i b o o o o o o aJOHNSON & MALHOTRA,P.C.ENVIRONMENTAL ENGINEERS

—^April 17, 1989 EPA Region 5 Records Ctr.

243546Mr. Michael YangRemedial Project ManagerU.b1. Environmental Protection Agency230 S. Dearborn StreetChicago, IL 60604

Subject: Technical Memoranda For Field ActivitiesHunts Disposal Landfill SiteRacine County, Wisconsin

Work Assignment No.: 2-5L3DEPA Contract No.: 68-01-7403Document No.: 002-CCJM-EP-4035-0

Dear Mr. Yang:

The REM V team is pleased to submit the technical memoranda forfield activities performed at the Hunts Disposal Landfill Sitelocated in Racine County, Wisconsin. A memorandum has beenincluded for each field task performed during the period fromDecember 1988 through early March 1989.

The technical memoranda have been provided to inform you of theactivities conducted at the site. They contain details of thescope of each task, the methods utilized, and sampling locations.The memoranda are in the same format that will be utilized for theRemedial Investigation (RI) Report and are intended to be useddirectly in the Draft RI . The use of this format for the memorandaallows you to see what the RI format will be like, review andprovide com-ments arid results in cost and time savings for theoverall project.

Enclosed are Sections 3, 4, 5, 6, 7 and 9. Additional sectionswill be prepared after the remaining field work is performed. Weare currently mobilizing to complete the remaining field tasks andthe second round of sampling. We plan to be at the site on April24, 1989 for a duration of approximately one month.

If you have any questions or comments, please contact me.

Very truly yours,

C. C. JOHNSON & MALHOTRA, P.C.

Sidney F. Paige, D . Env . MPHSite Manager

SFP:sth

Enclosure

cc : KileWRJ-Washington, D.C.CCJM-Chicago, ILCCJM-Silver Spring, MDDocument Control

200 WEST ADAMS STREET • SUITE 1601 • CHICAGO. ILLINOIS 60606 • (312)621-3944

3.0 SURFICIAL SOIL INVESTIGATION

3.1 PURPOSE AND SCOPE

Soil samples were collected from the surface of the landfill andsurrounding areas to determine the extent of contamination of thelandfill cover and the horizontal extent of surface contamination.The sample results provided information to help characterizelandfill waste materials and identify surficial migration ofcontaminants from the landfill. These data also providedinformation necessary to assess the risk posed to persons andanimals onsite and in the surrounding areas.

In order to obtain the necessary data, samples were collected fromfour general locations as follows:

o Cover Material - locations on the landfill soil coverthat was placed over the waste.

o Areas of Erosion - locations on the landfill where thecover material has been partially or fully eroded. Atsome locations waste material was visible at the surface.

o Surrounding the Landfill - locations at the perimeter ofthe landfill.

o Background - locations that appeared to be undisturbedby landfilling activities based on historical data andobservations while onsite.

3.2 METHODOLOGY

Soil samples were collected on December 19 and 20, 1988. Asspecified in the Sampling and Analysis Plan, all samples were tobe collected for full TCL organics and TAL organics analyses by theContract Laboratory Program (CLP). Samples were to be collectedusing stainless steel spoons or scoops. However, due to the frozenground at most locations, the spoons would not penetrate the soil.

The alternate method selected involved chiselling the soil from theground surface using decontaminated steel chisels and a hammer.Samples were collected from approximately 0 to 2 inches below theground surface. Once loosened, the soil was transferred todecontaminated stainless steel bowls using decontaminated stainlesssteel spoons. Soil in the bowl was chopped into small pieces andmixed before being transferred to the sample containers. Thevolatile organic analysis component of each sample was notcollected because of the extreme agitation of the soil duringsampling collection and the inability to adequately pack the soilinto the volatile organic sample containers. Samples for volatileorganic analysis will be collected from the same locations at afuture date when the ground is not frozen.

3-1

Soil samples were collected from 36 locations as shown on Figures3-1 and 3-2. Figure 3-1 indicates sampling locations in thelandfill area. Figure 3-2 presents background surface soillocations. The sample locations are grouped by category (covermaterial, areas of erosion, areas surrounding the landfill,background) in Table 3-1. In addition, brief descriptions of thelocations and samples are provided.

3-2

S C A L EO 2OO

REM V

LANDFILL SOIL SAMPLE LOCATIONSHUNTS DISPOSAL LANDFILL SITE

CALEDONIA, Wl

D A T E

APRIL 1989

C.C.JOHNSON & M A L H O T R A . P . C . 3-3

S C A L E0 300

D A T EAPRIL 1989

REM V

BACKGROUND SOIL SAMPLE LOCATIONSHUNTS DISPOSAL LANDFILL SITE

CALEDONIA, Wl

FIGURE

3-2

C.C.JOHNSON & MALHOTRA.P .C . 3-4

TABLE 3-1

SOIL SAMPLE DESCRIPTIONSHUNTS DISPOSAL LANDFILL SITE

CALEDONIA, WI

SAMPLE NUMBER

COVER MATERIAL

SL-9SL-10SL-16SL-17SL-23SL-24SL-36

AREAS OF EROSION

SL-2SL-3SL-5SL-7SL-8SL-11SL-15SL-19SL-20SL-22SL-25SL-2 8

LOCATION DESCRIPTION

GrassyPoorly vegetatedPoorly vegetatedBarrenPoorly vegetatedGrassyModerately vegetated

BarrenBarrenBarrenBarrenBarrenBarrenBarrenPoorly vegetatedBarrenBarrenPoorly vegetatedBarren

SURROUNDING THE LANDFILL

SL-1SL-4SL-6SL-12SL-13SL-14SL-18SL-21SL-26SL-27SL-29SL-30

GrassyGrassyGrassyGrassyGrassyGrassy/woodedPoorly vegetated/woodedPoorly vegetated/woodedGrassyGrassyGrassyGrassy

SOIL DESCRIPTION

SiltSilty fine to medium sandSilty medium sandFine to medium sandSilty fine sandSilty fine sandFine to medium sand

Clayey siltFine sandFine to medium sandSilty fine sandFine to medium sandSilty fine sandFine sandClayey, fine sandy siltSilty fine sandClayey, silty fine sandSilty claySilty clay

Silt and fine sandClayey siltSiltFine sandy siltClayey siltClayey siltClayey siltClayey siltSiltSilty clayClaySilty clay

BACKGROUND

SL-31SL-32SL-33SL-34SL-35

GrassyBarren/woodedGrassy/woodedGrassy/woodedPoorly vegetated/wooded

SiltSiltSilty, clayey medium sandClayey siltClayey silt

3-5

4.0 SURFACE WATER AND SEDIMENT INVESTIGATION

4.1 PURPOSE AND SCOPE

The surface water and sediment investigation was conducted todetermine the nature and extent of contaminant migration from thelandfill into these media. Samples were collected from the RootRiver, the onsite lake, marshes, intermittent streams in thevicinity of the landfill, and background locations. Theselocations were selected to identify potential migration ofcontaminants from the landfill via surface water runoff, erosionand shallow groundwater discharge. All samples were collected forTCL organic and TAL metals analyses by the CLP.

Surface water and sediment samples were collected from 20 locationsduring December 6-13, 1988. Two locations in the middle of theonsite lake were not collected because the lake was frozen. Asecond round of surface water samples will be collected at a futuredate. Samples from the middle of the lake will be collected duringthe second round of sampling.

4.2 METHODOLOGY

Twenty-five surface water samples were collected from 20 locationsduring the investigation. Surface water sample locations are shownon Figure 4-1. At each of the five locations on the Root River(SW-15 through SW-19) two samples were collected. One sample wascollected at the surface near the landfill side shore. The othersample was collected near the bottom of the river in the center ofthe channel. Table 4-1 provides a description of each surfacewater sampling location. Surface and subsurface samples collectedfrom the Root River were designated with the letters A and B, re-spectively.

At most locations, samples were collected by allowing the surfacewater to flow directly into the sample containers. At fourlocations where the surface water was shallow (SW-9 through SW-12)a dedicated 8 02. glass intermediate sample bottle was used tocollect the sample. Water was decanted from the intermediatebottle into the inorganic and semivolatile organic analysis samplecontainers. Volatile organic analysis sample containers werefilled directly from the surface water. At eight locations ice wasremoved from the surface prior to sample collection (SW-4,7,15through 20).

The five subsurface river samples were collected by wading to thedesired sampling location. A clean 80 oz. amber glass intermediatesample bottle was immersed upstream of the sampler to a depth 6 to12 inches from the river bottom and allowed to fill. Inorganic andvolatile organic analysis sample containers were filled using theintermediate bottle. Semivolatile organic analysis sample bottleswere filled directly. Subsurface samples were originally intended

4-1

SW-14COUNTY LINE RO

SURFACE WATERSAMPLE LOCATION

S C A L E500'O'

D A T E

APRIL 1989

REM V

SURFACE WATER SAMPLE LOCATIONSHUNTS DISPOSAL LANDFILL SITE

CALEDONIA, Wl

FIGURE

4-1

C.C.JOHNSON & M^ L H O T R A . P . C .

TABLE 4-1

SURFACE WATER AND SEDIMENT SAMPLE DESCRIPTIONSHUNTS DISPOSAL LANDFILL SITE

CALEDONIA, WI

SAMPLENUMBER

123456769101112131415A15B16A16B17A17BISA18B19A19B20

SURFACE WATERLOCATION

Flowing streamGravel pit lakeOnsite lakeMarshOnsite lakeOnsite lakeOnsite lakeStagnant streamStagnant streamMarshMarshMarshMarshFlowing streamRoot River - shoreRoot River - centerRoot River - shoreRoot River - centerRoot River - shoreRoot River - centerRoot River - shoreRoot River - centerRoot River - shoreRoot River - centerGravel pit lake

SEDIMENTDESCRIPTION

Fine sand and siltSilty, gravelly sandFine to medium sandSilt and clayGravelly, medium sandGravelly, fine sandSandy claySilt and claySiltClayey siltClayey siltSiltSilt and claySiltSiltNo sample collectedSilty, gravelly sandNo sample collectedSilty, gravelly sandNo sample collectedClayey siltNo sample collectedSilt and clayNo sample collectedSilty, gravelly sand

4-3

to be collected and conveyed to the surface using a stainless steelKemmerer sampler. However due to the shallow depth of the river(2-3 feet), direct immersion of the bottles was consideredappropriate. One sample (SW-19B) was collected using the Kemmerersampler.

For each surface water sample, an additional container was filledfor the determination of temperature, pH, conductivity, dissolvedoxygen and hardness. These parameters were determined using fieldinstruments and analyses. Field measurements for each sample areprovided in Appendix . All of the measurements were within theexpected ranges for surface water samples.

Twenty sediment samples were collected from the same locations asthe surface water samples. Sediment samples were collected afterthe surface water samples were collected to prevent the inclusionof entrained sediment in the surface water samples. Samples fromthe Root River were only collected near the bank where sedimentaccumulation occurred. Sediment sample locations are shown onFigure 4-2. Descriptions of the sampling location and the sedimentare provided for each sample in Table 4-1.

Sediment was collected from the top four inches at each locationusing long-handled, decontaminated stainless steel spoons.Sediment was scooped with a spoon and placed into a decontaminatedstainless steel bowl until the bowl was full. Gravel and plantmaterial was removed from the collected sediment prior to fillingthe sample containers. The volatile organic analysis container wasfilled first using a stainless steel spoon. The remainder of thesediment in the bowl was thoroughly mixed prior to beingtransferred to the inorganic and semivolatile organic analysissample containers.

4-4

SD-14COUNTY LINE RO

GRAVELPIT 1 L J '

SEVEN MILE RD.

SEDIMENT SAMPLE LOCATION

REM V

SEDIMENT SAMPLE LOCATIONSHUNTS DISPOSAL LANDFILL SITE

CALEDONIA,

D A T EAPRIL 1989

C.C.JOHNSON & M A L H O T R A . P . C .4-5

5.0 GEOLOGIC INVESTIGATION

5.1 PURPOSE AND SCOPE

Soil borings were made at the Hunts Disposal Landfill Site toevaluate local geologic conditions, to obtain samples of subsurfacesoil for chemical and physical laboratory analysis and to installgroundwater monitor wells. This section describes the geologicinvestigation associated with the borings. This section includesa description of the drilling methodogy and the geologicinterpretation of the upper sediments. Section 6 describes themethods, and results of chemical analysis of the split-spoonsamples taken during the geologic investigation. The monitor wellsare discussed in Section 7.0.

Soil borings were completed at 12 locations at the periphery of thelandfill and on adjoining properties. Eight of these locationsconsisted of clustered shallow and deep borings and four locationshad single, shallow borings. Deep soil borings were drilled intothe top of the silt/clay till to characterize the till and allowinstallation of deep monitor wells at the top of this layer(screened in the overlying sand and gravel). The shallow boreholeswere drilled to allow installation of shallow monitor wells thatstraddle the water table. Deep boreholes were drilled 25 to 50feet deep and shallow borings were 15 to 20 feet deep.

Three additional borings were completed on the surface of thelandfill. These were conducted to characterize the waste materialand the underlying natural lithology, to determine the thicknessof the waste, and to allow installation of landfill monitor wells.Borings into the landfill ranged 34 to 48 feet deep. The locationof the soil borings and corresponding monitor wells are shown onFigure 5-1.

5.2 METHODOLOGY

Drilling was performed by Exploration Technology, Inc. (ETI) ofMadison, Wisconsin using a Diedrich D-50 track-mounted drill rig.A Rem V hydrogeologist was present throughout the work to directETI personnel and monitor all drilling activities. The hollow stemauger method was used for all soil borings except SB-10 asexplained below. Borings approximately 10 inches in diameter wereproduced with the 6 1/4-inch I.D., 9 5/8-inch O.D. augers. Siteconditions necessitated the use of a screened lead auger on allholes except the initial exploratory boring (SB-11D). The use ofa screened lead auger was necessary because the saturated,unconsolidated units at the site freguently heaved during formationsampling and well installation operations. In addition to thescreened lead auger, the "drive and wash" method of drilling wastried, for soil boring SB-10, in order to mitigate the heaving sandproblems.

5-1

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' LANDFILLSB-5S,D

\ SB-I4S \

*\ ' I ». -^-^-^'

S C A L E0 3OO

REM V

SOIL BORING LOCATIONSHUNTS DISPOSAL LANDFILL SITE

CALEDONIA, WlD A T E

APRIL 1989

C.C.JOHNSON & M A L H O T R A . P . C .

The "drive and wash" technique employed to drill soil boring SB-10utilized 6-inch I.D. steel casing and a 5 7/8-inch diameter triconebit. The lead casing was equipped with a hardened steel chamfereddrive shoe to facilitate penetration of the unconsolidatedsediments. Plumbness of the boring was assured by drilling theuppermost 5 feet with a 6 1/4-inch I.D. auger flight. The boringwas advanced by impact-driving the casing 2 to 3 feet with a 300-pound, centered weight allowed to free-fall a distance ofapproximately 36 inches. Formation within the driven casing wasthen "flushed" out by water-rotary drilling inside the casing withthe tricone bit. This alternating sequence of driving and drillingwas repeated until sampling depths and the total depth wereachieved. Although the "drive and wash" method was effective inpreventing heave, the Moyno 3L6 pump used to clear the casing offormation material was not able to remove the coarser fractions(very coarse sands to very coarse gravel), thus requiringoverdrilling to achieve total depth. Relative to hollow stem augerdrilling this method was slower. Hence, the "drive and wash"technique was utilized only to drill soil boring SB-10. All theremaining holes were bored using augers.

Auger-drilled boreholes were advanced by drilling with a pilotbit/center plug assembly at the head of the auger string. Theassembly consisted of a four-bit pilot bit with a tracking 18-inchreverse-spiral center plug. The assembly was removed to allowsplit-spoon sampling. After each sample was collected drilling wascontinued with the pilot bit/center plug assembly in place. Augerflights were added in 5-foot lengths until the target depth of eachboring was achieved. When necessary, water-rotary drilling witha 5 7/8-inch diameter tricone bit was employed to clear heavedformation from within the auger string. A static column of wateralso was maintained in the auger string at most borehole locationsto prevent shallow sediments from entering the auger string.Although each of the measures described above was individually orcollectively effective in minimizing formation heave, overdrillingto attain the amount of open borehole necessary for subsequent wellinstallation also was required at several locations. Prior to wellinstallation, the total depth of the borehole was verified bysounding the bottom of the boring with a weighted water-levelprobe.

Sampling of borehole sediments was performed using a 3-inchdiameter split-spoon. Two-foot long split-spoons were driven withthe aid of a rig-mounted "cathead" using a 140-pound centeredweight. The weight was allowed to free-fall a distance of 30inches until the sample barrel had moved 24 inches or refusaloccurred. One hundred impacts of the weight over an interval of6 inches was established as the refusal specification.Additionally, four Shelby tube samples were taken from differentboreholes. Each tube was pushed into the formation using the drillspindle and the rig's hydraulic system. The tube samplers wereleft in place a minimum of 15 minutes, twisted with a pipe wrenchtwo complete turns, removed, and sealed with hot wax and plastic

5-3

end caps. Pour additional geotechnical samples were collected fromsplit-spoon samplers at 4 locations and placed in 8-ounce glassjars.

An initial exploratory boring (SB-11D) was continuously split-spoonsampled from the ground surface to a total depth of 45 feet,approximately 20 feet into the silt/clay till. At each subsequentwell cluster and single well location, split spoon samples werecollected from the ground surface to the depth of the water table.Additional sampling was performed on 5-foot centers or whenever thedrilling penetration rate changed noticeably. Continuous split-spoon samples were collected at the bottom six to ten feet of thedeep boreholes to characterize the silt/clay layer.

The number of impacts required to drive the split-spoon apparatuseach 6-inch interval was recorded in a field drilling log.Recovery was recorded and determined by carefully opening eachsample and discarding any disturbed material. A detailedlithologic description of each split-spoon sample documenting thelithotype, Munsell color, sorting, consolidation, moisture content,and distinguishing characteristics was also recorded in the fieldlog and is presented in Appendix .

Drill rods and the screened lead auger were decontaminated with asteam cleaner prior to drilling each boring. The drill rig, alldownhole drilling and sampling equipment, and all drilling supportequipment were steam-cleaned prior to drilling at each newlocation. Decontamination of the split-spoon samplers and samplingutensils between sampling events was performed using an initialsoap (Liquinox) and water wash, a fresh water rinse, a rinse withpesticide grade isopropyl alcohol, and a final rinse with HPLClaboratory grade water.

Health and safety measures employed during the drilling programincluded the use of Level D personal protection by all personnelin the work area. Continuous monitoring of the work area fororganic and explosive vapors was performed with an HNuphotoionization detector with an 11.7 eV probe and combustible gasindicator, respectively. Soil borings located on the landfill weredrilled following Level C health and safety guidelines.

5-4

6.0 SUBSURFACE SOIL SAMPLING

6.1 PURPOSE AND SCOPE

Subsurface soil samples were obtained from 12 soil boring locationsat the perimeter of the landfill. In addition to determininglithologic information, selected samples were collected for TCLorganic and TAL metals analyses by CLP laboratories. Results ofthese analyses were used to document the presence of subsurfacesoil contamination and to determine the extent of contaminantmigration.

6.2 METHODOLOGY

All split-spoon samples were screened for volatile organiccompounds to determine which samples would be sent to the laborato-ry for chemical analysis and to determine how to dispose of thedrill cuttings. Immediately after the split-spoon was opened, theair above the sample was monitored using an HNu photoionizationdetector with an 11.7 eV probe. All positive deflections wererecorded in the field logbook. In addition, a headspace sample wascollected by half filling a 40 ml glass vial with the sample andcovering the top with aluminum foil. These vials were transportedto the trailer and allowed to warm to room temperature (approxi-mately 70°F). Then the aluminum foil was punctured with the tip ofthe HNu probe so that the volatile organic compounds in theheadspace could be measured. The results of the headspace analysesdid not indicate significant volatile organic contamination in anyof the samples and therefore was not useful for determining whichsamples to send for analysis.

Split-spoon samples were selected for analysis based on visualobservations, HNu readings when the split-spoons were opened, anddepth. Approximately three samples from each boring location weresent to CLP laboratories for analysis. These samples werecollected near the water table surface, at the base of the sandand gravel (just above the till) and at a depth approximatelymidway between the water table and the till layer. Soil boringlocations shown on Figure 6-1.

Subsurface soil samples were collected using three-inch diametersplit-spoons as described in Section 5.1. Split-spoons weredecontaminated prior to sample collection. Decontaminationprocedures included a soapy water wash, potable water rinse,pesticide grade isopropyl alcohol rinse and a final rinse with HPLCgrade water.

Once retrieved, the split-spoon was opened in a manner thanminimized disturbance of the sample. The portion of the sample forheadspace and CLP volatile organics analyses was immediatelytransferred to the appropriate sample containers using a decon-taminated stainless steel spoon. The remainder of the sample was

6-1

«M?

fv-Vi ('1^0

__

^

REM V

SOIL BORING LOCATIONSHUNTS DISPOSAL LANDFILL SITE

CALEDONIA, WlD A T E

APRIL 1989

C.C.JOHNSON & M A L H O T R A . P . C .

transferred to a decontaminated stainless steel bowl and thoroughlymixed prior to being placed into the semivolatile organic andinorganic analysis sample containers.

6-3

7.0 MONITOR WELL INSTALLATION AND GROUNDWATER SAMPLING

7.1 PURPOSE AND SCOPE

Twenty-two monitor wells were installed at the Hunts DisposalLandfill Site to determine the type and extent of contamination inthe water table aquifer at the site. The wells were installed inboreholes drilled during the geologic investigation (Figure 7-1).Details of the geologic investigation are presented in Section 5.

Nineteen wells were installed at twelve locations at the perimeterof the landfill and the surrounding area. Seven locations containa cluster of two wells. Clusters consist of a shallow wellscreened at the water table surface and a deep well screened at thebase of the water table aquifer (immediately above the till). Fivelocations contain single shallow wells that are screened at thewater table surface. Shallow wells were installed to monitorgroundwater quality at the surface of the water table aquifer andare designed to identify potential contaminants that have a lowerdensity than water. The deep wells were screened at the base ofthe sand and gravel to monitor for contaminants that are denserthan water and may accumulate above the low permeability till.

Three additional shallow wells were installed into the landfill andscreened to intersect the water table surface in the waste. Table7-1 presents a summary of monitor well depths, elevations andscreened intervals.

7.2 METHODOLOGY

7.2.1 WELL INSTALLATION

The wells installed at the periphery of the landfill wereconstructed of 2-inch I.D. Schedule 80 polyvinyl chloride (PVC)screen and casing. The three monitor wells installed into thelandfill were constructed of 2-inch I.D. Type 304 stainless steel.

Screens for the shallow and landfill wells were 10 feet in length.The screen length of the deep wells was 5 feet. Well screens forall applications were continuous wrapped with 0.010-inch slots.Wells installed in the landfill were constructed of Channel Packscreen manufactured by Johnson Screens. Channel Pack screensconsist of an outer screen and an inner screen with the annulusbetween the screens filled with 40-60 silica sand. Two-foot silttraps were attached to the bottom of the screen on all monitorwells installed after the completion of the first two well clusters(Nos. 11 and 12), due to the large percentage of fines observed inthe split-spoon samples from the screened intervals.

7-1

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O, 0 ) LANDFILL

'Ito MW-5S, D

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MW-IIS, D ;7̂ _̂li. «MW-4S

S C A L E0 300

REM V

MONITOR WELL LOCATIONSD A T E

APRIL 1989HUNTS DISPOSAL LANDFILL SITE

CALEDONIA, Wl

C.C.JOHNSON & M A L H O T R A . P . C . 7-2

7-1NOMUOft HELL SUHHARr

HUHI5 DISPOSAL LANDFILL SUECALEDONIA. WISCONSIN

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t Instilled bv the City of Oik Creek, construction detail* unknownElevat ions Mill be included after concrete cadi are set and well! are surveyedAll depths in feet beloit pround surface

7-3

Where the total depth of the boring was three or more feet belowthe bottom of the well screen, the borehole was backfilled toapproximately one foot below the well screen with bentonite pelletsor a bentonite slurry. Pellets were introduced using the free-fallmethod. Quick-Gel slurry was tremie-piped to the desired depth indeeper borings rather than using pellets, which hydrated guicklyand bridged when used in early installations.

The shallow and deep monitor wells at the periphery of the landfillwere installed using the 6 1/4-inch I.D. hollow stem augersemployed to drill the boreholes as temporary casing. Constructiondetails of a typical well cluster are shown on Figure 7-2. Afilter pack of #30 silica sand was placed in the annular spacesurrounding the silt trap, screen and the lowermost two feet of theriser pipe. A buffer of very fine grained silica sand 6 to 12inches thick was placed above the #30 sand to prevent grout orpellets from entering the filter pack. Filter pack and buffer sandwere emplaced by free-fall in 2- to 3-foot lifts. The auger stringwas then lifted 1 to 2 feet, allowing the sand to flow out and fillthe annular space. Use of this technique and maintaining a statichead of water at the top of the auger string during installationhelped to minimize formation heaving.

A 2- to 3-foot thick bentonite pellet seal was placed above theannular sand by the free-fall method and allowed to swell for aminimum of eight hours. One deep well (MW-6D) required tremieplacement of a bentonite slurry for the seal due to pelletbridging. After the bentonite had swelled, the annulus was groutedwith a bentonite cement slurry. Approximately 6 to 8 gallons ofwater and 5 pounds of powdered bentonite were mixed with each 94-pound bag of Type III Portland cement to form the grout. Grout waspoured directly into the borehole annulus where the bentonite sealwas less than 5 feet below ground surface. All other wells weretremie-grouted with the auger string in place as temporary casing.Wellhead security is provided by locking 6-inch diameter steelprotective casings which are enclosed in the grout. Concrete padswere not installed around the wells following installation due tothe low temperatures. The pads will be poured at a future date.

Wells screened at the water table were placed with approximately10 to 30 percent of the screen above the static water level toaccommodate seasonal water level fluctuations. Where the top ofthe 10-foot screen was within 5 feet of the ground surface or whereclayey sediments would be screened if the planned 33 percentabove/67 percent below screening ratio were used, a smallerpercentage of the screen was placed above the water tuble. Annularsand above the screen and bentonite pellet thicknesses in thesewells were also reduced.

Wells installed into the landfill were constructed in a mannersimilar to the perimeter wells. However, wells in the landfill

7-4

SHALLOWWELL

TSi

LEGEND

CONCRETE PAD

8ENTONITE CEMENTGROUT

8ENTONITE PELLETS

VERY FINE SAND

COARSE SAND

VENTED CAP (TYP.)

STEEL CASING (TYP)

PVC CASING (TYP)

•2 0 PVC SCREEN(10-FOOT)

2" 0 PVC SILT TRAP (TYR)

2"0 PVC SCREEN(5-FOOT)

DEEPWELL

GROUND SURFACE

WATER TABLE

SAND AND GRAVEL

SILT AND CLAY

S C A L ENO SCALE

D A T E

APRIL 1989

REM V

TYPICAL WELL CLUSTERHUNTS DISPOSAL LANDFILL SITE

CALEDONIA, Wl

FIGURE

7-2

C.C.JOHNSON & M A L H O T R A . P . C . 7-5

were sealed from the top of the bentonite pellets to the groundsurface with a high solids bentonite grout (Volclay). Volclay wasutilized to reduce grout loss into the waste because it is thickerand cures faster than bentonite cement grout. Construction detailsfor a typical landfill well are shown on Figure 7-3.

7.2.2 WELL DEVELOPMENT

Monitor wells at the perimeter of the landfill were developed afterthe grout had set for a minimum of 48 hours. The wells weredeveloped by pumping and surging with compressed air.Decontaminated hose was set in the well to a point approximately6 inches from the bottom of the screen and connected to a trailermounted compressor. A filter was placed on the air line to removeimpurities. Air forced through the hose lifted water and sedimentup the well casing to a discharge hose at the top of the well.Wells were developed for a minimum of two hours and until dischargewater was clear and free of visible sediment and when temperature,conductivity and pH measurements stabilized. Because many of thewells were screened in fine grained materials, the discharge fromsome wells remained cloudy. These wells developed for a minimumof three hours and until readings stabilized and clarity showed noimprovement.

Six of the wells did not yield enough water to be adeguatelydeveloped using compressed air alone. These wells were MW-6D, US,11D, 12S, 14S and 15S. Each of these wells was developed byagitating with a surge block or bailer and pumping with aperistaltic pump. The wells were alternately pumped dry andallowed to recover and then pumped at a constant low flow rateuntil the discharge cleared and temperature, pH and conductivityreadings stabilized.

After discussion with EPA, it was decided that monitor wellsinstalled into the landfill would not be developed. This decisionwas made because the wells were screened in waste rather thannatural soils and because the Channel Pack screen provides a gradedfilter pack. These wells were bailed before purging and samplingto remove any sediment that may have entered the screens duringinstallation.

7.2.3 GROUNDWATER SAMPLING

All of the wells installed by REM V and two of the three existingwells installed by the City of Oak Creek were sampled betweenFebruary 27, 1989 and March 2, 1989. The Oak Creek well that wasinstalled into the landfill (MW-3) contained little water andtherefore, could not be sampled. All wells were sampled for fullTCL organic compounds, TAL metals, and total dissolved solids (TDS)analyses by CLP laboratories. Organic samples were analyzed underspecial analytical service protocol for low detection limits.

7-6

VENTED CAP-

'^ STEEL CASING

CONCRETE PA

VOLCLAY GROUT

2"0 STAINLESS STEEL CASING-

BENTONITE PELLETS

VERY FINE SAND

2"0 STAINLESS STEELCHANNEL PACK SCREEN'

(IO —FOOT)

COARSE SANO-

2" 0 STAINLESS STEEL SILT TRAP-

BENTONITE SEAL

GROUND SURFACE

SAND COVER

WASTE

WATER TABLE

NATURAL FORMATION

S C A L ENO SCALE

D A T E

APRIL 1989

REM V

TYPICAL LANDFILL MONITOR WELLHUNTS DISPOSAL LANDFILL SITE

CALEDONIA , Wl

FIGURE

7~3

C.C.JOHNSON & M A L H O T R A . P . C .7-7

Samples for metals and TDS analyses were passed through a 45-micronfilter prior to being shipped to the laboratories. Metals analysissamples were preserved following filtration.

Prior to sampling, all wells were purged using decontaminatedstainless steel or teflon bailers and dedicated lengths ofpolypropylene cord. Wells were purged until a minimum of threewell volumes were removed if conductivity, pH and temperaturemeasurements of the purged water stabilized. If measurements didnot stabilize, purging continued until a minimum of five wellvolumes were evacuated. Monitoring wells MW-llS, 11D, 15S, LW-1and LW-3 were purged until they were bailed dry. Finalconductivity, pH and temperature measurements of the purged waterare contained in Appendix .

Monitor wells were sampled immediately following purging. Wellsthat were purged dry were allowed to recover for approximately onehour before sampling. Groundwater samples were collected usingdecontaminated stainless steel or teflon bailers with dedicatedlengths of polypropylene bailer cord. Samples were collected fromthe top of the water column in the well in a manner that preventedthe bailer cord from contacting the water in the well. Followingremoval from the well, bailers were emptied directly into theappropriate sample containers, with the volatile organic vialsbeing filled first.

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9.0 RESIDENTIAL WELL INVESTIGATION

9.1 PURPOSE AND SCOPE

A residential well survey was conducted to determine where selectedresidences in the Hunts Disposal Landfill Site area obtain theirdrinking water. These data identified potential receptors ofgroundwater from the site. Selected residential wells were thensampled to determine if a public health risk exists from landfillcontaminants.

9.2 METHODOLOGY

The residential well survey and sampling was conducted on November15 and 16, 1988. In order to identify, any potential risk toresidents as quickly as possible, this was the first field taskperformed.

A door to door survey was conducted on selected homes near thelandfill. The survey concentrated on homes in the immediate areaof the site, particularly those downgradient. Each resident wasasked a list of questions concerning their well including:

o Use of watero Well depth and diametero Date of well constructiono Well drilling contractoro Type of well and riser pipe materialo Volume of holding tanko Type of treatment systemo Water quantity or quality problems

These data were recorded in the field logbooks. As a result of thesurvey, 14 residences were selected for sampling. The locationsof the residences selected are shown on Figure 9-1.

Prior to sampling, the residential wells were purged to ensure thatfresh groundwater was collected. Seven of the 14 residencessampled had an on-line treatment system. All samples werecollected before passing through the treatment system. At 12 ofthe 14 locations the samples were collected from a tap before theholding tank. At the two locations where samples were collectedafter passing through the holding tank, the well volume purgedexceeded the holding tank volume. All wells were purged for aminimum of 20 minutes prior to sampling. Sample bottles werefilled directly from the tap. All samples were collected for a fullTCL organics and TAL metals analysis by the EPA Region V CentralRegional Laboratory. Special low detection limit analysis wereperformed. Temperature, pH and conductivity measurements weretaken at each location immediately prior to sampling. These dataare presented in Appendix .

9-1

RESIDENTIAL WELLLOCATION AND DEPTH

RW- 3, 127RW-14, 182*RW-12, 196'

S C A L EI POO

D A T EA P R I L 1989

REM V

RESIDENTIAL WELL SAMPLE LOCATIONSHUNTS DISPOSAL LANDFILL SITE

CALEDONIA, Wl

F IGURE

9-1

C.C.JOHNSON & MALHOTRA.P.C.