Author: Areen Banerjee, Technical Project Manager

Groundwater contamination is an issue that affects the health and safety of populations worldwide. One of the emerging contaminants of concern is 1,4-Dioxane, a synthetic industrial chemical that has been found in more than 20% of US drinking water supplies. This compound is notoriously difficult to degrade, posing a persistent environmental challenge. However, recent advancements in bioremediation provide an innovation to clean up this ‘forever chemical.’

The U.S. Environmental Protection Agency (EPA) has set a Health Reference Level (HRL) for 1,4-Dioxane at 0.35 to 35 µg/L, yet no federal standards have been established, leaving regulation to individual states. Traditional 1,4-Dioxane remediation methods, such as chemical oxidation and co-metabolism, are effective but come with their own set of challenges, including oxygen depletion, excessive costs, and the potential use of hazardous substrates.

A Transformative Approach

Allonnia’s 1,4 D-Stroy™ is a novel organism that that metabolically degrades 1,4-Dioxane and has advantages over other microbial solutions in the field. This gram-positive aerobic bacterium is naturally occurring, non-sporulating, and easy to cultivate. It does not require selective pressure of 1,4-Dioxane to maintain its degradation phenotype.

Field demonstrations of 1,4 D-Stroy™ in Pennsylvania, Southern California, and South Carolina have shown promising results. In Pennsylvania, a 97.5% reduction of 1,4-Dioxane was achieved, outperforming the previously tested CB1190. Southern California’s first Allonnia field trial saw a 97% reduction, and South Carolina’s first field study using direct push technology resulted in a 50% initial reduction. The learnings from field deployment posed some interesting questions that needed to be answered in a controlled lab environment.

Characterization of 1,4 D-Stroy™

1,4 D-Stroy™ degrades 1,4-Dioxane in groundwater metabolically at concentrations as low as 200 parts per billion (ppb). We have seen some challenges in performance at 100 ppb but found that the addition of simple carbon sources like glucose or yeast extract can enhance degradation, especially under low 1,4-Dioxane conditions.

Overcoming Obstacles

One of the concerns with deploying biological solutions in the field is their ability to persist and remain effective over time. The Southern California trial suggests that 1,4 D-Stroy™ can survive in groundwater for over six months post-inoculation, continuing to degrade 1,4-Dioxane using natural carbon sources available in the field. This robustness is further supported by the fact that 1,4 D-Stroy™ cultures remained active after more than six months of storage at 4°C.

Looking Ahead

The journey of 1,4 D-Stroy™ from discovery to deployment is a testament to the power of innovative bioremediation strategies. As we continue to face environmental challenges, the development of such transformative solutions offers a ray of hope for cleaner, safer groundwater. The collaborative efforts of researchers, engineers, and environmental scientists are paving the way for a future where contaminants like 1,4-Dioxane are no longer a threat to our precious water resources.

I presented this topic at Battelle’s 2024 Chlorinated Conference; you can view the presentation here. If you would like to learn more about how our 1,4 D-Stroy in situ solution can work for your site, contact us to connect with an Allonnia expert.