~Lactose, veggie oil to stimulate toxic-eating bacteria
Cleanup of contaminated groundwater between Alameda Point’s Seaplane Lagoon and Main Street will begin later this year, according to the Navy. The cleanup area is directly south of the Site A residential and commercial parcel slated for groundbreaking in a few months. It is one of the most difficult environmental cleanup areas to remedy at Alameda Point, which is why it has taken 20 years to figure out what plan to implement. The Navy’s contractor presented the cleanup plan at the March 9, 2017 Restoration Advisory Board meeting at Alameda Point.
A cleaning solvent called trichloroethene was used in the Navy’s industrial repair and refurbishing operations in this area. The solvent leaked into the ground to depths of 70 feet and spread around nearly 19 acres. Industrial activities included the Aircraft Engine Test Facility in Building 360, which is the large building next to the Main Street soccer field, along with the Engine Test Cell in Building 14, and the Ship Fitting and Engine Repair Facility in Building 162.Continue reading “Toxic groundwater to be cleaned up using bacteria”
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.
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.
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.
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.
Navy environmental cleanup operations at Alameda Point ran the gamut during the summer and fall of 2014.
Operations included using bacteria to clean up groundwater, grinding radium out of a building floor, digging up lead-contaminated soil, constructing a metal shoreline waste barrier, digging up shoreline waste, preparing to install a 30-acre soil cover, constructing a new shoreline wetland, checking drain lines for contamination with cameras, and demolishing a several-acre temporary concrete drying pad near the old Control Tower.
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.