Sandra Dworatzek (Ontario) will present “Bioremediation Options for 1,4-Dioxane” and and Duane Graves will present “Benefits of SARS-CoV-2 Virus Analyses of Wastewater and Pooled Saliva Samples” at the virtual AEHS – 30th Annual International Conference on Soil, Water, Energy and Air.

Sandra’s co-presenter is Chao Zhou, Geosyntec Consultants.

Sandra is a Principal Scientist with more than 25 years of experience in bioremediation of chlorinated solvents, petroleum hydrocarbons, emerging contaminants and other recalcitrant compounds. She has specific technical experience in the design of laboratory treatability studies, the scale up of growth of aerobic and anaerobic microbial cultures for bioaugmentation laboratory and field pilot tests, and evaluation of aerobic and anaerobic bioremediation, zero valent iron and chemical oxidation technologies in the laboratory. She currently provides senior technical oversight of laboratory treatability studies and the development and scaleup of new bioaugmentation cultures, including novel cultures for BTEX compounds under anaerobic conditions and aerobic 1,4-dioxane bioremediation. Sandra currently is the industry lead on a Genome Canada funded project for the commercialization of anaerobic BTEX degrading cultures.

Duane Graves is a Senior Principal Scientist based in Tennessee with more than 30 years of experience focused on environmental biotechnology; environmental forensics; in situ groundwater, soil, and sediment remediation; evaluation of airborne biological contaminants; and remediation of groundwater in karst formations.

March 2021 will mark the thirtieth annual gathering of environmental professionals for the Conference on Soil, Water, Energy, and Air. For the past twenty-nine years, this annual conference has helped bring the environmental science community closer together by providing a forum to facilitate the exchange of information of technological advances, new scientific achievements, and the effectiveness of standing environmental regulation programs. The 30th International Conference on Soil, Water, Energy, and Air and AEHS Foundation Semi-Annual Meeting offers attendees an opportunity to exchange findings, ideas, and recommendations in a professional virtual setting. The strong and diverse technical program is customized each year to meet the changing needs of the environmental field.

The Association for Environmental Health and Sciences Foundation, Inc. (AEHS) is a non-profit, member-supported, professional organization. Our purpose is to facilitate communication and foster cooperation among professionals concerned with the challenge of soil, sediment, and water assessment, cleanup, and protection.

With nearly three decades of relationship building and service, we know that resolutions for environmental contamination can be found only through the integration of scientific and technological discovery, social and political judgment, and hands-on practice. AEHS Foundation facilitates conferences, seminars, publications, collaborative partnerships, and our members-only online community.

Founded in 1990 as the Association for Environmental Health of Soils, AEHS has provided an international forum for over 600 members, industry experts, researchers, and governmental organizations to exchange information and advance awareness of environmental issues. The AEHS network spans professional disciplines from across the U.S. and abroad including biology, chemistry, geology and hydrogeology, engineering, and regulatory science.


Title: Bioremediation Options for 1,4-Dioxane
Time: 2:30 p.m. EDT on March 24, 2021
1,4-dioxane (1,4-D) is a probable carcinogen commonly detected in groundwater due to its use as a solvent stabilizer. The high solubility of 1,4-D often leads to large dilute plumes with associated remediation challenges. Fortunately, available options for implementing bioremediation in 1,4-D contaminated groundwater are increasing.

Aerobic cometabolic bioventing utilizes the addition of oxygen and alkane gases to groundwater and has been tested in the lab and successfully implemented in the field. For example, at a DoD site in Arizona, sequential methane and oxygen gas infusion was used to enhance cometabolic 1,4-D degradation1. Delivery of sufficient oxygen was identified as a major challenge for in situ bioremediation of 1,4-D and in some cases may favor ex situ approaches, such as bioreactors.

Bioremediation of 1,4-D by aerobic energy yielding pathways has growing promise.  A major milestone was the discovery of Pseudonocardia dioxanivorans CB11902, a microorganism that uses 1,4-D as an energy source. Other metabolic cultures, which can be used for bioaugmentation, have been developed from ex situ bioreactors. In laboratory microcosms for a confidential site, both cometabolic and bioaugmentation treatments using a metabolic 1,4-D culture, achieved complete removal of 1,4-D was within 100 days.  Given, the technical complexity of applying a cometabolic remedy in the field (adding both an alkane gas and oxygen), bioaugmentation with the metabolic culture was the selected as the remedy for a field pilot-test, currently in planning. Available field results from this pilot test will be discussed.

Phytoremediation has also been deployed successfully at 1,4-D sites in North America and in Europe. Phytoremediation is an application of bioremediation that can provide hydraulic control, remove 1,4-D from groundwater and deliver of oxygen to groundwater, encouraging microbial biodegradation of 1,4-D in the rhizosphere3. Interest in phytoremediation paired with bioaugmentation is growing and the potential for this combined approach for treatment of 1,4-D plumes and to address co-contaminant phytotoxicity will be discussed.


1Sadeghi, Venus et al. Cometabolic Bioremediation of TCE and 1,4-Dioxane with Methane and Oxygen at Air Force Plant 44.
Third International Symposium on Bioremediation and Sustainable Environmental Technologies, Miami, FL; May 2015.

2Mahendra, S. and L.A. -Alvarez-Cohen. 2006. Kinetics of 1,4-Dioxane Biodegradation by Monooxygenase-Expressing Bacteria
Environ. Sci. Technol.  40, 5435-42.

3Gestler, Ron et al. Phytoremediation of 1,4-Dioxane Contaminated Aquifers – Case Studies and Lessons Learned. Bioremediation and Sustainable Environmental Technologies—2017. Fourth International Symposium on  Bioremediation and Sustainable Environmental Technologies Miami, FL; May 2017

Title: Benefits of SARS-CoV-2 Virus Analyses of Wastewater and Pooled Saliva Samples
Time: 1:00 p.m. EDT on March 23, 2021
The global COVID-19 pandemic has affected all aspects of our communities, businesses, and the economy. Using existing technology, scientists can support efforts to combat this viral outbreak while a vaccine is being developed and deployed. SARS-CoV-2 (aka novel coronavirus) is the virus that causes the COVID-19 disease. Genetics laboratories have been using Reverse Transcriptase-quantitative Polymerase Chain Reaction (RT-qPCR) to analyze DNA and RNA for decades. Within the last year, this method has been modified to specifically analyze for the RNA of the novel coronavirus not only for clinical purposes but also for environmental samples.

Infected humans, whether symptomatic or asymptomatic, shed the novel coronavirus in their feces. Studies have shown that the novel coronavirus can remain detectable in wastewater for at least 48 hours. Recent efforts in Europe and the US have been able to successfully detect the novel coronavirus in wastewater using RT-qPCR and use these data to track viral baselines in a community. When infection rates go up, the viral loads go up. Analysis of saliva also has been used successfully for surveillance purposes. Saliva from up to 100 individuals can be combined into one “pooled sample” and analyzed for the coronavirus. By this method, many people can be screened with a single test. If the virus is not detected, the entire pool of individuals is considered to be free of the virus. If the virus is detected, then all individuals within that pool are individually tested using clinical RT-qPCR analyses to identify those infected with the virus.

Most interesting is that increases in viral loads can be observed in saliva and wastewater up to two weeks before infections are being reported in the community – because of asymptomatic and pre-symptomatic infected carriers who shed viruses prior to displaying clinical symptoms. Communities can use these data to issue stay at home orders, social distancing guidelines, business operating practices, mask usage directives, gathering restrictions, and other actions that are intended to stem the transmission of the virus. The effect of these measures can be monitored by the virus concentration in wastewater and saliva as well as epidemiological and clinical data.

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