 40. 250, and 360 p~ for trichloroethylene, tetrachloroethylene,
and l,2-(trans)dich10roe~lene. respectively. Table 2 shows the
contamination 1 eve1 s, the cri teri a, and compari sons among these val ues.
TABLE 2
LAK5IOOD ~TER DISTRICT \!ELLS H-1 AND H-2
COtoPARISON OF CONTNo1INANTS AND CRITERIA
FOR DRINKING ~TER
(OJ NCEN TRAT ION- l' pb)
Cri ten aa Well Leve 1 b
Compari sonc
Tri chl oroe tt1yl ene 2.7
Te trach 1 oroethyl ene 0.8
1,2-( 1:I"an 5 )di chl oroe 1:t\Yl ene 27
40
250
360
14.8
313
13.3
GAs establis~d by ~Tacoma-Pi eree County Heal th Department.
bBased on levels at 2 days during the 10-day pumping test.
cWell level divided by criteria. Factor by which the 'design point
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hb~ 1
RISK LEVELS ASSOCIATED WITH
DRINKING WATER CONTAMINANTS (ppbt
,
Increased Cancer Riska
10-7 10-6 10-5
Considered Acceptable
for Human Use .
I-day
10-day
Chronic
Trichloroethylene
0.27
0.08
2.7
0.8
27
8
,
Tetrachloroethylene
1,2-(transtdichloroethylene
2,700b
270b
27c
aASsumes consumption of 2 liters of drinking water per day over a 70-year period. Prom
References 1, 2, and 3.
bMemorandum from William N. Hedeman, Jr., Director,' Office of Emergency and Remedial
Response, to Lee M. Thomas, Acting Asst. Administrator, Office of Solid Waste and
Emergency Response, dated April 2, 1983.
cTacoma-Pierce County Health Department, Washington.
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The Tacoma-Pierce COunty .ealth D!partment has established target values
for these contaminants a t the 10-6 1 evel for suspected carc ;nogens and
at 27 ppb for l,2(trans)dichloroethylene. Based on these thresholds,
untreated water from Wells H-l and H-2 is consi dered a threat to human
heal th if used for drinki ng water.
The greatest contamination has been found at 85-95 feet belolll the
surface~ A plume of the solvents extends from Plaza Cleaners southeast to
Wells H-l and H-2, several hundred feet away. However, regional
groundwater flow is to the northwest. Since H-l and H-2 have not been
pumping (except for a few days) for several years, it is 1 ikely that a
plume also extends northwest of Plaza Cleaners. The extent of this plume
and the levels of contamination are unknown, as there are no monitoring
wells in that direction. COnstruction of those wells will be a part of a
future remedial investigation.
In the illl11ediate vicinity of the Ponders well field, a perched aquifer is
usuall y present in Stei 1 acoom gravel s above a 1 ayer of rel ativel y
impenneable Vashon till. The.lateral extent and thickness of this till
layer are unknown in the area. 91allow well s typically tap thi s aquifer.
However, advance outwash deposits, with an average thickness of about 100
feet, are the most productive aquifers. Well s H-l and H-2 tap water .from
the advance outwash deposits. .
The surface so11 is very penneable. In addition, there appears to be a
condui t between the shallow groundwater and the deeper aquifer tapped by ..
H-l and H-2, as the contaminated wells are only a few hundred feet from
the suspected source. Indications are that there is some form of well or
gravel pitat the tenninus of the septic tank drainfieldwhich allowed
contaminated effluent to directly reach the lower aquifer. This will be
veri fi ed in the remedial i nvesti gati on. .
.
~proximately 600 customers are nonnally served by Well s H-l and H-2.
Water is now being pumped from other parts of Lakewood Water District's
system to serve these people. H:»wever, the pressure is too low to provide
adequate fire protection and conservation measures have been put into
effect. Also, with heavier pumping of other Lakewood well s, and with H-l
and H-2 shut down, it is possible the contamination is flowing towards the
other wells in the system. Therefore, the problem,left unsolved, could
eventually affect the remaining 13,000 customers in the Wa ter Di stri ct.
D.
Enforcement
Thus far, on" the 1»1 aza Cl eaners at 12509 Paci fic Hi (jIway SW in Lakewood
has been identified as a potentiany responsible party. DJrfng the
remedial investigation it is likely that a few additional monitoring wells
will be constructed to detennine if other responsibl e parties exist.
Virtually a 11 COlll1ler'C fal and resi dentfal bun dings in Lakewood use septic
tanks, and f tis conceivabl e that one or more additional (though probably
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The only enforcement action talcen by EPA thus far has been the issuance of
CEJl:LA notice letters to the'fonner and p~esent owners of Plaza Cteaners.
WDOE issued an administrative order and s 19ned a sti pulated agreement
(discussed previously) wi th the owners. \tIen the site was turned back to
EPA for action, EPA Headquarters, in consul tation with WDOE, detennined
that Fund money would be used for the completion of the Remedial
Investigation/Feasibility Study. The Region will decide at a later date
whether to attempt cost-recovery.
E. Al ternatives Evaluation
The objectives of the proposed project are as follows:
1. Restrict the spread of contamination in the aquifer to reduce
ultimate clean-up needs and to protect the quality of water supply from
other well s.
2. Restore full water service to the area of the Lakewood Water
Dfstrict tnat is adVersely affected by the shutdown of Wells H-l and H-2.
This includes restoration of nonnal system pressure, flow, and
f i re-fi ghti ng capabi 1 i ty .
3. . Facilities to meet these objectives should be operating at the
earliest ~actica1 date, preferably to meet the 1984 peak demand. -.
A treatment facil ity on the combined well output is proposed to meet these
objectives. 1hi s facil ity wou1 d be operated to puri fy the well water to
. dri nk i ng water requirements, sized to provi de the 'requi re d c apaci ty and
throughput, and operated year-round to control the 'spread of aquifer.
contamination. .
Nontreatment alternatives such as developing other wells or booster pumps
on the existi ng system will not meet the project objectives. Nei ther of
theseap~oaches would 1 imit the spread of contamination and both could
aggravate the problem by drawi ng the contamination toward the operating
wells. Locating and developing new wells coul d not be compl eted to meet
the schedul e objective. A booster pump on another part of the system
would have to produce hij1er than nonnal operating pressure to deliver the
required flows. A detailed distribution system study woul d be needed to
veri'y the technical acceptability of thi s approach. Such a study,
desi gn, and installation coul d not be completed in time to meet the
schedule objective. For these reasons, nontreatment alternatives are not
acceptab 1 e. I ..
The treatment system perlonnance cri teri a are as follows:
Water 9.lpply. Well s H-l and H-2 have existed for years in the system, are
located in the same fenced site, have demonstrated capacity to meet the
system's pressure and flow requirements, and are the production well s
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for a treatment facility. Operation of these wells will therefore meet
the District's water supply requirements and will provide the best
availabl e means to limi t further contaminant spread.
l,2-(trans)dichloroethylene
Tri ch 1 oroe thyl en e
Te trach 1 oroethy 1 ene
27
2.7
0.8
ppb
ppb
ppb
Treatment Capacity. Mr. R. Forster, superintendent of the Lakewood Water
Di stri ct, indicated that hi stori cal operation of the system with Well H-l
produci ng 1 ,200 gpm an dWell H -2 produci ng 800 gpm for a total of 2,000
gpm would meet the system's peak requirements.
Pumping Plan. 'This criterion-is included to provide a basis for comparing
the elements of different system alternatives that depend on the amount of
. water processed; for example, pumping costs and carbon consumption. The
numbers chosen are based on recent hi stori cal data for the three peak
sumer months to supply adequate water to the residents plus a .
contingency, and on a base flow rate of 1,000 gpm during the rest of the
year to restrain contamination spread. ,ennual treated volume on this - .
basis would be 590 million gallons.
.
Treatment Facil ity Life. A treatment facility capabl e of meeti ng the .
water supply and contamination control objectives is needed until a
long-range, fi na 1 remedia 1 action (RA) is effective. The remedia 1
investigation/feasibility study assignment has just been made and is
expected to require about a year to complete. .authorization and design of
a final RA can be expected to require 6 months or more and construction,
another 6 months to a year. A short-tenn life of 3 years was therefore
sel ected for economi c eval uati ons.
It is also possible that the facilities being considered in this study
will become part of the long-tenn RA and be required to operate for
several additional years. A desi~ life of 15 years was therefore
selected for the facilities, and operations and maintenance costs were
developed for this longer period.
Treatment altynati.ves considered for thi s project are:
. No action
.
Conventional coagulation, sedimentation, and filtration
Reverse osmosi s
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.
Ion exchange
Steam stri pping
.
.
Biological treatment
Ac tivated carbon fH tration
.
.
Aeration
No Action. The no-action alternative would involve no treatment
fac11ities and ei ther not operati ng the well s or operati ng them into the
system or to waste.
No t operating the well s is an unacceptabl e alternative because thi s course
woul d no t mee t the water suppl y or contami nation confi nement projec t
objectives. The existing threats to public health and welfare through
inadequate water supply and the potential for future contamination of now
clean wells would continue.
Operating the well s into the potabl e water system wi thout treatment is.
unacceptable on the basis of the resulting threat to public health. Such ~
action would result in dri nking water contamination at 1 evels exceeding
the accepted criteri a for the speci fi c contami nants present by factors
between about 13 to 300. Operating the wells to waste would 1 imit the' ..
further spread of contamination but woul d not protect the publi cheal th
,and wel fare, whi ch woul d require restoration of a n adequate water suppl y.
Of scharge of untreated water to waste woul d create an added potential
threat to pUblic health and the environment in open waterways. WDOE,
responsibl e for such di scharges, has advised tha t some degree of treatment
and an NPDES pennit would be required for routine discharge to waste from
these wells. (])taining such a pennit would require several months. This
alternative is therefore unacceptable on the basis of inadequate
protection of public heal th and welfare, potential threat of contamination
to a wider area of surface waters and the population, and the inability to
respond qui ckl y to mi ti gate the existi ng problems.
Conventional Wa ter Treatment, consisting of chemical addition to coagulate
coll01dal mater1al, sed1mentation to partially separate the coagulated
material, and filtration to polish the treated water, is used to purify
many sround and surface water supplies. This process is not effective in
removing the organic sol vents found in Ponders Corner well water. The
solvents woul« rema1 n in solution and pass through such a treatment
system. Thi s f s therefore not a suitable treatment technology for thi s
application.
Reverse Osmosis (RO) can be used to separate dissolved' materi a15 in
water. In thi s process pressure is used to force water through a
semipenneable membrane that allows the passage of water molecules but
-------
arranged in series to achieve higher degrees of purity than for a single
stage. Membrane processes are somewhat imperfect with respect to organic
separations, so the produced water woul d still contai n some organi cs.
.-.
Pretreatment requirements for reverse osmosis are substantial. capital
costs are hi gh, and requ ired operati ng pressures are hi gh.. For these
reasons, reverse osmosis is not considered a suitable treatment process
for thi s application.
Ion Exchange is an accepted method for removi ng ions from water. Ion
exchange is comonly used to reduce the hardness in water and to remove
specific metals. Only charged particles in solution or contaminants that
are reactive wi th the resi n can be removed by ion exchange. The feedwater
is passed throug, a bed of resin material, which is typicall1in the form
of small beads, that exchanges ions wi th those of the contam1nant 1 n
solution.
Ion exchange would be ineffective in purifying the Ponders Corner well
water because the contaminants do not produce ions in solution and will
not react with a resin.
{~e::i;;~~P~~gW::~;dt~:;~~:;U~~i~ii~~ ~::a;~e ~~::~~:n~ nC:fi ~;l~t~:r
water woul d then be needed before'u se in the water system. Thi s process
is typically used in combination with a boiler plant where steam is
produced for some other purpose, and the stri pp1ng operation adds a small -
cost increment. For this application, the facilities and fuel costs would
. be very hig" and it is therefore not a suitable alternative.
Biological Treatment has been applied on a limited scale to the cleanup of
severaf"C'O"ntaminated groundwater resources. Specially developed bacteri a
are cultivated to feed on the specific contaminants in situ or in surface
reactors. These processes are typically proprietary and require pilot
work and development of the bacterium strai n. Experience to date has been
with small systems operating at a few gallons per minute. They appear to
offer a low
-------
ktivated Carbon Filtration is an existing, conventional water treatment
technology ifii"t will remove the organic solvents present in these wells.
lhi s technology involves the adsof1)tion of the contaminants on the surface
area of carbon particles. The feedwater is passed throug, a bed of carbon
as in a conventional sand filter. Ei ther pressurized 'or gravity tanks may
be used. A gravi ty system requires repumping the treated ~ater to
discharge into the distribution system. For carbon adsof1)tion treatment
to produce potable water, a second or lag unit usually operates in series
with the primary or lead carbon unit. Carbon treatment systems arranged
in this fashion allow the lag carbon vessels to protect against
contaminants passi ng into the water system when their carbon is exhausted
and can no longer adsorb the contaminants. This arrangement also enables
continuous operation of the treatment system when carbon is exhausted and
must be repl aced.
Several carbon system suppliers have treatment uni ts for 1 ease or purchase
that would meet the performance requirements of this proposed treatment.
facility. Depending on the specific design and availability of units,
installation and startup can be accompl ished on a short schedul e that
could probably meet this project's needs.
ktivated carbon fil tration can therefore be considered further in the
more detal1edevaluation of potentially suitable alternatives.
Air Stripping is the technology selected in early 1983 by EPA to treat the"
well water from the Ci ty of Tacoma's Well 12A. Well 12A is contaminated
by several organi c solvents includi ng those found in the Ponders Corner
wells. Air stri pping is a well established technology in which the
contaminated feedwater i5 distributed over the top of a 1005,ly packed
f111 material in a tower. As the water cascades down through the packing,
it breaks up into small droplets that provide a 1 arge surface area for.
mass transfer. Air is forced throug, the packing from the tower base, and.
vol atil e organi cs transfer from the water to the air a t the a i r/water
i ntertace. The treated water is collected in a wet well below the tower,
chlorinated, and pumped into the distribution system.
.
Air stripping can therefore be considered further in the more detailed
evaluation of potentially suitibl e alternatives.
It is analyzed below, along with a carbon adsorption treatment system.
CARBON ADSORPTION TREAMNT SYSTEM
" ..
The preliminary design of the carbon adsorption system for the Ponders.
Corner well s is based on the desi gn criteri a of 2 to 4 gallons per minute
per square foot and 30 minutes empty bed contact time. The system is a 150
desi ~ed for lead-lag operation as described above. ttldraulically, the
system will produce up to a maximum output of 2,000 gallons per minute.
Contaminant loading to the carbon system was based upon an approximate
yearly average flow rate of 1.62 mgd and estimated average contaminant
concentrations of 2501)pb tetrachloroett1Ylene, 360-ppb
-------
Ictual carbon consumption is best detennined from treatability tests. In
the absence of this infonnation, carbon consumption can be estimated from
adsorp ti on data in the 1 i terature. There was no i nfonnati on found in the
l1terature on the adsorption of the two major compounds when both are the
only contaminants present in water. Therefore, estimates of their
adsorption characteristics were made from data on the adsorption of these
compounds alone and with one or both compounds in the presence of other
simil ar compounds a t the same concentrati on s as in the Ponders Corners
well water. A carbon consumption rate of 0.4 pound per 1,000 gallons was
estimated.
To satisfy the stated design cri teri a for the system characteri stics at
Ponders Corner and to provide for lead-lag operation of the carbon
vessels, twelve 1 O-foot-d iameter vessels with 12-foot-deep carbon beds
would be required. lhese twelve vessels would be arranged in two sets of
six parallel vessels in series..
Treated water from the carbon vessel s woul d discharge into a wet well.
From the we t well, the water \lioul d be pumped and di scharged to the
Lakewood distribution system. The discharge from the wet well would be
chlorinated for disinfection. A process flow diagram of the carbon
treatment system is shown in Figure 4.
Both gravity and pressure carbon systems were evaluated and cost estimates
prepared. The cost of the carbon system components were based on
1 nfonnation obtained from carbon vendors. The resul ts of the cost
estimates show that a treatment system employing a pressure or gravi ty
carbon system were approximatel y the same in cost.. Based on thi s
evaluation and cost comparison, final costs are presented for a gravity
carbon treatmen t system becaus e it prov; de s more operati ona 1 fl exi bi 11 ty.
Ei ther a gravity or pressure system would be capable of producing water
that meets the required water quality criteria. The expected discharge
concentrations are shown in Table 3.
A summary of these treatment system costs is given in Tabl es 4 to 6. The
basi s for these costs is discussed below.
The treated water from the carbon system will discharge into a wet well
before bei ng pumped into Lakewood I s dis tribution system. The requ ired
size of the wet well is estimated to be approximately 4,000 to 5,000
gallons. For estimati ng purposes, a concrete wet well was assumed.
The wet-well pump sizing was based on a maximum flowrate of 2,000 gpm, an
average flowrl'te ot 1,000 gpm, and a di scharge pressure 0 f approximatel y
65 pounds per square inch. These design values are pr.el1minary and were
used for developing a cost estimate only. The pumping system cost
estimate was based on three vertical, 3-stage turbine pumps each sized to
deliver 1,000 gpm at 65 pounds per square inch, wi th 50 hp motors. o,e of
-------
PlOWMETEft .
TO
NO WELL
'LOWUE1B
TO
H2
EXISTING WELL
8 CARBON GRAVITY
VESSJ=t S .. PARAUEl
-.
-
SAMPLE
TAP
(TYPICAlJ
CHlORINE
ADDITION
SAMPlE
TAP
TO
DISTAl
SYSTEM
FIGURE 4
PONDERS CORNER
. PREUMINARY FLOW DIAGRAM ~,
CARBON ADSORPTION SYSTEM
-~r
'.
-------
Table 3
PONDERS CORNER
ESTIMATED CARBON SYSTEM PERFORMANCE
Influent Effluent
Concentration Concentration Criteria
(ppb) (ppb) (ppb)
Tetrachloroethylene 250 ND 0.8
l,2-(Trans) Dichloroethyene 360 ND 27
Trichloroethylene 40 NO 2.7
ND--Concentrations less than the lower limit of. detection of 0.2 ppb
for tetrachloroethylene and trichloroethylene and 5 ppb for
1,2-(trans)dichloroethyiene.
.
.
-------
[ '.
I'
I
f
Table 4
PONDERS CORNER ACTIVATED CARBON SYSTEM
CAPITAL COSTS
Procurement
(Thous. $)
Carbon Vessels
Carbon Media
Wet Well
Relift Pumps
Chlorination
Subtotal
525
100
11
14
6
I-
I
656
423
Construction
Procurment and Construction
Subtotal
1,079
Professional Services
108
Total
1,187
Continqencies
Procurement (20t)
Construction (20t)
Professional Services (1St)
131
85
16
232
Subtotal
Estimated Pro?ect Budqet
1,419
,
_.
-------
"
Table 5
PONDERS CORNER ACTIVATED CARBON SYSTEM
O&M COSTS
Labor
($/year)
6,700
Operator & Maintenance
Supervisor/Administration
7,200
Expenses
Power
39,000
224,000
1,000
8,500
2,500 . ~
288,900
Carbon
Chemicals
Lab Tests
Vehicle
Estimated Annual O&M Costs
Notes:
I
.
Power costs assume $0.034/kWh.
Carbon replacement costs assume $l/lb c~rbon.
Labor costs assume $16/hour.
Supervision/administration costs assume $50 per hour.
Laboratory tests assume one set of samples per week,.
four samples per set, $40 per sample.
Chemical costs are for chlorine at $0.25 per pound.
-------
Table 6
PONDERS CORNER ACTIVATED CARBON SYSTEM
PRESENT WORTH COSTS
Project Construction Costs
Annual O&M Costs
First Year Total
3-Year Present Worth
Construction
Salvaqe
Present Worth O&M Costs--3 Years
TOTAL
1S-Year Present Worth
Construction
Salvaqe
Present Worth O&M Costs--1S Years
TOTAL
Notes:
Salvaqe value for carbon vessels, pumps, and
chlorination system only; straight-line de-
preciation over 1S years assumed.
Annual costs were discounted at 10 percent.
,
(Thous. $)
1,419
289
1,708
1,419
(436)
718
1,701
1,419
o
2,198
3,717
-------
The cost estimate ihcludes a chlorination system to disinfect the
discharge from the wet well. A chlori ne residual of 0.2 ppm is required.
For desi gn purposes. a chlorine dosage of 1 ppm was assumed. The cost
estimate is for a ch 1 ori nati on system that will deliver up to 30-pounds
per day of chlorine wi th a 10 to 1 turn~own rati o. .The system includes
scales for two 1 50-pound chlorine cylinders. an injector. and controls to
proportion chlorine dosage wi th flowrate.
Construction costs for Ponders Corner were based on the construction costs
for the Tacoma Well 12-A project. Construction costs for Ponders Corner
were assumed to be the same percentage of procurement costs as for the
Well 12-A project. Thi s method was judged to be a vali d approach based on
the similar level of complexity of the two projects. Costs for piping.
valves. electrical. and instrumentation and control s are included in the
construction costs.
Professional services include: design and procurement completion;
approval and change coordination; penn1ts. site access. and agency
. coordination; construction and subcontract administration; overall
management. control. and reporti ng; cOllll1unity relations support; and other
related expenses. These costs were estimated from experience with the
Well 12-A project. Because the carbon system and air stripping system
have similar complexity. professional services costs were assumeq to be
the same for both systems.
Contingencies of 20 percent for the procurement and construction phases 'of.
the project and 15 percent for professional services were used. .
Contingencies for the carbon system are hi~er than those used for the air
strippi ng system due to. a lesser degree of detai 1 in the estimate.
.
Yearly operation and maintenance costs include carbon replacement. power.
laboratory. and labor costs. Carbon replacement costs were based on an
estimated consumption rate of 0.4 pound per 1.000 gallons. Based on a
yearly average flow of 1.62 mgd. approximately 224.000 pounds of carbon
. are required per year. A carbon replacement cost. including supply.
regeneration. and disposal services. was quoted by a carbon vendor at
$1.00 per pound.
Power costs were based on an average discharge flow rate of 1.500 gpm for
3 months of the year and 1.000 .gpm for the remaini ng 9 months. It was
assumed that two 5O-hp rel1ft pumps and the lSo-hp well pump would be
requ ired to provide 1.500 gpm. O1e 50-hp pump and the 100-hp well pump
would be required to provide 1.000 gpm. A power cost of $0.034 per kWh
was assumed. I . .
Labor costs assumed 8 hours of operation and maintenance per week for 52
weeks at a labor rate of $16 per hour. Yehicl e costs of $6 per hour for
the same number of hours per week were also assumed. Supervision and
-------
The annual cost for operation and maintenance (0,,",) of the carbon
treatment facilities only is estimated at $273,300. Q&M of the wells is
estimated at $15,580 a year. .
AIR STR I PP ING TRE A lME NT SYST EM
The preliminary design of the air stri pping system for Ponders Corner is
based in large part on the pilot work perlonned for the Tacoma Well l2-A
project. From this pilot work and review of the literature, it has been
found that gas-to-liqui d ratios of 200 to 300-to-l on a volume basis will
achieve the removal rates of chlorinated organic solvents necessary to
produce potabl e water from the groundwaters a t Ponders Corner and Well
12-A. Mass transfer coefficients were developed from a model in the
literature that was successfully used in the design of the Well l2-A air
s tri ppi ng sys tern.
The air stri pping conceptual design for Ponders Corner was based upon
tetrachloroett1)tlene, which is. the most difficult contaminant to remove.
The other contaminants would be removed to 1 evels below the design
effluent crite,.; a. Tab1 e 7 shows the estimated tower perlonnance for the
contaminants present.
TABlE 7
RJNOERS CDRNER AIR STRIPP ING SYSTEM
EST IMATED TO~R PERFOR*~E
1111 tfa 1 Fi na 1 Des; gn
Concentration Concentra ti on Cri teri a
(p pb) . (ppb) (p pb)
Te trach1 oroe tI1Yl ene 250 Les s tha n 0.8 0.8
l,2-CTrans)dich1e>-
roethy 1 ene 360 NO 27
Tn chl oroe tt1)tl ene 40 NO 2.7
ND--Less than 1 ower 11mit of detection of 0.2 ppb
for trfchloroettf(lene and 5.0 ppb for
1.2-Ctrans)dichloroethylene.
,
-
The preliminary design of the air str1 ppfng system calls for two stri ppfng
towers 1 n parallel, each capab1 e of treatf ng 1,000 ga11 ons per minute for
a total treatment capacity of 2,000 gallons per minute. Each tower would
-------
Treated water from the strippi ng towers woul d discharge into a wet well.
From the, wet well the water would be pumped into the Lakewood distribution
system. Of scharge from the wet well woul d be chlorinated for
disinfection. A process flow diagram of the treatment system is showff in
Fi gure 5.
A summary of the costs for the air stripping treatment system is given in
Tables 8 to 10. A discussion on the development of these costs is given
below. Because of the s imilari ty ins he of the Tacoma Well 12-A
stripping towers, costs from the 12-A project were used as a basis for
some of the costs developed for Ponders Corner.
..;
Each of the two air stripping towers would be 12 feet ,in diameter with a
packing depth of approximately 25 feet. The overall tower height to the
top of the discharge stack would be approximately 55 feet but may vary,
depending on the hei~t of the stack and final design considerations.
rDsts for the tower shell s were based on the tower costs for the Tacoma
Well 12-A project. Towers for the Well 12-A project are 12 feet in
diameter wi th an overall hei gAt of approximatel y 50 feet. Pdjustments
were made for the greater packing depth required at Ponders Corner, the
possibl e need for an intennediate medi a support plate, and inflation.
Each tower would require approximately 2,700 cubic feet of media. Several ~
media suppliers were contacted, an'd 'cost infonnation varying from
apJl"'oximately $8.00 to $13.50 per cubic foot was received. For purposes- ..
of this cost estimate, the hig,er price quote was used.
.
One fan for each s tri pping tower woul d be required. The fans were shed
for an a ir flow rate of 27,000 cubi c feet per minute and a pressure drop
of 10 inches of water. The power requirement for each fan at these
operati ng criteri a, assumi ng 70 percent efficiency fans, is 60 hp. Cost
for the fans includes silencers, and was based on a fan vendor's
i nfonnation.
As with the carbon adsoJ'1)tion system, this system will require a wet well
and pumps for di scharge to the Lakewood distribution system. These items
will be the same size and capacity as they were for the carbon system.
'The wet well volume waul d be 4,000 to 5,000 gallons. Pump cos'ts were
based on three vertical turbine pumps, each rated at 1,000 gallons per
minute, and I di scharge pressure of 65 pounds per square inch. O1e of the
three pumps would serve IS a standby.
A chlorination system for treated water dfsi nfection is also included in
the cost. It"woul cf have the same clplci ty and components as the
chlorination system for the carbon' treatment system. :
A chlorine solution would be cycled throu~ the towers periodically to
clean the packing. 'The cost of this system is included in the
-------
FUMMETER
10 DRAIN
I
(asTING WELL
10 DRAIN
~WEU.
Tt 8'~PINO
rowER
T2 SmiPPINQ
. TOWER
lit
..
SILENCER (TYPICAlJ .
CHlOfltE
ADDmON
10 DRAIN
WET WEll
FIGURE 5
PONDERS CORNER
PREUMINARY FLOW DIAGRAM
. AIR STRIPPING SYSTEM
10
SYSTEM
. .
I .
-------
-
- --
.------------ -..-
Table 8
PONDERS CORNER AIR STRIPPING SYSTEM
CAPITAL COSTS
Procurement
Towers
Media
Fans/Silencers
Wet Well
Relift Pumps
Chlorination
Subtotal
Construction
Procurement and Construction
Subtotal
Professional Services
Total
Continqencies
Procurement (10%)
Construction (15')
Professional Services (15%)
Subtotal
~iminar~ Estimated
Pro:1ect Bu qet
,
(Thous. $)
86.5
86.5
21.0
10.7
13.8
, 6.5.
225.0
145.0
370.0
108.0
478.0
22.5
21.7
16.2
-
60.4
-------
Table 9
PONDERS CORNERS AIR STRIPPING SYSTEM
O&M COSTS
Labor
Opera~or & Maintenance
Supervisor/Adminis~ra~ion
($/year)
6,700
7,200
Expenses
Power
Chem.i.cal~
Labora~ory
Vehicle
Tes~s
!6,OOO
1,000
8,500
2,500
81,900
Es~imated Annual O&M Costs
Notes:
Power cos~s assume $0-.034/kWh.
Chemic~l cos~s are for chlorine at $0.25/pound.
O&M labor cos~s assume $16/hour, Supervisor/Admin. .
at $50/hour.
Vehicle costs assume $6/hour.
Laboratory tes~s assume one set of samples per
week, four samples per set, $40 per sample.
-------
."
Table 10
PONDERS CORNER AIR STRIPPING SYSTEM
PRESENT WORTH COSTS
(Thous. $)
Projec~ Construction Cost
Annual O&M Costs
First Year Total
540
82
622
3-Year Present Worth
.
Construction
Salvaqe
Present Worth O&M Costs--3 Years
540
(171)
203
-
TOTAL
572
15-Year Present Worth
Construction
Salvaqe
Present Worth O&M Costs--15 Years
540
o
623
TOTAL
1,163
Note,:
Salvaqe value for towers, media, pumps, fans, and
chlorination system assumed usinq straiqht-line
depreciation.
Annual costs were discounted at 10 percent.
-------
Construction costs are based on the construction costs for the Tacoma Well
12-A installation. Professional services costs were also estimated from
the Tacoma Well 12-A project. Contingencies of 10 percent for procurement
and lS percent for construction and professional services were used.
Operating and maintenance costs for the air stripping system are the same
as the OIM costs for the carbon system except tha t carbon replacement is
not required and there is an additional cost for air blower power (two
blowers at 60 hp each for 3 month s, one blower at 60 hp for 9 month s) .
Annual operations and maintenance costs for the air stripping treatment
facilities only are estimated at $66,320. OIM costs for well s only are
estimated at $15,580 a year.
F.
Collll1unity ~lations
Documents made ava;1able for public conunent included:
IlFocused Feasibil ity Study: Ponders Corner Well Water Treatment
Fa c 11 i ty, La Icewood, Wa shi ng ton, II May 1984.
lI~dfal fetion Mlster Plan: Lalcewood Water District Wells,
La Icewood Wa shi ng ton, II November 7, 1983.
IlReport of the Q-oundwater Investi gation: . Lalcewood, Washi ngton,
October 1981 to February 1983,11 February 1983.
II Fac t 91ee t:
Ponder s Corner Well Water Treatment Facil i ty ,II May 1984.
The Focused Feasibil ity Study; s the document we sought cOfllnents on.
others were provi ded for background.
The public was notified of the pUblic comment period, extending from May 7
to May 21, 1984 through several channel s. The Lakewood Press, a local
paper distributed to all Lakewood residents, was provided ;nfonnat;on for
a story on the proposal in hte April. On May 3,1984 EPA issued a press
release discussing the proposed initial remedial measure and announcing
the publi c meeti ng. A story wa s subsequentl y run in the Tacoma
News- Tri bune (the Tacoma area's 1 argest daily newspaper). Al so, several
local radio stations ran a story on the wells and announced the meeting.
The
EPAls contractor, CHzM Hill, prepared a cOIIIIIunity relations plan for
this project. As part of that effort a mailing 1 1st of over 60 persons.
having an intfrest 'n the project was developed. The press release and
fact sheet were mailed to those 60. i ndivi duals on May 3, 1984.
The public meeting was held at 7:00 p.m. at the Lakewood Branch of the
Pi eree County L1 brary. Two TV stations and one radio station had crews
present and ran subsequent stories in the Seattle and Tacoma areas. Also
in attendance were representatives from WDOE, Tacoma-Pi eree County Health
[)!partment, Lakewood Water District, Tahomans for a ~althy Environment, a
Pieree County Council member, the owner of Plaza Cleaners and his
-------
The comments were generally supportive. Some concern was expressed about
spending additional money at the site for further investigations. and
questions were asked regarding who was going to pay for the project. Some
speculation was given on other potential sources. A Collll1unity Relations
Responsiveness SUllll1ary is a 150 attached.
G.
Consistency wi th other £nvironmental Laws
Both the activated carbon system and the air strippi ng system al ternatives
would be in compliance with all environmental 1 aws and regulations. The
only environmental law or regulation applicabl e to the activated carbon
system would be the Resource Conservation and Recovery Act regulations
deal i ng wi th the handli ng and di sposa 1 of hazardou s wastes. The carbon
would periodically be removed from the system and replaced with clean
carbon. The used carbon woul d contai n hi gh amounts of hazardous
materi al s. namely the th ree sol vents absorbed from the well water. The
carbon would be disposed of at an EPA approved landfill. incinerated. or.
regenerated by an approved finn.
The only environmental law or regulation applicable to the air stripping
system woul d be O:cupational Safety and ~al th 1dministration (09iA) .
8-hour ground 1 evel a ir standard s. L1 sted below are estimates of the.
8-hour average levels of contaminants at ~ound level. emanating from the ~
towers.
Estimated 8 09iA8 - .
Contami na n t fobur Average fob ur Standa rd
1.2 Transdichloroethylene 9.1 p~ 200.000 ppb
Tn chl oroe tt1Yl ene 0.8 ppb 100.000 ppb
Te trach 1 oro e thy 1 ene 3. 7 p~ 100.000 ppb
())viously the contamination level s will only reach a small fraction of the
09iA standard. An a ir emission pennit woul d be obtai ned from the Puget
Sound Air Pollution Control Igency.
RecOlllllended Al ternative
SoU1 an activated carbon system and an air stripping system are
technicall y acceptabl e and have substantia 1 pas t operati ng experience.
Ei U1er system. properly designed and operated. would produce treated water
wi thi n U1e prescribed 11mi ts. The treated water from a carbon system
would have residual contaminants in the nondetectable range. and treated
water from an4ir S'tripping system would have residual contaminents at .or
below the established limits.
An environmental concern wiU1 a carbon system is the possible spread of
contaminated carbon dun ng the frequent cycles of handling. transport. and
offsite regeneration that would be required. Fully contained piping
-------
transport. These systems are used extensively and will nonnallyeliminate
spill s. 910ul d a spill occur, the contamination will spread only wi th the
carbon since it is bound into the carbon by the a dsorp ti on process.
C1eanup of such an event woul d be accomplished by recoveri ng the carbon,
and the hazard to the popul ation and workers woul d be low.
Environmental concerns with an air stripping system are the spread of
contaminants throug, the air discharge and objectionable noise from the
fans. Fan inlet silencers will effectively eliminate any increase in
noise levels at this site, as indicated by the experience of the EPAls
Well 12A facility in Tacoma. Calculations and tests on the 12A air
stripping system showed negligible, nonmeasurable air and ground-level
concentrations of contami nents. The tower air f1 ow for the Well 12A
system and the proposed air s tri ppi ng system for Ponders Corner are almost
identical, and the expected contamination level s at Ponders Corner are
about 75 perc ent of the desi gn loading ,basis a t Well 12A. For these
reasons, ground-level concentrations of contaminants similar to Well 12A
waul d be expected for Ponders.Corner.
Both systems are capable of being implemented in a short time; the
schedule and startup date would be controlled 1 argely by the ability to
maintain continuity during design, procurement, and construction.
The cost of a carbon system is estimated to be substantially greater than.
for an air stripping system. Cost comparisons developed in this study are
shown i n Tab 1 ell. .
c
, Table 11
SYSTEM COMPARATIVE COSTS
('Thousands S)
Firs t Cas t
Annual 0 & M
First Year Total
3- Ye ar Pre sent Worth
15- Yea r Presen t Worth
Ca rbo n
1 ,41 9
289
1 ,708
1,701
3,717
Air
Stri ppi ng
540
82
622
572
1,163
On the basis of these compari sons and the substanti al cost di fference that
exists between these two systems, it is reconmended that the air stripping
system be sel'=ted because it is technically sound, environmentally,'
acceptable, and the most cost~ffectfve solutfon for thf s project. Afr
stripping fs the most cost-effective alternative whether the towers are fn
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H. Operation and Mainten~nte (0 & M)
o & M costs for the air stripping system are discussed above in the ~arbon
Adsorption Treatment System and the Air Stripping Treatment System
su~parts of the Alternatives Evaluation. The annual 0 & M cost is
estimated at $82,000.
Negotiations with the State on 0 & M funding are almost complete. For t~e
'. first year of operation the Lakewood Water District has agreed to pay the
o & M costs it would ~ave to pay to operate the wells if they were not
contaminated. This amounts to approximately $15,580. This money would
come from fees collected to supply the water to its customers. The
Washington Department of Ecology has agreed to pay 10' of the remaining 0
& M costs for the first year out of the State's Superfund. The Lakewoo~
Water District will seek a rate increase to cover 100' of 0 & M costs for
all succeeding years.
Ownership of t~e treatment system, ~nd liability on the site, is ~ein9
worke~ out in a separate agreement with the Lakewood Water District and
WDOE. The system will ~e located on lakewood Water District property.
, I.
Schedule
Some key milestones and approximate dates ,for project implementation are
11 sted below.
Mil estone
Complete 'Enforcement Negotiations
- .
Target Date
Upon completion of RI/FS
Approve Initial Remedial Action
(signs ROD)
May 31. , 984
Award Superfund State Contract for
Design and Construction
Complete Design
May 31, 1 984
Award Cooperative Agreement for OIH
Start Construction
June 1 2, 1984
August 15, 1934
,
June 1 3, 1934
August 31, 1984 (one tower
operational August 1,1984)
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J.
Future Actions
An obligation of Fund monies has been made to complete a full RIfFS
. beginning summer 1984. A scope of work has been approved and' CH2M Hill
will begin working on the work plan by June. The remedial investigation
will likely include the construction of several additional ~onitoring
.' wells to determine if any other sources of contamination exist in the
arel1, and to find out how far the contaminant plume "0''1 extends. Since
Wells H-l and H-Z have been shut down, it is believed the contamination
has been flowing in a different direction. This information is importartt
in designing a final remedial action for the well contaminl1tion problem.
In addition, more work is proposed for the Plaza Clea"ers site to
determine if it is a continuing source of contamination. Specifically,
soil samples ~ill be taken and an investigation of the septic tank
drainfield is planned. The drainfield, and suspected well at the end of
it, have never been found. The soil in the area of the dr!infield I1"d
well may remain contaminated, even thQugh no solvents now enter the septic
tanks.
Following th3t investigation, a feasibility study ~ill be prepared,
assessing various options for remedying the situation. The same process
outlined in t:oJis Record of Decision will likely be used to select t"e
alternative to be implemented. Negotiations with responsible parties on
impleme"ting the remedi~l action may tal#.
. . .
',.
,
Hazardous W
Information k
US EP A Reglo
Philadelphla~ II
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