California Dreamin': A Suburb Offers Hope For Others Looking To Remove Toxins
California Dreamin': A Suburb Offers Hope For Others Looking To Remove Toxins
Novel Treatment Techniques Could Remove Long-Lasting Chemicals From Drinking Water.
Today, we’re putting the spotlight on Yorba Linda, California. It’s a suburban town in Orange County, California, about 35 miles south of Los Angeles.
This small, sunny city with less than 70,000 people has something that thousands of drinking water systems across the country will soon need—a per- and polyfluoroalkyl (PFAS) water treatment plant.
In fact, it’s the largest plant of its kind in the nation right now.
As a reminder: In April, the U.S EPA finalized new federal limits for six types of PFAS: PFOA, PFOS, GenX, PFBS, PFNA, and PFHxS, which means that public water systems have five years (by 2029) to implement solutions to reduce PFAS, if monitoring shows that drinking water levels exceed maximum contaminate levels or MCLs.
The EPA set MCLs of 4 parts per trillion (ppt) for PFOA and PFOS and 10 ppt for Gen X, PFNA and PFHxS.
PFAS chemicals are present in many products, including cosmetics, food packaging, water-resistant clothing, firefighting foams, and anti-stick coating for cookware. A recent study identified 57,000 sites contaminated by these chemicals in the U.S. alone.
Current estimates from the nonprofit org Environmental Working Group show that about 200 million people may be drinking water contaminated with PFAS. The EPA’s own assessment shows that about 60 million people get their water from a system containing PFOA or PFOS, two of the most well-studied PFAS, at maximum levels above the new proposed limits.
Yorba Linda is ahead of the game. I love seeing a quick and thoughtful response to a pressing problem.
In February 2020, the water district had to take all of its groundwater wells offline due to new state regulations of PFAS. Once the chemicals were detected, the district revved into action, partnering with the Orange County Water District to construct a new treatment plant.
The district researched and tested many technologies that could help remove PFOA and PFOS from the water and ultimately decided to build an Ion Exchange (IX) plant.
Ion exchange is a chemical process used to remove unwanted dissolved ions in water and wastewater. To remove the ions, they are exchanged with ions that have a similar charge.
The EPA recommends water treatment technologies such as ion exchange resins, activated carbon adsorption, and high-pressure membranes for the removal of PFAS.
The plant was completed in December 2021 with 6 pre-filter units, 22 Ion Exchange vessels, a 25 MGD booster pumping station, and a 1000 kW natural gas back-up generator. The plant distributes treated water to the community at an operating capacity of 19 million gallons of water per day.
“This December will be [three] years we’ve been running, and we’re the largest PFAS treatment plant using resin,” J. Wayne Miller, former board president at the Yorba Linda Water District, for whom the plant is named, told NPR.
The Yorba Linda PFAS treatment plant now stands over a long, narrow strip of the water district’s parking lot, a little less than the length of a football field.
Yorba Linda offers a model of success that I hope other cities will check out.
Testing Out Some New Material
A new filtration material developed by MIT researchers might provide a nature-based solution to water contamination issues.
The material, based on natural silk and cellulose, can remove a wide variety of persistent chemicals like PFAS, as well as heavy metals.
The findings are described in the journal ACS Nano, in a paper by MIT postdoc Yilin Zhang, professor of civil and environmental engineering Benedetto Marelli, and four others from MIT.
Contamination by PFAS and other compounds “is actually a very big deal, and current solutions may only partially resolve this problem very efficiently or economically,” Zhang said in a statement. “That’s why we came up with this protein and cellulose-based, fully natural solution.”
Zhang suggested that the new nanofibrillar material might be effective at filtering contaminants, but initial attempts with the silk nanofibrils alone didn’t work.
The team decided to try adding another material—cellulose. It’s abundantly available and easily obtained from agricultural wood pulp waste.
The researchers used a self-assembly method in which the silk fibroin protein is suspended in water and then templated into nanofibrils by inserting “seeds” of cellulose nanocrystals. This causes the previously disordered silk molecules to line up together along the seeds, forming the basis of a hybrid material with distinct new properties.
By integrating cellulose into the silk-based fibrils that could be formed into a thin membrane, and then tuning the electrical charge of the cellulose, the researchers produced a material that was highly effective at removing contaminants in lab tests.
The researchers found that the electrical charge of the cellulose also gave it strong antimicrobial properties, offering a significant advantage, since one of the primary causes of failure in filtration membranes is fouling by bacteria and fungi. The antimicrobial properties of this material are expected to greatly reduce that issue, according to the researchers.
“These materials can really compete with the current standard materials in water filtration when it comes to extracting metal ions and these emerging contaminants, and they can also outperform some of them currently,” Marelli said.
In lab tests, the materials were able to extract orders of magnitude more of the contaminants from water than the currently used standard materials, activated carbon or granular activated carbon.
The team plans to continue working on improving the material, especially in terms of durability and availability of source materials.
Initially, the material would likely be used as a point-of-use filter, something that could be attached to a kitchen faucet, Zhang described.
Eventually, it could be scaled up to provide filtration for municipal water supplies, but only after testing demonstrates it would not pose risk of introducing any contamination into the water supply. Both the silk and the cellulose constituents are considered food-grade substances, so contamination is unlikely.
“Most of the normal materials available today are focusing on one class of contaminants or solving single problems,” Zhang said. “I think we are among the first to address all of these simultaneously.”
More PFAS Research
The National Science and Technology Council, an executive branch body, published a five-year federal research and development agenda for understanding PFAS and guiding the government’s response.
The agenda identifies five focus areas including:
how people and the environment are exposed to the chemicals
how the chemicals are measured and monitored
the human and environmental health risks
technologies for removing and destroying the chemicals
alternatives to PFAS
Getting Pharma Out Of The Water
A new study reveals a novel water treatment process for removing trace pharmaceuticals from water.
The new innovation, developed by Carnegie Mellon researchers, shows promise as an effective, affordable, and versatile solution for getting rid of micro-pollutants in water.
The process involves a TAML catalyst and hydrogen peroxide, which effectively degrade several antibiotics and other drugs found in municipal secondary wastewater and contaminated river and lake water.
The drugs are representative of the hundreds of chemical micropollutants of concern found in wastewater throughout the world as well as in rivers and streams that supply drinking water.
“This work presents a low-cost, broadly applicable, safe and sustainable solution for purification of pharmaceutical-contaminated waters using an extremely low concentration of catalyst and peroxide,” said Terry Collins, the Teresa Heinz Professor of Green Chemistry and Director of the Institute for Green Science at Carnegie Mellon, in a statement.
The results, published in the journal ACS Sustainable Chemistry and Engineering, show that a next-generation TAML catalyst exhibits unprecedented efficacy in activating hydrogen peroxide at ultra-low concentrations.
The Carnegie Mellon investigators evaluated the ability of the next-gen TAML, called NewTAML, to degrade six high-concern drugs, four common antibiotics, a synthetic estrogen and a nonsteroidal anti-inflammatory drug, first in laboratory water spiked with the drugs, and then under more real-world conditions, including in spiked municipal secondary wastewater and water from rivers and a lake.
Many of the more than 4,000 prescription medications used for human and animal health ultimately find their way into the environment, according to the U.S. Geologic Survey.
In the last few decades, scientists have found a wide variety of pharmaceuticals in natural waterways. The drugs, which are excreted or flushed down the toilet because they are expired or unused, can slip through the purification processes at wastewater treatments plants and contaminate receiving waters.
Long-term exposure to these and another micropollutants can adversely affect, often severely, the health and behavior of wildlife, including insects, fish, birds and more.
Conventional wastewater treatment methods do not fully eliminate these micro-pollutants. And newer, advanced wastewater treatment processes, including ozonation and sorption onto activated carbon, are costly to implement and maintain, limiting their usefulness outside of large, wealthy cities.
Collins said he anticipates that the TAML/peroxide method can fill the gap.
“What’s now most exciting to me is that TAML/peroxide is so much easier to apply than anything out there,” Collins said. “All you need do is mix solutions of ultra-dilute TAML and very dilute peroxide into drug-contaminated waters and wait until the active pharmaceutical ingredients can no longer be detected. The full process takes from minutes to hours depending on how much TAML and peroxide you add, always at very low concentrations.”
The next step for researchers is to advance testing to the field.
Collins has patented the most advanced versions of the catalysts, and the intellectual property is licensed to Sudoc, a startup company working to bring TAML-based solutions to the market. Sudoc, Inc. recently raised $20 million in capital from various investors to, among other things, help launch its TAML/peroxide system into the European water treatment market.
What do you think of these new developments for getting PFAS and other contaminants out of the water? Let us know in the comments below!