NCD980602163_19971125_Warren County PCB Landfill_SERB C_Draft Response to Non-Compliance-OCR

State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Waste Management
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
William L. Meyer, Director November 25, 1997
DELIVERED VIA FEDERAL EXPRESS
Ms. Carol L. Kemker, Chief
Pesticides and Toxic Substances Branch
US Environmental Protection Agency, Region 4
Atlanta Federal Center
100 Alabama Street, S.W.
Atlanta, Georgia 30303-3104
DRAFT
SUBJECT:
DOCKET NO.:
RESPONSE TO NOTICE OF NON-CO1\1PLIANCE
TSCA-4-97-11844
Dear Ms. Kemker:
The State ofNorth Carolina, Department of Environment and Natural Resources, Division
of Waste Management, has responsibility for the maintenance of the PCB landfill in Warren
County, NC, permitted by the EPA in 1981 under the Toxic substances Control Act (TSCA).
This agency has received the Notice of Non-Compliance (NON), Docket Number TSCA-
4-97-11844 for violations of that permit. Enclosed herein are our responses to that NON.
As you are aware, the Division, in conjunction with the Warren County PCB Working
Group (WG), has expended considerable resources on the landfill during the last two years as we
have been studying the potential for detoxification. To date, these efforts have been focused in
three areas: 1) Site Investigation 2) Bench scale pilot study of detoxification technologies 3)
Phase II, Preliminary Draft Design.
During the Site Investigation, 18 new monitoring wells, including 3 off site background
wells, were installed. Two bore-holes were placed in the landfill from which soils were extracted
for the detoxification studies. Extraction wells were installed in the bore-holes and are now
monitor~d hourly for changes in water levels. Extensive sampling and analysis has taken place
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P.O. Box 29603, Raleigh, North Carolina 27611-9603 Telephone [phone]
An Equal Opportunity Affirmative Action Employer 50% Recycled / 10% Post-Consumer Paper
DRAFT
on all of the monitoring wells, landfill soils, leachate, surrounding surface soils, sediment and
stream samples. Some samples were split with the EPA, Athens Lab. A draft copy of the Site
Investigation and copies of all sampling results have been sent to Mr. Craig Brown in your office.
Two companies and two technologies were selected for pilot studies--ETG
Environmental using Base Catalyzed Decomposition (BCD), and ECOLOGIC using a chemical
dechlorination process. Following the results of this "Phase I" study, the Working Group, as
recommended by their Science Advisors, selected the BCD technology as the one for
detoxification. ETG is now working on a Phase II report which will be a draft remedial design
plan for detoxification of the landfill. Once completed (anticipated in mid-January), the WG and
Division will put together a plan to seek funding for detoxification. The Department of
Environment and Natural Resources is committed to pursuing detoxification.
We anticipate various committees of the North Carolina General Assembly to begin
meeting in March of l 99~th a short session beginning in May of 1998. It is unknown at this
time iffundinlc'a'jfb~5~tamed, however we should know by July 1 if funding will be available.
There is a possibility that the request may have to wait until the long session in January of 1999.
The State of North Carolina will fund all activities required to come into compliance with
the NON. We do not anticipate any problems associated with the activities scheduled between
now and July of next year, specifically implementation of our Phase 1 plan. We have put together
a response to fully comply with the NON requirements of a Phase 2, should that be necessary.
In response to Violations # 1 & #2, the Division has already implemented testing as
required at the landfill. The monthly testing on the leachate, since August, has included PCBs,
pH, and specific conductance. The first round of semi-annual testing for 1997 was conducted this
past spring and included these parameters. The second round of semi-annual testing was
conducted on November 17 & 18. In addition to the monitoring wells, surface water and
sediment samples previously sampled, we have added all of the new wells which are strategically
located around the landfill. This monitoring is discussed in detail in the attachments.
Violation #3 is discussed in detail in the attachments. The Division intends to do
considerable testing on the pump rates and re-charge rates of the leachate collection system,
including the two new extraction wells. Once we determine a sustainable pumping rate, we will
design an automatic pumping system to continuously remove water from the landfill. This will
facilitate detoxification and meet permit conditions. It is our belief that the leachate collection
system does function properly, however, the transmissivity of the LCS is a problem because of the
low permeability of the soils transmitting water to this layer. Utilization of the extraction wells
will help in the removal of the water, but the process could take several years to complete.
2 DRAFT
DRAFT
A contingency plan (Phase 2) for replacing the landfill cover system is attached which
could be implemented ifwe are unable to secure funding for the detoxification and fail to submit
an alternate method for PCB disposal next summer.
We appreciate EPA working with us on this project. The State ofNorth Carolina is
committed to insuring that we are in compliance with the TSCA permit. Please contact Mr.
Michael Kelly at [phone], extension 203 , if you have any questions regarding this
response.
Copy: Henry Lancaster, DENR
Michael Kelly, DWM
PCB Working Group
3
Sincerely yours,
William L. Meyer
Director
Division of Waste Management
DRAFT
RESPONSE TO NON FROM EPA, TSCA-4-97-11844
APPENDIX 1
VIOLATION #1: MONTHLY MONITORING OF LEACHATE
The letter of approval for the PCB landfill, dated December 14, 1981, requires monthly
monitoring for leachate quality and quantity, and proper disposal of collected leachate. The state
was exempted from the requirement to test for chlorinated organics, however, is required to test
for PCB, pH and specific conductance. Although the state has performed certain monthly
monitoring and checks on the leachate, it has not conducted ph and specific conductance on a
routine basis.
The state has the specific field equipment necessary to perform on-site testing for pH and
specific conductance, and will begin immediately to insure that these tests are done each month.
Under normal circumstances, DWM personnel perform testing and inspection of the landfill
during the last two weeks of the month. All results of analysis will be submitted to the EPA
within 30 days of the testing beginning with the November 1997 sampling event.
The leachate will be pumped, sampled and discharged according to the permit conditions
utilizing the current equipment on-site (ie gas powered diaphragm pump) until the new equipment
discussed in Violation #3, Leachate Collection System, can be designed and installed. It is
anticipated that this phase will be operational by June of 1998. At that time, the state should
begin routine, continuous pumping ofleachate from the LCS and the two bore-holes installed this
spring in the PCB landfill. This de-watering of the landfill will most likely be a long term event,
and used to facilitate detoxification as well as meet permit conditions.
VIOLATION #2: SEMI-ANNUAL MONITORING
The state is required by it's permit to do extensive semi-annual monitoring of the surface
water and groundwater at the site. This sampling is to be specific for PCBs, ph, and specific
conductance. Although the state has done continuous monitoring at the site for PCBs, it has not
completed sampling on a routine basis (ie monthly or semi-annually) for pH and specific
conductance.
In April and November of 1997, the state performed extensive sampling at the landfill.
The April sampling was done as a part of the Site Investigation. Results of that event have been
sent to Mr. Craig Brown of your office. EPA personnel from the Athen's lab were present during
part of the sampling and split some samples with the state.
4
DRAFT
The November sampling event (conducted November 17 & 18) was specific to the semi-
annual requirement. Samples were taken from monitoring wells and surface water. In the past
the state sampled the original 4 monitoring wells located around the landfill. Beginning this year,
with the installation of new wells at the site, we will use only three of the previous wells, # 1, #2
and #3, and add five of the new wells which are directly around the landfill, adjacent to the fence.
These wells are numbered #IA,# 5D, #7, #11 and #12. Field instruments are being used for pH
and specific conductance.
All results will be forwarded to the EPA as soon as they are available. Future testing for
the semi-annual events will occur in the spring and fall.
ADDmONAL SAMPLING AND TESTING
As previously discussed, the state is working closely with the PCB Working Group in
pursuit of detoxification. During the next few months, as we implement the various tasks to
insure compliance at the landfill, we will also incorporate various other tests designed to help
monitor the conditions of the landfill . These tests will be aimed at air and groundwater.
METHANE TESTING
On two occasions this year, the state has "gridded" off the perimeter of the landfill,
plugged the top eight inches and systematically checked for methane. The landfill generates gas
as part of the natural decomposition of organic materials present, and is nearly always detected in
the vent pipe and bore-holes (extraction wells) at the landfill.
The issue of airborne particulate matter containing PCBs is a concern of the Working
Group. Any such particulate matter escaping from the landfill may be expelled by "belches"of
gases from the landfill. There is also a concern over the condition of the landfill cap.
The DWM will perform routine monthly monitoring for methane gas, and extensive
quarterly monitoring around the perimeter of the landfill in an effort to detect any possible
breaches in the cap through which methane gas may be escaping.
DIOXIN TESTING
There were a variety of dioxin compounds which were detected in numerous samples
taken this past spring. Two of the monitoring wells close to the landfill, #IA and #5D, showed
positive hits for several of the dioxin compounds which are similar to compounds that were found
in the landfill. Although considerable discussion was made on dioxin in the Site Investigation
Report, the state cannot draw any conclusions from the data.
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Additional testing for dioxin will be conducted during the next semi-annual event on
selected wells, including #IA and #5D, the leachate, and at least one of the background wells.
AIR MONITORING
There has been a great deal of concern over the potential for airborne particles
contaminated with PCBs "belching" from the landfill. The state has conducted two air sampling
events using PUF filters and both low flow and high volume air pumps. One sample showed a
positive for PCBs. The concentration was extremely high, and therefore suspected as not being
valid since no other samples, including one directly beside it and the sample from inside the landfill
showed any detectable levels of PCB.
Personnel monitors were used during the site work last spring, both during the excavation
of soils and installation of extraction wells, and cutting of the plastic liner for testing. None of
these samples were positive. EPA, likewise, performed high volume sampling over a 24 hour
period in August, and no PCBs were detected.
In December of 1996, a carbon filter was placed on the vent pipe at the landfill to insure
that any particulate emanating from the landfill through the vent would be trapped. Concern is
now primarily over the possibility of particulate being belched from the landfill through cracks or
faults in the cap. Methane monitoring should assist in the identification of any cracks or failures
in the landfill cap.
The state will perform air monitoring routinely at the landfill and at a minimum perform a
quarterly 24 hour high volume sampling event.
WEATHER STATION I WATER LEVEL MEASUREMENTS
The state has installed a weather monitoring station at the landfill to record temperature,
barometric pressure and rainfall. Additionally, monitoring devices have been placed in both
extraction wells to measure on an hourly basis the water level in the landfill.
An on-site computer system records the data which is downloaded currently on a monthly
basis by DWM personnel. Analysis of the data will include correlations between barometric
pressure and rainfall with the level of water inside the landfill . Continuous monitoring of the
water level in the landfill will provide useful information on the integrity of the cap and any
infiltration I exit of water into or out of the landfill .
The division has plans to add to the monitoring at least one of the monitoring wells
outside of the landfill.
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VIOLATION #3: LEA CHA TE COLLECTION SYSTEM
SUBJECT: PCB Landfill, Warren County-Analysis of geotechnical testing results, and
evaluation of remedial alternatives for the existing leachate collection system.
INTRODUCTION
In 1993 the state reported that of water was present in the landfill. Water was measured in the
leachate collection sump riser. Calculations were made as to the volume of water based simply on
the reported results of measured water levels in the leachate collection line and using assumed
porosities and saturations of the landfill contents. Two bore holes were advanced in the landfill in
February of 1997, for the purpose of removing soils for bench scale testing of PCB detoxification
technology. Wells were installed in the bore holes and are currently being continuously monitored
for water level changes. Soil samples were taken at intervals in the landfill during the drilling
process. Standardized geotechnical tests were performed by an independent testing laboratory.
The tests included determination of grain size, density, moisture content and permeability.
In September of 1997 the USEP A issued a notice of non-compliance to the state. One of the
issues cited was that the state was in violation of a permit condition which requires that the
leachate be pumped to maintain the head on the bottom liner system to less than one foot. This
report is in response to that notice. The State proposes a three phase approach to bring the landfill
back into compliance with its operating permit. The three phases are:
• Analyze existing data to calculate the theoretical properties of the landfill, including
moisture content, porosity, yield, and capacity and yield of the leachate collection system.
• Perform pump tests on the existing leachate collection system and the two wells in the
landfill. The results will be compared to the theoretical values and pump sizes and ancillary
equipment will be specified and obtained.
• Install automatic pumps to extract the moisture from the landfill and discharge it through
the existing permitted on-site treatment and irrigation system.
This report contains the evaluation of the existing data obtained from the landfill investigation and
from ongoing continuous monitoring. A proposal for implementing phase two of the remediation
is presented and a conceptual plan for the actual pumping is also contained herein.
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DRAFT
ANALYSIS OF EXISTING DATA
To effectively design a method for removing water in the landfill it is necessary to evaluate the
new data about the landfill which was obtained during the February 1997 site investigation at the
subject facility. Data also exists from an ongoing continuous monitoring program which the state
is currently conducting at the landfill . The analysis will :
• Determine how much moisture is in the landfill,
• The characteristics of the material within which the moisture resides,
• The theoretical transmissivity of the leachate collection system(LCS)
Moisture Content-
Samples were obtained from the landfill during the boring program in February. Seventeen jar
samples, obtained from split spoon sampling, and ten undisturbed samples obtained from shelby
tubes were analyzed for moisture content in accordance with ASTM D2216 testing protocols.
The tests indicated that the landfill has an average moisture content of 14% by mass. Converting
this weight of water to a volume indicates that there are about 1. 86 million gallons of moisture in
the landfill, and the average moisture content, on a volumetric basis is 23%(vol/vol).
In 1982 moisture tests were performed on samples obtained from four borings in the landfill. The
samples were taken after large amounts of rain and before final closure of the landfill. At that time
the reported moisture contents were of a wider range 5-20%, but still average 13 .6% by weight.
This translates to approximately 1.85 million gallons of moisture. The moisture content in 1982
was 22.4% (vol/vol).
Total Porosicy-
The bulk density, dry density and specific gravity of the landfill contents were obtained by testing
samples from ten shelby tubes. The specific tests methods used were ASTM Dl587, D2937 and
D854 respectively. The total porosity of the landfill can be calculated using the dry density and
specific gravity of the material. The total porosity of the system has been determined to be 35%.
Clearly the moisture content of the landfill (23%) is less than the porosity (35%), so the landfill is
not saturated with water. During sampling of the landfill, visual observations of the split spoon
samples confirmed this . There was no free water which drained from the landfill materials that
were collected in the split spoons or shelby tubes.
Effective Porosicy-
The effective porosity of the landfill soils was calculated using the grain size analysis results
(ASTM D422) and plotting the results on a triangle chart produced by Johnston (1967). The
effective porosity or specific yield of the soil is a measurement of how much water an aquifer will
yield or give up under gravity drain conditions. It was determined that the landfill has a calculated
effective porosity of 18% (vol/vol).
8
Field Capacity-
The field capacity of the soil is a measurement of how much water a soil will absorb or hold. If the
moisture content of the soil is below the field capacity then water will not gravity drain out of the
soil and if it is above it will. The field capacity was determined using empirical equations EPA
(1994). The field capacity of the landfill contents is 22%( vol/vol)
Available Moisture-
What is immediately evident is that the landfill is just barely above field capacity and only slightly
more than the estimated specific yield. One percent of the volume of the moisture is only 133,000
gallons, while 5 percent is 655,000 gallons. Thus while the moisture content of the landfill is
estimated to be I. 86 million gallons, only 1-5 percent is estimated to be available for removal.
Permeability-
Shelby tubes oflandfill contents were obtained and permeability tests (ASTM 5084) were run on
them. Slug tests were also performed on one of the bore holes. The test results indicate that the
permeability of the landfill contents is on the order of 1x10·5 cm/sec.
Transmissivity of LCS-
Calculations were made of the theoretical transmissivity of the leachate collection system, the
sump, and the two wells in the landfill.
The transmissivity of the landfill leachate collection system is 0.015 gal/min/sqft, a small amount
of water. It is important to note that the controlling factor in removing the water from this landfill
is not the transmissivity of the leachate collection system but the low permeability of the soils
transmitting water to this layer. Much has been made about the lack of pipes in the landfill, but
they would not significantly increase the amount of water collected since the amount transmitted
to the LCS is controlled by the landfill contents.
The maximum transmissivity of the bore hole wells is 0.32 gal/min/sqft, each. This assumes a ten
foot level of available moisture and an effective diameter of O. 698 feet. As moisture is removed
from the system, the length of the column will decrease and the flow will decrease accordingly.
LEA CHA TE COLLECTION SYSTEM TESTING
It will be necessary to perform pump tests on the leachate collection system and the two bore
holes to provide information that will be used in the final design of the system that will be
proposed for long term remediation of the existing LCS. The theoretical calculations indicate that
the yield on from the system is low. One goal of the tests will be to see if there is a sustainable
pumping rate at which the system can be continuously run.
9
Method-DRA FT
To gather the data that is needed, several simple pump tests will be performed. Low volume,
adjustable flow rate pumps will be employed. The first step will be to pump the test point dry, and
then measure how long recharge takes. In the second round of tests, continuous pumping will be
experimented with to determine if there is a pump rate at which sustained levels of pumping can
be done.
The specific type of pump, and whether it will be placed in the landfill or will reside atop the
landfill will be determined by availability of equipment. The existing downhole sensors can be
used to monitor the recharge of the bore holes.
Treatment-
Treatment and disposal of the leachate recovered during the pump test is of prime concern. The
leachate could be discharged through the existing permitted treatment system. It is envisioned for
this test that external treatment be used. The low flows expected can easily be treated with small
filtration equipment. This will be used since it is unknown how much sediment is in the leachate.
The use of staged equipment will allow for easy monitoring of the treatment process and an ability
to determine the amount of sediment in the leachate.
A series of three sediment filters will be used . Initially the size of the sediment filters will descend
from 10 to 5 to 1 microns. The leachate will then pass through a packed bed filter of granular
activated carbon. The clean water will then be discharged through the existing permitted leachate
collection treatment system for final discharge to the sedimentation basin.
When the sediment filters need to be replaced, they will be removed from the filter housing and
put in double plastic bags. They will then be stored in a drum, onsite, prior to final disposal at an
approved disposal site.
LEACHATE REMOVAL
The results of the pump test will be used to properly design and specify the elements of a leachate
removal system. It is anticipated that the existing leachate collection sump riser and the two new
bore holes will be equipped with low flow pumps, which will be activated by water level sensors.
The leachate will be treated and discharged through the existing permitted treatment system. The
existing treatment system will be evaluated to determine if any of the components need to be
replaced or upgraded, prior to actual startup . At the anticipated low flow rates the water may be
treated and discharged to the sedimentation basin or stored in a tank and later used to irrigate the
vegetation on the landfill.
The previous calculations have demonstrated that the amount of recoverable water in the landfill
is relatively small. Constant pumping of the leachate should return the landfill to compliance with
its operating permit. The amount of time this is expected to take will be determined after the
pump tests are analyzed.
10 DRAFT
Removal of available moisture from the landfill will also benefit any future plans to detoxify the
landfill contents. The proposed detoxification method is a thermal treatment process. Any
moisture that can be removed from the system should aid in lowering energy costs for the
process, since that is a volume of water that will not have to be boiled off during the treatment
process. It will also lower the amount of water and waste products that will have to be collected,
tested and disposed of, as a result of the detoxification process.
REFERENCES-
Johnson, A.L.(l 967)" Specific Yield-Compilation of Specific Yields for Various Materials".
Geological Survey Water-Supply Paper 1622-D. Washington D.C.
Schroeder, P .R., Dozier, T.S., Zappi, P.A., McEnroe, B.M., Sjostrom, J.W., and Peyton, R.L.
(1994). "The Hydrologic Evaluation of Landfill Performance (HELP)Model:Engineering
Documentation for Version 3," EPA/600/R-94/168b, USEPA Risk Reduction Engineering
Laboratory, Cincinnati, OH.
11
PHASE 2: CAPREPLACEMENT
Monitoring well information indicates water level fluctuation is influenced to a far greater
degree by ambient air pressure rather than infiltration. The investigation earlier this year also
indicates that while the synthetic cap membrane has degraded, overall, it still provides relatively
good, while not perfect, protection from infiltration.
If a cap is required, we would recommend the following (listed from the bottom of the cap
to the top):
• Leave the existing 10 mil PVC cap and underlying clay in place.
,r\J ,~~-
The existing pvc liner and clay liner will act as a-v.ery effect-we redundant system. With
installation of an additional synthetic liner and drainage layer, infiltration to the existing
pvc cap should be effectively eliminated.
• Remove approximately I foot of the vegetative and erosion control cover to eliminate
organic matter and roots.
• Rework (shape, compact) the remaining cover to provide a suitable sub-base for additional
cap layers.
• Install a 60 mil HOPE synthetic cap layer. The difference in cost between 40 mil and 60
HOPE is nominal. The 60 mil thickness provides greater security in seaming, puncture
resistance, and degradation.
• Install a fabric bonded HOPE single layer drainage net. These types of drainage nets
provide an extremely transmissive drainage layer effectively eliminating head (water
column) on the HOPE liner.
• Provide a continuous drainage collection system around the perimeter of the HOPE
drainage net. This would be a simple 'french' drain which is connected to the drainage net.
• Discharge collected rain water to a sedimentation and erosion control pond(s) separate
from the existing structure. This will allow for separate constituent monitoring if necessary
in the future.
• Install a 2-foot vegetative and erosion control layer. The previously removed erosion
control layer material can be incorporated into this new layer.
• Seed and mulch the new erosion control layer.
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In addition to installing the above cap system, passive methane venting would be installed.
Venting systems typically consist of collection pipes embedded in rock filled trenches just below
cap systems and vented to vertical stand pipes.
For the PCB landfill, this would require breaching the existing PVC liner and clay cap to
install the vents.
To minimize disturbing the existing cap, alternative venting should be explored as a part
of the request for proposals solicited for the final design of the additional cap system.
In a caveat to the above presented preliminary design, the preliminary nature must be
emphasized. A final design would depend upon analysis and recommendations presented by the
engineering consultant once one is selected through the RFP process. For example~ it may be
found that methane venting could be accomplished utilizing the existing monitoring wells and vent
pipe.
In addition, decisions on landfill de-watering can affect the design in terms whether or not
the existing wells are utilized. Handling of leachate, if sprayed on the cap for example, would
affect the final design.
As all actions taken at the landfill can affect other elements and designs, any cap design or
other component design presented at this time must be considered preliminary and subject to
change.
If it is determined that cap or other improvements are necessary, the RFP development
and selection process should provide information needed to refine final designs.
13
APPENDIX 2
SCHEDULE OF COMPLIANCE
RESPONSE TO NON FROM EPA, TSCA-4-97-11844
VIOLATION #1: MONTHLY MONITORING
Start date: August, 1997
Monthly monitoring, usually done during the last two weeks of each month.
Items measured: Leachate
Parameters: PCBs, pH, specific conductance
Leachate system: To be pumped at each visit until continuous system installed.
Additional monitoring for methane
VIOLATION #2: SEMI-ANNUAL TESTING
Start date: April, 1997
Most recent: November 17-18, 1997
Occurrence: Semi-annual testing to be in the spring and fall of each year.
EPA to be notified of actually dates.
Parameters: PCBs, pH, specific conductance*
Additional monitoring for Dioxin--selected wells
Locations: All approved surface water and sediment sources.
Monitoring wells--I, IA, 2, 3, 5D, 7, 11, 12**
Leachate , inlet and outlet
• Parameters for liquids; solids PCBs only
**Change in some well locations; addition of wells installed in spring of 1997 around
perimeter of the landfill .
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VIOLATION #3: LEA CHA TE COLLECTION SYSTEM
Start date: November, 1997, removal of water using existing LCS and pump
Occurrence: Monthly until installation of continuous pumping system
New pump system:*
Pump testing
Design and RFP
Plan to EPA
Contract issuance
Installation
In service
January 1998
February 1998
March 1998
April 1998
May 1998
June 1998
*Plan to include utilization of current LCS and both extraction wells installed in March
1997.
PHASE2: CAPREPLACEMENT
A preliminary design for cap replacement is included in the Appendices. Cap replacement
will occur if funding for detoxification is not received. It is understood that EPA desires cap
replacement if an application for alternate PCB disposal for the landfill soils is not received by
August 27, 1998.
Funding for detoxification
Decision for detox/ cap replacement
Final design for cap
Submittal to EPA
RFP
Issuance of contract
Begin Construction
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March-June 1998
July 1998
July 1998*
August 1998
September 1998
November 1998
January 1999