PFAS in a Nutshell

Posted April 13th, 2024

PFAS Basics.  The Significance of the EPA’s Recently Imposed Limits on PFAS Levels in Drinking Water

 Extracted from a Statement from Guardian Editor Georgia Warren

April 2024

With so many big, splashy headlines fighting for our attention every day, it’s easy to miss those vital stories that build drip by drip, slowly over many years.

Falling into that bucket this week was the news that the US government has imposed the first-ever limits on levels of PFAS in our drinking water. The Guardian has been aggressively covering the health threat posed by PFAS for years, including a year-long investigation with Consumer Reports that revealed the extent to which these so-called “forever chemicals” have permeated US drinking water supplies.

For those who haven’t been following this story, this acronym masks a dangerous issue that everyone with a human body should be aware of.

OK, so what are PFAS?
PFAS (short for per- and polyfluoroalkyl substances) are a group of about 15,000 human-made chemical compounds used widely in manufacturing to make products resistant to water, stains or heat – meaning they’re in everything from aerospace engineering components to takeout containers. Also known as “forever chemicals”, PFAS are unable to break down naturally in the environment or in our bodies.

Why should we care about them?
In recent years, scientists have discovered that exposure to PFAS is linked to a myriad of serious health problems, including cancer, obesity and birth defects. While many of the vast number of PFAS compounds remain unstudied, it is understood today that any exposure to some of the known highly toxic varieties is considered a health and cancer risk.

Are we all being exposed to these chemicals?
In short: yes – everywhere, all the time. In the past two months alone, the Guardian has published stories revealing that PFAS are entering our bodies via sources as disparate as bandagesartificial turfplastic sandwich baggies and household dust. However, our biggest exposure to PFAS is via our food and water – which takes us to this week’s big news.

What happened with PFAS this week?
On Wednesday, the US Environmental Protection Agency (EPA) announced legally enforceable drinking water limits for a group of the most dangerous PFAS compounds, after years of issuing only advisories. All US water providers will soon have to test their water and then install treatment systems that can filter PFAS if the results exceed EPA limits.

Is the PFAS problem solved then?
Public health advocates say it’s a great step – but not enough, as drinking water represents only about 20% of human PFAS exposure. Diet is likely a larger problem, as PFAS enter our food system via packaging, storage and machinery in factories, as well as during the farming process via contaminated water and sewage sludge used as fertilizer.

Is there hope for further action?
According to reporter Tom Perkins, who has been leading our PFAS coverage and provided this excellent analysis on the state of play following the EPA’s announcement this week: “Where there’s most hope is at the state level, where legislatures have started banning PFAS for all non-essential uses. It’s already happening in Maine and Minnesota. In turn, that creates market pressure on companies to stop using the chemicals altogether, because what are you going to do: produce shoes that can be sold in Mississippi but not in Maine? That wouldn’t make any sense.” Indeed, 3M, one of the world’s largest producers of the chemicals, announced last year that it would no longer make the compounds, citing in part the regulatory and legal environment.

That’s a lot of information: it seems the Guardian has really been on top of this issue.
Indeed. According to environment editor Mark Oliver: “In 2019, we launched a series called Toxic America, inspired by the idea that compared with the EU and other places, US safeguards and regulations around the threat of toxic chemicals were weaker. It’s one of those times where our outsider lens on the US can be helpful for how we see issues that perhaps other outlets aren’t seeing with as much alarm. We got a lot of engagement from readers on that series, and they helped us fund more journalism in that area. We’ve been in the vanguard of coverage around this ever since.”


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Biden Harris Administration Finalizes First-Ever National Drinking Water Standard To Protect 100M People From PFAS Pollution

Today, April 10, the Biden-Harris Administration issued the first-ever national, legally enforceable drinking water standard to protect communities from exposure to harmful per-and polyfluoroalkyl substances (PFAS), also known as ‘forever chemicals.’ Exposure to PFAS has been linked to deadly cancers, impacts to the liver and heart, and immune and developmental damage to infants and children. This final rule represents the most significant step to protect public health under EPA’s PFAS Strategic Roadmap. The final rule will reduce PFAS exposure for approximately 100 million people, prevent thousands of deaths, and reduce tens of thousands of serious illnesses. Today’s announcement complements President Biden’s government-wide action plan to combat PFAS pollution.

Through President Biden’s Investing in America agenda, EPA is also making unprecedented funding available to help ensure that all people have clean and safe water. In addition to today’s final rule, EPA is announcing nearly $1 billion in newly available funding through the Bipartisan Infrastructure Law to help states and territories implement PFAS testing and treatment at public water systems and to help owners of private wells address PFAS contamination. This is part of a $9 billion investment through the Bipartisan Infrastructure Law to help communities with drinking water impacted by PFAS and other emerging contaminants – the largest-ever investment in tackling PFAS pollution. An additional $12 billion is available through the Bipartisan Infrastructure Law for general drinking water improvements, including addressing emerging contaminants like PFAS.

EPA Administrator Michael Regan will join White House Council on Environmental Quality Chair Brenda Mallory to announce the final standard today at an event in Fayetteville, North Carolina. In 2017, area residents learned that the Cape Fear River, the drinking water source for 1 million people in the region, had been heavily contaminated with PFAS pollution from a nearby manufacturing facility. Today’s announcements will help protect communities like Fayetteville from further devastating impacts of PFAS.

“Drinking water contaminated with PFAS has plagued communities across this country for too long,” said EPA Administrator Michael S. Regan. “That is why President Biden has made tackling PFAS a top priority, investing historic resources to address these harmful chemicals and protect communities nationwide. Our PFAS Strategic Roadmap marshals the full breadth of EPA’s authority and resources to protect people from these harmful forever chemicals. Today, I am proud to finalize this critical piece of our Roadmap, and in doing so, save thousands of lives and help ensure our children grow up healthier.”

“President Biden believes that everyone deserves access to clean, safe drinking water, and he is delivering on that promise,” said Brenda Mallory, Chair of the White House Council on Environmental Quality. “The first national drinking water standards for PFAS marks a significant step towards delivering on the Biden-Harris Administration’s commitment to advancing environmental justice, protecting communities, and securing clean water for people across the country.”

“Under President Biden’s leadership, we are taking a whole-of-government approach to tackle PFAS pollution and ensure that all Americans have access to clean, safe drinking water. Today’s announcement by EPA complements these efforts and will help keep our communities safe from these toxic ‘forever chemicals,’” said Deputy Assistant to the President for the Cancer Moonshot, Dr. Danielle Carnival. “Coupled with the additional $1 billion investment from President Biden’s Investing in America agenda to help communities address PFAS pollution, the reductions in exposure to toxic substances delivered by EPA’s standards will further the Biden Cancer Moonshot goal of reducing the cancer death rate by at least half by 2047 and preventing more than four million cancer deaths — and stopping cancer before it starts by protecting communities from known risks associated with exposure to PFAS and other contaminants, including kidney and testicular cancers, and more.”

EPA is taking a signature step to protect public health by establishing legally enforceable levels for several PFAS known to occur individually and as mixtures in drinking water. This rule sets limits for five individual PFAS: PFOA, PFOS, PFNA, PFHxS, and HFPO-DA (also known as “GenX Chemicals”). The rule also sets a limit for mixtures of any two or more of four PFAS: PFNA, PFHxS, PFBS, and “GenX chemicals.” By reducing exposure to PFAS, this final rule will prevent thousands of premature deaths, tens of thousands of serious illnesses, including certain cancers and liver and heart impacts in adults, and immune and developmental impacts to infants and children.

This final rule advances President Biden’s commitment to ending cancer as we know it as part of the Biden Cancer Moonshot, to ensuring that all Americans have access to clean, safe, drinking water, and to furthering the Biden-Harris Administration’s commitment to environmental justice by protecting communities that are most exposed to toxic chemicals.

EPA estimates that between about 6% and 10% of the 66,000 public drinking water systems subject to this rule may have to take action to reduce PFAS to meet these new standards. All public water systems have three years to complete their initial monitoring for these chemicals. They must inform the public of the level of PFAS measured in their drinking water. Where PFAS is found at levels that exceed these standards, systems must implement solutions to reduce PFAS in their drinking water within five years.

The new limits in this rule are achievable using a range of available technologies and approaches including granular activated carbon, reverse osmosis, and ion exchange systems. For example, the Cape Fear Public Utility Authority, serving Wilmington, NC – one of the communities most heavily impacted by PFAS contamination – has effectively deployed a granular activated carbon system to remove PFAS regulated by this rule. Drinking water systems will have flexibility to determine the best solution for their community.

EPA will be working closely with state co-regulators in supporting water systems and local officials to implement this rule. In the coming weeks, EPA will host a series of webinars to provide information to the public, communities, and water utilities about the final PFAS drinking water regulation. To learn more about the webinars, please visit EPA’s PFAS drinking water regulation webpage. EPA has also published a toolkit of communications resources to help drinking water systems and community leaders educate the public about PFAS, where they come from, their health risks, how to reduce exposure, and about this rule.

“We are thankful that Administrator Regan and the Biden Administration are taking this action to protect drinking water in North Carolina and across the country,” said North Carolina Governor Roy Cooper. “We asked for this because we know science-based standards for PFAS and other compounds are desperately needed.”

“For decades, the American people have been exposed to the family of incredibly toxic ‘forever chemicals’ known as PFAS with no protection from their government. Those chemicals now contaminate virtually all Americans from birth. That’s because for generations, PFAS chemicals slid off of every federal environmental law like a fried egg off a Teflon pan — until Joe Biden came along,” said Environmental Working Group President and Co-Founder Ken Cook. “We commend EPA Administrator Michael Regan for his tireless leadership to make this decision a reality, and CEQ Chair Brenda Mallory for making sure PFAS is tackled with the ‘whole of government’ approach President Biden promised. There is much work yet to be done to end PFAS pollution. The fact that the EPA has adopted the very strong policy announced today should give everyone confidence that the Biden administration will stay the course and keep the president’s promises, until the American people are protected, at long last, from the scourge of PFAS pollution.”

“We learned about GenX and other PFAS in our tap water six years ago. I raised my children on this water and watched loved ones suffer from rare or recurrent cancers. No one should ever worry if their tap water will make them sick or give them cancer. I’m grateful the Biden EPA heard our pleas and kept its promise to the American people. We will keep fighting until all exposures to PFAS end and the chemical companies responsible for business-related human rights abuses are held fully accountable,” said Emily Donovan, co-founder of Clean Cape Fear.

More details about funding to address PFAS in Drinking Water

Through the Bipartisan Infrastructure Law, EPA is making an unprecedented $21 billion available to strengthen our nation’s drinking water systems, including by addressing PFAS contamination. Of that, $9 billion is specifically for tackling PFAS and emerging contaminants. The financing programs delivering this funding are part of President Biden’s Justice40 Initiative, which set the goal that 40% of the overall benefits of certain federal investments flow to disadvantaged communities that have been historically marginalized by underinvestment and overburdened by pollution.

Additionally, EPA has a nationwide Water Technical Assistance program to help small, rural, and disadvantaged communities access federal resources by working directly with water systems to identify challenges like PFAS; develop plans; build technical, managerial, and financial capacity; and apply for water infrastructure funding. Learn more about EPA’s Water Technical Assistance programs.

More details about the final PFAS drinking water standards:

  • For PFOA and PFOS, EPA is setting a Maximum Contaminant Level Goal, a non-enforceable health-based goal, at zero. This reflects the latest science showing that there is no level of exposure to these contaminants without risk of health impacts, including certain cancers.
  • EPA is setting enforceable Maximum Contaminant Levels at 4.0 parts per trillion for PFOA and PFOS, individually. This standard will reduce exposure from these PFAS in our drinking water to the lowest levels that are feasible for effective implementation.
  • For PFNA, PFHxS, and “GenX Chemicals,” EPA is setting the MCLGs and MCLs at 10 parts per trillion.
  • Because PFAS can often be found together in mixtures, and research shows these mixtures may have combined health impacts, EPA is also setting a limit for any mixture of two or more of the following PFAS: PFNA, PFHxS, PFBS, and “GenX Chemicals.”

EPA is issuing this rule after reviewing extensive research and science on how PFAS affects public health, while engaging with the water sector and with state regulators to ensure effective implementation. EPA also considered 120,000 comments on the proposed rule from a wide variety of stakeholders.


PFAS, also known as ‘forever chemicals,’ are prevalent in the environment. PFAS are a category of chemicals used since the 1940s to repel oil and water and resist heat, which makes them useful in everyday products such as nonstick cookware, stain resistant clothing, and firefighting foam. The science is clear that exposure to certain PFAS over a long period of time can cause cancer and other illnesses.  In addition, PFAS exposure during critical life stages such as pregnancy or early childhood can also result in adverse health impacts.

Across the country, PFAS contamination is impacting millions of people’s health and wellbeing. People can be exposed to PFAS through drinking water or food contaminated with PFAS, by coming into contact with products that contain PFAS, or through workplace exposures in certain industries.

Since EPA Administrator Michael S. Regan announced the PFAS Strategic Roadmap in October 2021, EPA has taken action – within the Biden-Harris Administration’s whole-of-government approach – by advancing science and following the law to safeguard public health, protect the environment, and hold polluters accountable. The actions described in the PFAS Strategic Roadmap each represent important and meaningful steps to protect communities from PFAS contamination. Cumulatively, these actions will build upon one another and lead to more enduring and protective solutions. In December 2023, the EPA released its second annual report on PFAS progress. The report highlights significant accomplishments achieved under the EPA’s PFAS Strategic Roadmap.

Source: U.S. EPA

PFAS in Prison Water

Posted April 8th, 2024

Nearly half of US prisons draw water likely contaminated with toxic PFAS

Around 1m people, including 13,000 youths, especially vulnerable because they can do little to protect themselves

Nearly half of US prisons draw water from sources likely contaminated with toxic PFAS “forever chemicals”, new research finds.

At least around 1m people incarcerated in the US, including 13,000 juveniles, are estimated to be housed in the prisons, and they are especially vulnerable to the dangerous chemicals because there is little they can do to protect themselves, said Nicholas Shapiro, a study co-author at the University of California in Los Angeles.

“We need to think about who is exposed and who has the least agency to mitigate their exposure – that’s why this is such a unique population,” he said. “We see the dehumanization of incarcerated people across the country, and these exposures are symptoms of that larger problem.”

PFAS, or per- and polyfluoroalkyl substances, are a class of about 15,000 chemicals often used to make products resistant to water, stains and heat. They are called “forever chemicals” because they do not naturally break down, and are linked to cancer, liver problems, thyroid issues, birth defects, kidney disease, decreased immunity and other serious health problems.

The study analyzed the likelihood that watersheds serving the nation’s 6,118 carceral facilities were contaminated with PFAS. The authors zoomed in on hydrologic unit codes to identify those regions near prisons most likely to be contaminated from nearby airports, military sites, landfills, wastewater treatment plants and a range of manufacturing facilities.

The study found that testing has only been performed on several hundred of the drinking water sources identified, and better monitoring is “desperately needed”, the authors wrote. The true number of incarcerated people drinking contaminated water is likely much higher, they noted.

Shapiro highlighted a women’s prison near Tampa, Florida, that draws from groundwater highly contaminated by PFAS-laden firefighting foam from by a nearby firefighting school. Foam is one of the largest sources of PFAS water pollution in the US.

Levels in the groundwater were 170 times higher than state health guidelines, and officials warned residents who drew the water – but no one alerted the incarcerated people or did anything to prevent their exposure. Even when incarcerated people learned of the threat, the state would not provide clean water.

That is especially a problem because the nation’s prison population is generally in poorer health than the non-incarcerated population, and the issue disproportionately threatens people of color and people with lower incomes, Shapiro noted.

“For all of these reasons, we need to take extra care to understand these exposures and mitigate them,” he said.

Source: The Guardian

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Posted March 20th, 2024

Why We Send Postcard Reminders


If you have a product of ours that requires regular replacement parts, we send you a postcard reminder once a year. Reminders go to customers who need filter cartridges for whole house or drinking water filters or reverse osmosis units, washing machine or garden hose filters. Even shower filters.  UV customers also get cards to remind them to replace the ultraviolet lamp.

Cards are sent with the broad assumption that cartridges and lamps need to be replaced once a year. It’s an imperfect system, and once a year is as close as we can get. We fully realize that in some homes one person uses the shower filter while in others six do.   People often tell us things like the filter is in a summer home that is unoccupied much of the year, or that their daughter has gone away to college, so they don’t need replacements as often. That’s way too complicated for us. We are simple people and it’s a simple system.  Once a year. And it’s once a year from your last purchase: If we send a card in February and you purchase in April, you’ll get your next reminder in April. And if you don’t purchase, you don’t get another postcard.

And if you get a card and don’t buy anything, you won’t get another card until you buy something, so rest assured that buying a countertop water filter from us does not put you on a never-ending mailing list. We aren’t like the Vet who’ll keep sending cards until you take Bowser in for his rabies shot.

Postcards may be the most popular thing we do, judging from the many thank-you notes we get. Cards make re-ordering easy. They tell you what you need to know to order by phone or from our website.

Why don’t we send email reminders instead? Email is cheaper and easier. We’ve tried, and email isn’t even remotely as effective as a postcard.


Do KDF Filters Remove Chloramine from Water?

Contrary to popular legends, KDF 55 and KDF 85 do not remove chloramine from water. In filters where KDF is mixed with carbon, there may be some chloramine reduction, but the KDF has nothing to do with it.


 Rainwater Everywhere Contains Unsafe Levels Of PFAS

By Peter Chawaga


Drinking water and wastewater managers throughout the U.S. are keenly aware of just how pervasive per- and polyfluoroalkyl substances (PFAS) can be in the environment. But now, new research has found that all rainwater around the world contains these contaminants to unsafe degrees.

“Atmospheric levels of toxic ‘forever chemicals’ are so high that rainwater everywhere contains amounts that are unsafe for long-term human consumption according to safety guidelines,” Vice reported. “‘Even in these remote and sparsely populated regions, such as Antarctica and the Tibetan plateau, the most stringent PFAS guidelines are exceeded,’ according to a study.”

The rising prevalence of PFAS in drinking water around the country has prompted the U.S. EPA to commit to more stringent regulations around the contaminants, has initiated a “seismic shift” in the legal landscape for industrial polluters, and has prompted existential questions about how drinking water and wastewater operations are supposed to respond.

But this latest study underscored the fact that PFAS are nearly impossible to avoid, no matter what actions water and wastewater systems take.

“This new study, which looks at four specific chemicals in the class, suggests that levels of one PFAS in rainwater around the globe often ‘greatly exceed’ US drinking water advisory levels,” according to the BBC. “The study’s findings lead the authors to conclude that a planetary boundary has been crossed — that there simply is no safe space on Earth to avoid these substances.”

As researchers learn more about PFAS and the potential harm that can come from exposure to them, regulations are becoming stricter. And while the production of products containing PFAS has been largely phased out, these so-called forever chemicals remain in the environment for a notoriously long time.

With the global environment now found to be totally inundated with PFAS, much of the burden for keeping these compounds away from consumers continues to fall on drinking water treatment operations.

“Removing the chemicals in the study from drinking water at treatment plants is possible, if expensive,” per BBC. “But getting below the US advisory levels is extremely challenging, according to the authors.”

Water Online


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Ultrapure Water Is Not For Drinking


While we think that water straight from the RO unit is wonderful, water can indeed by too pure for human consumption.

What is commonly referred to as “ultrapure” water goes beyond what is considered pure drinking water. In fact, it is not considered “fit” for human consumption. It is water so clean that it is used as an industrial solvent for cleaning semiconductors, producing pharmaceutical products, and for cooling in power plants.
Typical production of ultrapure water includes use of microfiltration membranes to remove particles from the water, ion exchange and reverse osmosis (RO) membranes to remove ions, UV light to kill bacteria and degassing membranes to remove dissolved oxygen.
We think of reverse osmosis, which can turn sea water into excellent drinking water, as taking “everything” out of water, but when it comes to water needed for many technical processes RO water isn’t even nearly clean enough. Ultrapure water requires 12 filtration steps beyond RO with the final filter having pores 20 nanometers in width.  (Twenty nanometers is 0.02 microns.)


Posted February 21st, 2024


Scientific developments like  membrane bioreactor technology enable enduring, sustainable development that does not leave permanent scars on the planet.  — Shivali Vora.

Countries all over the world are facing progressively higher levels of water stress — periods when demand exceeds supply. Part of the issue is that demand exists not just for drinking water, but also for water used for agriculture, livestock and electricity generation. From hydropower to nuclear power plants, many forms of energy, renewable and nonrenewable alike, require large volumes of water, as does irrigation for staple crops like sugarcane, wheat and rice, all of which are in high demand as the world population rises relentlessly.

Singapore has one of the highest gross domestic product (GDP) per capita in the world, but it is also one of the most water-stressed nations in the world because of limited land for reservoir construction, few freshwater resources, increasingly common droughts and climbing average temperatures. However, their extensive water reclamation system is alleviating some of the stress and making a heavily limited resource last longer for this island state.

To achieve the goal of water self-sufficiency and independence from foreign imports, Singapore began researching and, in 1998, building a system of 17 reservoirs connected by water reclamation plants — facilities that clean wastewater and in some cases recover the extracted materials for reentry into the ecosystem. Decades of investment into research and development for superior wastewater treatment have resulted in a product called NEWater that is well within World Health Organization (WHO) potability standards. The wastewater first goes through a filter that removes debris and pollutants, followed by passage through a membrane bioreactor, which efficiently combines bioreactors (growing specific biomass that will chemically consume unwanted substances in wastewater) with microfiltration or ultrafiltration. After this, a round of reverse osmosis — the process of using pressure to force water through a semipermeable membrane, thereby separating it from possible contaminants — targets microorganisms, metals, hydrocarbons, pesticides and other impurities. Finally, disinfection with UV light kills any remaining traces.

Most of the end product is used industrially, such as for microchip manufacturing, but small amounts are also added to drinking water reservoirs, especially after periods of evaporation. Singapore now uses NEWater to meet 40% of its water needs, as it is significantly cheaper than desalination. Its success and public acceptance are in large part due to successful collaboration between the scientists who developed it and the community leaders who spread awareness about it. At National Day Parades, for example, bottled NEWater was distributed for people to taste. Engagement and transparency with both the public and partnering sectors like the semiconductor industry — now a significant consumer of NEWater — helped the science make it from the lab to Singapore’s future.

Singapore’s resourcefulness and commitment to water recycling is quite uncommon; 80% of wastewater worldwide flows back into the ecosystem unmanaged. For emerging economies like those in sub-Saharan Africa, where only 30% of people have reliable access to a safe supply of water on tap, adopting Singapore’s innovative technology may help build sustainable water security. Despite the initial burden of financing the design and implementation of a water reclamation system, it will pay off in multitudes.

Ultimately, economic development rests on the shoulders of basic needs like food, water and energy. Pushing toward indiscriminate urbanization and industrialization does no good if long-term sustainability is not adequately considered in parallel, instead of as an afterthought — as evidenced by post-Industrial Revolution development, which left irreversible environmental destruction in its wake. Furthermore, the onus of these efforts falls on wealthier countries, which have the means to finance solutions to this destruction.

Excerpted from “From Field to Future: Wastewater Treatment and the Path to Water Security,” by Shivali Vora.  La Hoya, February 16, 2024.

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Adsorption of Water Contaminants: How Filter Carbon Works

According to the Wikipedia,  “Adsorption is the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved solid to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. This process differs from absorption, in which a fluid (the absorbate) permeates or is dissolved by a liquid or solid (the absorbent). Note that adsorption is a surface-based process while absorption involves the whole volume of the material.”

Explained more graphically:



This man has adsorbed a pie.



This man is absorbing a pie.

In water treatment, activated carbon is the main adsorbing agent. This is true because filter carbon has an amazing amount of surface area and a strong ability to attract and hold organic chemicals.

Most of the surface area of a particle of carbon is internal.

Enlargement of granular carbon shows countless pores that adsorb contaminants. The surface area of the pores is exceptional. A single pound of activated carbon has more surface area in its pores than 100 football fields.

Carbon’s amazing ability to adsorb organic chemicals varies according to the chemical in question and conditions of the water. In general, chemicals of high molecular weight and low solubility are most easily adsorbed. The lower the concentration of the chemical, the higher the adsorption rate by carbon. Also, the fewer the interfering organic compounds present in the water the better. The pH of the water is also significant, with acidic compounds being most readily adsorbed at low pH. And, as with most other aspects of water filtration, rate of flow of the water being treated is extremely important with carbon adsorption. The more residence time the better.

In regard to specific chemicals, one source lists dozens of common chemicals and ranks them according to the likelihood that they will be removed by carbon adsorption. Here are a few of the more common items from the list:

Very High Probability of Adsorption: Atrazine, Malathion, 1, 3-dichlorobenzene,  DDT, Lindane.

High Probability of Adsorption: Toluene, styrene, benzene, carbon tetrachloride, vinyl acetate,  phenol.

Moderate Probability of Adsorption: Chloroform, vinyl chloride, acetic acid.

Unlikely to be adsorbed by carbon:  Isopropyl alcohol, dimethylformaldehyde, propylene.

It should be remembered that although carbon has great chemical reduction capacity because of its ability to attract and hold chemicals on its surface, it acts in other ways as well. Chlorine, for example, is reduced mainly by catalytic reaction with the carbon, not by the “grab and hold” process of adsorption.

Despite Regulatory Push, U.S. EPA Finds Nutrient Pollution Isn’t Improving

By Peter Chawaga


Despite notable efforts from industrial wastewater operations and treatment utilities alike, the U.S. EPA has seen virtually no progress on one of the country’s most pressing contamination problems.

“The nation’s rivers and streams remain stubbornly polluted with nutrients that contaminate drinking water and fuel a gigantic dead zone for aquatic life in the Gulf of Mexico,” the Associated Press reported. “It’s a problem only expected to get harder to control as climate change produces more intense storms that dump rain on the Midwest and South. Those heavy rains flood farm fields, pick up fertilizers and carry them into nearby rivers.”

The troubling results were uncovered by an EPA assessment of samples collected in 2018 and 2019, comparing river conditions from previous samplings. Phosphorus levels dipped, but nitrogen levels were found to be almost completely unchanged.

As nutrient-driven problems like harmful algal blooms grow worse, regulators are cracking down on sources of nitrogen and phosphorus, like meat processing operations. But as those efforts have yet to make a dent in the problem, calls for additional measures are emerging.

“Anne Schechinger, Midwest director with the Environmental Working Group, said new regulations are needed, not voluntary efforts,” according to the Associated Press. “She said the Biden administration has done a lot to improve drinking water, but not enough to reduce agricultural runoff.”

Stricter regulation alone might not be enough to address the problem. For the Chesapeake Bay, one of the country’s most iconic water bodies as well as one of its most nutrient polluted, significant funding will have to be central to the solution as well.

“In the last decade alone, state and federal agencies have spent more than $2 billion on programs to help farmers in the Chesapeake region install conservation practices,” per Bay Journal. “And spending is dramatically increasing as the 2025 deadline for the Bay’s cleanup goals approaches.”

With nitrogen and phosphorus levels proving to be more stubborn than officials hoped, additional regulation, funding, and technological innovation are likely on the horizon for wastewater treatment operations.


Source: Water Online


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