PB96964102
PB96-964102
EPA/ROD/R05-96/296
June 1996
EPA Superfund
Record of Decision;
Ripon City Landfill,
Ripon, WI
3/27/1996
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 5
77 WEST JACKSON BOULEVARD
CHICAGO, IL 60604-3590
REPLY TO THE ATTENTION OF:
R-19J
George E. Meyer
Secretary
Wisconsin Department of Natural Resources
101 South Webster
P.O.Box 7921
Madison, WI 53707
Dear Mr. Meyer:
The Uniced States Environmental Protection Agency (U.S. EPA)
hereby concurs with the remedy identified in the enclosed Record
of Decision (ROD) completed by the Wisconsin Department of
Natural Resources (WDNR) for the Ripon Landfill Site. Our
concurrence is in accordance with 40 CFR 300. 5 15 (e) (2) (i) and
(ii) and is based upon our review of the documents contained on
the first enclosure to this letter. We were briefed on the ROD
by a WDNR representative.
We look forward to our continuing involvement on the Ripon
Landfill Site.
Sincerely yours,
Valdas V. Adamkus
Regional Administrator
Enclosures
Recycled/Recyclable • Printed with Vegetable Oil Based Inks on 100% Recyded Paper (40% Postconsumer)
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-2-
Documents reviewed for the Ripor. Landfill Site
1) Record of Decision
2) Responsiveness Summary
3) Remedial Investigation Report
4) Feasibility Study
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RRCORP OF DECISION
REMEDIAL ACTION FOR THfc SSOUkCS CONYSOL AND GROUNDWATER OPERABLE UNITS
RIPON FF/NN LANDFILL, RIPON, WI
Site Name and Location
The Ripon FF/NN landfill Superfund site is located at the intersection of
Highways FF and NN in the Town of Ripon, Fond du Lac County, Wisconsin. It is
approximately two miles northwest of the City of Ripon, WI. The site is
located in the SE \A of the SE '4 of Section 7, T16N, R14E.
Statement and Basis of Purpose
This decision document represents the selected source control and groundwater
remedial action for the Ripon FF/NN landfill, developed in accordance with
CERCLA, as amended by SARA, and to the extent practicable, the National
Contingency Plan. The attached summary of remedial alternatives identifies
the information contained in the administrative record for this site upon
which the selection of the remedial action is based.
Assessment of the Site
Actual or threatened releases of hazardous substances from the site, if not
addressed by implementing the remedial action selected in this Record of
Decision (ROD), may present an imminent and substantial danger to public
health, welfare or the environment.
Description of the Selected Remedial Actions
The Department of Natural Resources has evaluated remedial alternatives for
two operable units at the site: a source control operable unit and a
groundwater operable unit. The selected source control remedy is Alternative
O, Composite Landfill Cap and Passive Gas Venting in conjunction with a
groundwater monitoring plan. Details of the selected source control operable
unit remedy can be found in the Feasibility Study. The specific components of
the source control operable unit remedy include:
* constructing a composite landfill cover (i.e. a landfill cap made with
both a plastic membrane and soil materials) over the entire landfill
* installing a passive landfill gas venting system as part of the
composite cap to effectively vent landfill gas from the waste
* monitoring of the groundwater quality to determine the effectiveness of
the landfill cap towards improving groundwater quality
* monitoring the landfill gas probes around the landfill to make sure that
landfill gas is not migrating away from the site in an uncontrolled
manner.
* maintenance of the landfill cap to repair erosion that may develop
* ' a deed restriction prohibiting disturbing the landfill cap except for
maintenance purposes
* fencing of the landfill perimeter to restrict access
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For the groundwater operable unit, the Department has selected Alternative A,
the No Action alternative. The groundwater contamination that has migrated
from this landfill is not severe enough to warrant active groundwater remedial
measures to restore groundwater quality. The implementation of the source
control operable unit remedy will result in decreased migration of
contaminants from the landfill to the groundwater.
Statutory Determination
These remedies are protective of human health and the environment, comply with
Federal and State requirements that are legally applicable or relevant and
appropriate requirements (ARARs) for this action, and are cost effective.
These remedies utilize permanent solutions and alternative treatment to the
maximum extent practicable for this site. However, because treatment of the
principal threats of the site was not found to be practicable, these remedies
do not satisfy the statutory preference for treatment as a principal element.
Because these remedies will result in hazardous substances being left on site,
a review of the remedies will be conducted to ensure that the remedies
continue to provide adequate protection of human health and the environment.
That review of the remedies will take place within 5 years after the remedial
actions have been implemented.
George Mey^r, Secretary (] Date
Wisconsin Department of
Natural Resources
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SUMMARY OF REMEDIAL ALTERNATIVES SELECTION
RECORD OP DECISION (ROD)
RIPON FF/NN LANDFILL
Findings of Fact.
The following findings of fact summarizes the information contained in the
administrative record for the Ripon FF/NN landfill site. The selected source
control and groundwater remedial actions are based upon information contained
in the administrative record.
The-Wisconsin Department of Natural Resources (WDNR) finds that:
I. SITE NAME, LOCATION AND DESCRIPTION
The Ripon FF/NN landfill was listed on the National Priorities list (NPL) by
the U.S. Environmental Protection Agency (EPA) in May, 1994. The landfill is
located in western Fond du Lac County, about two miles northwest of the City
of Ripon, WI. More specifically, the site is located at the intersection of
Highways FF and NN in the SE V* of the SE '4 of Section 7, T16N, R14E. The
landfill is 7.3 acres in size and has a volume of approximately 180,000 cubic
yards of waste. The location is shown on Map 1.
Landfilling occurred between 1967 and 1983. Various entities operated the
site over the years, although the City of Ripon and the Town of Ripon were
responsible for operations during much of the life of .the landfill. The
property is owned by Mrs. Arline Sauer. The landfill accepted commercial,
industrial and residential waste, including approximately 3 million gallons of
municipal wastewater treatment plant sludge.
Between 1985 and 1992 the- site was used to grow hay. Since 1992 the land has
been planted in a grass cover. Agricultural crops are still grown on a
property just east of the site. The site is fenced, but vehicle access is
possible at two locations from CTH NN into the landfill. Across Highway NN to
the west of the site is a sand & gravel quarry.
II. SITE HISTORY AND ENFORCEMENT ACTIVITIES
In 1967, Speed Queen Corporation leased the property for disposal of
industrial wastes from it's facility in Ripon. In 1968, the City of Ripon
leased the property. In 1978, the City and the Town of Ripon were signatory
to the lease. A license to operate the landfill was issued by WDNR to the
City of Ripon in 1969. The site accepted wastes between 1967 and 1983. The
site was capped in 1985 with a clay cap. Vegetation was established to
minimize erosion. A gas venting system (trench with gooseneck vents) was
placed in a north-south orientation along the western edge of the landfill.
A private residence is located approximately 350 feet south of the landfill.
The water supply well to this home was monitored for VOCs in 1984 and a couple
of VOCs were detected, including vinyl chloride. Subsequent sampling of the
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Ripon FF/NN
Landfill
HWY23
North
Ripon
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well by WDNR confirmed the presence of vinyl chloride. A replacement well was
drilled for this household. Sampling of the replacement well also confirmed
the presence of vinyl chloride. This well was abandoned in 1990. No water
supply well exists on the property and nobody is currently living in the home.
In the early 1980's the WDNR began evaluating municipal landfills for possible
inclusion on the "federal National Priorities List (NPL). A hazard assessment
was completed by WDNR utilizing the EPA Hazard Ranking System. The site
scored 51.9 and was recommended by WDNR to EPA for inclusion on the NPL. The
site was listed on the NPL in May, 1994.
In response to the WDNR recommending the site to EPA for inclusion on the NPL,
several Potentially Responsible Parties (PRPs) formed a group to investigate
the degree and extent of the environmental problems related to the site. This
group of PRPs entered into a contract with WDNR on August 14, 1992 to complete
the following:
1. Conduct, a remedial investigation (RI) which will adequately characterize
the site.
2. Perform a feasibility study (FS) to identify and evaluate potential
remedial options for the site.
3. Prepare plans and specifications for a landfill cap, and landfill gas
extraction system, as determined necessary by WDNR. These plans and
specifications are considered a source control operable unit.
4. Implement the source control operable unit.
Since the contract was signed, the PRP group has completed the RI and FS.
Data contained in these documents, and others in the administrative record are
used as the basis for this ROD.
III. Community Participation
The WDNR has established the administrative record for the site at the Ripon
Public Library. Since the library is a centralized and easily accessible
facility, the information at the library acts both as the administrative
record and the information repository. All information related to the site is
housed there. The library is located at 120 Jefferson Street in the City of
Ripon.
In April, 1993 WDNR issued a fact sheet announcing the start of the RI. This
fact sheet provided background and historical information about the site, as
well as details about how the investigation into the environmental
contamination would proceed. The fact sheet was followed by a public meeting
held at the Ripon City Hall on April 20, 1993. Approximately 40 people
attended the meeting. During the meeting, staff from WDNR and the Wisconsin
Division of Health (DOH) presented a summary of the -RI and also answered
people's questions about how the site, or the investigation may affect them.
In June and July, 1993 WDNR and DOH interviewed 23 people who expressed
interest in the site. These persons ranged from local politicians and local
press, to residents who lived near the site. The persons interviewed
expressed a good working knowledge of the site and it's history. The primary
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.cern by almost all interviewed was groundwater quality. Everyone expressed
"arest in knowing how far the contamination had spread and whether the
.-atamination would affect any private wells.
Local media also played a role in disseminating information about the site.
Articles about the landfill and RI occurred in the Oshkosh Northwestern (local
newspaper) on July 13 4 14, 1993. Also in July, 1993 WDNR staff took part in
a call in radio show on Ripon radio station WCWC.
In May, 1994 WDNR released another fact sheet providing a summary of the RI up
to that point in time. Most of the monitoring wells had been placed and
results of sampling were available. This fact sheet generated about 5-6 calls
to the WDNR project manager from persons requesting additional information
about the site.
Also in May, 1994 WDNR. prepared a Community Relations plan for the site. This
plan provides background information about the .City of Ripon, the landfill and
other points of interest in western Fond du Lac County. The Community
Relations Plan also summarizes information gathered from interested residents
during the WDNR interviews held in June and July, 1993.
IV. Scope of the Remedy
This Record of Decision encompasses both source control and groundwater
operable units. A source control remedy is designed to control (stop or
reduce) the migration of contamination to the environment, including
groundwater. For landfills the choice of source control options is rather
limited. Essentially it involves placing a cover or cap over the landfill to
reduce the amount of precipitation that can enter the waste. By reducing or
eliminating precipitation from entering the waste, the potential for that
liquid to extract contaminants from waste 'in the landfill is minimized.
For this situation, a composite landfill cap is the most effective way to
minimize the amount of precipitation that can enter the waste. A composite
cap has both soil and plastic components to it. The plastic membrane
essentially eliminates the ability of precipitation to enter the waste. The
soil components provide a stable surface on which the plastic membrane is
applied, covers the membrane to protect it from damage, and provides a rooting
and growing layer for vegetation to become established on the cap.
Constructed within the composite cap will be a .gas venting system. As organic
wastes decompose, they form a gas which is predominantly methane and carbon
dioxide. The gas venting layer will allow this gas to escape from the
landfill without damaging the cap.
The groundwater contamination from the site is fairly localized. While there
are elevated concentrations of certain VOCs present in groundwater near the
site, concentrations diminish greatly with distance away from the site. Data
indicate that the wetland located southwest of the site is the discharge point
for much of the groundwater. At the point of discharge into the wetland, VOC
concentrations are so low as to not cause a problem to the biota of the
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wetland. To keep track of contaminant concentrations with time, a groundwater
monitoring plan will be developed. The goals of the plan are to:
* effectively monitor contaminant concentrations with time
* determine that contaminants from the landfill don'.t affect any of the
private residences located near the site.
V. Summary of Site Characteristics
A. Topography
The landfill is located in a glaciated area of south central Wisconsin. The
area near the site consists of poorly sorted ground and end moraine deposits.
Outwash deposits of sand and gravel are evident in the quarry located just
west of the site. The landscape slopes gently eastward. The landfill rises
to an approximate elevation of CTH NN on the west (872 ft MSL) and slopes
approximately 20 feet lower (850 ft MSL} on the east.
B. Geology/Hydrogeology
The geology of the site consists of approximately 180 feet of unconsolidated
glacial deposits, primarily sand with some silty and clayey lenses and gravel
overlying bedrock. The bedrock is a Cambrian sandstone unit which is
approximately 150 feet thick near the site. The glacial unconsolidated
deposits and the Cambrian sandstone are the two principal aquifers in this
area. The municipal wells and many private wells use the sandstone as their
water source. The lower limit of the Cambrian sandstone aquifer is delineated
by the granite of the Precambrian at approximately 330 foot depth.
Depth to groundwater is variable and dependent upon topography. Groundwater
is present at depths ranging from approximately 5 to 50 feet below ground
surface with the water table occurring between 820 and 830 feet MSL. Shallow
groundwater at or near the water table flows to the southwest towards a
wetland. This flow system has an average horizontal gradient of approximately
0.01 ft/ft. Shallow piezometers screened between 30 and 40 feet below the
water table were used to confirm a southwesterly flow direction in deeper
unconsolidated deposits. The mean hydraulic gradient of the shallow
potentiometric surface is approximately 0.005 ft/ft. Groundwater flow within
the sandstone is believed to be westerly based on regional information.
C. Groundwater Contamination
A total of eight VOCs were detected in groundwater monitoring wells. Vinyl
chloride, cis 1,2-DCE, benzene, TCE and PCE were present at concentrations
exceeding NR 140 preventive action limits (PALs). Two of these compounds,
vinyl chloride and cis 1,2-DCE exceeded NR 140, Wis. Adm. Code enforcement
standards (ES). Three VOCs, vinyl chloride, cis 1,2-DCE and TCE, were
detected in samples from more than one location.
Two metals, iron and manganese, were detected in samples at concentrations
which exceed NR 140 ESs. Arsenic and cadmium were detected at concentrations
exceeding NR 140 PALs. These metal concentrations are likely due to the
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natural geology of the glacial deposits and the landfill doesn't appear to be
contributing significant quantities of metals to the groundwater.
Following the groundwater flow paths, contaminated groundwater exists from
under the landfill and extends to the south, and southwest of the landfill.
The discharge point for this contaminated groundwater is the wetland located
southwest of the site. The highest concentrations of VOCs are present along
the southern edge of the landfill. Concentrations decrease substantially with
distance away from the landfill. Concentrations of VOCs in groundwater
entering the wetland are low enough so as to not cause a problem to the
wetland.
D. ' Landfill Gas
The landfill does produce small volumes of landfill gas. Landfill gas is
predominantly methane and carbon dioxide. Concentrations of methane have been
detected in monitoring wells and gas vents at concentrations which exceed 25%
of the lower explosive limit. Methane is a combustible gas which can cause an
explosion under certain conditions. However, the risk of explosion is
extremely low at this site. There aren't any buildings or confined spaces
which would allow the gas to collect. The gas is vented to the atmosphere as
it leaves the site.
VI. SUMMARY OF SITE RISKS
The Wisconsin Division of Health completed a Public Health Assessment on the
Ripon FF/NN landfill. This document qualitatively identifies past, present
and future potential human health risks associated with environmental
contamination at the site.
The Public Health Assessment concludes that groundwater beneath and next to
the site is contaminated with VOCs at concentrations that could pose a health
hazard if this water were used for domestic purposes such as drinking. In
addition, leachate seeps along the eastern edge of the landfill could also
represent health risks were people to'come in contact with the seeps.
No one is currently using the contaminated groundwater. A house located
approximately 350 feet south of the landfill is no longer occupied. The water
supply well at this location has been abandoned and the house is vacant. Wis.
Adm. Code NR 812 forbids construction of a public water supply well within
1200 feet of a landfill. Therefore, no well will ever be installed at this
house in the future. Because the groundwater at this location is not being
used, and exposure to the leachate seeps is restricted, the site doesn't
currently pose a threat to human health.
The Public Health Assessment concludes that if use of the contaminated
groundwater for domestic purposes is restricted, and exposure to the leachate
seeps is eliminated, that the site will not pose a threat to human health in
the future.
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VII. ENVIRONMENTAL STANDARDS NOT MET AT THE SITE
The'Ripon FF/NN landfill does not meet the following applicable State
environmental standards:
NR 504.05(7), Wis. Adm. Code
Administrative code that requires facilities accepting waste which may
generate explosive gases must effectively prevent the migration of the
gas. The landfill has a gas venting system. However, the gas data from
monitoring wells MW-103 and MW-104 indicate that gas migration is taking
place.
NR 506.08(3), Wis. Adm. Code
Administrative code which states the Department may require the
concentration of explosive gases not exceed the lower detection limit
for that gas at the facility property boundary.
NR 445, Wis. Adm. Code
Administrative code that regulates the discharge of hazardous air
contaminants.
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NR 140, Wis. Adm. Code
Administrative code which regulates groundwater quality and actions
which must be taken to restore groundwater quality. Tables 5 and 6
within NR 140 list potential actions to be taken when preventive action
limits and enforcement standards are exceeded. Response actions listed
in both Tables include a change in the design or construction of a
facility, and a remedial action to prevent or minimize the further
discharge or release of substances to groundwater. Changes to the
landfill cover or gas removal systems would constitute a change in the
design of a facility.
The installation of a properly designed gas venting system will help the
landfill achieve compliance with the NR 500 series gas migration codes and NR
445 air discharge code. The new landfill cap and proper venting of the
landfill gas will help to achieve compliance with NR 140 by removing volatile
contaminants from the landfill before they are able to dissolve into the water
within the waste.
VIII. DESCRIPTION OF THE REMEDIAL ALTERNATIVES
A. Remedial Action Objectives
Remedial action objectives were developed for this site to address the source
of contamination, to provide short term and long term protection of human
health and the environment, and to meet applicable or relevant and appropriate
requirements. The site specific remedial objectives developed for this site
include:
* prevent direct contact with landfill contents
* reduce contaminant leaching to groundwater
* control surface water runon, runoff and erosion
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* prevent off-site migration of landfill gas
* restore groundwater quality to NR 140 standards
* . monitor groundwater quality, landfill gas and leachate for environmental
control.
B. Development of Alternatives
The remedial action objectives for this site involve limiting the potential
for exposure to contaminants via inhalation, ingestion, and dermal absorption
pathways, and controlling landfill gas emission and migration.
The remedial alternatives were assembled from applicable remedial technology
options. The alternatives surviving the initial screening were evaluated and
compared with respect to the nine criteria set forth in the National
Contingency Plan ("NCP"). In addition to the remedial action alternatives,
the NCP requires that a no-action alternative also be considered for the site.
The no action alternative serves primarily as a point of comparison for the
other alternatives.
C. Remedial Alternatives
Alternative A - No Action
Alternative B - Regrade Existing Landfill Surface
Alternative C - Construction of a Cover Layer on the Landfill
Alternative D •- Reconstruct the Clay Cap
Alternative E - Construction of a Composite Cap on the Landfill
Alternative H - Passive Landfill Gas Venting
Alternative I - Active Landfill Gas Collection and Treatment
Alternative J - Groundwater Extraction, Treatment and Discharge to
Surface Waters
Alternative K - Groundwater Extraction, Treatment and Discharge to an
Infiltration Gallery
Alternative M - Groundwater Extraction, Treatment at Ripon POTW
Alternative O - Construction of a Composite Landfill Cap and Passive Gas
Venting
A complete description of the various alternatives is provided in the
Feasibility Study. A brief description is listed below:
Alternative A - No Action Alternative
The No Action alternative is used as a baseline in which to compare
other alternatives against. Under this alternative essentially little
to no remedial actions are taken and the site is basically left as it
currently is. This represents the No Action alternative for both the
source control and groundwater operable units.
The only actions taken under this alternative would be general
maintenance of the site such as mowing and fixing erosion. A deed
restriction prohibiting excavation and other intrusive uses of the
property would be recorded in the Register of Deeds office. Monitoring
of the groundwater, leachate and landfill gas is also part of this
alternative.
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Capping Alternatives
The deed restriction, maintenance and monitoring activities listed in
Alternative A are also included with these alternatives.
Alternative B - Regrade the Existing Landfill Surface
This alternative would regrade the existing landfill surface to
eliminate the low areas and provide for proper drainage.
Alternative C - Construction of a Cover Layer
The existing landfill cover was constructed without a protective soil
layer above the clay. The purpose of the cover layer is to protect the
clay from freeze/thaw action, and to provide a rooting zone for surface
vegetation. This alternative would remove the topsoil and place a soil
layer above the clay. The topsoil would then be replaced and re-
vegetated.
Alternative D - Reconstruct the Clay Cap
The existing cover has approximately 2 feet of clay beneath
approximately 6 inches of topsoil. This alternative would strip off the
topsoil and as much clay as possible. A 2 foot clay layer would then be
constructed in accordance with NR 504.07, Wis. Adm. Code. The other
components of the soil cap listed in NR 504.07 would also be placed as
the cap is reconstructed.
Alternative E - Construction of a Geosynthetic Cap over the Landfill
Under this alternative, a composite cap would be placed over the
landfill. The cap would consist of (from top to bottom):
6 inches of topsoil with vegetation
18 to 30 inches of cover layer
a drainage layer
a plastic membrane
2 feet of compacted clay.
Gas Removal Alternatives
Alternative H - Passive LFG Venting
This alternative is designed to deal with LFG generated within the
waste. This alternative would construct vents through the waste. The
gas would enter the vent and then be discharged to the atmosphere. No
treatment or destruction of the gas would occur.
Alternative I - Active LFG Collection and Treatment
Under this alternative the LFG generated within the waste would be
actively collected through a series of gas extraction wells connected to
a blower. The gas collected by the system would be destroyed via a
flare.
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Groundwater Treatment Alternatives
These alternatives are designed to remediate the contaminated groundwater.
They could be implemented with both a capping and a gas control alternative.
Alternative J - Groundwater Extraction, Treatment and Discharge to a Surface
Water
Under this alternative, contaminated groundwater downgradient of the
site would be captured, treated and then discharged to a surface water
body. The most likely discharge points would be one of the wetlands
located northeast and southwest of the landfill.
Alternative K - Groundwater Extraction, Treatment and Discharge to an
Infiltration Gallery
This alternative proposes extracting groundwater, treating it, and then
discharging it to an infiltration gallery.
Alternative M - Groundwater Extraction, Treatment at the Ripon POTW
Under this alternative, groundwater would be extracted through pumping
wells. Water treatment and discharge would take place at the Ripon
POTW.
Alternative O - Construction of a Composite Landfill Cap and Passive Gas
Venting
This alternative essentially combines components of Alternative E and
Alternative H. A composite landfill cap would be placed over the
landfill surface. A gas venting system would be incorporated into the
composite cap to allow for the effective venting of gas to the
atmosphere.
IX. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
A. Introduction
U.S. EPA has established in the NCP nine criteria that balance health,
technical, and cost considerations to determine the most appropriate remedial
alternative. The criteria are designed to select a remedy that will be
protective of human health and the environment, attain ARARs, utilize
permanent solutions and treatment technologies to the maximum extent
practicable, and to be cost effective. The relative performance of each of
the remedial alternatives listed above has been evaluated using the nine
criteria set forth in the NCP at 40 CFR 300.430(e) (9) (iii) as the basis of
comparison. These nine criteria are summarized as follows:
THRESHOLD CRITERIA - The selected remedy must meet the threshold criteria.
1. Overall Protection of Human Health and the Environment
A remedy must provide adequate protection and describe how risks are
eliminated, reduced or controlled through treatment, engineering
controls or institutional controls.
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2. Compliance with Applicable or Relevant and Appropriate Requirements
(ARARs)
A remedy must meet all applicable or relevant and appropriate
requirements of federal/state laws. If not, a waiver may apply.
PRIMARY BALANCING CRITERIA are used to compare the effectiveness of the
remedies.
3. Long-term Effectiveness and Permanence
Once clean up goals have been met, this refers to expected residual risk
and the ability of a remedy to maintain reliable protection of human
health and the environment over time.
4. -Reduction of Toxicity, Mobility or Volume Through Treatment
The purpose of this criteria is to anticipate the performance of the
treatment technologies that may b6 employed.
5. Short-term Effectiveness
This refers to how fast a remedy achieves protection. Also, it weighs
potential adverse impacts on human health and the environment during the
construction and implementation period.
6. Implementability
This criteria requires consideration of the technical and administrative
feasibility of a remedy, including whether needed services and materials
are available.
7. Cost
Capital, operation and maintenance, and 30 year present worth costs are
addressed.
MODIFYING CRITERIA deal with support agency and community response to the
alternatives.
8. State Acceptance
After review of the Focused Feasibility Study and the Proposed Plan,
support agency's concurrence or objections are taken into consideration.
9. Community Acceptance
This criteria summarizes the public's response to the alternative
remedies after the public comment period. The comments from the public
are addressed in the Responsiveness Summary attached to this ROD.
B. Evaluation of the Remedial Alternatives
1. Threshold Criteria
a. Overall Protection of Human Health and the Environment
All of the capping alternatives provide a soil barrier which eliminates the
direct exposure to waste within the landfill. Fencing of the landfill will
also minimize potential exposure pathways by restricting access to the
landfill surface. The venting of landfill gas within the fenced circumference
of the site will reduce the exposure to landfill gas.
Alternative A - This alternative fails to control the migration of landfill
gas. Also, the landfill cover system currently on the site is allowing
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precipitation to enter the waste, collect contamination, and then enter
groundwater. The existing cap fails to stop this additional loading of
contaminants to groundwater. This alternative is not protective of human
health and the environment and will not be considered further for the source
control operable unit.
Alternative B - This alternative only slightly improves upon the existing cap.
Regrading the landfill surface will have minimal impact on reducing the amount
of precipitation entering waste and thus be available to affect groundwater
quality. This alternative is not protective of the environment and will not
be considered further.
Capping Alternatives (Alternatives C, D & E) - All of the capping alternatives
provide a barrier to the waste, preventing the direct contact exposure pathway
and reduce the amount of water entering the waste. Over the long term,
limiting the amount of water entering the waste will have beneficial effects
on groundwater quality. However, a capping alternative must be implemented
with a measure to remove gas from the landfill. By itself the landfill cap
doesn't provide all the necessary aspects to be a protective remedy. If
implemented with a gas removal system, then all of the capping alternatives
would provide source control that-is protective of human health and the
environment.
Gas Removal Alternatives (Alternatives H & I) - Removing the gas from the
landfill and venting it or destroying it are effective measures for
controlling landfill gas migration. However, these alternatives must be
implemented with one of the capping alternatives (Alternatives C through E).
If implemented with a landfill capping system, then either of these gas
removal alternatives would provide source control that is protective of human
health and the environment.
Groundwater Treatment Alternatives (Alternatives J, K & M) - These
alternatives involve removal and treatment of groundwater. From a groundwater
perspective, these alternatives are protective of human health and the
environment. However, Alternative A, the No Action Alternative for
groundwater would also be protective of human health and the environment since
adequate source control will greatly decrease migration of additional
contaminants to groundwater. Active groundwater restoration is then not
necessary at this site.
Alternative O - This alternative combines a capping alternative with a venting
alternative. This alternative is protective of human health and the
environment.
b. Compliance with Applicable or Relevant and Appropriate Requirements
(ARARs)
Capping Alternatives ( Alternative C, D & E) - These alternatives all help to
reduce the amount of water entering the waste. Minimizing the amount of water
entering the waste will improve groundwater quality. However, the
effectiveness in reducing the percolation of water varies with the design of
t-hese three .capping alternatives. These capping alternatives comply with all
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relevant and appropriate requirements related to capping and groundwater
quality.
Gas Removal Alternatives (Alternatives H & I) - These alternatives will
minimize the uncontrolled migration of landfill gas. The venting or
mechanical extraction of gas will comply with all relevant and appropriate
requirements related to gas migration.
Groundwater Treatment Alternatives (Alternatives J, K & M) - All of these
alternatives comply with all relevant and appropriate requirements related to
groundwater.
Alternative O - This alternative complies with all applicable or relevant and
appropriate requirements for capping, gas venting and groundwater quality.
This alternative is very effective at reducing infiltration, and will help to
achieve compliance with NR 140 groundwater standards within the shortest
possible time of any of the capping alternatives.
2. Primary Balancing Criteria
Alternatives which satisfy the two threshold criteria are then evaluated
according to the five primary balancing criteria.
A. Long-term effectiveness and permanence
Capping Alternatives (Alternatives C, D & E) - Capping a landfill is the most
effective method to reduce the amount of contamination potentially leaching
from the site. All of the capping alternatives will provide some measure of
long-term effectiveness and permanence. However, the membrane capping
alternative (Alternative E) is much more effective at reducing infiltration
into the waste when compared to the soil capping alternatives.
Gas Removal Alternatives (Alternatives H & I) - Both of these alternatives
offer long-term effectiveness and permanence. The passive system (Alternative
H) will be easier to maintain over the long term when compared to an active
gas extraction system. Also, the passive system would have greater
effectiveness over the long-term because once designed, it will operate in
perpetuity with very little annual maintenance required. An active gas system
is only effective as long as'it is operated.
Groundwater Treatment Alternatives (Alternatives J, K & M) - The groundwater
alternatives all offer long-term effectiveness and permanence assuming that
the active remediation systems would be run until they are no longer effective
at removing contamination from the groundwater. Assuming implementation of an
effective source control, minimal loading of contaminants to groundwater will
take place.
Alternative O - This alternative offers long-term effectiveness and
permanence. A membrane cap is very effective at limiting the amount of
infiltration entering the waste. A passive gas venting system, once designed
and installed, will effectively vent the gas as long as is necessary. A
membrane cap and gas venting system would be the most effective remedy to
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reduce the over all impact to the groundwater from the landfill and, will only
require simple, routine maintenance to keep acting as designed into the
future.
b. Reduction in Toxicity, Mobility or Volume Through Treatment
Capping Alternatives (Alternatives C, D & E) - Capping a landfill minimizes
the amount of infiltration that can enter the waste. This will reduce the
mobility and volume of contamination leaving the waste. However, this
reduction is not due to treatment.
Gas Removal Alternatives (Alternatives H & I) - Proper venting or physical
extraction of landfill gas will reduce it's mobility and keep the gas from
migrating offsite. However, this reduction is not due to treatment.
Alternative I, the active gas extraction alternative also involves destruction
of the captured gas in a flare. Combustion of the gas in a flare constitutes
treatment.
Groundwater Treatment Alternatives (Alternatives J, K & M) - An active
groundwater capture system will reduce the mobility and volume of contaminants
in groundwater. The captured water would be treated prior to discharge.
Alternative O - This alternative will greatly minimize the amount of water
entering the waste. This will reduce the mobility and volume of potential
contamination that may affect groundwater. The gas venting system will reduce
the mobility of landfill gas and keep it from migrating, offsite. However, the
improvements as a result of this remedy are not due to treatment.
c. Short-term Effectiveness
Capping Alternatives (Alternatives C, D & E) - These alternatives will reduce
the amount of contamination coming from the landfill by reducing infiltration
into the.waste. These benefits will occur immediately after the landfill caps
are in place. All of the alternatives could be implemented in a single
construction season.
Gas Removal/Venting Alternatives (Alternatives H & I) - These alternatives
will limit the migration of landfill gas. This benefit will occur after the
gas system, whether it be venting or active extraction, is in place. A gas
venting or extraction system can be implemented within a single construction
season.
Groundwater Treatment Alternatives (Alternatives J, K & M) - An effective
groundwater removal system will stop the spread of contaminated water. Any of
these alternatives can be implemented within a single construction season.
Alternative O - This alternative will reduce the amount of contamination
coming from the landfill by minimizing infiltration and by properly venting
landfill gas to keep it from migrating offsite. These benefits can be
realized within a single construction season.
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All of the alternatives listed above have short term adverse impacts related
to construction. All of the remedies include construction involving heavy
machinery, movement of large quantities of soil, and disturbing the existing
landfill cap. While using experienced contractors and proven construction
techniques can minimize these risks, any activity involving large equipment
can present potential hazards.
Another short-adverse impact due to these alternatives is increased truck
traffic during construction. The capping alternatives will involve bringing
soil and other materials to the site. This will increase truck traffic along
Highways FF and NN creating the potential for traffic accidents with residents
living near the site, or with trucks from the active sand & gravel quarry
across the street from the site.
d. Implementability
Capping Alternatives (Alternatives C, D & E) - All of the capping alternatives
are readily implementafale using established construction techniques and
materials.
Gas Removal/Venting Alternatives (Alternatives H & I) - The gas removal
alternatives are all readily implemented using established construction
techniques and materials.
Groundwater Treatment Alternatives (Alternatives J, K & M) - All of the
groundwater removal and treatment alternatives are readily implementable using
established construction techniques and materials.
Alternative O - This alternative can be readily implemented using established
construction techniques and materials.
All of these remedies will require some level of oversight by WDNR. Because
of the common nature of these remedies, the remedies can be implemented
without excessive administrative burdens.
e. Costs
Alternative C
Capital Costs - $631,000
Annual Costs - $33,000
Present Worth - $1,085,.000
Alternative D
Capital Costs - $850,000
Annual Costs - $33,000
Present Worth - $1,304,000
Alternative E
Capital Costs - $1,171,000
Annual Costs - $33,000
Present-Worth - $1,625,000
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Alternative H
Capital Costs - $161,000
Annual Costs - $33,000
Present Worth - $202,000
Alternative I
Capital Costs - $165,000
Annual Costs - $19,000
Present Worth - $427,000
Alternative J
Capital Costs - $167,000 to $219,000 depending upon discharge location
Annual Costs - $50,000
Present Worth - $855,000 to $907,000 depending upon discharge location
Alternative K
Capital Costs - $170,000
Annual Costs - $51,000
Present Worth - $872,000
Alternative M
Capital Costs - $269,000
Annual Costs - $46,000
Present Worth - $898,000
Alternative O
Capital Costs - $1,220,000
Annual Costs - $34,000
Present Worth - $1,688,000
3. Modifying Criteria
a. State Acceptance
The WDNR is the lead agency on this case and authors this ROD.
b. Community Acceptance
The WDNR received one comment during the public comment period. This comment
urged WDNR to consider the cost of the remedy and the burden to pay for this
remedy on the responsible parties. A formal response to this comment is
provided in the Responsiveness Summary attached to this ROD. However, the
WDNR believes this remedy is cost effective and represents a balanced,
practical solution to the environmental problems posed by this site.
c. Summary
The landfill cap that currently exists on the site is not very effective at
limiting the amount of infiltration entering the wastes. Of the capping
alternatives proposed, the composite cap will be most effective at minimizing
precipitation into the waste. Over the long term, limiting the amount of
water entering the waste will have beneficial effects on groundwater quality.
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The waste does produce a small volume of landfill gas. Gas generation rates
are not high enough to warrant an active landfill gas removal system. A
properly designed gas venting system will limit the migration of landfill gas
and greatly diminish any explosion hazard associated with the gas. Also,
because of the small volume of gas generated by the site, the gas can be
safely vented to the atmosphere without causing any exceedances of air
emission standards.
Alternative O, along with an effective groundwater monitoring program,
provides all of the factors necessary for a source control remedy which is
protective of human health and the environment, complies with ARARs and is
cost effective. The composite cap will greatly reduce infiltration when
compared to a soil cap. This will have beneficial effects over time and
warrants the additional cost of a composite cap relative to a soil cap. A
proper gas venting system will limit landfill gas migration and remove
contaminants present in the gas making them unavailable to dissolve into the
leachate. The low gas generation rates don't warrant construction of an
active gas extraction and treatment system.
Groundwater contamination does exists at the site. However, it's impacts are
fairly limited. Contaminated groundwater is present between the site and the
wetland to the southwest of the site. Concentrations of VOCs, namely vinyl
chloride and cis 1,2-DCE are high near the waste boundary, but diminish
greatly with distance from the site. VOC concentrations in the groundwater
discharging to the wetland are low enough so as not to cause an adverse impact
to the wetland. Active groundwater restoration efforts are not necessary for
this site. A groundwater monitoring program that detects changes in
groundwater quality, and is part of the source control remedy, provides
protection to nearby residential wells and also works to make this remedy
protective of human health and the environment. Therefore, the WDNR has
determined that it is not necessary to supplement Alternative O with a
groundwater removal and treatment alternative in order to comply with ARARs
and achieve protection of human health and the environment. Therefore,
Alternative A, the No Action Alternative for groundwater is the best solution
for the groundwater operable unit at this site.
CONCLUSIONS OF LAW
The source control remedy, Alternative O, will protect human health and the
environment, complies with all legally relevant and appropriate requirements
for this site, and is cost effective. Alternative 0 utilizes alternative
technologies to the maximum extent practicable, but does not satisfy the
statutory preference for treatment as a principal element.
Alternative A, the No Action alternative for the groundwater operable unit, is
protective of human health and the environment, complies with all applicable
or relevant and appropriate requirements for this site, and is cost effective.
The extent of groundwater contamination from this landfill is minimal and
doesn't warrant active groundwater remedial measures.
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A. Protection of Human Health and the Environment
The selected remedies provides protection of human health and the environment
through capping to contain the wastes, which will alleviate threats from
direct contact and minimize leachate generation. Proper venting of the gas
will limit the migration of gas offsite. An effective groundwater monitoring
program will detect changes in groundwater quality, and make certain that
contamination from the landfill doesn't affect nearby private wells.
B. Attainment of ARARs
The selected remedies will be designed to meet all applicable, or relevant and
appropriate requirements under federal and state environmental laws. Since
the Ripon FF/NN landfill is a state lead cleanup, no CERCLA on site permit
exemption is available. All permits and approvals required to implement the
remedies must be obtained and strictly complied with. The primary ARARS that
will be achieved by the selected remedies are:
1. Action Specific ARARs
Wisconsin Statutes, section 114.43 to 144.47
Wis. Adm. Codes, ss NR 504.05(7), NR 504.07(3), and NR 508.04 - landfill gas
control. Standards for landfill gas control and monitoring practices. These
requirements are applicable to the landfill gas venting system at the site.
Wis. Adm. Code, ss NR 514.07 and NR 516 - Landfill closure requirements.
Substantive requirements for the design, construction, upgrading, maintenance
and documentation of landfill caps. Cap design, construction, maintenance and
documentation must comply with these applicable requirements.
Wis. Adm. Codes, ss NR 508.04 and NR 140 - Groundwater monitoring
requirements. Substantive requirements for groundwater monitoring plans must
meet these applicable requirements.
Wis. Adm. Code, NR 600 series - Hazardous waste requirements. This code was
enacted to regulate the transportation, storage and disposal of hazardous
waste. This code is neither applicable, nor relevant and appropriate for this
site.
RCRA, Subtitle D - Solid waste requirements. Subtitle D are federal
regulations enacted for solid waste disposal. The regulations are applicable
to facilities which accepted waste after October 9, 1991. The Ripon FF/NN
landfill closed in 1983. The Subtitle D regulations are neither applicable,
nor relevant and appropriate for this site.
2. Chemical Specific ARARs
Clean Air Act [42 U.S.C. 7401 et seq.]; Wisconsin Statutes, sections 144.30
to 144.426
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40 CFR 50; Wis. Adm. Code, chs. MR 404, NR 415 to NR 449 - Emission Standards.
Standards for emission of pollutants into ambient air and procedures for
measuring specific air pollutants. Cap construction could cause air emissions
of VOCs, particulate, fugitive dust or other contaminants which could
adversely affect human health and the environment. The design of the remedy
must reduce air emissions to acceptable levels or provide treatment to satisfy
these applicable standards.
Wis. Adm. Code, NR 140 - Groundwater Quality Standards. The remedy is
designed to reduce the amount of contamination entering groundwater and
achieve compliance with standards found in NR 140.
C. - Cost Effectiveness
The selected remedies call for overall'cost effectiveness. While the
composite landfill cap costs more than a soil cap, it is also much more
effective in limiting infiltration into the waste. Less infiltration
translates into less leachate production and this will have beneficial effects
on groundwater quality. The additional cost of the composite landfill cap
will significantly increase the remedy's effectiveness by reducing
infiltration.
The site isn't producing .enough landfill gas to warrant an active gas
extraction system. A properly designed gas venting system will effectively
remove gas from the waste, and prevent it from migrating offsite or collecting
in an area where it may pose an explosion hazard.
Groundwater contamination near the landfill is not severe enough to warrant an
active groundwater remedial system. VOC concentrations decrease rapidly with
distance from the waste boundary. An effective monitoring plan will track the
changes in VOC concentrations with time, and make sure that contaminants don't
affect residential water supply wells near the site.
D. Utilization of Permanent Solutions and Alternative treatment
Technologies
The selected alternatives represent the best balance of the alternatives with
respect to the nine criteria. The cap eliminates the direct exposure pathway
and reduces the amount of leachate that will be generated by the waste. The
gas venting system will vent the gas to the atmosphere at levels low enough
not to cause any problems. Capping and venting are both permanent solutions
for a landfill.
E. Preference for Treatment
The selected remedies don't satisfy the preference .for treatment. However,
capping the landfill, venting the landfill gas and monitoring the groundwater
quality represents a practical solution for this site.
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DECISION: THE SELECTED REMEDIES
Based on an evaluation of the alternatives, the Wisconsin Department of
Natural Resources believes that Alternative O, the selected source control
operable unit remedy, and Alternative A, the selected groundwater operable
unit remedy, are protective of human health and the environment, comply with
ARARs, are cost effective and use permanent remedies to the maximum extent
practicable.
The selected source control operable remedy includes:
* constructing a composite landfill cover (i.e. a landfill cap made with
both a plastic membrane and soil materials) over the entire landfill
* installing a passive landfill gas venting system as part of the
composite cap to effectively vent landfill gas from the waste
* monitoring of the groundwater quality to determine the effectiveness of
the landfill cap towards improving groundwater quality
* monitoring the landfill gas probes around the landfill to make sure that
landfill gas is not migrating away from the site in an uncontrolled
manner.
* maintenance of the landfill cap to repair erosion that may develop
* a restriction on the property deed prohibiting disturbing the landfill
cap except for maintenance purposes
* fencing of the landfill perimeter to restrict access
At the 5 year evaluation of the remedies, a report documenting the following
items shall be prepared and submitted to WDNR:
1. A summary of all groundwater quality data. Special mention should be
made of changes in water quality and a comparison of the data to
groundwater quality standards in NR 140.
2. A summary of all gas monitoring data.
3. A summary of all maintenance which has occurred to the cap or gas
extraction system.
4. An evaluation as to whether the selected remedies are helping to improve
groundwater quality, maintain a barrier to the waste, and properly vent
gas from the site.
This report shall be submitted to WDNR by January 15, 2001.
The WDNR has determined that the selected source control operable unit remedy,
Alternative O,- and Alternative A, the selected groundwater operable unit
remedy, will achieve the remedial action objectives for this site.
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RESPONSIVENESS SUMMARY
The public comment period for the Ripon FF/NN Landfill Superfund site ran
between August 31, and September 29, 1995. The WDNR received one comment
during the comment period. A copy of the comment is attached to this
Responsiveness Summary.
The main point of the comment is that the WDNR consider whether the proposed
remedy is too costly in light of the identified need. The comment points out
that the Public Health Assessment recommends that the site have a monitoring
plan, that leachate in the site be controlled to prevent seepage, and that
site access be restricted. The commentor believes that these goals can be
achieved in a less costly manner than that proposed by WDNR.
The WDNR believes that the selected remedies for source control and
groundwater are not excessive measures to achieve the recommendations made in
the Public Health Assessment. WDNR believes that control of leachate within
the site will be most effectively maintained with the composite cap. The
composite cap will essentially eliminate movement of water into the waste,
something that a soil only cap is unable to do. This will in turn essentially
eliminate leachate generation. Leachate is the source of contamination to
groundwater. Stopping the creation of additional leachate will stop the
movement of contamination into the groundwater. Even though it is limited in
it's extent, groundwater contamination is present at the site. Eliminating
further leachate generation will have beneficial effects on groundwater
quality. Improving groundwater quality is clearly one of the remedial
objectives for this site. The WDNR believes that the increased effectiveness
of a membrane cap make it worth the additional cost when compared to the cost
of a soil only cap.
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September 13, 1995
Memo for Steve Ales, Project Manager or "To Whom It May Concern":
This is a written response to your public hearing tonight which I cannot
attend because of a prior engagement.
Writing both as a member of the common council and as head of one of the
participating P.RPs, I wish to urge that the DNR think kindly about Ripon and
that a prescribed "cleanup action" be reasonable.
It would be very important to those of us who must pay the -bill for
"capping" this site to insist on an appropriate "cost benefit" program. One
that none of us will be able to label as "overkill.
A predicted cost of $1.2 million (plus annual maintenance or other coses
of $34,000) as now recommended by the DNR seems excessive to this writer.
This is stated keeping in mind the recently released "Health Assessment"
report filed with the city by the Wisconsin Department of Health and Social
Services working with the U.S. Department of Health and Human Services (Agency
for Toxic Substances and Disease Registry).
This report recommends action, of course. However, it states that "No
community health"concerns related to the site have been reported" (page 16).
"Current information about the site indicates that existing private wells are
not likely to be threatened by groundwater contamination from the site."
Nevertheless, it recommends that a monitoring plan be established (Page 17).
In it's recommendations, it states 1. the need for a monitoring plan,
(certainly a reasonable suggestion) 2. that leachate in the landfill should
be controlled to prevent possible seepage and 3. that site access should be
limited.
This would be fulfilled with your Alternative 0, I appreciate. However,
I would like to urge that the DNR consider a less expensive method for
achieving Number 2 above (controlling the materials--leachite-- in the site.)
No doubt you will be discussing these alternatives at the meeting
tonight. I certainly hope so, and I hope local PRPs are on hand to offer
input.
I would just like to urge consideration for the public and corporate
pocketbook and that the remedy be simply appropriate to the identified need
and not excessive and heavy handed.
Sincerely,
Doug Lyke,
Alderperson City of.Ripon
Chairman of Ripon Community Printers
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