Pioneering Utility Shares Insights On PFAS Treatability

Source: Water Online

By Kevin Westerling,


Horsham Water & Sewer Authority, located just outside Philadelphia, was one of the earliest and hardest hit by PFAS contamination. Due to their experience, they are also among the best at treating to very low levels. Learn about the “Horsham Standard” and what drinking water utilities can expect as they endeavor to meet the pending national standard.

For most of the public, PFAS only showed up on their radar recently, as there has been a glut of mainstream news coverage about per- and polyfluorinated substances — PFOS, PFOA, GenX, and others — since the U.S. EPA proposed new federal regulations for maximum contaminant levels (MCLs) in drinking water. However, water utilities have been eyeing these “forever chemicals” for some time, especially in communities with especially high concentrations.

One such community was Horsham Township, PA, which is home to the Willow Grave Naval Air Station Joint Reserve Base (and also home base for Water Online). There, over the course of decades, the military’s use of PFAS-laden firefighting foam infiltrated and polluted the area’s groundwater. This put the Horsham Water & Sewer Authority, which relies on groundwater for its supply, on the front lines of the issue — long before this moment of national PFAS reckoning and regulations.

When it comes to PFAS, Horsham Water has been there and done that. More importantly, they did it well, proving that these chemicals aren’t ‘forever’, although getting there was no simple feat. As utilities across the country grapple with the pending regulations — a proposed 4-parts-per-trillion (ppt) limit on the two main PFAS, along with other mandates (more details here) — Horsham’s trials, travails, and ultimate success can help guide the way for others.

To that end, Water Online queried our neighbor, Tina M. O’Rourke, Business Manager at the Horsham Water & Sewer Authority, about the utility’s experience on what it took to conquer PFAS and ensure safe drinking water for those who live and work* in the township.

Given Horsham's experience with treating PFAS, what are your thoughts on the 4-ppt proposed limit for PFOA and PFOS that the U.S. EPA recently proposed?

The proposed MCLs by the EPA are essentially the current analytical detection levels for PFOA and PFOS in water which make it for all practical purposes the equal to Horsham Township’s adopted standard of “no-detect” for PFAS (dubbed “The Horsham Standard”). These proposed standards show the wisdom of the township’s/authority’s decision in establishing the standard and the approach necessary to achieve it both in the short and long term. This community had been exposed to very high levels of PFOA and PFOS in their drinking water for a long time before it was discovered and there was concern of the compounds bioaccumulating in the bodies. That the EPA now believes levels at 4 ppt are needed to protect the general population is certainly disconcerting and renews fears of the potential long-term health impacts to township residents from the legacy exposure. Completing ongoing epidemiological health studies needs to be a priority.

What challenges can utilities expect to face in terms of meeting these proposed regulations? What issues, if any, arose for you in the process?

At the time we were looking at PFAS treatment options, granular activated carbon (GAC) was the most accepted method in the limited research available. Knowing our water was contaminated with high levels — and having set the “Horsham Standard” — we had an urgency, and getting permits to pilot and then install treatment forced us to use GAC as that was where the regulatory agencies had the most comfort. Ion exchange (IX) was known to work but required extensive piloting, which we did, but it took four years to get a permit to utilize IX from the state regulatory agency because the agency deemed IX an “innovative technology’ for PFAS removal even though it has decades of use in water treatment systems across the U.S. for removal of nitrate, total organic carbon (TOC), and radiologicals. Although it was painstaking, we consider ourselves an integral part in paving the way for use of IX for PFAS removal, and as of this year, both Pennsylvania DEP and EPA are calling IX a “best available technology”, so utilities now facing the need to install PFAS removal treatment should not have the same difficulties in permitting that we experienced.

In Horsham's experience being out in front of this and an industry leader, how did you decide among the different technology options available for treatment?

With speed being the driver, GAC was really the only option we had in 2016. Now, based on our four years of IX piloting, as well as other utilities piloting, IX is now considered an equal to GAC for removal effectiveness and should be able to be permitted in the same time frame.

Who else within the workforce or municipality did you rely on for expertise and help in decision-making?

Certainly, the township council’s decision to adopt a “non-detect” standard for PFAS drove many of the decisions both in the short term and long term. HWSA’s engineering firm, Gilmore & Associates, Inc., was a major player through the piloting, permitting, and installation of PFAS treatment. Consultation with the state regulatory agency and with Calgon Corp. (GAC manufacturer) and Purolite (IX resin manufacturer) was crucial throughout the initial permitting process as well.

How did the Horsham team learn about the solutions that could help us solve the PFAS issue?

In 2016, there was little published on PFAS treatment options. Most of the available knowledge was based on DuPont’s work in cleaning up PFOA in West Virginia near their manufacturing facility. That experience pointed to GAC as the most accepted solution. Research on other options such as IX and even potentially RO [reverse osmosis] are much more readily available now.

Is there a hazardous byproduct to be disposed of after treatment? Where does it go, and are there issues (cost, safety, environment) to be addressed on that front?

There is a disposal dilemma for all treatment options. GAC and IX have the issue of the spent filter material to deal with, and RO has the issue of the permeate (10–20%) of the treated flow to dispose of in some manner. For the GAC and IX filter materials, the options are incineration (including GAC regeneration) or disposal in landfills. Research is ongoing on the best disposal options, and certainly this is an area where more information may better inform the decisions we are currently making. At this time, incineration (at extremely high temperatures) appears to be an adequate option for the destruction of PFAS, and we utilize this methodology to regenerate our spent GAC material for reuse. IX resin material cannot be regenerated, therefore the spent IX resin media is generally incinerated and/or landfilled. Thus far, we’ve only used minimal amounts of IX/resin media since it was only a small scale (albeit lengthy) pilot. However, we do have three full-scale IX treatment systems under construction at this time, which we hopefully will be able to place in service by the end of the year, and although the quantity of media required is far less than GAC, and media life greater than GAC, these will still generate PFAS-laden “residual” material. There are a limited number of facilities that will accept PFAS-laden materials, for either incineration or landfilling, given the current public aversion to anything PFAS, and the options are becoming fewer all the time. Hopefully the research will eventually help lessen the public’s fears and more options will become available in the future for disposal, because we are on a scary converging path of fewer and fewer facilities willing to accept PFAS-containing materials — and with the new standard, there will likely be many more treatment facilities coming on-line nationwide in the next few years.

*Thank you, Tina and Horsham Water!