OSCODA – The preferred approach for reducing the per- and polyfluoroalkyl substances (PFAS) entering Van Etten Lake (VEL) in Oscoda was discussed during an Aug. 31 public meeting hosted by the Air Force Civil Engineer Center (AFCEC).
As part of the 30-day public comment period, those from the Air Force (AF) sought input on the proposed Interim Remedial Action (IRA) plan for VEL, at Ken Ratliff Memorial Park, to address the PFAS compounds perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). These and other PFAS are migrating into VEL from the former Wurtsmith Air Force Base (WAFB), via groundwater (GW), as a result of the aqueous film forming foam used at the site when it was an active base.
The remedial action alternatives that have been proposed are pump-and-treat by granular activated carbon (GAC), pump-and-treat by ion exchange or no action.
The reasoning for AFCEC’s preference being the GAC route was explained by Aerostar Senior Project Manager Paula Bond, as well as the Base Realignment and Closure (BRAC) Environmental Coordinator for AFCEC, Dr. Catharine Varley, who also serves on the Wurtsmith Restoration Advisory Board (RAB).
Participants could either attend the hybrid meeting in person at the Shoreline Players Community Theatre in Oscoda, or join virtually. It consisted of a technical presentation on the proposed plan, a question-and-answer session and a formal public comment period.
Answers were not given during the public comments; however, a court reporter was on hand to generate an official transcript and to capture oral remarks, which were to be included in the record.
For the technical presentation, Bond said she wanted to make sure everyone understands this is an interim remedial action. It’s not the final remedy for WAFB GW. “But again, an interim remedy to address some of those highest concentrations that we see moving toward Van Etten Lake.”
The preferred alternative, she said, will build on the success of the central treatment system (CTS) at WAFB, which was installed in 2018. And when that was built, it was done so with the ability to add capacity. “Which we are now doing with this IRA.
“Again, it is an interim remedial action, while the remedial investigation (RI) is ongoing,” Bond pointed out. And once the RI is complete, then a final remedy will be developed and presented in the feasibility study at that time.”
She gave a refresher on the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) process – which is being followed while moving through the IRA steps – to highlight where things stand currently.
The first was the IRA scoping between the AF and the Michigan Department of Environment, Great Lakes and Energy (EGLE). This was followed by the development of a remedial design, then development of the proposed plan.
“We’re in the 30-day comment period,” Bond said of the next step. Once this is over, they will develope a record of decision (ROD) for the interim remedy, after which will be a remedial action work plan. “And then that will be followed by the actual IRA itself.”
As for the area being looked at for the IRA, she said she wants to be clear that it doesn’t entail the entirety of VEL but, rather, is focused on Ken Ratliff Memorial Park. “It’s just the area at the park where the highest concentrations of PFOS and PFOA are moving toward Van Etten Lake.”
Among the slides she displayed was one showing the PFAS plume going into VEL, along with the proposed line of extraction wells that would be placed across the areas with the greatest PFOS/PFOA concentrations. This is where the GW would be removed, and anything that is falling behind that line will be captured in the extraction well system.
The plan shows the installation of 12 extraction wells, which will pump the GW back to the CTS. It will be treated through carbon vessels, discharged to the storm sewer and then eventually to Van Etten Creek.
Bond said that the new treatment system, or treatment train, for the proposed extraction well system will be installed on the other side of the existing CTS. The central plant currently pumps water from the Arrow Street and Benzene wells, and this water is also treated by GAC.
When it comes to the three IRA alternatives, she explained that considering the no action option is required under CERCLA, and is the baseline against which all other remedies are evaluated. For this, no actions are taken at all for the project, including monitoring, and the estimated cost is $0.
Hydraulic control using pump-and-treat with ion exchange resin, like the GAC method, would also call for the installation of 12 extraction wells. It would use ion exchange to treat the GW, and the system would be sized to treat 500 gallons per minute (gpm), which is the same as the existing CTS. This, too, would be installed on the other side of the CTS.
Bond said they would expand the footprint of the CTS to accommodate some additional treatment components, such as a filter press to remove water from solids and to reduce the overall waste moving off-site for disposal, from solids from the treatment system.
The existing GAC system would continue to operate in tandem with this new treatment train, and the estimated 30-year costs, including operation and maintenance (O&M), is $15.4 million.
The third alternative evaluated is hydraulic control using pump-and-treat with GAC, which would be sized to treat 500 gpm, as well. The estimated 30-year cost, including O&M, is $13.1 million. As with the ion option, the projected price includes capital costs, such as building construction and well installations.
Bond advised that each alternative was evaluated against nine National Oil and Hazardous Substances Pollution Contingency Plan (NCP) criteria. These are overall protectiveness of human health and the environment; compliance with Applicable or Relevant and Appropriate Requirements (ARARs); long-term effectiveness; reduction of toxicity, mobility or volume through treatment; short-term effectiveness; implementability; cost; support agency acceptance; and community acceptance.
She gave a quick overview of the summary of this evaluation. “No action, obviously, is not protective of human health and the environment,” she said, for instance. “So it gets a ‘no’ under that category.” But both the GAC and ion exchange resin alternatives do protect human health and the environment.
In another example, no action does not comply with ARARs. But pump-and-treat with both ion and GAC do comply.
With the exception of being easily implementable, the no action alternative doesn’t meet any of the other NCP criteria. “And then the other two alternatives do meet those other criteria,” Bond said.
She shared that after the alternatives were evaluated, the AF selected pump-and-treat with GAC as the preferred option. In addition to meeting the criteria, it is also more cost-effective than the ion exchange method.
Bond said that a building would be constructed to house the controls for the extraction wells, so that they can be easily sampled. It would also allow for easier monitoring of the efficiency of the wells.
This alternative would result in expanding the capacity of the CTS by 100 percent, increasing the treatment ability from 500 gpm to 1,000 gpm. “We would be installing equalization tanks, effluent tanks and settling tanks, similar to the system that’s already there,” Bond also said.
She noted that the current CTS is not pumping 500 gpm. “So there is a little bit of extra capacity left there, if we need to transfer from the new system over to the existing treatment train. So that is a safety factor that we’re using if we need to increase pumping rates for the new system.”
As for the comments received on the proposed plan – which could be shared during the meeting or sent to Varley by mail or e-mail – Bond said a written summary will be developed and included in a responsiveness summary in the interim ROD. The ROD will be created after the public meeting and the close of the public comment period which, as reported, was on Sept. 3.
Several people spoke during the question-and-answer session, including VEL resident Dick Haefner. Aside from the lower cost, he asked why the AF preferred the GAC alternative over ion.
Varley said that there is a good microbial population, which likes the ion exchange and adheres to it. “It excretes a polysaccharide like film over it, and causes it to be a lot less effective.” It also requires change-out much more frequently.
In reference to the extra capacity if there is a need to increase pumping rates, RAB Member David Winn asked for clarification. Based on the proposal, he said the 12 extraction wells will run at about 503 gallons, leaving the current system with an excess of approximately 180 gallons. “So if you’re really looking at it, there’s about 177 [gpm] excess in the current system. Am I correct in saying that?”
Project Engineer Jim Romer said that they have one shot at the infrastructure, in terms of size and piping, electrical and so on. When it comes to the modeling for instance, and in reference to recent a comment about higher VEL levels versus low lake levels, he explained that they looked at the hydraulic conductivities, “which is a number that basically characterizes the ability to transmit water through, in this case, sand.”
For this, there is data with a range of numbers, from about 81 feet per day to 145 or so. And he said the question becomes whether to model and design something for the best-case scenario, worst-case or the middle of the road.
“And so, the 503 number that you mentioned, we did the modeling with the higher hydraulic conductivity, put in a 15 percent engineering safety factor and so that number is now up to more like 591,” he told Winn. So they’re getting close to about 600 gpm and, while they won’t necessarily be operating at that, it is how they’re designing the size of the piping, the horsepower of the pumps and other items of that nature.
So, Romer continued, that’s almost 100 gallons (91 gpm) higher than what the second treatment train can run at total maximum. Therefore, with the 500 gpm, it’s like saying your car can run at 6,000 rpms and redline. “That’s not where you want to run it all the time. So I want to make sure we draw that distinction.”
As for the way this is being designed, he said there are uncertainties in terms of what they’re going to see, once it’s turned on. “That’s why we have performance monitoring and we’ll be looking at that.” So if they need to increase the flow in a well, based on empirical data collected, they want to have that capacity, too.
Romer said that when the main trunkline from the well control building comes into CTS, it will have a split in it. The operators will be able to divert probably 100 gpm or more, so that it can go through the existing 500 gpm in the CTS one treatment train.
He then mentioned a hypothetical mitigation scenario where there is coarser sand between two of the wells, water is coming through it quicker and the data shows that another well is needed. “But we are already designing into these trenches a spare water line conduit and everything else.”
So, if operationally they’ve been running for a while and they determine that they need to add another well, Romer says they want to have not only a blank conduit to bring that back to CTS, but they’ve got to have enough capacity for CTS to handle it.
He again stressed that theoretically, hydraulically they could tap out at 1,000 gpm. But, “Number one, you don’t want to operate at 1,000 [gpm].” And secondly, it gives zero room for flexibility in the event that more has to be pumped through the system.
“Isn’t that a diversion, as far as where you guys place the extraction wells and the distance between them?” Winn asked.
Romer said that what the team has done is start at the spacing that they’re running, which is about 250 feet apart. “And we knew that from that we could pump 20 [gpm] or we could pump 50. And we could effect a considerable amount of capture, depending on the conditions that we ran into.
“So this gets back to my point. Your observation is great in that, well, what if there is a negative impact to a different lake stage,” he continued. “And the answer to that is, I want to have the capacity to operate those pumps at a higher flow rate so I can accommodate that. And that’s the way we’re proceeding now.”
He added that modeling was conducted during both high and low lake levels, to make sure there would be enough capacity.
RAB Member and Need Our Water (NOW) Co-Lead Cathy Wuserbarth read several questions on behalf of a fellow NOW representative who could not attend the meeting. Among these, she stated that the AF does not present the other PFAS chemicals and plumes, and likely the central treatment plant’s influent will be a mix of these PFAS. The questions included whether carbon treatment is able to remove all of the contaminants and pollutants that will be entering the system, and if there will be illegal discharges of other PFAS, besides PFOS and PFOA, in the treatment effluent.
Varley said that they are looking at all of the different PFAS when designing the systems. Although they are primarily designing for PFOA/PFOS, they know that by capturing these, they also capture the rest.
Under the National Pollutant Discharge Elimination System, discharges of effluent must disclose all chemicals that may enter the surface water (SW), and must disclose the expected concentration of volume of such discharges, Wusterbarth also said, in reference to the other PFAS.
“We are following the law,” Varley assured.
Additionally, when comparing two of the alternatives, she noted that ion exchange is very specific. “It will only capture and only treat the PFAS compounds; whereas, GAC will treat also your co-contaminants that are coming into the system.”
The audience then heard from Eric Keller, who read a letter on behalf of U.S. Senator Gary Peters, and who shared that they would be supplying public comment to the VEL IRA, as well.
Except for a switch from the words “we” to “I,” the letter mirrored that which was also signed by, and included in a recent joint press release from, Peters (D-MI), U.S. Senator Debbie Stabenow (D-MI) and Congressman Dan Kildee (MI-05).
“As you are aware, the residents of Oscoda have been subjected to harmful [PFAS] in their [GW] and waterways – including at [VEL] – for many years,” the message, to Varley, reads in part. “While we acknowledge the Air Force’s work to initiate remediation and prepare the proposed IRA, it is insufficient to address PFAS contamination coming from Wurtsmith and abate the imminent and substantial threats to human health and the environment from PFAS contamination in the Van Etten Lake area.”
The politicians say multiple stakeholders have shared concerns that the AF plume maps and plans do not accurately represent how much contamination is entering VEL. Peters, Kildee and Stabenow urge the AF to work with the state of Michigan to ensure adequate testing and sampling.
“For example, the proposed IRA currently calls for 12 extraction wells across what is considered the worst plume entering [VEL], yet it only covers part of that plume versus the entirety of the plume in question,” their letter goes on. “While this should dramatically reduce the contaminants entering the southern end of the lake, contaminated areas around Wurtsmith will continue bleeding PFAS into the lake and thus lead to continued toxic surfactant foaming and attendant threats to human health.
“By choosing to focus on one part of one plume area in the proposed IRA, we are concerned that this and adjacent PFAS plumes will continue to spread unabated. We urge the [AF] to ensure the number, location, and length and depth of extraction wells accurately capture the entire PFAS contamination entering [VEL]. Doing so will help ensure that the continued imminent threats to human health, fish, wildlife, and the environment from PFAS contamination are addressed.”
They wrote that they wish to register their continued frustration at the AF’s unwillingness to utilize the SW discharge criteria established by the state of Michigan as an ARAR. “The [AF] has stated that the discharge system included in the proposed IRA ‘uses best available technology that produces a discharge with at or near non-detectable levels entering Van Etten Lake.’ As we noted in a previous letter sent this spring regarding the proposed IRA for Clark’s Marsh, rather than risk doing less now than what will ultimately be required, the [AF] should instead prioritize human health and meet Michigan’s state standards for addressing PFAS contamination from the start of the remediation process. This would also have the added benefit of preventing unnecessary expenditures of taxpayer money on enhancing treatment down the line.”
In light of the recently released Department of Defense(DoD) Inspector General report evaluating DoD’s use of PFAS at military sites around the country and the exposure of both military personnel and civilians living near such sites, Peters, Kildee and Stabenow said they were pleased to see that the AF engaged in a more transparent rollout surrounding the VEL proposed IRA than had occurred for the Clark’s Marsh IRA.
Varley told Keller that they have been undergoing an RI, and have collected a lot more data. “So I would love to share that with you afterwards, because I think there’s a misconception that we don’t understand.”
She added that they do understand what they’re doing in that area to capture the plume, and she would like to speak with Keller further, following the meeting.
Wusterbarth was among those to speak, when it came time for the formal public comment period. She shared that NOW had compiled its technical review of the proposed plan, and she proceeded to read their comments on same. The group also provided 12 technical comments, which Wusterbarth summarized.