Paving the Way to a Cleaner Environment by destroying PFAS.
Onvector’s mission is to break up a problematic molecule. That molecule can be any of hundreds of different types forming the wide variety of PFAS compounds.
Learn more about why it is important to destroy PFAS, where PFAS tends to accumulate, the technologies available to deal with it, and the role Onvector is playing in building a better world.
What’s so bad about PFAS?
Per- and polyfluoroalkyl substances (PFAS) are a class of manufactured chemicals that have been widely used in firefighting foam, breathable outerwear, degreasing compounds, as well as fast-food packaging and many other products. They’re a tremendously useful class of materials.
PFAS are often called “forever chemicals” because their molecules are persistent and will not easily break down. PFAS molecules include combinations of carbon and fluorine, which is one of the strongest chemical bonds known to science. This makes the foam able to survive the high temperatures of a fire without breaking down, so it can do its fire-suppression work.
But those same strong molecular bonds make PFAS difficult for the human body to clear once they are ingested. The fact that PFAS “bio-accumulate” in the body has put them in the regulatory cross-hairs of many environmental scientists, including some at the US Environmental Protection Agency. There is growing concern about health impacts, even at low concentrations measured in the parts per trillion range.
Regulators’ primary concerns are around two specific types of legacy PFAS — Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS) which were the most commonly used in AFFF and in consumer products. The EPA is considering listing them as hazardous substances under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA, also known as Superfund). This proposed rule would increase transparency around releases of these harmful chemicals and help to hold polluters accountable for cleaning up their contamination.
This designation would affect remediation efforts, notification requirements, and due diligence activities, and will have a ripple effect across many state regulations that reference CERCLA Hazardous Substances.
The EPA says that peer-reviewed studies have found that exposure to PFAS may lead to:
- Reproductive effects such as decreased fertility or increased high blood pressure in pregnant women
- Developmental effects or delays in children, including low birth weight, accelerated puberty, bone variations, or behavioral changes
- Increased risk of some cancers, including prostate, kidney, and testicular cancers.
- Reduced ability of the body’s immune system to fight infections, including reduced vaccine response
- Interference with the body’s natural hormones
- Increased cholesterol levels and/or risk of obesity
PFAS chemicals are typically impossible to destroy because they contain a molecular bond of carbon and fluorine, one of the strongest known to science. They’re called “forever” chemicals because they resist breaking down in nature.
- Now, forever doesn’t have to be forever. At Onvector, we’ve developed an innovative plasma vortex technology that uses the power of arc lightning to destroy PFAS molecules. You can take charge of your PFAS problem in a way that’s complete (final), energy efficient, and cost-effective.
Where are PFAS dangers located?
PFAS are widely used because of their many uses – in fact, some uses of PFAS are considered essential.
Firefighting impacts
The durability of PFAS molecules is one reason PFAS are such key ingredients in firefighting foams containing aqueous film-forming foam (AFFF, or “A-triple-F”).
For decades, AFFF has been a firefighter’s friend, prized for its abilities to spread rapidly across the surface of most hydrocarbon fuels, providing dramatic fire knockdown. AFFF has stopped a lot of fires, saved a lot of buildings, and protected a lot of lives.
There are three main areas in which PFAS is causing concern among the firefighting community: Employee health & safety, Current firefighting systems, and Impacts at fire-training sites
Landfills and leachate
As the preferred destination for trash, it’s to be expected that landfills will also become repository for many end-of-lifespan products (outerwear, non-stick cookware, mostly-empty lipstick tubes and many more) that contain PFAS.
As precipitation flows through the landfill, it picks up constituents along the way, including lead, mercury, pesticides … and PFAS. This “leachate” must be treated to remove those harmful constituents, before it can be released to surface water.
Many landfill operators solve this problem by pipelining or trucking their leachate to a nearby water treatment plant. However, this is becoming less practical for the treatment plants and their owners (in many cases, municipalities). This is because most treatment plants are designed deal with organic materials such as sewage; they’re not set up for industrial wastewater, or landfill leachate. Their treatment systems aren’t fully effective at removing PFAS from their effluent before it’s discharged. Owners are getting concerned about regulatory sanction, on their effluent and its leachate-derived PFAS, and increasingly are just saying “no” to landfill leachate.
Accordingly, more landfill operators are looking into ways to concentrate and isolate the PFAS in their leachate.
Brownfields
PFAS may also be present in the groundwater and soil of industrial sites. This is particularly properties where PFAS has been manufactured, products have been made that incorporate PFAS, or where PFAS has been used as part of a process – possibly degreasers and lubricants.
Hotspots of PFAS contamination may have occurred, and property owners may need to deal with those impacts before the land is sold.
Composting
With the trend to divert as much solid waste as possible away from landfills, many municipalities are encouraging organic waste be converted to compost, which can then be spread on municipal gardens or sold to the public. But one downside to this is that the organic waste often contains pizza boxes, fast-food wrappers and other materials that may contain PFAS. This spreads the PFAS further – particularly if that compost is used to produce food crops.
Wastewater sludge
Municipal and industrial water treatment often produces “sludge,” which is the solids left behind after the treatment process. This sludge often contains elevated levels of PFAS, sometimes because of the landfill leachate that passed through the plant. In some cases, the sludge is trucked right back to the landfill.
What are the current treatment technologies?
One of the issues in solving the PFAS puzzle is the sheer volume of water involved – and the expectations around the tolerances to be met.
This means that the emerging picture for PFAS removal is that of a two-stage process. The first is to reduce the scope of the problem by removing PFAS from the impacted water, and concentrating the PFAS-containing liquid to avolume that allows for effective treatment. The second is to destroy the PFAS molecules in that concentrate – to “mineralize” them, breaking them into constituent atoms or benign molecules.
PFAS concentration technologies
The following technologies are compatible with Onvector’s plasma vortex destruction technology:
Foam fractionation
This technology uses the surfactant qualities of PFAS, which make them so useful, to remove them from water. Foam fractionation involves releasing bubbles of air from below the water to be treated. The bubbles naturally move to the surface. On the way, the surface-active molecules, including PFAS, attach themselves to the gas-liquid interface of the bubbles, rising to form a foam on the liquid’s surface. This foam can then be skimmed off and isolated.
Ion exchange
This method uses ion exchange resins made of highly porous, polymeric material. The internal porous surfaces of the resins contain highly polar (charged) bound chemical groups that will attract molecules having opposite charge. PFAS molecules, holding a negative charge, are attracted to anionic exchange (positively charged) resins, from which they can be removed for treatment. Various forms of ion exchange are currently being tested.
Reverse osmosis
This involves using pumps to push the liquid up against a semi-permeable membrane. Water molecules are small enough to slip through the membrane, while larger contaminant particles and molecules – including PFAS – stay on the “concentrate” side of the barrier. While RO is used to treat landfill leachate, it has not yet been proven practical to work on impacted groundwater.
PFAS destruction technologies
Plasma
Onvector uses this technology destroys PFAS molecules by harnessing the fourth state of matter, plasma. Within the plasma vortex reactor, a voltage gradient is applied between two electrodes, through an external power supply. This creates an electric field that strips electrons from the inflowing gas molecules, creating charged ions and releasing a plasma discharge. The ions, which are charged particles, are highly chemically reactive, and are capable of breaking down PFAS molecules into. This breaks down PFAS into harmless byproducts like fluoride, sulfate, carbon dioxide and water. This is the process that Onvector uses.
Here are some of the methods for PFAS destruction that have been tried at bench and pilot scale; fewer have been developed to be ready for commercial use.
Supercritical water oxidation (SCWO, pronounced “Squo”)
Water above 705 °F and pressure of 221.1 bar is considered “supercritical,” a special state where chemical oxidation processes are accelerated. It may be that SCWO will prove a practical way to destroy PFAS by breaking the strong carbon-fluorine bonds and decomposing the material into a non-toxic waste stream. Like many technologies for destroying PFAS, it’s been shown to work – but the hard work will be showing that it can do this reliably and cost-effectively. SCWO is a tested and mature technology, but systems are expensive to build and have high energy utilization due to the required high temperatures. They are prone to corrosion and plugging when used for briny liquids, including PFAS concentrate streams. One variation on SCWO is hydrothermal alkaline treatment (HALT), which involves adding alkaline material to the PFAS concentrate. It involves lower temperatures and pressures than SCWO, but these systems have some of the same disadvantages as SCWO for PFAS destruction.
Electrochemical oxidation
This is a water treatment technology that uses electrical currents passed through a solution, such as PFAS-containing (-contaminated) water, to oxidize pollutants. Advantages of EC include: low energy costs, operation at ambient conditions, ability to be in a mobile unit, and no requirement for chemical oxidants as additives. Limitations of this technology include difficulty to scale-up to commercial volumes, the potential generation of toxic byproducts, incomplete destruction of some PFAS, efficiency losses due to mineral build up on the anode, the cost of electrodes, and potential volatilization of contaminants.
Incineration
One destruction technique that has been tried and found wanting is incineration – use of this method has found that not all PFAS molecules get destroyed, and/or harmful by-product molecules are formed. There is less use of incineration for PFAS destruction these days, because of this risk of simply spreading the problem up the stack and further afield.
Onvector’s plasma vortex technology is reliable, energy efficient and cost effective.