Groundwater Cleanup – Page 2 – Alameda Point Environmental Report

Navy cleans long-gone gas stations

The Navy has spent more than 15 years cleaning up contaminated groundwater underneath two former gas station sites at Alameda Point. They are still at it, but it’s not because the Navy is slow or lacking in commitment and expertise. It’s the nature of groundwater cleanup, which involves intermittent treatment efforts.

In July, the Navy’s contractor returned to the old gas station and car wash site on West Pacific Avenue at Main Street and to the old commissary gas station site at West Tower Avenue and Main Street across from Bayport. It’s the third visit to these sites to eliminate petroleum hydrocarbon contamination in groundwater, in addition to earlier removal of underground tanks, fuel lines, and soil. The contaminants are located from 2 to 16 feet below ground surface.

Workers at the old gas station and car wash site on West Pacific Avenue on July 13, 2015 preparing to inject cleanup solutions into the ground. The Navy operated a gas station and car wash on the site from 1971 to 1980. Green tank on truck contains non-potable water for on-site mixing of treatment solution. Soccer field is in the background.

The goal is to bring the property up to the public health and environmental standards required for the future commercial and residential uses previously determined by the city.

“When groundwater contamination is involved, such as at the two former gas stations, cleanups often involve multiple phases, each building upon earlier accomplishments,” said Dr. Peter Russell, who has been reviewing Navy cleanup plans and preparing cleanup-related documents on behalf of, and at the direction of, the city since 1997. “As long as all imminent health and environmental risks are eliminated early on, often the most cost-effective approach to complete remediation is incremental,” explained Russell. “In contrast, a massive initial remedial effort that is sure to achieve all remedial goals in one pass would likely involve over-sizing the treatment system, which is more disruptive and expensive than a phased approach.”

During previous cleanup visits, the Navy used a vapor extraction system to remove the bulk of the petroleum contamination. The process involves pumping air into numerous pipes, called wells, which extend into the water-saturated zone where the contamination is. The air pressure creates vapor that is part air, part water and part petroleum. The vapor is then sucked out through another set of wells, and the petroleum vapors are captured in drums of granulated charcoal, while the water is shunted off to a separate container.

Air injection/extraction system operating at W. Pacific Avenue gas station site in 2013 and 2014. System extracts and captures petroleum vapors.

The method of blowing bubbles in mud and sucking out the air sounds unsophisticated, but it works. After running the system in 2013 and 2014 at the West Pacific Avenue gas station site, for example, the level of one contaminant, benzene, went from around 1,000 micrograms per liter down to 58, bringing the contamination low enough to allow indigenous bacteria to finish the job.

Air injection and vapor extraction system operating at former commissary gas station site in May 2013. Charcoal tank to capture vapors is at left.

The Navy returned to these sites in July and, in this phase, they came to help natural bacteria finish up the job. Allowing bacteria to clean up petro chemicals through natural digestion is called bioremediation. To be effective and not take a century to eliminate the problem, the bulk of the chemicals need to first be reduced to concentrations that do not overwhelm the bacteria.

At both gas station sites the Navy used a special product designed to foster growth of natural bacteria in the ground, which includes a form of time-release peroxide that turns into oxygen over a period of 12 months. An oxygen environment is necessary for the bacteria to digest petroleum. The bacteria utilize the hydrocarbons (hydrogen and carbon) in the petroleum chemicals as part of their metabolic processes and convert them into carbon dioxide, water, and microbial cell mass. Water samples will be taken at three, six, and nine months after the July injections to evaluate effectiveness.

“The Navy’s gas station remedial program is comparable to the private sector gas station cleanup program,” said Yemia Hashimoto, Engineering Geologist with the San Francisco Bay Water Board. “The cleanup requirements are similar and the required timelines for project completion are similar.” The Water Board is a California state agency and is the lead regulatory agency overseeing the Navy’s petroleum cleanup program.

The other type of groundwater contamination encountered at Alameda Point comes from a chlorinated solvent used in cleaning aircraft parts. Unlike lighter-than-water petroleum products, chlorinated solvents can sink through the upper water zone to a depth of 30 feet or more and complicate cleanup. But solvent cleanup still relies on a phased cleanup approach, often employing bacteria in the final phase.

Originally published in the Alameda Sun.

Complete background and a detailed description of the cleanup process at the two gas station sites is in the Bioremediation Work Plan issued in July 2015.

Groundwater solvent cleanup will use cheese whey and veggie oil to feed natural bacteria

Cleanup Operating Unit 2B at east entry to proposed Town Center - Alameda Point. Graphics by Alameda Point Environmental Report. — Cleanup Operating Unit 2B at east entry to proposed Town Center – Alameda Point. Graphics by Alameda Point Environmental Report.

A Navy contractor will be cleaning up groundwater in part of the Town Center area next to the Seaplane Lagoon by injecting a solution of cheese whey, emulsified vegetable oil and water into nearly 200 wells that go down between 30 and 40 feet. The whey and vegetable oil will cause natural bacteria to flourish that will feed on the toxic trichloroethene (TCE) solvent causing it to break down.

According to the Navy, this type of food-stimulated bacterial bioremediation is common. The cheese whey is similar to the powdered whey products found in grocery stores. It will be delivered to the site already diluted in water. A hose will be connected to a fire hydrant and hooked to a metering device that will mix the whey and oil solution with municipal water as it is pumped into the wellheads.

The work is expected to begin in 2015, with periodic visits and testing until 2020. The first year of operation the contractor will make two visits of 35 days each. During each of these work periods they will inject 246,000 gallons of whey, oil, and water solution into the ground, allowing gravity to disperse the liquid.

The goal of the cleanup is to minimize the potential for hazardous vapors entering buildings, and chemicals migrating into the Seaplane Lagoon. TCE is an industrial solvent used to degrease metal parts. It was heavily used at aircraft and ship engine repair facilities on the site. A leak from a rail car is believed to be one of the major sources of the plume.

The 33-acre cleanup area is immediately to the south of the Navy jet on West Atlantic Avenue at the east entry to Alameda Point near Main Street. It is within the 150 acres of the Town Center that the city is seeking to develop in the near future. In April, the city council sent out requests seeking qualified developers interested in residential and commercial projects. The cheese and veggie oil cleanup area will not be transferred to the city until at least 2020 when cleanup has been certified to have met its goals.

Cleanup of fuel in groundwater ended about four years ago at an old fuel distribution point on the north side of the jet monument.

Below is an audio and image presentation from the Alameda Point Restoration Advisory Board meeting on May 8, 2014.

One of the high contamination "hot spots" that will get extra treatment to cleanup trichlorethene solvent in groundwater 30 to 40 feet deep. — One of the high contamination “hot spots” that will get extra treatment to cleanup trichloroethene solvent in groundwater 30 to 40 feet deep.

Fenced area is where testing was conducted. This is one of the hot spot areas that will get extra attention to clean up trichloroethene in groundwater.

Groundwater cleanup area on OU-2B. Cleanup will not be completed until 2020. Looking west with maritime ships in background in Seaplane Lagoon.

Fuel contamination in groundwater flagged for more cleanup work

Under the petroleum cleanup program the Navy has been removing tanks and fuel lines and cleaning up spills and fuel leaks dating back to the early 1990s before the base closed. Most of the tanks and fuel lines were removed within three years after the base closed in 1997.

Cleaning up leaked and spilled fuel has been slower, often involving running a vapor extraction pump 24/7 for years. In a few cases, a groundwater contamination site will require a callback after the initial work is completed. The Navy’s routine monitoring of groundwater, even after cleanup work has been completed, is aimed at determining whether there is a rebound in contamination readings and follow-up treatment is necessary. Three such sites needing more work, on land recently acquired by the city, are currently undergoing follow-up treatment at the Navy’s expense.

Two of the sites once served as automobile service stations. The other site is where fuel was removed from planes before they were serviced.

Former location of auto service station and car wash where fuel leaked into the ground. Part of the site is receiving follow-up cleanup work. Near Main St. and Pacific. Soccer field in background. — Former location of gasoline service station and car wash operated between 1971 and 1980 where fuel leaked into the ground. Part of the site is receiving follow-up cleanup work. Near intersection of Main St. and Pacific. Soccer field in background.

The treatment method is simple. Air is pumped into the ground where the contamination is the highest. This causes the petroleum products to vaporize, and then a suction system draws out the vapors into a barrel of charcoal. The air injected into the ground also helps natural petroleum-digesting bacteria to grow.

Petroleum cleanup site receiving follow-up cleanup next to Main St. across from Bayport. Site was former location of Navy auto service station.

Solar-powered cleanup for the first time at Alameda Point

Air injection/extraction pumps at the two former service station sites are running on electricity from the grid. At the former plane de-fueling site next to Building 410, however, the Navy is using a solar-powered pump for the first time anywhere at Alameda Point. Derek Robinson, the Navy’s Environmental Coordinator, explained the solar choice saying, “Electricity is not optimum because the overhead electrical tie-in is located too far away for the system to be tied in to the grid cost effectively. The solar units provide the power necessary to operate the air sparging and soil vapor extraction system at a competitive price.” The only other option was a combustion engine pump running on gas or diesel.

“The battery storage system is traditional lead/acid batteries,” said Robinson. “The solar array charges storage batteries allowing the system to store energy and operate in cloud cover and beyond strictly daylight hours; however, the system is designed to power off the blowers once the voltages drop below a preset level,” he said.

Sustainable Technologies, located just a block away at Alameda Point, constructed the entire rig. It consists of solar panels, a box full of lead-acid batteries, a circuit panel, and a pump. Ironically, Sustainable Technologies is located on a Superfund site that will take another six years to clean up.

The area next to Building 410 where the fuel spills occurred has had a number of cleanup actions going back to 2002. “Corrective actions under the petroleum program were conducted in 2002 and 2011 and a remedial action under the CERCLA [Superfund] program was conducted between 2005 and 2006,” said Robinson.

Work will continue until the end of the year. The Navy will always be responsible for returning to do more cleanup work if groundwater testing shows some of the contamination was missed.

Locations of three petroleum cleanup sites currently undergoing more cleanup work.

Cleanup at future Town Center – Alameda Point East Gate area

The city has announced that over 500 acres of land will be transferred from the Navy to the city on June 4, 2013. It will be the first – and largest – of a four-phase schedule of land transfers to the city. One of the areas that won’t be transferred this year is located at the main entryway into the future Town Center currently being designed.

OU-2B cleanup area — Illustrations on map by Richard Bangert. Click on map to enlarge.

Driving into the “East Gate” on West Atlantic Avenue to Ferry Point Road at the Seaplane Lagoon takes you through part of the future Town Center – and through a major environmental cleanup area called Operating Unit (OU) 2B.

Plans for a vibrant mixed-use Town Center to kick off redevelopment are now in the design stage, but 33 acres on the south side of West Atlantic Avenue won’t be transferred to the city until 2019. That’s when contaminated groundwater is expected to be cleaned up to commercial standards, allowing the Navy to turn over the land.

The overhaul of aircraft and ship engines in this area led to major contamination of groundwater with trichloroethane and vinyl chloride, as well as pockets of soil contamination. After testing various cleanup methods on the contaminated groundwater area – called a plume – the Navy and regulatory agencies have decided to rely mainly on bioremediation – natural bacteria – to degrade the contamination.

Soil hot spots will be removed, except under buildings. Future developers will be responsible for soil under buildings once they are demolished.

One of the groundwater hot spots close to the Seaplane Lagoon was successfully treated last year with a heat and vapor extraction system. Some of the other hot spots are impossible to treat with electrical heating because of underground power lines nearby.

UO-2B plume map w:photo overlay — Click on image to enlarge

The Navy has found bioremediation to be the most practical method to finish the job. Work details will be finalized later this year. Bioremediation can involve injecting new bacteria, but here it will likely mean injecting oxygen to spur the growth of existing bacteria. It’s the carbon atoms in the chemical contaminants that are attractive to bacteria, allowing them to naturally disassemble a chemical compound.

Someday, decades from now, the danger from vapors entering buildings will be low enough to permit ground floor residential use. Current restrictions imposed under the Navy’s cleanup plan will prohibit ground floor residential, but will allow residential use above the first floor, provided an approved vapor barrier and venting system is installed under any new construction. First floors will be allowed to have commercial uses once the city receives the land in 2019. Groundwater monitoring wells around the cleanup area will remain usable and accessible for regular monitoring for at least 20 years.

The cleanup area north of West Atlantic – 13 acres called Site 3 – will be turned over to the city next year following removal of several contaminated soil hot spots containing lead and other contaminants. Some of the contaminated soil areas are under building slabs on Site 3 and will be the responsibility of a future developer. All of the buildings in the East Gate cleanup area called Operating Unit (OU) 2B – 46 acres – are expected to be demolished rather than reused.

Site 3 north of West Atlantic was also heavily contaminated with jet fuel around an area where underground fuel storage tanks were once located. The former storage tank area is west of the jet monument and is still dotted with white pipe stubs once connected to a maze of cleanup pipes. The jet fuel cleanup was completed two years ago under the Navy’s Petroleum Program using a vapor extraction system. Removal of underground tanks and fuel lines was completed in 1999.

Vapor extraction system that operated for several years to clean up jet fuel in the ground on Site 3. Charcoal filter tank has been removed. Jet monument and Building 360 are in the background.

OU-2B looking east toward Bldg 360 — Click on image to enlarge.

Removing jet fuel line in OU-2B cleanup area in 1999. Jet monument is in background. Source: Navy environmental newsletter, Winter 1999.

Navy’s Proposed Cleanup Plan for OU-2B.

Navy could shut down groundwater treatment at housing site

The Navy often hears calls to increase its environmental cleanup effort. Now, the community and regulators are hearing a call from the Navy to eliminate one cleanup effort altogether.

North Housing area next to Island High School where benzene plume is located.

Since 2009, several acres of the area north of Bayport that includes the Shinsei Gardens affordable housing development, former Coast Guard and military housing, the closed Island High School, and the Woodstock Child Development Center have been undergoing groundwater treatment to eliminate hot spots of benzene and naphthalene vapors. Shinsei Gardens also included special building slab engineering in its design as an extra precaution against vapor intrusion. The Navy now says that its groundwater treatment system is unnecessary and should be shut down.

In a report issued in December 2012, the Navy said the underground vapor extraction system called biosparging is not making the area any safer for human habitation. Biosparging is a form of bioremediation that uses air and oxygen injections to stimulate the growth of naturally occurring bacteria, which break down toxics. In this case, the contamination is composed of waste material discharged from an Oakland coal gasification plant and an Alameda oil refinery that operated long before the area was filled in. The contamination layer has been dubbed the Marsh Crust.

The Navy’s report points to the initial studies in the area that showed no risk from vapors. The only justification for the remediation in the first place was the limited risk of contact with water through non-potable uses, since drinking water will always be supplied by East Bay Municipal Utility District.

Now the Navy says that even non-potable uses are impractical and off the table due to high levels of minerals such as salt. With no way of coming in contact with water containing benzene and naphthalene, the Navy decided to review the data for vapor exposure and concluded there is plenty of evidence to turn off the pumps. The biosparge system was designed to run for eight years in order to reach its cleanup goals.

Biosparging system for benzene and naphthalene vapors. White tanks are charcoal vapor filters.

Biosparge manifold for injecting oxygen.

The Navy’s December 2012 Technical Memorandum is seeking to amend the original cleanup decision — known as the Record of Decision (ROD) — for this cleanup area. They will need the concurrence of the regulatory agencies: the regional Water Board, state Department of Toxic Substances Control (DTSC), and the Environmental Protection Agency (EPA). But the EPA and DTSC are not ready to agree without further testing.

According to EPA’s Chris Lichens, “The Navy’s conclusions are not based on current data, site conditions, or investigation methods. Before proceeding with a ROD Amendment,” he said, “the agencies would like the Navy to collect additional data to verify that vapor intrusion would not present a significant risk in the absence of biosparging.” Lichens added, “Along those lines, EPA and DTSC jointly prepared recommendations for additional groundwater, soil vapor, and indoor air sampling and provided those recommendations to the Navy. The Navy has not yet agreed to collect additional data, although we are still discussing it with them,” he said.

Originally published in the Alameda Sun.

One of the groundwater treatment sites

North Housing. Benzene plume extends under lawn area, street, and housing in photo.

Ending threat of solvents in groundwater leaching into San Francisco Bay

Site 1 at the northwestern tip of Alameda Point was used as the principal disposal area for all waste generated at Naval Air Station-Alameda from 1943 to 1956. This disposal area, which was once part of the Bay, was created by sinking pontoons and barges in the Bay and backfilling with dredge soil.

Disposal of cleaning solvents and petroleum products at one unlined pit within the landfill resulted in a groundwater plume that poses a threat of leaching into San Francisco Bay today.

In the 1990s the Navy installed an underground barrier system, called a funnel and gate permeable reactive barrier, to stem the flow of contaminants into the Bay. It was not a permanent solution. In July of this year the permanent solution began with the injection of neutralizing chemicals into the plume.

Protecting marine life

San Francisco Bay at Alameda Point western shoreline where threat of solvent leaching exists.

Most cleanup activities around the base are aimed at eliminating direct health risks to humans, such as from soil or from vapors that could enter a building. In a few cases, the cleanup is focused first on direct impacts to marine life such as fish, which could in turn cause health problems for people who eat them.

The cleanup effort at the Site 1 plume is one of those cases. This effort will keep toxins — solvents, petroleum products, and metals — from ever leaching into the Bay, being ingested by fish, and then consumed by humans. The effort will also reduce unacceptable levels of vapors that are escaping directly above the plume. The future use of the site will be restricted to open space recreational.

The process

Manifold system for chemical injections — July 2012 – Manifold system of hose lines that send oxidant chemicals to individual wells that go into the underground plume contamination area. Navy photo.

The chemical injection process, called In Situ Chemical Oxidation (ISCO), is accomplished by injecting oxidants (catalyzed hydrogen-peroxide and sodium persulfate) into the plume through injection wells. “These oxidants produce short-lived reactions that directly destroy the targeted contaminants,” according to the Navy. Groundwater tests will determine if further treatments are necessary.

Tanks of chemicals for neutralizing solvent plume. Shown as work area being set up in June 2012.

Treatments will continue until either the groundwater is clean enough, or the solvent and petroleum concentration has been reduced by 75%. Once they get to 75% reduction, further injections are more or less a waste of money. From then on, the contaminant concentration is low enough that the remainder will either degrade or disperse and dilute naturally without posing a risk to fish or humans. This process is called natural attenuation and is often relied upon to finish the job when the bulk of contaminants are neutralized and treatment methods no longer yield effective results.

The groundwater plume is also contaminated with metals consisting of arsenic, copper, mercury, nickel, silver, and zinc. The metals problem will, in theory, be taken care of when the solvents and petroleum products are eliminated. This will cause the chemistry of the groundwater to change, which in turn will cause the metals to no longer remain dissolved in the water. The metals will return to their solid state and remain where they are. That’s the theory.

But to make sure it’s working, there will be a long-term groundwater monitoring program to make sure the metals aren’t moving. If problems arise in the future, the Navy will have to come back and design a new remedy. The Navy is responsible for the landfill’s contents staying in place in perpetuity.

Site 1 landfill groundwater treatment area — Map of Site 1 disposal area with arrow from left indicating plume treatment area. Map also shows outlines of individual unlined pits that were used for disposal of waste. Half of the area is now covered by runway.

The Navy opted not to remove the landfill contents because of the $93 million price tag and because the risk of contaminant releases was deemed low. A new set of environmental concerns associated with digging up and hauling away a landfill was also cited during the decision process.

The groundwater plume being treated is approximately 30 feet wide by 160 feet long, and it occurs mainly between depths of 5 and 10 feet below the ground surface.

Site 1 groundwater treatment work underway in July. San Francisco in background. Navy photo.

Delay on soil cover

All of 30-acre Site 1 will eventually be covered with soil and seeded with native grasses. Work on the soil cover was delayed when the contractor discovered that the part of the landfill once used for burning waste was larger than expected. The documentation has to go back through the review process, with a work plan for the soil cover hopefully prepared and ready to implement by 2014.

Groundwater cleanup back on track at heat treatment site

The groundwater remediation project between two buildings near the East Gate entrance, in the area known as Operating Unit 2B, finally got underway after a long delay in startup since last spring.

During set up, one of the 30-foot-long steel electrodes driven into the ground to generate heat struck a plastic sewer line. The sewer line was not on any maps and was undetectable through scanning since it is not iron. Operation of the system began last month after a sewer line bypass was installed, and it will continue through May.

OU-2B thermal treatment — Heating and extraction of solvents in groundwater between East Gate entrance and Seaplane Lagoon.

The contamination is from nearby aircraft maintenance operations that resulted in chlorinated solvents, used in cleaning aircraft parts, ending up deep underground in the groundwater. Of the three most common methods for cleaning up groundwater contaminated with solvents and fuels – pumping in neutralizing chemicals, heating up the ground to vaporize and extract the contamination, and bioremediation using microbes – the heat treatment method was chosen for this site because it is the fastest.

thermal treatment graphic — Graphic illustration of heat treatment system. Brown electrodes are heated with electricity, which heats the soil and groundwater, creating steam and toxic vapors that are sucked out into red pipe. Navy graphic.

It takes weeks for the ground to get to the target temperature of 194 degrees, which is the temperature at which the solvent boils and turns to vapor. Pipes at ground level suck the vapor out of the ground and channel it through a large pipe to the granulated activated carbon filter system.

Granulated activated carbon filter system in tanks. Water vapor and toxic vapors are captured and separated.

Other groundwater contamination nearby will be treated by a different method not yet announced. The Alameda Point electrical substation is near the other treatment area, and underground electrical lines leading every which way preclude the use of electrodes to heat the groundwater.