CIWMB’s Solid Waste Information System (SWIS) number: 35-AA-0001
Site Information per
Landfill Facility Compliance Study (Task 2)Information Source: Owner/Operator:
(County of San Benito)
Telephone conversation: April 2, 2004
E-mail responses: April 12, 2004 and May 20, 2004
Monitoring wells were installed and volatile organic compounds (VOC)
were detected during the solid waste assessment test in the late 1980s.
The source of the VOCs was found to be an old mixed deposit of Class I
and Class III waste placed prior to the establishment of regulations for
segregating hazardous and municipal wastes. A separate unlined Class I
landfill adjacent to the unlined Class III area is closed, and has not
been found to be the source of any groundwater impacts.
The site has a complicated geologic structure. The groundwater flow
conditions vary from one side of the site to the other, with different
conditions beneath the Class I and Class III areas.
The corrective action order was combined with the postclosure permit
for the Class I Landfill. This means that the corrective action is being
regulated by the Department of Toxic Substances Control (DTSC) with the
approval of the regional water quality control board (RWQCB). The
overlap between these agencies was cumbersome under the site’s old
post-closure permit. However, the RWQCB is the designated lead agency as
the result of legislation passed in 1993 (Chapter 1184, Statutes of
1993, Umberg, AB 2061), which established a process for designating an
administering agency to oversee the cleanup of a contaminated site. The
two agencies have been working much more effectively since this
legislated chain of command has been emphasized. Otherwise, the
groundwater regulations have been implemented easily and effectively at
this site.
There are new waste discharge requirements (WDR) for the site (more
current than the 1994 WDR requirements included in the CIWMB landfill
study’s cross-media inventory) dated 2002 (Permit No. 2002-0001).
The corrective action for the site consists of four extraction wells
(two onsite and two offsite), from which groundwater is pumped and
treated and discharged to the publicly owned treatment works (POTW). The
site has seen improvement since the implementation of the corrective
action; the offsite wells are no longer detecting any VOCs and only one
constituent is being detected in the onsite wells.
The original gas control system consisted of 5 monitoring probes, 5
extraction wells, and a flare. The gas control system has recently been
expanded (17 new extraction wells and 5 new monitoring probes) in
response to a possible gas migration impact on two groundwater
monitoring wells. A new, larger flare is on order.
The previous gas-related violations and enforcement actions at the
site have been inter-related with the air quality violation. The air
district found that the flare was in violation and shut it down. In
response, some of the monitoring wells (one of which was installed very
close to the waste) went out of compliance because gas extraction was
stopped. This led to gas-related violations from the local enforcement
agency.
Recently, the site has been in violation of gas control requirements
again, because the new flare was not ordered soon enough to handle the
capacity from the new extraction wells. Extraction was stopped from one
side of the landfill (the side not impacting the groundwater wells)
until the new flare is installed. The monitoring wells on this side are
now exceeding limits.
Part of the problem with this site is that the waste is placed right
up to the property boundary. The gas-related violations started to occur
at the same time that discussions were going on within the regulatory
agencies (with respect to Billy Wright Disposal Site) about the impacts
of buying additional buffer property around landfills in order to comply
with landfill gas requirements. The site is very remote and adjacent
buffer property was available, but because the owner did not sense the
RWQCB was taking a clear stance on the acceptability of purchasing
buffer property to comply with gas control regulations, the
owner/operator did not obtain the buffer.
Another difficulty with regulating remote sites like John Smith Road
comes when defining a “nuisance” or “hazard” with respect to gas control
issues. What may be a “nuisance” or “hazard” in an urban setting may
have little or no impact in a remote, rural setting.
The site has a permit to operate issued by the air pollution control
district (APCD) for the existing gas control system, and the owner has
authorization to construct the expansion (new, larger flare). A
violation was issued by the APCD in March 2003. This violation was
resolved by installing a new control panel to continuously read the
flare temperature, and the flare, which was having mechanical problems,
was reset to maintain the permitted temperature. At the higher reading,
carbon monoxide (CO) emissions were within limits upon retest. The
county received and paid a fine for the noted violations. This problem
occurred during the transition to a new contract operator.
The owner indicated that the leachate control violations in 1998 and
1999 may have been associated with grading issues at the site, but was
not certain.
Information Source: Central Coast Regional Water Quality Control Board
E-mail responses, April 27, 2004 and May 19, 2004
Groundwater beneath the site occurs within the three geologic units.
In locations where the upper portion of the Panoche Formation is
overlain by alluvium, a hydraulic connection exists, and both units
behave as a single aquifer. Hydraulic conductivities range from 3 x 10-3
to 5 x 10-5 centimeters (cm)/second (sec) (3100 feet per year to 52 feet
per year). Hydraulic conductivities in the 10-3 cm/sec range are typical
of values used for Class III landfill leachate drainage layer design.
Within the Panoche Formation, flow occurs primarily along fractures.
The present monitoring system consists of 4 Class I and 18 Class III
groundwater monitoring wells. These wells are sampled on a semi-annual
to annual basis. Twelve additional wells are used for water level
measurements for both the Class I and Class III areas. As discussed
below, several wells located down-gradient from the Active Class III
Area have been impacted.
Groundwater is not in contact with waste or contaminated soil beneath
the closed Class I facility. Non-contaminated soil was confirmed at
approximately 745 feet mean sea level (MSL). Beneath this point, the
groundwater potentiometric surface is typically between 710 and 720 feet
MSL. Since the Class I area has been closed with a composite final
cover, water infiltration (the main contaminant driver toward
groundwater) has been significantly reduced or has ceased.
Groundwater has periodically been in contact with waste in the
central portion of the Class III facility. The base of refuse was
determined to be at an elevation of approximately 665 feet MSL in the
boring for abandoned well WA-21 (east of well W-5). At this location,
groundwater has been present at elevations between approximately 660 and
680 feet MSL. However, seasonally high groundwater elevation in the
expansion area is 12 feet below the proposed bottom of waste. This
satisfies the minimum separation requirement of five feet between
groundwater and waste.
In 1985, the owner signed consent agreements with DTSC and the U.S.
Environmental Protection Agency (U.S. EPA) to close the Class I area and
to characterize soil and groundwater contamination in both the Class I
and Class III areas. The result of this investigation indicated the
presence of VOCs in groundwater below the Class III area. In 1987, an
additional investigation was performed which indicated that VOC
contamination extended off the landfill property. In 1988, the RWQCB
issued Cleanup and Abatement Order No. 88-31 (CAO 88-31), which required
additional off-site groundwater characterization.
In 1989, the owner entered into a consent agreement with the U.S. EPA
specifying the work to be performed at both the Class I and Class III
portions of the site. The consent agreement required the owner to
conduct groundwater monitoring at the Class I area and a facility
investigation and corrective measures study for the Class III area.
These investigations concluded that the primary source of VOC was
leachate from the Class III area.
In 1993, remedial measures were implemented to mitigate groundwater
impacts. The mitigation consisted of controlling the source, mainly
leachate extraction and hydraulic containment of the on and off-site
plume. Leachate wells LW-1 and LW-2 (both subsequently abandoned) and
groundwater extraction wells EW-1, EW-2, and EW-3 were installed. Later,
EW-4 was installed to provide additional hydraulic containment of the
on-site contamination.
In August 1995, the California Environmental Protection Agency, at
the owner’s request, designated the RWQCB as the lead administrating
agency for the site. The RWQCB is responsible for the implementation of
all applicable laws governing site investigation and remediation, in
consultation with DTSC.
In June 1996, the U.S. EPA issued a final decision for the Class III
landfill. The final decision, which was included in the DTSC Class I
post-closure permit, included the on-site and off-site containment and
source control strategies. In August 1996, the U.S. EPA notified the
discharger that all further corrective action work should be addressed
through the DTSC Class I post-closure permit.
Currently, groundwater impacts extend approximately 700 feet off-site
to the northwest. Limits of the plume are defined by monitoring wells
WA-20 (contamination detected) and CP-25 (clean). Recently, groundwater
and the vadose zone have shown impacts from landfill gas. The owner has
been required to expand the on-site gas recovery system to address these
impacts and to prevent further groundwater degradation.
Over the past 14 years, VOC concentrations have been decreasing. The
decreasing trends are likely in response to on-site and off-site
groundwater removal, and minimization of storm water infiltration into
waste. The U.S. EPA requires this site to have groundwater contamination
under control by 2005. Recently, the U.S. EPA determined the site did
not have groundwater contamination under control. This finding was made
because the extraction system had been shut down.
The extraction system had been shut down for about two years prior to
2000. Construction of a new access road near two of the wells
necessitated the shutdown, but it is not known why the wells were not
immediately returned to service once construction had ceased. The wells
were returned to service only after a staff change occurred at the San
Benito County Solid Waste Authority. Pumping resumed in 2000, and the
system has been subsequently upgraded by adding pump savers. Since the
wells were only returned to service in 2000, staff continues to watch
for any significant increases in VOC concentrations.
VOCs have recently been detected in wells not associated with the
corrective action. An amended report of waste discharge (ROWD) was
submitted in November 1999 and an engineering feasibility study
submitted in May 2000, which concluded that recently detected VOCs
(vinyl chloride—C2H3Cl) in Well W-4 were related to landfill gas. Since
that time, one other trace detection has been reported in Well E-15,
which is an up-gradient well for the Class III area. The discharger
recently expanded the landfill gas system to address impacts at W-4. The
discharger is currently optimizing the system and is submitting monthly
reports. The RWQCB will continue to monitor corrective action progress
and overall site compliance.
Information Source: Enforcement Agency (County of San Benito, County
Health Department, Environmental Health Division)
Telephone interview, April 5, 2004
The enforcement agency (EA) indicated that the violations in the
period 2000 and 2001 were in response to explosive gas concentrations
greater than 5 percent in gas monitoring probes during routine
monitoring. Although some of these violations were labeled as violations
of Title 27 of the California Code of Regulations, section 20919 (gas
control), the issue was actually explosive gas (section 20919.5). For
this site, an explosive gas control violation occurred during two
consecutive quarterly monitoring events in 2000. The EA subsequently
increased the site’s gas monitoring to monthly intervals. Until the gas
control system was upgraded, the violations continued on a monthly basis
throughout 2000 and the beginning of 2001.
According to the current regulations, if a site has violations during
three consecutive monitoring events, the site may be listed on the CIWMB
Inventory of Solid Waste Facilities Violating State Minimum Standards.
This site was listed on the inventory in 2000. After the EA wrote a
letter in March 2001 to request removal of the site from the list
because the explosive gas control issues had been resolved, the site was
removed from the inventory.
A stipulated notice and order was previously issued to formalize the
mutually-agreed-upon resolution to the gas-related issues at the site,
and to provide a timeline for compliance. This type of enforcement
action allows more flexibility than others, such as a cease and desist
order. The stipulated notice and order expired in 1998 and a notice and
order was written in 2000 to replace it. A notice and order generally
carries more weight than a stipulated notice and order.
A stipulated order of compliance and agreement was issued January 22,
2000, requiring the site to lower concentrations at the boundary to
below the lower explosive limit (LEL) and to monitor concentrations if
the LEL was exceeded. The timeline associated with this enforcement
action required submittal of a plan by February 21, 2001, and full
compliance with gas control regulations by March 23, 2001.
The expansion of the site’s gas extraction system was partly in
response to the gas control issues, but may also have been in
anticipation of installing a larger flare. An increased acceptance rate
is expected to increase gas generation, and the larger flare may be
necessary to handle the destruction of the increased volume being
extracted.
Some new gas-related violations have occurred since November 2003.
These violations are related to explosive gas hits in some of the new
perimeter monitoring wells while the new larger flare is on order. The
installation of the new flare, and associated increase in gas
extraction, is expected to correct the problem.
The EA was unfamiliar with the leachate control areas of concern
(1998 and 1999) because they occurred before his involvement with the
site. The EA indicated that there have been no surface water or leachate
control issues since his involvement at the site.
With respect to regulatory compliance issues, the permitting process
has been problematic due to the involvement of an additional agency. The
site is also under the jurisdiction of DTSC, so there is an additional
step in the permit approval process. Specifically, the process of
permitting grading and access near the Class I / Class III boundary in
2001 was more difficult than expected.
Information Source: Monterey Bay Unified Air Pollution Control
District
Telephone interview: April 1, 2004
A permit has been issued for the gas destruction system. The only
jurisdiction the APCD has is over the gas destruction system, to protect
against the emission of greenhouse gases from the system. Due to the
size of the landfill (2.3 million cubic meters), this site does not have
a Title V permit. However, the site has been approved for a volume
increase which will require a Title V permit (volume greater than 2.5
million cubic meters), including the additional record-keeping and
monitoring requirements.
The site has been issued one notice of violation (NOV) since the
beginning of the study period (January 1, 1998). The NOV, dated March
18, 2003, addressed the following issues:
- Exceeding the CO emission limit of 0.4 pounds/one million
British thermal units for the landfill gas flare, as required by
condition 3 of the permit to operate.
- Failing to maintain a minimum combustion temperature of 1400°
Fahrenheit for the landfill gas flare, as required by condition 6 of
the permit to operate.
- Failing to continuously record the combustion temperature during
the landfill gas flare operation, as required by condition 7 or the
permit to operate.
The APCD did not identify how the issue was resolved.
Title 40 of the Code of Federal Regulations, Part 70
provides for the establishment of comprehensive state air quality permitting
systems consistent with the requirements of Title V of the Clean Air Act
(Title 42, U.S. Code, section 7401, et seq.). These regulations define the
minimum elements required by the Clean Air Act for state operating permit
programs and the corresponding standards and procedures by which U. S. EPA
will approve, oversee, and withdraw approval of state operating permit
programs.
List of Landfills
|
