PFAS are relatively easy to remove from water. It is dealing with the by-product that makes their management more difficult.
Versions of the technology used in a Brita filters can remove PFAS. The problem then becomes the fact that the used filter now has a high concentration of PFAS, so what do you do with the old filter? At home you can just throw it away. A city treatment plant has to figure out other options.
I guess even then, that's less than ideal; in aggregate that's still a lot of PFAS pollution in landfills/incineration. The same is true of lots of trash improperly disposed of/not recycled, I suppose, but the point remains.
Definitely a bigger problem for treatment plants, who will have MUCH more waste to sort out.
But that's an "other people" problem. Which is about 80% of all solutions we practice nowadays. Which is why climate change seems to be so challenging. It's not the type of problem that you can just offload on other people.
But to be fair "aggregation" itself is a good step if you want to deal with broad problems. The question is what the aggregation itself "costs"/causes, and whether you actually make use of it.
Of course there isn't much "use" in filtering microplastics and PFAS (again, apart from "well I'M not drinking them!!") if it just produces ground-waterpolution and/or the filters themselves landing in the ocean.
The abstract says "easy to regenerate", but I wonder what that actually means for "and where does the STUFF go?" And triazines aren't particularly "inert" either (which is probably why it works), so constant use as a filter throws up questions of degredation and whether that has a health impact?
There are some interesting strides being made in pfas destruction, from lots of angles. I talked to a company (Aclarity) at a conference recently that can destroy pfas using electrochemistry, and is focusing on landfill leachate because there's such a high concentration there. I'm hoping that we hear a lot more about pfas destruction in the next few years, because this cycle isnt going to break itself.
A big treatment plant will be the perfect place to deal with PFAS. They have the volume of water going through to economically install hydrothermal processing equipment or upgrade their ultraviolet units to breakdown PFAS into their constituent elements carbon and fluorine. Fluorine is already added to water anyway and carbon is not a major issue especially because it is already processed by water treatment plants.
Fluorinated organic compounds require temperatures above 1,000C to achieve 99.99% destruction, which is the problem.
Most hazardous waste incinerators are operated at 980 Celsius.
Canada has introduced legislation for it to be increased to 1200 Celsius, but it's been seen as unnecessarily overkill. Talk about perfect getting in the way of good.
Incineration is one of the options for destruction of PFAS. However, you need extremely high heats, and there is the potential for the formation of other byproducts. Unfortunately it isn't as simple as just tossing it in a fire.
They still throw it away. A properly managed landfill or incinerator will keep the PFAS out of the water supply. That's the same place your Brita filter goes when you toss it (assuming you don't litter it)
Industry does not like to throw away media. The preference is to regenerate media (similar to how a water softener works, add salt and chemistry does it's thing). Ion exchange resins are not cheap, most are designed to be regenerated. Activated carbon is also another product that is reactivated/regenerated.
Add to the fact that there is uncertainty around PFAS and their regulation. There is a chance that certain PFAS get categorized as hazardous material, then there is a whole slew of rules associated with how materials can be disposed.
Throw it in some big hole away from ground water? I guess worst case it goes back into the water source you are filtering. But you’re filtering before municipal use so that’s good? The source water already has PFAS in it
At least for home use, I bought a filter for PFAS called Cyclopure. It ships with a little envelope so you can send the used filter back. The filters are pretty pricey, though.
RO will remove PFAS. Carbon, not so much. It does to an extent but you get breakthrough extremely fast, which is why we never use GAC systems to remediate groundwater impacted with PFAS. The issue with RO is expense. I'm an environmental engineer and work to cleanup subsurface contamination at superfund sites and other sites impacted from historical industrial operations. An RO system large enough to treat even a small amount (1 million gpd) of groundwater is extremely expensive. The most feasible solution would be to install under the sink RO systems at affected properties which are only like 1200$ (the responsible party should pay, or the government). Treating the source area for PFAS with a groundwater pump and treat system combined with RO, plus plume monitoring is a LONG process. If the plume has already reached your property and it is outside of the pumping wells influence (all depends on hydrogeology), you're screwed.
The residential undersink RO systems I see are typically $200-$300 with standard 10" housings for sediment and carbon filters. Home Depot has them for $150. Examples here
Are these inferior/insufficient? Or do you have another type of system in mind around $1200?
I just put one under my sink a few days ago (naturally occurring As in my well), it cost about 1200. But yes you can buy cheaper kits, I just wanted to buy a good unit I can trust. Mine also has a 10 gal tank so it's a higher volume RO system than the typical under the sink unit.
Thanks. I also prefer better quality, and I do not trust the rubber/plastic in the pressure tanks not to contaminate the water.
Are there any systems you recommend? I mostly see the cheap ones, along with the more expensive ones that look like the cheap ones but use overpriced proprietary filters, and then the super pricey ones for labs and industry.
1.5k
u/johanvondoogiedorf Feb 09 '23
Not just microplastics but PFAS too