The first development at the Altamont Landfill and Resource Recovery
Facility (ALRRF), Unit 1, was unlined. As a result of a large storm
event that occurred during the first year of filling, a sizable leachate
seep contaminated groundwater in the canyon below. At some future point,
the RWQCB placed ALRRF in an evaluation monitoring program (EMP), and
then in a corrective action program (CAP).
As a corrective action, a groundwater interceptor barrier (GWIB) was
constructed at the mouth of the canyon. The GWIB is essentially a French
drain with pumps that cuts across the alluvium and keys into bedrock.
Groundwater at the site is controlled by topography and ends up in the
alluvium. The GWIB has been pumped since the late 1980s, with quantities
ranging from 100,000 gallons per year to 1 million gallons per year. The
volume of water pumped has been trending lower over the last few years.
In conjunction with this decrease in volume, there have not been any
detections in the last several quarters. The owner thinks that the
recharge area for where the plume was generated has been cut off due to
capping a large portion of Unit 1 and that the plume has essentially
been cleaned up. This year a technical memorandum was put together
requesting to shut down the GWIB. The RWQCB is requiring monitoring of
the GIWB for a couple of years after the shutdown, including monitoring
for water levels and annual sampling for constituents. Formally, the
site is still in CAP, but the owner is implementing the first step of a
multistage process to assess the need for continuing corrective action.
Unit 1 predates the regulatory minimum requirements for containment
systems, and all construction that postdates Unit 1 meets or exceeds all
existing minimum regulatory requirements. The regulations do not limit
the site in meeting these requirements. The owner and the RWQCB have had
some disagreements concerning site-specific geology and where to locate
groundwater monitoring wells. This has resulted in more well
installations than would have been otherwise required.
In 1999, the RWQCB issued a notice of violation (NOV) stating that
groundwater monitoring was not up to standards in Title 27, California
Code of Regulations. A series of waste discharge requirement (WDR)
revisions have been issued to resolve groundwater monitoring well issues
and to come to an agreement between the owner and the RWQCB. Overall,
the owner feels that the environmental protection in place at the site
is sufficient, and that additional protection is provided by favorable
geologic conditions at the site.
The owner asserts that in general, the regulations allow sufficient
protection of the environment. However, the interpretation of the
regulations has changed over time. This site has been required by the
RWQCB to demonstrate performance of prescriptive minimum base liner
prior to construction. It is expected that liner performance evaluations
will also be required for future expansion if the prescriptive minimum
base liner system is proposed.
The owner believes the current standard
on landfill liners, wherein the discharger must demonstrate to the
regulators that the prescriptive minimum base liner system meets
performance standards, is in excess of the regulations. However, on a
statewide level, the standard may make some sense when considering
landfills with different geologic conditions (for example, artesian
groundwater conditions, excessive leachate, or a usable water supply)
that might warrant going above and beyond the prescriptive requirements.
The site has a landfill gas collection system and landfill gas probes
around the waste perimeter. As long as the vacuum is kept up in the
system, there have not been any problems at the probes. Some hits occur
if the vacuum drops. Some of the probes were actually installed through
waste, but there is currently a plan to move them to the perimeter.
Explosive gas monitoring devices are in all structures. A survey of all
probes is performed once a quarter.
The owner considers the regulations reasonable; however, there is
some confusion in relation to the location of monitoring probes. There
appears to be an inherent assumption in the regulations that the
"property boundary" will be close to the landfill footprint. For a site
like ALRRF, where the property boundary in some areas is over a mile
away from the waste boundary, this assumption makes no sense. Monitoring
locations should be performance-based, as they are at ALRRF. Distance
from the waste boundary and site geology should be considered in
establishing the location of the probes.
ALRRF is much more aggressive with landfill gas than minimum
regulatory requirements because the owner looks at gas as an asset for
power production. The owner is planning to produce liquefied methane. In
addition, ALRRF has collaborated with a tire shredding operation and is
evaluating the synergies of gas collection, recycling of tires, and
power production all in one. This is part of an overall project in which
the owner develops gas collection systems in the ongoing fill process,
using shredded tires and collection pipes. The net result is that ALRRF
manages its waste stream, improves gas production, and enhances gas
collection.
ALRRF has very little runoff from the landfill. Due to the semi-arid
environment, the daily volume of new waste (which is very absorbent),
and site operations, leachate ponding is rarely seen, even during rain.
If any leachate seeps occur, they are handled promptly. No steps above
the regulatory minimums have been necessary to handle leachate or
drainage/erosion control. The site has found that ground green waste can
be a valuable erosion control tool, whereas hydroseeding can be
difficult due to the alkalinity of the site soils. The ground green
waste forms a mat, providing initial erosion control protection and
ultimately acts as a good source for vegetative growth.
Although not related to Title 27, the owner commented on the State
Water Resources Control Board’s Statewide Implementation Plan (SIP) that
establishes standards for discharge of process waters. The new process
water discharge requirements have essentially rendered the ALRRF’s water
treatment plant useless for discharge of treated leachate, as the plant
cannot meet many of the inorganic requirements. As such, the treated
leachate is stored onsite and used for dust control, although not during
rainfall events as it could become mixed with surface water runoff. The
discharge requirements make it difficult for ALRRF during periods of
significant rain when the facility has to store treated leachate at the
same time that the site is generating the most leachate.
As described previously, ALRRF has invested heavily in, and is very
aggressive about, extracting gas from the landfill. There are five
different control systems for the landfill gas collection system,
resulting in redundancy in the system. The site can have several of
these control systems down at the same time and still maintain enough
vacuum on the system to stay compliant. The ALRRF is one of the only
landfills in the country with this level of emissions control.
The owner has received notices to comply (NTC) or notices of
violation (NOV) from the air district, but generally not for the gas
collection system. One difficulty is that there are 30 different sources
on site for ALRRF’s "Title V" permit, and the recently issued Title V
permit did not calculate emissions accurately for some sources due to a
BAAQMD rush to issue the permit before December 1, 2003. The resulting
permit issued immediately contained compliance issues which have
resulted in a series of requested changes by the district to the BAAQMD.
The owner does everything it can to identify problems and address them,
but cannot run a perfect system. As such, they receive violations. The
owner asserts that there has never been a serious air violation at the
site, and none of the NOVs has resulted in excess emissions from the
site.
The owner believes that the regulatory process relating to the gas
collection system could be simplified. At present, every gas collection
well requires a separate permit modification for installation or
removal. Owners should be able to install and remove wells as needed to
ensure that the performance or air quality standard is being met. In one
year, for example, an owner may want to take 20 wells out and put 20
wells in, and currently needs a permit to obtain a permit for this
action.
Gas collection devices do not do anything to increase emissions, they
are the abatement device. The waste buried in the landfill is the source
of the emissions. The site should therefore not need a permit for these
types of modifications to the gas collection system. The owner believes
that this requirement has been adapted from requirements for other
sources that do not fully apply to landfill conditions (e.g.
refineries). The difference between a landfill and a refinery is that a
refinery is processing more to increase their output. A landfill is
about controlling an existing amount of emissions (decomposing waste).
The two should be treated differently.
The owner stated that regulations can typically be easily implemented
if all parties are communicating freely throughout the process.
The CAP at the site relates to the unlined portion of the site and
the groundwater interceptor barrier (GWIB), which has been in place
since the late 1980’s. The unlined portion of the landfill is partially
closed (the face is closed, but the top deck is still open). The site
has had no detections for over a year, and the owner has recently asked
to cycle the GWIB on and off to see what effect this has on groundwater.
In conjunction with their aggressive landfill gas extraction program,
the RWQCB felt a pilot study cycling the GWIB off and on seemed
justified. The ultimate goal of the pilot study would be to turn off the
GWIB, because the site has been collecting and treating large volumes of
water for many years.
The owner is starting the pilot study for cyclic operation of the
GWIB, and if the results are positive, they will attempt to prove its
performance under cyclic operation. The proof period is typically three
years according to the regulations. If ALRRF passes the proof period,
the site would head out of corrective action into detection monitoring.
In order to pass the proof period, ALRRF will have to have no detections
during sampling events. The regulations allow a concentration limit
above background, but in order to apply that criterion, the owner would
have to do a study of backgrounds levels. The analytical costs of such a
study are high, and the expected backgrounds are zero when the
contaminants are volatile organic compounds (VOC). If the backgrounds
were not zero, there would likely be another source of contamination.
At ALRRF, there have been some issues with interpretation of
regulations by the RWQCB versus the owner. The disagreements relate to
the hydrogeological model for groundwater flow at the site. The RWQCB
wants to ensure that all potential pathways for contaminant migration
are evaluated. There has been disagreement over what the potential
pathways are and hence where the point of compliance is.
One comment on landfill regulations that is applicable for all sites
relates to the timeframe for clean-up of a release. It is hard to have
owners provide a compliance date for cleanup completion. There should be
a mechanism in the regulations for establishing a date for completion of
corrective action so that it does not run indefinitely. If the owner and
the RWQCB are working together, there would be updates of the corrective
action every six months and the RWQCB would know whether the date was
going to be met or not and whether modifications to the compliance date
are warranted. A timeframe for completion of the CAP has not yet been
included in the WDRs for ALRRF. However, as discussed previously, the
Owner is currently implementing a program to evaluate the effectiveness
of the CAP to date, and the regional water quality control board (RWQCB)
has considered incorporating a timeframe into future WDRs for the site.
Title V of the Clean Air Act (Title 42, U.S. Code,
section 7401, et seq.). Title 40, Part 70 of the Code of Federal Regulations
provides for the establishment of comprehensive state air quality permitting
systems consistent with the requirements of Title V. 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.
