Learning to Live
A Report on OCWA’s Special June 2020 Webinar
PFAS in the Orange County
Occurrence, Regulation, and Impacts
on Local Water Supply
By Tim Hogan
Testing and tracing. Hallmarks of scientific inquiry, these twin pursuits formed the basis of the water industry’s initial response to the emerging issue of PFAS in local groundwaters.
PFAS, or perfluoroalkyl and polyfluoroalkyl substances, are a family of manmade compounds that have been in use since the 1940s. They were developed for their unique oil- and water-repellence, as well as resistance to degradation and surfactant properties. Over the years, they’ve been used in products ranging from cleaning compounds to firefighting foams, and found particular application as stain-resistant treatments for clothing and carpeting, as well as non-stick coatings for cookware.
Unfortunately, this widespread use led to widespread environmental contamination in soil, air, and water. And despite two individual “long-chain” PFAS — perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) — being phased out of production in the US and EU over concerns about their effects on human health, the very properties which made them useful — the strong carbon-fluorine bonds and their resistance to moisture and heat — render them hard to breakdown and remove, especially from water. For this, they’ve been dubbed “forever chemicals.”
Against this backdrop, Jason Dadakis, Executive Director, Water Quality & Technical Resources, Orange County Water District, joined OCWA for an informative, in-depth look at the issue of PFAS in the Orange County Groundwater Basin: Occurrence, Regulation, and Impacts on Local Water Supply.
As the inaugural presentation in OCWA’s Industry Insight On-Line Webinar Series, the Association could not have chosen a better speaker or a more engaging topic. And our membership and friends agreed, as 160 people signed up for the presentation, viewers from throughout Orange County, as well as sites as far flung as San Diego in the South to Humboldt Bay near the Oregon border.
After a quick overview of the situation, Dadakis looked back to March 2019, when the California State Department of Drinking Water (DDW) issued its initial PFAS monitoring orders. As the first public agency laboratory in California to be certified to analyze PFAS in drinking water, OCWD took the lead with its member agencies to both test their wells for contamination and, moreover, trace that contamination to its source.
Sample collection was conducted under strict guidance from DDW. To guard against cross-contamination, sample collectors were not allowed to carry pre-packaged food, fast food wrappers, or foil, nor were they allowed to use any notebooks, ink, or clothing that had been waterproofed. And while the sampling and test preparation was somewhat time consuming, taking between 2 to 3 weeks for analysis and reporting, through the utilization of automated extraction followed by liquid chromatography with mass spectrometry technology (LC-MS/MS), the District was able to ensure reliable, accurate PFAS detection.
Initial results showed only 9 local retail water agencies with one or more wells exceeding the State’s initial Interim Notification Levels (NLs). Additional research caused DDW to lower its Response Levels (RL) from 70 ng/L for combined PFOA + PFOS to 40 ng/L for PFOS and 10 ng/L for PFOA. These lowered RLs caused the initial analysis, where only 3 wells exceeded the combined RL, to blossom to 42 wells above the newer, lower RL. Furthermore, given that testing is expected to expand in light of these lowered numbers, OCWD projects that perhaps as many as 71 of its 200 service area wells could exceed the new RL. And with over 1/3 of its drinking water wells potentially out of commission, the District’s retail water systems could see a loss of some 100,000 acre-ft/yr.
The financial impact of this would be tremendous. To replace the output of these wells with costlier, imported surface water from Metropolitan Water District of Southern California (MWD) would cost some $30 million if only 42 wells are offline. This could rise to as much as $50 million if 71 wells are lost. And adding wellhead treatment for all these wells to the mix could bring the total to an excess of $850 million. Combined with the additional studies, testing, and treatment design activities OCWD foresees, total response costs could likely exceed $1 billion.
Fortunately, the tracing activities conducted in conjunction with the testing identified multiple potential sources for the PFAS release. These include local military bases, municipal airports, landfills, as well as discharges and runofrf to the Santa Ana River. Armed with this knowledge, true mitigation efforts become more realizable.
Fortunately, the testing regimens have produced positive outcomes as well. OCWD’s Groundwater Replenishment System potable reuse pronect has no detectable PFAS in its final product. Dadakis attributes this to the effectiveness of the Reverse Osmosis array (RO) used for GWRS water treatment. In addition, there is no detection of either PFOA or PFOS in any of the raw imported surface water purchased by the District for groundwater recharge from MWD.
To address this emerging issue, and provide leadership for its mitigation, OCWD has taken a strong stance. A PFAS Treatment Policy was adopted by the District’s Board in November 2019, then amended in February 2020. Among its objectives, the plan calls for OCWD to pay for 100% of capital expenditures needed for wellhead treatment, and up to 50% of Operations & Maintenance. To date, 9 of 10 affected Producers have signed onto the Agreement.
In addition, the District has selected Jacobs, a leading water and infrastructure engineering company, to review PFAS treatment remedies and support OCWD in the design of a pilot program. The pilot system, provided by Evoqua Water Technologies, will test Granular Activated Carbon (GAC), Ion Exchange (IX) Resin, and various novel adsorbents to develop a treatment regimen. These methods are being explored because, as Dadakis explained in the Q&A session after his presentation, while RO is shown to be extremely effective in removing all forms of PFAS, it is an expensive process with a problematic disposal/discharge issue to address.
Finally, OCWD selected Carollo, a leading water engineering firm, to assist with a regional planning study to evaluate how such treatment would be rapidly implemented. This effort will include assessing the number and locations of the wells impacted, the number of treatment systems required, their integration into the Producer’s operations, the necessary DDW permitting and California Environmental Quality Act (CEQA) assessments, along with capital cost estimates and initial designs. Already, the Wellhead Treatment System engineering designs are underway with a goal to bring them online within one to three years.
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