CIWMB’s Solid Waste Information System (SWIS) number: 43-AM-0001
Site Information per
Landfill Facility Compliance Study (Task 2)Information Source: Owner/Operator: City of Palo Alto
E-mail responses: March 12,2004 and April 28, 2004
Although the Palo Alto Landfill has no geosynthetic liner, it is
extensively underlain by Bay Mud, a particularly impermeable soil
deposit whose hydraulic conductivity has been measured at 1 x 10-6
centimeters per second. The groundwater monitoring well system
completely surrounds the site and has been in place since 1989
(additional wells have also been added since 1989). Monitoring wells are
sampled quarterly for volatile organic compounds (VOC) and other metals
and water quality parameters. Since this system's inception, no VOCs
been positively detected, and all other inorganic parameters have not
exceeded their concentration limits. The City of Palo Alto Landfill leachate system was extensively evaluated
in 1994 and 1995, and since that time less extensive but fruitful
evaluations have been conducted each year. Based on those evaluations,
the city has replaced and added extraction wells and piezometers to the
system. The owner is also budgeted for a general system-wide overhaul of
the leachate system expected to be in progress and completed by fiscal
year 2004/2005. During this upgrade, the owner will be replacing six
extraction wells and three piezometers and replacing the backbone of the
main line with high density polyethylene (HDPE) piping. The leachate
collection system is permitted to extract and discharge up to 4 million
gallons per year of leachate to the regional water quality control plant
sewer system, making it a very effective groundwater protection measure. Regarding the enforcement action for not meeting minimum landfill
gas-related standards, in the past, the City of Palo Alto’s gas
monitoring probes were indicating high levels of methane. The
owner/operator investigated and found they were installed in refuse. The
city, the EA, and CIWMB decided that they were ineffective at monitoring
because of this condition. The CIWMB allowed the city to install another
monitoring system in locations that were not compromised by older refuse
deposits. The CIWMB approved the new system, and it has been operating
for four years without a problem. The owner is scheduled to overhaul the landfill gas (LFG) collection
system in fiscal year 2004/2005. The overhaul will entail replacing and
adding new wells and replacing the main header pipelines with HDPE
piping. The LFG electrical cogeneration plant with reciprocating internal
combustion engines has been operational since 1989. The system consists
of two 1-megawatt engines that convert LFG into electricity. Tax credits
went away for gas-to-energy, so it is no longer as economically viable
at this site. The decline in electricity prices has also hurt the
affordability to create electricity. For gas-to-energy, reclaiming BTU
content of gas while controlling it has had both economic and
environmental benefits. Regarding the leachate control area of concern noted in the cross-media
inventory, the site had a leachate pipe that broke in August 1995, and a
spill occurred. The city repaired the pipe as soon as possible, but
still received a fine from the RWQCB. The city paid the fine. No other
action has resulted from the incident. With regard to surface water related issues at the site, the
owner/operator indicated that often ponding is the result of landfill
settlement. Decomposition processes in the landfill cells causes the
surfaces sometimes to collapse and form low areas. Whenever the
owner/operator encounters these areas, they are repaired as quickly as
possible. No notices to comply (NTC) or notices of violation (NOV) have been
issued for air quality issues at the site.
Information Source: Regional Water Quality Control Board, San Francisco
Region
Telephone conversation: March 18, 2004
The site is in compliance and the regulations. The latest information
from the RWQCB is in Waste Discharge Requirement (WDR) Order 99-026,
which rescinded the previous WDR Order 88-038 to bring the site into
compliance with Title 27 of the California Code of Regulations.
Information Source: Enforcement Agency—Santa Clara County Department of
Environmental Health
Telephone conversation: March 9, 2004
E-mail response: April 28, 2004
Regarding the site’s previous areas of concern, violations, and
enforcement actions regarding compliance with the LFG control
regulations, the problem was not LFG control-related but instead was
traced to LFG probes being installed in waste at the established
facility boundary. The city owns two adjacent facilities: one is used as
the landfill; the other is a publicly owned treatment works (POTW)
(sewage treatment plant). All of the land under both facilities was used
for landfill operations in the distant past by the city. At the
landfill, a violation arose because probes installed at the facility
boundary were detecting gas, and this problem was interpreted as gas
migration. After researching the history of the site, it was determined
that there was waste outside the facility boundary; therefore, the gas
being detected was likely not from the current landfill operations, but
from past operations. After the problem was understood and because both
facilities are owned by the city, a decision was made to move the
facility boundary to encompass the waste outside the current landfill.
New probes were installed around the new compliance boundary. The new
compliance boundary was established outside of the landfill facility
operating boundary and included all of the old waste. There is an operational gas collection and extraction system at the
site. The gas is used to power a cogeneration plant with turbines that
are used to produce some electricity. At one time, a component of the leachate control system broke. This
resulted in a surface discharge of leachate. The broken component was
repaired before it reached the estuary. Regarding inspections for
drainage and erosion, the same individual performs monthly inspections.
The results are standardized for continuity. Inspectors are trained to
look for the same things and follow similar procedures. Areas of Concern
(AOC) related to surface water were minor (such as ponding and erosion)
and were fixed by the operator as needed. Ponding is usually due to
ditches that become flat with time. Another identified AOC was a
leachate pipe that was fixed before any major problem developed.
Information Source: Bay Area Air Quality Management District
Telephone conversation: March 16, 2004
E-mail response: March 30, 2004
The air quality management district (AQMD) regulates 50 landfills and
landfill gas combustion facilities in the Bay Area. The landfill
facilities include 20 active sites and 16 sites that are no longer
accepting waste. Out of the 36 landfills, 19 sites are known as
designated facilities that are subject to federal requirements for
municipal solid waste (MSW) landfills in addition to AQMD requirements.
To be a designated facility, the site shall have accepted waste after
November 8, 1987 and shall have an overall waste capacity of at least
2.5 million megagrams and 2.5 million cubic meters. The City of Palo
Alto Landfill is one of these 19 designed facilities. The AQMD and federal regulations require subject landfills to collect
and control LFG. These regulations specify surface leak limits for the
landfill and establish performance standards for the LFG collection and
control systems. Other AQMD regulations limit particulate emissions from
active sites, limit secondary emissions (such as nitrogen oxides, carbon
monoxide, sulfur dioxide, and particulate matter) from combustion
operations, and may also impose limits on ancillary operations. The City
of Palo Alto Landfill has been equipped with landfill gas collection and
control systems since 1994. These collection and control systems are
designed to meet both AQMD and federal requirements. The City of Palo
Alto Landfill has been generally operating in compliance with all
applicable requirements. During the last 10 years, the AQMD has
identified a few isolated instances of non-compliance with an AQMD
requirement. These non-compliance incidents are discussed in more detail
below. The AQMD issued four NOVs to the City of Palo Alto Landfill in the last
10 years. All the violations were associated with AQMD performance
standards for the landfill gas collection and control systems. The NOVs
included two collection system component leaks (one in 1997 and one in
2000); one unauthorized well disconnection (in 1998); and one violation
of permit conditions concerning the LFG flare combustion temperature
limit and monitoring requirements (in 2000). The site operator responded
quickly to correct the violations after the violations were discovered,
and has been diligently monitoring site operations to prevent future
violations. The AQMD has not issued NOVs for any operations at this site
since November 2000. About half of the collected LFG is delivered to an off-site facility,
where it is used as fuel in engines that produce energy. The off-site
engines are not experiencing any problems.
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