CCWT Research Finds Likely Source of 1,4-dioxane in Wastewater and Novel Approach for Removal

From Twin University Studies Reveal Contamination of Public Water Supplies by Household Products Containing Likely Human Carcinogen and the Creation of a New Septic System to Remove This, Nitrogen, and Other Contaminants from the New York State Center for Clean Water Technology

Friday, February 26, 2021 – There is growing concern across the country regarding the contamination of drinking water supplies by toxic chemicals. From lead in Flint, Michigan, to perfluoroalkyl substances found in public water supplies across the country, clean public water has become a central environmental issue. While these contaminants are also of concern across Long Island where the likely human carcinogen, 1,4-dioxane, has been found at the highest levels ever measured in drinking water across the U.S. due to a large industrial plume. More recently, there has been the suggestion that beyond industrial contamination, 1,4-dioxane is also present at very high levels in common household products such as detergents, deodorants, and shampoos but evidence of this has been lacking.

Now, emerging research from the New York State Center for Clean Water Technology affirms household products as a likely source of 1,4-dioxane in wastewater, but also reveals a novel approach for removing this chemical and other contaminants before it enters groundwater.

Founded in 2015, a prime mission of the Center has been to solve the nitrogen overloading crisis in Long Island’s groundwater and surface waters by developing innovative and alternative onsite septic systems. Excessive nitrogen has shown to cause harmful algal blooms, the loss of important aquatic habitats like seagrass meadows, and the collapse of shellfisheries like clams and scallops; high nitrate in drinking water is also a public health concern. The Center has developed a series of innovative Nitrogen Removing Biofilters (NRBs) that is comprised of layers of natural products commonly found across Long Island, sand and woodchips. In a new paper published in the international peer-reviewed journal Ecological Engineering , scientists from the Center demonstrates that their NRBs installed in Massachusetts and NY remove up to 80 – 90% of nitrogen from wastewater before it is discharged to ground.

Dr. Chris Gobler, Director of the New York State Center for Clean Water Technology (CCWT), “In 2015, we set a goal to develop a septic system that reduces nitrogen from wastewater to less than 10 milligrams of nitrogen per liter; with this publication we’re showing the world we’ve met that goal and can achieve nitrogen levels lower than any commercially available system”, said Gobler.

Beyond nitrogen, the Center is also focused on the ability of NRBs to remove other contaminants of concern, including 1,4-dioxane. In addition to monitoring nitrogen, the Center has been collecting samples from homes outfitted with NRB septic systems; specifically collecting tap water, representing water entering the homes, influent wastewater, representing sewage exiting homes and entering the NRBs, and effluent (treated wastewater) exiting from the NRBs before it enters groundwater and Long Island’s drinking water supply.

In a paper published this month in the international peer-reviewed scientific journal, Science of the Total Environment , the Center demonstrated that while tap water samples has levels of 1,4-dioxane less than one part per billion (ppb), the drinking water standard for NYS, levels of 1,4-dioxane in the wastewater leaving homes consistently contained levels higher than tap water levels, peaking as high as eight ppb, and increasing by more than ten-fold, on average. Importantly, the results also show that the treated wastewater exiting the NRBs were, on average, 56% lower than the wastewater leaving the homes and was usually less than one ppb. These analyses have two important discoveries. First, the increase in 1,4-dioxane concentrations in the wastewater exiting homes suggests household products and activity is an important source of 1,4-dioxane in wastewater. Next, the NRBs are cleaning the wastewater, reducing 1,4-dioxane concentrations to levels below the proposed NYS drinking water standard of one ppb.

The efficient removal of 1,4-dioxane from wastewater by the NRBs is a breakthrough finding, as the chemical 1,4-dioxane, is extremely difficult to remove from contaminated water supplies with advanced oxidation processes being one of the only reliable approaches. This has Stony Brook University scientists encouraged.

“The enrichment of 1,4-dioxane in water supplies by household activity and the ability of our NRBs to remove this extremely persistent, probably carcinogen has important implications for protecting water supplies”, said Gobler. “The results are very surprising and at the same time encouraging as 1,4-dioxane is expected to resist natural degradation processes and are not removed efficiently by filtration. Our team is performing controlled experiments to understand the mechanism by which 1,4-dioxane is removed by NRBs”, added Dr. Arjun Venkatesan, Associate Director for Drinking Water Initiatives, NYS CCWT.

These results could soon have broad implications for Long Island as well. NRBs just completed the experimental testing phase in Suffolk County and have entering the County’s ‘piloting test phase’. Upon the collection of 12 more months of data, NRBs will earn provisional approval in Suffolk County at which point anyone will be able to install these systems in their home. Current state, county, and town grant programs allow such systems to be installed at little-to-no cost to homeowners.

New York State Department of Environmental Conservation Commissioner Basil Seggos said, “New York State and our academic partners are leading the way in evaluating and addressing emerging contaminants like 1,4-dioxane and the threat they pose to our environment and our communities. The studies announced today bolster New York’s aggressive approach of preventing water contamination from 1,4-dioxane by eliminating it in household and personal care products, providing extensive resources including $14.5 million to support the Center for Clean Water Technology, investigating and remediating potential sources of contamination, and committing record funding for clean water infrastructure to protect drinking water quality on Long Island and across the state.”

Adrienne Esposito, Executive Director of Citizens Campaign for the Environment, said “CCE is thrilled that this new research further validates our four-year battle to ban 1,4-dioxane from products. This type of cutting-edge science will further efforts to protect drinking water and surface water from both 1,4-dioxane and nitrogen. Strong, enforceable policies based on good science is the only way we can to continue to protect our aquifer and water resources for future generations. I want to thank the team at Stony Brook for engaging in research that directly benefits public health and provides meaningful guidance for a cleaner, safer future,”.

“Last year, I worked closely with other state representatives to pass legislation to restrict the levels of 1,4-dioxane that would be permissible in household products,” said Assemblyman Steve Englebright, Chair of the Assembly Environmental Conservation Committee. “This study demonstrates how important that legislation was and how critically important it is that we now move swiftly to implement the action imposed by that bill.”

“I want to thank the New York State Center for Clean Water Technology for the amazing work they are doing to protect our region’s drinking water from 1,4-dioxane and other harmful groundwater contaminants,” said Senator Anthony Palumbo. “Their groundbreaking research on the origination of these containments not only shows us the scope of this problem but provides us with solutions on how to keep our drinking water safe. I will continue to work with our State and Federal partners to ensure we have the necessary funding and resources needed to combat 1,4-dioxane and ensure Long Islanders have access to clean and reliable drinking water for generations to come.”