Bridgeton Landfill owner Republic Services is building a pipeline to carry wastewater from inside the landfill to a sewer line leading to the Bissell Point sewage treatment plant in north St. Louis.
The 7.5-mile-long pipeline will run along St. Charles Rock Road just south of Lambert-St. Louis International airport, through St. Ann and several other north St. Louis County communities.
That has some area residents worried about the potential for toxic contamination.
At a meeting on Monday night, the mayor of St. Ann and its Board of Aldermen spent close to 40 minutes questioning two Bridgeton Landfill representatives about the pipeline project.
Although more than two dozen members of the public attended, they weren’t allowed to ask questions.
St. Ann Alderwoman Amy Poelker, who requested the meeting, read a long list of concerns raised by her constituents. Their questions ranged from whether the wastewater ― or leachate, as it's known ― would be tested for radioactivity, to whether Republic Services would be responsible for any potential leaks.
Bridgeton Landfill Environmental Manager Brian Power said that the leachate has been tested for radioactive contamination on a quarterly basis for the past 10 years and has come up clean.
He also said the wastewater would be pretreated at the landfill to remove contaminants per Metropolitan St. Louis Sewer District requirements. “Before it’s ever discharged, it has to meet MSD permit discharge standards," Power said. "So the liquid that’s going into the pipeline is no different than any other industrial waste.”
Power said the landfill is covering all the costs of building the pipeline, which is expected to be completed by late January.
After that, the MSD will inspect it, then take over all responsibility for its operation and maintenance. "If anything was to happen, MSD would respond, and they would take appropriate action as they would with any other issue that they would have," Power said. "That’s the way that it’s worked out."
In other words, since the leachate pipeline will run into an existing sewer line, it will be treated like any other pipe in the MSD system.
Speaking after the meeting, St. Ann resident Doug Clemons said he was not reassured by what Power and his colleague had to say. He said he was concerned that without close oversight and testing by the MSD, the leachate in the pipeline could end up contaminated.
"One thing is radioactive waste materials, which are present in the groundwater underneath this landfill," Clemons said. "I find it hard to believe if they’re making their way to the groundwater, they’re not going to make their way to the leachate."
Clemons chairs the West Lake Landfill Community Action Group, which represents community members, workers and business owners to the U.S. Environmental Protection Agency concerning issues related to radioactive waste at the landfill.
Here’s a little background about wastewater at the Bridgeton and West Lake landfills:
What is leachate and how much does the Bridgeton Landfill produce?
Leachate is wastewater that builds up inside the landfill from the decomposition of waste. That wastewater also includes any rain that has soaked into the landfill and landfill gas condensate.
The Metropolitan St. Louis Sewer District currently receives all the leachate produced by the Bridgeton Landfill at one of two local sewage treatment plants, under conditions set by an agreement and discharge permit.
According to the MSD, it receives between 200,000 and 300,000 gallons of treated leachate a day from the Bridgeton Landfill, or 1.4 to 2.1 million gallons each week.
The subsurface fire that has been smoldering at the Bridgton Landfill since late 2010 has increased the volume of leachate produced there by about 50,000 gallons a day. It has also increased the concentration of certain contaminants such as benzene (see next section).
What is in the leachate at the Bridgeton Landfill?
Leachate contains toxic substances dissolved from the landfill waste or produced through chemical reactions inside the landfill.
Those can include heavy metals, volatile and semi-volatile organic compounds, ammonia, oil and grease.
As recently as March 2014, landfill owner Republic Services said that wastewater from the Bridgeton Landfill typically includes 1,000 to 1,500 µg/L (ppb) of benzene ― a known carcinogen.
In June 2013, the MSD stopped accepting leachate from the Bridgeton Landfill due to almost a year of permit violations related to "a significant increase in the discharge of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TSS)."
And the MSD later expressed concern that the leachate could be contaminated with dioxin, gross alpha radiation, gross beta radiation, gross gamma radiation (as cesium-137), radium-226 or radium-228.
In an email to St. Louis Public Radio, Russ Knocke, a spokesman for Republic Services, said that “leachate has been monitored under the permit with MSD for specific radiological components (uranium, thorium, radium, alpha, beta and gamma) even prior to initiating pretreatment at the site. Testing has always confirmed that these radiological components in leachate have been below permit limits, and that no treatment is necessary.”
The MSD confirmed this testing is required under Republic Services' current permit for wastewater discharge from the Bridgeton Landfill, (see section C.3, “radioactive discharge reporting requirements”). According to the permit, Republic Services can discharge up to the following amounts of radioactive materials per year: five curies of hydrogen-3; one curie of carbon-14, and one curie of all other radioactive materials combined.
What is Republic Services doing with the leachate from the Bridgeton Landfill?
Early in 2013, Republic Services began construction of a leachate pretreatment plant at the landfill, which began 24-hour operations in November of this year. The facility includes four, 1-million gallon storage and pretreatment tanks and a 316,000 gallon aeration tank.
Knocke described the pretreatment as a multi-step process “that has been developed to treat the leachate to meet the St. Louis Metropolitan Sewer District’s pretreatment requirements.” He said elements of the treatment include “aeration for volatile compounds, settlement of metals and solids, and bacterial digestion of organic compounds.”
Here are some more details from Knocke about the treatment process:
“Materials that are volatilized are treated through the leachate pretreatment plant’s thermal oxidizer units. Materials that are settled out of the leachate are pressed into a dry solid (with liquids going back into the treatment plant) and the solids are then profiled and disposed of as permitted. The treated leachate is then disposed of to wastewater treatment plants as approved under permits. All leachate is treated. Depending on plant operations, some leachate may not go through the full treatment plant and may be combined with treated leachate for disposal to MSD, in accordance with the MSD permit – meeting all MSD standards.”
Those standards are spelled out in Republic Services' permit for the Bridgeton Landfill on pp.2-5 and 12-13.
The MSD said that most of the treated leachate from the Bridgeton Landfill is currently being discharged to its Missouri Wastewater Treatment Facility, “via an existing pump station and force main which is mixed with other municipal sewage.” That leachate generally amounts to 100,000 to 300,000 gallons per day.
Treated leachate is also hauled via tanker truck to the MSD’s Bissell Point Water Treatment Facility “on an as needed basis.” The new sewer line discussed at Monday’s meeting in St. Ann is intended to eliminate the need for hauling leachate by truck from the Bridgeton Landfill.
What about leachate from the West Lake Landfill?
The West Lake Landfill is adjacent to, and just north of, the Bridgeton Landfill. It contains World War II-era uranium processing residues illegally dumped there in 1973.
The landfill is under the regulatory authority of the U.S. Environmental Protection as a Superfund site.
According to Republic Services, no leachate is collected or disposed of from the West Lake Landfill.
Follow Véronique LaCapra on Twitter: @KWMUScience