1,4 Dioxane Updates

The City of Asheboro operates the W.L. Brown Water Treatment Plant with a capacity of 12 MGD (million gallons per day). The City utilizes three lakes for water supply. The major sources are Lake Lucas with 1.25 billion gallons of capacity and Lake Reese with 2.4 billion gallons of capacity. Lake Bunch serves as an auxiliary water supply. These lakes are located in the Yadkin Pee Dee River Basin. The system is continuously monitored to ensure a clean, pure water supply that meets and/or exceeds all State and Federal requirements.

Water is provided to customers within our city. These customers include industrial, commercial, and residential users. This water can be used for operation, production, and domestic purposes.  After the customers use the water the wastewater that is produced by industrial, commercial and residential customers is then sent to the Asheboro Wastewater Treatment plant for treatment. The Asheboro Wastewater Treatment Plant has the capacity to treat 9 MGD of wastewater. The City of Asheboro has a National Pollutant Discharge Elimination System Permit (NPDES) in which it must meet certain requirements, laws, and standards before it can discharge its treated wastewater into Haskett’s Creek, a class “C” stream located in the Cape Fear River Basin. Conventional wastewater treatment plants cannot remove many organic chemicals such as 1,4-Dioxane. Treatment options are limited and highly expensive, which would result in unfair burdens on rates and taxpayers.

As part of the NPDES permit, the City is required to monitor, issue and enforce state approved permits to industrial and commercial users. These industrial permits must follow the same laws and regulations as the Asheboro Wastewater Treatment Plant. These permits are designed to limit industrial discharges to protect the Asheboro Wastewater Treatment Plant as well as the environment.

According to the EPA Technical Fact Sheet, 1,4-Dioxane is a synthetic industrial chemical that is completely miscible in water. It is classified by EPA as “likely to be carcinogenic to humans” however there is no federal maximum contaminant level for drinking water. It is a byproduct present in many goods including paint strippers, dyes, greases, antifreeze, and some consumer products such as deodorants, shampoos and cosmetics. It is used as a purifying agent in the manufacturing of pharmaceuticals and is a byproduct in the manufacturing of polyethylene terephthalate (PET) plastic. 1,4-Dioxane does not bioaccumulate, biomagnify or bioconcentrate in the food chain and is readily metabolized and removed from the body. 

Understanding the Risks

Between 2013 and 2015, EPA required drinking water systems to complete the Unregulated Contaminant Monitoring Rule 3 (UCMR3). This rule required water systems all over the United States to test their drinking water for 28 chemicals and 2 viruses. 1,4-Dioxane was one of the 28 chemicals that was tested for during this time. NCDEQ notified Asheboro in March 2015 that water downstream of the discharge from the Wastewater Treatment Plant contained elevated levels of 1,4-Dioxane. The City of Asheboro conducted a full site assessment of all chemicals and processes to be sure we were not adding 1,4-Dioxane unknowingly into our treatment process. No sources of 1,4-Dioxane were found internally. Asheboro staff began Wastewater trunkline monitoring in March 2015 with the hopes of identifying sources of 1,4-Dioxane within our collection system. Two (2) industrial sources were identified shortly after sampling and discussions with the industries began as well as voluntary reductions. By 2017, a new source had connected to the Asheboro Wastewater Treatment system and discussions continued with industries around source reductions.

PET Manufacturing – One source was identified as a manufacturer of PET plastic. PET plastic is a lightweight, strong plastic and recyclable material most commonly used in beverage bottles and food packaging. During the chemical reaction used to produce PET plastic (ethoxylation), water and other by-products are created, one of those being 1,4-Dioxane. From 2017 – 2019, this industry spent millions of dollars researching and engineering a treatment unit for 1,4-Dioxane that could meet their site-specific challenges. This unit was installed voluntarily and is a state-of-the-art, one-of-a-kind system. The unit was installed in November 2020, and various operational lessons have been learned along the way. Efforts continue to refine this treatment process and reduce 1,4-Dioxane spikes and releases due to equipment upsets and failures.

Centralized Waste Treatment (CWT) – Another source was identified to be a centralized waste treatment facility. These industries follow strict federal, state and local rules. They take the process wastewater from other industries and treat it in a treatment system before discharging according to their industrial user permit to a Publicly Owned Treatment Works (POTW). Our local CWT voluntarily opted to screen their accepted waste streams for 1,4-Dioxane and refuse acceptance of any potential 1,4-Dioxane containing streams, thus eliminating their discharge of 1,4-Dioxane.

Municipal Solid Waste Facility – Our last source was identified as a municipal solid waste disposal facility. This industry, much like Asheboro Wastewater Plant, does not make, or contribute 1,4-Dioxane directly, however it is present in the products and waste consumers dispose of each day at their site. This industry is currently conducting a multi-option study on how to eliminate and/or treat their wastewater before discharging to Asheboro POTW. Options being evaluated in this study are currently awaiting state review, permitting, and approval.

It is important to note the Asheboro Drinking Water system is not affected in any way by 1,4-Dioxane discharges to our Wastewater Treatment Plant. Our drinking water is sourced from the Yadkin Pee Dee River Basin and treated by our water treatment plant to all applicable federal and state standards and then delivered to your faucet.

While City of Asheboro staff work with industrial and commercial users to reduce their 1,4-Dioxane discharges there are many things you as residents can do at home to help. The following link is from a 2019 Consumer Shopping Guide. This guide provides specific products and the 1,4-Dioxane concentrations of each.

Consumers can also check the ingredient labels of soaps, detergents, deodorants, and cosmetics and avoid products with any chemicals ending in -eth, -oxynol or PEG-. For example, Sodium LaurETH Sulfate.

Residents can also view the EPA Safer Choice website at https://www.epa.gov/saferchoice to find products that are safer for human health and the environment.

The City of Asheboro is continuing to evaluate and focus on areas where changes may be possible to help reduce 1,4-Dioxane.  Asheboro participates in ongoing work with NCDEQ and local Industrial Users. Currently Asheboro collects voluntary weekly effluent grab & composite samples, collection system samples, and stream samples for monitoring and data collection purposes. Additionally, Asheboro is collecting and reviewing information on the existing wastewater treatment system to evaluate the possibility of an affordable option to assist in the reduction of 1,4-Dioxane levels that come into the Asheboro Wastewater Treatment Plant. As stated above, 1,4-Dioxane is not only an industry issue, but is also found in household items used daily by the public. While these domestic levels are considered uncontrollable, the evaluation of current treatment could potentially lead to modifications that further minimize 1,4-Dioxane.

Individual Industrial User Permits are also being evaluated to determine if additional reductions are possible. For example, one of Asheboro’s permitted industries is currently conducting an in-depth study to determine the best possible treatment method for their specific waste stream. This type of study can be time consuming due to the lengthy data collection period, results analysis, plan development, and the final construction phase. Additional testing is then conducted to ensure adequate treatment. Studies such as this are necessary since an appropriate treatment system is critical for each waste stream need.

The City of Asheboro is confident that with the ongoing effort and work being conducted by our City, State, local industries and community, Asheboro will be able to build a strong foundation for reduction of this pollutant.